Intraoperative graft flow measurement in coronary artery bypass grafting (CABG) is recommended, but its clinical impact is still controversial.

We evaluated the effect of Transient Time Flow Measurement (TTFM) on Major Cardiac Adverse Events (MACE) in CABG surgery.

Between January 2017 and February 2020, 959 patients underwent total arterial CABG with internal thoracic arteries (ITAs). Thirty-four patients with critical preoperative status according Euroscore II definition or redo procedures were excluded from the analysis. According to the surgeon preference, TTFM were assessed in 433 patients (TTFM) with Medistim system (Fig. 1). They were compared with 492 patients without TTFM assessment (No TTFM). Complete arterial revascularisation with single or bilateral ITAs with a Y-configuration was planned for all patients. Patients’ data were extracted from the French Society of Thoracic and Cardiovascular Surgery database (EPICARD). Primary end-point was the occurrence of MACE, including in-hospital cardiac mortality, perioperative myocardial infarction, cardiac arrest and the need for extra-corporeal membrane oxygenation (ECMO).

Preoperative characteristics, operative data and postoperative outcomes are resumed in Table 1. TTFM is associated with longer cardio-pulmonary bypass (CPB) times, because of supplementary time needed for measurement (82±24 vs. 78±25min., P=0.023). Five patients in TTFM group underwent graft revision because of unsatisfying flow values. MACE were significantly lower in TTFM group (2.1% vs. 5.7%, P<0.01). At multivariate analysis, TTFM was protective against MACE occurrence (OR 0.353, 95% CI 0.146–0.770, P=0.013). Other independent risk factors for MACE occurrence were cross clamp time (OR 1.18, 95% CI 1.03–1.35, P=0.016) and Euroscore II (OR 1.21, 95% CI 1.13–1.29, P<0.001).

TTFM reduces MACE occurrence and it should be mandatory for graft evaluation in coronary artery surgery.