Objective: Y-composite grafting with the radial artery (RA) is often used in off-pump coronary artery bypass grafting (OPCAB). However, the early flow reserve of the left internal thoracic artery (LITA) as a blood source of the Y-composite RA graft has not been delineated.
Methods: The size of the LITA was examined angiographically in 42 patients who underwent OPCAB using LITA and Y-composite RA grafting between June 2000 and February 2002. In these patients, the LITA was used as a blood source of the Y-composite RA graft. The mean patient age +/- SD was 67 +/- 8 years. The average number of d i stal anastomoses was 3.2 +/- 0.7. Total coronary revascularization was carried out in 34 patients with only LITA and Y-composite RA grafting. RA grafting was used for revascularization of the circumflex artery alone in 5 patients, for the right coronary artery system (RCS) alone in 6 patients, and for both the circumflex and the RCS in 23 patients. The average number of distal anastomoses using the RA was 1.9 +/- 0.7. Flow measurements of the proximal LITA were achieved intraoperatively with a transit-time flowmeter. The diameters of the LITA before and after the operation were measured angiographically. Intraoperative flow volume was correlated with the ratio of the LITA diameters before and after the operation.
Results: The mean flow rate of the LITA was 61 +/- 35 mL/min (range, 9-196 mL/min). The mean diameters of the LITA before and after the operation were 1.97 +/- 0.36 mm and 2.74 +/- 0.60 mm, respectively. The mean ratio of the LITA diameter after the opera t ion to that before the operation was 1.43 +/- 0.27. The intraoperative flow volume was positively correlated with the ratio of LITA diameters (r = 0.414; P =.006).
Conclusion: These results demonstrate the early adaptation of the LITA as a blood source of the Y-composite RA graft in OPCAB and the rationale for using the LITA as a single blood source for total coronary artery revascularization.