Sequential Bypass Grafting on the Beating Heart: Blood Flow Characteristics

Background The sequential bypass technique is a routine method of myocardial revascularization. The aim of this study was to determine flow characteristics of individual and sequential bypass grafts created on the beating heart. Methods Between January 2003 and February 2004, a consecutive series of 50 patients underwent off-pump coronary bypass surgery with at least one venous sequential coronary graft. During the procedure, flow values and pulsatility indexes were measured in both segments of the sequential graft using a CardioMed transit time flow meter (CM 4008; Medi-Stim, Oslo, Norway). The flow values were simultaneously compared with those of individual venous grafts sutured to the same coronary arteries. Results The mean flow through the distal anastomosis (individual bypass; D1) was 37.4 mL/min, and this was not significantly influenced by the creation of a proximal sequential anastomosis (D2, 39.0 mL/min). In 32% of the patients, the sequential bypass was unwittingly connected proximally to a larger coronary bed; despite this, the flow in its distal segment was not less than that in the individual bypass. Conclusions The blood flow through an individual bypass is comparable with that through the distal segment (end-to-side anastomosis) of a sequential bypass. The grafting of a sequential bypass proximally to the larger artery (coronary bed) in sequence does not appear to have a significant effect on the blood flow in the distal segment of a sequential bypass.