Infragenicular in situ vein bypass graft occlusion: a multivariate risk factor analysis

Early postoperative thrombosis and the later development of graft stenoses are the two major causes of vein bypass graft failure. The risk factors for both these outcomes were analysed in a multivariate analysis of 82 consecutive infragenicular in situ vein grafts. Twenty-four grafts failed within 30 days but eight were successfully revised. Technical errors accounted for six of the failures. A multivariate analysis revealed graft resistance > 1.4 peripheral resistance units (odds ratio 5.8, 95% C.I. 1.6-20) as the only independent risk factor for early graft failure. Eighteen grafts (27%) developed a stenosis most commonly in the distal third of the graft (46%). Poor quality, small diameter vein was the only independent risk factor for graft stenosis (odds ratio 7, 95% C.I. 1.5-34). Composite vein grafts, where narrowed and thickened vein had been replaced, had a significantly lower stenosis rate (difference in proportions 0.41, 95% C.I. 0.1-0.8, Mann-Whitney U test).