Intraoperative assessment of coronary artery bypass graft: Transit-time flowmetry versus angiography

Background. Transit-time flowmetry has been used to assess graft status int raoperatively. This study examines the validity of this method by comparing its results with the findings of simultaneously performed graft angiograph y. Methods. The left internal thoracic artery (LITA) anastomosed to the left a nterior descending artery (LAD) was assessed intraoperatively with both tra nsit-time flowmetry and graft angiography in 30 patients. The patients were stratified into two groups based on intraoperative angiographic findings. In 18 patients (group A), the LITA and the LAD were well filled with contra st medium and the anastomosis was widely patent. In the other 12 patients ( group B), spastic LITA or LAD was observed. Postoperative angiography was a lso performed before discharge from the hospital. Results. The mean graft flow was 44.0 +/- 25.4 mL/min in group A and 23.4 /- 10.0 mL/min in group B (p = 0.0129). Diastolic-dominant flow pattern was observed in both groups, and the ratio of peak diastolic flow to peak syst olic flow and the percent diastolic time-flow integral were not statistical ly different between the groups. The pulsatility index was almost the same between the two groups and was acceptable in both. Postoperative angiograph y revealed that all grafts were patent without spasm or anastomotic stenosi s. Conclusions. LITA graft status is satisfactory when high graft flow with di astolic dominance is obtained. When there is vasospasm but no anastomotic p roblems, decreased graft flow with an acceptable pulsatility index and dias tolic augmentation is observed. (C) 2001 by The Society of Thoracic Surgeon s.