Pregnancy-Associated Plasma Protein-A as a Marker of Culprit Lesion Instability in Unstable Angina Patients: An Intravascular Ultrasound Study

Abstract

Background: We evaluated the relationship between pregnancy-associated plasma protein-A (PAPP-A) and coronary plaque instability as assessed by intravascular ultrasound (IVUS). Methods: We performed greyscale IVUS analysis in culprit lesions of 93 patients with unstable angina (UA) and 72 with stable angina (SA). A sandwich enzyme-linked immunosorbent assay technique was used to assay circulating PAPP-A. Results: Patients with UA had higher PAPP-A levels than those with SA 10.8 mIU/l [interquartile range (IQR) 8.3-14.4] vs. 5.4 (IQR 2.9-9.8) mIU/l, p < 0.001]. Lesions in patients with higher PAPP-A levels were associated with larger plaque burden than lesions in patients with lower PAPP-A levels. IVUS attenuated plaque, positive remodeling and plaque rupture. Thrombus and angiographic Ambrose type-II eccentric lesions or multiple irregularities were more common in patients with higher PAPP-A levels than in those with lower PAPP-A levels. They were also more common in patients with UA and higher PAPP-A levels than in patients with (1) SA and higher PAPP-A levels, (2) UA and lower PAPP-A levels or (3) SA and lower PAPP-A levels. Conclusions: Higher PAPP-A levels were associated with coronary plaque instability in vivo and unstable symptoms in patients with coronary artery disease.

Level of Pregnancy-associated Plasma Protein-A Correlates With Coronary Thin-cap Fibroatheroma Burden in Patients With Coronary Artery Disease

“…24 In in vitro studies, PAPP-A has been demonstrated to be a specific activator of insulin-like growth factor-I (IGF-I), which stimulates migration and proliferation of smooth muscle cells, production and accumulation of foam cells, and degradation of extracellular matrix. 25–27 Our previous grayscale-IVUS study demonstrated that higher circulating PAPP-A levels were associated with echo-attenuated plaques, 28 a grayscale IVUS marker of plaque instability. 6,29 Grayscale IVUS, however, is limited to tissue characterization, especially for necrotic core-rich plaques.…”