Biochemical detection of minor myocardial injury after elective, uncomplicated, successful percutaneous coronary intervention in patients with stable angina: clinical outcome.

BACKGROUND: Minor elevations of creatine kinase MB isoform (CK-MB) identified a population with a worse long-term prognosis after successful coronary intervention. Recent studies provide evidence that cardiac troponin I (cTnI) is more sensitive than CK-MB for the detection of minor myocardial injury after coronary intervention. The purpose of the study was to determine the prognostic value of cTnI elevation after elective uncomplicated successful percutaneous coronary intervention (PCI).

METHODS: cTnI was measured in 96 patients with stable angina before and 24 h after elective uncomplicated successful percutaneous transluminal coronary angioplasty (PTCA) with or without stenting. Patients were followed up for adverse cardiac events (recurrent angina, non-fatal myocardial infarction, cardiac death, repeat PCI or coronary bypass surgery). Procedure success was achieved in all cases.

RESULTS: Cardiac events were best predicted by cTnI when a cut-off value of 2.0 microg/L was used. Abnormal cTnI values at 24 h after PCI were observed in 26 patients (27%). Over a follow-up period of 24 months with no significant difference in the medication used, the incidence of recurrent angina, repeat PCI, coronary bypass surgery and cardiac death was 54%, 46%, 4% and 4%, respectively, in the cTnI-positive patients versus 27%, 16%, 4% and 0% in the cTnI-negative patients. Kaplan-Meier survival analysis showed that cTnI elevation was a significant correlate of cardiac events (P = 0.0198, by log rank analysis).

CONCLUSIONS: Elevation of cTnI is not uncommon after elective uncomplicated successful PCI in patients with stable angina and this elevation might be a marker of adverse long-term outcome.