Abstract 16865: Long-Term Clinical Outcomes of Patients with Type 4a Myocardial Infarction Following Elective PCI for Stable Ischemic Heart Disease (SIHD): Post Hoc Analysis of the COURAGE Trial
Background: The relevance of peri-PCI (type 4a) myocardial infarction (MI) is controversial, as is the type of biomarker (CK-MB or troponin) and threshold (e.g., 3x or 5x ULN; other?) used to determine prognostically-important clinical events. While the current 2007 Universal MI Definition designates a biomarker (CK-MB or troponin) elevation >3x the 99th percentile URL as a type 4a MI, data from recent PCI trials have failed to show a significant independent association between peri-PCI MI and mortality up to 2 years using this definition. Whether type 4a MI is associated with mortality or subsequent type 1 MI during longer-term follow-up is unknown.
Methods: We performed a post hoc analysis of clinical outcomes (all-cause mortality, spontaneous [type 1] MI, or hospitalization for acute coronary syndrome [ACS]) among 1,371 SIHD patients (pts) from the COURAGE Trial who underwent initial PCI and long-term (2.5-7.0 year [mean 4.6 year]) follow-up. All pts had ≥70% stenosis in at least one major coronary artery that met an AHA/ACC Joint Task Force Class I-II indication for PCI. Type 4a MI was defined as CK-MB ≥ 3x ULN or troponin ≥ 5x ULN plus angina or an angina equivalent within 24 hours post-PCI; type 1 MI was defined as new ECG Q-waves or CK-MB ≥ 1.5X ULN or troponin ≥ 2x ULN plus angina/new ischemia equivalent.
Results: Protocol-defined type 4a MI occurred in only 51 pts (4%). The rate of subsequent all-cause mortality was low and occurred in 6% of patients who had peri-PCI MI (3/51) and in 8% of pts without peri-PCI MI (99/1,320); P=NS. However, pts who sustained an initial type 4a MI had significantly higher rates of subsequent non-fatal events with 16/51 pts (31%) developing a subsequent type 1 MI and 17/51 pts (33%) requiring hospitalization for ACS, as compared with a type 1 MI rate of 9% (118/1,320) and ACS hospitalization rate of 11% (148/1,320 pts) in those without an initial peri-procedural MI (P <0.0001 [Fisher-Exact Test] for type 1 MI and ACS.
Conclusions: Type 4a peri-PCI MI, as defined above, was associated with an increased rate of type 1 MI and re-hospitalization for ACS during a mean 4.6 year follow-up, the significance of which may be prognostically-important. However, long-term mortality remained low regardless of the presence or absence of initial type 4a MI.
- © 2012 by American Heart Association, Inc.