Cardiac troponins are sensitive and specific markers for the detection of minor myocardial injury. However, they have been rarely used to monitor myocardial injury after coronary stenting. The purpose of the study was to measure cardiac troponin I (cTnI) and cardiac troponin T (cTnT) levels after elective uncomplicated successful percutaneous transluminal coronary angioplasty (PTCA) with or without coronary stenting and to compare their results with serum creatinine kinase MB isoenzyme (CKMB). CTnI and cTnT levels were compared with those of CK or CKMB in 98 consecutive patients with stable angina undergoing elective uncomplicated successful PTCA with stenting (n = 71) or without stenting (n = 27). Markers were measured before and 6, 12, 24, and 48 hr after the procedure. Peak postprocedural levels for each marker were compared and related to angiographic and procedural characteristics as well as to the occurrence of side-branch occlusion. None of the patients had abnormal markers before the procedure. Abnormal postprocedural values of one or more markers were observed in 28 patients (29%), 23 after stenting and 5 after PTCA alone. The frequencies of abnormal cTnI and cTnT levels were significantly higher than that of CKMB after coronary intervention (26% and 18% vs. 7%; P = 0.00016 and 0.015, respectively), with cTnI being the most significant. When compared with troponin-negative patients, abnormal cardiac troponin values were significantly related to total time of inflation (223 +/- 128 vs. 170 +/- 105 sec; P = 0.008) and inflation maximal pressure (12.9 +/- 2.3 vs. 12.0 +/- 2.7 atm; P = 0.04). Small side-branch occlusion was noticed in 36% of the troponin-positive patients and in 6% of the troponin-negative group (P = 0.00047). In conclusion, minor myocardial injury is not uncommon after elective uncomplicated successful PTCA with or without stenting. Cardiac troponins, especially cTnI, are more sensitive than CKMB for the detection of this minor myocardial injury. Total time of inflation and inflation maximal pressure are predictors of postprocedural elevation of cardiac troponins. Side-branch occlusion may account for some, but not all, periprocedural minor myocardial injury.