Role of myocardial perfusion scintigraphy post invasive coronary angiography in patients with Myocardial Infarction

BACKGROUND: The presence of severe hypokinesia or akinesia and near complete stenotic lesions on coronary angiography, in a patient with acute myocardial infarction raises a question of viability in the involved territory and its response to revascularization. The decision of revascularization can be effectively taken after myocardial perfusion scintigraphy (MPS). AIM: To evaluate the role of MPS in patients with acute or recent myocardial infarction after invasive coronary angiography. MATERIALS AND METHODS: Thirty-five patients (27 Males, 8 Females; Mean age 54 years) with acute myocardial infarction, who underwent invasive angiography, were included prospectively. Invasive angiography was attempted during the episode of acute chest pain in 20 patients. Fifteen patients underwent angiography without MPS because of non-availability of MPS at the time of initial presentation in the referring hospital. Revascularization was deferred because of complete / near complete block of artery with hypokinesia / akinesia of the distal LV segments in 32 / 35 patients and 50 to 70% block in 3 / 35. These patients were subjected to MPS. RESULTS: Twenty patients underwent stress MPS and 15 underwent nitrate-augmented rest re-distribution study (RR study). Imaging was performed using the hybrid SPECT / CT system. The average defect size of the perfusion defect was 34% (5 - 57% range). Sixteen patients (46%) had fixed perfusion defects. Reversible ischemia was present in 19 (54%). Ten patients had a < 10% reversible perfusion defect. Nine patients had reversible ischemia, > 10% of the LV myocardium, and underwent the invasive revascularization procedure. CONCLUSION: MPS is invaluable in patients who have total / near total occlusion of the coronary artery and distal segment hypokinesia or akinesia on invasive angiography. One in four patients, deemed to have non-viable myocardium, underwent an invasive revascularization after undergoing MPS.