Early Postoperative Mortality Among US Veterans With a Robust Physiologic Reserve Undergoing Open or Endovascular Abdominal Aortic Aneurysm Repair

The association between frailty and outcomes following ruptured abdominal aortic aneurysm repair

OBJECTIVE

Endovascular aortic repair (EVAR) is a less invasive method than the more physiologically stressful open surgical repair (OSR) for patients with anatomically appropriate abdominal aortic aneurysms (AAAs). Early postoperative outcomes are associated with both patients; physiologic reserve and the physiologic stresses of the surgical intervention. Among frail patients with reduced physiologic reserve, the stress of an aortic rupture in combination with the stress of an operative repair are less well tolerated, raising the risk of complications and mortality. This study aims to evaluate the difference in association between frailty and outcomes among patients undergoing minimally invasive EVAR and the physiologically more stressful OSR for ruptured AAAs (rAAAs).

METHODS

Our retrospective cohort study included adults undergoing rAAA repair in the Vascular Quality Initiative from 2010 to 2022. The validated Risk Analysis Index (RAI) (robust, ≤20; normal, 21-29; frail, 30-39; very frail, ≥40) quantified frailty. The association between the primary outcome of 1-year mortality and frailty status as well as repair type were compared using multivariable Cox models generating adjusted hazard ratios (aHRs) with 95% confidence intervals (CIs). Interaction terms evaluated the association's moderation.

RESULTS

We identified 5806 patients (age, 72 ± 9 years; 77% male; EVAR, 65%; robust, 6%; normal, 48%; frail, 36%; very, frail 10%) with a 53% observed 1-year mortality rate following rAAA repair. OSR (aHR, 1.43; 95% CI, 1.19-1.73) was associated with increased 1-year mortality when compared with EVAR. Increasing frailty status (frail aHR, 1.26; 95% CI, 1.00-1.59; very frail aHR, 1.64; 95% CI, 1.26-2.13) was associated with increased 1-year mortality, which was moderated by repair type (P-interaction < .05). OSR was associated with increased 1-year mortality in normal (aHR, 1.49; 95% CI, 1.20-1.87) and frail (aHR, 1.51; 95% CI, 1.20-1.89), but not among robust (aHR, 0.88; 95% CI, 0.59-1.32) and very frail (aHR, 1.29; 95% CI, 0.97-1.72) patients.

CONCLUSIONS

Frailty and OSR were associated with increased adjusted risk of 1-year mortality following rAAA repair. Among normal and frail patients, OSR was associated with an increased adjusted risk of 1-year mortality when compared with EVAR. However, there was no difference between OSR and EVAR among robust patients who can well tolerate the stress of OSR and among very frail patients who are unable to withstand the surgical stress from rAAA regardless of repair type.

Conflicting European and North American Society Abdominal Aortic Aneurysm (AAA) Volume Guidelines Differentially Discriminate Peri-operative Mortality After Elective Open AAA Repair

OBJECTIVE

The European Society for Vascular Surgery (ESVS) guidelines endorse a minimum abdominal aortic aneurysm (AAA) repair volume of 20 open (OAR) and or endovascular (EVAR) AAA repair procedures per year as a proxy for high quality care. In contrast, the Society for Vascular Surgery (SVS) espouses 10 exclusively OARs per year. Given the differences in these volume standards and definitions, debate persists regarding surgeon credentialing and healthcare resource allocation. This analysis aimed to determine which society endorsed volume benchmark better discriminates OAR mortality.

METHODS

A retrospective national registry based cohort analysis. Patients undergoing elective OAR were compared between centres meeting either ESVS (≥ 20 AAA procedures/year) or SVS (≥ 10 OARs/year) volume thresholds within the Vascular Quality Initiative (2010 - 2020). The primary outcome was in hospital death. Logistic regression was used for risk adjusted comparisons.

RESULTS

A total of 8 761 OARs were performed at 193 US centres, and the median (IQR) volume was 6.6 (3.3, 9.9) OARs/year. When applying the SVS centre volume definition, the proportion of centres meeting ESVS and SVS minimum case thresholds was 12% (n = 22) and 25% (n = 48), respectively. The absolute mortality difference was 0.3% between centres performing ≥ 20 vs. ≥ 10 OARs/year (2.6% vs. 2.9%; p = .51). There was an incremental association between OAR volume and crude mortality rate; however, this absolute difference between lower and higher thresholds was only 0.2%/procedure (OR 0.98, 95% CI 0.97 - 0.99; p < .001). Moreover, no difference in risk adjusted mortality was detected between volume standards (≥ 10 vs. ≥ 20; p = .78). In sub-analysis, the ESVS ≥ 20 total composite AAA repair volume threshold was not associated with mortality (p = .17); however, increasing the proportion of OAR cases making up the total annual AAA centre volume inversely correlated with mortality (p = .008).

CONCLUSION

It appears that the SVS endorsed AAA centre volume threshold using exclusively OAR had a modest ability to discriminate peri-operative mortality outcomes and was superior to the current composite ESVS volume guideline in differentiating centre performance. These findings raise questions regarding the clinical validity of using EVAR as a volume proxy for OAR.

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.