Introduction: Myocardial reperfusion during the course of an acute myocardial infarction improves patients' short- and long-term prognosis; coronary blood flow is successfully re-established while preserving a large amount of at-risk muscle. Clinical evolution, however, varies. Presence of residual ischemia or viable myocardial tissue affects a patient's prognosis. Assessment by noninvasive methods allows better prognostic stratification. Cardiac-gated SPECT provides appropriate parameters to support treatment selection and monitoring of these patients.
Objectives: Assess the prognostic value--ability to predict occurrence of major cardiac events--of perfusion and cardiac function obtained by myocardial perfusion scintigraphy in myocardial infarction patients treated by any myocardial reperfusion method, whether pharmacological or surgical.
Methods: Forty patients were included, mean age 58.8 ± 9 years, diagnosed with myocardial infarction. Participants were divided into two groups: primary percutaneous transluminal coronary angioplasty (15) or thrombolysis (25). All received myocardial perfusion scintigraphy with cardiac-gated SPECT to assess perfusion and left ventricular function, and were followed for six months with telephone interviews and review of clinical records.
Results: In the 11 patients who had major cardiac events within six months of followup, a nonsignificant increase in perfusion defect extent was seen post reperfusion. Six (54.5%) of those with major cardiac events had anterior perfusion defects. In functional parameters, a significant increase in end-diastolic and end-systolic volumes and decrease in left ventricular ejection fraction were observed post stress (p = 0.006) and at rest (p = 0.001). Post-stress end-diastolic volume of ≥70 mL had a higher prognostic value for major cardiac events [sensitivity 100%; specificity 89%, area under ROC curve 0.835 (CI 0.702-0.969), p = 0.001].
Conclusions: Cardiac-gated SPECT is useful to identify variables (including left ventricular systolic dysfunction and dilation of left cavities, particularly left end-systolic volume of >70 mL) predictive of major cardiac events in reperfused patients, independent of treatment modality.