Comparison of first- and second-generation prostheses for endoluminal repair of abdominal aortic aneurysms: A 6-year study with life table analysis

Purpose: The outcome of endoluminal repair of abdominal aortic aneurysms wi th two generations of prostheses was analyzed and compared. Methods: Between May 1992 and December 1998, 266 patients underwent electiv e endoluminal repair of an AAA. First-generation prostheses were used in 11 8 patients (group I), and second-generation prostheses were used in 148 pat ients (group II). The two groups were similar in age, sex, and size of AAA. The proportion of patients with comorbidities was higher in group I than i n group II, bur not significantly. First-generation devices were characteri zed by large (24F internal diameter) delivery systems, one-piece constructi on, and a lack of metallic support throughout their length. Second-generati on devices had smaller (21F or smaller internal diameter) delivery systems, modular construction, and a metallic frame throughout the length of the pr ostheses. The major endpoint criteria were survival and successful endolumi nal repair. Success was defined as the exclusion of the aneurysm sac from t he circulation, with stability or the reduction in AAA maximum transverse d iameter. Persistent endoleaks were classified as failures, irrespective of whether they were subsequently corrected by means of secondary endovascular intervention. The minimum follow-up period was 5 months for each of the 26 6 patients. Analysis was performed by means of the Life-table method. Results: Perioperative mortality was not significantly different between gr oup I (4.2%) and group II (2.7%). There was a statistically significant dif ference between the survival curves of the two generations, which favored g roup II (P = .012). There was a significant (P < .001) difference between t he two generations of patients in their conditional probability of graft fa ilure when the competing risk of all-cause mortality was considered. Second -generation patients were at a lower risk of graft failure than first-gener ation patients. The probability of failure, expressed as a proportion of gr afts failing at 2 years, was 0.15 for patients with second-generation prost heses and 0.33 for patients with first-generation prostheses. Conclusion: Endoluminal AAA repair is a safe procedure, whether first- or s econd-generation prostheses are used. Survival and probability of graft suc cess were significantly higher with second-generation prostheses than with first-generation prostheses. This improvement in outcome resulted from a co mbination of increasing clinical experience and advances in technology. A m ore accurate evaluation of the role of the endoluminal method in AAA repair would be achieved by studying patients in whom second-generation devices w ere used, rather than longer term studies in which first- and second-genera tion devices were used.