Influence of lipoproteins and antiplatelet agents on vein graft patency 1 year after coronary artery bypass grafting.

OBJECTIVE It remains unclear whether aggressive low-density lipoprotein cholesterol (LDL-C) management (<1.8 mmol/L) can slow the process of vein graft stenosis. This study aimed to explore the impact of baseline LDL-C levels on vein graft patency in patients on ticagrelor with or without aspirin 1 year after coronary artery bypass grafting (CABG). METHODS This was a post hoc analysis of the DACAB (Different Antiplatelet Therapy Strategy After Coronary Artery Bypass Graft Surgery) trial (NCT02201771), a randomized controlled trial (ticagrelor + aspirin or ticagrelor vs aspirin) of patients undergoing CABG in China. The study subjects were stratified as LDL-low (baseline LDL-C <1.8 mmol/L, 148 patients with 430 vein grafts) versus LDL-high (baseline LDL-C ≥1.8 mmol/L, 352 patients with 1030 vein grafts). The primary outcome was the 1-year vein graft patency (Fitzgibbon grade A) assessed by coronary computed tomographic angiography or coronary angiography. RESULTS Baseline/1-year LDL-C were 1.4/1.6 and 2.6/2.4 mmol/L in the LDL-low and LDL-high subgroups, respectively. Regardless of antiplatelet regimen, no significant inter-subgroup difference was observed for 1-year graft patency (LDL-low: 83.8% [359/430 grafts]; LDL-high: 82.3% [848/1030 grafts]; adjusted OR for non-patency [ORadj], 0.96; 95% confidence interval [CI], 0.62-1.50, P = .857). For both subgroups, the 1-year graft patency rates were greater with ticagrelor + aspirin versus aspirin (LDL-low: ORadj, 0.41; 95% CI, 0.17-0.97; LDL-high: ORadj, 0.38; 95% CI, 0.20-0.71; inter P = .679). CONCLUSIONS In general, baseline LDL-C is not associated with 1-year vein graft patency after CABG. Regardless of the baseline LDL-C levels, ticagrelor + aspirin was superior to aspirin alone in maintaining vein graft patency. The primary factor causing early vein graft disease might not be atherosclerosis but thrombosis.