Low Protein Z Level: A Thrombophilic Risk Biomarker for Acute Coronary Syndrome.

Acute coronary syndrome (ACS) encompasses a range of thrombotic coronary artery diseases. Protein Z (PZ)/PZ-dependent protease inhibitor complex is a natural anticoagulant system with a presumptive role for PZ deficiency in the pathogenesis of ACS. We aimed to evaluate plasma PZ level and role as a risk biomarker in Egyptian patients with ACS. Hundred patients with stable ACS and 60 matched controls were enrolled. ACS patients were divided into 3 clinical subgroups (ST-segment elevation myocardial infarction, non-ST-segment elevation myocardial infarction, and unstable angina), and 2 age subgroups (group A ≤ 55 years, and group B > 55 years). Plasma PZ levels were evaluated using enzyme linked immunosorbent assay. Lower PZ levels were found in ACS patients' group and clinical subgroups compared with controls. PZ levels showed a decrease with increasing age and were lower in females versus males. Lower PZ levels were found in hypertensive ACS patients in both age subgroups. Smokers and patients with family history of ACS in group A had lower PZ levels, while group B revealed lower PZ among diabetic patients. In group A, increased number of ACS conventional risk factors was associated with lower PZ levels. PZ level 3.7 μg/mL was the best cut-off value for prediction of ACS. Logistic regression analyses approved PZ as an independent risk biomarker for ACS. PZ levels are reduced in stable ACS and are significantly and independently associated with increased susceptibility for ACS, denoting PZ deficiency as a reliable thrombophilic risk biomarker in Egyptian patients with ACS.