Troponin I and Creatine Kinase MB do not provide comparable information after PCI

Objectives. To compare cardiac troponin I (cTnI) and creatine kinase-MB (CK-MB) after PCI in cases with normal baseline levels of both biomarkers. Design. cTnI and CK-MB after PCI were stratified as multiples of the 99<SUth</SU percent upper reference limit (99%URL) and compared to each other in 489 patients. Post-PCI levels > three times 99%URL were classified as procedure-related infarctions. Results. After PCI, CK-MB was > 3x99%URL in 58/486 patients (12%) and cTnI > 3x99%URL in 292/487 patients (60%). cTnI was > 10x99%URL in all cases with infarction according to CK-MB but CK-MB was often normal despite elevated cTnI. There was an only minimal overlap between two infarction populations, those with cTnI in the range from 1x to 10x99%URL and those with CK-MB 1x to 10x99%URL. Conclusions. With the present quantification scales, infarction rate after PCI is > five-fold higher with cTnI than with CK-MB.