Does perivascular fat influence neural control of the saphenous vein? Implications in coronary artery bypass surgery (CABG).

The saphenous vein (SV) is the most commonly used conduit for CABG but its patency rate is poor compared with the internal mammary artery (IMA). In conventional harvesting the saphenous vein's outer layer, the adventitia, is damaged and this affects the perivascular nerves. In addition the cushion of perivascular fat (PVF) surrounding the vein is removed. The performance of SV grafts removed with surrounding cushion of fat intact, using a no-touch technique, is markedly improved. This finding suggests that the outermost layers of the SV play a potentially important role in the success of this technique. In recent years there has been increasing interest in the potential ‘protective’ role of the PVF surrounding blood vessels. In this mini-review we discuss evidence for the beneficial role of PVF in the improved performance of SV grafts prepared using a ‘no-touch’ technique and put forward the hypothesis that PVF may affect the neural control of grafts and perhaps vice versa.