Transit time flow measurement of coronary bypass grafts before and after protamine administration

• Published in: Journal of cardiothoracic surgery Vol. 16; no. 1; p. 195
• Main Authors: Leviner, Dror B, von Mücke Similon, Miriam, Rosati, Carlo Maria, Amabile, Andrea, Thuijs, Daniel J F M, Giammarco, Gabriele Di, Wendt, Daniel, Trachiotis, Gregory D, Kieser, Teresa M, Kappetein, A Pieter, Head, Stuart J, Taggart, David P, Puskas, John D
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 09-07-2021; BioMed Central; BMC
• Subjects: Adult; Aged; Aged, 80 and over; Blood Flow Velocity; Bypass; Cardiovascular disease; Clinical trials; Coronary Artery Bypass; Coronary artery bypass grafting; Coronary Circulation; Coronary vessels; Female; Grafting; Heart surgery; Heparin Antagonists - therapeutic use; Humans; Intraoperative graft flow measurement; Male; Measurement; Middle Aged; Parameter identification; Patients; Protamine sulfate; Protamines - therapeutic use; Quality assessment; Quality control; Registries; Retrospective Studies; Statistical analysis; Surgery; Time measurement; Transit time; Ultrasonic imaging; Ultrasound imaging; Variables; Vascular Patency; Intraoperative graft flow measurement; Coronary artery bypass grafting; Quality control
• ISSN: 1749-8090; 1749-8090
• DOI: 10.1186/s13019-021-01575-y

Intraoperative graft assessment with tools like Transit Time Flow Measurement (TTFM) is imperative for quality control in coronary surgery. We investigated the variation of TTFM parameters before and after protamine administration to identify new benchmark parameters for graft quality assessment.
The database of the REQUEST ("REgistry for QUality AssESsmenT with Ultrasound Imaging and TTFM in Cardiac Bypass Surgery") study was retrospectively reviewed. A per graft analysis was performed. Only single grafts (i.e., no sequential nor composite grafts) where both pre- and post-protamine TTFM values were recorded with an acoustical coupling index > 30% were included. Grafts with incomplete data and mixed grafts (arterio-venous) were excluded. A second analysis was performed including single grafts only in the same MAP range pre- and post- protamine administration.
After adjusting for MAP, we found a small increase in MGF (29 mL/min to 30 mL/min, p = 0.009) and decrease in PI (2.3 to 2.2, p <  0.001) were observed after the administration of protamine. These changes were especially notable for venous conduits and for CABG procedures performed on-pump.
The small changes in TTFM parameters observed before and after protamine administration seem to be clinically irrelevant, despite being statistically significant in aggregate. Our data do not support a need to perform TTFM measurements both before and after protamine administration. A single TTFM measurement taken either before or after protamine may suffice to achieve reliable data on each graft's performance. Depending on the specific clinical situation and intraoperative changes, more measurements may be informative.
Clinical Trials Number: NCT02385344 , registered February 17th, 2015.