Pregnancy-associated plasma protein-A as a marker of culprit lesion instability in unstable angina patients: an intravascular ultrasound study.

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.