In the last 10 years a large number of studies have clearly shown that mild-to-moderate elevations of biochemical markers of myocardial damage are frequently detected after percutaneous coronary revascularization, but the clinical significance of these findings is still debated. Side branch occlusion, abrupt vessel closure and major dissection are the factors most frequently responsible for myocardial damage after stent implantation. However even in the case of a successful and uncomplicated procedure, enzyme leak may occur as a result of coronary microembolization. Post-procedural creatine kinase (CK)-MB rise is detected in 10 to 20% of the cases and is associated with a higher risk of death; the level of risk seems to increase linearly with any elevation of the marker, with no obvious threshold effect or cut-off value. Post-procedural elevations of cardiac troponins, occurring in almost 50% of the cases, do not seem to predict long-term mortality and do not add any prognostic information to that offered by CK-MB. Potential mechanisms responsible for adverse prognosis after CK-MB elevation include increased susceptibility to ventricular arrhythmias via microreentrant circuits, compromise of coronary collaterals, and microvascular circulation dysfunction. Although a cause-and-effect relationship between CK-MB elevation and adverse outcome has not been clearly demonstrated, post-procedural myonecrosis should be prevented, systematically sought for and, if detected, always reported in order to define the patient's risk profile more precisely.