Pre-op variable calculator accurately predicts AAA survival

(HealthDay)—An independent calculator that uses preoperative variables can accurately predict long-term survival in abdominal aortic aneurysm repair, according to a study published in the June issue of Anaesthesia.

John B. Carlisle, M.B.Ch.B., from Torbay Hospital in Torquay, U.K., and colleagues observed survival after scheduled repair of abdominal aortic aneurysm in 1,096 patients, of whom 943 had complete data. Discrimination and calibration were compared for an external model and the Kaplan-Meier model generated from study data. The survival calculator was developed based on the year of surgery, age, and sex, and included other preoperative variables.

Survival was observed for a median of 3.0 years, and 250 patients died. The researchers found that at one to five postoperative years, Harrel's concordance index was 0.73, 0.71, 0.68, 0.67, and 0.66, respectively. Compared with the 114 patients with 70 percent predicted mortality, patients with median five-year predicted mortality of 40, 18, and 8 percent had significantly lower observed mortality (hazard ratios, 0.58, 0.30, and 0.19, respectively). Survival was similar for the prediction by the external calculator and Kaplan-Meier estimate.

"In conclusion, we believe that the calculator performed sufficiently well to inform patients considering whether to proceed to scheduled repair of abdominal aortic aneurysms or to enter the ultrasound screening program," the authors write.