Modern mortality risk stratification scores accurately and equally predict real-world postoperative mortality after ruptured abdominal aortic aneurysm

Objective: It is often unclear which patients presenting with a ruptured abdominal aortic aneurysm (rAAA) are likely to survive after surgery. The Harborview Medical Center (HMC), Dutch Aneurysm Score (DAS), and Vascular Study Group of New England (VSGNE) risk scores have been recent attempts at predicting mortality in this setting. We compared the prognostic value of these scoring systems for patients at our institution with rAAA.

Methods: A retrospective chart review was performed for all patients who received surgery at our institution for rAAA between January 1, 2011, and November 27, 2019. The χ², Fisher's exact, and t-tests were used to screen preoperative variables against in-hospital mortality. HMC, DAS, and VSGNE scores were calculated for each patient and tested against in-hospital mortality. Logistic regression and receiver operating characteristic curves were used to assess performance of each scoring system.

Results: Sixty-four patients were identified during the study period. Fifteen patients were excluded because 4 patients chose comfort care and an additional 11 patients were missing key variables. The final cohort for analysis included 49 patients who underwent surgery, including 33 patients receiving endovascular repair and 16 patients receiving open repair. The in-hospital mortality was 37% (24% for endovascular repair vs 63% for open repair). Individual variables associated with in-hospital mortality were lowest preoperative systolic blood pressure (P = .036), creatinine greater than 2.0 mg/dL (P = .020), first recorded intraoperative pH (P = .007), and use of suprarenal aortic control (P = .025), and preoperative cardiac arrest approached significance (P = .051). Plots of the HMC and VSGNE scores vs in-hospital mortality rate produced linear relationships (R² = 0.97 and R² = 0.93, respectively), in which a higher score was associated with a greater likelihood of mortality. On logistic regression analysis using HMC score components, creatinine greater than 2.0 mg/dL produced a significant association with in-hospital mortality (odds ratio, 12.3; 95% confidence interval [CI], 1.1-131.7). Similar analysis using VSGNE components produced a significant association between suprarenal aortic control and in-hospital mortality (odds ratio, 5.5; 95% CI, 1.2-25.5). receiver operating characteristic curves produced an area under the curve of 0.74 (95% CI, 0.60-0.88), 0.73 (95% CI, 0.58-0.87), and 0.67 (95% CI, 0.51-0.83) for the HMC, VSGNE, and DAS, respectively.

Conclusions: The HMC, VSGNE, and DAS scores performed similarly and adequately predicted in-hospital mortality after rAAA. The HMC score holds the added benefit of using preoperative variables, setting it apart as a valid prognostic indicator in the preoperative setting.