IMPACT OF HIGH ON-TREATMENT PLATELET REACTIVITY ON 5-YEAR MORTALITY IN PATIENTS AFTER MYOCARDIAL INFARCTION

Background
High on-treatment platelet reactivity (HTPR) is expected to be a negative prognostic factor in patients with coronary artery disease. However, long-term results in patients with acute myocardial infarction are lacking.

Aims
The aim of the study was to assess the relationship between HTPR and five-year mortality in patients with acute myocardial infarction.

Methods
We performed a prospective cohort study of 198 patients with acute myocardial infarction. In these patients, the response to aspirin and clopidogrel was assessed by impedance aggregometry. According to their response to antiplatelet treatment, the patients were divided into groups with adequate response, dual poor responsiveness (DPR), poor responsiveness to aspirin (PRA) and poor responsiveness to clopidogrel (PRC). After five years, the myocardial infarction recurrence and overall mortality were assessed.

Results
Five-year mortality was significantly higher in all groups of patients with HTPR compared with patients with sufficient response to antiplatelet treatment: in PRA patients 38.1 % vs. 19.2 %, p <0.01, in PRC patients 45.2 % vs. 17.3 %, p<0.001 and in DPR patients 50.0 % vs. 19.9 %, p<0.05. Risk of repeated myocardial infarction was also increased (HR 4.0, 95 % CI 1.25-11.5, p<0.05 for DPR, HR 4.37, 95 % CI 1.51-12.77, p<0.01 for PRA, HR 3.25, 95 % CI 1.11-9.36, p<0.05 for PRC). In a multivariable analysis, HTPR and left ventricle systolic dysfunction were proven to be independent predictors of mortality.

Summary
PRA, PRA and DPR are independent predictors of increased five-year mortality and risk of repeated myocardial infarction.

Keyword(s): Mortality, Myocardial infarction, Platelet reactivity

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