Vascular Quality Initiative assessment of compliance with Society for Vascular Surgery clinical practice guidelines on the care of patients with abdominal aortic aneurysm

Variability in short-term mortality following repair of ruptured abdominal aortic aneurysms across centers and physicians

BACKGROUND

Variation in the care management of repairs for ruptured infrarenal abdominal aortic aneurysms between centers and physicians, such as procedural volumes, may explain differences in mortality outcomes. First, we quantified the center and physician variability associated with 30- and 90-day mortality risk after ruptured open surgical repair (rOSR) and ruptured endovascular aneurysm repair (rEVAR). Second, we explored wheter part of this variability was attributable to procedural volume at the center and physician levels.

METHODS

Two cohorts including rOSR and rEVAR procedures between 2013 and 2019 were analyzed from the Vascular Quality Initiative database. Thirty- and 90-day all-cause mortality rates were derived from linked Medicare claims data. The median odds ratio (MOR) (median mortality risk from low- to high-risk cluster) and intraclass correlation coefficient (ICC) (variability attributable to each cluster) for 30- and 90-day mortality risks associated with center and physician variability were derived using patient-level adjusted multilevel logistic regression models. Procedural volume was calculated at the center and physician levels and stratified by quartiles. The models were sequentially adjusted for volumes, and the difference in ICCs (without vs with accounting for volume) was calculated to describe the center and physician variability in mortality risk attributable to volumes.

RESULTS

We included 450 rOSRs (mean age, 74.5 ± 7.6 years; 23.5% female) and 752 rEVARs (76.4 ± 8.4 years; 26.1% female). After rOSRs, the 30- and 90-day mortality rates were 32.9% and 38.7%, respectively. No variability across centers and physicians was noted (30- and 90-day MORs ≈1 and ICCs ≈0%). Neither center nor physician volume was associated with 30-day (P = .477 and P = .796) or 90-day mortality (P = .098 and P = .559). After rEVAR, the 30- and 90-day mortality rates were 21.3% and 25.5%, respectively. Significant center variability (30-day MOR, 1.82 [95% confidence interval (CI), 1.33-2.22]; ICC, 11% [95% CI, 2%-36%]; and 90-day MOR, 1.76 [95% CI, 1.37-2.09]; ICC, 10% [95% CI, 3%-30%]), but negligeable variability across physicians (30- and 90-day MORs ≈1 and ICCs ≈0%) were noted. Neither center nor physician volume were associated with 30-day (P = .076 and P = .336) or 90-day mortality risk (P = .066 and P = .584). The center variability attributable to procedural volumes was negligeable (difference in ICCs, 1% for 30-day mortality; 0% for 90-day mortality).

CONCLUSIONS

Variability in practice from center to center was associated with short-term mortality outcomes in rEVAR, but not for rOSR. Physician variability was not associated with short-term mortality for rOSR or rEVAR. Annualized center and physician volumes did not significantly explain these associations. Further work is needed to identify center-level factors affecting the quality of care and outcomes for ruptured abdominal aortic aneurysms.

Editor's Choice -- European Society for Vascular Surgery (ESVS) 2024 Clinical Practice Guidelines on the Management of Abdominal Aorto-Iliac Artery Aneurysms

OBJECTIVE

The European Society for Vascular Surgery (ESVS) has developed clinical practice guidelines for the care of patients with aneurysms of the abdominal aorta and iliac arteries in succession to the 2011 and 2019 versions, with the aim of assisting physicians and patients in selecting the best management strategy.

METHODS

The guideline is based on scientific evidence completed with expert opinion on the matter. By summarising and evaluating the best available evidence, recommendations for the evaluation and treatment of patients have been formulated. The recommendations are graded according to a modified European Society of Cardiology grading system, where the strength (class) of each recommendation is graded from I to III and the letters A to C mark the level of evidence.

RESULTS

A total of 160 recommendations have been issued on the following topics: Service standards, including surgical volume and training; Epidemiology, diagnosis, and screening; Management of patients with small abdominal aortic aneurysm (AAA), including surveillance, cardiovascular risk reduction, and indication for repair; Elective AAA repair, including operative risk assessment, open and endovascular repair, and early complications; Ruptured and symptomatic AAA, including peri-operative management, such as permissive hypotension and use of aortic occlusion balloon, open and endovascular repair, and early complications, such as abdominal compartment syndrome and colonic ischaemia; Long term outcome and follow up after AAA repair, including graft infection, endoleaks and follow up routines; Management of complex AAA, including open and endovascular repair; Management of iliac artery aneurysm, including indication for repair and open and endovascular repair; and Miscellaneous aortic problems, including mycotic, inflammatory, and saccular aortic aneurysm. In addition, Shared decision making is being addressed, with supporting information for patients, and Unresolved issues are discussed.

CONCLUSION

The ESVS Clinical Practice Guidelines provide the most comprehensive, up to date, and unbiased advice to clinicians and patients on the management of abdominal aorto-iliac artery aneurysms.

Vascular Quality Initiative assessment of compliance with Society for Vascular Surgery clinical practice guidelines on the management of extracranial cerebrovascular disease

OBJECTIVES

Compliance with Society for Vascular Surgery (SVS) clinical practice guidelines (CPGs) is associated with improved outcomes for the treatment of abdominal aortic aneurysm, but this has not been assessed for carotid artery disease. The Vascular Quality Initiative (VQI) registry was used to examine compliance with the SVS CPGs for the management of extracranial cerebrovascular disease and its impact on outcomes.

METHODS

The 2021 SVS extracranial cerebrovascular disease CPGs were reviewed for evaluation by VQI data. Compliance rates by the center and provider were calculated, and the impact of compliance on outcomes was assessed using logistic regression with inverse probability-weighted risk adjustment for each CPG recommendation, allowing for clustering by the center. Our primary outcome was a composite end point of in-hospital stroke/death. As a secondary analysis, compliance with the 2021 SVS carotid implementation document recommendations and associated outcomes were also assessed.

RESULTS

Of the 11 carotid CPG recommendations, 4 (36%) could be evaluated using VQI registry data. Median center-specific CPG compliance ranged from 38% to 95%, and median provider-specific compliance ranged from 36% to 100%. After adjustment, compliance with 2 of the recommendations was associated with lower rates of in-hospital stroke/death: first, the use of best medical therapy (antiplatelet and statin therapy) in low/standard surgical risk patients undergoing carotid endarterectomy for >70% asymptomatic stenosis (event rate in compliant vs noncompliant cases 0.59% vs 1.3%; adjusted odds ratio: 0.44, 95% confidence interval: 0.29-0.66); and second, carotid endarterectomy over transfemoral carotid artery stenting in low/standard surgical risk patients with >50% symptomatic stenosis (1.9% vs 3.4%; adjusted odds ratio: 0.55, 95% confidence interval: 0.43-0.71). Of the 132 implementation document recommendations, only 10 (7.6%) could be assessed using VQI data, with median center- and provider-specific compliance rates ranging from 67% to 100%. The impact of compliance on outcomes could only be assessed for 6 (4.5%) of these recommendations, and compliance with all 6 recommendations was associated with lower stroke/death.

CONCLUSIONS

Few SVS recommendations could be assessed in the VQI because of incongruity between the recommendations and the VQI data variables collected. Although guideline compliance was extremely variable among VQI centers and providers, compliance with most of these recommendations was associated with improved outcomes after carotid revascularization. This finding confirms the value of guideline compliance, which should be encouraged for centers and providers. Optimization of VQI data to promote evaluation of guideline compliance and distribution of these findings to VQI centers and providers will help facilitate quality improvement efforts in the care of vascular patients.

Elevated triglyceride-glucose index predicts mortality following endovascular abdominal aortic aneurysm repair

Background

Triglyceride-glucose (TyG) index has been increasingly studied as a simple and reliable predictor of adverse events of some cardiovascular disorders. However, its prognostic effect on postoperative outcomes in patients with abdominal aortic aneurysm (AAA) is still unknown. The current study aimed to explore the potential role of TyG index in predicting mortality of AAA patients following endovascular aneurysm repair (EVAR).

Materials and methods

This retrospective cohort study analyzed the preoperative TyG index in a total of 188 AAA patients who underwent EVAR with the follow-up of 5 years. Data were analyzed with SPSS software Version 23.0. Association between the TyG index and all-cause mortality was evaluated using Cox regression models and Kaplan-Meier method.

Results

Cox regression analyses showed that per 1-unit increment of TyG index was significantly associated with an increased risk of postoperative 30-day, 1-year, 3-year, and 5-year mortality, even after adjustment for potential confounders (all P<0.05). Kaplan-Meier analysis suggested that patients with high TyG index (≥8.68) had a worse overall survival (P = 0.007).

Conclusion

The elevated TyG index could be a promising predictive factor of postoperative mortality in AAA patients after EVAR.

The Contemporary Impact of Body Mass Index on Open Aortic Aneurysm Repair

INTRODUCTION

The Centers for Disease Control and Prevention (CDC) has deemed obesity a national epidemic and contributor to other leading causes of death including heart disease, stroke, and diabetes. Accordingly, the role of body mass index (BMI) and its impact on surgical outcomes has been a focus of persistent investigation. The purpose of this study was to quantify the effect of BMI on open abdominal aortic aneurysm repair (oAAA) outcomes in contemporary practice.

METHODS

All elective oAAAs in the VQI (2010-2021) were identified. End-points included 30-day death, in-hospital complications and 1-year mortality. Patients were stratified into four BMI cohorts (BMI<18.5, 18.5≤BMI<25, 25≤BMI<30, BMI≥30). Spline interpolation was used to explore a potential non-linear association between BMI and perioperative mortality. Mixed-effects Cox regression was used to assess the association between BMI and 1-year survival.

RESULTS

9,479 patients underwent oAAA over the study interval (median age-70, 74%-male, BMI 27±6). Lower BMI patients(<18.5) compared to higher BMI(>30) patients were more likely to be women (53% vs. 32%;p<.0001), current smokers(65% vs. 50%;p<.0001), and have COPD(58% vs. 37%;p<.0001). In contrast, an increased BMI was associated with a greater prevalence of diabetes and CAD (DM-26% vs. 6%;p<.0001; CAD-27% vs. 20%;p=.01). There was no difference in cross-clamp position or visceral/renal bypass between groups, though low BMI patients necessitated more frequent infrainguinal bypass(5% vs. 2%;p=.0002). 30-day mortality and in-hospital complications were greater among low BMI patients(30-day mortality:12% vs. 4%;p<.0001;complications-47% vs. 37%;p<.0001). Interestingly, low BMI conferred a nearly 2-fold increase in observed pulmonary complications(18% vs. 11%;p<.0001). Surgical site infections were twice as common among the lowest and highest BMI groups(4% vs. 2%;p<.0001). 1-year mortality was greatest among low BMI patients(23% vs. 9%;p<.0001). Adjusted spline-fit analysis demonstrated increased mortality among patients with BMI<21 or >34(BMI<18.5-HR 2.1, 95%CI 1.6-2.8;p<.0001; BMI>34-HR 1.3, 95%CI 1.1-1.6;p=.009).

CONCLUSION

Both low (<18.5) and high (>34) BMI were associated with increased oAAA mortality in current practice. Despite the perception that obesity confers substantial surgical risk during oAAA, diminished BMI was associated with a 3-fold increase in 30-day and 1-year mortality. It appears that BMI extremes are distinct proxies for differential clinical phenotypes and should inform risk stratification for oAAA repair.

Capturing the Complexity of Open Abdominal Aortic Surgery in the Endovascular Era

OBJECTIVE

Volume and quality benchmarks for open abdominal aortic surgery and particularly open aortic aneurysm repair (OAR) in the endovascular era are guided by the Society for Vascular Surgery (SVS) guidelines, but the Vascular Quality Initiative (VQI) OAR module fails to capture the full spectrum of complex OAR. We hypothesized that VQI-ineligible complex OAR is the dominant form of open repairs performed at a VQI-participating tertiary center.

METHODS

All OAR cases performed at a single tertiary care center from 2007 to 2020 were reviewed. The VQI OAR criteria were applied with exclusions (non-VQI) defined as concomitant renal bypass, clamping above the superior mesenteric artery (SMA) or celiac artery, repairs performed for trauma, anastomotic aneurysm, isolated iliac aneurysm, or infected aneurysms. Linear regression was used to assess temporal trends.

RESULTS

Among a total of 481 open abdominal aortic operations, 355 (74%) were OAR. The average annual OAR volume remained stable over 14 years (25 ± 6; P = .46). Non-VQI OAR comprised 54% of all cases and persisted over time (R² = .047, P = .46). Supra-celiac clamping (35%) was often necessary. The proportion of endograft explantation cases significantly increased over time from 4% in 2007 to 20% in 2019 (P = .01). Infectious indications represented 20% (n = 70) of cases. Visceral branch grafts were performed in 16% of all cases. OAR for ruptured aneurysm constituted 10% of cases. Thirty-day mortality was significantly higher in non-VQI vs. VQI-eligible OAR cases (10% vs. 4%; P = .04).

CONCLUSIONS

Complex OAR comprises a majority of OAR cases in a contemporary tertiary referral hospital, yet these cases are not accounted for in the VQI. Creation of a "complex OAR" VQI module would capture these cases in a quality-driven national registry and help to better inform benchmarks for volume and outcomes in aortic surgery.

Thresholds for abdominal aortic aneurysm repair in Canada and United States

BACKGROUND

Previous studies have demonstrated significant geographic variations in the management of abdominal aortic aneurysms (AAA) despite standard guidelines. Differences in patient selection, operative technique, and outcomes for AAA repair in Canada versus United States were assessed.

METHODS

The Vascular Quality Initiative was used to identify all patients who underwent elective endovascular or open AAA repair between 2010 and 2019 in Canada and the United States. Demographic, clinical, and procedural characteristics were recorded and differences between countries were assessed using independent t test and χ² test. The primary outcome was the percentage of AAA repaired below recommended diameter thresholds (men, <5.5 cm; women, <5.0 cm). The secondary outcomes were in-hospital and 1-year mortality rates. Associations between region and outcomes were assessed using univariate/multivariate logistic regression and Cox proportional hazards analysis.

RESULTS

There were 51,455 US patients and 1451 Canadian patients who underwent AAA repair in Vascular Quality Initiative sites during the study period. There was a higher proportion of endovascular repairs in the United States (83.7% vs 68.4%; odds ratio [OR], 2.38; 95% confidence interval [CI], 2.13-2.63; P < .001). US patients had more comorbidities, including hypertension, congestive heart failure, chronic kidney disease, and prior revascularization. The percentage of AAA repaired below recommended thresholds was significantly higher in the United States (38.8% vs 15.2%; OR, 3.57; 95% CI, 3.03-4.17; P < .001). This difference persisted after controlling for demographic, clinical, and procedural characteristics (adjusted OR, 3.57; 95% CI, 2.63-4.17; P < .001). Factors that predicted AAA repair below recommended thresholds were US region (adjusted OR, 3.57; 95% CI, 3.03-4.17), male sex (adjusted OR, 2.89; 95% CI, 2.72-3.07), and endovascular repair (adjusted OR, 2.08; 95% CI, 1.95-2.21). The in-hospital mortality rate was low (1.0% vs 0.8%) and the 1-year rate mortality was similar between countries (hazard ratio, 0.96; 95% CI, 0.70-1.31; P = .79).

CONCLUSIONS

There are significant variations in AAA management between Canada and the United States. A greater proportion of US patients underwent AAA repair below the recommended diameter thresholds. This finding is partly driven by a higher percentage of endovascular repairs. Despite these differences, the perioperative and 1-year mortality rates are similar. Future studies should investigate reasons for these variations and quality improvement projects are needed to standardize care.

Non-guideline-compliant endovascular abdominal aortic aneurysm repair in women is associated with increased mortality and reintervention compared with men

OBJECTIVE

Sex-based disparities in surgical outcomes have emerged as an important focus in contemporary healthcare delivery. Likewise, the appropriate usage of endovascular abdominal aortic aneurysm repair (EVAR) in the United States remains a subject of ongoing controversy, with a significant number of U.S. EVARs failing to adhere to the Society for Vascular Surgery (SVS) clinical practice guideline (CPG) diameter thresholds. The purpose of the present study was to determine the effect of sex among patients undergoing EVAR that was not compliant with the SVS CPGs.

METHODS

All elective EVAR procedures for abdominal aortic aneurysms without a concomitant iliac aneurysm (≥3.0 cm) in the SVS Vascular Quality Initiative were analyzed (2015-2019; n = 25,112). SVS CPG noncompliant repairs were defined as a size of <5.5 cm for men and <5.0 cm for women. The primary endpoint was 30-day mortality. The secondary endpoints were all-cause mortality, complications, and reintervention. Logistic regression was performed to control for surgeon- and patient-level factors. Freedom from the endpoints was determined using the Kaplan-Meier method.

RESULTS

Noncompliant EVAR was performed in 9675 patients (38.5%). Although men were significantly more likely to undergo such procedures (90% vs 10%; odds ratio [OR], 3.1; 95% confidence interval [CI], 2.9-3.4; P < .0001), the 30-day mortality was greater for the women than the men (1.8% vs 0.5%; P = .0003). Women also experienced significantly higher rates of multiple complications, including postoperative myocardial infarction (1% vs 0.3%; P = .006), respiratory failure (1.4% vs 0.6%; P = .01), intestinal ischemia (0.7% vs 0.2%; P = .003), access vessel hematoma (3% vs 1.2%; P = .0006), and iliac access vessel injury (2.4% vs 0.8%; P < .0001). Additionally, women experienced increased overall 1-year reintervention rates (11.5% vs 5.8%; P < .0001). In the adjusted analysis, 30-day mortality and any in-hospital complication risk remained significantly greater for the women (30-day death: OR, 3.1; 95% CI, 1.6-5.8; P = .0005; in-hospital complication: OR, 1.9; 95% CI, 1.4-2.6; P < .0001). Women also experienced increased reintervention rates over time compared with men (OR, 1.5; 95% CI, 1.1-2.2; P = .02).

CONCLUSIONS

Although men were more likely to undergo non-CPG compliant EVAR, women experienced increased short-term morbidity and 30-day mortality and higher rates of reintervention when undergoing non-CPG compliant EVAR. These unanticipated findings necessitate increased scrutiny of current U.S. sex-based EVAR practice and should caution against the use of non-CPG compliant EVAR for women.

Regional Market Competition is Associated with Aneurysm Diameter at the Time of EVAR

BACKGROUND

Local market competition has been previously associated with more aggressive surgical decision-making. For example, more local competition for organs is associated with acceptance of lower quality kidney offers in transplant surgery. We hypothesized that market competition would be associated with the size of an abdominal aortic aneurysm (AAA) at the time of elective endovascular aneurysm repair (EVAR).

METHODS

We included all elective EVARs reported in the Vascular Quality Initiative database (2012-2018). Small AAAs were defined as a maximum diameter <5.5 cm in men or <5.0 cm in women. We calculated the Herfindahl-Hirschman Index (HHI), a measure of physician market concentration (higher HHI = less market competition), for each US census region. Multilevel regression was used to examine the association between the size of AAA at EVAR and HHI, clustering by region.

RESULTS

Of 37,914 EVARs performed, 15,379 (40.6%) were for small AAAs. There was significant variation in proportion of EVARs performed for small AAAs across regions (P < 0.001). The South had both the highest proportion of EVARs for small AAAs (44.2%) as well as the highest market competition (HHI 50), whereas the West had the lowest proportion of EVARs for small AAAs (35.0%) and the lowest market competition (HHI 107). Adjusting for patient characteristics, each 10 unit increase in HHI was associated with a 0.1 mm larger maximum AAA diameter at the time of EVAR (95% CI 0.04-0.24 mm, P = 0.005).

CONCLUSIONS

Physician market concentration is independently associated with AAA diameter at time of elective EVAR. These data suggest that physician decision-making for EVAR is impacted by market competition.