The Role of Insulin-Like Growth Factor-1 and Pregnancy-Associated Plasma Protein-A in Diagnosis of Acute Coronary Syndrome and Its Related Morbidities

Introduction: Pregnancy-associated plasma protein-A (PAPP-A) is a metalloproteinase that plays a role in atherosclerotic plaque destabilization. In recent studies, insulin-like growth factor-1 (IGF-1) has been introduced as a mediator of atherosclerosis. PAPP-A and IGF-1 level may be important diagnostic indicators of acute coronary syndrome (ACS). Objective: The present study tried to assess the diagnostic role of IGF-1 and PAPP-A biomarkers in ACS spectrum. Methods: The serum level of IGF-1, PAPP-A and troponin I was determined in 121 consecutive patients with ACS. Relationships were assessed by t-test, ANOVA and the non-parametric equivalent. Accuracy of biomarkers was measured by the area under the ROC curve (AUC) and optimal cut-off points to diagnose STEMI and NSTEMI using Youden index. Results: In patients with acute ST segment elevation myocardial infarction (STEMI), all of these three biomarkers were significantly higher than those in patients with unstable angina (P=0.028 for IGF-1, P<0.001 for PAPP-A and Troponin-I). Mean level of IGF-1 in patients with renal failure was significantly higher than that in patients without renal failure (137.9 +/- 35.1 vs 105.1 +/- 46.9, P=0.003), but PAPP-A and serum Troponin-I level had no significant difference in renal failure groups (P>0.05). ROC curve analysis showed that after Troponin-I, PAPP-A was a good discriminator between patients with STEMI and patients with unstable angina (AUC=0.79). Optimum cut-off value for PAPP-A was found to be 89.2 ng/ml, with sensitivity and specificity of 66.7% and 83.8%, respectively. Conclusion: PAPP-A can be a novel biomarker for both identification of patients with STEMI and risk stratification in patients with ACS.