ELEVATION OF THE CREATINE-KINASE MYOCARDIAL ISOFORM FOLLOWING OTHERWISE SUCCESSFUL DIRECTIONAL CORONARY ATHERECTOMY AND STENTING

Moderate elevation of creatine kinase (CK) MB isoform is common following otherwise successful percutaneous coronary revascularization, and is frequently interpreted as evidence of a non-Q-wave myocardial infarction. It is not dear, howev er, whether elevation of CK MB isoform carries sufficient adverse clinical impact to be categorized as a ''major'' complication. We therefore explored the incidence and clinical consequence of elevation of CK MB isoform in a consecutive series of 565 patients who had otherwise successful directional coronary atherectomy (n = 274) or stenting (n = 291), and were followed for a mean, of 2 years. Of this cohort, 11.5% had postprocedure elevation of the CK MB isoform above normal (10 IU/liter). These patients tended to be older and to have undergone atherectomy of a de novo lesion with adverse morphology (thrombus, calcification, eccentricity). Patients with elevation of CK MB isoform following otherwise successful revascularization generally showed no adverse long-term sequelae (death, recurrent myocardial infarction, repeat revascularization) compared with patients without eleva tion of CK MB isoform. Only 2.3% of the patients who had CK MB isoform release >50 IU/liter demonstrated a trend (p = 0.08) toward decreased late survival, compared with patients without CK MB isoform elevation. While minor CK MB isoform elevation is common (11.5%) after successful coronary stenting or directional atherectomy, it generally has no adverse clinical consequences, and should not be considered a major complication. Greater CK MB isoform elevations (>50 IU/liter) are less common (2.3%), but appear to adversely affect long-term clinical outcome and should thus probably be considered along with Q-wave myocardial infarction as a major complication in reporting new device results.