The Impact of Intraoperative Transit-Time Flow Measurement on Off-Pump and On-Pump Bypass Surgery Based on Three Months: A Propensity Score Matching Study

Background: The goal of this study was to investigate how transit-time flow measurement (TTFM) parameters influenced the success of coronary bypass surgeries using the on-pump coronary artery bypass (ONCAB) and off- pump coronary artery bypass (OPCAB) techniques and to compare the rates of early graft failure and major adverse cardiac and cerebrovascular events (MACCE). Methods: We retrospectively analyzed subjects who underwent coronary bypass surgery at our institution between 2017 and 2023 and compared the TTFM data of patients divided into two groups based on the surgical method: ONCAB and OPCAB. We compared the postoperative and first three months' MACCE data to assess the impact of TTFM on the two surgical methods. Results: Of the 2032 patients who underwent coronary bypass, we analyzed data from 1540 patients in the ONCAB group and 194 patients in the OP- CAB group. After propensity score matching, the TTFM data of 192 patients in both groups were compared. In the ONCAB group, a mean of 3.28 +/- 0.7 grafts per patient was used, while 2.22 +/- 0.6 grafts were used in the OP- CAB group (p = 0.001). TTFM identified problems with 19 (4.7%) grafts in the ONCAB group and 29 (8%) grafts in the OPCAB group, leading to their revision (p = 0.001). Overall, the pulsatile index (PI) values in the OPCAB group were significantly higher than in the ONCAB group. Hospital mortality was 3.1% in the ONCAB group and 2.6% in the OPCAB group (p = 0.286). MACCE and graft failure rates were similar in the first three months. Conclusions: Utilizing TTFM to assess graft quality during surgery enhances coronary bypass surgery in both ONCAB and OPCAB procedures. The enhanced results are particularly crucial for a process like OPCAB surgery, which necessitates the expertise and experience of a surgeon and is challenging to execute.