Effect of evolocumab on saphenous vein graft patency after coronary artery bypass surgery (NEWTON-CABG CardioLink-5): an international, randomised, double-blind, placebo-controlled trial.

Background: Saphenous vein graft (SVG) failure remains a substantial challenge after coronary artery bypass graft (CABG). LDL cholesterol (LDL-C) is a causal risk factor for atherosclerosis, but its role in SVG failure is not well established. We evaluated whether early initiation of intensive LDL-C lowering with evolocumab could reduce SVG failure.

Methods: NEWTON-CABG CardioLink-5 was a multicentre, double-blind, randomised, placebo-controlled trial conducted at 23 sites in Canada, the USA, Australia, and Hungary. Eligible participants were adults (age ≥18 years) who underwent CABG with at least two SVGs and were being treated with statin therapy of moderate or high intensity. Participants were randomly allocated (1:1; variable block size) within 21 days of CABG to subcutaneous evolocumab 140 mg or placebo every 2 weeks. The primary endpoint was the 24-month vein graft disease rate (VGDR; the proportion of SVGs with ≥50% occlusion on coronary CT angiography or clinically indicated invasive angiography) in the modified intention-to-treat population. This trial is registered with ClinicalTrials.gov, NCT03900026, and is completed.

Findings: Between June 17, 2019, and Nov 10, 2022, 782 individuals were randomly assigned (389 to evolocumab and 393 to placebo). At baseline, among the 554 participants with primary outcome data available, the median age was 66 years (IQR 60-72), 471 (85%) of 554 participants were male and 83 (15%) were female, and the median LDL-C was 1·85 mmol/L (IQR 1·25-2·84) in the evolocumab group and 1·86 mmol/L (1·20-2·76) in the placebo group. Evolocumab resulted in a mean 48·4% placebo-adjusted reduction in LDL-C at 24 months (-52·4% vs -4·0%). The 24-month VGDR was 21·7% (149 of 686 grafts) in the evolocumab group and 19·7% (127 of 644 grafts) in the placebo group (difference 2·0% [95% CI -3·1 to 7·1]; p=0·44). Treatment was well tolerated, with similar adverse event profiles between the groups.

Interpretation: Among patients who underwent CABG, evolocumab did not reduce SVG disease at 24 months following the index surgery despite substantial LDL-C lowering. Further LDL-C lowering does not appear to meaningfully affect the pathophysiological mechanisms responsible for early SVG failure.

Funding: Amgen Canada.