Higher incidence and serum levels of minor cardiac biomarker elevation in sirolimus-eluting stent (Cypher) than bare metal stent implantations

OBJECTIVES: Minor cardiac biomarker elevation after percutaneous coronary intervention has long-term prognostic significance. The sirolimus-eluting stent (Cypher) has been reported to require high postinflation pressure for optimal implantation. We examined the incidence of minor cardiac biomarker elevation induced by Cypher implantation. METHODS: We measured the serum concentration of cardiac troponin-I (cTnI) 24 h after stenting and those of creatine kinase isoenzyme MB and creatine kinase before, immediately after, and 6, 12 and 24 h after implantation in patients who underwent Cypher stent (CS group; n=53) or bare metal stent (BMS group; n=57) implantation. RESULTS: No significant difference in clinical background was observed between the two groups. When a cutoff cTnI value of 0.50 ng/ml was used, the CS group showed a significantly higher incidence of cTnI elevation (35.8%, 19/53) than the BMS group (14.0%, 8/57) (P<0.05). Similarly, the incidence of cTnI 0.03 ng/ml tended to be higher in the CS group (88.7%, 47/53) than in the BMS group (73.7%, 42/57: 0.05<P<0.10). Furthermore, the CS group showed significantly higher cTnI levels than the BMS group (1.32±2.38 vs. 0.34±0.91 ng/ml. P<0.001). Essentially, similar results were obtained for serum creatine kinase isoenzyme MB and creatine kinase. Among clinical, lesion and procedural characteristics, postinflation pressure for stenting was significantly higher only in the CS group (18.2±2.8 atm) than in the BMS group (14.0±2.7 atm) (P<0.001). CONCLUSIONS: The results demonstrated that CS implantation increases the incidence of minor cardiac biomarker elevation compared with BMS. The difference in postinflation pressure could account for the results.