Pedicled no-touch saphenous vein graft harvest limits vascular smooth muscle cell activation: the PATENT saphenous vein graft study

OBJECTIVE: Neointimal hyperplasia secondary to vascular smooth muscle cell (VSMC) activation limits the long-term patency of saphenous vein grafts (SVGs). We compared markers of vascular injury and VSMC activation in SVGs harvested using the pedicled 'no-touch' (NT) vs the conventional (CON) technique. METHODS: Patients undergoing coronary artery bypass surgery were enrolled in the PATENT SVG trial (clinicaltrials.gov NCT01488084). Patients were randomly allocated to have SVGs harvested with the NT technique from one leg and the CON method from the other. SVG segments underwent morphometry, histological and electron microscopy assessments and transcript measurements of VSMC activation and differentiation markers. Leg wound functional recovery and harvest site complications were assessed using a quality-of-life questionnaire. RESULTS: A total of 17 patients (65.3 +/- 7.3 years) were enrolled. SVGs harvested using the NT vs CON technique exhibited preserved intimal, medial and adventitial architecture. CON harvest was associated with greater medial Kruppel-like factor 4 transcript levels (0.26 +/- 0.05 vs 0.11 +/- 0.02, P < 0.05). CON samples had significantly lower medial serum response factor (0.53 +/- 0.11 vs 1.44 +/- 0.50, P < 0.05) and myocardin (0.59 +/- 0.08 vs 1.33 +/- 0.33, P < 0.05) transcript levels. MicroRNA-145, an inhibitor of VSMC activation and differentiation, was higher in the NT vs CON samples (1.84 +/- 1.03 vs 0.50 +/- 0.19, P < 0.05). Leg assessment scores were worse in the NT legs at 3 months, but similar to CON scores at 12 months. CONCLUSIONS: SVGs harvested using the 'NT' technique exhibit an early molecular and morphological pattern consistent with decreased VSMC activation compared with CON harvesting. Functional leg recovery was similar in both groups at 12 months. Larger studies are required to corroborate these findings.