Abstract 14680: Correlation Between Intracoronary Thrombus Burden And Residual Platelet Inhibition After Clopidogrel Loading in Patients With ST-Elevation Myocardial Infarction Undergoing Unexpectedly-Delayed Primary Percutaneous Coronary Intervention
Background: Residual Platelet Reactivity (RPR) after clopidogrel loading, measured by the VerifyNow assay, has been shown to predict 12-month clinical events in patients with acute coronary syndromes. However, links between coronary angiographic findings and outcome in patients with ST-elevation myocardial infarction (STEMI), with RPR have not been reported. We investigated whether RPR is associated with the amount of intracoronary thrombus burden (TB) in patients with STEMI undergoing unexpectedly-delayed primary percutaneous coronary intervention (pPCI). Moreover, we evaluated whether RPR may influence coronary flow and myocardial perfusion immediately post-pPCI.
Methods and Results: VerifyNow assay was used to determine RPR after clopidogrel loading, expressed in P2Y12-Reaction-Units (PRU). Intracoronary-TB was angiographically estimated and stratified as TB-Grade-A, -B and -C. Thrombolysis in Myocardial Infarction (TIMI) flow and Myocardial Blush (MB) were also estimated post-PCI. A total of 74 consecutive patients, presented with STEMI, were enrolled in the study. Patients with greater TB presented significantly higher PRU-levels (174.1±91.5, 196.23±113.4 and 252.8±107.8 for TB-Grade A, B and C, respectively; p=0.044). PRU-levels >251.5 were shown to predict Large-TB (LTB; TB-Grade-C) (sensitivity=57.9%; specificity=77.8%; p=0.014). This association remained significant (p=0.002) after adjustment for various demographic and clinical characteristics. Impaired TIMI-flow and MB after PCI were significantly associated with higher PRU-levels (p<0.001).
Conclusions: Among the studied patients those with higher RPR, after clopidogrel loading, presented larger intracoronary thrombus burden, worse post-PCI myocardial flow and perfusion.
- © 2011 by American Heart Association, Inc.