Intraoperative Transit-Time Flow Measurement and High-Frequency Ultrasound Assessment in Coronary Artery Bypass Grafting

Abstract OBJECTIVES We evaluated the impact of transit-time flow measurement (TTFM) with epicardial and epiaortic high frequency ultrasound (HFUS) in patients undergoing coronary artery bypass grafting (CABG). METHODS The REQUEST study is a multicenter, prospective study among 7 international centers performing CABG. The primary endpoint was any change in the planned surgical procedure. Major secondary endpoints consisted of i) the rate and reason for surgical changes related to the aorta, in-situ conduits, coronary targets, and completed grafts, and ii) the rate of in-hospital mortality and major morbidity. RESULTS Between April 2015 and December 2017, 1046 patients were enrolled. Of those, 1016 were included in the final analyses. Mean age was 65.9 years, 14.0% were female and diabetes was present in 39.6%. Off-pump procedures were performed in 39.6% and bilateral internal thoracic arteries in 30.5%. The primary endpoint occurred in 25.2% of patients (n=256) and in 77% (197/256) this was based on TTFM and/or HFUS. Surgical changes were related to the aorta in 9.9%, to in-situ conduits in 2.7%, and the coronary targets in 22.4%. Graft revision occurred in 7.8%, including revisions of the proximal and/or distal anastomosis in 6.6%. In-hospital adverse event rates were 0.6% for mortality, 1.0% for cerebrovascular events and 0.3% for myocardial infarction. CONCLUSION Surgical changes related to the aorta, conduits, coronary targets, and anastomosis were made in 25% of patients. This was associated with low operative mortality and low major morbidity. TTFM and HFUS may improve the quality, safety and efficacy of CABG and should be considered as a routine procedural aspect.