Accurate preoperative echocardiography has more impact on prediction of long-term mortality than intra-operatively measured flow in coronary bypass grafts

OBJECTIVE: Our study aimed to analyze the predictive value of intra-operative bypass graft flow measurements for long-term mortality. METHODS: A total of 1593 consecutive coronary artery bypass graft (CABG) patients routinely underwent intra-operative bypass graft flow measurements with the transit-time flow meter (TTFM: Cardiomed(®)). The results of the flow measurements and the demographics were analyzed retrospectively. RESULTS: The mean follow-up was 3.8 years (0.5-8.8 years) with no losses to follow-up. Overall mortality was 10.1%. The preoperative left ventricular ejection fraction (LVEF) (echocardiograph) was the highest independent predictor of long-term survival (hazard ratio 0.97, p = 0.004) in all groups. The univariate analysis for the CABG I group showed that besides LVEF, female gender (hazard ratio 3.6, p = 0.02) was also significant. For the CABG II group, additive EuroSCORE (European System for Cardiac Operative Risk) (ES) (hazard ratio 1.4, p = 0.0001) and age (hazard ratio 1.1, p = 0.001) were significant. In the CABG III group, ES (hazard ratio 1.2, p < 0.0001), age (hazard ratio 1.04, p = 0.001), IMA (hazard ratio 0.5, p < 0.0001) and concomitant aortic valve replacement (AVR) (hazard ratio 2.1, p = 0.03) were significant, in addition to the LVEF. CONCLUSION: With quality-controlled surgeons checked by intra-operative TTFM, accurate quantification of preoperative LVEF significantly predicts long-term outcome. Effective bypass graft flows failed to predict outcome in CABG patients, regardless of the degree of coronary artery disease (CAD) and concomitant AVR.