Radial Artery Versus Saphenous Vein Patency (RSVP) Study

Arteries differ from veins both in morphology and physiology. Thus the way they behave as in vivo conduits when used in coronary artery bypass grafting is also likely to be different. This may partly explain the predisposition of veins used as coronary conduits to accelerated atherosclerosis in comparison with the internal mammary artery grafts. There are presently few data describing the properties of the radial artery as an in-vivo coronary conduit over the longer-term.

The study will compare angiographic patency of the radial artery or saphenous vein graft anastomosed to the native left circumflex coronary territory at 3 months and 5 years after surgery. A substudy will compare 5-year post-surgery diameter and blood flow of in-vivo radial artery and saphenous vein grafts in response to endothelium-dependent and non-endothelium-dependent stimuli when patients attend for their scheduled follow-up angiogram.

Inclusion criteria

• on waiting list for clinically-indicated myocardial revascularization surgery
• aged 40-70 years
• significant stenosis (≥70%) in the circumflex territory as identified on preoperative angiograms
• negative Allen's test (defined as the return of palmar circulation within 5 seconds of releasing ulnar artery compression)
• willing to give written informed consent

Exclusion criteria

• poor left ventricular (LV) function (LV ejection fraction <25%)
• severe diffuse peripheral vascular disease or bilateral varicose venous disease
• inability to comply with the angiographic follow-up at 3 months or/and 5 years