Transient internal mammary artery graft stenosis on early angiography: navigating pitfalls in hybrid myocardial revascularization.

Objectives: Left internal mammary artery (LIMA) graft stenoses detected at early coronary angiography may be reversible and consequently prompt unnecessary graft revision. We aim to investigate the frequency, natural course, and clinical significance of internal mammary artery graft stenosis upon early angiography in patients undergoing hybrid myocardial revascularization.
Methods: In this retrospective sub-study of the Coronary Hybrid Revascularization Study, we compared graft appearance, ie, stenosis degree and flow, on early (in-hospital) and scheduled follow-up coronary angiography after 1 year. We assessed the change in graft patency using the Fitzgibbon classification (grade A: unimpaired runoff; grade B > 50% stenosis; grade O: occlusion), as well as graft association with adverse events (death, myocardial infarction, stroke, and repeat revascularization) at up to 5-year follow-up.
Results: We report clinical follow-up data for all 131 patients included in the Coronary Hybrid Revascularization Study. Change in graft patency was analyzed in 86 patients with satisfactory visualization of the LIMA graft on early and follow-up coronary angiography. All LIMA grafts were patent at discharge and follow-up. Twenty-seven of 37 (73%) grade B graft stenoses at early angiography resolved to grade A during follow-up of median 12 months (range, 8-83 months) after surgery. Angiographically significant graft stenoses at early coronary angiography were not associated with adverse clinical outcome up to 5-year follow-up.
Conclusions: Our results suggest that the majority of clinically silent LIMA graft stenoses resolve during follow-up and are not associated with adverse clinical outcomes.