Nuclear imaging techniques in the assessment of myocardial perfusion and function after CABG: does it correlate with CK-MB elevation?

BACKGROUND An increase of the creatine kinase MB (CK-MB) isoenzyme after cardiac surgery suggests perioperative myocardial infarction. The interpretation is more difficult when increased enzymes are not accompanied by electrocardiographic markers of infarction. The aim of this study was to correlate the results of myocardial perfusion imaging (MPI) and radionuclide ventriculography (RNV) with CK-MB isoenzyme level in patients without ECG abnormalities after CABG. MATERIAL AND METHODS 36 patients (age: 52.5 +/- 8.5 years, 33M/3F) treated with CABG were prospectively studied. CK-MB level was assessed at 0, 4, 8, 12, 24, 36, 48 and 72 hours after surgery. MPI (SPECT using Tc-99m-MIBI) and RNV were performed 2 weeks before and 3-4 months after surgery. All patients had an uneventful hospitalisation. The subjects were divided into two groups: group 1 with CK-MB increase > 50 IU/ml (n = 9) and group 2 with CK-MB levels 50 IU/ml) after coronary artery surgery have a higher rate of perfusion and function deterioration. The increase of CK-MB level early after coronary bypass surgery in patients without ECG markers of perioperative infarction indicates a probable ischaemic insult during surgery.