Pregnancy-Associated Plasma Protein A as Predictor of Outcome in Patients With Suspected Acute Coronary Syndromes

We read with interest the article by Lund et al 1 on circulating pregnancy-associated plasma protein A (PAPP-A) in 136 patients evaluated for suspected acute coronary syndrome without cardiac troponin I elevation. PAPP-A concentrations above 2.9 mIU/L during the first 24 hours independently predicted cardiovascular death, nonfatal myocardial infarction, or revascularization over the following 6 months. The risk ratio of PAPP-A 2.9 mIU/L, adjusted for C-reactive protein (CRP), age, gender, diabetes, current smoking, hypertension, previous myocardial infarction, and congestive heart failure was superior to that of CRP 2 mg/L: 4.6 for PAPP-A (95% confidence interval 1.8 to 11.8, P0.002) versus 2.6 for CRP (95% confidence interval 1.1 to 6.5, P0.03). The cumulative risk of an event, graded by increasing PAPP-A values, was 8% in the lowest group and 37.9% in the highest (P0.0012). PAPP-A and CRP levels were independent of each other (r0.03, P0.7 on admission; r0.02, P0.8 for peak values). These striking data are discussed only briefly by the authors, who, despite showing a lack of correlation between PAPP-A and CRP, propose PAPP-A as a mediator of the inflammatory reactions that would lead to plaque rupture and clinical instability.