Predictors of survival following open and endovascular repair of abdominal aortic aneurysms

Abstract

Clinical decision making for asymptomatic abdominal aortic aneurysms (AAAs) weighs risk of aneurysm rupture, treatment hazards, and overall survival expectations. AAA diameter is the primary parameter in assessing rupture risk. Perioperative risk assessment has been extensively studied, and in-hospital mortality has been reduced to less than 8% with higher-risk open repair and less than 3% with endovascular repair. The purpose of this report is to determine risk factors that predict 2-year survival following open and endovascular AAA repair. We studied 334 patients enrolled in a multicenter clinical trial evaluating an endovascular graft in comparison to standard open repair of infrarenal AAA. Demographic, medical history, physical examination, laboratory, anatomic, procedural, and standardized risk score system variables were analyzed in a multivariable Cox proportional hazard model. Overall survival was 89% at 2 years. Heart disease, cancer, and stroke were the most common causes of death, and no deaths were due to AAA rupture. Cox modeling demonstrated that there were several independent predictors for death after AAA repair: smaller body mass index (p=0.005), Society for Vascular Surgery pulmonary risk score >or=1 (p=0.005), history of erectile dysfunction (p=0.008), history of heart valve replacement (p=0.008), lower preoperative platelet count (p=0.012), larger ratio of AAA diameter/proximal neck diameter (p=0.020), and lower ankle-brachial index (p=0.031). Age, gender, and open or endovascular treatment group are not significant independent risk factors for 2-year mortality in this study. Clinical, laboratory, and anatomic factors predict survival after open and endovascular repair of AAAs. With progressive reduction of in-hospital mortality, assessment of patient longevity after AAA repair has become a more important factor in clinical decision making. Use of valid predictors of patient survival will optimize resource utilization and improve overall patient outcomes. Better selection of patients for any method of repair may improve overall utility more than choice of open or endovascular techniques.