Prognostic value of normal exercise 99mTc-MIBI myocardial perfusion SPECT: comparison with exercise electrocardiography and coronary angiography

Myocardial perfusion scintigraphy is a useful technique to diagnose and to predict prognosis in patients with suspected or known coronary artery disease. The purpose of the present study is to evaluate the prognostic value of normal exercise 99mTc-MIBI myocardial perfusion single photon emission computed tomography (SPECT) and to analyze results with regard to those of exercise electrocardiography or coronary angiography. We evaluated 301 patients (mean age 52±10 years, 166 males and 135 females) with normal exercise 99mTc-MIBI myocardial perfusion SPECT performed for suspected coronary artery disease. Subjects were evaluated for cardiac events and followed for 8-55 months (mean 19±10 months) after imaging. During the follow-up period, there was no cardiac death but only one non-fatal myocardial infarction (event rate 0.21% per year). In addition, only one patient underwent coronary revascularization. There was no significant difference in cardiac event rate between patinets with positive (n=3D27) and negative (n=3D235) exercise electrocardiography (p:NS). There was no cardiac event in 17 patients who underwent coronary angiography (4 patients with >50% luminal narrowing, 2 patients with vasospasm and 11 patients with no significant lesion). Patients with normal exercise 99mTc-MIBI myocardial perfusion SPECT has a very low risk for cardiac events regardless of exercise electrocardiographic and coronary angiographic findings.=20