The limited value of dipyridamole stress myocardial perfusion SPECT for detecting jeopardized myocardium early after AMI.

초록

Objectives: We investigated the value of dipyridamole stress myocardial perfusion SPECT (Dip SPECT) in identifying patients for postinfarct ischemia (jeopardized myocardium) within the infarct region early after AMI. Methods: Fifty-five patients (M/F=39/16, 58±13 years) with an uncomplicated AMI (anterior: 32, inferior: 23 patients) underwent Dip SPECT and coronary angiography (CAG). Sixteen patients received thrombolytic therapy. In the acute phase (mean 3±1 days post infarction), rest 201Tl and dipyridamole stress 99mTc MIBI SPECT were performed. The segmental perfusion was graded semiquantitatively using a 4 point scoring method from normal (0) to absent uptake (3). A reversible perfusion defect was defined as if the score at rest in two adjacent infarct-related segments was at least one grade lower than on the dip images. CAG was performed the next day after Dip SPECT. Significant coronary artery disease was defined as a diameter stenosis≥70% in ≥1 major epicardial artery. The peri-infarct zone was defined as myocardial segments in the distribution of the infarct-related artery(IRA). Results: Among 55 patients, 45 had a significant stenosis of IRA. In 10 patients, IRA was not signifcantly narrowed (LAD: 8, RCA: 2). A reversible perfusion defect within the infarct region was observed in 39 of the 45 patients with a significant stenosis of IRA (sensitivity 87%) and 9 of the 10 patients without a significant stenosis of IRA (specificity 10%). Conclusion: The very low specificity of Dip SPECT is limitation for detecting jeopardized myocardium within infarct region early after AMI. And it was mainly related to the impaired coronary flow reserve after recanalization.