Venous External Support in Coronary Artery Bypass Surgery: A Systematic Review and Meta-Analysis.

Neointimal hyperplasia and lumen irregularities are major contributors to vein graft failure and the use of VEST should prevent this. In this review, we aim to evaluate the angiographic outcomes of externally supported vein grafts. Medline, Embase and Cochrane Library were systematically reviewed for randomized clinical trials published by August 2022. The primary outcome was graft failure. Secondary outcomes included graft ectasia, intimal hyperplasia area and thickness, and graft nonuniformity. Odds ratios (OR) for dichotomous variables and mean difference (MD) for continuous variables with 95% confidence intervals (CI) were pooled using a fixed-effects model. Three randomized controlled trials with a total of 437 patients were included with follow-up ranging from 1 to 2 years. The odds of graft failure were similar in the 2 groups (OR 1.22; 95%CI 0.88-1.71; I² = 0%). Intimal hyperplasia area [MD -0.77 mm; 95%CI -1.10 to -0.45; I = 0%] and thickness [MD -0.06 mm; 95% CI -0.08 to -0.04; I=0%] were significantly lower in the VEST group. Fitzgibbon Patency Scale of II or III (representing angiographic conduit nonuniformity; OR 0.67; 95%CI 0.48-0.94; I = 0%) and graft ectasia (OR 0.53; 95%CI 0.32-0.88; I = 33%) were also significantly lower in the VEST group. At short-term follow-up, VEST does not seem to reduce the incidence of graft failure, although it is associated with attenuation of intimal hyperplasia and nonuniformity. Longer angiographic follow-up is warranted to determine whether these positive effects might translate into a positive effect in graft failure and in long-term clinical outcomes.