Relation between N-terminal pro-B-type natriuretic peptide and coronary plaque components in patients with acute coronary syndrome: virtual histology-intravascular ultrasound analysis

Abstract

Background: The N-terminal pro-B-type natriuretic peptide (NT-pro-BNP) is a sensitive indicator of hemodynamic stress and its increased level is associated with higher mortality in acute coronary syndrome (ACS) patients. Virtual histology-intravascular ultrasound (VH-IVUS) can provide quantitative information on plaque components.

Methods: We measured preprocedural serum NT-pro-BNP levels in 156 ACS patients with preserved left ventricular systolic function and normal serum creatinine. VH-IVUS classified the color-coded tissue into four major components: fibrotic, fibro-fatty, dense calcium, and necrotic core (NC). Thin-cap fibroatheroma (TCFA) was defined as focal, NC-rich (>or=10% of the cross-sectional area) plaques being in contact with the lumen in a plaque burden of at least 40%. We divided the patients into two groups according to the NT-pro-BNP levels [group I: >or=200 pg/ml (n = 58) vs. group II: <200 pg/ml (n = 98)].

Results: The percent areas of NC at the minimum lumen site (19.8+/-13.1% vs. 15.2+/-11.1%, P = 0.027) and at the largest NC site (24.7+/-10.3% vs. 19.2+/-11.4%, P = 0.015) were significantly greater in group I than in group II. Percent NC volume was significantly greater in group I than in group II (15.8+/-8.1% vs. 10.1+/-9.1%, P = 0.008). The total number of TCFAs was 38 in group I and 56 in group II. The presence of at least one TCFA (58 vs. 38%, P = 0.009) and multiple TCFAs (25 vs. 10%, P = 0.005) within culprit lesions were observed more frequently in group I than in group II. The TCFAs were located more in proximal in group I than in group II [the length from coronary ostium to TCFA: 10.8+/-7.6 mm in group I vs. 25.7+/-16.3 mm in group II (P<0.001)]: 85% of TCFAs was located within 20 mm from coronary ostium in group I; conversely only 36% of TCFAs was located within 20 mm from coronary ostium in group II (P<0.001).

Conclusion: VH-IVUS analysis shows that ACS patients with high NT-pro-BNP levels had more vulnerable plaque component (more NC-containing lesions and higher frequency of culprit lesion TCFAs) and had more proximally located TCFAs.