Quantitative assessment of myocardial blood flow by dynamic single photon emission computed tomography: relationship with ECG changes and biochemical markers of damage in patients with acute myocardial infarction

Aim: To study the relationship of microcirculatory changes in coronary bed and electrocardiographic and laboratory signs of damage to myocardium in patients with acute myocardial infarction (AMI). Methods. The observational study included patients with newly emerged AMI. Depending on the ECG changes, the patients were divided into two groups: 1) with ST segment elevation (n = 75) (STEMI) and 2) without ST segment elevation (n = 44) (NSTEMI). All patients underwent electrocardiography, analysis of biochemical markers of myocardial damage, dynamic single photon emission computed tomography (SPECT) and myocardial perfusion imaging. Results. The study included 119 patients (age 62.5 ± 10.4 years, 63% men). STEMI patients had heavier perfusion defects at rest, 5.00 (3.00;9.00) and 0.00 (0.00;1.00), and after pharmacological stress test, 7.00 (5.00;13.00) and 2.50 (0.00;5.00), also they had more reduced stress myocardial blood flow (MBF), 1.09 (0.83;1.59) and 1.67 (1.36;2.46) ml/min/g, flow difference (FD), 0.36 (0.01;0.72) and 1.14 (0.63;1.72) ml/min/g, and myocardial flow reserve (MFR), 1.78 (1.11;2.19) and 2.57 (2.13;3.31), according to compared to NSTEMI patients. Correlation analysis revealed significant relationships between stress MBF and CPK after 24 hours and 4 days: r = –0.34 and r = = –0.31, troponin I upon admission and after 24 hours – r = –0.4 and r = –0.3; MFR and FD and troponin I upon admission – r = –0.41 and r = –0.41. Conclusion. Quantitative parameters of myocardial perfusion determined by early dynamic myocardial SPECT are associated with electrocardiographic changes and biochemical markers of myocardial damage and allow an adequate assessment of the severity of the disease in patients with AMI.