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 2·0μg/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.
