Journal of Vascular Surgery
Volume 48, Issue 1 , Pages 10-18, July 2008

Contemporary results of open repair of ruptured abdominal aortoiliac aneurysms: Effect of surgeon volume on mortality

Division of Vascular Surgery, University of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, Pa.

Received 9 November 2007; accepted 26 February 2008. published online 03 June 2008.

Article Outline

Objective

The purpose of this study is to evaluate contemporary results of ruptured aortoiliac aneurysms (RAAA) and identify the role of surgeons' annual aortic volume and other prognostic indicators for early outcome.

Methods

A retrospective review identified 213 consecutive patients who presented with an atherosclerotic RAAA without thoracic extension over 6.5 years ending in June 2007. Excluded were 31 ruptures treated by endovascular repair (EVAR) or following previous EVAR, also excluded were two chronic asymptomatic hemodynamically stable ruptures. Ten patients were not treated due to either patient's refusal or prohibitive surgical risk. Demographic, preoperative, intraoperative, and postoperative variables were collected. Log rank test and Cox proportional hazard model analyses were utilized to identify factors contributing to mortality and morbidity in these patients. Survival rates were estimated by Kaplan-Meier method.

Results

One hundred thirty-one males and 39 females with a mean age of 74.5 ± 8.1 years underwent consecutive RAAA repairs. The operative mortality rate was 38.2% (65/170), including 29 intraoperative deaths. Using multivariate analysis, surgeon's average annual AAA volume (<20/y), advanced age, and postoperative intestinal ischemia were independent predictors of perioperative deaths. Shock on presentation, preoperative cardiopulmonary resuscitation or free rupture were not. High-volume surgeons (>20 average annual AAA cases/y) had a higher 30-day survival rates (78.4% vs 57.9%, P = .024). Octogenarians had a lower 30-day survival rate of 49.0% vs 70.5% (P = .012). Patients who developed postoperative intestinal ischemia had a lower 30-day survival rate compared with patients without (48.1% vs 15.3%, P = .002). Increased intraoperative fluid and blood product usage was associated with bowel ischemia (P < .05).

Conclusions

RAAA remains a highly lethal problem. The improved early outcomes of surgeons with high-volume AAA have strong implications for training, emergency staffing needs and alternative treatment strategies.

 

While elective open repairs of abdominal aortic aneurysm (AAA) can be performed safely with a mortality rate of about 5%,1, 2, 3 emergent repairs of ruptured AAA (RAAA) continue to be associated with significantly worse outcomes. Although some studies have shown improvement in operative mortality over time,3, 4, 5 most series still report staggering mortality rates for open repairs of RAAA ranging from 40% to 50%.1, 3, 4, 5, 6, 7, 8, 9

Endovascular repair (EVAR) of RAAA has evolved as an alternate therapeutic option for selected patients with suitable anatomy to leverage its minimally invasive approach.10, 11, 12 However, most series still report mortality rates in excess of 30%, including the National Inpatient Sampling (NIS) and Medicare database.2, 3, 13, 14 The only randomized controlled trial failed to show survival benefit with EVAR compared with conventional open repair.15 As such, improving outcomes with open surgical repair remains an important aspect of managing RAAA. Regionalization of care to “centers of excellence” has been advocated by several investigators to improve outcomes.16, 17, 18 However, review of surgical results from these centers has not revealed a marked difference in mortality rates compared with low-volume centers. Individual surgeons' volume has been identified as a significant factor contributing to improved results with elective procedures, but not as well with emergency repairs.7, 8, 19 The purpose of this study was to review contemporary results of open repair of RAAA in a high-volume tertiary referral center and identify the role of surgeon volume and other prognostic indicators on early patient outcome.

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Materials and methods 

A retrospective review of 213 patients presented with a RAAA without thoracic extension at the University of Pittsburgh Medical Center (UPMC) from January 2001 to June 2007 was performed. The diagnosis of rupture was confirmed by review of preoperative computed tomography (CT) findings and in all patients by a clear description of intraoperative visualization of blood outside the aneurysm wall, either in the retroperitoneum, mesentery, or into the peritoneal cavity for free ruptures. Patients who had prior EVAR of infrarenal AAA (eight patients) and those who underwent EVAR for their RAAA (23 patients) were excluded from the study. Also excluded were two patients with chronic ruptures who were asymptomatic and hemodynamically stable. Surgical repair was not performed in 10 patients due to prohibitive surgical risk or patient's refusal. The remaining 170 patients form the basis for this study. This study was approved by the Institutional Review Board of the University of Pittsburgh.

Baseline characteristics of patients and intraoperative and postoperative variables were documented. Major postoperative complications were recorded. Preoperative shock was defined as systolic blood pressure less than 80 mm Hg or a requirement for preoperative cardiopulmonary resuscitation (CPR). Postoperative renal insufficiency was defined as creatinine greater than 2.0 mg/dL.16 Operative mortality was defined as death within 30 days of operation or in-hospital death if later than 30 days. Surgical repairs were performed by 14 different vascular surgeons, who were either board certified or eligible, in the division of vascular surgery at UPMC during the study period. Three surgeons were classified as high-volume aortic surgeons with greater than or equal to 20 average annual elective open AAA cases over the study period. The criteria of 20 was chosen based on review of literature on definition of high volume vs low volume as it relates to AAA volume.20, 21 Clinical follow-up examination was complemented with review of medical records.

Continuous variables are summarized as mean and standard deviation, and categorical variables are summarized as counts and percentages. Baseline characteristics were compared using t test for continuous variables or χ2 test and Fisher exact test for categorical variables.

Statistical analysis 

Univariate analysis was used to assess demographic, clinical, procedural, and postoperative factors associated operative deaths (Table I). Cox proportional hazard model was then used for multivariate analysis to identify factors that were independently associated with operative mortality. Survival rates were calculated using Kaplan-Meier method. Kaplan-Meier curves are presented, and they are compared using log-rank test statistics, if appropriate. Analyses were performed with SAS, version 9.1 under the alpha level of 0.05 (SAS institute Inc, Cary, NC).

Table I. Baseline characteristics of patients undergoing repair of ruptured aortoiliac aneurysms
VariableAverage ± SD (n) or percentage (n)
Patient demographics
Age (y)74.5±8.0(170)
Female22.9(39/170)
History of COPD33.5(55/164)
History of CVA17.0(28/165)
History of CAD57.6(95/165)
History of diabetes mellitus15.8(26/165)
History of PVD20.6(34/165)
History of hypertension80.0(132/165)
History of CRF13.9(23/165)
History of hemodialysis0.6(1/161)
Current smoking35.4(57/161)
Preoperative characteristics
Any prior aortic reconstruction5.9(10/170)
Distance to hospital (miles)47.2±38.6(169)
ER to OR time (min)76±218(157)
Free rupture21.9(37/169)
Preoperative SBP <80 mm Hg53.6(89/166)
Preoperative CPR24.3(41/169)
Blood chemistry
Mean hemoglobin (g/dL)11.1±2.6(162)
Mean platelet207.5±81.6(158)
Intraoperative variables
RBC transfusion in units8±7(149)
FFP transfusion in units4±6(149)
Platelet transfusion in packs1±2(149)
Proximal aortic clamp site
Supraceliac48.8(83/170)
Supra-SMA5.9(1/170)
Suprarenal7.7(13/170)
Between the renals2.4(4/170)
Supraceliac clamp time10±17(137)
Suprarenal clamp time13±19(139)
Lowest blood pressure (mm Hg)
IMA reimplantation4.1(7/170)
Postoperative variables
Renal failure requiring hemodialysis21.1(36/170)
Myocardial infarction32.4(55/170)
Tracheostomy19.4(33/170)
Stroke7.7(13/170)
Intestinal ischemia15.9(27/170)
Failure to close abdomen15.3(26/170)

COPD, Chronic obstructive pulmonary disease; CVA, cerebrovascular accident; CAD, coronary artery disease; PVD, peripheral vascular disease; CRF, chronic renal failure; SBP, systolic blood pressure; OR, operating room; CPR, cardiopulmonary resuscitation; ER, emergency room; OR, operating room; RBC, red blood cells; IMA, inferior mesenteric artery; FFP, fresh frozen plasma.

Data are % (n) or mean ± D.

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Results 

The baseline characteristics of the patients in this study are detailed in Table I. There were 131 (77.1%) males and 39 (22.9%) females with a mean age of 74.5 ± 8.0 years. Most (84.1%) of these patients were transferred from referring hospitals; 11 patients were in-patients at the time of rupture. The mode of transportation at presentation was by air in 109 cases (64.1%) and by ground in 50 cases (29.4%). Thirty-seven patients (21.8%) presented with free ruptures. Aortocaval and aortoenteric fistulae were noted in two patients each. Nine patients presented with ruptured iliac aneurysms.

A midline transperitoneal approach was used in all but two patients. Control of the aorta was obtained primarily at the infrarenal portion in 69 patients (40.6%). The remainder had initial aortic control above the renal arteries, mostly at the supraceliac aorta (83 patients). The left renal vein was divided in 15 patients, a renal artery bypass grafting performed in three, and the inferior mesenteric artery reimplanted in seven. Excluding the intraoperative deaths, the mean operative time was 186 ± 92 minutes.

The operative mortality rate was 38.2% (65/170). Nearly half (29/65) of the deaths were intraoperative of which 19 occurred even before the graft could be implanted. Fifty-one of 170 patients underwent repairs by high-volume surgeon of whom 11 died, including four intraoperative deaths. The remaining 119 patients were operated on by low-volume surgeons; 54 deaths occurred of which 25 were intraoperative. Comparison of baseline characteristic between the two groups is listed in Table II. The only significant comorbidity difference noted was the higher prevalence of hypertension in patients operated on by low-volume surgeons. Patients treated by low-volume surgeons also tended to come from a greater distance (P = .05) and tended to require preoperative CPR (P = .06) more frequently. On the other hand, there were trends towards more free ruptures (P = .05) and more patients with chronic renal insufficiency for high-volume surgeons (P = .06).

Table II. Baseline characteristics of patients undergoing repair of ruptured aortoiliac aneurysms by surgeons' annual aortic volume
VariableHigh-volume surgeonsLow-volume surgeonsP value
Age (y)75.5±8.2(51)74.1±8.0(119).30
Female19.6(10/51)24.3(29/119).50
History of COPD37.3(19/51)31.9(36/113).50
History of CVA15.7(8/51)17.5(20/114).77
History of CAD51.0(26/51)60.5(69/114).25
History of diabetes mellitus19.6(10/51)14.0(16/114).36
History of PVOD21.6(11/51)20.2(23/114).84
History of hypertension66.7(34/51)86.0(98/114)<.01
History of CRF21.6(11/51)10.5(12/114).06
History of hemodialysis0.0(0/51)0.9(1/110).49
Current smoking36.7(18/49)34.8(39/112).82
Prior aortic reconstruction5.9(3/51)5.9(7/119)1.00
Preoperative characteristics
Distance to hospital (miles)38.2±33.2(51)51.0±40.3(118).05
Preop SBP < 80 mm Hg50.0(25/50)55.2(64/116).54
Preoperative CPR13.7(7/51)28.8(34/118).06
Free rupture31.4(16/51)17.8(21/118).05
Mean hemoglobin (g/dL)11.2±2.6(51)11.0±2.6(111).60
Mean platelet217.8±85.7(50)202.8±79.5(108).28
Intraoperative variables
OR fluid4046.3±1891.3(48)3573.7±1565.4(112).10
OR blood7.4±6.8(50)7.1±6.5(115).80
OR FFP4.4±6.8(50)3.7±4.9(114).53
Supraceliac clamp time10.6±13.9(48)10.3±18.4(101).92
Renal ischemia time12.7±19.3(48)14.2±20.0(100).66

COPD, Chronic obstructive pulmonary disease; CVA, cerebrovascular accident; CAD, coronary artery disease; PVOD, peripheral vascular occlusive disease; CRF, chronic renal failure; SBP, systolic blood pressure; OR, operating room; CPR, cardiopulmonary resuscitation; FFP, fresh frozen plasma.

Data are % (n) or mean ± D.

The multivariate analysis of operative mortality with Cox proportional hazard model revealed that surgeon's average annual AAA volume of less than 20, advanced patient age, and postoperative intestinal ischemia were independent predictors of perioperative deaths (Table III). The surgeons' average annual RAAA volume was not found to have an impact on the mortality rates (Fig 1). No correlation was noted between the number of years of experience (defined as number of years in practice at the time of particular operation and analyzed as a continuous variable) and the individual surgeon's mortality rates.

Table III. Factors associated with in-hospital mortality (Cox proportional hazard model)
VariableHazard ratio95% Confidence intervalP value
Surgeon's annual AAA volume ≥200.2800.093,0.841.023
Age1.0761.016,1.139.012
Intestinal ischemia4.3421.720,10.961.002

AAA, Abdominal aortic aneurysm.

Fig 2 depicts the individual surgeons' average annual elective aortic aneurysm volume and mortality rates. To account for yearly variation in surgeons' annual elective volume over the study period, average annual volume over the study period was used. No surgeon crossed from the low-volume category to the high-volume category at any time during the study period. High-volume surgeons had a lower 30-day mortality rate compared with low-volume surgeons (21.6% vs 42.1%, P = .024) (Fig 3). No significant differences were noted between these two groups with respect to intraoperative variables. Perioperative variables such as operative time, intraoperative blood product usage, amount of fluid administration, supraceliac clamp time, or renal ischemic time did not differ between the high- and low-volume surgeons.

Inferior mesenteric artery reimplantation was rare but performed more frequently by high-volume surgeons than low-volume surgeons (5/47 vs 2/94, P = .03). This was not found to be an independent predictor of bowel ischemia. The incidence of other complications such as intestinal ischemia, renal failure requiring hemodialysis, and pulmonary failure did not differ between the two surgeon groups, except for failure to close the abdomen at the completion of the procedure, which occurred more frequently with the low-volume surgeon group (Table IV). Failure to close abdomen was not found to be a predictor of death on multivariate analysis.

Table IV. Comparison of morbidity and mortality rates between surgeons with high and low open AAA volume
VariableHigh-volume surgeons (%)Low-volume surgeons (%)P value
Operative mortality21.645.4.024
Myocardial ischemia40.439.1.88
Renal failure requiring dialysis29.824.4.50
Tracheostomy25.023.1.80
Failure to close abdomen6.124.2.008
Intestinal ischemia19.216.9.95

AAA, Abdominal aortic aneurysm.

There were 51 octogenarians. Twenty-seven of these patients (52.9%) did not survive to hospital discharge. In comparison, 38 of 119 patients (31.9%) younger than 80 suffered operative deaths. The 30-day mortality rate for octogenarians was significantly higher than the younger cohorts (51.0% vs 29.5%, P < .001). Fig 4 illustrates Kaplan-Meier survival estimate of octogenarians and the younger cohorts.

Of 139 patients who survived the first 24 hours after the initial operation intestinal ischemia developed in 27 patients (19.4%, 27/139). The diagnosis was confirmed either by endoscopy or operative findings of ischemic bowel in all but two patients. In these two patients, the diagnosis of bowel ischemia was made based on bloody bowel movements but the family declined additional diagnostic or therapeutic procedures; they both died. One additional patient died after withdrawal of care. Seven were managed conservatively of who three died; causes of death were pulmonary embolism in one patient and multiple system organ failure in two. Exploratory laparotomy and bowel resection was performed in 17 (63.0%, 17/27) of whom 10 eventually died of complications, including one of the seven patients who had an intraoperative inferior mesenteric artery (IMA) reimplantation. This patient underwent a left hemicolectomy but died on postoperative day 25 of multiple system organ failure. Affected bowel segments included small bowel in 2, cecum in 4, sigmoid colon in 9, and ileum and colon in 2 patients. Three patients died after withdrawal of care at the request of family. The in-hospital mortality rate in this subset of patients was 59.3% (16/27) (Fig 5). This is a statistically significant difference compared with the mortality rate of those without bowel ischemia (16.1%, 18/112, P = .002). Higher intraoperative blood product usage, intravenous fluid administration, and intraoperative hypotension were noted in patients with bowel ischemia compared with those without (Table V).

  • View full-size image.
  • Fig 5. 

    Kaplan-Meier analysis of survival after ruptured abdominal aortoiliac aneurysm repair. Survival is analyzed according to development of postoperative bowel ischemia.

Table V. Factors associated with development of postoperative bowel ischemia
VariableNo intestinal ischemiaIntestinal ischemiaP value
Operative time198.0±70.4244.4±88.5<.01
Intraop blood transfusion6.0±5.08.9±5.5.01
Intraop FFP transfusion3.3±4.25.2±4.6.04
Lowest intraop BP77.2±21.359.7±18.8.03

Intraop, Intraoperative; FFP, fresh frozen plasma; BP, blood pressure.

Acute renal failure requiring hemodialysis developed in 25 of 118 patients (21.2%) without prior history of chronic renal insufficiency (CRI) and who survived 24 hours. Three out of eight surviving patients at last follow-up were hemodialysis-dependent. Of 21 patients with history of preoperative CRI, 11 required hemodialysis (52.4%) during the postoperative period and, at last follow-up, all of the surviving patients were on permanent hemodialysis.

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Discussion 

This study illustrates that RAAA remains a difficult clinical problem even in a high-volume center. Of particular interest is a striking correlation between outcomes and the surgeon's annual AAA volume, a finding that has not received significant attention in the past. Advanced age and postoperative intestinal ischemia, factors which have been known to increase perioperative mortality, were again found to predict decreased survival.

Factors affecting mortality rates after RAAA repair have been studied extensively. Advanced age,5, 13, 22, 23 female gender,22, 23 preoperative cardiac arrest16, 24 and other comorbidities such as preoperative renal inusfficiency,16, 25 and chronic obstructive pulmonary disease5, 25, 26 have all been identified as predictors of poor outcome. One of the major predictors of mortality in this study was postoperative intestinal ischemia. Other studies have shown that the incidence of intestinal ischemia complicates repair of RAAA in up to 60% of initial survivors with reported mortality rates approaching 80% to 100% with transmural nerosis.27, 28, 29 Earlier attempts to identify predictors of colonic ischemia have identified preoperative shock, greater intraoperative blood loss, hypothermia, and acidosis,28, 29, 30, 31 while Meissner and Johansen32 found no clinical or operative factors other than low perioperative cardiac output. The findings in the present study concur with earlier studies in that intraoperative hypotension and increased intraoperative fluid and blood product administration were associated with development of this disastrous complication, resulting in a mortality rate of 59.3% in this subset of patients. In our experience, judicious use of blood products as well as fluids and avoidance of prolonged hypotension appear beneficial. Early recognition of clinical manifestation of bowel ischemia and prompt diagnosis is also critical, as is the case with any intra-abdominal septic process. There is no persuasive data for routine reimplantation of the IMA to prevent bowel ischemia,31 and the data in this study is not sufficient to support its routine use. In fact, the diffuse distribution of bowel segments involved, including the small bowel in four patients and the cecum in another four, suggests that hemodynamic compromise of the IMA distribution is certainly not a universal prerequisite for the clinical syndrome. Embolization to the viscera may account for most of bowel ischemia as proposed by Dadian et al33 and certainly can not be improved by IMA reimplantation. Regardless of the mechanism, bowel ischemia, indeed, remains the Achilles' heel of RAAA repair.29

Endovascular repair (EVAR) of RAAA has been proposed recently as a safe alternative to open repair for RAAA. Its perceived and reported benefits due to its minimally invasive approach accompanied by decreased transfusion requirements and shorter length of stay in the intensive care unit compared with open repair have enhanced its popularity as a viable option for the treatment of RAAA.10, 11, 12 In selected nonrandomized single center series, EVAR was associated with mortality rates ranging from 9.5% to 45%.14, 34 Larger-scale studies using data from NIS and Medicare databases have revealed mortality rates of 35.3% and 31.8%, respectively. In the only randomized controlled trial, no differences in mortality or postoperative complication rates were noted between patients undergoing EVAR and open repairs for RAAA.15 Furthermore, applicability of EVAR in this setting is obviously somewhat limited by anatomic suitability and hemodynamic instability of the patients, as well as by the capabilities of the institution and the surgeon. In the randomized trial about half (47%) of the patients were deemed unsuitable for EVAR because of anatomic criteria. Relaxation of anatomic exclusion criteria will allow more patients to be treated by EVAR but may also increase subsequent device- and aneurysm-related complications. In a longitudinal nonrandomized study, midterm outcomes revealed no late survival benefit with EVAR.35 As such, open repairs remain the mainstay of RAAA management and strategies to improve survival rates should continue to be explored.

Surgeons' volume appears to have a significant impact on treatment outcomes on vascular procedures.19 However, a significant discrepancy in the AAA literature exists for volume definition (low-volume surgeon ranging from 1∼26 elective AAA repairs/year and high-volume from 10∼26/year; low-volume hospital ranging from 1∼35/year and high-volume from >10/year to >79/year). This makes it difficult to interpret the data reported. Nonetheless, a positive trend exists between volume and outcome. Birkmeyer et al36 reported a progressively decreasing risk adjusted mortality rates from 7.8% to 4.4% with increasing hospital yearly volume of elective AAA repairs. In a follow-up study,37 they demonstrated the same phenomenon with respect to the surgeon volume; the adjusted mortality rates were 6.2% for low- volume surgeons (<8/year), 4.6% for medium-volume surgeons (8∼17.5/year), and 3.9% for high-volume surgeons (>17.5/year). Furthermore, they noted that the individual surgeon's outcome was not significantly dependent on the hospital volume. Kantonen et al38 also noted that hospital volume was not associated with better outcomes in patient undergoing elective AAA repairs and that any surgeon volume outcome relationship was solely due to actual surgeon volume.

For emergent AAA repair, the association of high-volume hospitals and outcome is not clear. Dardik et al5 did not show any correlation between hospital volume and mortality. In a meta-analysis, Holt et al6 also concluded that low-volume centers were associated with a significantly higher mortality rates. However, in another comprehensive review, Killeen et al19 concluded that hospital volume was not found to be as a significant predictor of outcome in emergent settings. The findings in the present study, with an overall mortality rate of 38.2%, are in agreement with Killeen et al.19

A surgeon's experience with RAAA, on the other hand, does appear to have an impact on outcome. Hannan et al39 in 1992 reported, in a state-wide review of New York, that surgeon's volume for RAAA repair was significantly related to improved mortality rates for RAAA repairs. In a province-wide review of Ontario, Canada, Dueck et al,8 found that the risk adjusted mortality rate after RAAA repairs was 45.5% for low-volume surgeons compared with 40.1% for high-volume surgeons (>5 RAAA repairs/year). Rutledge et al23 found that surgeon's cumulative experience with RAAA was associated with improved patient survival, while that with all AAA was not.

The present study differs from the aforementioned studies in that this was a review of a single center experience and that surgeons' annual elective AAA volume was noted to be a predictor of outcomes rather than RAAA volume. However, the findings in this study propose specifically that surgeons' experience reflected by the number of average annual AAA cases may be a significant determinant of outcome for RAAA repairs even in a high-volume referral center. The mortality rate for surgeons with high annual AAA volume in this report was 21.6% compared with 45.4% for surgeons with low annual AAA volume. Surgeon's experience in years was not associated with outcome in this study in agreement with Ouriel et al.25 Interestingly, in a longitudinal study, it was shown that individual surgeons' mortality rates did not change significantly over time, and that those with good outcomes had lower mortality rates even when their volumes were low in early part of the study than other surgeons with comparable volumes.39 In reference to postoperative complications, the only difference observed was the higher incidence of failure to close the abdomen at the completion of initial repair in the patient cohort treated by low-volume surgeons, an effect that was not found to be associated with mortality.

The underlying mechanism for the observed relationship between volume and outcome is not well elucidated.19 One postulate is that “practice makes perfect” ie, increased exposure and experience enhance the surgeon's proficiency. Specialty training in vascular surgery is also an important factor linked to improved outcomes.8, 17, 20, 23, 40, 41 The results in this study do not explain what contributes to the differences in outcome between the surgeons with high- and low volume. No tangible differences could be detected between the patients treated by these two groups of surgeons with respect to baseline characteristic or perioperative variables that could explain the difference in mortality. Since only 30% of the patients were treated by high-volume surgeons, the number of patients may have been too small to detect any differences between the two groups. It should be pointed out, however, that this study does not analyze the differences in intraoperative conduct of the operation such as a “judgment call” or other nuances that may lead to different course of the operation, which in turn may impact clinical outcome. In addition, the differences in the postoperative management among the surgeons or surgeon groups were not analyzed.

With the continued decrease in open aortic aneurysm repairs secondary to the widespread use of EVAR, this observed association between surgeon volume with mortality lends support to regionalization of aortic repair, especially in the setting of ruptured aortic aneurysms.16, 18 The competence and confidence of graduating fellows in vascular surgery with open aortic procedures may not be the same as those with endovascular therapy, and this deficiency, if present, would become more apparent when faced with life-threatening situations, such as RAAA. Regionalization would enhance vascular residents' experience and potentially increase their comfort level in such situations. The results in the present study, however, indicate that regionalization may not be sufficient to improve the survival rates in these patients and additional volume-driven strategies may need to be employed. Identification of high-volume surgeons with low mortality rates and development of a team dedicated to RAAA in a high-volume referral center may be an effective way of improving surgical outcome with this challenging pathology.

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Conclusions 

RAAA remains a highly lethal problem even in a high-volume tertiary referral center. Advanced age, postoperative bowel ischemia, and surgeons with low annual AAA volume were associated with poor early outcomes. Better results can be expected from experienced surgeons who perform greater than or equal to 20 elective open AAA repairs per year. With a paradigm shift towards less invasive modality in vascular surgery, the findings in this study bear suggest alternative treatment strategies, such as selective referral to high-volume centers and development of an aortic team comprised of high-volume surgeons and emergency staff, for the benefit of improved patient survival and residency training.

The authors gratefully acknowledge Ms Yeon Hee Kim for her statistical analysis.

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Author contributions 


Conception and design: JC

Analysis and interpretation: JC, MM, ED

Data collection: JK, JC, NG, LM, ED

Writing the article: JC, RR, JK, NG, LM, ED

Critical revision of the article: JC, JK, RR, LM, MM, ED

Final approval of the article: JC

Statistical analysis: JC

Obtained funding: Not applicable

Overall responsibility: JC

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 Competition of interest: none.

PII: S0741-5214(08)00330-3

doi:10.1016/j.jvs.2008.02.067

Journal of Vascular Surgery
Volume 48, Issue 1 , Pages 10-18, July 2008

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