Abstract 10045: A Novel Approach to Define Type 4a Myocardial Infarction in Acute Coronary Syndrome Patients Undergoing Early Invasive Management: Insights From the CHAMPION PLATFORM Trial
Background: Early PCI in pts with nSTE-ACS challenges the diagnosis of PCI-related MI. In CHAMPION PLATFORM, PCI was performed a median of 7.9 hours after admission, which may have hindered sensitivity in detecting efficacy of cangrelor. The Universal definition of MI defines PCI-MI (type 4a MI) at >3x upper limit of normal (ULN) only if biomarkers are stable/falling pre-PCI and also recommends reporting biomarker elevations as 5x and 10xULN.
Methods: Using a method based on CK-MB trend evaluation to identify type 4a MI, we re-classified PCI-MI in PLATFORM to reflect Universal MI definition. We also re-assessed randomized treatment effect using re-classified MI and compared with the original clinical events committee (CEC) adjudication results, which was based on timing of symptoms, procedures, and MB data but did not strictly require stable or falling CK-MB pre-PCI. Plots of CKMB values in relationship to time of randomization and PCI were created for all pts. Two blinded physicians independently reviewed every plot. Type 4a MIs were identified only in pts with normal or stable/falling biomarkers (primary cohort) and compared with original CEC adjudicated endpoints.
Results: Among 5,295 pts in the modified intention to treat population, plots review identified 3,410 (64.4%) pts in the primary cohort. In the remainder, CKMB were ascending prior to PCI and type 4a MI could not be assessed. The rate of type 4a MI was 4.3% (CKMB >3xULN) (227 events) while the original CEC PCI-MI rate was 6.5% (344 events). Randomized treatment effects on PCI-MI and on the composite primary endpoint are shown (Figure).
Conclusions: Using the Universal MI Definition, Type 4a MI was less common than the original, CEC-defined PCI-MI, as over 1/3 of pts had ascending pre-PCI CKMB values. The Universal MI definition may enhance specificity for the diagnosis of PCI-MI and suggests more favorable treatment effect for cangrelor. This hypothesis is being tested in PHOENIX, a large, ongoing phase III trial
- © 2011 by American Heart Association, Inc.