Does completeness of revascularization affect clinical outcomes? Insights from REVIVED-BCIS2

Related Study: Impact of Anatomical and Viability-guided Completeness of Revascularization on Clinical Outcomes in Ischemic Cardiomyopathy
Published in Congress: EuroPCR 2024

Dr. Yücel Kanal

Introduction:
Ischemic cardiomyopathy (ICM) is the most common cause of heart failure (HF) and is associated with significant mortality and morbidity. While surgical revascularization has been shown to improve long-term outcomes in some patients, the surgery itself may also contribute to mortality. Percutaneous coronary intervention (PCI) may offer a better balance between risk and benefit. Complete revascularization of coronary disease has been associated with better outcomes in patients with preserved left ventricular (LV) function. However, the situation is less clear in patients with severe LV dysfunction. The aim of this study is to determine the effect of complete revascularization compared to optimal medical therapy (OMT) in patients with severe LV dysfunction.

Method:
REVIVED-BCIS2 is a prospective, multicenter, open-label, randomized controlled trial funded by the National Institute for Health Research in the United Kingdom. Patients with left ventricular ejection fraction (LVEF) ≤35%, extensive coronary artery disease (BCIS Jeopardy Score >6), and demonstrable myocardial viability (≥4 viable myocardial segments) were included. Patients who had a myocardial infarction within 4 weeks, decompensated heart failure, or continuous ventricular arrhythmias within 72 hours were excluded. The study population consisted of patients enrolled in the REVIVED-BCIS2 trial if baseline/procedural angiograms and viability studies were available for analysis by independent core laboratories. Completeness of revascularization, guided by anatomical and viability considerations, was measured using coronary and myocardial revascularization indices (RIcoro and RImyo), where RIcoro = [change in BCIS Jeopardy Score (BCIS-JS)] / [baseline BCIS-JS] and RImyo = [number of revascularized viable segments] / [number of viable segments supplied by diseased vessels]. The PCI group was classified as having complete or incomplete revascularization based on median RIcoro and RImyo values. The primary outcome was death or hospitalization for heart failure. A total of 700 patients were randomized, with 670 patients included in the anatomical revascularization group and 619 patients in the viability-guided revascularization group after excluding ineligible patients. Viability of tissues was determined by cardiac magnetic resonance imaging (CMR) and dobutamine stress echocardiography. Significant coronary lesions were defined as >50% in the left main coronary artery (LMCA) and >70% in non-LMCA lesions.

Results:
Baseline BCIS-JS and SYNTAX scores were 8 (6 to 10) and 22 (15 to 29), respectively. In patients assigned to PCI, median RIcoro and RImyo values were 67% and 85%, respectively. There was no difference in the likelihood of the primary outcome in those receiving complete anatomical or viability-guided revascularization compared to the group assigned to OMT alone (HR 0.90, 95% CI 0.62-1.32 and HR 0.95, 95% CI 0.66-1.35, respectively). Sensitivity analysis based on residual SYNTAX score showed no association with the outcome.

Conclusion:
In patients with severe left ventricular dysfunction, neither complete anatomical nor viability-guided revascularization was associated with improved event-free survival compared to incomplete revascularization or treatment with medical therapy alone.

Commentary:
Many studies in stable coronary artery disease (CAD) patients have shown no mortality benefit of revascularization compared to OMT. However, there are several studies indicating an increase in LVEF following revascularization in patients with low LVEF and viable tissue, which has puzzled interventional cardiologists in this patient group. In the CULPRIT-SHOCK study conducted in acute coronary syndrome patients, intervention on the culprit lesion was compared with complete revascularization, and better outcomes were observed in the group where the culprit lesion was intervened. There is no randomized study comparing complete and incomplete revascularization in stable lesions. Therefore, this study provides us with an important message. However, bias may exist due to non-blinding in patient selection in the study. The lack of use of intracoronary physiological or imaging methods such as fractional flow reserve (FFR), intravascular ultrasound (IVUS), or optical coherence tomography (OCT) to determine lesion severity in patients is also a significant limitation. Therefore, multicenter, randomized studies with blinded patient selection, including patients undergoing revascularization using intracoronary physiological or imaging methods, are needed for us to make definitive conclusions in this patient group.