Factors affecting symptomatic vs asymptomatic vein graft stenoses in lower extremity bypass grafts

Abstract

Conclusions: Symptomatic vein graft stenosis is associated with the presence of distal vein graft lesions, alternative conduit grafts, and larger decreases in the ankle-brachial index (ABI). Graft patency after graft revision is not affected by whether the vein graft stenosis was or was not associated with symptoms. Summary: Stenosis of lower extremity vein grafts is often asymptomatic. This study was undertaken to characterize symptomatic vs asymptomatic vein grafts and to determine if the presence of symptoms influenced subsequent patency of vein grafts after revision. This was a retrospective analysis of a prospectively maintained database from a combined University and Department of Veterans Affairs Vascular Surgical Service. There were 219 lower extremity vein graft revisions performed in 161 patients between January 1995 and January 2007. Patients with vein graft stenoses were considered symptomatic if they had recurrence of the symptoms that had prompted the original placement of the vein graft. Both univariate and multivariate analysis were used to develop a model of independent predictors of symptomatic recurrence. Patency rates for symptomatic and asymptomatic stenotic vein grafts were compared after revision. There were 125 asymptomatic and 94 symptomatic vein graft lesions revised. Lesions associated with symptoms had a significantly greater drop in ABI than asymptomatic lesions (0.21 ± 0.03 vs 0.18 ± 0.02, P = .003). Vein graft stenoses that were located in the distal graft or in the outflow artery were also more likely to be associated with symptom recurrence (P = .048). By multivariate analysis, a decrease in ABI (odds ratio, 6.803; 95% confidence interval [CI], 1.418-32.258; P = .02) and use of alternative vein conduits (odds ratio. 2.633; 95% CI, 1.243-5.578; P = .01) were independent predictors of symptomatic vein graft stenosis. There were also strong trends towards symptomatic recurrence being associated with other systemic manifestations of atherosclerosis such as cerebrovascular disease or coronary artery disease (P = .06). Patients with diabetes or renal failure and current smokers were not more likely to present with recurrent symptoms. Symptomatic stenoses were more frequent in revisions performed between 1 and 2 years postoperatively (56%) than in the first year after the operation (37%, P = .003). Assisted primary patency rates of grafts revised with symptomatic vs asymptomatic stenoses were not different (82% symptomatic and 88% asymptomatic at 5 years; P = .30). Comment: The article defines, for the first time, factors associated with symptomatic vein graft stenoses. Unfortunately, although stenoses revised in alternative conduit grafts and stenoses revised >1 year after graft implantation are more frequently associated with symptoms, a significant number of patients in those groups also have asymptomatic graft stenosis of sufficient severity that the graft requires revision. At this time, a life-long policy of periodic surveillance of lower extremity vein grafts with duplex scanning still seems prudent.