Publications

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.

OBJECTIVE: Few studies adequately evaluate the impact of wound location on patient outcomes after lower extremity revascularization. Consequently, we evaluated the relationship between lower extremity wound location and long-term outcomes.

METHODS: We reviewed all patients at our institution undergoing any first-time open surgical bypass or percutaneous transluminal angioplasty with or without stenting for tissue loss between 2005 and 2014. We categorized wounds into three distinct groups: forefoot (ie, toes and metatarsal heads), midfoot (ie, dorsal, plantar, lateral, medial surfaces excluding toes, metatarsal heads, or heel), and heel. Limbs with multiple wounds were excluded from analyses. We compared rates of perioperative complications, wound healing, reintervention, limb salvage, amputation-free survival, and survival using χ2, Kaplan-Meier, and Cox regression analyses.

RESULTS: Of 2869 infrainguinal revascularizations from 2005 to 2014, 1126 underwent a first-time revascularization for tissue loss, of which 253 patients had multiple wounds, 197 had wounds proximal to the ankle, 100 had unreliable wound information, and 576 (forefoot, n = 397; midfoot, n = 61; heel, n = 118) fit our criteria and had a single foot wound with reliable information regarding wound specifics. Patients with forefoot, midfoot, and heel wounds had similar rates of coronary artery disease, hypertension, diabetes, and smoking history (all P > .05). Conversely, there were significant differences in patient age (71 vs 69 vs 70 years), prevalence of gangrene (41% vs 5% vs 21%), and dialysis dependence (18% vs 17% vs 30%) (all P < .05). There were no statistically significant differences in perioperative mortality (1.3% vs 4.9% vs 4.2%; P = .06) or postoperative complications among the three groups. Between forefoot, midfoot, and heel wounds, there were significant differences in unadjusted 6-month rates of complete wound healing (69% vs 64% vs 53%), 3-year rates of amputation-free survival (54% vs 57% vs 35%), and survival (61% vs 72% vs 41%) (all P < .05). After adjustment, compared with forefoot wounds, heel wounds were associated with higher rates of incomplete 6-month wound healing (hazard ratio [HR], 1.6; 95% confidence interval [CI], 1.1-2.]), major amputation or mortality (HR, 1.7; 95% CI, 1.1-2.7), and all-cause mortality (HR, 1.8; 95% CI, 1.1-3.0), but not major amputation alone (HR, 2.1; 95% CI, 0.9-4.5). In open surgical bypass-first patients, heel wounds were solely associated with an increased risk of all-cause mortality (HR, 1.7; 95% CI, 1.1-2.8), whereas heel wounds in percutaneous transluminal angioplasty-first patients were associated with an increased risk of incomplete wound healing (HR, 2.2; 95% CI, 1.3-3.7), major amputation or mortality (HR, 2.3; 95% CI, 1.1-5.4), and all-cause mortality (HR, 2.8; 95% CI, 1.1-7.2).

CONCLUSIONS: Heel wounds confer considerably higher short- and long-term morbidity and mortality compared with midfoot or forefoot wounds in patients undergoing any first-time lower extremity revascularization.

OBJECTIVE: The Global Limb Anatomic Staging System (GLASS) was developed as a new anatomic classification scheme to grade the severity of chronic limb threatening ischemia. We evaluated the ability of this anatomic grading system to determine major adverse limb events after lower extremity revascularization.

METHODS: We performed a single-institutional retrospective review of 1060 consecutive patients who had undergone 1180 first-time open or endovascular revascularization procedures for chronic limb threatening ischemia from 2005 to 2014. Using the review of angiographic images, the limbs were classified as GLASS stage 1, 2, or 3. The primary composite outcome was reintervention, major amputation (below- or above-the-knee amputation), and/or restenosis (>3.5× step-up by duplex criteria) events (RAS). The secondary outcomes included all-cause mortality, failure to cross the lesion by endovascular methods, and a comparison between bypass vs endovascular intervention. Kaplan-Meier estimates were used to determine the event rates at 1 and 5 years, and Cox regression analysis was used to adjust for baseline differences among the GLASS stages.

RESULTS: Of all patients undergoing first-time revascularization, imaging studies were available for 1180 procedures (91%) for GLASS grading. Of these procedures, 552 were open bypass (47%) and 628 were endovascular intervention (53%). Compared with GLASS stage 1 disease (n = 267, 23%), stage 2 (n = 367; 31%) and stage 3 (n = 546; 42%) disease were associated with a greater risk of RAS at 1 year (stage 1, 33% vs stage 2, 48% vs stage 3, 53%) and 5 years (stage 1, 45% [reference]; stage 2, 65%; hazard ratio [HR], 1.7; 95% confidence interval [CI], 1.3-2.2; P < .001; stage 3, 69%; HR, 2.3; 95% CI, 1.7-2.9; P < .001). These differences were mainly driven by reintervention and restenosis rather than by major amputation. The 5-year mortality was similar for stage 2 and 3 compared with stage 1 disease (stage 1, 40% [reference]; stage 2, 45%; HR, 1.1; 95% CI, 0.8-1.4; P = .69; stage 3, 49%; HR, 1.2; 95% CI, 1.0-1.6; P = .11). For all attempted endovascular interventions, failure to cross a target lesion increased with advancing GLASS stage (stage 1, 4.5% vs stage 2, 6.3% vs stage 3, 13.3%; P < .01). Compared with open bypass (n = 552; 46.8%), endovascular intervention (n = 628; 53.3%) was associated with a higher rate of 5-year RAS for GLASS stage 1 (49% vs 34%; HR, 1.9; 95% CI, [1.1-3.5; P = .03), stage 2 (69% vs 52%; HR, 1.7; 95% CI, 1.2-2.5; P < .01), and stage 3 (83% vs 61%; HR, 1.5; 95% CI, 1.2-2.0; P < .01) disease.

CONCLUSIONS: For patients undergoing first-time lower extremity revascularization, the GLASS can be used to predict for reintervention and restenosis. Bypass resulted in better long-term outcomes compared with endovascular intervention for all GLASS stages.

OBJECTIVE: The risk of aortic abdominal aneurysm (AAA) rupture increases with an increasing aneurysm diameter. However, the effect of the AAA diameter on late outcomes after aneurysm repair is unclear. Therefore, we assessed the association of a large AAA diameter with late outcomes for patients undergoing open and endovascular AAA repair.

METHODS: We identified all patients who had undergone elective open or endovascular infrarenal aneurysm repair from 2003 to 2016 in the Vascular Quality Initiative linked to Medicare claims for long-term outcomes. A large AAA diameter was defined as a diameter >65 mm. We assessed the 5-year reintervention, rupture, mortality, and follow-up rates. We constructed propensity scores and used inverse probability-weighted Kaplan-Meier estimations and Cox proportional hazard models to identify independent associations between large AAA repair and our outcomes.

RESULTS: Of the 21,119 aneurysm repairs identified, 15.2% were for large AAAs. Of the 21,119 repairs, 19,017 were endovascular and 2102 were open. The large AAA cohort was less likely to have undergone endovascular aneurysm repair (EVAR; 84.9% vs 91%; P < .001), more likely to be older (median age, 76 vs 75 years; P < .001), and were less likely to be women (16.2% vs 21.7%; P < .001). After EVAR, patients with large AAAs had had lower adjusted 5-year freedom from reintervention (73.9% vs 84.6%; P < .001), freedom from rupture (88.5% vs 93.6%; P < .001), survival (58.0% vs 66.4%; P < .001), and freedom from loss to follow-up (77.7% vs 83.3%; P < .001) compared with patients with smaller AAAs. However, after open repair, the adjusted 5-year freedom from reintervention (95.8% vs 93.3%; P = .11), freedom from rupture (97.4% vs 97.8%; P = .32), survival (70.4% vs 74.0%; P = .13), and loss to follow-up (60.5% vs 62.8%; P = .86) were similar to the results for patients with smaller AAAs. For patients with large AAAs, the adjusted 5-year survival was lower after EVAR than that after open repair (55.3% vs 63.7%) but not after smaller AAA repair (67.3% vs 70.6%).

CONCLUSIONS: The 5-year adjusted reintervention, ruptures, mortality, and loss to follow-up rates for patients who had undergone large AAA EVAR were higher than those for patients who had undergone small AAA EVAR and large AAA open repair. Therefore, for patients with large AAAs who are medically fit, open repair should be strongly considered. Furthermore, these findings highlight the necessity for rigorous long-term follow-up after EVAR.

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.

OBJECTIVE: Open surgical repair of juxtarenal abdominal aortic aneurysms (AAA) requires an aortic cross clamp location above at least one renal artery. This study investigated the impact of clamp location on peri-operative outcomes using a United States based nationwide clinical registry.

METHODS: The National Surgical Quality Improvement Program targetted vascular module was used to identify all elective open juxtarenal AAA repairs (2011-2017). Outcomes were compared between clamping above one vs. above both renal arteries, and above one or both renal arteries vs. supracoeliac clamping. The primary outcome was 30 day mortality and secondary outcomes included post-operative renal dysfunction (creatinine increase ≥ 177 μmol/L or new dialysis) and unplanned re-operations. Multivariable logistic regression models were constructed to perform risk adjusted analyses.

RESULTS: A total of 615 repairs were identified, with a clamp location above one renal artery in 42%, above both renal arteries in 40%, and supracoeliac in 18% of cases. Procedures with a clamp location above one vs. above both renal arteries showed no difference in mortality (3.5% vs. 2.1%, p = .34) or renal dysfunction (6.9% vs. 4.9%, p = .34). In contrast, supracoeliac clamping compared with clamping above one or both renal arteries was associated with a higher mortality rate (8.0% vs. 2.8%, p = .023), renal dysfunction (12% vs. 6.0%, p = .017), and unplanned re-operations (24% vs. 10%, p < .001). In the multivariable adjusted models, outcomes were similar between clamping above both vs. above one renal artery, while supracoeliac clamping vs. clamping above one or both renal arteries was associated with higher mortality (odds ratio [OR]: 3.4; 95% CI: 1.3-8.8; p = .013) and unplanned re-operation (OR: 2.4; 95% CI: 1.4-4.1; p = .002).

CONCLUSION: Although there is no difference between clamping above one vs. both renal arteries during open juxtarenal AAA repair, a supracoeliac clamp location is associated with worse peri-operative outcomes. Surgeons should avoid supracoeliac clamping when clamping above one or both renal arteries is technically possible.

OBJECTIVE: Female patients undergoing endovascular aneurysm repair (EVAR) for infrarenal abdominal aortic aneurysms present with more challenging anatomy and historically have worse outcomes compared with men. The Ovation Abdominal Stent Graft platform (Endologix, Irving, Calif) contains a polymer-filled proximal sealing ring and has a low-profile delivery system, potentially beneficial in female patients. We therefore investigated differences in long-term outcomes between men and women treated with this device.

METHODS: We used data collected prospectively in the Effectiveness of Custom Seal with Ovation: Review of the Evidence (ENCORE) database, comprising five trials and the European Post-Market Registry. Anatomic characteristics of the proximal aneurysm neck and iliac arteries were compared between male and female patients. Outcomes were 5-year freedom from type IA and type I/III endoleaks, abdominal aortic aneurysm-related reinterventions, and overall survival. We used Kaplan-Meier analysis to estimate survival proportions and tested univariate differences in survival using log-rank tests. Cox proportional hazards modeling was used to adjust for baseline differences.

RESULTS: We identified 1045 (81%) male and 251 (19%) female patients undergoing EVAR. Female patients were older (mean age, 75 ± 8.4 years vs 73 ± 8.1 years; P < .006). Aneurysm diameter (52 ± 7.5 mm vs 55 ± 9.2 mm; P < .001) and proximal neck diameter (21 ± 3.3 mm vs 23 ± 2.9 mm; P < .001) were smaller in female patients, but adjusted for body surface area, female patients had relatively larger aneurysms and aneurysm necks. Furthermore, female patients presented with shorter proximal necks, smaller iliac artery diameters, more angulated necks, and higher rates of reverse-tapered necks. Five-year freedom from type IA endoleak was similar between men and women (97% vs 96%; P = .38), as was freedom from type I/III endoleaks (91% vs 94%; P = .37) and reinterventions (91% vs 93%; P = .67). Five-year survival was 81% for female patients, similar to the 79% in male patients (P = .55), with one aneurysm-related death in female patients (0.4%) and five in male patients (0.8%; P = .76). Risk-adjusted analyses showed no association between sex and type IA endoleak (hazard ratio [HR], 1.4; 95% confidence interval [CI], 0.6-3.1; P = .41), type I/III endoleak (HR, 1.4; 95% CI, 0.7-2.8; P = .33), reintervention (HR, 1.0; 95% CI, 0.6-2.0; P = .77), and overall mortality (HR, 0.7; 95% CI, 0.4-1.1; P = .14).

CONCLUSIONS: Female patients undergoing EVAR with the Ovation platform presented with substantially more adverse proximal neck characteristics. Despite these differences, 5-year freedom from endoleaks and overall survival did not differ between sexes.

BACKGROUND: Endovascular aneurysm repair (EVAR) is the dominant treatment modality for abdominal aortic aneurysm (AAA). Periprocedural risks are low, and cardiovascular events are the principle determinants of long-term survival. Recently, the concept of endovascular aneurysm sealing (EVAS) has been introduced into clinical investigation. In previous cohort studies, EVAS has been associated with a lower all-cause mortality than expected despite device issues. We used a propensity weighted approach to investigate whether EVAS was associated with lower all-cause mortality after aneurysm repair.

METHODS: We compared 333 patients in the Nellix United States Investigational Device Exemption trial to 15,431 controls from the Vascular Quality Initiative between 2014 and 2016 after applying the exclusion criteria from the investigational device exemption (hemodialysis, creatinine > 2.0 mg/dL, or rupture). We calculated propensity scores and applied inverse probability weighting to compare risk adjusted medium-term survival using Kaplan-Meier and Cox regression.

RESULTS: After weighting, patients treated with the Nellix EVAS system experienced higher 3-year survival than controls from the Vascular Quality Initiative (93% vs. 88%, respectively). This corresponded to a 41% lower risk of mortality for EVAS compared with EVAR (HR 0.59 [0.38-0.92], P = 0.02). Subgroup analysis demonstrated that the association between EVAS and higher survival was strongest in the subgroup of patients with aneurysms over 5.5 cm (P for interaction < 0.001). In this subgroup, EVAS patients experienced half the rate of mortality as those patients treated with EVAR, with 3-year survival of 92% compared with 86% (HR 0.5 [0.3-0.9], P = 0.02).

CONCLUSIONS: In this select group of patients, EVAS was associated with higher medium-term survival than traditional EVAR. Although issues with the device have recently surfaced, this exploratory analysis shows that the concept of sac sealing may hold promise. Further study is needed to confirm this finding and determine whether EVAS is associated with lower rates of cardiovascular events.

OBJECTIVE: Female sex is associated with worse outcomes after infrarenal abdominal aortic aneurysm (AAA) repair. However, the impact of female sex on complex AAA repair is poorly characterized. Therefore, we compared outcomes between female and male patients after open and endovascular treatment of complex AAA.

METHODS: We identified all patients who underwent complex aneurysm repair between 2011 and 2017 in the American College of Surgeons National Surgical Quality Improvement Program targeted vascular module. Complex repairs were defined as those for juxtarenal, pararenal, or suprarenal aneurysms. We compared rates of perioperative adverse events between female and male patients stratified by open AAA repair and endovascular aneurysm repair (EVAR). We calculated propensity scores and used inverse probability-weighted logistic regression to identify independent associations between female sex and our outcomes.

RESULTS: We identified 2270 complex aneurysm repairs, of which 1260 were EVARs (21.4% female) and 1010 were open repairs (30.7% female). After EVAR, female patients had higher rates of perioperative mortality (6.3% vs 2.4%; P = .001) and major complications (15.9% vs 7.6%; P < .001) compared with male patients. In contrast, after open repair, perioperative mortality was not significantly different (7.4% vs 5.6%; P = .3), and the rate of major complications was similar (29.4% vs 27.4%; P = .53) between female and male patients. Furthermore, even though perioperative mortality was significantly lower after EVAR compared with open repair for male patients (2.4% vs 5.6%; P = .001), this difference was not significant for women (6.3% vs 7.4%; P = .60). On multivariable analysis, female sex remained independently associated with higher perioperative mortality (odds ratio [OR], 2.5; 95% confidence interval [CI], 1.3-4.9; P = .007) and major complications (OR, 2.0; 95% CI, 1.3-3.2; P = .002) in patients treated with EVAR but showed no significant association with mortality (OR, 0.9; 95% CI, 0.5-1.6; P = .69) or major complications (OR, 1.1; 95% CI, 0.8-1.5; P = .74) after open repair. However, the association of female sex with higher perioperative mortality in patients undergoing complex EVAR was attenuated when diameter was replaced with aortic size index in the multivariable analysis (OR, 1.9; 95% CI, 0.9-3.9; P = .091).

CONCLUSIONS: Female sex is associated with higher perioperative mortality and more major complications than for male patients after complex EVAR but not after complex open repair. Continuous efforts are warranted to improve the sex discrepancies in patients undergoing endovascular repair of complex AAA.

OBJECTIVE: Limited data exist comparing the transabdominal and retroperitoneal approaches to open abdominal aortic aneurysm (AAA) repair, especially late mortality and laparotomy-related reinterventions and readmissions. Therefore, we compared long-term rates of mortality, reintervention, and readmission after open AAA repair through a transabdominal compared with a retroperitoneal approach.

METHODS: We identified all patients in the Vascular Quality Initiative (VQI) undergoing open AAA repair from 2003 to 2015. Patients with rupture or supraceliac clamp were excluded. We used the VQI linkage to Medicare to ascertain rates of long-term outcomes, including rates of AAA-related and laparotomy-related (ie, hernia, bowel obstruction) reinterventions and readmissions. We used multivariable Cox regression to account for differences in comorbidities, aneurysm details, and operative characteristics.

RESULTS: We identified 1282 patients in the VQI with linkage to Medicare data, 914 (71%) who underwent a transperitoneal approach and 368 (29%) who underwent a retroperitoneal approach. Patients who underwent a retroperitoneal approach were slightly more likely to have preoperative renal insufficiency but were otherwise similar in terms of demographics and comorbidities. They more often had a clamp above at least one renal artery (61% vs 36%; P < .001) and underwent concomitant renal revascularization (9.5% vs 4.3%; P < .001). Patients who underwent a transabdominal approach more often presented with symptoms (14% vs 9.0%; P < .01) and had a femoral distal anastomosis (15% vs 7.1%; P < .001). There was no difference in 5-year survival (62% vs 61%; log-rank, P = .51). However, patients who underwent a transabdominal approach experienced higher rates of repair-related reinterventions and readmissions (5-year: 42% vs 34%; log-rank, P < .01), even after adjustment for demographic and operative differences (hazard ratio, 1.5; 95% confidence interval, 1.1-1.9; P < .01).

CONCLUSIONS: A transabdominal exposure for AAA repair is associated with higher rates of late reintervention and readmission than with the retroperitoneal approach, which should be considered when possible in operative decision-making.