Journal of Vascular Surgery

From the Editors

2008-12-01

With this issue of the Journal, we complete our 6 year term as editors. It has been a privilege for us to serve in this capacity and we have learned much in the process. Most gratifying has been our interaction with Editorial Board Members, reviewers and authors as we all strive to advance the discipline of vascular surgery. We extend our congratulations and best wishes to the new editors, Drs. Tony Sidawy and Bruce Perler.

Early and midterm results after endovascular stent graft repair of penetrating aortic ulcers

2008-12-01

Purpose: To present early and midterm results after endovascular stent graft repair of patients with penetrating aortic ulcers (PAU).Methods: Between January 1997 and March 2008, a total of 202 patients received thoracic aortic endografting in our institution, 48 patients (32 men, median age 70 years, range, 48-89) with PAU. A retrospective analysis of these patients was performed. Thirty-one patients (65%) showed an acute aortic syndrome (8 contained rupture, 23 symptomatic). Follow-up scheme included postoperative computed tomography angiography prior to discharge, at 3, 6, and 12 months, and yearly thereafter. Mean follow-up was 31.3 months (1.3-112.6).Results: Technical success was achieved in 93.7%. Primary clinical success rate was 81.2%. In-hospital mortality was 14.6%. Perioperative mortality was significantly (P = .036) higher in patients with acute aortic syndrome compared to asymptomatic patients (22.5% vs 0%). Postoperative complications occurred in 15 patients (31%), including 2 patients with minor strokes and 6, respectively, 5 patients with cardiac and/or respiratory complications. Early endoleaks were observed in 9 patients (19%), late endoleaks in another 2 patients. Reintervention was necessary in 4 out of 48 patients (8.4%). The actuarial survival estimates at 1, 3, and 5 years were 78% ± 6%, 74% ± 7%, and 61% ± 10%, respectively. There was no aortic-related death during follow-up. Cox regression showed age (hazard ratio [HR]; 1.08, P = .036) and a maximum aortic diameter >50 mm (HR, 4.92; P = .021) as independent predictors of death.Conclusion: Endovascular treatment of penetrating aortic ulcers is associated with a relevant morbidity and mortality rate in frequently highly comorbid patients. Midterm results could prove a sustained treatment success regarding actuarial survival and aortic-related death. Emergencies show a significantly worse outcome, but treatment is still warranted in these symptomatic patients.

Immediate endovascular repair for acute traumatic injuries of the thoracic aorta: A multicenter analysis of 28 cases

2008-12-01

Objective: Endovascular repair of injured thoracic aorta offers a new minimal invasive therapeutic option that could be beneficial in the urgent management of polytrauma patients. The aim of this study was to assess our multicenter experience of immediate endovascular repair for acute traumatic injuries of the thoracic aorta.Methods: Between April 2002 and October 2007, all patients treated for an acute traumatic injury of the thoracic aorta, in a less than 12-hour delay, by endovascular repair, were reviewed retrospectively in three Parisian trauma centers. Collected data included age, sex, associated comorbidities, and traumatic lesions to determine the Traumatic Injury Severity Score (TRISS), the type of aortic lesion assessed by computed tomography (CT)-scan and transesophageal ultrasonography, technical aspects of endovascular repair, length of hospital stay, and postoperative mortality. Patients were regularly followed by clinical examination, chest radiographs, and thoracic CT-scan.Results: Twenty-eight patients (20 males, mean age 45 ± 18.8 years) were treated in a median delay of 5 hours (range 2 to 10 hours) after initial trauma. They all experienced severe traumatic injuries with a mean predictive mortality of 55.6% ± 33.1% according to TRISS. Aortic lesions were associated with aortic parietal hematoma (71%), hemomediastinum (86%), and hemothorax (68%). All endovascular procedures were technically successful through femoral (n = 24) or iliac access (n = 4), in a mean operating time of 94 ± 35.8 minutes. Proximal sealing of the endografts required the coverage of the origin of the left subclavian artery in 13 cases and of the left common carotid in one case. The median of hospital stay was 27 days (range 9 to 127 days), with an overall hospital mortality of 17.9% (n = 5). All deaths were unrelated to the aortic rupture or the stent placement, and no intervention-related morbidity or mortality was recorded during a median follow-up of 24 months (range 5 to 73 months).Conclusion: Endovascular stent grafting allows an immediate efficient repair for acute traumatic injuries of the thoracic aorta. This early management is, however, associated with a high in-hospital mortality, related to the severe concomitant injuries of such unselected multitrauma patients.

Fit patients with small abdominal aortic aneurysms (AAAs) do not benefit from early intervention

2008-12-01

Objectives: The UK Small Aneurysm Trial (UKSAT) and the American Aneurysm Detection and Management (ADAM) trial both concluded that early elective open surgery does not confer any late survival advantage in patients with small abdominal aortic aneurysm (AAA) with diameter 4.0 to 5.5 cm. However, two trials of endovascular aneurysm repair in small AAA have started based upon speculation that a sub-group of particularly fit patients, with low operative mortality, may benefit from early intervention. Here we investigate whether the fittest patients from the UKSAT might have benefited from early intervention.Methods: A total of 1090 patients randomized into the UKSAT between 1991 and 1995 were followed for an average of 12 years for mortality. Baseline data were used to calculate the Customized Probability Index (CPI), a validated prognostic risk score for operative mortality after elective open aneurysm repair that assigns risk points for history of cardiac, pulmonary, and renal disease and subtracts risk points for use of statins and beta-blockers. Cox regression was used to assess any differences in all-cause or aneurysm-related mortality between policies of early surgery or surveillance across the fitness spectrum. Tests for interaction used CPI scores as a continuous variable but patients also were stratified into tertile groups for descriptive purposes. Hazard ratios were adjusted for age, gender, and aneurysm diameter.Results: A total of 714 deaths (95 aneurysm-related) occurred in 8485 person-years (number of patients multiplied by average years of conditional follow-up). The mean (standard deviation [SD]) CPI score was 8.1 (9.9) with similar scores between randomized groups. The tertile groups had mean (SD) scores of −1.8 (3.7) for the 389 fittest patients, 8.8 (3.3) for the 438 moderately fit, 21.4 (6.6) for the 261 least fit with missing scores in 2 patients. The tests for interaction were non-significant for both all-cause (P = .176) and aneurysm-related mortality (.178). However, for the least fit patients a survival advantage was seen in the early surgery group; adjusted hazard ratios 0.73 (95% confidence interval [CI] 0.56-0.96) and 0.46 (95% CI 0.22-0.98) for all-cause and aneurysm-related mortality respectively.Conclusion: Early elective surgery did not confer any survival benefit in the fittest patients. On the contrary, the possibility of a survival benefit from early intervention in patients of poor fitness merits further investigation through meta-analysis or validation in other prospective studies.

Outcomes of endovascular abdominal aortic aneurysm repair compared with open surgical repair in high-risk patients: Results from the Swedish Vascular Registry

Carl Magnus Wahlgren, Jonas Malmstedt, Swedish Vascular Registry — 2008-12-01

Background: The management of infrarenal aortic aneurysms in high-risk patients remains a challenge. Endovascular aneurysm repair (EVAR) is associated with superior short-term mortality rates but unclear long-term results and has not been shown to improve survival in patients unfit for open repair (OR). The aim of this population-based study was to evaluate the outcome after elective EVAR compared with OR in a high-risk patient cohort.Methods: Prospectively collected data from January 2000 to December 2006 were retrieved from the Swedish Vascular Registry. The high-risk cohort was defined as age ≥60 years, American Anesthesiologists Association (ASA) class 3 or 4, and at least one cardiac, pulmonary, or renal comorbidity. These criteria were met by 217 of 1000 EVAR patients and 483 of 2831 OR patients. Primary end points were 30-day and 1-year all-cause mortality. Kaplan-Meier curves for survival and multivariate Cox regression analyses were performed.Results: The crude 30-day and 1-year all-cause mortality rates for EVAR vs OR for the whole treatment group (n = 3831) were 1.8% vs 2.8% and 8.0% vs 7.2%, respectively. In the high-risk cohort (n = 700), EVAR patients were approximately 2 years older and renal insufficiency and diabetes mellitus were more common, and smoking was more prevalent in the OR group. About two-thirds of EVAR procedures were performed at university hospitals and one-half of OR procedures were performed at county hospitals. In the high-risk cohort, there was no difference in mortality at 30-days (EVAR, 4.6% vs OR, 3.3%), but OR had lower 1-year mortality (8.5% vs 15.9%; P = .003). More bleeding complications occurred in the EVAR group, but more pulmonary complications occurred in the OR group; however, there was no difference in cardiac, cerebrovascular, or renal complications. The mean follow-up was 3.4 years. EVAR was associated with increased mortality risk after adjusting for age, ASA class, and comorbidities (hazard ratio, 1.50; 95% confidence interval, 1.07-2.12; P = .02). Kaplan-Meier survival analysis showed a lower mortality rate for patients undergoing OR, which remained during follow-up (P = .001).Conclusions: Elective OR of aortic aneurysms seems to have a better outcome compared with EVAR in this specific, population-based, high-risk patient cohort after adjusting for covariates. We cannot confirm the benefit of EVAR from previous registry studies with a similar high-risk definition. In clinical practice, OR may be at least as good as EVAR in high-risk patients fit for surgery.

Invited commentary

Jaap Buth — 2008-12-01

The Swedish Vascular Registry (Swedvasc) is a long standing national project used for auditing outcome of a variety of vascular procedures. The authors for the Swedish Vascular Registry (Swedvasc) have assessed the outcome of endovascular repair in patients at high-risk for surgical treatment of their abdominal aortic aneurysm in comparison to open surgery. A comparison of this type from registry data carries the risk of unequal distribution of co-morbid factors between treatment groups. The authors selected two studies with a similar design for comparison with their own series. The first study, a Veterans Administration study, was reported by Bush et al and the second by Sicard et al. These US studies both concluded from their operative and late mortality data that patients with infrarenal abdominal aortic aneurysm with considerable medical co-morbidities benefit from and should be considered for primary endovascular aneurysm repair (EVAR). The authors of the Swedvasc study came to an opposite conclusion in that they could “not confirm the benefit of EVAR from these previous registry studies with a similar high-risk definition”, and “in clinical practice, open repair may be at least as good as EVAR in high-risk patients fit for surgery”. The conclusion was based on a relatively high all-cause mortality in EVAR patients during follow-up. However, a clear explanation for the striking difference of their results with the two US studies was not provided. Causes of death were not available in their database and “aneurysm-related death” was disposed as an unreliable variable.

Reimbursement of long-term postplacement costs after endovascular abdominal aortic aneurysm repair

2008-12-01

Objective: Postplacement cost of surveillance and secondary procedures over 5 years increases the global cost of endovascular aortic aneurysm repair (EVAR) by nearly 50%. This study identified and assessed the reimbursement received for long-term postplacement costs after EVAR.Methods: Between December 1995 and June 2007, 360 patients underwent EVAR at a single institution. The reimbursement collected from charges of postplacement surveillance and secondary procedures related to the aneurysmal disease was evaluated and compared against the actual costs. All amounts were converted to year 2007 dollars. To minimize costs associated with the early learning curve, the initial 50 EVAR patients between December 1995 and 1998 were excluded. Patients with <1 year follow-up were also excluded. Data are expressed as mean ± standard error.Results: The mean follow up after EVAR for 152 patients was 38.8 ± 1.8 months. Medicare, capitated insurance, and commercial insurance provided coverage for 85 (56.0%), 49 (32.2%), and 18 (11.8%) patients, respectively. The cumulative 5-year postplacement reimbursement received per patient was $9792 meeting 81.4% of the cumulative cost of $12,027 for a net loss of $2235 per patient. Although 123 (80.9%) patients without secondary procedures generated a 5-year cumulative gain of $1830 per patient, 29 (19.1%) patients with secondary procedures averaged a 5-year cumulative loss of $9378 per patient. The average reimbursement rate over the 5-year period was 35.8% ± 0.6%, with the lowest reimbursement rate seen in patients with Medicare at 31.6% ± 0.7%.Conclusion: Current reimbursement is not sufficient to meet the costs associated with long-term surveillance and needed secondary procedures after EVAR. Inadequate reimbursement of costs associated with secondary procedures was the primary driver for the net institutional loss. Reimbursement for outpatient radiological procedures generated a modest surplus.

Mortality of ruptured abdominal aortic aneurysm treated with open or endovascular repair

2008-12-01

Objectives: The study defined the selection criteria used for treatment of ruptured abdominal aortic aneurysms (RAAAs) and reviewed results during a 5-year period.Methods: From 2002 on, our tertiary referral center adopted a protocol of selective use of endovascular repair for RAAAs. The study included all patients with a proven RAAA who were admitted to our hospital from 2002 to 2006. The primary outcome measure was surgical mortality.Results: A total of 187 patients were admitted with an acute AAA, and an RAAA was confirmed 135 (72%) by computed tomography scanning or at laparotomy, and 125 (93%) were treated, 89 by open means and 36 by endovascular means. The overall mortality rate was 24% and the mortality rate was 13.9% for endovascular repair. Endovascular repair was consistently used more often in patients with favorable anatomy and in patients who were hemodynamically more stable. There were considerable differences in approach between the four consultant vascular surgeons. The overall evaluation and inclusion for endovascular treatment increased during the study period.Conclusions: A strict protocol for admission, evaluation, and treatment of RAAA, with selective use of endovascular repair, resulted in low mortality rates in our center.

Biomechanical properties of abdominal aortic aneurysms assessed by simultaneously measured pressure and volume changes in humans

2008-12-01

Background: Abdominal aortic aneurysms (AAA) are at risk of rupture when the internal load (blood pressure) exceeds the aneurysm wall strength. Generally, the maximal diameter of the aneurysm is used as a predictor of rupture; however, biomechanical properties may be a better predictor than the maximal diameter. Compliance and distensibility are two biomechanical properties that can be determined from the pressure-volume relationship of the aneurysm. This study determined the compliance and distensibility of the AAA by simultaneous instantaneous pressure and volume measurements; as a secondary goal, the influence of direct and indirect pressure measurements was compared.Methods: Ten men (aged 73.6 ± 6.4 years) with an infrarenal AAA were studied. Three-dimensional balanced turbo field echo (3D B-TFE) images were acquired with noncontrast-enhanced magnetic resonance imaging (MRI) for the aortic region proximal to the renal arteries until just beyond the bifurcation. Volume changes were extracted from the electrocardiogram-triggered 3D B-TFE MRI images using dedicated prototype software. Pressure was measured simultaneously within the AAA using a fluid-filled pigtail catheter. Noninvasive brachial cuff measurements were also acquired before and after the imaging sequence simultaneously with the invasive pressure measurement to investigate agreement between the techniques. Compliance was calculated as the slope of the best linear fit through the pressure volume data points. Distensibility was calculated by dividing the compliance by the diastolic aneurysmal volume. Young's moduli were estimated from the compliance data.Results: The AAA maximal diameter was 5.8 ± 0.6 cm. A strong linear relation between the pressure and volume data was found. Distensibility was 1.8 ± 0.7 × 10−3 kPa−1. Average compliance was 0.31 ± 0.15 mL/kPa with accompanying estimates for Young's moduli of 9.0 ± 2.5 MPa. Brachial cuff measurements demonstrated an underestimation of 5% for systolic (P < .001) and an overestimation of 12% for diastolic blood pressure (P < .001) compared with the pressure measured within the aneurysm.Conclusion: Distensibility and compliance of the wall of the aneurysm were determined in humans by simultaneous intra-aneurysmal pressure and volume measurements. A strong linear relationship existed between the intra-aneurysmal pressure and the volume change of the AAA. Brachial cuff measurements were significantly different compared with invasive intra-aneurysmal measurements. Consequently, no absolute distensibility values can be determined noninvasively. However, because of a constant and predictable difference between directly and indirectly derived blood pressures, MRI-based monitoring of aneurysmal distensibility may serve the online rupture risk during follow-up of aneurysms.

Repair of complex renal artery aneurysms by laparoscopic nephrectomy with ex vivo repair and autotransplantation

Katherine A. Gallagher, Michael W. Phelan, Tina Stern, Stephen T. Bartlett — 2008-12-01

Objective: Renal artery aneurysms are being discovered more frequently due to increased use of non-invasive imaging. Complex renal artery aneurysms involving multiple secondary or tertiary branches are not amenable to in vivo or endovascular treatment and often require ex vivo repair with autotransplantation. In order to minimize incisional morbidity and hasten recovery, we developed a technique of laparoscopic nephrectomy combined with backbench ex vivo repair, followed by autotransplantation through a small laparoscopic extraction incision. This study describes our initial experience with this combined technique in patients that were not candidates for endovascular techniques or in vivo arterial reconstruction.Methods: Seven patients with complex renal artery aneurysms underwent laparoscopic nephrectomy and ex vivo repair with multiple saphenous vein grafts and autotransplantation through the small laparoscopic extraction incision. The aneurysms ranged from 2.5 to 5.0 cm. In all cases, the aneurysm was resected ex vivo, leaving multiple branch arteries that were extended with saphenous vein grafts. Arterial inflow was then re-established with sequential saphenous vein anastomoses to the external iliac artery. Ureteral reconstruction was performed via standard Lich ureteroneocystostomy. Patients were followed postoperatively for two to eight years.Results: Laparoscopic nephrectomy with ex vivo repair of complex aneurysms was successfully employed in seven patients with renal aneurysms that were not amenable to endovascular or in vivo repair. There were no incisional morbidities and all patients had significant improvements in symptoms post-operatively. Renal function remained unchanged and there were no ureteral complications following surgery. All patients had postoperative ultrasound imaging done at two years which demonstrated patency of the anastomoses. The mean hospital stay was four days (range, two to seven days).Conclusion: Repair of complex renal artery aneurysms involving distal branch arteries remains a challenge. This new technique combines the advantages of minimally invasive surgery with the effectiveness of ex vivo aneurysm repair.

Efficacy of protected renal artery primary stenting in the solitary functioning kidney

2008-12-01

Background: Significant renal artery stenosis (RAS) in a solitary functioning kidney (SFK) represents one of the most acceptable indications for renal revascularization. Percutaneous transluminal renal artery stenting (PTRAS) is increasingly being used as a first line treatment for renal revascularization, associated with renal function improvement or stabilization in the majority of the patients with solitary kidneys, but also with deterioration in up to 38% of the cases. Atheroembolism during PTRAS has been postulated as a potential cause for this acute renal function worsening. The aim of this study was to report on the feasibility, safety, and early outcomes of PTRAS in a series of patients with SFK using distal embolic protection (DEP).Methods: All PTRAS procedures in SFKs performed under DEP between June 2002 and September 2007 were reviewed. Renal function, blood pressure, and the number of anti-hypertensive medications were assessed pre- and post-intervention. Renal function improvement and deterioration were defined as a 20% increase and decrease in serum creatinine, respectively, compared with preoperative values. Primary and primary assisted patency rates were also calculated. Statistical differences between values before and after intervention were determined by the Student t test and statistical significance was taken at P < .05.Results: Protected PTRAS was performed in 14 patients with a SFK (9 men, 6 women, mean age 65.6 ± 6.8 years). All patients were hypertensive and had varying degrees of azotemia. Mean pre-intervention stenosis degree was 86.8% ± 7.8%. Immediate technical success was obtained in 100% of the patients. Renal function was cured (7.1%), improved (50%), or stabilized (42.9%) in all 14 (100%) patients after the procedure and no deterioration was noticed in any patient at 6-month follow-up. Pre- and postintervention serum creatinine levels were 3.01 ± 1.15 mg/dL and 2.16 ± 0.68 mg/dL, respectively, (P = .02). Hypertension was improved in 6 (42.9%) patients and stabilized in the remaining 8 (57.1%). Primary patency was 100% and 90% at 1 and 3 years, respectively, while primary assisted patency remained 100% for the whole follow-up period (mean, 31.8 ± 19.4 months).Conclusion: These findings suggest that in patients with a SFK, protected PTRAS represents a safe and effective treatment for halting the progression of renal dysfunction to renal loss and warrants further investigation.

Effect of chronic renal insufficiency on outcomes of carotid endarterectomy

2008-12-01

Objective: Conflicting data exist regarding the effect of chronic renal insufficiency (CRI) on carotid endarterectomy (CEA) outcomes. A large database was used to analyze the effect of CRI, defined by glomerular filtration rate (GFR), as an independent risk factor of CEA.Methods: Prospectively collected data regarding CEAs performed at 123 Veterans Affairs Medical Centers as part of the National Surgical Quality Improvement Program were retrospectively analyzed. Renal function was used to divide patients into three CRI groups: normal or mild (control; GFR ≥60 mL/min/1.73 m2), moderate (GFR 30 to 59), and severe (GFR <30). Bivariate analysis and multivariate logistic regression were used to characterize risk factors and their associations with 30-day morbidity and mortality.Results: Between Jan 1, 1996, and Dec 31, 2003, 22,080 patients underwent CEA. Patients missing creatinine levels, already dialysis-dependent, or in acute renal failure just before surgery were excluded. This left 20,899 available for analysis, of which 13,965 had a GFR of ≥60, 6,423 had a GFR of 30 to 59, and 511 had a GFR of <30. The incidence of neurologic complications did not differ significantly (control, 1.7%; moderate CRI, 1.9%; severe CRI, 2.7%). The moderate CRI group experienced significantly more cardiac events (1.7% vs 0.9% for controls, P < .001). This remained predictive in the multivariate model even adjusting for all other risk factors (adjusted odds ratio [AOR], 1.6; 95% confidence interval [CI], 1.1-2.3; P = .009). The moderate CRI group also had higher rates of pulmonary complications (2.1% vs 1.3% control; P < .001; AOR, 1.3; 95% CI, 1.0-1.7; P = .031) but not 30-day mortality (P = .269). Those with severe CRI had a much higher mortality (3.1% vs 1.0% control, P < .001), which remained significant in the multivariate model (AOR, 2.7; 95% CI, 1.6-4.8; P < .001).Conclusion: Although impaired renal function does not independently increase the risk of neurologic or infectious complications, CRI is a significant negative independent risk factor in predicting other outcomes after CEA. Patients with moderate CRI (GFR, 30-59 mL/min/1.73 m2) are at increased risk for cardiac and pulmonary morbidity, but not death, and those with severe CRI (GFR <30 mL/min/1.73 m2) have a much higher operative mortality. Patients with CRI should be carefully evaluated before CEA to optimize existing cardiac and pulmonary disease. Understanding this increased risk may assist the surgeon in preoperative counseling and perioperative management.

Long-term results of carotid artery stenting

2008-12-01

Objective: Data regarding the long-term efficacy of carotid artery stenting (CAS) are still scarce. As demonstrated by several major randomized controlled trials (RCT) comparing the efficacy of carotid endarterectomy (CEA) vs medical therapy, even after successful carotid revascularization late ipsilateral stroke occurs in 5-13% at 5 years. Therefore, major concerns also remain about the durability of the CAS procedure in terms of stroke prevention. The purpose of this study was to review long-term results after carotid stent implantation in a large cohort of patients.Methods: This retrospective investigation involved 3179 CAS procedures performed at four European carotid high-volume centers. Echo-duplex scan using modified velocity criteria to recognize in-stent restenosis (ISR) and neurological examinations of all patients were carried out every 6 months after the procedure. Life-table analysis was used to determine freedom from mortality, stroke-related death, ipsilateral fatal/major stroke, and any ipsilateral stroke. Freedom from ISR and from reintervention were also reported. The secondary aim was to identify predictive risk factors for neurological complications and ISR.Results: At 5 years freedom from mortality, stroke-related death, ipsilateral fatal/major stroke, and any stroke rate were 82%, 93.5%, 93.3%, and 91.9%, respectively. The only predictor for neurological complications was the presence of neurological symptoms before CAS (hazard ratio 1.38 [CI 1.05, 1.82] P = .02). Freedom from restenosis at 1, 3, and 5 years was, respectively, 98.4%, 96.1%, and 94%. Uni- and multi-variate analyses showed that stent characteristics (material/design/free-cell area) were not significantly associated with time to in-stent restenosis or time to reintervention.Conclusion: Our long-term results in a large cohort of patients validated CAS as a durable procedure for stroke prevention. The annual rate of neurological complications after CAS was comparable to that of conventional surgery as demonstrated by large RCTs involving both symptomatic patients (North American Symptomatic Carotid Endarterectomy Trial [NASCET] and European Carotid Surgery Trial [ECST]) and asymptomatic patients (Asymptomatic Carotid Atherosclerosis Study [ACAS] and Asymptomatic Carotid Surgery Trial [ACST]).

Discussion

2008-12-01

Dr Richard Cambria (Boston, Mass). I would like to open with one question about the follow-up on the issue of restenosis. You expressed your data in actuarial methods. Can you tell us how many patients actually completed the 5-years of follow-up in terms of assessing the risk of restenosis?

Carotid artery stenting has increased rates of postprocedure stroke, death, and resource utilization than does carotid endarterectomy in the United States, 2005

James T. McPhee, Andres Schanzer, Louis M. Messina, Mohammad H. Eslami — 2008-12-01

Objective: Carotid endarterectomy (CEA) remains the procedure of choice for treatment of patients with severe carotid artery stenosis. The role of carotid artery stenting (CAS) in this patient group is still being defined. Prior single and multicenter studies have demonstrated economic savings associated with CEA compared with CAS. The purpose of this study was to compare surgical outcomes and resource utilization associated with these two procedures at the national level in 2005, the first year in which a specific ICD-9 procedure code for CAS was available.Methods: All patient discharges for carotid revascularization for the year 2005 were identified in the Nationwide Inpatient Sample based on ICD9-CM procedure codes for CEA (38.12) and CAS (00.63). The primary outcome measures of interest were in-hospital mortality and postoperative stroke; secondary outcome measures included total hospital charges and length of stay (LOS). All statistical analyses were performed using SAS version 9.1 (Cary, NC), and data are weighted according to the Nationwide Inpatient Sample (NIS) design to draw national estimates. Univariate analyses of categorical variables were performed using Rao-Scott χ2, and continuous variables were analyzed by survey weighted analysis of variance (ANOVA). Multivariate logistic regression was performed to evaluate independent predictors of postoperative stroke and mortality.Results: During 2005, an estimated 135,701 patients underwent either CEA or CAS nationally. Overall, 91% of patients underwent CEA. The mean age overall was 71 years. Postoperative stroke rates were increased for CAS compared with CEA (1.8% vs 1.1%, P < .05), odds ratio (OR) 1.7; (95% confidence interval [CI] 1.2-2.3). Overall, mortality rates were higher for CAS compared with CEA (1.1% vs 0.57%, P < .05) this difference was substantially increased in regard to patients with symptomatic disease (4.6% vs 1.4%, P < .05). By logistic regression, CAS trended toward increased mortality, OR 1.5; (95% CI .96-2.5). Overall, the median total hospital charges for patients that underwent CAS were significantly greater than those that underwent CEA ($30,396 vs $17,658 P < .05).Conclusions: Based on a large representative sample during the year 2005, CEA was performed with significantly lower in-hospital mortality, postoperative stroke rates, and lower median total hospital charges than CAS in US hospitals. As the role for CAS becomes defined for the management of patients with carotid artery stenosis, clinical as well as economic outcomes must be continually evaluated.

The management of severe aortoiliac occlusive disease: Endovascular therapy rivals open reconstruction

2008-12-01

Objective: Aortobifemoral bypass (ABF) grafting has been the traditional treatment for extensive aortoiliac occlusive disease (AIOD). This retrospective study compared the outcomes and durability of recanalization, percutaneous transluminal angioplasty, and stenting (R/PTAS) vs ABF for severe AIOD.Methods: Between 1998 and 2004, 86 patients (161 limbs) underwent ABF (n = 75) or iliofemoral bypass (n = 11), and 83 patients (127 limbs) underwent R/PTAS. All patients had severe symptomatic AIOD (claudication, 53%; rest pain, 28%; tissue loss, 12%; acute limb ischemia, 7%). The analyses excluded patients treated for aneurysms, extra-anatomic procedures, and endovascular treatment of iliac stenoses. Original angiographic imaging, medical records, and noninvasive testing were reviewed. Kaplan-Meier estimates for patency and survival were calculated and univariate analyses performed. Mortality was verified by the Social Security database.Results: The ABF patients were younger than the R/PTAS patients (60 vs 65 years; P = .003) and had higher rates of hyperlipidemia (P = .009) and smoking (P < .001). All other clinical variables, including cardiac status, diabetes, symptoms at presentation, TransAtlantic Inter-Society Consensus stratification, and presence of poor outflow were similar between the two groups. Patients underwent ABF with general anesthesia (96%), often with concomitant treatment of femoral or infrainguinal disease (61% endarterectomy, profundaplasty, or distal bypass). Technical success was universal, with marked improvement in ankle-brachial indices (0.48 to 0.84, P < .001). Patients underwent R/PTAS with local anesthesia/sedation (78%), with a 96% technical success rate and similar hemodynamic improvement (0.36 to 0.82, P < .001). At the time of R/PTAS, 21% of patients underwent femoral endarterectomy/profundaplasty or bypass (n = 5) for concomitant infrainguinal disease. Limb-based primary patency at 3 years was significantly higher for ABF than for R/PTAS (93% vs 74%, P = .002). Secondary patency rates (97% vs 95%), limb salvage (98% vs. 98%), and long-term survival (80% vs 80%) were similar. Diabetes mellitus and the requirement of distal bypass were associated with decreased patency (P < .001). Critical limb ischemia at presentation (tissue loss, hazard ratio [HR], 8.1; P < .001), poor outflow (HR, 2; P = .023), and renal failure (HR, 2.5; P = .02) were associated with decreased survival.Conclusion: R/PTAS is a suitable, less invasive alternative to ABF for the treatment of severe AIOD. Repair of the concomitant femoral occlusive disease is often needed regardless of open or endovascular treatment. Infrainguinal disease negatively affects the durability of the procedure and patient survival.

Histopathological comparison between endofibrosis of the high-performance cyclist and atherosclerosis in the external iliac artery

2008-12-01

Introduction: High performance athletes, predominantly professional cyclists, can develop symptomatic arterial flow restriction in one or both legs during exercise. The ischemic symptoms are caused by endofibrosis and/or kinking of the external iliac artery. Because these athletes are young and have no classic risk factors for atherosclerosis, endofibrosis and atherosclerosis are considered different disease entities. We compared histology of endofibrotic lesions from young sportsmen with atherosclerotic lesions of the external iliac artery in elderly individuals.Methods and Results: Nineteen external iliac endarterectomy specimens from 18 cyclists (age 29 ± 8 years) were compared with 42 external iliac segments from 22 elderly individuals (82 ± 10 years). Ten arteries from elderly individuals revealed an intimal area that was ≥25% of the area encompassed by the internal elastic lamina and were considered atherosclerotic lesions. Stenosis was higher in patients (65% [interquartile range 50-75]) than in controls (11% [7-24]) (P < .0001). The endofibrotic lesions revealed loose connective tissue with moderate to high cellularity. Both in endofibrosis and atherosclerosis, most cells in the lesion were smooth muscle actin positive. In the endofibrosis specimens, loose fibers of collagen were observed, whereas in the atherosclerotic lesions collagen was mostly densely packed. Calcification of the lesion was not observed in endofibrotic lesions, whereas calcium deposition was observed in 80% of atherosclerotic lesions. Lymphocytes were present in 21% of endofibrotic lesions and in 80% of atherosclerotic cases. Macrophages were observed in 16% of endofibrotic lesions and in all atherosclerotic plaques. Luminal thrombosis was observed in one case of endofibrosis.Conclusion: In the external iliac artery, atherosclerotic lesions and endofibrotic lesions of high performance cyclists have distinct morphologic characteristics. Endofibrosis in the external iliac artery may serve as soil for luminal thrombosis.Clinical Relevance: Endofibrosis can be a serious clinical problem in high-performance athletes. Because endofibrosis predominantly occurs in sportsmen, most surgeons do not frequently see patients with endofibrosis. The results of the present study show that endofibrosis has distinct histologic characteristics as compared to atherosclerosis. In clinical practice, it is important to recognize patients with endofibrotic lesions, because endofibrosis and atherosclerosis require different diagnostic and therapeutic approaches.

Risk stratification in critical limb ischemia: Derivation and validation of a model to predict amputation-free survival using multicenter surgical outcomes data

2008-12-01

Background: Patients with critical limb ischemia (CLI) are a heterogeneous population with respect to risk for mortality and limb loss, complicating clinical decision-making. Endovascular options, compared with bypass, offer a tradeoff between reduced procedural risk and inferior durability. Risk stratified data predictive of amputation-free survival (AFS) may improve clinical decision making and allow for better assessment of new technology in the CLI population.Methods: This was a retrospective analysis of prospectively collected data from patients who underwent infrainguinal vein bypass surgery for CLI. Two datasets were used: the PREVENT III randomized trial (n = 1404) and a multicenter registry (n = 716) from three distinct vascular centers (two academic, one community-based). The PREVENT III cohort was randomly assigned to a derivation set (n = 953) and to a validation set (n = 451). The primary endpoint was AFS. Predictors of AFS identified on univariate screen (inclusion threshold, P < .20) were included in a stepwise selection Cox model. The resulting five significant predictors were assigned an integer score to stratify patients into three risk groups. The prediction rule was internally validated in the PREVENT III validation set and externally validated in the multicenter cohort.Results: The estimated 1-year AFS in the derivation, internal validation, and external validation sets were 76.3%, 72.5%, and 77.0%, respectively. In the derivation set, dialysis (hazard ratio [HR] 2.81, P < .0001), tissue loss (HR 2.22, P =.0004), age ≥75 (HR 1.64, P = .001), hematocrit ≤30 (HR 1.61, P = .012), and advanced CAD (HR 1.41, P = .021) were significant predictors for AFS in the multivariable model. An integer score, derived from the ß coefficients, was used to generate three risk categories (low ≤ 3 [44.4% of cohort], medium 4-7 [46.7% of cohort], high ≥8 [8.8% of cohort]). Stratification of the patients, in each dataset, according to risk category yielded three significantly different Kaplan-Meier estimates for 1-year AFS (86%, 73%, and 45% for low, medium, and high risk groups, respectively). For a given risk category, the AFS estimate was consistent between the derivation and validation sets.Conclusion: Among patients selected to undergo surgical bypass for infrainguinal disease, this parsimonious risk stratification model reliably identified a category of CLI patients with a >50% chance of death or major amputation at 1 year. Calculation of a “PIII risk score” may be useful for surgical decision making and for clinical trial designs in the CLI population.

Cost-effectiveness of endovascular revascularization compared to supervised hospital-based exercise training in patients with intermittent claudication: A randomized controlled trial

2008-12-01

Background: The optimal first-line treatment for intermittent claudication is currently unclear.Objective: To compare the cost-effectiveness of endovascular revascularization vs supervised hospital-based exercise in patients with intermittent claudication during a 12-month follow-up period.Design: Randomized controlled trial with patient recruitment between September 2002-September 2006 and a 12-month follow-up per patient.Setting: A large community hospital.Participants: Patients with symptoms of intermittent claudication due to an iliac or femoro-popliteal arterial lesion (293) who fulfilled the inclusion criteria (151) were recruited. Excluded were, for example, patients with lesions unsuitable for revascularization (iliac or femoropopliteal TASC-type D and some TASC type-B/C.Intervention: Participants were randomly assigned to endovascular revascularization (76 patients) or supervised hospital-based exercise (75 patients).Measurements: Mean improvement of health-related quality-of-life and functional capacity over a 12-month period, cumulative 12-month costs, and incremental costs per quality-adjusted life year (QALY) were assessed from the societal perspective.Results: In the endovascular revascularization group, 73% (55 patients) had iliac disease vs 27% (20 patients) femoral disease. Stents were used in 46/71 iliac lesions (34 patients) and in 20/40 femoral lesions (16 patients). In the supervised hospital-based exercise group, 68% (51 patients) had iliac disease vs 32% (24 patients) with femoral disease. There was a non-significant difference in the adjusted 6- and 12-month EuroQol, rating scale, and SF36-physical functioning values between the treatment groups. The gain in total mean QALYs accumulated during 12 months, adjusted for baseline values, was not statistically different between the groups (mean difference revascularization versus exercise 0.01; 99% CI −0.05, 0.07; P = .73). The total mean cumulative costs per patient was significantly higher in the revascularization group (mean difference €2318; 99% CI €2130, € 2506; P < .001) and the incremental cost per QALY was 231 800 €/QALY adjusted for the baseline variables. One-way sensitivity analysis demonstrated improved effectiveness after revascularization (mean difference 0.03; CI 0.02, 0.05; P < .001), making the incremental costs 75 208 €/QALY.Conclusion: In conclusion, there was no significant difference in effectiveness between endovascular revascularization compared to supervised hospital-based exercise during 12-months follow-up, any gains with endovascular revascularization found were non-significant, and endovascular revascularization costs more than the generally accepted threshold willingness-to-pay value, which favors exercise.

A percutaneous arterial closure protocol can decrease complications after endovascular interventions in vascular surgery patients

Philip P. Goodney, Robert W. Chang, Jack L. Cronenwett — 2008-12-01

Objective: Complications following percutaneous femoral access are a significant source of morbidity and cost in patients undergoing peripheral vascular interventions. Our purpose in this study is to determine if access complications could be reduced by the use of a standardized protocol.Methods: We studied prospectively 210 consecutive patients in our vascular surgery practice undergoing peripheral arterial interventions via percutaneous retrograde femoral access. First, we prospectively collected data to determine current outcomes during a 4-month observation phase. Based on these experiences, we designed and implemented a uniform arterial closure protocol, with closure device use guided by sheath size, arterial calcification, and previous groin scarring. Our main outcome measures were major complications (need for operation) or minor complications (access site bleeding or hematoma). Outcomes were compared between the two phases using chi-squared analysis and analysis of variance (ANOVA).Results: In the observation phase, 119 patients underwent 140 arterial punctures, and in the postprotocol phase, we performed 112 punctures in 91 patients. Between the observation and postprotocol phases, patient demographics were similar; average sheath size was unchanged (sheaths over 6F 6% vs 8%, respectively, P = .55), and percentage of patients receiving heparin did not change significantly (76% vs, 86%, P = .08). No major complications occurred in either the observation or the postprotocol phases. While 24 minor complications occurred in the observation phase, only seven minor complications occurred in the postprotocol phase (17% vs 7%, P < .02). Closure device use decreased with protocol implementation (57% to 32%, P < .01), but closure device failures also decreased from 23% to 7% (P < .01).Conclusions: Process improvement, achieved by instituting a standardized percutaneous arterial closure protocol based on selective closure device use guided by sheath size, arterial calcification, and previous access scarring. Implementation of our protocol resulted in a decrease in the incidence of minor complications at the access site and refined patient selection for closure device use.

Cost per day of patency: Understanding the impact of patency and reintervention in a sustainable model of healthcare

2008-12-01

Background: Healthcare resource utilization is an understudied aspect of vascular surgery. Initial cost of a given procedure is not an accurate reflection of resource utilization because it does not account for procedural durability and efficacy. Herein we describe an amortized cost model that accounts for procedural costs, durability, and re-intervention costs.Methods: A cost model was developed using patency data endpoints and total hospital costs (direct and indirect) associated with an inital revascularization and subsequent re-interventions. This model was applied to a retrospective database of femoropopliteal reconstructions. One hundred and eighty-three open cases were compared with 198 endovascular cases; and the endpoints of initial cost, amortized cost at 12 months, and assisted patency were examined.Results: The open and endovascular cases were not statistically different with respect to indication, patient co-morbid profiles, or post-procedural pharmacotherapy. Primary assisted patency was better in the open revascularization group at 12 months (78% versus 66%, P < .01). There was a statistically significant higher initial cost for open reconstruction when compared with endovascular ($12,389 ± $408 versus $6,739 ± $206, P < .001). However, at 12 months post-procedure, the initial cost benefit was lost for endovascular patients ($229 ± $106 versus $185 ± $124, P = .71). There was, however, a trend for endovascular cost savings in claudicants, though this did not reach significance ($259 ± $189 versus $86 ± $52, P = .31). For patients with critical limb ischemia, renal dysfunction, and end stage renal disease, the trend favored open surgery.Conclusions: An amortized cost model provides insight into the healthcare resource utilization associated with a particular revascularization and assistive procedures. The initial cost savings of endovascular therapies are not sustained over time. Cost-savings trends were noted, however, longer follow-up is required to see if these will reach statistical significance.

Altered fibrin clot structure and function in the healthy first-degree relatives of subjects with intermittent claudication

2008-12-01

Objective: Studies report clustering of cardiovascular risk factors and increased cardiovascular events in healthy first-degree relatives (FDR) of subjects with intermittent claudication (IC). Family history is an independent risk factor in coronary artery disease but the role of genetic factors is undefined in peripheral arterial disease. The fibrin clot is the final product of the atherothrombotic process and is subject to genetic influence. We proposed that healthy male FDR of subjects with IC possess abnormalities in their fibrin clots.Methods: This was a case-control family study. The FDR were recruited from claudicants attending vascular surgery out-patient clinics with the control subjects being recruited from the local primary care register. A total of 106 white European male FDR of male subjects with IC were age matched with 107 white European male control subjects from an identical geographic area. The control subjects had no FDR with a history of symptomatic cardiovascular disease, and subjects from both groups were free from a personal history of symptomatic cardiovascular disease or diabetes mellitus. Ex vivo assays for fibrin clot permeation, fiber thickness, factor XIII cross-linking activity, and fibrinolysis were performed on the plasma of the above subjects. In addition, linear regression analysis was undertaken to determine factors associated with clot parameters.Results: For controls and FDR, respectively, fiber thickness by turbidity was 0.75 (0.67-0.93) vs 0.86 (0.75-0.98) (P < .001), and FXIII cross-linking activity was 105% (87-141) vs 133% (103-155) (P < .001). On confocal microscopy, fibers measured 315.8 (307.0-324.6) vs 405.1 (397.6-412.6) nm (P < .001), and lysis front velocity was 12.66 (6.38-18.94) vs 4.83 (2.50-7.17), μm/min (P = .018). Linear regression analysis revealed cholesterol was associated with changes in certain clot parameters.Conclusion: The healthy FDR of subjects with IC produce clots which have thicker fibers, increased cross-linking, and resistance to fibrinolysis when compared to controls. This supports the potential genetic basis of peripheral arterial disease and highlights that cholesterol may contribute to this abnormal structure. This suggests that the FDR of subjects with IC, an apparently healthy sub-group of the population, have an elevated cardiovascular risk associated with abnormalities in their clot structure.Clinical Relevance: This study furthers our understanding of the pathophysiology of peripheral arterial disease, and is supported by our previous work on abnormalities in fibrin clot structure in the formation and progression of coronary artery disease. The study highlights the possible contribution of familial factors through transmission of an abnormal clot structure to the development of symptomatic cardiovascular disease. Most importantly, this work identifies the apparently healthy FDR group of the population as potentially at high cardiovascular risk and raises the question regarding the need for primary prevention in this group.

Preprocedural neutrophil count predicts outcome in patients with advanced peripheral vascular disease undergoing percutaneous transluminal angioplasty

Iqbal S. Toor, Rumi J. Jaumdally, Mark S. Moss, Suresh B. Babu — 2008-12-01

Background: The neutrophil count has been associated with adverse cardiovascular events after percutaneous coronary intervention. There are limited data on risk stratification of patients with advanced peripheral vascular disease (PVD) using white blood cell (WBC) subtypes. This study assessed the association of total and differential WBC counts with adverse outcome in patients with advanced PVD undergoing percutaneous transluminal angioplasty (PTA).Methods: In a retrospective cohort study, consecutive de novo procedures were analyzed for patients with Rutherford category 4 or 5 PVD who underwent successful nonemergency PTA. Cardiovascular risk factors, baseline total and differential WBC counts, and angiographic data were recorded. Primary outcome was a composite of events of target vessel revascularization (repeat PTA or vascular bypass operation) or lower limb amputation.Results: A total of 101 patients were studied. Their mean age was 76 ± 10 years, 54% had diabetes mellitus, 68% were hypertensive, and 12% had had previous myocardial infarction. We observed 29 events during a median period of 14 months (interquartile range, 4-26). Cox regression analysis found diabetes mellitus (odds ratio [OR], 4.67; 95% confidence interval [CI], 1.35-16.14; P = .02), Rutherford category 5 (OR, 4.18; 95% CI, 1.06-16.51; P = .04), poor tibial runoff (OR, 4.42; 95% CI, 1.16-16.82; P = .03), and preprocedural neutrophil count in the third tertile (OR, 10.77; 95% CI, 2.19-52.91; P = .003) were independent predictors of outcome.Conclusions: The results suggest that the preprocedural neutrophil count could be used in global risk factor assessment of patients with advanced PVD who are being considered for PTA. The neutrophil count may reflect the burden of atherosclerosis and tissue damage, and so could identify patients who need more aggressive intervention for advanced PVD.

Integrity of venoarteriolar reflex determines level of microvascular skin flow enhancement with intermittent pneumatic compression

2008-12-01

Objective: To investigate whether intermittent pneumatic compression (IPC) augments skin blood flow through transient suspension of local vasoregulation, the veno-arteriolar response (VAR), in healthy controls and in patients with peripheral arterial disease (PAD).Methods: Nineteen healthy limbs and twenty-two limbs with PAD were examined. To assess VAR, skin blood flow (SBF) was measured using laser Doppler fluxmetry in the horizontal and sitting positions and was defined as percentage change with postural alteration [(horizontal SBF − sitting SBF)/horizontal SBF × 100]. On IPC application to the foot, the calf, or both, SBF was measured with laser Doppler fluxmetry, the probe being attached to the pulp of the big toe.Results: Baseline VAR was higher in the controls 63.8 ± 6.4% than in patients with PAD (31.7 ± 13.4%, P = .0162). In both groups SBF was significantly higher with IPC than at rest (P < .0001). A higher percentage increase with IPC was demonstrated in the controls (242 ± 85% to 788 ± 318%) than in subjects with PAD, for each one of the three different IPC modes investigated (98 ± 33% to 275 ± 72%) with IPC was demonstrated. The SBF enhancement with IPC correlated with VAR for all three compression modes (r = 0.58, P = .002 for calf compression, r = 0.65, P < .0001 for foot compression alone, and r = 0.64, P = .0002 for combined foot and calf compression).Conclusion: The integrity of the veno-arteriolar response correlates with the level of skin blood flow augmentation generated with intermittent pneumatic compression, indicating that this may be associated with a transient suspension of the autoregulatory vasoconstriction both in healthy controls and in patients with PAD.

Incidence of ipsilateral postoperative deep venous thrombosis in the amputated lower extremity of patients with peripheral obstructive arterial disease

2008-12-01

Objective: Patients undergoing amputation of the lower limb due to peripheral arterial disease (PAD) are at risk of developing deep venous thrombosis (DVT). Few studies in the research literature report the incidence of DVT during the early postoperative period or the risk factors for the development of DVT in the amputation stump. This prospective study evaluated the incidence of DVT during the first 35 postoperative days in patients who had undergone amputation of the lower extremity due to PAD and its relation to comorbidities and death.Methods: Between September 2004 and March 2006, 56 patients (29 men), with a mean age of 67.25 years, underwent 62 amputations, comprising 36 below knee amputations (BKA) and 26 above knee amputations (AKA). Echo-Doppler scanning was performed preoperatively and on postoperative days 7 and 31 (approximately). All patients received acetylsalicylic acid (100 mg daily) preoperatively and postoperatively, but none received prophylactic anticoagulation.Results: DVT occurred in 25.8% of extremities with amputations (10 AKA and 6 BKA). The cumulative incidence in the 35-day postoperative period was 28% (Kaplan-Meier). There was a significant difference (P = .04) in the incidence of DVT between AKA (37.5%) and BKA (21.2%). Age ≥70 years (48.9% vs 16.8%, P = .021) was also a risk factor for DVT in the univariate analysis. Of the 16 cases, 14 (87.5%) were diagnosed during outpatient care. The time to discharge after amputation was averaged 6.11 days in-hospital stay (range, 1-56 days). One symptomatic nonfatal pulmonary embolism occurred in a patient already diagnosed with DVT. There was no relation between other comorbidities and DVT. The multivariate analysis showed no association between risk factors and the occurrence of DVT in the amputated extremity. DVT ipsilateral to the amputation did not influence the mortality rate (9.7%).Conclusion: The incidence of DVT in the early postoperative period (≤35 days) was elevated principally in patients aged ≥70 years and for AKA. Patients with PAD who have recently undergone major amputations should be considered at high risk for DVT, even after hospital discharge. Given the high rate of postoperative DVT observed in this study, we now recommend prophylactic anticoagulation for these patients, but further study is needed to determine the optimal duration and efficacy of this treatment.

Use of vacuum-assisted closure (VAC) therapy in treating lymphatic complications after vascular procedures: New approach for lymphoceles

2008-12-01

Objective: Lymphatic complications, such as lymphocutaneous fistula (LF) and lymphocele, are relatively uncommon after vascular procedures, but their treatment represents a serious challenge. Vacuum assisted closure (VAC) therapy has been reported to be an effective therapeutic option for LF, but the effectiveness of VAC therapy for lymphoceles is unclear.Methods: For LF, we apply the VAC directly to the skin defect after extending it to achieve a clean wound of at least one inch in length. To treat lymphocele, we convert the lymphocele to a LF in a sterile fashion by making a one inch incision in the overlying skin and applying the VAC. The setting was a community teaching hospital. We used 10 patients that we treated with VAC therapy for LF (n = 4) and lymphoceles (n = 6).Results: Duration of in-patient stay, duration of in-patient VAC treatment, duration of out-patient VAC treatment, total duration of VAC treatment. The median duration of in-patient stay was 4 (range, 0-18) days, the median duration of in-patient VAC treatment was 1 (range, 0-5) days, the median duration of out-patient VAC treatment was 16 (range, 7-28) days), and the median total duration of VAC therapy was 18 (range, 13-29) days. Successful wound healing was achieved in all patients with no recurrence after VAC removal. VAC therapy for treatment of both LFs and lymphoceles resulted in early control of drainage, rapid wound closure, and short hospital stays.Conclusion: Our results suggest that VAC therapy is a convenient and effective therapeutic option for both LFs and lymphoceles.

Angioplasty with stent graft versus bare stent for recurrent cephalic arch stenosis in autogenous arteriovenous access for hemodialysis: A prospective randomized clinical trial

2008-12-01

Background: Early recurrent stenosis of the cephalic arch in autogenous arteriovenous access for hemodialysis is a common problem that requires stenting to prevent thrombosis. Because the results of stenting are unsatisfactory, we compared the efficacy of stent grafts with bare stents in these patients.Methods: All patients who presented with recurrent cephalic arch stenosis >50% within 3 months of successful balloon angioplasty were randomized to have angioplasty and stenting with either a bare nitinol stent or a stent graft. Outcome was assessed by angiography 3 months later. Restenosis was defined as >50% narrowing of the stent lumen or of the vessel margin up to 0.5 cm adjacent to the stent. There were no exclusions.Results: This report includes data on the outcome of 25 consecutive patients with recurrent cephalic arch stenosis who were treated from April to August 2006. At 3 months, three patients had died and one had undergone a renal transplant. The 21 patients who had angiography at 3 months had patent stents. Restenosis rates were seven of 10 (70%) in the bare stent group and two of 11 (18%) in the stent graft group (P = .024). Life-table analysis at 3 and 6 months showed that primary patency was 82% in the stent graft group and 39% in the bare stent group. One-year primary patency was 32% in the stent graft group and 0% in the bare stent group (P = .0023). During a mean follow-up of 13.7 months, nine patients died, four in the bare stent group and five in the stent graft group. Two patients in the stent graft group had received a renal transplant. The number of interventions per patient-year was 1.9 in the bare stent group and 0.9 in the stent graft group (P = .02).Conclusions: The use of stent grafts in angioplasty for recurrent cephalic arch stenosis significantly improved short-term restenosis rates and long-term patency compared with the use of bare stents. The significant improvement that emerged during the study caused accrual of patients to be halted for ethical reasons. This study altered our usage of stents for venous stenoses in arteriovenous accesses by eliminating bare nitinol stents in favor of stent grafts.

The quantitative benefit of isolated, segmental, pharmacomechanical thrombolysis (ISPMT) for iliofemoral venous thrombosis

2008-12-01

Background: Early thrombus removal in patients with iliofemoral deep venous thrombosis (IFDVT) reduces postthrombotic morbidity. Preserving valve function and relieving venous obstruction prevents deterioration of quality of life and loss of economic potential. The preferred method for treating IFDVT is catheter-directed thrombolysis (CDT). Recently, isolated segmental pharmacomechanical thrombolysis (ISPMT) has emerged as a treatment option for patients with extensive IFDVT. The purpose of our study is to determine whether there are advantages to using ISPMT as the primary treatment for patients with iliofemoral IFDVT and, if so, to quantify those advantages relative to CDT.Methods: Forty-three patients with IFDVT were treated with percutaneous CDT between May 2003 and June 2007. Twenty-one patients (27 limbs) were treated with CDT and 22 patients (25 limbs) were treated with ISPMT ± CDT. Demographics, extent of thrombus, procedural details, and thrombus resolution were recorded.Results: Treatment time (55.4 vs 23.4 hours; P < .0001) and dose of rt-PA (59.3 vs 33.4 mg; P = .0009) were decreased and overall lytic success (60% vs 80%; P = .0016) increased with ISPMT. Adjunctive venoplasty and stenting, complications, hospital length-of-stay (LOS), and intensive care unit LOS were similar between groups.Conclusion: ISPMT offers more effective thrombus removal in less time and with a reduced dose of thrombolytic agent. However, decreased treatment time did not translate into decreased hospital or ICU stay. Longer-term follow-up is required to determine whether improved thrombus resolution translates to better functional outcome and reduced postthrombotic morbidity.

Endovenous laser ablation: Venous outcomes and thrombotic complications are independent of the presence of deep venous insufficiency

2008-12-01

Objective: We hypothesize that endovenous laser ablation (EVA) therapy is equally successful in improving venous insufficiency symptoms in patients with or without deep venous insufficiency (DVI).Methods: From January 2005 through August 2007, EVA of the great saphenous vein (GSV) was attempted in 364 patients (460 limbs) with symptomatic GSV reflux. The GSV was successfully cannulated and obliterated in all but 17 limbs. EVA was performed alone in 308 limbs (69.5%) and with phlebectomy or perforator ligation (EVAP) in 135 limbs (30.5%). Venous clinical severity scores (VCSS) were recorded preoperatively and at 30, 90, 180, and 360 days postoperatively. Patients were classified as those with or without DVI based on duplex imaging valve closure times at the common femoral vein (CFV) and popliteal vein (PV). In a subset of 181 patients undergoing EVA therapy in the operating room, perioperative thrombosis prophylaxis was administered based on a risk-stratification protocol. Patients were assessed with direct end points (VCSS) and indirect end points (vein occlusion rates).Results: Successful performance of EVA led to complete saphenous vein ablation in 99.8% at 1 month and 95.9% at 1 year. Median VCSS preoperatively was 6 (interquartile range, 5-8), generally decreasing over all time points to 4 (interquartile range, 2-5) beyond 360 days (P < .001). Male gender was independently associated with greater improvement in scores with time (P = .019). Changes in VCSS and duration of vessel occlusion were equivalent regardless of DVI for both isolated EVA and EVAP. For EVAP, the true deep venous thrombosis (DVT) rate was 2.2%, whereas for isolated EVA, the rate was 0% (P = .028); the rate of saphenofemoral thrombus extension was 5.9% for EVAP vs 7.8% for isolated EVA (P = .554). The use of risk-adjusted heparin prophylaxis in patients undergoing EVAP did not have a significant effect on thrombotic complications. There were no differences in true DVT, thrombus extension, or superficial thrombophlebitis between patients with or without DVI. Performance of concomitant phlebectomy, DVI, gender, and age had no effect on the duration of vessel occlusion.Conclusion: EVA produces successful ablation and is associated with sustained improvement in VCSS. These outcomes are independent of the presence of DVI. Finally, the use of a risk-adjusted thrombosis prevention protocol had no effect on the rate of superficial thrombus extension from EVA or EVAP in patients undergoing general anesthesia.

Cellular and molecular mechanism regulating blood flow recovery in acute versus gradual femoral artery occlusion are distinct in the mouse

2008-12-01

Background: Most current animal models of hindlimb ischemia use acute arterial occlusion that does not accurately reflect the pathogenesis of gradual arterial occlusion in humans. We, therefore, developed the first mouse model of gradual arterial occlusion and tested the hypothesis that the mechanisms regulating blood flow recovery are critically dependent on the rate of arterial occlusion.Methods: Gradual arterial occlusion was induced by placing ameroid constrictors on the proximal and distal left femoral artery, and ligating the femoral arterial branches (n = 36). Acute arterial occlusion was accomplished by excising the left femoral artery (n = 36). The blood flow recovery was studied by laser Doppler imaging. Differential gene expression between these two models was assessed by quantitative real-time polymerase chain reactions (PCR). Inflammatory and progenitor cells recruitment were determined by immunohistochemistry.Results: We found that hypoxia-related genes increased significantly in the calf, but not in the thigh, after gradual and acute femoral arterial occlusion (P < .05). Shear-stress dependent genes and inflammatory genes were upregulated immediately in the thigh only after acute femoral arterial occlusion (P < .05). These differences in gene expression were consistent with increased SDF-1α expression, recruitment of macrophages and hemangiocytes, and higher blood flow recovery after acute arterial occlusion than after gradual arterial occlusion (P < .05).Conclusion: This is the first study to show the mechanisms that regulate blood flow recovery are critically dependent on the rate of arterial occlusion. This novel model of gradual arterial occlusion may more closely resemble the human diseases, and may provide more accurate mechanistic insights for creating novel molecular therapies.

Experimental study of hemodynamics in procedures to treat access-related ischemia

Juergen Zanow, Ulf Krueger, Peer Reddemann, Hans Scholz — 2008-12-01

Objective: This experimental study investigated the hemodynamic effect of corrective procedures for arteriovenous access–related ischemia in pulsatile flow.Methods: Silicone models of an emulated tapered and bifurcated arterial tree of the upper arm and forearm were integrated into a pulsatile flow circuit. The model allowed the study of hemodynamics of simulated arteriovenous fistulas, including collateral circulation, as well as the study of different simulated procedures to improve distal hypoperfusion. Flow rates and arterial pressure were measured simultaneously during simulation of corrective procedures and correlated to hemodynamic values of uncorrected ischemia.Results: It was demonstrated that the more proximally localized an arteriovenous anastomosis is, the higher the distal arterial pressure will be at any given fistula flow. Reduction of the fistula flow resulted in a significant improvement of distal perfusion. Ligation of the artery distal to the arteriovenous fistula to prevent retrograde flow increased the distal perfusion only slightly in simulated ischemia. In contrast, the simulated corrective procedures of distal revascularization interval ligation and proximalization of arterial inflow resulted in a significant improvement. The most significant improvement of distal perfusion was observed with the simulated proximalization technique, whereas the effect of distal revascularization technique was less pronounced at higher fistula flow. Arterial ligation after distal revascularization increased the distal pressure only by 10%.Conclusion: A more centrally localized arteriovenous anastomosis and a reduction of fistula flow significantly increase distal perfusion. The procedure of proximalization of arterial inflow is at least equivalent to the distal revascularization interval ligation technique for the correction of distal ischemia, but does not sacrifice a patent axial artery. The moderate effect of interval ligation of the latter technique should be evaluated by further intraoperative measurements.Clinical Relevance: Our model examines the hemodynamics of different corrective procedures for access-related distal ischemia. Results support the use of banding and proximalization of arteriovenous anastomosis to improve distal perfusion. The experimental data demonstrate a marginal additional improvement of distal revascularization technique by subsequent arterial ligation. That poses the question about the necessity to ligate an axial artery.

Adventitial delivery of platelet-derived endothelial cell growth factor gene prevented intimal hyperplasia of vein graft

2008-12-01

Background: Platelet-derived endothelial cell growth factor (PD-ECGF), also known as thymidine phosphorylase (TP) reportedly inhibits vascular smooth muscle cells (VSMCs) migration and proliferation. We hypothesized that adventitial administration of the PD-ECGF/TP gene will suppress intimal hyperplasia and prevent vein graft failure.Methods: The study used 68 female rabbits. Rabbit jugular vein was autogenously transplanted into carotid artery with a cuff anastomotic technique. To define vascular wall gene transfer efficiency, poloxamer hydrogel (20%) containing plasmid vector encoding the LacZ gene and different concentrations of trypsin (0%, 0.1%, 0.25%, and 0.5%, n = 5 for each group) was applied to the adventitia of the vein graft. Gene transfer efficiency was evaluated 7 days later by X-gal staining. An additional 48 rabbits received poloxamer hydrogel (20%) containing 0.25% trypsin and the human PD-ECGF/TP gene, LacZ gene, or saline. Intima thickness was evaluated at 2 and 8 weeks after grafting (n = 8 for each group at each time point). Transgene expression was examined by reverse transcriptase-polymerase chain reaction, immunoblotting assay, and immunohistochemical staining. Immunohistochemical staining was also used to determine VSMC proliferation, heme oxygenase-1 expression, and macrophage infiltration.Results: Incorporation of trypsin into the poloxamer hydrogel significantly increased vessel wall gene transfer. Trypsin at 0.25% and 0.5% resulted in higher gene transfer at the same level without effecting intimal hyperplasia and inflammation; thus, trypsin at 0.25% concentration was used for subsequent experiments. Compared with the LacZ and saline groups, grafts receiving the PD-ECGF/TP gene significantly reduced intimal thickness at 2 and 8 weeks after treatment. The ratio of proliferative VSMC was lower in PD-ECGF/TP treated grafts. Histologic examination of the PD-ECGF/TP transgene grafts demonstrated high expression of heme oxygenase-1, which has been reported to inhibit VSMC proliferation, suggesting that heme oxygenase-1 may be important in the inhibition effect of PD-ECGF/TP on VSMC. No neoplastic or morphologic changes were found in the remote organs.Conclusions: A safe and highly efficient gene transfer method was developed by using poloxamer hydrogel and a low concentration of trypsin. Neointimal hyperplasia was significantly reduced by adventitial application of the PD-ECGF/TP gene to the vein graft. Our data suggest that adventitial delivery of the PD-ECGF/TP gene after grafting may be promising method for preventing vein graft failure.Clinical Relevance: Vein graft failure caused by intimal hyperplasia limits the benefits of vein grafting. Various treatments have been examined to reduce intimal thickness, but a standard clinical treatment has not yet been established. We report the inhibitory effect of the gene expressing platelet-derived endothelial cell growth factor/thymidine phosphorylase (PDEGF/TP) on the development of vein graft intimal thickness with a novel hydrogel painting method. This could lead to a new therapeutic strategy for prevention of vein graft failure, and is easy to perform during bypass surgery.

Deep vein thrombosis resolution is impaired in diet-induced type 2 diabetic mice

Fatiha Bouzeghrane, Xiaochun Zhang, Guylaine Gevry, Jean Raymond — 2008-12-01

Objective: Type 2 diabetes mellitus results in a procoagulant and thrombogenic state that could predispose diabetic individuals to develop venous thrombosis. We sought to determine whether diet-induced type 2 diabetes mellitus affects deep venous thrombosis (DVT) resolution in a murine model.Methods: C57Bl/6 mice were fed a low-fat or a high-fat diet (n = 10) for 10 weeks, after which DVT was created in the inferior vena cava (IVC) by a combination of low flow and endothelial damage. The IVC and thrombus were harvested at 1 and 2 weeks. Thrombus resolution and neovascularization were investigated through transfemoral angiography (n = 10), thrombus size (n = 4) and weight (n = 10), and nitric oxide synthase 3 immunoquantification (n = 4). Macrophage content was assessed by CD68 immunoreactivity (n = 4). The fibrinolytic system (urokinase plasminogen activator [uPA] and plasminogen activator inhibitor-1 [PAI-1]) was analyzed by Western immunoblotting (n = 6) and immunohistochemistry (n = 4). Total collagen was stained by Sirius red. Matrix metalloproteinases (MMP)-2 and MMP-9 activities were evaluated by zymography and their expressions by Western immunoblotting (n = 6) and immunohistochemistry (n = 4).Results: Diabetic mice had significantly larger and heavier thrombi at 1 and 2 weeks (P < .05), threefold less neovascularization (P < .05), and 35-fold increase in macrophage content (P < .01), than control mice 2 weeks after surgery. IVC recanalization was documented in 90% of 2-week control mice and in 10% of 2-week diabetic mice (P < .01). Increased vein wall collagen and less uPA and more PAI-1 expressions with a decreased uPA/PAI-1 ratio (31%, P < .01) were documented at 2 weeks in diabetic mice. MMP-2 and MMP-9 activities and expressions were significantly increased in diabetic mice at 1 and 2 weeks (P < .05) compared with control mice.Conclusion: Diet-induced type 2 diabetes may impair DVT resolution through altered inflammatory, fibrinolytic, and MMP responses.Clinical Relevance: Little is known about the risk of venous thromboembolism in patients with type 2 diabetes mellitus, which accounts for 95% of diabetes mellitus. Deep venous thrombosis and pulmonary embolism generating post-thrombotic syndrome remain significant clinical problems, affecting approximately 200,000 to 300,000 patients per year. The current obese/diabetic mouse model and the mouse model of stasis thrombus resolution provide useful approaches for determining the effect and understanding the basic biologic mechanisms of type 2 diabetes mellitus on deep venous thrombosis resolution, as well as serving as valuable tools for evaluating therapeutic options.

Spontaneous re-expansion of a collapsed thoracic endoprosthesis: Case report

Alejandro Pontón, Iván García, Elena Arnáiz, José M. Bernal — 2008-12-01

A 43-year-old woman with a type B aortic dissection underwent insertion of a Zenith stent graft (Cook Inc, Bloomington, Ind). Chest pain developed 36 hours after the procedure. A computed tomography scan showed reopening of the false proximal lumen and almost complete device collapse. Because of hemodynamic stability and absence of signs of malperfusion, the patient was treated conservatively. A control computed tomography scan 7 days later showed full re-expansion of the endoprosthesis. This case illustrates that in extremely rare cases, spontaneous reexpansion of a collapsed thoracic endoprosthesis can occur after conservative management.

Hypoplasia and fibromuscular dysplasia of infrarenal abdominal aorta with downstream aneurysm: Case report and review of the literature

Attilio Odero, Antonio Bozzani, Vittorio Arici, Manuela Agozzino — 2008-12-01

Fibromuscular dysplasia represents one of the more common types of arterial fibrodysplasia, a heterogeneous group of nonatherosclerotic vascular occlusive and aneurysmal diseases. This disorder mainly affects renal and cerebral arteries, and less frequently, arm, leg, and visceral arteries. Exceptionally, it has been described in the abdominal aorta. Aortic hypoplasia is a tubular narrowing of a long segment of the aorta and is a rare congenital defect, different from coarctation, which is a focal stricture. We present the first case, to our knowledge, of an elderly man with infrarenal aortic fibromuscular dysplasia associated with aortic hypoplasia, without involvement of renal arteries, and contiguous aortoiliac aneurysm.

A staged replacement of the entire aorta from the ascending arch to the hypogastric arteries using a hybrid approach

Juan Carlos Jimenez, Wesley S. Moore — 2008-12-01

Combined open and endovascular hybrid procedures can be used to treat complex aortic pathology. This article reports a five-stage hybrid repair for a complex thoracoabdominal aneurysm with dissection in a 57-year-old man. To our knowledge, this is the first reported case of replacement and exclusion of the entire native human aorta from the root to the iliac bifurcations using a combined open and endovascular approach without neurologic complication. Bilateral hypogastric and femoral circulation was preserved. Aggressive spinal protective measures, including spinal drainage, motor-evoked potentials, and prevention of intraoperative and perioperative hypotension, were used during this staged approach.

Endovascular management of a large post-traumatic iliac arteriovenous fistula: Utilization of a septal occlusion device

Curtis A. Anderson, Robert K. Strumpf, Edward B. Diethrich — 2008-12-01

We describe the management of a large iliac arteriovenous fistula in a 48-year-old patient presenting with heart failure and pulmonary hypertension. The presumptive etiology was a left-lower back stab wound approximately 20 years earlier. A large communication between the left internal iliac artery and the left internal iliac vein was successfully treated with a septal occlusion device.

Reconstruction of occluded thoracic duct for treatment of chylopericardium: A novel surgical therapy

2008-12-01

Chylopericardium is an uncommon disease predominantly caused by trauma. Prolonged chyle depletion may result in nutritional, metabolic, and immunologic deficiencies due to loss of essential proteins, immunoglobulins, fat, vitamins, electrolytes, and water. Medical treatment includes a low-fat diet with medium-chain triglyceride restriction, cardiac support, diuretic medications, and drainage of the pericardial effusion. Conventional surgical therapy consists of pericardial fenestration and thoracic duct ligation. We report a case of massive secondary chylous pericardial effusion successfully treated with microsurgical lymphovenous anastomosis, reconnecting the occluded thoracic duct to the internal jugular vein. This case highlights features and management strategies of this perplexing clinical condition.

An unusual presentation of pedunculated thrombus in the distal arch of the aorta after splenectomy for B-cell lymphoma

2008-12-01

A 59-year-old woman who was asymptomatic after a splenectomy for B-cell lymphoma was found to have a pedunculated mass filling 50% of the aortic lumen within the distal aortic arch on a routine follow-up computed tomographic scan of the chest (A/, and B). She was referred to us with a differential diagnosis of tumor originating from the aortic wall. On transesophageal echocardiogram it seemed to be a solid mass rather than a floating thrombus. With suspicion of malignancy, it was decided to remove the mass surgically.