Differential mortality risk of postprocedural creatine kinase-MB elevation following successful versus unsuccessful stent procedures.

OBJECTIVES: This study was designed to evaluate the effect of periprocedural myocardial infarction (MI) on mortality according to success of the stent procedure.
BACKGROUND: The mortality effect of periprocedural MI relative to successful versus unsuccessful procedures has not been examined.
METHODS: All-cause mortality during the first year was evaluated prospectively among 5,850 patients from coronary stent clinical trials. Myocardial infarction was classified according to creatine kinase-MB level as type 1 (>1 but <3 times normal), type 2 (>or=3 but <or=8 times normal), or type 3 (>8 times normal or Q-wave MI). Procedures were classified as successful unless there was a final diameter stenosis >50%; final Thrombolysis In Myocardial Infarction flow grade <3; final National Heart, Lung, and Blood Institute dissection grade >or=D; repeat revascularization within 24 h; or stent thrombosis within 24 h.
RESULTS: Myocardial infarction was more frequent after unsuccessful procedures (69.6% vs. 20.4%, p < 0.001). Mortality during the first year was higher in patients with MI (2.8% vs. 1.7%, p = 0.01), but the effect was significant only for type 3 MI (4.7% vs. 1.7%, p = 0.008). Moreover, the mortality difference for any MI was confined to patients with unsuccessful procedures (13.1% vs. 0%, p = 0.03), with no significant effect among patients with otherwise successful procedures (2.1% vs. 1.7%, p > 0.20). The independent predictors of mortality were unsuccessful procedure (p < 0.001), diabetes mellitus (p = 0.001), history of prior MI (p = 0.003), multivessel disease (p = 0.006), and advancing age (p < 0.001), but not periprocedural MI.
CONCLUSIONS: The association of periprocedural MI with increased mortality during the first year following stent placement was confined to patients with unsuccessful procedures.