Prognostic value of creatine kinase-myocardial band isoenzyme elevation following percutaneous coronary intervention: A meta-analysis

Objectives To assess whether different degrees of creatine kinase-myocardial band isoenzyme (CK-MB) elevation after percutaneous coronary intervention (PCI) affect the subsequent risk of death. Background While there is consensus that extensive cardiac enzyme elevation increase mortality significantly, there is uncertainty about the exact clinical impact of smaller CK-MB elevations after PCI. Methods The published literature was scanned by formal searches of electronic databases such as PubMed and MEDLINE from January 1999 to October 2011. Risk ratio (RR) was used as summary estimate. Results Ten studies have been included totaling 48,022 patients who underwent PCI (12,246 patients with CK-MB elevation and 35,776 patients without CK-MB elevation). Mean followup duration for each study ranged from 6 to 48 months. CK-MB elevation >1× the upper limit of normal (ULN) conferred a significant increase in the risk of mortality with an overall RR of 1.74 (95% confidence interval [CI], 1.42 to 2.13, P < 0.001). Compared with patients without CK-MB elevation, there was a dose-response relationship with RR for death being 1.48 (95% CI, 1.25-1.77, P < 0.001) with CK-MB elevation 1 to <3× ULN, 1.71 (95% CI, 1.23-2.37, P = 0.001) with CK-MB elevation 3 to 5× ULN, and 2.83 (95% CI, 1.98-4.04, P < 0.001) with CK-MB elevation ≥ 5× ULN. Conclusions Even a small increase in CK-MB levels after PCI is associated with significantly higher risk of late mortality. Monitoring cardiac enzymes after PCI may help predict the long term clinical outcome.