Occurrence of non-Q wave myocardial infarction following percutaneous coronary intervention in the stent era: systematic monitoring of the three markers of myocardial necrosis.

OBJECTIVES: To compare the elevation of the three markers total creatine kinase (CK), CK-MB mass, and troponin I (TnI) and their relationship with clinical and procedural characteristics following percutaneous coronary intervention (PCI).

METHODS: We prospectively evaluated 385 patients consecutively undergoing successful PCI. The three markers were systematically measured before and at 6, 12, and 24 hours after PCI. Any increase above the upper normal limit (UNL) of any marker has been considered abnormal when basal values were normal, while a further increase was needed when basal values were altered. Patients with ongoing acute myocardial infarction were excluded from the analysis.

RESULTS: TnI was above UNL in 183 patients (51%); in 138 (38.5%) it was the only marker altered. CK-MB mass was elevated in 12.8% patients, more than 3x UNL in 5.5% and more than 5x UNL in 2.8%. In over one half of these patients, CK-MB values peaked at 12 hours following PCI. Total CK was above UNL in 23 patients only (6.4%) and more than twice UNL in 5 (1.4%). Only 1 patient out of the 5 with CK-MB mass more than 10x UNL had total CK higher than twice UNL. In our population, post-PCI elevation of myocardial necrosis markers correlate with the occurrence of minor procedural complications (observed overall in 7.8% cases; TnI and/or CK-MB > 1xUNL 96% vs 47.5%, P < 0.001) and the presence of higher complexity clinical and/or procedural features, such as multivessel disease, multivessel or multilesion PCI, multiple stenting and use of glycoprotein IIb/IIIa inhibitors.

CONCLUSIONS: The elevation of at least one biochemical marker of myocardial necrosis is frequent following successful PCI with routine stent implantation. CK-MB mass is the most practical marker, having optimal kinetic and peaking with the first 12-18 hours post-PCI. Definitive data on the prognostic role and the applicability for the diagnosis of myocardial infarction of minor elevation of CK-MB mass or isolated increase of TnI are lacking.