High-risk plaques in proximal and distal segments relative to graft anastomoses and non-grafted segments

Background: Coronary artery bypass grafting (CABG) is the preferred invasive treatment option for complex coronary artery disease (CAD), bypassing flow-limiting lesions and high-risk plaques (HRP), thereby reducing clinical events. It also provides graft collateralization, preventing cardiac events due to proximal plaque rupture or erosion, and vessel occlusion. This study evaluated the prevalence of HRPs in segments proximal and distal to graft anastomoses and in non-grafted segments, using coronary computed tomography angiography (CCTA) in patients with left main and three-vessel disease enrolled in the FASTTRACK CABG study. Methods: Coronary segments were categorized as proximal, distal, or non-grafted. Segments ≥1.5 ​mm on CCTA were screened for HRP features: low-attenuation plaque, positive remodelling, spotty calcification, and napkin ring. Minimal lumen area (MLA) and plaque burden at MLA were assessed in segments ≥3 ​mm in diameter. Perivascular adipose tissue attenuation was evaluated in major coronary arteries. Results: In 102 patients, 1767 segments were analyzed: 986 proximal, 348 distal, and 341 non-grafted. HRP prevalence was highest in proximal segments (45.13 ​% vs. 8.33 ​% distal vs. 28.74 ​% non-grafted, p ​< ​0.001). Non-grafted vessels with a Fractional Flow Reserve Computed Tomography (FFR_CT) ≥0.80 had High-Risk Plaques (HRPs) in 40.38 ​% of cases, compared to 32.58 ​% for those with an FFR_CT <0.80. The prevalence of HRPs between patients or vessels with graft occlusions and those without, was similar. Likewise, there was no significant difference in perivascular fat attenuation between patients and vessels with and without HRP. Conclusions: In patients undergoing CABG for complex CAD, surgery effectively bypassed most HRPs, however, a substantial proportion remained in non-grafted vessels. Trial registration: NCT04142021.