Graft patency and determinants of outcome in infrainguinal bypasses - A retrospective study

Context: Chronic lower limb ischemia, an important marker of atherosclerosis, is a common clinical problem prevalent in all socioeconomic groups in our country and across the globe. Infrainguinal bypass is mandated in a subset of patients with critical limb ischemia to provide immediate limb salvage as well as excellent long-term results. Aim: The purpose of our retrospective study is to elucidate the effect of various known factors on the long term patency of infrainguinal bypass grafts performed in our patient population at a tertiary referral hospital. Methods: We retrospectively reviewed follow up data of 110 patients who had undergone infrainguinal bypass grafting over a period of ten years in our Institutional vascular registry. Graft patency rates and factors affecting thereof over this period were studied and the data statistically analysed. Overall cumulative patency rates were calculated by the life table survival method and compared with that of the patency rates of above-knee bypass procedures in the world literature. Patency rates in a different subset of patients were calculated and compared using the Wilcoxon (Gehan) test and Fisher's exact test to assess the influence of various factors in the long term outcome of the procedure. Results: Cumulative patency in terms of graft survival probabilities based on the life table analysis was 0.84, 0.80, and 0.64 at 30, 60, and 90 months respectively. Grafts in patients who had continued to smoke post-operatively had failed when compared with those who did not smoke (P = 0.01). Cumulative patency rates of non- diabetics were higher as compared to non-diabetics (0.70 vs 0.44; P = 0.04). Conclusion: Our study shows that continued smoking and diabetes are the determinant factors associated with graft occlusion. Strict avoidance of smoking and optimal control of diabetes is likely to improve graft function and long-term patency in patients undergoing infra-inguinal bypass grafting