Long-term prognostic utility of PAPP-A and calprotectin in suspected acute coronary syndrome.

Background: Vascular inflammation plays a key role in the development of acute coronary syndrome (ACS). Pregnancy-associated plasma protein A (PAPP-A) and calprotectin are two of several novel promising markers of inflammation. The present study evaluates the prognostic utility of these two biomarkers in patients with suspected ACS.

Methods: Chest pain patients with suspected ACS (N = 871) were consecutively included in a prospective, observational study with a mean follow-up time of 84 months. Blood samples were drawn at admission, prior to treatment with heparin.

Results: Total mortality was 38.9%. In univariate analyses, high PAPP-A levels were associated with significant increased mortality. The hazard ratio [HR] in quartile (Q) 3 and Q4 were 1.57 (95% confidence interval (CI), 1.14-2.18), p = 0.006, and 1.41 [95% CI 1.02-1.97], p = 0.040, respectively, as compared to Q1. Calprotectin in the upper quartile (Q4) was associated with total mortality [HR1.94 (95% CI 1.42-2.66)], p = < 0.001, the combined endpoint of death or recurrent myocardial infarction (MI) [HR 1.68 (95% CI 1.26-2.24), p = < 0.001], and recurrent MI [HR 1.60 (95% CI 1.06-2.41); p = 0.024]. However, neither PAPP-A nor calprotectin was found to be an independent predictor of future adverse events.

Conclusion: In this study, high levels of PAPP-A and calprotectin were associated with adverse clinical outcome in chest pain patients with clinically suspected ACS. However, neither of the two biomarkers was an independent predictor of long-term prognosis.