Background: Troponin I concentrations are frequently elevated following percut aneous coronary intervention(PCI) even in procedures without complications and a re considered, by some, as predictive of long term morbidity and mortality. We assessed whether post PCI troponin I concentrations bore any relationship to cl inical, angiographic and in laboratory minor adverse events indicative of myoca rdial injury and evaluated, in follow up, whether these levels are useful as a predictive markers of adverse events. Methods: Patients(n=147) who were schedule d for PCI for stent placement were prospectively studied. In laboratory events recorded were protracted chest pain, electrocardiographic changes, slow flows, d issections and lateral branch affectation. Troponin I and creatinine kinase MB f raction (CK MB) mass were measured at baseline and postprocedure. Mean clinical follow up was for 10.4±3.6 months. Results: During PCI, at least one adverse event occurred in 34%of patients and, in 38%of them, there was an elevation of troponin I as compared to 5.1%of those patients without any adverse event (rel ative risk=7.4; P< 0.001). Elevation of troponin I concentrations occurred in 16 .3%of all patients, 79.2%associated with an AE. CK MB was elevated in 15.6%o f patients. On multivariate analysis, protracted chest pain, lateral branch invo lvement and slow flow remained statistically significant in relation to post pr ocedure elevations of troponin I concentrations. Clinical follow up showed a po orer prognosis in patients who had had elevated troponin I concentrations. Concl usions: In laboratory adverse event predict elevated postprocedure troponin I c oncentrations which are associated with myocardial injury. These elevations, in turn, predict poorer medium term clinical outcomes. Background: Troponin I concentrations are following elevated percutaneous coronary intervention (PCI) even in procedures without complications and a re considered, by some, as predictive of long term morbidity and mortality. We assessed whether post PCI troponin I concentrations bore any relationship to cl inical, angiographic and in laboratory minor adverse events indicative of myoca rdial injury and evaluated, in follow up, whether these levels are useful as a predictive markers of adverse events. Methods: Patients (n = 147) who were schedule d for PCI for In laboratory events recorded were protracted chest pain, electrocardiographic changes, slow flows, d issections and lateral branch affectation. Troponin I and creatinine kinase MB f raction (CK MB) mass were measured at baseline and postprocedure. Mean clinical follow up was 10.4 ± 3.6 months. Results: During PCI, at least one adverse event occurred in 34% of patients and, in 3 8% of them, there was an elevation of troponin I as compared to 5.1% of those patients without any adverse event (rel ative risk = 7.4; P <0.001). Elevation of troponin I in the amount of 16.3% of all patients , 79.2% associated with an AE. CK MB was elevated in 15.6% of patients. On multivariate analysis, protracted chest pain, lateral branch invo lvement and slow flow in substantially significant significant relation to post pr ocedure elevations of troponin I concentrations. Clinical follow Up showed a po orer prognosis in patients who had elevated troponin I concentrations. These factors account for elevated postprocedure troponin I c oncentrations which are associated with myocardial injury. These elevations, in turn, predict poorer medium term clinical outcomes.