Operative Techniques and Revascularization Strategies
The basic surgical procedures and strategies of OPCAB and harvesting technique of the SV have been previously described [5]. Saphenous vein harvest was performed using an open technique. The SV from a lower leg was chosen as opposed to the upper leg SV to decrease the possibility of size mismatch with native coronary arteries or ITA. Prior to October 2013, the NT SV was harvested without surrounding pedicle tissue, in which the manipulation and tension of the SV were minimized during harvest and manual intraluminal dilatation was avoided. The vein was gently separated from the bed using scissors, leaving small amount of perivascular adipose tissue in place. After October 2013, the NT SV was harvested with surrounding pedicle tissue, whereby the SV pedicle was harvested along with an approximately 3- to 5-mm wide margin of adjacent adipose tissues on both sides of the SV and thin layers of adherent connective tissues posteriorly, in addition to minimized manipulation and avoidance of manual intraluminal dilatation of the SV. Immediately after the harvest, the reversed SV was anastomosed to the side of the left ITA to construct a Y-composite graft or to the distal end of the left ITA to construct an I-composite graft. After the Y-composite graft was constructed, the left anterior descending coronary artery (LAD) territory commonly was revascularized first by using the left ITA while the distal end of the SV conduit was dilated spontaneously by the native flow and pressure of the left ITA. By using the SV as a composite graft, the left circumflex coronary artery (LCX) territory was then revascularized, followed by the right coronary artery (RCA) territory. A sequential anastomotic technique was used for complete revascularization when more than two coronary arterial anastomoses were needed. All the diseased left coronary territories that had had ≥70% diameter stenosis and the right coronary territories that had had ≥90% stenosis were considered for revascularization using SV composite grafts based on the left ITA.
We examined the anastomosis status with transit-time flow measurement (TTFM; Medi-Stim AS, Oslo, Norway) after performing each anastomosis and just before pericardial closure, and revised it if there was any abnormal finding in TTFM [6]. All patients received aspirin therapy (100mg daily) until the day of surgery and resumed it as soon as possible after surgery, usually 1 day postoperatively. Clopidogrel (75mg daily) was added simultaneously to aspirin for 1 year postoperatively. If the patient had a high blood level of low-density lipoprotein cholesterol (>70mg/dL), a statin therapy was initiated and maintained postoperatively.