Predictive Role of Myocardial Fibrosis Severity on Functional Recovery following Coronary Revascularization

Abstract

Background: There is variable functional recovery following coronary revascularization in patients with ischemic left ventricular dysfunction. The degree of myocardial fibrosis could affect the recovery of myocardial function following restoration of coronary blood flow.

Objective: To determine the predictive role of myocardial fibrosis severity in functional recovery following coronary revascularization.

Methods: This was a prospective observational cohort study of 120 patients with obstructive coronary artery disease and left ventricular ejection fraction of 45% or lower undergoing percutaneous coronary intervention and/or coronary artery bypass surgery from January 2022 to March 2023. Pre-revascularisation cardiovascular magnetic resonance (CMR) with late gadolinium enhancement (LGE) was performed. Fibrosis was classified as mild, moderate and severe. The criterion for functional recovery was an absolute improvement of ≥ 5% in LVEF at 6 months.

Results: Functional recovery occurred in 66 patients (55.0%). There was a recovery rate of 80.0% in mild fibrosis, 57.8% in moderate fibrosis and 22.9% in severe fibrosis (P<0.001). Mean ejection fraction improvement was 9.0±5.1, 5.6±5.0, and 1.6±4.3 percentage points, respectively. The adjusted odds of recovery decreased by 40% for every 5% increase in fibrosis burden (adjusted odds ratio 0.60, 95% confidence interval 0.48–0.75, p<0.001). Better functional recovery was also independently related to complete revascularization.

Conclusion: The severity of myocardial fibrosis was an independent predictor of functional recovery after coronary revascularization. Preprocedural fibrosis assessment may enhance prognostic evaluation, patient counselling and post-revascularization management.

Keywords: myocardial fibrosis; coronary revascularization; functional recovery; late gadolinium enhancement; ischemic cardiomyopathy.