TRANSIT-TIME FLOW MEASUREMENT FOR DETECTION OF EARLY GRAFT FAILURE DURING MYOCARDIAL REVASCULARIZATION

Background. A low-flow situation in arterial and venous grafts has bee n associated with high rates of perioperative infarction and mortality . This study was designed to look at intraoperative graft now and resi stance in patients with coronary artery disease. Methods. Coronary art ery bypass graft flow was measured in 46 patients. Transit-time now wa s used for coronary flow measurements at rest as well as after maximal vasodilation with adenosine infusion. Results. Forty-three of the 46 patients showed normal internal mammary artery graft now (>20 mL/min); 3 patients had no or minimal graft flow. Redoing the graft anastomosi s in these 3 patients resulted in normalization of graft now. The mean flow increased significantly after correction from 0.5 +/- 0.7 mL/min to 15.7 +/- 9.6 mL/min (p < 0.02). Conversely, vascular resistance de creased significantly from 138 +/- 10 to 4.8 +/- 1.8 Ohmv (p < 0.0001) , as did the pulsatiliity index (from 146.9 +/- 95.7 to 3.4 +/- 1.8; p < 0.001). After correction, coronary now reserve was 2.5 +/- 1.1. Con clusions. Measurements of intraoperative flow and resistance as well a s derived variables allow assessment of early graft function and thus help prevent graft failure and reduce perioperative infarction. Transi t-time volume now might be a simple tool for quality control in corona ry bypass procedures.