Relative value of serum pregnancy-associated plasma protein A (PAPP-A) and GRACE score for a 1-year prognostication: A complement to calculation in patients with suspected acute coronary syndrome

Abstract

Background. The Global Registry of Acute Coronary Events (GRACE) study produced a scale for risk stratification in acute coronary syndromes (ACSs). Pregnancy-associated plasma protein A (PAPP-A) serum concentration was implicated as a marker of unstable atherosclerotic plaques. Objectives. We hypothesized that the measurement of the concentration of PAPP-A on admission may improve the stratification of cardiovascular risk in suspected ACS patients. Material and methods. We studied 70 patients with chest pain suggesting ACS diagnosis on admission. Serum cardiac biomarkers and PAPP-A were measured on top of the standard biochemical panel, and the GRACE risk score was calculated. A 12-month follow-up was completed to major adverse cardiac events (MACE): death, myocardial infarction (MI), need for percutaneous coronary intervention (PCI)/coronary artery bypass grafting (CABG), unplanned cardiovascular hospitalization. Results. In hospital/6-month GRACE, low risk was found in 35 patients (50%)/37 patients (53%), intermediate risk in 23 patients (33%)/21 patients (30%) and high risk in 12 patients (17%)/12 patients (17%). Mean PAPP-A was 39.64 mlU/L (standard deviation – SD 24.2), and median PAPP-A values for in hospital/6-month GRACE were 21.49 mlU/L (quartile 1st; 3rd – 13.41; 32.65) and 22.61 mlU/L (14.03; 34.1) for low risk patients, 51.76 mlU/L (35.18; 59.99) and 51.76 mlU/L (28.9; 62.1) for intermediate risk patients, and 68.82 mlU/L (58.54; 83.76) for high risk patients. The PAAP-A concentration with specific cut-off points had 66.7% positive predictive value (PPV) and 95.5% negative predictive value (NPV) for death, 33.3% PPV and 80.6% NPV for MI, 71.4% PPV and 57.1% NPV for any event. Intermediate and high in hospital/6-months GRACE had 14.3%/15.2% PPV and 100%/100% NPV for death, 34.3%/33.3% PPV and 94.3%/91.9% NPV for MI, 74.3%/72.7% PPV and 65.7%/62.2% NPV for any event. Conclusions. The PAPP-A serum concentration represents a promising prognostic biomarker with significantly improved PPV. The GRACE score is superior to stratification based on PAPP-A with regard to combined cut-off point for 1-year mortality.