Association of coronary microvascular endothelial dysfunction with vulnerable plaque characteristics in early coronary atherosclerosis.

AIMS

The aim of this study was to test the hypothesis that coronary microvascular endothelial dysfunction (CMED) is associated with epicardial coronary atherosclerosis.

METHODS AND RESULTS

We performed a cross-sectional analysis of a comprehensive invasive assessment of coronary physiology with a focus on endothelium-dependent coronary microvascular function and virtual-histology intravascular ultrasound (VH-IVUS) in a total of 148 consecutive patients with chest pain and angiographically normal coronary arteries or non-obstructive coronary artery disease (CAD). Endothelium-dependent coronary vascular reactivity was evaluated by graded doses of intracoronary acetylcholine (ACh). CMED was defined as a percent increase in coronary blood flow of ≤50% in response to ACh. Patients with CMED (n=87) showed more vulnerable plaque characteristics as compared to those without (n=61); they showed higher plaque burden in association with larger necrotic core volume and higher frequency of imaged arteries containing at least one VH-IVUS-derived thin-capped fibroatheroma (TCFA) (n=22 [25.3%] vs 5 [8.2%], p=0.008). Multivariate logistic regression analysis revealed that CMED was an independent predictor of VH-IVUS-derived TCFA (adjusted odds ratio 2.28 [95% confidence interval: 1.30-4.02], p=0.004).

CONCLUSIONS

Independently of conventional coronary risk factors, CMED was associated with vulnerable plaque characteristics in patients with non-obstructive CAD.