Journal of Vascular Surgery
Volume 50, Issue 1 , Pages 15-22, July 2009

Thoracoabdominal aneurysm repair: Hybrid versus open repair

Division of Vascular and Endovascular Surgery, Massachusetts General Hospital, Boston, Mass

Received 18 September 2008; accepted 21 December 2008.

Article Outline

Objective

Hybrid repair of thoracoabdominal aortic aneurysms (TAAA) may reduce morbidity and mortality in high-risk candidates for open repair. This study reviews the outcomes of hybrid TAAA repair for Crawford extent I-III TAAA in high-risk patients in comparison to patients who underwent concurrent open TAAA repair.

Methods

During the interval from June 2005 to December 2007, a total of 23 high-risk patients with TAAA (type I: 9 [39%], II: 5 [22%], and III: 9 [39%]) underwent renal and/or mesenteric debranching (11 [48%] with four vessel debranching) with subsequent placement of a thoracic stent graft; 77 patients underwent open TAAA repair (type I: 13 [17%], II: 11 [14%], III: 27 [35%], and IV: 26 [34%]) during the same interval. The primary high-risk criteria for hybrid TAAA included advanced age/poor functional status (n = 14), major pulmonary dysfunction (n = 8), and technical consideration (prior thoracic aortic aneurysm repair [n = 4] or prior thoracoabdominal aneurysm repair [n = 2] and obesity [n = 2]) with 6 patients having overlapping high-risk criteria. Composite (30-day) mortality and/or permanent paraplegia (PP) were the major study endpoints.

Results

The hybrid and open TAAA groups had (respectively) no statistical difference in mean age (76.6 vs 72.7 years), aneurysm size (6.51 vs 6.52 cm), and non-elective operation (30.4% vs 26.0%). The hybrid group had a higher mean Society for Vascular Surgery (SVS) risk score (9.1 vs 6.0; P ≤ .001), incidence of oxygen-dependent chronic obstructive pulmonary disease (COPD) (34.8% vs 2.6%; P ≤ .001), and prior thoracic (n = 4) or thoracoabdominal (n = 2) repair (26.1% vs 1.3%; P ≤ .001). Composite mortality and/or PP was doubled in the hybrid group (21.7% vs 11.7%; P = .33). The rate of any type of reoperation was higher in hybrid TAAA repair (39.1% vs 20.8%; P = .03). One year actuarial survival for both groups was comparable (hybrid, 68 ± 12%; open, 73 ± 6%). A total of 5/23 (22%) hybrid TAAA patients developed an endoleak (type I: 3/23 and type II: 2/23) with 3 requiring endovascular re-intervention. A total of 7/70 (10%) visceral/renal bypass grafts were noted to be occluded during follow-up (1 superior mesenteric artery, 1 celiac, and 5 renal). Examination of patients with an SVS risk score ≤8 (mean SVS risk score in hybrid 6.2 [n = 10] vs 5.5 [n = 68] in open; P = .27) revealed the hybrid group had a higher incidence of composite mortality and/or PP (40% vs 10.3%; P = .03).

Conclusion

Hybrid TAAA repair in high-risk patients has significant morbidity and mortality suggesting a non-interventional approach may be appropriate in many such patients. The morbidity and mortality of the hybrid TAAA repair was substantial even in lower risk patients (SVS risk score ≤8), albeit patient numbers were small. Prospective study in comparable patient risk cohorts is required to define the role of hybrid TAAA repair.

 

Prior to the commercial availability of thoracic stent grafts, formal open operation was the only technical solution for the treatment of thoracoabdominal aortic aneurysm (TAAA). While favorable results have been achieved in high volume centers,1, 2, 3 the “real world” mortality of this operation across a spectrum of hospitals exceeds 20%.4 Rigberg et al5 noted an overall mortality of 19% at 1 year in the state of California with a linear, even dramatic correlation with patient age such that patients greater than 75 years of age had an aggregate 1 year mortality of 40% after TAAA repair. In our experience, perioperative mortality across a spectrum of patient clinical presentations has been a consistent 8% over the past 20 years.3, 6 Additional follow-up studies have documented both favorable durability of such repair7 and preserved functional status in long-term surviving patients.8 However, patients unfit to withstand open operation are commonly encountered and their prognosis is poor.9 Often significant chronic obstructive pulmonary disease (COPD) precludes open TAAA repair, with the clinical conundrum that such pulmonary disease constitutes an independent and well validated risk factor for aneurysm expansion and rupture.10, 11

There is consensus that endovascular aneurysm repair (EVAR) is the preferred treatment for high-risk patients with abdominal aortic aneurysms.12, 13 While totally endovascular-branched graft repair has been reported for high-risk TAAA patients,14, 15 the availability of such constructs in the United States is quite limited. Furthermore, given the significant logistical and regulatory technical issues with custom made branched grafts and the wide variability of visceral segment anatomy in TAAA patients, this situation is unlikely to change in the near future.

Hybrid operations which combine both open (typically visceral/renal debranching) and endovascular techniques were first reported in 1999.16 This consists of an open operation in which the visceral segment of the abdominal aorta is debranched via extra-anatomic bypass grafts originating from the distal abdominal aorta or iliac arteries to provide a distal seal zone for subsequent placement of a thoracic endograft. The endograft distal attachment site can be either in the native visceral segment, an infrarenal graft or even the iliac arteries.17

The hybrid repair of TAAA has been suggested to have lower mortality in high-risk patients18, 19 and is the preferred repair at certain centers20 largely with the rationale that open operation has produced unacceptable morbidity. Other reports of hybrid TAAA repair involving visceral vessels have demonstrated no significant difference in outcomes to open TAAA repair.21 Accordingly, the hybrid operation has been applied in heterogeneous patient groups in single center studies and no prospective comparative study of this strategy exists. In the present study, we report our experience with hybrid operations in patients unfit for open operation; for perspective and comparison, concurrently treated patients undergoing open TAAA are included.

Back to Article Outline

Methods 

This retrospective study of prospectively gathered clinical data was approved by the Massachusetts General Hospital Institutional Review Board. A total of 23 high-risk patients with thoracoabdominal aneurysms underwent either mesenteric or mesenteric and renal debranching with subsequent thoracic endograft placement between June 2005 and December 2007. These patients were compared with patients who underwent an open TAAA repair (n = 77) during the same time period.

Patients in the hybrid group were stratified as high risk for open repair based on advanced age/poor functional status (mean age 81 years, n = 14), severe oxygen-dependent COPD (n = 8), obesity (n = 2), or previous open thoracic (n = 4) or TAAA repair (n = 2) with 6 patients having overlapping high-risk criteria. The median age for this group was 76.6 years with a range of 59 to 86 years. The mean aneurysm size was 6.5 cm (range, 5.2 to 8.5 cm). A total of 69.6% of the hybrid patients presented on an elective basis and TAAA extent by Crawford classification was; type I: 9 (39%), type II: 5 (22)%, type III: 9 (39%), and type IV: 0 (0%). Hybrid TAAA repair was not considered for patients with extent IV TAAA as the perceived surgical insult for debranching equates that of formal open repair of such lesions. The majority (n = 13) of patients underwent staged repair with a mean interval between stages of 3 days excluding 1 patient who had a delayed interval of 82 days partly due to a myocardial infarction after the first surgery. Ten patients underwent a single-staged procedure.

Staged patients underwent debranching of the renal and/or mesenteric vessels first followed by placement of a thoracic endograft (W.L. Gore & Assoc, Flagstaff, Ariz) including coverage of the visceral vessel origins. Single-staged procedures involved the mesenteric debranching followed by the placement of the thoracic endograft. Since long segment thoracic aortic coverage was routine, placement of a cerebrospinal fluid drainage catheter was used in all hybrid cases. Mesenteric debranching was performed via a midline laparotomy with multi-branched Dacron grafts sutured to the native infrarenal aorta (n = 5), infrarenal graft placed during debranching (n = 7), previous infrarenal graft (n = 8), or native iliac arteries (n = 3). Debranching involved all four mesenteric/renal vessels (n = 11), mesenteric alone (n = 8), or a variation thereof (n = 4). Placement of the thoracic endograft was via the femoral arteries or conduit if the iliac artery diameter would not accommodate the device. Postoperatively, all patients were placed in the intensive care unit. The cerebrospinal catheter was removed 48-72 hours thereafter. Patient follow-up was at 1 month, between 3 to 6 months, and at 1 year. The Social Security Death Index, hospital computerized records, or telephone follow-up were used to verify patient deaths. Preoperative Society for Vascular Surgery (SVS) risk scores were calculated in a manner previously reported.22

The open TAAA group consisted of 77 consecutive patients (Crawford extent type I: 13 [17%], type II: 11 [14%], type III: 27 [35%], and type IV: 26 [34%]) who underwent open TAAA repair during the same time period as the hybrid patients' treatment. The mean age for the patient population was 72.7 years (range, 38-92 years) and the mean aneurysm size was 6.5 cm (range, 4-10 cm). A total of 74.0% underwent elective repair. Preoperative SVS scores were calculated in a similar manner as in the hybrid group. During surgery, routine use of cerebrospinal catheter drainage was employed in extent I-III TAAA. Details of the technical aspects of surgery have been previously reported.6 Patients were evaluated at 1 month and at 1 year.

The two groups were compared using χ2 and Fisher's exact t test where appropriate. Primary endpoints of this study were mortality, permanent neurological deficit, and composite mortality and/or permanent neurological deficit. Secondary endpoints included intermediate term actuarial survival, myocardial infarction, and any surgical re-intervention at any time. Time-based endpoints were analyzed using Kaplan-Meier life table analysis.

Back to Article Outline

Results 

Demographics and clinical features of the study groups are displayed in Table I. Cardiopulmonary comorbidities and composite SVS risk score were significantly elevated in the hybrid group. There was no significant difference in aneurysm size and nonelective operation between groups; however the hybrid group was noted to have a higher proportion of patients with reoperative thoracic or descending TAAA repairs as detailed in Table II.

Table I. Demographic and clinical features
Hybrid repair n = 23Open repair n = 77P value
Age (years)76.6±7.172.7±10.1.085
Male7(30.4%)36(46.8%).165
Diabetes mellitus6(26.1%)8(10.4%).057
Severe COPD (oxygen dependant)8(34.8%)2(2.6%)<.0001
Hypertension (severe: 3 or + meds)11(47.8%)18(23.4%).023
Tobacco (past or current)16(69.6%)29(37.7%).007
Compensated CHF or arrhythmia10(43.5%)15(19.5%).020
Creatinine, serum (>1.5 mg/dL)5(23.8%)27(35.1%).434
SVS risk score9.13±3.176.01±2.25<.0001

COPD, Chronic obstructive pulmonary disease; CHF, congestive heart failure; SVS-ISCVS risk score.22

Table II. Preoperative anatomy and clinical presentation
Hybrid repair n = 23Open repair n = 77P value
TAAA extent
I9(39%)13(17%)
II5(22%)11(14%)
III9(39%)27(35%)
IV0(0%)26(34%)
Mean aneurysm size (cm)6.51±0.76.52±1.04.947
All prior aortic operations
AAA6(26.1%)20(26.0%).991
Asc/arch2(8.7%)4(5.2%).619
TAA/TAAA6(26.1%)1(1.3%).001
Clinical presentation
Elective16(69.6%)57(74.0%).912
Urgent nonruptured5(21.7%)14(18.2%)
Ruptured2(8.7%)6(7.8%)

AAA, Abdominal aortic aneurysm; Asc/arch, ascending or aortic arch aneurysm; TAA, thoracic aortic aneurysm; TAAA, thoracoabdominal aortic aneurysm.

The hybrid group had a greater than twofold increase in perioperative death but, as detailed in Table III, this did not achieve statistical significance. There were six ruptures in the open group with two deaths representing 25% of the in-hospital deaths and two ruptures in hybrid group with one death representing 17% of the in-hospital deaths; with such small numbers data analysis was not performed specifically examining mortality in rupture vs elective patients in the hybrid and open groups. Excluding type IV TAAA from the open group as the hybrid group did not have any type IV TAAA, did not significantly alter in-hospital mortality (hybrid, 26% vs open, 13%; P = .17). The Kaplan-Meier curve demonstrated no difference in survival at 1 year between the two groups (Fig) albeit this analysis is hampered by small numbers available for such follow-up at 1 year. Both groups had similar rates of paraplegia. Interestingly, the hybrid group had a significantly higher rate of any surgical re-intervention (34.8% vs 20.8%; P = .03) such as required for tracheostomy, bleeding, wound disruption, endoleak, graft thrombosis, etc. Postoperative complication rates for renal failure, arrhythmia, and pneumonia were not different. There was a trend towards a high rate of myocardial infarction in the hybrid group (21.7% vs 9.1%; P = .14), however, this was not statistically significant. Of note, hybrid-specific complications included a 10% graft thrombosis rate (7/70 bypass grafts) with 1 patient having 3/4 grafts thrombosed due to heparin-induced thrombocytopenia and 5/23 patients (22%) developing an endoleak with 3 patients requiring a total of four endovascular re-interventions. The details describing preoperative and operative variables in addition to complications and deaths in the hybrid group are detailed in Table IV.

Table III. Complications and disposition
Hybrid repair n = 23Open repair n = 77P value
Perioperative death (30 day)4(17.4%)6(7.8%).232
In-hospital Death6(26.1%)8(10.4%).271
Paraplegia (permanent)1(4.3%)3(3.9%).983
Composite death and paraplegia (30 day)5(21.7%)9(11.7%).334
Cardiac
Myocardial infarction5(21.7%)7(9.1%).14
Arrhythmia3(13.0%)8(10.4%).712
Stroke0(0%)1(1.3%)1
Pulmonary
Pneumonia4(17.4%)14(18.2%)1
Tracheostomy1(4.3%)11(14.3%).286
Any reoperation9(39.1%)16(20.8%).033
Length of stay (days)14.9(3-69)18.3(0-98).369
Disposition upon discharge
Home3(13.0%)14(18.2%)
Rehabilitation/skilled nursing home14(60.9%)54(70.1%)

Perioperative death was defined as any death ≤ 30 days; In-hospital death was defined as any death which occurred during same hospitalization as the hybrid or open thoracoabdominal aneurysm operation; composite death and paraplegia were defined as either death and/or permanent paraplegia ≤ 30 days.

  • View full-size image.
  • Fig. 

    Open: Mean follow-up 179 days (median 100) (range, 1 to 710). Hybrid: Mean follow-up 166 days (median 68) (range, 2 to 580).

  • Interval start timeNumber entering intervalNumber withdrawing during intervalCumulative proportion surviving at end of interval ± SE
    Hybrid0-1year2350.68±0.12
    1-2years310.34±0.25
    Open0-1year77140.73±0.06
    1-2years1400.73±0.06

Table IV. Demographic and follow-up data for 23 patients who underwent TAAA hybrid procedure
NameAgeSvs Risk ScoreCrawford ExtentPrior SurgeryClinical PresentationStagesVisceral BypassesReoperation IndicationsComplications
RS83123 ElectiveStagedLRA, RRA, C, SMADehiscence
AG77113AAAUrgentConcurrentLRA, RRA, SP, SMAFemoral artery bleedingMI
WD6482TAAUrgent (enteric fistula)ConcurrentC, SMAExplant due to exposed endograft in esoph, tracheostomyPneumonia, sepsis (death)
FO80141TAAAUrgentConcurrentC, SMA Type 2 endoleak
SM85113AAAElectiveConcurrentLRA, SMA
GG8043TAAElectiveStagedLRA, RRA, C, SMA MI, graft thrombosis (RRA)
MG75142AAElectiveConcurrentLRA, RRA, C, SMA graft thrombosis (LRA and RRA), on Hemodialysis
JC7682 ElectiveStagedLRA, RRA, C, SMA Paraplegia (resolved with spinal drainage)
SL60101 ElectiveStagedLRA, RRA, C, SMA Type 2 endoleak
FB8021 ElectiveStagedLRA, RRA, C, SMACraniotomy for subdural hemorrhagePermanent paraplegia, MI
MP8671AAAElectiveStagedLRA, RRA, C, SMA Pneumonia, ARDS (death), MI, graft thrombosis (LRA), Renal Failure
BR8362 UrgentStagedLRA, RRA, C, SMA Cardiac arrest (death)
DO7591 ElectiveStagedC, SMAType 1 endoleak repairType 1 endoleak
JM81121AAA, TAAARuptureConcurrentRRA, C, SMACommon bile duct injuryPneumonia, Liver failure (death)
RL76143TAA, AAARuptureConcurrentSMA Sepsis, Pneumonia
CM82113AAAElectiveConcurrentC, SMAType 1 endoleak repairType 1 endoleak
AF8293 UrgentStagedRRA, C, SMA
TF72101 ElectiveStagedC, SMAType 1 endoleak repair × 2Type 1 endoleak
CS7973 ElectiveConcurrentLRA, RRA, C, SMA Rupture of TAAA between staged procedure (death)
ER7361TAAElectiveStagedLRA, RRA, C
HT7773 ElectiveConcurrentLRA, RRA, C, SMAGraft thrombectomyGraft thrombosis (C, SMA, and RRA) (death)
RL63111AAAElectiveStagedC, SMA MI
LB6071 ElectiveStagedC, SMA

AA, Aortic arch aneurysm; AAA, abdominal aortic aneurysm; ARDS, acute respiratory distress syndrome; C, celiac artery; LRA, left renal artery; MI, myocardial infarction; RRA, right renal artery; SMA, superior mesenteric artery; SP, splenic artery; TAA, thoracic aortic aneurysm; TAAA, thoracoabdominal aortic aneurysm.

Indications for any surgical reoperation are depicted. Complication detailing graft thrombosis and type and any complication attributed to death are clearly marked with death in parenthesis.

Subgroup analysis of patients with similar SVS risk scores between the two groups was used in an attempt to compare periprocedural results among similar risk profile patients. As with the main group, there was no difference in the major categories in patient demographics (Table V) in both subgroups of hybrid (n = 10) and open (n = 68) patients. Composite 30-day mortality and/or permanent paraplegia rates was noted to be higher in the hybrid group (40% vs 10.3%; P = .03), although small patient numbers hamper such analysis.

Table V. Demographics, preoperative anatomy and complications in patients with SVS ≤8
Hybrid repair N = 10Open repair N = 68P value
Age76.2±8.372.5±10.6.299
Gender (male)2(20%)30(44.1%).184
Diabetes mellitus2(20.0%)5(7.4%).219
Severe COPD1(10.0%)0(0%).031
Hypertension (severe: 3 or + meds)4(40.0%)13(19.1%).212
Hypercholesterolemia3(30.0%)38(55.9%).178
Tobacco (past or current)4(40.0%)24(35.3%).740
Compensated CHF or arrhythmia3(30.0%)11(16.2%).373
Serum Creatinine (>1.5 mg/dL)2(20.0%)22(32.4%).715
SVS risk score6.20±1.875.51±1.83.274
TAA extent
I5(50%)12(17.6%)
II2(20%)9(13.2%)
III3(30%)23(33.8%)
IV022(32.3%)
Mean aneurysm size (cm)6.43±0.736.47±1.02.918
All prior aortic operations
AAA1(10.0%)19(27.9%).438
Asc/arch1(10.0%)3(4.4%).429
TAA/TAAA3(30.0%)1(1.5%).006
Clinical presentation
Elective8(80.0%)50(73.5%)
Urgent nonruptured2(20.0%)6(8.8%)
Ruptured06(8.8%)
Postoperative MI3(30.0%)5(7.4%).061
Perioperative death3(30.0%)5(7.4%).061
Paraplegia1(10.0%)3(4.4%).553
Composite death and paraplegia4(40.0%)7(10.3%).03
Length of stay (days)17.1±2018.6±16.7.795

Back to Article Outline

Discussion 

From a practical standpoint, the hybrid operation has been available to most surgeons since commercial approval of the first thoracic endograft in April 2005.23 It is acknowledged that this technique will serve as a stopgap measure until widespread availability of branched thoracoabdominal endografts wherein impressive early results in high-risk patients has recently been reported in patients considered unfit candidates for open repair.15 Albeit the comparison is on the basis of small numbers, a periprocedural mortality of 9.1% as noted by Chuter et al15 compares favorably with the results detailed herein. Considering regulatory and logistical constraints in the current generation of branched endografts viz, the significant time delay in their fabrication, widespread availability is hardly imminent. Thus, the hybrid operation will likely remain in the armamentarium of the vascular surgeon for the foreseeable future, at least in application for urgent cases wherein delays in treatment for custom stent graft fabrication are not possible.

Given the significant morbidity and mortality of open TAAA, especially beyond high volume centers,4 limiting the scope of the operation, especially for patients with major comorbidities, seems intuitively logical. Hybrid repair by the avoidance of the thoracotomy, potential paralysis of the left hemi-diaphragm, and cross-clamping of the aorta, at least in theory, has the potential to decrease overall morbidity. The potential benefit of reduced spinal cord ischemia has also been suggested,20 but in fact not realized in the available literature. Our focus was to review results in patients denied open repair similar to the original EVAR paradigm.13, 24 A significant proportion of the hybrid patients (n = 18; 78%) were followed for a period of time as they were not candidates for open operation given their comorbidities. Perhaps most notable in this regard were patients with severe COPD. The patient with severe COPD and TAAA constitutes a common judgmental paradox as they are both at increased risk of pulmonary complications after operation and aneurysm expansion and rupture prior to surgery.9, 10, 11 In Crawford's series of 94 patients denied open operation for TAAA, 46% of such judgments were related to COPD;9 8 (35%) of our patients underwent hybrid repair related to severe COPD. It seemed intuitively logical that avoidance of a thoracotomy and disturbance of the left hemidiaphram function would translate into decreased pulmonary morbidity, the single most frequent occurring complication of open TAAA repair.3 Hybrid operation may also have an advantage in the setting of redo thoracotomy, wherein bleeding and left lung contusion are potentially problematic.25

The hybrid repair has been suggested to have lower spinal cord ischemia with paraplegia rates reported from 0%20 to as high as 16%19 (Table VI). This rationale is based on the avoidance of aortic cross-clamping and also as an extension of the experience with thoracic endovascular aneurysm repair (TEVAR) for repair of isolated thoracic aneurysms.26, 27 Several comparative trials have documented decreased risk of spinal cord ischemia complications with TEVAR vs open repair of thoracic aortic aneurysms.27, 28 However, similar to results in this study, our experience with TEVAR for isolated descending aneurysm dispute this purported advantage for TEVAR.29 Presumably this is referable to our favorable results with low rates of spinal cord ischemia as reported herein and previously.3, 6, 29 The comparison between TEVAR for descending aortic aneurysms and hybrid repair of TAAA is not valid as hybrid operations involve long segment thoracoabdominal coverage which has been shown to increase spinal cord ischemic complication;30 hybrid operations may also involve replacement of the infrarenal segment of the aorta in addition to thoracoabdominal stent graft placement, again increasing the risk for spinal cord ischemia. While touted as a surgery of limited extent, hybrid repair of TAAA is yet an operation of significant magnitude; given the small numbers of patients studied in recent reports, no firm conclusions can be made regarding the benefit of hybrid operations with respect to spinal cord ischemia. In fact, the low paraplegia rates reported by Black et al20 are specious. These investigators having updated their series, now report paraplegia rates of 15-20%.31

Table VI. Summary of results from previous hybrid TAAA papers
AuthorPatients (n)% unfit for open repairExtent I/IIMortality (30 day)ParaplegiaEndoleakDebranching graft patency
Black1926a (completed procedure)unknown10%/62%23%b(overall)0%42%98%
Chiesa2013100%54%/15%23%8% n = 1 (delayed)0%100%
Zhou17c31 (15 visceral)100%17%/0%3%(n=1)0%6%95%
Brockler1828100%9%/29%14%16%18%89% (30 day)
Current series23100%36%/23%17%4%22%90%

aThis series reported 29 patients in which hybrid was attempted with 26 patients successfully completing the hybrid and 3 patients having the procedure aborted;

bOverall mortality included the six rupture patients who died, for elective/urgent repair 30-day mortality was reported as 13%;

cthis series included hybrid arch debranching in addition to hybrid mesenteric debranching.

Patient selection for hybrid operations has been varied in the literature. The majority of studies, as with ours, have described the hybrid operation in patients unfit for traditional open repair.18, 19, 21 In fact, 18/23 (78%) of our hybrid group had been followed with TAAA prior to the study interval and offered hybrid repair once this became feasible from a regulatory perspective. Our own results and those of Chiesa et al21 demonstrated significant mortality in high-risk patients. At least one center invoking unacceptable risks of open TAAA repair have applied hybrid operation for all TAAAs.20 Including the ruptured patients, their overall 30-day mortality was 23%. Also, our study did not include any type IV TAAAs for the hybrid operation. In this particular patient group, the extent of the incision, context, and duration of the operation demonstrate no definitive advantage with traditional open repair. While our data did compare hybrid patients with all patients undergoing open TAAA repair, exclusion of type IV TAAA from the open group did not change overall results. While there is consensus that TAAA extent greatly influences the risk of spinal cord ischemic complications, our prior experience indicated no relation between TAAA extent and perioperative mortality.3, 6

The capacity for endoleaks (Table VI) is a disadvantage of hybrid repair and the relatively high incidence accompanying hybrid TAAA repair presumably relates to compromised fixation sites. Perhaps this could be improved by routinely performing four vessel debranching, but our experience indicates this strategy is to be avoided unless anatomically mandated. Endoleak rates as high as 42%20 have been reported (Table VI). A significant proportion of the endoleaks involved (type I) proximal and distal attachment sites which required reintervention. In one series,20 4/6 patients with type I leaks underwent reintervention with 3 patients still having an endoleak. Three of our patients required reintervention for type I endoleaks with one reintervention failure.

Another concern identified in the hybrid TAAA repair was the unexpectedly high rate (10%) of renal/visceral graft thrombosis. Exclusion of 1 patient with heparin-induced thrombocytopenia (HIT) syndrome and thrombosis of three out of four grafts would modulate our rate of graft thrombosis to 6%, similar to previously published reports.18 Also, exclusive of the patient with heparin-induced thrombocytopenia, all of the thrombosed grafts were to the renal arteries. Given our prior reports of the reliability/durability of surgical renal artery reconstruction,32 a failure rate of 19% (5/27) was surprising, especially when our previously reported renovisceral thrombosis rate in patients undergoing open TAAA repair was 1.6%.7 Likely, the technical nuances of reconstruction of (in particular) the right renal artery around a significant aneurysm and problems with a redo surgical field, contributed to the significant problem with graft thromboses. Technical options for creation of the debranching bypasses are many and have been reviewed elsewhere.33

Technical considerations of the hybrid operation also include the consideration of a simultaneous approach or a two-stage procedure.19, 33 This reflects an operation in evolution. Proponents of the simultaneous approach argue minimal access site-related complications as a conduit directly on the aorta or iliac artery can be utilized and direct surgical adjuncts can facilitate identification of the distal landing zone. Disadvantages include longer duration of operation, logistical constraints with imaging equipment, and an increased risk of renal failure given the ischemic time coupled with contrast administration.

Proponents of the two-staged approach argue improved recovery and avoidance of simultaneous abdominal and thoracic grafting which has been correlated in some reports with increased risk of spinal cord ischemia.34 Disadvantage of the two-stage approach includes the possibility of interval rupture which, in fact, occurred in our very first patient and in the experience of others.19

Limitations of the current study, similar to the majority of previously published reports of hybrid repair of TAAA, are its retrospective nature and the heterogeneity of the study groups with respect to risk factor profile. Inclusion of the open group is perhaps more for perspective rather than comparison. The small numbers of patients in this study, especially when comparing patients with SVS risk score of ≤8, was also a limiting factor. The analogy with extending EVAR and TEVAR to high-risk patients may not extend to hybrid repair of TAAAs. With a sobering 26% in-hospital mortality, it is clear that a conservative application of this strategy in patients unfit for conventional operation is appropriate. We currently reserve it for large TAAAs in patients with normal renal function. Prospective study of hybrid TAAA repair to open operation in similar risk patients will be required to define its role.

Back to Article Outline

Author contributions 


Conception and design: RP, MC, CK, RC

Analysis and interpretation: RP, VP, TC, RC

Data collection: RP, VP

Writing the article: RP, RC

Critical revision of the article: RP, RC

Final approval of the article: RP, RC

Statistical analysis: TC, RP, MC, VP

Obtained funding: RC

Overall responsibility: RP

Back to Article Outline

References 

  1. Coselli JS, Bozinovski J, LeMaire SA. Open surgical repair of 2286 thoracoabdominal aortic aneurysms. Ann Thorac Surg. 2007;83:S862–S864discussion S890-2
  2. Svensson LG, Crawford ES, Hess KR, Coselli JS, Safi HJ. Experience with 1509 patients undergoing thoracoabdominal aortic operations. J Vasc Surg. 1993;17:357–368discussion 368-70
  3. Conrad MF, Crawford RS, Davison JK, Cambria RP. Thoracoabdominal aneurysm repair: a 20-year perspective. Ann Thorac Surg. 2007;83:S856–S861discussion S890-2
  4. Cowan JA, Dimick JB, Henke PK, Huber TS, Stanley JC, Upchurch GR. Surgical treatment of intact thoracoabdominal aortic aneurysms in the United States: hospital and surgeon volume-related outcomes. J Vasc Surg. 2003;37:1169–1174
  5. Rigberg DA, McGory ML, Zingmond DS, Maggard MA, Agustin M, Lawrence PF, et al. Thirty-day mortality statistics underestimate the risk of repair of thoracoabdominal aortic aneurysms: a statewide experience. J Vasc Surg. 2006;43:217–222discussion 223
  6. Cambria RP, Clouse WD, Davison JK, Dunn PF, Corey M, Dorer D. Thoracoabdominal aneurysm repair: results with 337 operations performed over a 15-year interval. Ann Surg. 2002;236:471–479discussion 479
  7. Clouse WD, Marone LK, Davison JK, Dorer DJ, Brewster DC, LaMuraglia GM, et al. Late aortic and graft-related events after thoracoabdominal aneurysm repair. J Vasc Surg. 2003;37:254–261
  8. Crawford RS, Pedraza JD, Chung TK, Corey M, Conrad MF, Cambria RP. Functional outcome after thoracoabdominal aneurysm repair. J Vasc Surg. 2008;48:828–835
  9. Crawford ES, DeNatale RW. Thoracoabdominal aortic aneurysm: observations regarding the natural course of the disease. J Vasc Surg. 1986;3:578–582
  10. Lobato AC, Puech-Leão P. Predictive factors for rupture of thoracoabdominal aortic aneurysm. J Vasc Surg. 1998;27:446–453
  11. Juvonen T, Ergin MA, Galla JD, Lansman SL, Nguyen KH, McCullough JN, et al. Prospective study of the natural history of thoracic aortic aneurysms. Ann Thorac Surg. 1997;63:1533–1545
  12. Sicard GA, Zwolak RM, Sidawy AN, White RA, Siami FS Society for Vascular Surgery Outcomes Committee. Endovascular abdominal aortic aneurysm repair: long-term outcome measures in patients at high-risk for open surgery. J Vasc Surg. 2006;44:229–236
  13. Hua HT, Cambria RP, Chuang SK, Stoner MC, Kwolek CJ, Rowell KS, et al. Early outcomes of endovascular versus open abdominal aortic aneurysm repair in the National Surgical Quality Improvement Program-Private Sector (NSQIP-PS). J Vasc Surg. 2005;41:382–389
  14. Roselli EE, Greenberg RK, Pfaff K, Francis C, Svensson LG, Lytle BW. Endovascular treatment of thoracoabdominal aortic aneurysms. J Thorac Cardiovasc Surg. 2007;133:1474–1482
  15. Chuter TA, Rapp JH, Hiramoto JS, Schneider DB, Howell B, Reilly LM. Endovascular treatment of thoracoabdominal aortic aneurysms. J Vasc Surg. 2008;47:6–16
  16. Quiñones-Baldrich WJ, Panetta TF, Vescera CL, Kashyap VS. Repair of type IV thoracoabdominal aneurysm with a combined endovascular and surgical approach. J Vasc Surg. 1999;30:555–560
  17. Flye MW, Choi ET, Sanchez LA, Curci JA, Thompson RW, Rubin BG, et al. Retrograde visceral vessel revascularization followed by endovascular aneurysm exclusion as an alternative to open surgical repair of thoracoabdominal aortic aneurysm. J Vasc Surg. 2004;39:454–458
  18. Zhou W, Reardon M, Peden EK, Lin PH, Lumsden AB. Hybrid approach to complex thoracic aortic aneurysms in high-risk patients: surgical challenges and clinical outcomes. J Vasc Surg. 2006;44:688–693
  19. Bockler D, Kotelis D, Geisbüsch P, Hyhlik-Dürr A, Klemm K, von Tengg-Kobligk H, et al. Hybrid procedures for thoracoabdominal aortic aneurysms and chronic aortic dissections - a single center experience in 28 patients. J Vasc Surg. 2008;47:724–732
  20. Black SA, Wolfe JH, Clark M, Hamady M, Cheshire NJ, Jenkins MP. Complex thoracoabdominal aortic aneurysms: endovascular exclusion with visceral revascularization. J Vasc Surg. 2006;43:1081–1089discussion 1089
  21. Chiesa R, Tshomba Y, Melissano G, Marone EM, Bertoglio L, Setacci F, et al. Hybrid approach to thoracoabdominal aortic aneurysms in patients with prior aortic surgery. J Vasc Surg. 2007;45:1128–1135
  22. Rutherford RB, Baker JD, Ernst C, Johnston KW, Porter JM, Ahn S, et al. Recommended standards for reports dealing with lower extremity ischemia: revised version. J Vasc Surg. 1997;26:517–538
  23. Makaroun MS, Dillavou ED, Kee ST, Sicard G, Chaikof E, Bavaria J, et al. Endovascular treatment of thoracic aortic aneurysms: results of the phase II multicenter trial of the GORE TAG thoracic endoprosthesis. J Vasc Surg. 2005;41:1–9
  24. Chuter TA, Gordon RL, Reilly LM, Kerlan RK, Sawhney R, Jean-Claude J, et al. Abdominal aortic aneurysm in high-risk patients: short- to intermediate-term results of endovascular repair. Radiology. 1999;210:361–365
  25. Kawaharada N, Morishita K, Fukada J, Hachiro Y, Takahashi K, Abe T. Thoracoabdominal aortic aneurysm repair through redo left-sided thoracotomy. Ann Thorac Surg. 2004;77:1304–1308
  26. Fairman RM, Criado F, Farber M, Kwolek C, Mehta M, White R, et al. Pivotal results of the Medtronic Vascular Talent Thoracic Stent Graft System: the VALOR trial. J Vasc Surg. 2008;48:546–554
  27. Bavaria JE, Appoo JJ, Makaroun MS, Verter J, Yu ZF, Mitchell RS Gore TAG Investigators. Endovascular stent grafting versus open surgical repair of descending thoracic aortic aneurysms in low-risk patients: a multicenter comparative trial. J Thorac Cardiovasc Surg. 2007;133:369–377
  28. Matsumura JS, Cambria RP, Dake MD, Moore RD, Svensson LG, Snyder S TX2 Clinical Trial Investigators. International controlled clinical trial of thoracic endovascular aneurysm repair with the Zenith TX2 endovascular graft: 1-year results. J Vasc Surg. 2008;47:247–257discussion 257
  29. Stone DH, Brewster DC, Kwolek CJ, Lamuraglia GM, Conrad MF, Chung TK, et al. Stent-graft versus open-surgical repair of the thoracic aorta: mid-term results. J Vasc Surg. 2006;44:1188–1197
  30. Carroccio A, Marin ML, Ellozy S, Hollier LH. Pathophysiology of paraplegia following endovascular thoracic aortic aneurysm repair. J Card Surg. 2003;18:359–366
  31. Wolfe JH. Data presented at Houston Aortic Summit. April 2008;
  32. Cambria RP, Brewster DC, L'Italien GJ, Moncure A, Darling RC, Gertler JP, et al. The durability of different reconstructive techniques for atherosclerotic renal artery disease. J Vasc Surg. 1994;20:76–85discussion 86-7
  33. Fulton JJ, Farber MA, Marston WA, Mendes R, Mauro MA, Keagy BA. Endovascular stent-graft repair of pararenal and type IV thoracoabdominal aortic aneurysms with adjunctive visceral reconstruction. J Vasc Surg. 2005;41:191–198
  34. Buth J, Harris PL, Hobo R, van Eps R, Cuypers P, Duijm L, et al. Neurologic complications associated with endovascular repair of thoracic aortic pathology: incidence and risk factors (A study from the European Collaborators on Stent/Graft Techniques for Aortic Aneurysm Repair (EUROSTAR) registry). J Vasc Surg. 2007;46:1103–1110discussion 1110-1

 Supported in part by the Harold and June Geneen Vascular Research Fund.

 Competition of interest: none.

PII: S0741-5214(08)02290-8

doi:10.1016/j.jvs.2008.12.051

Journal of Vascular Surgery
Volume 50, Issue 1 , Pages 15-22, July 2009

Article Tools

* Image Usage & Resolution