Graft revision after transit time flow measurement in off-pump coronary artery bypass grafting

Objective: To determine whether coronary graft patency can be predicted by transit time flow measurement (TTFM). Methods: From May 1 1997 to December 31 1998, TTFM was prospectively evaluated in 409 patients undergoing coronary artery bypass grafting (CABG) without cardiopulmonary bypass (CPB). All grafts (1145) were tested with TTFM. Results: Thirty-seven out of 1145 grafts (3.2%) were revised in 33 patients (7.6%). In six cases (18.1%) use of CPB was necessary during revision due to hemodynamic instability. The remaining patients underwent revision off-pump. Thirty-four grafts (91.9%) were revised for both low flow and abnormal flow curve patterns. Findings at revision included: thrombosis of the anastomosis (n = 6), stenosis at the toe or heel of the anastomosis (rt = 8), coronary flap or dissection (n = 5), dissection of the internal mammary artery (n = 5), graft kinking (n = 4), flap at proximal anastomosis (n = 1), coronary stenosis distal to the graft (n = 3), and no findings (n = 2). After revision all flow values and flow patterns improved. Although three additional grafts (8.1%) were revised for low flow (<7 ml/min) despite normal flow patterns, there were no findings at revision and flow values and curves remained unchanged after revision. Postoperatively, one patient developed a stroke (3%), one had an acute myocardial infarction (MI) (3%), one had a sternal wound infection (3%), and one required prolonged ventilatory support (3%). Conclusion: Evaluation of TTFM is valuable in determining the status of a coronary graft after CABG. Correct interpretation of flow patterns allows for correction of abnormalities prior to chest closure. (C) 2000 Elsevier Science B.V. All rights reserved.