Prognostic value of isolated troponin I elevation after percutaneous coronary intervention.

BACKGROUND Mild elevations of cardiac troponin are frequent after percutaneous coronary intervention (PCI). Their prognostic value is uncertain in the absence of changes in creatine kinase-MB (CK-MB). METHODS AND RESULTS We evaluated the relation between isolated elevations of cardiac troponin I (cTnI) and all-cause mortality. We studied 3494 consecutive patients who underwent PCI in 16 Italian tertiary cardiology centers. CK-MB and cTnI were analyzed in a central laboratory. Duration of follow-up was 2 years. The present analysis was restricted to 2362 patients with normal CK-MB and cTnI values at baseline and no CK-MB elevation after PCI. A rise in cTnI after PCI >0.15 ng/mL, the upper reference limit, was found in 932 patients (39.4%). A rise >0.45 ng/mL (>3×upper reference limit) was found in 467 patients (19.7%). Compared with patients with normal cTnI, those with cTnI elevation >0.15 ng/mL showed a slightly increased mortality (3.8% versus 2.6%; hazard ratio, 1.53; 95% confidence interval, 0.97 to 2.42; P=0.069). A cTnI elevation >0.45 ng/mL was associated with a higher risk of mortality (4.5% versus 2.7%; hazard ratio, 1.68; 95% confidence interval, 1.01 to 2.80; P=0.044), which, however, did not remain significant after adjustment for concomitant risk factors (hazard ratio, 1.45; 95% confidence interval, 0.86 to 2.46; P=0.162). Postprocedural cTnI elevation was associated with coronary and clinical features consistent with a worse risk profile. CONCLUSIONS In the absence of a rise in CK-MB, elevated cTnI levels after PCI are associated with a modest increased risk of death. However, this is not independent of the concomitant adverse baseline clinical characteristics of these patients.