Value of serum pregnancy-associated plasma protein A for predicting cardiovascular events among patients presenting with cardiac chest pain

Background: Pregnancy-associated plasma protein A (PAPP-A) has been suggested as a candidate marker for the identification of unstable plaques in coronary arteries. We assessed the value of PAPP-A for predicting short-term cardiovascular events in a large cohort of patients presenting with cardiac chest pain. Methods: We included consecutive patients who presented to a teaching hospital in Germany with chest pain of cardiac origin confirmed by coronary angiography. We analyzed PAPP-A levels from serum samples drawn within 30 minutes after arrival in the emergency department or in the catheterization laboratory. Patients were followed for 90 days or until death for major adverse cardiovascular events, defined as the combined outcome of stent thrombosis, myocardial (re) infarction, ischemic stroke or cardiovascular-related death. Results: A total of 2568 patients (mean age [+/- standard deviation (SD)] 68 +/- 11 years; 74% male) presented with cardiac chest pain: 55% had stable angina and 45% had acute coronary syndrome. The PAPP-A levels ranged from 4 to 2154 mIU/L (median 14.0 mIU/L, interquartile range 9.3-25.2 mIU/L). Major adverse cardiovascular events occurred in 203 patients (7.9%). The mean PAPP-A level was higher among patients who had an event than among those who did not (62 +/- 156 v. 21 +/- 23 mIU/L, p < 0.001). In a multivariable analysis, PAPP-A remained a significant independent predictor of the primary outcome within 90 days (hazard ratio per 1 SD increase in PAPP-A level 1.96, 95% confidence interval 1.74-2.21). The optimal prognostic cutoff value was a PAPP-A level of 34.6 mIU/L. Interpretation: Higher levels of serum PAPP-A were independently associated with an in creased short-term risk of cardiovascular events in patients presenting with cardiac chest pain. Further studies are required to validate the use of PAPP-A in routine clinical practice to predict future cardiovascular events.