Concomitant Coronary Atheroma Regression and Stabilization in Response to Lipid-Lowering Therapy.

BACKGROUND

The frequency, characteristics and outcomes of patients treated with high-intensity lipid-lowering therapy and showing concomitant atheroma volume reduction, lipid content reduction, and increase in fibrous cap thickness (i.e., "triple regression") are unknown.

OBJECTIVES

This study was designed to investigate rates, determinants and prognostic implications of triple regression in patients presenting with acute myocardial infarction (AMI) and treated with high-intensity lipid-lowering therapy.

METHODS

The PACMAN-AMI trial employed serial intravascular ultrasound, near-infrared spectroscopy, and optical coherence tomography to compare the effects of alirocumab vs. placebo in patients receiving high-intensity statin therapy. Triple regression was defined by the combined presence of percent atheroma volume (PAV) reduction, maximum lipid core burden index within 4 mm (maxLCBI4mm) reduction, and minimal fibrous cap thickness (FCT) increase. Clinical outcomes at one-year follow-up were assessed.

RESULTS

Overall, 84 (31.7%) patients showed triple regression (40.8% in the alirocumab group vs. 23.0% in the placebo group, p=0.002). On-treatment low-density lipoprotein cholesterol levels were lower in patients with vs. without triple regression (between-group difference -27.1 [-37.7 to -16.6] mg/dl, p<0.001). Triple regression was independently predicted by alirocumab treatment (odds-ratio [OR] 2.83, 95% confidence interval [CI] 1.57-5.16, p=0.001) and a higher baseline maxLCBI4mm (OR 1.03, 95%CI 1.01-1.06, p=0.013). The composite clinical endpoint of death, myocardial infarction and ischemia-driven revascularization occurred less frequently in patients with vs. without triple regression (8.3% vs. 18.2%, p=0.04).

CONCLUSIONS

Triple regression occurred in one third of AMI patients receiving high-intensity lipid-lowering therapy and was associated with alirocumab treatment, higher baseline lipid content and reduced cardiovascular events.