oa Time Course of Platelet Activation Markers as a Potential Prognostic Indicator after Primary Percutaneous Coronary Angioplasty in Qatar

Rationale

Myocardial infarction (MI) is one of the leading causes of death and disability worldwide. In Qatar specifically, cardiovascular diseases account for 20% of the main causes of death in the country, and the cases of MI is rising rapidly. Recent developments in the management of MI, particularly the emergent opening of the Culprit artery by primary percutaneous coronary intervention (PPCI), have resulted in significant improvement of outcome in patients. In spite of that, the early and long outcome following MI varies considerably in different patients, and a significant number develop major adverse cardiac events (MACE) in the first year after successful PPCI. The clinical complications of MI, such as ventricular remodelling and heart failure, are thrombo-inflammatory processes that involve platelet activation and interactions with blood cells, the endothelium, and the myocardium. Increased platelet activation has been reported in numerous cardiovascular diseases including hypertension, atherosclerosis, stroke, acute coronary syndromes, and myocardial infarction. However, the course of platelet activation after MI and its role in adverse remodelling has not yet been assessed.

Objective

The aim of this study is to evaluate the time course of platelet activation markers in patients diagnosed with acute ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI) in Qatar. Findings will be correlated with patients’ clinical outcomes to evaluate the role of platelet activation markers as prognostic markers of disease progression in adverse remodelling after PPCI.

Methods

Platelet activation was assessed by expression of inflammatory markers platelet P-selectin (CD62P), and lysosome-associated membrane protein (CD63), and formation of platelet-neutrophil aggregates (PNA) using flow cytometry. Measurements were done in peripheral blood samples obtained from healthy subjects (n = 25) and from patients at admission to the cath lab at day 0 (n = 55) before PPCI, and 48 hours (n = 51) and, 1 month (n = 48) after PPCI. P-selectin and CD63 expression is defined as the percentage of antibody-positive platelets (P-sel+ and CD63+). PNA are gated by their characteristic forward and side scatter properties and identified as dual-labelled cells in the gate of neutrophils exhibiting leukocyte CD45 and platelet CD42b fluorescence (CD45+/CD42b+).

Results

Platelet P-selectin and CD63 expression were high in patients at day 0 than in healthy control subjects (% of expression: 24.4 ± 3.0 vs 9.0 ± 2.7; p