Preoperative Angiographic Washout and Coronary Artery Bypass Graft Patency

Coronary artery bypass graft (CABG) failure occurs in 3% to 30% of grafts by 1 year. Because graft flow depends on distal outflow, elevated microvascular resistance may predispose target vessels to graft failure.

The objective of the study was to determine whether quantitative target-vessel contrast washout from standard preoperative coronary angiography is associated with subsequent CABG patency.

This single-center retrospective study included 107 patients undergoing CABG from 2021 to 2024 with preoperative coronary angiography and postoperative graft imaging by invasive angiography or computed tomography angiography. A total of 201 bypassed target vessels were analyzed. Preoperative angiograms were segmented using a validated neural network, and contrast intensity profiles (CIPs) were generated after isolating each target-vessel runoff territory. CIP downslope was the primary washout variable. The primary outcome was graft failure, defined as graft occlusion or stenosis.

Among 201 bypassed target vessels, 152 remained patent and 49 met the criteria for graft failure. Each 1-SD shift toward a shallower CIP downslope was associated with higher odds of graft failure on univariable generalized estimating equations analysis (OR: 1.71; 95% CI: 1.19-2.47; P = 0.004) and after adjustment for age, sex, diabetes mellitus, and current smoking (OR: 1.77; 95% CI: 1.22-2.57; P = 0.003). Model discrimination was modest (area under the curve: 0.67; 95% CI: 0.62-0.78). A downslope threshold of -3,158 stratified graft patency, with faster washout associated with lower failure hazard (HR: 0.51; 95% CI: 0.28-0.90; log-rank P = 0.0193).

Automated quantification of preoperative angiographic contrast washout is feasible and associated with CABG patency, supporting CIP downslope as a potential angiography-derived marker of target-vessel outflow.