Coronary Artery Bypass Grafting Transit-Time Flow Measurement: Graft Patency and Clinical Outcomes.

Abstract Background This Randomized On-Off Bypass (ROOBY) Trial sub-analysis examined transit time flow measurement (TTFM) use and its impact on graft patency and long-term clinical outcomes after coronary artery bypass grafting (CABG). Methods TTFM use for ROOBY centers and surgeons was assessed. Comparative patient outcomes, based on TTFM use, included 1-year graft patency and 1-year and 5-year major adverse cardiac events (MACE): all-cause mortality, non-fatal myocardial infarction (MI), and revascularization (percutaneous coronary intervention (PCI) or repeat CABG). Results TTFM was used in 1,067 patients (TTFM group) and not used in 501 patients (non-TTFM group); of the TTFM group, median percentage TTFM use was 82% (IQR 53-98%) among 18 VA centers and 78% (IQR 9.2-97%) among 44 surgeons. Patients were comparable in age (63 ±8.5 TTFM vs. 62 ±8.0 non-TTFM; p=0.30) and estimated 30-day mortality risk (1.8±1.7 TTFM vs. 1.9 non-TTFM, p=0.53). One-year Fitzgibbon A patency was 83 % (1600/1988 grafts) for TTFM assessed grafts and 78% (629/803) for non-TTFM assessed grafts (p Conclusions The association of TTFM use with graft patency and clinical outcome is uncertain. Future, randomized studies which account for patient risk factors and practice variation would help address this knowledge gap.