A Risk Score Model to Characterize Predictors of Survival After Elective Endovascular Abdominal Aortic Aneurysm Repair

Abstract

The purpose of this study was to identify significant predictors of mortality after elective abdominal aortic aneurysm repair. We included all elective endovascular aneurysm repairs from 16 centers across the “Virginia's group” of the Society for Vascular Surgery Patient Safety Organization. Patients were classified into normal (estimated glomerular filtration rate [eGFR] ≥60 mL/min/1.73 m2), moderate chronic renal insufficiency (eGFR 30-59), or severe chronic renal insufficiency (eGFR <30). Kaplan-Meier and Cox regression were used to measure and to determine the predictors of mortality. A score equation was developed to categorize patients into low, medium, and high mortality risk. A total of 5678 endovascular aneurysm repair patients were included with an age of 73.6 ± 8.2 years. The majority were male (81.6%) with a history of smoking (86.1%). There were three deaths within 30 days (0.1%). Overall survival was 81.2% and 69.2% at 5 and 8 years, respectively. Several factors were associated with poor survival: unstable angina (hazard ratio [HR], 2.8; P = .008), on dialysis (HR, 3.7; P < .001), eGFR 80 (HR, 3.2; P < .001), age 75 to 79 years (HR, 2.2; P < .001), chronic obstructive pulmonary disease on oxygen (HR, 3.3; P5.8 cm (HR, 1.2; P = .043), and high risk for surgery (HR, 1.4; P = .043). Preoperative aspirin use and body mass index of 25 to 35 were both found to be protective (HR, 0.78 [P = .017] and HR, 0.8 [P = .024], respectively. The 5- and 8-year survival rates for patients with low, medium, and high risk were 89.2%, 79.7%, and 80.7% and 68.9%, 64.1%, and 47.5%, respectively (P < .001). Survival for patients with high-risk score was 47.5% at 8 years. This risk score model offers an objective tool to better guide recommendations for interventions in this era of cost-effectiveness.