Graft flow evaluation with intraoperative transit-time flow measurement in off-pump versus on-pump coronary artery bypass grafting

Dror Ben Leviner; Carlo Maria Rosati; Miriam von Mücke Similon; Andrea Amabile; Daniel J F M Thuijs; Gabriele Di Giammarco; Daniel Wendt; Gregory D Trachiotis; Teresa M Kieser; A Pieter Kappetein; Stuart J Head; David P Taggart; John D Puskas

doi:10.1016/j.xjtc.2022.05.002

Graft flow evaluation with intraoperative transit-time flow measurement in off-pump versus on-pump coronary artery bypass grafting

JTCVS Tech. 2022 May 17:15:95-106. doi: 10.1016/j.xjtc.2022.05.002. eCollection 2022 Oct.

Affiliations

¹ Department of Cardiac Surgery, Carmel Medical Center, Haifa, Israel.
² Department of Cardiovascular Surgery, Mount Sinai Morningside, New York, NY.
³ Sackler School of Medicine New York State/American Program, Tel Aviv University, Tel Aviv, Israel.
⁴ Division of Cardiac Surgery, Department of Surgery, Yale University School of Medicine, New Haven, Conn.
⁵ Department of Cardiothoracic Surgery, Erasmus MC, University Medical Center, Rotterdam, The Netherlands.
⁶ Clinica Cardiochirurgica, Università"G. D'Annunzio" Chieti-Pescara, Chieti, Italy.
⁷ Department of Thoracic and Cardiovascular Surgery, West German Heart Center, Essen, Germany.
⁸ Heart Center, Veterans Affairs Medical Center, Washington, DC.
⁹ LIBIN Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada.
¹⁰ Department of Cardiovascular Surgery, University of Oxford, Oxford, United Kingdom.

Abstract

Objective: We aimed to compare transit-time flow measurement (TTFM) parameters for on-pump (ONCAB) and off-pump (OPCAB) coronary artery bypass procedures.

Methods: The database of the Registry for Quality AssESsmenT with Ultrasound Imaging and TTFM in Cardiac Bypass Surgery (REQUEST) study was retrospectively reviewed. Only single grafts were included (ie, no sequential or Y/T grafts). Primary end points were mean graft flow (MGF), pulsatility index (PI), diastolic fraction (DF), and backflow (BF). Unadjusted and propensity score-matching comparisons were performed.

Results: Of 1016 patients in the REQUEST registry, 846 had at least 1 graft for which TTFM was performed. Of these, 512 patients (60.6%) underwent ONCAB and 334 (39.4%) OPCAB procedures. Mean arterial pressure (MAP) during measurements was higher in the OPCAB group. After propensity score-matching, 312 well balanced pairs were left. In these matched patients, MGF was higher for the ONCAB versus the OPCAB group (32 vs 28 mL/min, respectively, for all grafts [P < .001]; 30 vs 27 mL/min for arterial grafts [P = .002]; and 35 vs 31 mL/min for venous grafts [P = .006], respectively). PI was lower in the ONCAB group (2.1 vs 2.3, for all grafts; P < .001). Diastolic fraction was slightly lower in the ONCAB group (65% vs 67.5%; P < .001). The backflow was also lower in the ONCAB group (0.6 vs 1.3; P < .001) with trends similar to MGF and PI for venous and arterial grafts. There were 21 (3.3%) revisions in the OPCAB group and 14 (2.1%) in the ONCAB group (P = .198).

Conclusions: ONCAB surgery was associated with higher MGF and lower PI values, especially in venous grafts. Different TTFM cutoff values for ONCAB versus OPCAB surgery might be considered.

Keywords: ACI, acoustic coupling index; BF, backflow; CABG, coronary artery bypass grafting; DF, diastolic fraction; LAD, left anterior descending; LIMA, left internal mammary artery; MAP, mean arterial pressure; MGF, mean graft flow; OM, obtuse marginal; ONCAB, on-pump coronary artery bypass; OPCAB, off-pump coronary artery bypass; PI, pulsatility index; PSM, propensity score matching; RA, radial artery; REQUEST, Registry for Quality AssESsmenT with Ultrasound Imaging and TTFM in Cardiac Bypass Surgery; RIMA, right internal mammary artery; SVG, saphenous vein graft; TTFM, transit-time flow measurement; coronary artery bypass grafting; flow; off-pump coronary artery bypass grafting; on-pump coronary artery bypass grafting; transit-time flow measurement.