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Predicting early graft patency using transit-time flow measurement in internal thoracic artery-based composite
Min-Seok Kim1,2, Cheol Ho Lee1, Seong Wook Hwang1
1Cardiovascular Center, Myongji Hospital, Gyeonggi-do, Republic of Korea.
Insights
Transit-time flow measurement (TTFM) effectively predicts early graft patency after coronary artery bypass grafting (CABG) using internal thoracic artery (ITA)-based composite grafts. Intraoperative TTFM parameters accurately identify graft performance, ensuring better patient outcomes.
Area of Science:
- Cardiovascular Surgery
- Vascular Surgery
- Surgical Technology
Background:
- Coronary artery bypass grafting (CABG) relies on graft patency for success.
- Assessing graft function intraoperatively is crucial for preventing early graft failure.
- Internal thoracic artery (ITA)-based composite grafts are commonly used in CABG.
Purpose of the Study:
- To evaluate the predictive performance of intraoperative transit-time flow measurement (TTFM) parameters.
- To determine if TTFM can predict early graft patency after in situ ITA-based composite CABG.
- To establish optimal TTFM cutoff values for assessing graft flow categories.
Main Methods:
- A cohort of 274 patients undergoing isolated CABG with in situ ITA-based composite grafts was analyzed.
- Intraoperative TTFM parameters (MGF, PI, DF%, %BF) were recorded for each distal anastomosis.
- Early postoperative angiography was used to classify graft patency (perfectly patent, competitive, occluded).
- Receiver operating characteristic (ROC) curve analysis identified optimal cutoff values for TTFM parameters.
Main Results:
- Of 894 distal anastomoses, 81.0% were perfectly patent, 9.8% bidirectionally competitive, and 8.8% unidirectionally competitive.
- Significant differences in MGF, PI, DF%, and %BF were observed across graft-flow categories (P < .001).
- Optimal cutoff values were identified: MGF 10 mL/min, PI 3.1, DF% 60.0%, and %BF 5.0% for predicting competitive flow.
- Using all four thresholds predicted perfectly patent grafts with 91.8% PPV and functionally patent grafts with 97.3% PPV.
Conclusions:
- Intraoperative TTFM demonstrates strong predictive capability for early graft flow after composite CABG.
- Established TTFM parameters and cutoff values can reliably assess graft performance in this setting.
- This technique aids in optimizing graft selection and surgical technique to improve CABG outcomes.
Objective:
Intraoperative graft assessment is essential for early graft patency after coronary artery bypass grafting (CABG); however, interpretation of transit-time flow measurement (TTFM) parameters in internal thoracic artery (ITA)-based composite CABG remains unclear. This study evaluated whether intraoperative TTFM parameters predict early graft patency after composite CABG.
Methods:
We evaluated 274 patients who underwent isolated CABG using an in situ ITA-based composite graft and early postoperative angiography. TTFM parameters-mean graft flow (MGF), pulsatility index (PI), diastolic filling percentage (DF%), and percentage of backward flow (%BF) -were obtained for each distal anastomosis. Angiographic findings were classified as perfectly patent, bidirectionally competitive, unidirectionally competitive, or occluded. Receiver operating characteristic curve analyses determined optimal cutoff values and area under the curve (AUCs) for predicting competitive graft flow on early angiography.
Results:
Among 894 distal anastomoses (median 3 [3.0, 4.0] per patient), 724 (81.0%) were perfectly patent, 88 (9.8%) bidirectionally competitive, 79 (8.8%) unidirectionally competitive, and 3 (0.3%) occluded. MGF, PI, DF%, and %BF differed significantly across graft-flow categories (all P < .001). Optimal cutoff values for predicting competitive graft flow were MGF 10 mL/min (AUC, 0.725), PI 3.1 (AUC, 0.699), DF% 60.0% (AUC, 0.635), and %BF 5.0% (AUC, 0.707) (all P < .001). Simultaneous fulfillment of all 4 thresholds yielded positive predictive values of 91.8% for perfectly patent grafts and 97.3% for functionally patent (perfectly patent or bidirectionally competitive) grafts. Optimal cutoff values for MGF, DF%, and %BF did not differ between left and right coronary territories (P = .265, P = .673, and P = .321, respectively).
Conclusions:
Intraoperative TTFM demonstrated good predictive performance for early postoperative competitive graft flow in patients undergoing CABG using an in situ ITA-based composite graft.
