Abstract 4166: Association of Residual Platelet Reactivity After Clopidogrel Loading With Intracoronary Thrombus Burden and Myocardial Necrosis After Coronary Intervention, in Patients With Acute Myocardial Infarction
Objectives: We investigated whether the angiographically detected intracoronary thrombus burden is affected by residual platelet reactivity after clopidogrel loading in patient with acute myocardial infarction (AMI). In addition, we hypothesized that residual platelet reactivity may influence myocardial perfusion after percutaneous coronary intervention (PCI).
Background: Residual platelet reactivity, measured by a point-of-care assay, was shown to predict 12-month cardiovascular death and nonfatal myocardial infarction in patients with acute coronary syndromes. Possible pathophysiological mechanisms have been proposed but not clearly defined, yet.
Methods: A total of 61 consecutive patients, presented with AMI, were finally enrolled. We used the VerifyNow P2Y12 assay (Accumetrics Inc, San Diego, Calif) to determine residual platelet reactivity after clopidogrel loading, expressed in P2Y12 Reaction Units (PRU). Intracoronary thrombus burden was angiographically estimated and categorized as large thrombus burden (LTB), defined as thrombus burden ≥2 vessel diameters, and small thrombus burden (STB). Thrombolysis in Myocardial Infarction (TIMI) flow and Myocardial Blush (MB) were also estimated and categorized after PCI in two groups of normal and impaired TIMI and MB levels.
Results: Clopidogrel “resistance” levels were found to be significantly higher in LTB group compared to STB group (284.4±91.4 vs 217.2±90.8 respectively, p=0.004). Impaired TIMI flow and MB after PCI, were significantly associated with higher PRU levels (p=0.001 and p=0.004, respectively). Finally, PRU levels was significantly related with maximum creatine kinase-MB (CK-MB) levels (r=0.324, p=0.034) during hospitalization. The aforementioned results remained statistically significant among the subgroup of STEMI patients.
Conclusions: Patients with AMI and larger coronary thrombus burden had higher PRU levels. Impairedpost-PCI TIMI flow and MB, as well as higher CK-MB levels were associated with increased PRU levels.