External validation of a 5-year survival prediction model after elective abdominal aortic aneurysm repair

Abstract

Objective The benefit of prophylactic repair of abdominal aortic aneurysms (AAAs) is based on the risk of rupture exceeding the risk of death from other comorbidities. The purpose of this study was to validate a 5-year survival prediction model for patients undergoing elective repair of asymptomatic AAA <6.5 cm to assist in optimal selection of patients. Methods All patients undergoing elective repair for asymptomatic AAA <6.5 cm (open or endovascular) from 2002 to 2011 were identified from a single institutional database (validation group). We assessed the ability of a prior published Vascular Study Group of New England (VSGNE) model (derivation group) to predict survival in our cohort. The model was assessed for discrimination (concordance index), calibration (calibration slope and calibration in the large), and goodness of fit (score test). Results The VSGNE derivation group consisted of 2367 patients (70% endovascular). Major factors associated with survival in the derivation group were age, coronary disease, chronic obstructive pulmonary disease, renal function, and antiplatelet and statin medication use. Our validation group consisted of 1038 patients (59% endovascular). The validation group was slightly older (74 vs 72 years; P < .01) and had a higher proportion of men (76% vs 68%; P < .01). In addition, the derivation group had higher rates of advanced cardiac disease, chronic obstructive pulmonary disease, and baseline creatinine concentration (1.2 vs 1.1 mg/dL; P < .01). Despite slight differences in preoperative patient factors, 5-year survival was similar between validation and derivation groups (75% vs 77%; P = .33). The concordance index of the validation group was identical between derivation and validation groups at 0.659 (95% confidence interval, 0.63–0.69). Our validation calibration in the large value was 1.02 (P = .62, closer to 1 indicating better calibration), calibration slope of 0.84 (95% confidence interval, 0.71–0.97), and score test of P = .57 (>.05 indicating goodness of fit). Conclusions Across different populations of patients, assessment of age and level of cardiac, pulmonary, and renal disease can accurately predict 5-year survival in patients with AAA <6.5 cm undergoing repair. This risk prediction model is a valid method to assess mortality risk in determining potential overall survival benefit from elective AAA repair.

Outcomes of Type II Endoleak Treatment Using Ethylene Vinyl Alcohol Copolymer (OnyxTM)

“…[36][37][38][39] The 5-year survival after EVAR ranges from 57%-75%. [40][41][42][43][44] Previous studies have shown that the majority of deaths after EVAR are due to non-surgical causes such as cardiovascular disease and cancer. 40 Because of these factors, it is difficult to accurately compare long term outcomes among study groups.…”

Correlation between Sex and Prognosis of Acute Aortic Dissection in the Chinese Population

“…Some trials have found statin therapy to be independently associated with better long-term survival of aortic aneurysms. [ 22 23 24 ] Possibly owing to reasons as follows: The pleiotropic effects of statins, which influence endothelial function, inflammatory response, thrombus formation, and plaque stability, could affect postoperative and long-term outcomes. [ 25 26 ] The other effect is thought to be related to downregulation of metalloproteinases.…”

Development and Validation of a Predictive Model to Aid in the Management of Intact Abdominal Aortic Aneurysms

“…The reported calibration slope of the model was 0.84 and the cstatistic was 0.66. 35 All these long-term prediction models have inherited limitations and require further validation and testing in clinical decision making. A summary of the available AAA decision aids is shown in Table 3.…”