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 clear, however, 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 elevation 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.(ABSTRACT TRUNCATED AT 250 WORDS)