Release patterns of pregnancy-associated plasma protein a in patients with acute coronary syndromes assessed by an optimized monoclonal antibody assay

Objective. Pregnancy-associated plasma protein A (PAPP-A) is expressed in eroded and ruptured atheromatous plaques, and circulating levels are elevated in acute coronary syndromes (ACS). Our objective was to investigate release patterns of PAPP-A in ACS and whether they differ among different types of ACS. Methods. In 40 patients, PAPP-A concentrations were measured in serially collected samples assessed by a novel ELISA technique. The patients were grouped according to type of ACS. Results. Release patterns for ST elevation myocardial infarction (STEMI) patients who underwent primary percutaneous coronary intervention (pPCI) showed a single substantial PAPP-A increase shortly after pPCI, followed by an abrupt return to normal levels without secondary peaks. STEMI, high-risk and low-risk non-ST elevation myocardial infarction/unstable angina pectoris (NSTEMI/UAP) patients without pPCI showed highly variable patterns with primary peaks followed by secondary PAPP-A increases. All patients with elevated PAPP-A levels reached the upper reference level within 24 h. There was a significant difference in median peak levels between STEMI (23.2 mIU/L) and low-risk ACS patients (6.35 mIU/L) (p=0.004) and between high-risk (median=15.3 mIU/L) and low-risk ACS patients (p=0.01). Among high-risk ACS patients, NSTEMI patients had significantly higher peak levels than UAP patients (p=0.003). Conclusion. PAPP-A serum levels increase above normal values within 24 h after onset of symptoms in ACS. There are significant differences in PAPP-A peak levels and release patterns across the spectrum of ACS patients.