Comparative outcomes of open mesenteric bypass after a failed endovascular or open mesenteric revascularization for chronic mesenteric ischemia.

INTRODUCTION: Clinical practice guidelines have recommended an endovascular-first approach (ENDO) for the management of patients with chronic mesenteric ischemia (CMI), whereas an open mesenteric bypass (OMB) is proposed for subjects deemed to be poor ENDO candidates. However, the impact of a previous failed endovascular or open mesenteric reconstruction on a subsequent OMB is unknown. Accordingly, this study was designed to examine the results of a remedial OMB (R-OMB) after a failed ENDO or a primary OMB (P-OMB) for patients with recurrent CMI. METHODS: All patients who underwent an OMB from 2002 to 2022 at the University of Florida were reviewed. Outcomes after an R-OMB (ie, history of a failed ENDO or P-OMB) and P-OMB were compared. The primary end point was 30-day mortality, whereas secondary outcomes included complications, reintervention, and survival. The Kaplan-Meier methodology was used to estimate freedom from reintervention and all-cause mortality, whereas multivariable Cox proportional hazards modeling identified predictors of death. RESULTS: A total of 145 OMB procedures (R-OMB, n = 48 [33%]; P-OMB, n = 97 [67%]) were analyzed. A majority of R-OMB operations were performed for a failed stent (prior ENDO, n = 39 [81%]; prior OMB, n = 9 [19%]). R-OMB patients were generally younger (66 ± 9 years vs P-OMB, 69 ± 11 years; P = .09) and had lower incidence of smoking exposure (29% vs P-OMB, 48%; P = .07); however, there were no other differences in demographics or comorbidities. R-OMB was associated with less intraoperative transfusion (0.6 units vs P-OMB, 1.4 units; P = .01), but there were no differences in conduit choice or bypass configuration.The overall 30-day mortality and complication rates were 7% (n = 10/145) and 53% (n = 77/145), respectively, with no difference between the groups. Notably, R-OMB had decreased cardiac (6% vs P-OMB, 21%; P < .01) and bleeding complication rates (2% vs P-OMB, 15%; P = .01). The freedom from reintervention (1 and 5 years: R-OMB: 95% ± 4%, 83% ± 9% vs P-OMB: 97% ± 2%, 93% ± 5%, respectively; log-rank P = .21) and survival (1 and 5 years: R-OMB: 82% ± 6%, 68% ± 9% vs P-OMB: 84% ± 4%, 66% ± 7%; P = .91) were similar. Independent predictors of all-cause mortality included new postoperative hemodialysis requirement (hazard ratio [HR], 7.4, 95% confidence interval [CI], 3.1-17.3; P < .001), pulmonary (HR, 2.7, 95% CI, 1.4-5.3; P = .004) and cardiac (HR, 2.4, 95% CI, 1.1-5.1; P = .04) complications, and female sex (HR, 2.1, 95% CI, 1.03-4.8; P = .04). Notably, R-OMB was not a predictor of death. CONCLUSIONS: The perioperative and longer-term outcomes for a remedial OMB after a failed intraluminal stent or previous open bypass appear to be comparable to a P-OMB. These findings support the recently updated clinical practice guideline recommendations for an endovascular-first approach to treating recurrent CMI due to the significant perioperative complication risk of OMB. However, among the subset of patients deemed ineligible for endoluminal reconstruction after failed mesenteric revascularization, R-OMB results appear to be acceptable and highlight the utility of this strategy in selected patients.

A registry-based study of paclitaxel drug-coated balloon angioplasty for the treatment of in-stent restenosis of the femoral-popliteal artery.

OBJECTIVE: The aim of this study was to report the results of a prospective, single-arm, registry-based study assessing the safety and performance of a paclitaxel drug-coated balloon (DCB) for the treatment of superficial femoral artery (SFA) or popliteal artery in-stent restenosis (ISR) in a United States population. METHODS: We conducted a prospective, non-randomized, multi-center, single-arm, post-market registry of the IN.PACT Admiral DCB for the treatment of ISR lesions in the SFA or popliteal artery at 43 sites within the Society for Vascular Surgery (SVS) Vascular Quality Initiative (VQI) Registry from December 2016 to January 2020. Clinical outcomes were assessed at 12, 24, and 36 months. The primary endpoint was target lesion revascularization at 12 months. Secondary endpoints included technical success, target vessel revascularization, major limb amputation, and all-cause mortality. Results are presented as survival probabilities based on Kaplan-Meier survival estimates. RESULTS: Patients (N = 300) were 58% male, with a mean age of 68 ± 10 years. Diabetes was present in 56%, 80% presented with claudication, and 20% with rest pain. Lesions included ISR of the SFA in 68%, SFA-popliteal in 26%, and popliteal arteries in 7%. The mean lesion length was 17.8 ± 11.8 cm. Lesions were categorized as occlusions in 43% (mean occluded length, 16 ± 10 cm). TASC type was A (17%), B (29%), C (38%), and D (15%). Technical success was 99%. Re-stenting was performed in 5% and thrombolysis in 0.6% of patients. Kaplan-Meier estimates for freedom from target lesion revascularization were 90%, 72%, and 62% at 12, 24, and 36 months. Freedom from target vessel revascularization was 88%, 68%, and 59% and freedom from major target limb amputation was 99.6%, 98.9%, and 98.9%, respectively, at 12, 24, and 36 months. Survival was 95%, 89%, and 85% at 12, 24, and 36 months. CONCLUSIONS: This post-market registry-based study shows promising results in treating femoral-popliteal ISR with paclitaxel DCB in comparison to the results of plain balloon angioplasty reported in the literature. These results demonstrate the ability of the SVS VQI to conduct post-market evaluation of peripheral devices in partnership with industry and federal regulators.

Distal embolic protection use during transfemoral carotid artery stenting is associated with improved in-hospital outcomes.

OBJECTIVE: Despite current guidelines recommending the use of distal embolic protection during transfemoral carotid artery stenting (tfCAS) to prevent periprocedural stroke, there remains significant variation in the routine use of distal filters. We sought to assess in-hospital outcomes in patients undergoing tfCAS with and without embolic protection using a distal filter. METHODS: We identified all patients undergoing tfCAS in the Vascular Quality Initiative from March 2005 to December 2021 and excluded those who received proximal embolic balloon protection. We created propensity score-matched cohorts of patients who underwent tfCAS with and without attempted placement of a distal filter. Subgroup analyses of patients with failed vs successful filter placement and failed vs no attempt at filter placement were performed. In-hospital outcomes were assessed using log binomial regression, adjusted for protamine use. Outcomes of interest were composite stroke/death, stroke, death, myocardial infarction (MI), transient ischemic attack (TIA), and hyperperfusion syndrome. RESULTS: Among 29,853 patients who underwent tfCAS, 28,213 (95%) had a filter attempted for distal embolic protection and 1640 (5%) did not. After matching, 6859 patients were identified. No attempted filter was associated with significantly higher risk of in-hospital stroke/death (6.4% vs 3.8%; adjusted relative risk [aRR], 1.72; 95% confidence interval [CI], 1.32-2.23; P < .001), stroke (3.7% vs 2.5%; aRR, 1.49; 95% CI, 1.06-2.08; P = .022), and mortality (3.5% vs 1.7%; aRR, 2.07; 95% CI, 1.42-3.020; P < .001). In a secondary analysis of patients who had failed attempt at filter placement vs successful filter placement, failed filter placement was associated with worse outcomes (stroke/death: 5.8% vs 2.7%; aRR, 2.10; 95% CI, 1.38-3.21; P = .001 and stroke: 5.3% vs 1.8%; aRR, 2.87; 95% CI, 1.78-4.61; P < .001). However, there were no differences in outcomes in patients with failed vs no attempted filter placement (stroke/death: 5.4% vs 6.2%; aRR, 0.99; 95% CI, 0.61-1.63; P = .99; stroke: 4.7% vs 3.7%; aRR, 1.40; 95% CI, 0.79-2.48; P = .20; death: 0.9% vs 3.4%; aRR, 0.35; 95% CI, 0.12-1.01; P = .052). CONCLUSIONS: tfCAS performed without attempted distal embolic protection was associated with a significantly higher risk of in-hospital stroke and death. Patients undergoing tfCAS after failed attempt at filter placement have equivalent stroke/death to patients in whom no filter was attempted, but more than a two-fold higher risk of stroke/death compared with those with successfully placed filters. These findings support current Society for Vascular Surgery guidelines recommending routine use of distal embolic protection during tfCAS. If a filter cannot be placed safely, an alternative approach to carotid revascularization should be considered.

Relationship between WIfI stage and quality of life at revascularization in the BEST-CLI trial.

OBJECTIVE: The WIfI (Wound, Ischemia, foot Infection) stage measures the extent of wounds, ischemia, and foot infection in patients with chronic limb threatening ischemia (CLTI) and has been associated with the risk of major amputation. Patients with CLTI have impaired health-related quality of life (HRQoL), which can be multifactorial. We hypothesized that the severity of the limb threat (WIfI stage) would be associated with poor HRQoL among patients with CLTI presenting for revascularization. METHODS: The dataset of the BEST-CLI (best endovascular versus best surgical therapy in patients with CLTI) trial, a prospective, randomized trial comparing open and endovascular revascularization strategies, was queried for HRQoL assessments at patient enrollment. The HRQoL assessments included (1) Vascular Quality of Life; (2) 12-item short form survey (SF-12), containing the utility index score (short-form six-dimension R2 utility index, incorporating physical, emotional, and mental well-being) and mental and physical components; and (3) the EQ-5D. Multivariable regression analysis was used to identify the independent associations with the baseline HRQoL assessments. RESULTS: A total of 1568 patients with complete WIfI data were analyzed, of whom 71.5% were men. The WIfI distribution was 35.5% with stage 4, 29.6% with stage 3, 28.6% with stage 2, and 6.3% with stage 1. Patients presenting with WIfI stage 4, compared with stage 1 to 3, were more often men (74.9% vs 69.6%) and current smokers (25.4% vs. 17.6%), had had end-stage renal disease (13.3% vs 8.5%) and diabetes (83.6% vs 60.2%), were not independently ambulatory (56.8% vs 38.5%), and had had higher median morbidity scores (4 vs 3; P < .05 for all). On multivariable analysis, WIfI stage 4, compared with stage 1 to 3, was associated with lower SF-12 mental component scale scores (estimate, -2.43; 95% confidence interval, -3.73 to -1.13; P < .001) and short-form six-dimension R2 utility index scores (estimate, -0.02; 95% confidence interval, -0.03 to 0.001; P = .04). The WIfI stage was not independently associated with the baseline Vascular Quality of Life, SF-12 physical component scale, or EQ-5D assessments. CONCLUSIONS: WIfI stage was independently associated with poorer quality of life because of mental, rather than physical, health for patients with CLTI. Clinicians should be aware of the burden of mental stress borne by those with the greatest limb impairment.

Surgery or Endovascular Therapy for Chronic Limb-Threatening Ischemia.

BACKGROUND: Patients with chronic limb-threatening ischemia (CLTI) require revascularization to improve limb perfusion and thereby limit the risk of amputation. It is uncertain whether an initial strategy of endovascular therapy or surgical revascularization for CLTI is superior for improving limb outcomes. METHODS: In this international, randomized trial, we enrolled 1830 patients with CLTI and infrainguinal peripheral artery disease in two parallel-cohort trials. Patients who had a single segment of great saphenous vein that could be used for surgery were assigned to cohort 1. Patients who needed an alternative bypass conduit were assigned to cohort 2. The primary outcome was a composite of a major adverse limb event - which was defined as amputation above the ankle or a major limb reintervention (a new bypass graft or graft revision, thrombectomy, or thrombolysis) - or death from any cause. RESULTS: In cohort 1, after a median follow-up of 2.7 years, a primary-outcome event occurred in 302 of 709 patients (42.6%) in the surgical group and in 408 of 711 patients (57.4%) in the endovascular group (hazard ratio, 0.68; 95% confidence interval [CI], 0.59 to 0.79; P<0.001). In cohort 2, a primary-outcome event occurred in 83 of 194 patients (42.8%) in the surgical group and in 95 of 199 patients (47.7%) in the endovascular group (hazard ratio, 0.79; 95% CI, 0.58 to 1.06; P = 0.12) after a median follow-up of 1.6 years. The incidence of adverse events was similar in the two groups in the two cohorts. CONCLUSIONS: Among patients with CLTI who had an adequate great saphenous vein for surgical revascularization (cohort 1), the incidence of a major adverse limb event or death was significantly lower in the surgical group than in the endovascular group. Among the patients who lacked an adequate saphenous vein conduit (cohort 2), the outcomes in the two groups were similar. (Funded by the National Heart, Lung, and Blood Institute; BEST-CLI ClinicalTrials.gov number, NCT02060630.).

Female Sex is Associated with More Reinterventions after Endovascular and Open Interventions for Intermittent Claudication.

BACKGROUND: Intermittent claudication (IC) is a commonly treated vascular condition. Patient sex has been shown to influence outcomes of interventions for other vascular disorders; however, whether outcomes of interventions for IC vary by sex is unclear. We sought to assess the association of patient sex with outcomes after IC interventions. METHODS: The Vascular Quality Initiative was queried from 2010-2020 for all peripheral endovascular interventions (PVI), infra-inguinal bypasses (IIB), and supra-inguinal bypasses (SIB) for any degree IC. Univariable and multivariable analyses compared peri-operative and long-term outcomes by patient sex. RESULTS: There were 24,701 female and 40,051 male patients undergoing PVI, 2,789 female and 6,525 male patients undergoing IIB, and 1,695 female and 2,370 male patients undergoing SIB for IC. Guideline-recommended pre-operative medical therapy differed with female patients less often prescribed aspirin for PVI (73.4% vs. 77.3%), IIB (71.5% vs. 74.8%), and SIB (70.9% vs. 74.3%) or statins for PVI (71.8% vs. 76.7%) and IIB (73.1% vs. 76.0%) (all P < 0.05). Female compared with male patients had lower 1-year reintervention-free survival after PVI (84.4% ± 0.3% vs. 86.3% ± 0.2%, P < 0.001), IIB (79.0% ± 0.9% vs. 81.2% ± 0.6%, P = 0.04), and SIB (89.4% ± 0.9% vs. 92.6% ± 0.7%, P = 0.005), but similar amputation-free survival and survival across all procedures. Multivariable analysis confirmed that female sex was associated with increased 1-year reintervention for PVI (HR 1.16, 95% CI 1.09-1.24, P < 0.001), IIB, (HR 1.16, 95% CI 1.03-1.31, P = 0.02), and SIB (HR 1.60, 95% CI 1.20-2.13, P = 0.001). CONCLUSIONS: Female patients undergoing interventions for IC were less often pre-operatively medically optimized than male patients, though the difference was small. Furthermore, female sex was associated with more reinterventions after interventions. Interventionists treating female patients should increase their efforts to maximize medical therapy. Future research should clarify reasons for poorer intervention durability in female patients.

Not all risk scores are created equal: A comparison of risk scores for abdominal aortic aneurysm repair in administrative data and quality improvement registries.

OBJECTIVE: Accurate and contemporary prognostic risk prediction is essential to inform clinical decision-making surrounding abdominal aortic aneurysm (AAA) care. Therefore, we validated and compared three different in-hospital mortality risk scores in one administrative and two quality improvement registries. METHODS: We included patients who had undergone elective AAA repair from 2012 to 2015 in the National Inpatient Sample (NIS), Vascular Quality Initiative (VQI; excluding the New England region), and the National Surgical Quality Improvement Program (NSQIP) datasets to validate three risk scores: Medicare, the Vascular Study Group of New England (VSGNE), and Glasgow Aneurysm Score (GAS). The receiver operating characteristic area under the curve (AUC) of all risk scores was calculated, and their discrimination was compared within a dataset using the Delong test and between datasets using a Z test. We constructed graphic calibration curves for the Medicare and VSGNE risk scores and compared the calibration using an integrated calibration index, which indicates the weighted average of the absolute difference between the calibration curve and the diagonal line of perfect calibration. RESULTS: We identified a total of 25,461 NIS, 18,588 VQI, and 8051 NSQIP patients who had undergone elective open or endovascular AAA repair. Overall, the Medicare risk score was more likely to overestimate mortality in the quality improvement registries and the VSGNE risk score underestimated mortality in all the databases. After endovascular AAA repair, the Medicare risk score had a higher AUC in the NIS than in the GAS (P < .001) but not compared with the VSGNE risk score (P = .54). The VSGNE risk score was associated with a significantly higher receiver operating characteristic AUC compared with the Medicare (P < .001) and GAS (P < .001) risk scores in the VQI registry. Also, the VSGNE risk score showed improved calibration compared with the Medicare risk score across all three databases (P < .001 for all). After open repair, the Medicare risk score showed improved calibration compared with the VSGNE risk score in the NIS (P < .001). However, in the VQI registry, the VSGNE risk score compared with the Medicare risk score had significantly better discrimination (P = .008) and calibration (P < .001). CONCLUSIONS: Overall, the VSGNE risk score performed best in the quality improvement registries but underestimated mortality. However, the Medicare risk score demonstrated better calibration in the administrative dataset after open repair. Although the VSGNE risk score appeared to perform better in the quality improvement registries, its overly optimistic mortality estimates and its reliance on detailed anatomic and clinical variables reduces its broader applicability to other databases.

Effect of ischemia-reperfusion on outcomes after open mesenteric bypass for chronic mesenteric ischemia.

OBJECTIVE: Significant physiologic perturbations can occur in patients with chronic mesenteric ischemia (CMI) undergoing open mesenteric bypass (OMB). These events have frequently been attributed to ischemia-reperfusion events and have been directly implicated in the occurrence of multiple organ dysfunction (MOD). Scoring systems (MOD score [MODS] and sequential organ failure assessment [SOFA]) have been derived within the critical care field to provide a composite metric for these pathophysiologic changes. The purpose of the present study was to describe the early pathophysiologic changes that occur after OMB for CMI and determine whether these are predictive of the outcomes. METHODS: Patients with CMI who had undergone elective OMB from 2002 to 2018 at a single institution were reviewed. Changes in the hemodynamic, pulmonary, hepatic, renal, and hematologic parameters in the first 96 hours postoperatively were analyzed. The MODSs and SOFA scores were calculated. Cox regression was used to determine the association of the MODSs and SOFA scores with the outcomes. RESULTS: The use of OMB was analyzed for 72 patients (age, 66 ± 11 years; 68% women; body mass index, 23.8 ± 6 kg/m2; 48 ± 34-lb weight loss in 59%). Previous mesenteric stent placement or bypass had been performed in 39% [stenting in 21; bypass in 8; (one patient had both)]. An antegrade configuration (93%) was most common (retrograde configuration, 7%), with revascularization of the superior mesenteric artery/celiac vessels in 85% (superior mesenteric artery only in 15%). Postoperative pathophysiologic and metabolic changes were common, and the mean MODSs and SOFA scores were 3.6 ± 2.4 (range, 1-10) and 4.0 ± 2.7 (range, 1-13), respectively. The median length of stay was 14 days (interquartile range, 9-21). The 30-day mortality was 4% (n = 3) and in-hospital morbidity was 53% (n = 38; gastrointestinal, 25%; infectious, 22%; cardiac, 18%; pulmonary, 18%; renal, 11%). The clinical follow-up period was 16 ± 20 months. The MODSs and SOFA scores correlated linearly with overall mortality (MODS: odds ratio [OR], 1.4; 95% confidence interval [CI], 1.2-1.7; P < .01; SOFA score: OR, 1.4; 95% CI, 1.2-1.7; P < .01 per unit), with a score of ≥5 the inflection point most predictive of mortality (MODS: OR, 3.9; 95% CI, 1.6-9.9; P ≤ .01; SOFA score: OR, 2.8; 95% CI, 1.2-6.6; P = .02). The 1- and 3-year primary bypass patency and freedom from reintervention was 91% ± 5% and 83% ± 7%, respectively, with no association with the MODSs or SOFA scores. The 1- and 3-year survival was 86% ± 4% and 71% ± 6% with significantly worse outcomes for patients with higher MODSs and/or SOFA scores. CONCLUSIONS: Most CMI patients undergoing OMB will experience significant metabolic derangements resulting from sequelae of the ischemia-reperfusion phenomenon postoperatively. These can be objectively assessed in the early postoperative period using simply applied scoring systems to reliably predict the early and long-term outcomes. A derivation of the MODS and/or SOFA score after OMB for CMI can identify the most vulnerable patients at the greatest risk of mortality.

Remodeling, Reintervention, and Survival After Endovascular Repair of Chronic Type B Dissection.

BACKGROUND: The efficacy of thoracic endovascular aortic repair (TEVAR) of chronic type B aortic dissection (cTBAD) is controversial. Only limited evidence describes temporal anatomic changes after TEVAR for cTBAD and their relationship to outcomes. We sought to investigate early aortic remodeling events after TEVAR for cTBAD with thoracic aneurysm and determine the association with reintervention and survival. METHODS: Records from 95 cTBAD patients undergoing TEVAR from 2005 to 2017 were reviewed. Using 3-dimensional centerline analysis, anatomic phenotyping of the thoracoabdominal aorta was performed. Reverse aortic remodeling (RAR) was defined by a ≥5-mm reduction in maximal thoracic aortic diameter. Kaplan-Meier analysis estimated freedom from reintervention and survival. RESULTS: Visceral segment dissection involvement was present in 89% of patients (n = 85), and the mean preoperative thoracic diameter was 63 mm (SD, 10). Complete thoracic false lumen thrombosis occurred in 71% of patients (n = 67), whereas abdominal false lumen thrombosis was documented in 60% (n = 57) by 6 months. RAR occurred in 41%. Aortic reintervention rate was 39% (n = 37). The 1- and 3-year freedom from reintervention was significantly higher in subjects experiencing early RAR (log-rank P = .02), but reintervention did not impact overall survival (log-rank P = .9). Similarly, overall survival was similar between patients with or without RAR (log-rank P = .4). CONCLUSIONS: Early RAR is associated with decreased rates of reintervention; however, overall survival is not impacted by these changes. TEVAR for cTBAD results in a high rate of reintervention, which mandates vigilant surveillance protocols.

Association between surgeon case volume and years of practice experience with open abdominal aortic aneurysm repair outcomes.

BACKGROUND: Widespread adoption of endovascular aneurysm repair has led to a consequential decline in the use of open aneurysm repair (OAR). This evolution has had significant ramifications on vascular surgery training paradigms and contemporary practice patterns among established surgeons. Despite being the subject of previous analyses, the surgical volume-outcome relationship has remained a focus of controversy. At present, little is known about the complex interaction of case volume and surgeon experience with patient selection, procedural characteristics, and postoperative complications of OAR. The purpose of the present analysis was to examine the association between surgeon annual case volume and years of practice experience with OAR. METHODS: All infrarenal OARs (n = 11,900; elective, 70%; nonelective, 30%) included in the Society for Vascular Surgery Vascular Quality Initiative from 2003 to 2019 were examined. Surgeon experience was defined as years in practice after training. The experience level at repair was categorized chronologically (≤5 years, n = 1667; 6-10 years, n = 1887; 11-15 years, n = 1806; ≥16 years, n = 6540). The annual case volume was determined by the number of OARs performed by the surgeon annually (median, five cases). Logistic regression was used to perform risk adjustment of the outcomes across surgeon experience and volume (five or fewer vs more than five cases annually) strata for in-hospital major complications and 30-day and 1-year mortality. RESULTS: Practice experience had no association with unadjusted mortality (30-day death: elective, P = .2; nonelective, P = .3; 1-year death: elective, P = .2; nonelective, P = .2). However, more experienced surgeons had fewer complications after elective OAR (25% with ≥16 years vs 29% with ≤5 years; P = .004). A significant linear correlation was identified between increasing surgeon experience and performance of a greater proportion of elective OAR (P-trend < .0001). Risk adjustment (area under the curve, 0.776) revealed that low-volume (five or fewer cases annually) surgeons had inferior outcomes compared with high-volume surgeons across the experience strata for all presentations. In addition, high-volume, early career surgeons (≤5 years' experience) had outcomes similar to those of older, low-volume surgeons (P > .1 for all pairwise comparisons). Early career surgeons (≤5 years) had operated on a greater proportion of elective patients with American Society of Anesthesiologists class ≥4 (35% vs 30% [≥16 years' experience]; P = .0003) and larger abdominal aortic aneurysm diameters (mean, 62 vs 59 mm [≥16 years' experience]; P < .0001) compared with all other experience categories. Similarly, the use of a suprarenal cross-clamp occurred more frequently (26% vs 22% [≥16 years' experience]; P = .0009) but the total procedure time, estimated blood loss, and renal and/or visceral ischemia times were all greater for less experienced surgeons (P-trend < .0001). CONCLUSIONS: Annual case volume appeared to be more significantly associated with OAR outcomes compared with the cumulative years of practice experience. To ensure optimal OAR outcomes, mentorship strategies for "on-boarding" early career, as well as established, low-volume, aortic aneurysm repair surgeons should be considered. These findings have potential implications for widespread initiatives surrounding regulatory oversight and credentialing paradigms.

Contemporary management and outcomes of complex vascular surgical groin wound infections.

OBJECTIVE: Vascular surgical groin wound infection (VS-GWI) has multiple causes and frequently is manifested as a limb- or life-threatening problem, resulting in significant morbidity and mortality. For patients undergoing operative extirpation, in situ repair, extra-anatomic bypass, or ligation can be used; however, limited data exist describing comparative results of the different operative choices or conduit subtypes. Therefore, we sought to describe our experience with management of VS-GWI and to detail outcomes of the different strategies. METHODS: Patients (2003-2017) undergoing surgical treatment of VS-GWI (Szilagyi grade III) secondary to primary infectious arteritis or infected pseudoaneurysm after percutaneous intervention as well as previous prosthetic graft placement were reviewed. The primary end point was major adverse limb events (MALEs; major amputation, graft occlusion, or unplanned reintervention). Secondary end points included 30-day mortality, wound healing, amputation-free survival (AFS), and all-cause mortality. Cox proportional hazards modeling was used to determine relative risk of end points; Kaplan-Meier methodology was employed to estimate freedom from outcomes. RESULTS: There were 149 patients (age, 65 ± 11 years; body mass index, 27 ± 6 kg/m2; 70% male; 32% diabetes) identified, of whom 120 (81%) had unilateral and 29 (19%) had bilateral VS-GWI. Indications included infected prosthetic bypass (88% [n = 131]; infrainguinal, 107; suprainguinal, 24) and primary infectious femoral artery complications (12% [n = 18]). A majority underwent single-stage operations (87% [n = 129]). In situ reconstruction occurred in 87% (n = 129); 9% (n = 13) underwent ligation, and 6% (n = 7) received extra-anatomic revascularization. Autogenous conduit was used most commonly (68% [n = 101/149]; 88% single stage), of which 81% (n = 80) were femoral vein. The remaining patients received cadaveric (15% [n = 23]; 87% single stage) or prosthetic (8% [n=12]; 67% single stage) grafts. Adjunctive myocutaneous flap was used in 37% (n = 54). Length of stay was 19 ± 15 days and 30-day mortality was 7% (n = 10), with no difference between conduit repair types. All femoral wounds healed (mean follow-up, 17 ± 11 months); however, 33% (n = 49) underwent reoperation (unplanned graft reintervention, 33%; graft occlusion, 16%; wound débridement, 15%; major amputation, 11%). Reinfection occurred in 17% (n = 27), with no difference between groups. MALE rate was 22% (n = 33; most were arterial reinterventions, 19%), with no difference in single-stage vs multistage, in situ vs extra-anatomic, or autogenous vs nonautogenous conduit strategies Predictors of MALE included younger age (hazard ratio [HR], 1.6 per decade; 95% confidence interval [CI], 1.1-2.5; P = .02) and lower body mass index (<25 kg/m2; HR, 1.6 per BMI category; 95% CI, 1.1-2.5; P = .02). Overall, 1- and 3-year freedom from MALE, AFS, and survival were as follows: MALE, 74% ± 5% and 63% ± 6%; AFS, 68% ± 4% and 58% ± 5%; survival, 78% ± 3% and 70% ± 4%. Autogenous conduit use was associated with better survival (HR, 0.5; 95% CI, 0.3-0.8; 1-year: 83% ± 4% vs nonautogenous, 78% ± 4%; 3-year: 68% ± 8% vs 53% ± 9%; log-rank, P = .006). CONCLUSIONS: An individualized approach to operative strategy and conduit choice leads to comparable outcomes in this challenging group of patients. VS-GWI can be safely managed with in situ, autogenous reconstruction in a majority of patients with acceptable mortality, excellent wound healing rates, and improved overall survival. However, a significant proportion of patients experience reinfection and MALEs, the preponderance of which are arterial reintervention, mandating need for close follow-up and graft surveillance.

A comparison of administrative data and quality improvement registries for abdominal aortic aneurysm repair.

OBJECTIVE: Databases are essential in evaluating surgical outcomes and gauging the implementation of new techniques. However, there are important differences in how data from administrative databases and surgical quality improvement (QI) registries are collected and interpreted. Therefore, we aimed to compare trends, demographics, and outcomes of open and endovascular abdominal aortic aneurysm (AAA) repair in an administrative database and two QI registries. METHODS: We identified patients undergoing open and endovascular repair of intact and ruptured AAAs between 2012 and 2015 within the National Inpatient Sample (NIS), the National Surgical Quality Improvement Program (NSQIP), and the Vascular Quality Initiative (VQI). We described the differences and trends in overall AAA repairs for each data set. Moreover, patient demographics, comorbidities, mortality, and complications were compared between the data sets using Pearson χ2 test. RESULTS: A total of 140,240 NIS patients, 10,898 NSQIP patients, and 26,794 VQI patients were included. Ruptured repairs composed 8.7% of NIS, 11% of NSQIP, and 7.9% of VQI. Endovascular aneurysm repair (EVAR) rates for intact repair (range, 83%-84%) and ruptured repair (range, 51%-59%) were similar in the three databases. In general, rates of comorbidities were lower in NIS than in the QI registries. After intact EVAR, in-hospital mortality rates were similar in all three databases (NIS 0.8%, NSQIP 1.0%, and VQI 0.8%; P = .06). However, after intact open repair and ruptured repair, in-hospital mortality was highest in NIS and lowest in VQI (intact open: NIS 5.4%, NSQIP 4.7%, and VQI 3.5% [P < .001]; ruptured EVAR: NIS 24%, NSQIP 20%, and VQI 16% [P < .001]; ruptured open: NIS 36%, NSQIP 31%, and VQI 26% [P < .001]). After stratification by intact and ruptured presentation and repair strategy, several discrepancies in morbidity rates remained between the databases. Overall, the number of cases in NSQIP represents 7% to 8% of the repairs in NIS, and the number of cases in VQI grew from 12% in 2012 to represent 23% of the national sample in 2015. CONCLUSIONS: NIS had the largest number of patients as it represents the nationwide experience and is an essential tool to evaluate trends over time. The lower in-hospital mortality seen in NSQIP and VQI questions the generalizability of the studies that use these QI registries. However, with a growing number of hospitals engaging in granular QI initiatives, these QI registries provide a valuable resource to potentially improve the quality of care provided to all patients.

Editor's Choice - Protamine Reduces Serious Bleeding Complications Associated with Carotid Endarterectomy in Asymptomatic Patients without Increasing the Risk of Stroke, Myocardial Infarction, or Death in a Large National Analysis.

OBJECTIVE: Controversy persists regarding the use of protamine during carotid endarterectomy (CEA), despite real world evidence to support its use. The purpose of this study was to determine the impact of protamine reversal of heparin anticoagulation on the outcome of CEA in the USA. METHODS: A prospective national registry (Society for Vascular Surgery Vascular Quality Initiative) of 72 787 patients undergoing elective asymptomatic CEA by 1879 surgeons from 316 centres in the USA and Canada from 2012 to 2018 was reviewed. Protamine use varied by both surgeon (20% rare use [< 10%], 30% variable use [11%-79%], 50% routine use [> 80% cases]) and geographical region (44% vs. 96%). Temporal trends in protamine use were also determined. End points included post-operative re-operation for bleeding, as well as potential protamine related thrombotic complications, including stroke, death, and myocardial infarction (MI). Predictors of end points were determined by multivariable logistic regression. Propensity matching was additionally used to control for differences between groups. RESULTS: Of the 72 787 patients who underwent CEA, 69% received protamine, while 31% did not. Protamine use increased over time from 60% (2012) to 73% (2018). In total, 378 patients (0.7%) in the protamine treated group underwent re-operation for bleeding vs. 342 patients (1.4%) in the untreated cohort (p < .001). Protamine use did not affect the rate of MI (0.7% vs. 0.8%; p = .023), stroke (1.1% vs. 1.0%; p = .20), or in hospital death (0.2% vs. 0.2%; p = 0.70) between treated and untreated patients, respectively. On multivariable analysis, protamine use was independently associated with reduced risk of re-operation for bleeding (odds ratio 0.5, 95% confidence interval 0.39-0.55; p < .001). Independent of protamine exposure, the consequences of a return to the operating room (RTOR) for bleeding were statistically significant, with a sevenfold increase in MI (RTOR 4.9% vs. no RTOR 0.7%; p < .001), an eightfold increase in stroke (RTOR 7.2% vs. no RTOR 0.9%; p < .001), and a 13 fold increase in death (RTOR 2.4% vs. no RTOR 0.2%; p < .001). CONCLUSION: Protamine reduces serious bleeding complications at the time of CEA without increasing the risk of MI, stroke, or death, in this large North American analysis. Based on this and previous regional work regarding protamine use in CEA, it is believed that there is now sufficient evidence to support its routine use, and it should be considered as a benchmark for quality during CEA.

Association of hospital volume with patient selection, risk of complications, and mortality from failure to rescue after open abdominal aortic aneurysm repair.

OBJECTIVE: The association of higher hospital volume with lower mortality after open abdominal aortic aneurysm (OAAA) repair is well known; however, the underlying mechanism for improved outcomes is poorly understood. Better patient selection, lower risk of complications, and improved ability to rescue patients after adverse events are assumed mechanisms, but few data exist to validate this hypothesis. The purpose of this analysis was to determine the association of hospital volume with patient selection, incidence of complications, and failure to rescue (FTR) after adverse events resulting from OAAA repair. METHODS: The Vizient (Irving, Tex) database (>95% of all academic hospitals) was reviewed for OAAA repairs (elective, n = 2827; nonelective, n = 1622) performed from 2012 to 2014. Presentation type (elective vs nonelective) was considered in all analyses. Elixhauser comorbidity index and van Walraven weighted scores were assigned to patients and volume-outcome relationships explored. By use of logistic regression, risk-adjusted complications (including preventable complications; Agency for Healthcare Research and Quality patient safety indicators [PSIs]) and FTR rates were determined. Predicted risk scores were assigned to delineate hospital volume association with these outcomes. RESULTS: Overall, no relationship between hospital volume and composite patient comorbidity severity score was identified (Elixhauser comorbidity index and van Walraven weighted scores: Pearson [ρ, 0.02], P = .2; [ρ, -0.01], P = .4; Spearman correlation coefficient [ρ, 0.02], P = .4; [ρ, -0.02], P = .2). The lack of correlation persisted in considering elective vs nonelective status. However, for elective cases, differences in specific comorbidities were noted because high-volume hospitals were more likely to repair patients with a history of peripheral vascular disease (P = .01), diabetes (P = .07), obesity (P = .004), and alcohol abuse (P = .05). Lower volume hospitals more frequently repaired patients with hypothyroidism (P = .05), fluid and electrolyte disorders (P = .007), and chronic blood loss anemia (P = .05). No specific individual comorbidity differences were detected for nonelective cases. In examining hospital volume effects on the likelihood for development of any complication (45%), PSIs (12%), and FTR (9%), a significant risk reduction was noted in high-volume institutions. Specifically, a nonlinear relationship between hospital volume and risk of any complication (P = .0004), PSI (P = .0004), and FTR (P =. 0003) was present. In exploring the risk of specific complications or PSI events, greater hospital volume was strongly correlated to a lower likelihood of multiple adverse outcomes. CONCLUSIONS: Although high-volume institutions performing OAAA repair do not necessarily operate on patients with more comorbidities, there are important differences in the patients selected compared with lower volume hospitals. The risk for development of multiple specific postoperative complications as well as for preventable adverse events preceding FTR is significantly lower in high-volume centers. These findings provide benchmarks for multiple selected quality indicators and further support national initiatives to incentivize regionalization of OAAA care.

Surgeon experience association with patient selection and outcomes after open abdominal aortic aneurysm repair.

BACKGROUND: Growing calls for guidelines advocating minimum annual case volumes for surgeon credentialing remain controversial. Although most attention to date has focused on the impact of obligatory case volume, less attention has been devoted to the more complex association between surgeon years of independent practice experience and procedure outcomes after open abdominal aortic aneurysm repair (OAR). Therefore, the purpose of this study was to explore the association of surgeon experience with case selection and real-world outcomes after OAR. METHODS: All Society for Vascular Surgery-Vascular Quality Initiative infrarenal and juxtarenal OARs (n = 11,900; 71% elective; 29% nonelective) from 2003 to 2019 were examined. Surgeon experience was defined by years in practice after training completion. Experience level at time of repair was categorized (≤5 years, n = 1048; 6-10 years, n = 1309; 11-15 years, n = 1244; and ≥16 years, n = 4772) and intergroup univariate comparisons were made. Logistic regression identified independent predictors of complications, 30-day death, and 1-year mortality. Models were constructed with or without surgeon experience strata to determine association with outcomes. RESULTS: Increasing surgeon experience was associated with performing greater proportions of elective procedures, whereas less experienced surgeons had disproportionate exposure to nonelective operations (elective, 73% ≥16 years vs 62% ≤5 years [P < .0001]; nonelective, ≤5 years, 38% vs 27%, ≥16-years [P < .0001]). Among surgeons who perform five or fewer cases per year, the risk of any aggregate major complication after elective OAR decreased significantly as experience increased (P = .0004), although no differences were detected in nonelective cases or among higher volume surgeons. Similarly, the risk of in-hospital death decreased with increasing experience (P = .004), but only among low-volume surgeons performing elective procedures. Comorbidities were similar across all experience strata for both elective and nonelective presentations; however, more experienced surgeons operated on higher proportions of nonelective patients with coronary disease (P = .04). Early career surgeons more frequently operated on patients with American Society of Anesthesiologists IV designation, larger abdominal aortic aneurysm diameters and used suprarenal/celiac cross-clamps more frequently than later career surgeons. The 1-year survival after elective and nonelective OAR was not impacted by surgeon experience (Ptrend > .15 for all comparisons). CONCLUSIONS: Increasing surgeon years of practice experience correlated significantly with a reduced risk of developing multiple postoperative complications, including postoperative death in the elective setting. Surgeons within their first 5 years of practice are exposed to greater proportions of nonelective cases but seem to have similar outcomes after these repairs compared with surgeons with more experience. Notably, surgeons in their first 5 years of practice operate on more complex elective patients as underscored by higher aggregate comorbidity scores, larger aneurysm diameters, and need for suprarenal aortic cross-clamping. These data have important implications on training paradigms, faculty recruitment, and the organization of mentorship when on boarding new surgeons.

Five-year survival following endovascular repair of ruptured abdominal aortic aneurysms is improving.

OBJECTIVE: Increasing experience and improving technology have led to the expansion of endovascular aneurysm repair (EVAR) for ruptured abdominal aortic aneurysms (AAA). We investigated whether the 5-year survival after both EVAR and open repair for ruptured AAA changed over the last 14 years. METHODS: We identified repairs for ruptured infrarenal AAA within the Vascular Quality Initiative registry between 2004 and 2018. We compared the 5-year survival of both EVAR and open repair between the early (2004-2012) and late (2013-2018) cohorts. In addition, we compared EVAR with open repair in the early and late cohorts. We used propensity score modeling to create matching cohorts for each analysis. Kaplan-Meier analysis was used to estimate survival proportions and univariate Cox proportional hazards analysis was used to compare differences in hazard of mortality in the matched cohorts. RESULTS: We identified 4638 ruptured AAA repairs. This included 409 EVARs in the early cohort and 2250 in the late cohort, as well as 558 open repairs in the early cohort and 1421 in the late cohort. Propensity matching resulted in 366 matched pairs of late vs early EVAR and 391 matched-pairs of late vs early open repair. When comparing EVAR with open repair, propensity matching resulted in 277 matched pairs of early EVAR versus open, and 1177 matched pairs of late EVAR versus open. In matched EVAR patients, 5-year survival was higher in the late cohort (63% vs 49%; hazard ratio [HR], 0.77; 95% confidence interval [CI], 0.61-0.97; P = .027), whereas there was no difference between matched late vs early for open repair patients (52% vs 59%; HR, 1.04; 95% CI, 0.85-1.28; P = .69). In the early cohort, there was no survival difference between EVAR and open repair (51% vs 46%; HR, 0.88; 95% CI, 0.69-1.11; P = .28). However, in the late cohort EVAR was associated with higher survival compared with open repair (63% vs 54%; HR, 0.69; 95% CI, 0.60-0.79; P < .001). CONCLUSIONS: The 5-year survival after EVAR for ruptured AAA has improved over time, whereas survival after open repair remained constant. Consequently, the relative survival benefit of EVAR over open repair has increased over time, which should encourage further adoption of EVAR for ruptured AAA.

National incidence, mortality outcomes, and predictors of spinal cord ischemia after thoracic endovascular aortic repair.

OBJECTIVE: Spinal cord ischemia (SCI) is a dreaded complication of thoracic endovascular aortic repair (TEVAR). There are limited national data describing the incidence and influence of in-hospital SCI recovery on survival. Moreover, no robust preoperative SCI risk assessment models currently exist. The purpose of this analysis was to analyze the Vascular Quality Initiative to determine the national incidence, survival association, and preoperative predictors of SCI after TEVAR. METHODS: All Vascular Quality Initiative TEVAR procedures (June 2014-June 2019) were reviewed. The primary end point was development of in-hospital SCI, defined as any new neurologic deficit or paralysis not attributable to intracranial disease. Secondary end points were disease-specific SCI rates and long-term out-of-hospital survival. Functional outcomes (transient vs permanent SCI) were independently determined by treating physicians. Kaplan-Meier analysis and Cox proportional hazards methodology were used to assess the association of SCI with survival. A logistic regression model of candidate preoperative SCI predictors was created, and bootstrapped backward elimination (retaining predictors with ≥50% selection frequency) was used for model reduction. Model fit and performance statistics were validated by adjustment for Efron's optimism. RESULTS: The overall rate of SCI was 3.7% (n = 422/11,473; transient, 1.6% [n = 179]; permanent, 2.1% [n = 243]). Patients who developed any SCI had significantly lower Kaplan-Meier survival estimate compared with those without SCI (1-year survival: SCI, 65%; no SCI, 87%; P < .0001), and patients with permanent SCI had notably worse survival than patients with transient SCI (1-year survival: permanent SCI, 54%; transient SCI, 80%; P < .0001). Disease-specific incidence of any SCI was as follows: aneurysm, 3.4%; dissection, 5.3%; aneurysm from dissection, 4.1%; trauma, 1.1%; penetrating ulceration, 2.4%; intramural hematoma, 5.7%; penetrating ulceration and intramural hematoma, 4.3%; and aortic thrombus, 4.8%. Several factors were selected on multivariable analysis as the most robust preoperative predictors of any SCI, including distal landing zone 5 to zone 10, nonelective case, creatinine concentration >1.38 mg/dL, smoking history, American Society of Anesthesiologists class, adjunctive procedure, nonwhite race, and preoperative hypertension (area under the curve = 0.72; Nagelkerke R2 = 0.06). CONCLUSIONS: SCI is a devastating complication after TEVAR that is associated with worse overall survival, particularly when no functional recovery occurs by hospital discharge. Disease-specific, real-world benchmarks for SCI rates are provided that may inform quality initiatives focused on reducing this complication. Importantly, this analysis is the first description of a preoperative prediction model derived from national data for determining SCI risk after TEVAR. These predictors should be used to identify high-risk patients to balance the risk of SCI and its associated increased short-term mortality with the risk of the underlying disease. Furthermore, all available adjunctive measures should be implemented in these high-risk patients to reduce risk of SCI.

Comparative outcomes of open, hybrid, and fenestrated branched endovascular repair of extent II and III thoracoabdominal aortic aneurysms.

OBJECTIVE: Open repair of extent II and III thoracoabdominal aortic aneurysms (TAAA) is associated with substantial morbidity. Alternative strategies, such as hybrid operations combining proximal thoracic endovascular aortic repair with either staged open distal TAAA repair or visceral debranching (hybrid), as well as fenestrated/branched endografts (FEVAR), have been increasingly reported; however, benefits of these approaches compared with direct open surgery remain unclear. The purpose of this study was to compare outcomes of these three different strategies in the management of extent II/III TAAA. METHODS: All extent II/III TAAA repairs (2002-2018) for nonmycotic, degenerative aneurysm or chronic dissection at a single institution were reviewed. The primary end point was 30-day mortality. Secondary end points included incidence of spinal cord ischemia (SCI), complications, unplanned re-operation, 90-day readmission, and out-of-hospital survival. To mitigate impact of covariate imbalance and selection bias, intergroup comparisons were made using inverse probability weighted-propensity analysis. Cox regression was used to estimate survival while cumulative incidence was used to determine reoperation risk. RESULTS: One hundred ninety-eight patients (FEVAR, 92; hybrid, 40; open, 66) underwent repair. In unadjusted analysis, compared with hybrid/open patients, FEVAR patients were significantly older with more cardiovascular risk factors, but less likely to have a connective tissue disorder or dissection-related indication. Unadjusted 30-day mortality and complication rates were: 30-day mortality, FEVAR 4%, hybrid 13%, open 12% (P = .01); and complications, FEVAR 36%, hybrid 33%, open 50% (P = .11). Permanent SCI was not different among groups (FEVAR 3%, hybrid 3%, open 6%; P = .64). In adjusted analysis, 30-day mortality risk was greater for open vs FEVAR (hazard ratio, 3.6; 95% confidence interval, 1.4-9.2; P = .01) with no difference for hybrid vs open/FEVAR. There was significantly lower risk of any SCI for open vs FEVAR (hazard ratio, 0.3; 95% confidence interval, 0.09-0.96; P = .04); however, no difference in risk of permanent SCI was detected among the three groups. There was no difference in complications or unplanned reoperation, but open patients had the greatest risk of unplanned 90-day readmission. There was a time-varying effect on survival probability, with open repair having a significant survival disadvantage in the first 1 to 6 months after the procedure compared with hybrid/FEVAR patients (Cox model P = .03), but no difference in survival at 1 and 5 years (1- and 5-year survival: FEVAR, 86 ± 3%, 55 ± 8%; hybrid, 86 ± 5%, 60 ± 11%; open 69 ± 7%, 59 ± 8%; Cox-model P = .10). CONCLUSIONS: Extent II/III TAAA repair, regardless of operative strategy, is associated with significant morbidity risk. FEVAR is associated with the lowest 30-day mortality risk compared with hybrid and open repair when estimates are adjusted for preoperative risk factors. These data support greater adoption of FEVAR as first-line therapy to treat complex TAAA disease in anatomically suitable patients who present electively.

Impact of hospital volume on patient safety indicators and failure to rescue following open aortic aneurysm repair.

OBJECTIVE: Failure to rescue (FTR), a patient safety indicator (PSI) defined, codified, and adjudicated by the Agency for Healthcare Research and Quality, is classified as a preventable inpatient death following major complications. FTR has been reported to be a significant driver of postoperative mortality after open abdominal aortic aneurysm (OAAA) repair. The association between hospital volume (HV) and mortality is well known; however, the mechanisms responsible for these improved outcomes and relative contribution to observed interhospital variation is poorly understood. Similarly, HV influence on specific complications predictive of FTR is unknown; therefore, we sought to determine how HV influences risk and contributes to interhospital variation in PSI events leading to FTR and/or in-hospital mortality after OAAA repair. METHODS: The Vizient database (174 academic/nonacademic hospitals) was queried for all OAAA repairs (elective, n = 2827; nonelective, n = 1622) completed from 2012 to 2014. The primary endpoint was combined FTR and/or in-hospital 30-day mortality. Risk-adjusted rates of complications, Agency for Healthcare Research and Quality-designated PSIs, and FTR were determined. Additional modeling identified PSIs associated with FTR, whereas HV effects on PSIs and FTR were evaluated using mixed-effect models accounting for interhospital variation. Proportion of variation attributable to HV was estimated by contrasting hospital random effect variances in the presence/absence of volume effects. RESULTS: The combined overall FTR/in-hospital 30-day mortality rate was 9.3% (n = 414). For elective and nonelective cases, the overall FTR and 30-day mortality rates were: FTR, 1.6%, 4.9%; and 30-day in-hospital mortality, 3.4%, 17.5%, respectively. HV significantly influenced FTR/30-day in-hospital mortality (P < .0001). FTR/30-day mortality odds for hospitals with 3-year volumes of 50, 100, 150, and 200 cases were 1.4, 2.0, 2.7, and 3.0 times lower, respectively, than hospitals performing ≤25 cases/3 years. The proportion of interhospital variation attributed to HV was greatest for FTR/30-day mortality (62%). Procedural volume accounted for 41% and 38% of interhospital variation in postoperative bleeding and myocardial infarction, respectively. Preoperative predictors of FTR included coagulopathy, arrhythmia (nonelective cases); congestive heart failure, obesity (elective cases); and age, neurological disease, hypertension, and valvular disease (all cases). CONCLUSIONS: OAAA FTR/30-day in-hospital mortality strongly correlated with annual case volume with higher volume centers having the lowest risk. Notably, HV accounted for a significant proportion of the observed variation in FTR and specific complications providing direct evidence for how the volume-outcome relationship may influence perioperative mortality. These findings can inform stakeholders to strategically enable them to implement processes of care directed at the most vulnerable patients that are designed to reduce the likelihood of preventable adverse events and death after OAAA repair. Furthermore, these results underscore the need to regionalize OAAA repair and potentially other complex operations, to HV centers because of their improved ability to rescue patients experiencing complications associated with postoperative mortality.