Is In Hospital Mortality Following EVAR Still a Valid Outcome Measure?

Earned outcomes correlate with reliability-adjusted surgical mortality after abdominal aortic aneurysm repair and predict future performance

OBJECTIVE

Cumulative, probability-based metrics are regularly used to measure quality in professional sports, but these methods have not been applied to health care delivery. These techniques have the potential to be particularly useful in describing surgical quality, where case volume is variable and outcomes tend to be dominated by statistical "noise." The established statistical technique used to adjust for differences in case volume is reliability-adjustment, which emphasizes statistical "signal" but has several limitations. We sought to validate a novel measure of surgical quality based on earned outcomes methods (deaths above average [DAA]) against reliability-adjusted mortality rates, using abdominal aortic aneurysm (AAA) repair outcomes to illustrate the measure's performance.

METHODS

Earned outcomes methods were used to calculate the outcome of interest for each patient: DAA. Hospital-level DAA was calculated for non-ruptured open AAA repair and endovascular aortic repair (EVAR) in the Vascular Quality Initiative database from 2016 to 2019. DAA for each center is the sum of observed - predicted risk of death for each patient; predicted risk of death was calculated using established multivariable logistic regression modeling. Correlations of DAA with reliability-adjusted mortality rates and procedure volume were determined. Because an accurate quality metric should correlate with future results, outcomes from 2016 to 2017 were used to categorize hospital quality based on: (1) risk-adjusted mortality; (2) risk- and reliability-adjusted mortality; and (3) DAA. The best performing quality metric was determined by comparing the ability of these categories to predict 2018 to 2019 risk-adjusted outcomes.

RESULTS

During the study period, 3734 patients underwent open repair (106 hospitals), and 20,680 patients underwent EVAR (183 hospitals). DAA was closely correlated with reliability-adjusted mortality rates for open repair (r = 0.94; P < .001) and EVAR (r = 0.99; P < .001). DAA also correlated with hospital case volume for open repair (r = -.54; P < .001), but not EVAR (r = 0.07; P = .3). In 2016 to 2017, most hospitals had 0% mortality (55% open repair, 57% EVAR), making it impossible to evaluate these hospitals using traditional risk-adjusted mortality rates alone. Further, zero mortality hospitals in 2016 to 2017 did not demonstrate improved outcomes in 2018 to 2019 for open repair (3.8% vs 4.6%; P = .5) or EVAR (0.8% vs 1.0%; P = .2) compared with all other hospitals. In contrast to traditional risk-adjustment, 2016 to 2017 DAA evenly divided centers into quality quartiles that predicted 2018 to 2019 performance with increased mortality rate associated with each decrement in quality quartile (Q1, 3.2%; Q2, 4.0%; Q3, 5.1%; Q4, 6.0%). There was a significantly higher risk of mortality at worst quartile open repair hospitals compared with best quartile hospitals (odds ratio, 2.01; 95% confidence interval, 1.07-3.76; P = .03). Using 2016 to 2019 DAA to define quality, highest quality quartile open repair hospitals had lower median DAA compared with lowest quality quartile hospitals (-1.18 DAA vs +1.32 DAA; P < .001), correlating with lower median reliability-adjusted mortality rates (3.6% vs 5.1%; P < .001).

CONCLUSIONS

Adjustment for differences in hospital volume is essential when measuring hospital-level outcomes. Earned outcomes accurately categorize hospital quality and correlate with reliability-adjustment but are easier to calculate and interpret. From 2016 to 2019, highest quality open AAA repair hospitals prevented >40 perioperative deaths compared with the average hospital, and >80 perioperative deaths compared with lowest quality hospitals.

Bilateral Use of Iliac Branch Devices for Aortoiliac Aneurysms Is Safe and Feasible, and Procedural Volume Does Not Seem to Affect Technical or Clinical Effectiveness: Early and Midterm Results From the pELVIS International Multicentric Registry

OBJECTIVE

To evaluate early and follow-up outcomes following bilateral use of iliac branch devices (IBD) for aortoiliac endografting and assess the impact of center volume. We used data from the pELVIS international multicentric registry.

METHODS

For the purpose of this study, only those patients receiving concomitant bilateral IBD implantation were analyzed. To assess the impact that procedural volume of bilateral IBD implantation could have on early and follow-up outcomes, participating institutions were classified as Site(s) A if they had performed >10 and/or >20% concomitant bilateral IBD procedure, otherwise they were classified as Site(s) B. Endpoints of the analysis included early (ie, 30-day) mortality and morbidity, as well as all-cause and aneurysm-related mortality during follow-up. Additional endpoints that were evaluated included IBD-related reinterventions, IBD occlusion or stenosis requiring reintervention (ie, loss of primary patency), and IBD-related type I endoleak.

RESULTS

Overall, 96 patients received bilateral IBD implantation (out of 910 procedures collected in the whole pELVIS cohort), of whom 65 were treated at Site A (ie, Group A) and 31 were treated at Site(s) B (ie, Group B). In total, only 1 death occurred within 30 days from bilateral IBD implantation, and 9 patients experienced at least 1 major complication without any significant difference between subjects in Group A versus those in Group B (10.8% vs 6.5%, p=0.714). In the overall cohort, the 2-year freedom from IBD-related type I endoleaks and IBD primary patency were 96% and 92%, respectively; no significant differences were seen in those rates between Group A or Group B (95% vs 100%, p=0.335; 93% vs 88%, p=0.470). Freedom from any IBD-related reinterventions was 83% at 2 years, with similar rates between study groups (85% vs 83%, p=0.904).

CONCLUSIONS

Within the pELVIS registry, concomitant bilateral IBD implantation is a safe and feasible technique for management of aortoiliac aneurysms in patients with suitable anatomy. Despite increased technical complexity, effectiveness of the repair is satisfactory with low rates of IBD-related adverse events at mid-term follow-up. Procedural volume does not seem to affect technical or clinical outcomes after bilateral use of IBD, which remains a favorable treatment option in selected patients.

Association between Hospital Volume and Failure to Rescue after Open or Endovascular Repair of Intact Abdominal Aortic Aneurysms in the VASCUNET and International Consortium of Vascular Registries

OBJECTIVE

To investigate the association between hospital volume and failure to rescue (FtR), after open (OAR) and endovascular (EVAR) repair of intact abdominal aortic aneurysms (AAA) among centers participating in the VASCUNET and International Consortium of Vascular Registries (ICVR).

SUMMARY BACKGROUND DATA

FtR (i.e., in-hospital death following major complications) is a composite end-point representing the inability to treat complications effectively and prevent death.

METHODS

Using data from eight vascular registries, complication and mortality rates after intact AAA repair were examined (n = 60,273; EVAR-43,668; OAR-16,605). A restricted analysis using pooled data from four countries (Australia, Hungary, New Zealand, USA) reporting data on all postoperative complications (bleeding, stroke, cardiac, respiratory, renal, colonic ischemia) was performed to identify risk-adjusted association between hospital volume and FtR.

RESULTS

The most frequently reported complications were cardiac (EVAR-3.0%, OAR-8.9%) and respiratory (EVAR-1.0%, OAR-5.7%). In adjusted analysis, 4.3% of EVARs and 18.5% of OARs had at least one complication. The overall FtR rate was 10.3% after EVAR and 15.7% after OAR. Subjects treated in the highest volume centers(Q4) had 46% and 80% lower odds of FtR after EVAR (OR = 0.54; 95%CI = 0.34-0.87;p = 0.04) and OAR (OR = 0.22; 95%CI = 0.11-0.44;p < 0.001) when compared to lowest volume centers(Q1), respectively. Colonic ischemia had the highest risk of FtR for both procedures (adjusted predicted risks, EVAR: 27%, 95%CI 14%-45%; OAR: 30%, 95%CI 17%-46%).

CONCLUSIONS

In this multi-national dataset, FtR rate after intact AAA repair with EVAR and OAR is significantly associated with hospital volume. Hospitals in the top volume quartiles achieve the lowest mortality after a complication has occurred.

Editor's Choice - Variation in Intact Abdominal Aortic Aneurysm Repair Outcomes by Country: Analysis of International Consortium of Vascular Registries 2010 - 2016

OBJECTIVE

Outcomes for intact abdominal aortic aneurysm (AAA) repair vary over time and by healthcare system, country, and surgeon. The aim of this study was to analyse peri-operative mortality for intact AAA repair in 11 countries over time and compare outcomes by gender, age, and geographical location.

METHODS

Prospective data on primary repair of intact AAA were collected from 11 countries through the International Consortium of Vascular Registries (ICVR) and analysed for two time periods, 2010 - 2013 and 2014 - 2016. The primary outcome was peri-operative mortality after endovascular aneurysm repair (EVAR) and open surgical repair (OSR). Multivariable logistic regression models were used to adjust for differences in patient characteristics.

RESULTS

A total of 103 715 patients were included. The percentage of patients undergoing EVAR increased from 63.6% to 71.2% (p < .001) over the study period. This proportion varied by country from 35% in Hungary to 81% in the United States. Overall peri-operative mortality decreased from 2.1% to 1.6 % (p < .001). Mortality also declined significantly over time for both OSR 4.2% to 3.6 % (p = .002) and EVAR 1.0% to 0.7% (p = .002). Mortality was significantly higher for female than male patients (3.0% vs. 1.6% p < .001). The percentage of patients > 80 years old undergoing AAA repair remained constant at 23.6% (p = .91). Peri-operative mortality was higher for patients > 80 years than for those < 80 years old (2.7% vs. 1.6% p < .001). Forty-six per cent (n = 275) of all EVAR deaths occurred in the over 80s.

CONCLUSION

The proportion of AAA repairs performed using EVAR has increased over time. Peri-operative mortality continues to decline for both OSR and EVAR. Outcomes however were significantly worse for both women and those aged over 80, so efforts should be focused on these patient groups to further reduce elective AAA mortality rates.