Long-Term Results of Large Stent Grafts to Treat Abdominal Aortic Aneurysms

Abstract

Open surgery and endovascular treatment are currently the 2 methods of treatment for abdominal aortic aneurysms (AAAs). Although in open surgery, the proximal diameter of the implanted prostheses seldom exceeds 24mm, endovascular aneurysm repair (EVAR) makes it possible to use stent grafts up to 36mm in diameter. The aim of this study was to compare the long-term results of these large stent grafts compared with the others. A total of 908 patients operated between 1998 and 2012 for a nonruptured AAA with an infrarenal stent graft were enrolled in this multicentric retrospective study. The patients in whom the proximal diameter of the principal component of the stent graft was above 32mm belonged to group 1 (n=170) and the others belonged to group 2 (n=738). The qualitative and quantitative data were compared with the chi-squared test and the t-test, respectively. The long-term data were analyzed with the log-rank test and Kaplan-Meier curves. Mean age of the patients was 75±8.3years, and the average follow-up duration was 38±28.2months. There was no difference between the 2 groups regarding demographic data, risk factors except chronic renal insufficiency (30.6% in group 1 vs. 21.2%, P=0.011), and the proportion of obese patients (26.2% vs. 17.7%, P=0.02). Concerning the preoperative anatomic features, there was a significant difference between the groups concerning the length of the neck (25.5±10.1 vs. 28.3±12.6mm, P=0.008), the maximum diameter of the AAA (58±10.1 vs. 56.1±10.1mm, P=0.027), and the oversizing (18.1±8.3% in group 1 vs. 16.8±7.4% in group 2, P=0.043). There was no difference of the postoperative rates of complications, technical failure, endoleaks, and death. In the long run, analyses of survival showed that the rates of proximal endoleaks (13% vs. 3.9%, P<0.0001) and of reintervention (24.1% vs. 14.7%, P=0.009) were higher in group 1. There was no significant difference between the 2 groups regarding the evolution of the aneurysmal sac, the long-term rate of death from all causes or in relation to the aneurysm. Our results suggest that large stent grafts are more at the risk of proximal endoleak and reintervention in the long run. However, there were no differences observed in mortality or evolution of the aneurysmal sac in the patients treated by EVAR with wide neck during the period of follow-up.