Transit Time Flow Measurement In Robotic Totally Endoscopic Coronary Artery Bypass (tecab): What Do The Numbers Mean?
Benjamin Yang, Sarah Nisivaco, Gianluca Torregrossa, Husam Balkhy.
University of Chicago, Chicago, IL, USA.
BACKGROUND: Transit-time flow measurement (TTFM) is valuable for assessing intraoperative graft patency in coronary artery bypass surgery. The significance of competitive native coronary flow (as predicted by % backflow on TTFM) on patency is unknown. This study aims to evaluate intraoperative TTFM parameters in predicting graft patency in robotic TECAB. METHODS: We reviewed TTFM parameters in 311 patients who underwent robotic off-pump TECAB at our institution between 2/2016 and 1/2020. Sequential or Y-grafts were excluded, leaving 277 patients with a total of 387 isolated end-to-side grafts (248 LIMA and 149 RIMA). Mean graft flow, pulsatility index, % backflow, and diastolic index were measured in all grafts. Post-operative angiograms were obtained in patients undergoing hybrid coronary revascularization and a total of 154 grafts were imaged (99 LIMA and 55 RIMA). Angiograms were independently analyzed and separated into patent (Fitzgibbon A and B) and non-patent (Fitzgibbon O) groups. RESULTS: Angiographic follow-up at a median of 37.5 days after surgery showed a 147 (95.5%) patent grafts and 7 (4.5%) occluded grafts in both LIMA and RIMA grafts to both LAD and non-LAD targets. 73 of 76 LIMA-LAD grafts were patent (96.1%). Mean graft flow in all grafts was 74.5 ± 36.0 ml/min. Transit time flow measurements showed no difference in mean flow, pulsatility index, or % backflow between the two groups. Previously published parameters predictive of early graft failure (mean graft flow < 15 ml/min, pulsatility index > 3, % backflow > 3%) were not associated with graft failure in our study cohort. Median time between surgery and angiogram was longer in the group of occluded grafts (Figure 1). CONCLUSIONS: Excellent intraoperative flow parameters and early angiographic patency can be obtained via a robotic, off-pump totally endoscopic approach to coronary artery bypass. Our initial data did not demonstrate an association between intraoperative TTFM values (and specifically presence of competitive native coronary flow) and early angiographic graft outcomes.
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