Correlates of saphenous vein graft hyperplasia and occlusion 1 year after coronary artery bypass grafting: analysis from the CASCADE randomized trial

Abstract

Background: Intimal hyperplasia of saphenous vein grafts (SVGs) can lead to subsequent graft atherosclerosis and occlusion after coronary artery bypass grafting (CABG). This study examined whether patient characteristics, anatomic factors, and medications are associated with SVG intimal hyperplasia and occlusion after CABG.

Methods and results: We performed a post hoc analysis of the Clopidogrel After Surgery for Coronary Artery Disease (CASCADE) trial, where 322 grafts were assessed by angiography and 90 grafts were examined by intravascular ultrasound at 1 year after CABG. We assessed the following correlates for intimal hyperplasia and occlusion: patient characteristics, discharge medications, target vessel characteristics, and SVG diameter. At 1 year, the SVG mean intimal area was 4.3 ± 2.1 mm(2), and the occlusion rate was 6.2% (13/209). Independent correlates of hyperplasia were larger SVG diameter (1.9 ± 0.2 mm(2)/mm; P<0.001), hypertension (0.7 ± 0.3 mm(2); P=0.03), and grafting to the right coronary territory (0.6 ± 0.3 mm(2); P=0.03), whereas statin (-0.8 ± 0.3 mm(2); P=0.01) and β-blocker use (-1.0 ± 0.4 mm(2); P=0.03) were associated with less hyperplasia. Low target vessel quality was an independent correlate of SVG occlusion (odds ratio, 5.2 ± 3.1; P<0.01).

Conclusions: Hypertension, SVG diameter, grafting to the right coronary artery, and low quality of the target vessel correlate with the development of SVG hyperplasia or occlusion by 1 year after CABG, whereas β-blockers and statins are associated with less SVG disease. These new findings further our understanding of SVG remodeling after bypass surgery and may guide future research to help prevent post-CABG SVG disease.

Clinical trial registration url: http://www.clinicaltrials.gov. Unique identifier: NCT00228423.

Keywords: coronary artery bypass surgery; hyperplasia; saphenous vein; β-blockers, adrenergic.