Aims: The optimal cut-off value of isolated cardiac biomarker elevation for defining prognostically important percutaneous coronary intervention (PCI)-related myocardial injury is not known. We performed a meta-analysis to evaluate the dose-response relationship between isolated cardiac biomarker elevations and the risk of all-cause mortality following elective PCI.
Methods and results: Twenty-four prospective studies (44,972 patients) were included. Patients with an isolated elevation of cardiac biomarkers had an increased risk of all-cause mortality when compared to those with no elevations (cardiac troponin I: odds ratio [OR] 1.42, 95% confidence interval [CI]: 1.19-1.69; creatine kinase-MB isoenzyme [CK-MB]: OR 1.43, 95% CI: 1.19-1.70). For the dose-response analysis, elevations of cardiac troponin I >3x or CK-MB >1x the 99th percentile upper reference limit (URL) were associated with increased mortality (cardiac troponin I: OR 1.51, 95% CI: 1.05-2.17; CK-MB: OR 1.25, 95% CI: 1.05-1.48). The pooled OR of mortality for each 3xURL increment of cardiac troponin I or CK-MB was 1.33 (95% CI: 1.15-1.53) and 1.38 (95% CI: 1.30-1.47).
Conclusions: We found that a positive dose-response relationship between isolated cardiac troponin I and CK-MB with all-cause mortality and elevated cardiac troponin I >3x or CK-MB >1x the 99th percentile URL was associated with an increased risk of mortality.