A New Index of Intraoperative Transit-Time Flow Evaluation in Coronary Artery Bypass Grafting

(Division of Cardiovascular Surgery, Kasugai Municipal Hospital, Kasugai, Japan)

Yoshiyuki Takami Hiroshi Masumoto
It is essential to evaluate the quality of coronary artery bypass grafting (CABG) anastomosis in the operating room. Transit-time flow measurement has been increasingly used for this purpose, because it is less invasive, more reproducible, and less time consuming. The electrocardiogram-gated flow measurement has made it possible to identify the systolic flow (Qs) and diastolic flow (Qd) and to calculate a new index, diastolic filling index iDFI100∫Qd^m∫bQsb{∫bQdbnj for graft flow analysis. In this study, we investigated the clinical significance of DFI, together with other indexes, including mean flow (Qm), pulsatility index (PI)C% insufficiency (INSUF), and F0/H1, where F0 is a power of the fundamental frequency and H1 is a power of the first harmonic in spectral analysis by fast Fourier transformation of the flow curve. We examined the relationships of these intraoperative flow variables of the post-operative angiographic findings of 125 CABG grafts, including 58 in-situ internal thoracic arteries. There were significant differences between patent and non-patent grafts in all of the intraoperative flow parameters (Qm: 47.9}31.8ml/min vs 10.2}3.6ml/min, PI: 3.0}1.4 vs 9.6}2.4, INSUF: 3.3}4.2% vs 29.9}8.1%, F0/H1: 2.8}2.0 vs 0.6}0.2, DFI: 68.5}8.4% vs 38.2}17.2%). Our data suggested that a DFI value of more than 50% can be useful for surgeons to distinguish patent from non-patent grafts in the operating room, in combination with other parameters: Qm15 ml/min, PI5, INSUF15%, and F0/H1 ratio1.0.
@Jpn. J. Cardiovasc. Surg. 35: 5-9 (2006)