The internal thoracic artery (ITA) is established as the conduit of choice for revascularization of the LAD. However, the advantages of its use over that of the saphenous vein (SV) for revascularization of the RCX or RCA are still debated. From 11/01 to 08/03 intraoperative flow measurements were carried out in 462 consecutive patients (Euroscore 5.1) undergoing OPCAB (92% of isolated CABG during the same period, 3.7±1.0 distal anastomoses/patient). RCX was grafted in 380 patients[176 ITA (46%), 204 SV] and RCA in 392 patients [55 ITA (14%), 337 SV]. Mean pulsatile index (PI) was significantly better for the single ITA/RCx grafts (2.8±1.9; n=138) than for the single SV/RCx grafts (3.3±1.7, n=65; p<0.05). Mean flow did not differ (28±22 and 31±25ml/min; p=ns). Accordingly, the PI was significantly better for the single ITA/RCA grafts (2.2±1.2; n=55) than for the single SV/RCA grafts (3.4±2.6, n=268; p<0.05). The flow did not differ (30±16 and 32±22ml/min; p=ns). Early mortality and incidence of perioperative myocardial infarction were 1.5% (7/462) and 3.5% (16/462) for the whole patients. Incidence of perioperative myocardial infarction tended to be lower in patients receiving an ITA to either the RCx or the RCA than in those receiving a SV [3/138 of ITA/RCx (2.2%) vs. 3/65 of SV/RCx (4.6%), 2/55 of ITA/RCA (3.6%) vs. 13/268 of SV/RCA (4.9%)]. Matching better coronaries diameter, the ITA provides superior flow properties than the SV to the RCx and RCA regions with reduced perioperative ischemia. Whether this advantage persists after adjusting for the grade of the proximal coronary stenosis needs further studies.