High prevalence of (99m)tc-tetrofosmin reverse perfusion pattern in patients with myocardial infarction and angiographically smooth coronary arteries

Background: There are no published data in the literature on the scintigraphic perfusion pattern in patients with myocardial infarction (MI) and normal coronary arteries (NCA). Objectives: To evaluate myocardial perfusion imaging in a series of patients with MI and NCA. Methods: Twenty-seven patients who had developed a MI and had NCA were studied. As a control group we included 27 patients with a recent MI and coronary artery disease (CAD). All patients underwent stress/rest tetrofosmin myocardial perfusion SPECT within 6 months from MI. Results: In patients with NCA tetrofosmin stress images revealed 41 hypoperfused segments in 17 patients (63%). On rest images, 13 segments remained unchanged, 4 showed partial reperfusion, 10 normalized and 14 worsened. Additionally, there were 18 new hypoperfused segments in nine patients. Therefore, perfusion worsened at rest in 18 patients (67%) (32 segments). Overall, at rest there were 49 hypoperfused segments in 22 patients (81%). In patients with CAD, stress images revealed 71 hypoperfused segments. On rest images, 39 segments remained unchanged, 16 showed partial reperfusion and 12 normalized. Four segments worsened at rest and only four patients (15%) showed new perfusion defects at rest. Conclusions: Myocardial perfusion with tetrofosmin might appear considerably worse at rest than at stress in patients with MI and NCA. Specifically, a reverse perfusion pattern in the infarct area is a frequent finding and is likely to be due to residual tissue viability. We postulate that in these patients the hyperemic response to exercise may mask resting underperfusion areas.