Prediction of graft patency using preoperative hyperemic and nonhyperemic intracoronary pressure indices in coronary artery bypass grafting

Objectives The hemodynamic significance of coronary artery stenosis is associated with graft patency in coronary artery bypass grafting. However, it remains unclear whether hyperemic or nonhyperemic intracoronary pressure indices better predict graft patency. This study aimed to compare the ability of intracoronary pressure indices to predict the graft patency of the in-situ internal thoracic artery (ITA) to the left anterior descending (LAD) artery. Methods This study included the patients who had the LAD artery evaluated with both hyperemic and nonhyperemic intracoronary pressure indices prior to surgery, underwent the in-situ ITA to LAD artery bypass, and subsequently underwent coronary computed tomography angiography to assess the graft patency postoperatively. The study endpoint was graft hypoperfusion, defined as either graft occlusion or graft string formation. Results Of the 105 patients, 10 patients (9.5%) showed graft hypoperfusion (occlusion; six patients, string; four patients). Patients with graft hypoperfusion had significantly less severe coronary artery stenosis determined by intracoronary pressure indices (fractional flow reserve (FFR): 0.74 vs 0.66; p = .013, nonhyperemic pressure ratio (NHPR): 0.88 vs 0.76; p < .01) and significantly lower intraoperative mean graft flow (16 vs 24 mL/min, p < .01) compared to those with patent grafts. Receiver operating characteristic curve analysis indicated that NHPR was more predictive of graft hypoperfusion than FFR (area under the curve: 0.74 vs 0.86, p = .049). Conclusion NHPR showed a greater ability to predict graft hypoperfusion in the ITA to LAD artery bypass than FFR.