Pregnancy-associated plasma protein A: A biomarker in acute ST-elevation myocardial infarction (STEMI)

Background. Elevated circulating levels of pregnancy-associated plasma protein A (PAPP-A), a novel marker of atherosclerotic plaque instability, are associated with increased risk of future cardiac events in patients with acute coronary syndromes (ACS). However, little is known of the kinetics or clinical significance of circulating PAPP-A after plaque rupture in acute ST-elevation myocardial infarction (STEMI). Aim. To evaluate the 48-hour release of pregnancy-associated plasma protein A (PAPP-A) and its association with 12month outcome in patients with acute ST-elevation myocardial infarction (STEMI). Methods. Sixty-two consecutive STEMI patients were included (40 men and 22 women, median age 67.5 years (range 34-84)), of whom 54 (87.1%) received reperfusion therapy. PAPP-A was measured at admission and 6-12, 24 and 48 hours thereafter. In 14 patients, samples were obtained also at 1, 2 and 4 hours. Results. There was an early peak of circulating PAPP-A during the first 12 hours from symptom onset, followed by rapid normalization. A second, late PAPP-A elevation was noticed in 20/62 patients (32.3%). Admission PAPP-A > 10.0 mIU/L (highest tertile) was associated (P=0.049) with increased 12-month risk of cardiovascular death or non-fatal myocardial infarction. Moreover, the combination of failed early reperfusion together with late PAPP-A elevation was strongly (7/13 versus 10/49 patients, P= 0.016) associated with adverse outcome. Admission PAPP-A did not correlate with admission C-reactive protein or cardiac troponin I. Conclusions. PAPP-A is elevated early in STEMI and then declines rapidly, a pattern consistent with release from the ruptured plaque. The variability of PAPP-A kinetics at 48 hours reflects the success of reperfusion. This study also shows that PAPP-A may have prognostic value in STEMI.