External Stenting of Vein Grafts Is Safe and Effective: Single-Center Report from the Multicenter Randomized VEST III Trial

Objective: Progressive saphenous vein graft (SVG) disease is still the main limitation of the long term clinical outcome of CABG. External stenting of vein grafts has the potential to reduce disease development and progression over the long term. First studies in humans have optimized the implantation technique and have shown its potential to significantly mitigate intimal hyperplasia, reduce oscillatory shear stress and improve SVG lumen uniformity 1 year after CABG. The VEST III trial is designed to evaluate whether external SVG stenting inhibits disease progression (intimal hyperplasia and lumen irregularities) 2 years after CABG. The current interim study objective is to assess the early patency of stented and non-stented SVGs 6 months after CABG.

Methods: 35 CABG patients with multi-vessel disease were enrolled in the VEST III trial at our hospital. In addition to an internal mammary artery graft, each patient received one external stent to a single SVG randomized to either the right or left coronary territories while one or more non-stented SVG served as control(s). Graft patency was confirmed at 6 months using CT angiography.

Results: A total of 35 patients (mean age 66.0 ± 7.1 years, 97% males) were enrolled in Trier between 10/2015 and 1/2017. External stent deployment was successful in 100% of patients. All SVG were harvested in an open manner. Baseline grafting parameters, such as host coronary artery diameter and graft length, were similar between the stented and non-stented groups. During surgery, transient time flow measurements and pulsatility indices in the stented and non-stented groups were 36.1 ± 14.8 and 2.0 ± 0.8 and 37.42 ± 15.2 and 2.3 ± 1.3 respectively. Over all MACCE rate was 14.3% during the reported study period (mean follow up 481 days, range 229–681 days). To date, 6 month CT angiography has been completed for all 35 patients (100% follow-up). The total number of grafts was 105 of which 103 are patent (98.1%). Early patency of LIMA grafts was 97% (34/35). Early patency of stented SVG to the right and left territories were 100% (17/17) and 100% (18/18) respectively compared with 100% (18/18) and 94.4% (17/18) in the non-stented group

Conclusion: External stenting of SVG safe and adds no additional risk for midterm patency. In the long-term follow-up of this trial, coronary angiography with IVUS will be used to determine the efficacy of external stenting in the reduction of intimal hyperplasia and vein graft degeneration.