Does a 'no-touch' technique result in better vein patency?

A best evidence topic was written according to a structured protocol. The question addressed was whether harvesting the saphenous vein (SV) as a conduit for coronary artery bypass grafting (CABG) using a no-touch technique would result in better patency rates. This technique involves the harvest of the SV with a pedicle of peri-vascular tissue left intact and the avoidance of distension of the vein prior to anastomosis. A total of 405 papers were found using the reported searches of which eight represented the best evidence to answer the clinical question. The authors, date, journal, study type, population, main outcome measures and results are tabulated. The studies found analysed the ultrastructural and mechanical properties of the endothelium and vessel walls of the two harvesting techniques; the protein and enzymatic expression and activity observed; the early atherosclerotic changes detected; and the overall patency of the grafts during short- and long-term angiographical follow-up. Three small prospectively randomised studies compared the patency of grafts harvested using the two techniques and found significant improvements in graft patency using the no-touch harvesting technique in comparison to both the conventional technique and more importantly comparable to the left internal thoracic artery (LITA) patency. The most favourable difference was that of graft patency after 8.5 years of follow-up [90% vs. 76% (P = 0.01), LITA patency 90%], and incidence of graft stenosis [11% vs. 25% (P = 0.006)]. These findings were supported by the demonstrated improvements in the cellular integrity of the vessels and the reduction in the mechanisms leading to graft failure seen in the no-touch harvested SV grafts. These morphological and cellular analyses were carried by five small comparative studies, demonstrating improved endothelial integrity and reduced injury, decelerated atherosclerotic processes, intact adventitial collagen layers, increase in the total area of vasa vasorum, elevated endothelial nitric oxide synthase expression and activity, and increased peri-vascular leptin levels and activity. We conclude that there are clear enhancements in vessel wall properties at a cellular level and angiographical evidence of superior graft patency when the no-touch SV harvesting technique is employed.