Prognosis in patients with spontaneous chest pain, a nondiagnostic electrocardiogram, normal cardiac enzymes, and no evidence of severe resting ischemia by quantitative technetium 99 m sestamibi tomographic imaging

Background. There are limited data addressing the outcome of patients with normal or near normal myocardial perfusion during chest pain at rest. The purpose of this study was to determine the prognosis of patients with spontaneous chest pain, a normal or nondiagnostic electrocardiogram, no enzymatic evidence of myocardial infarction, and no evidence of severe resting ischemia by quantitative technetium 99m (^99mTc) sestamibi imaging. Methods. In the study, 111 patients who fulfilled the above criteria were injected with ^99mTc sestamibi during resting chest pain and were followed for a median 2.7 years. Of the patients in the study group, 58% had coronary artery disease that was documented by clinical history or coronary angiography. Tomographic ^99mTc perfusion images were interpreted with a quantitative threshold technique initially developed to detect severely hypoperfused myocardium. The images were also interpreted qualitatively to detect patients with milder degrees of hypoperfused myocardium. Results. During follow-up 3 patients had cardiac deaths, 5 had nonfatal myocardial infarctions, and 21 underwent revascularization procedures (13 within 3 months and 8 more than 3 months after the sestamibi study). At 3 years, survival free of cardiac death was 97%, survival free of cardiac death or myocardial infarction was 91%, and survival of cardiac death, myocardial infarction, or late revascularization was 82%. Quantitative analysis of the scans revealed that 100% of patients without fixed defects had 3-year survival free of cardiac death versus 76% of patients who had fixed defects (p < 0.001). Mild to moderate resting ischemia by qualitative interpretation of the scans was present in 20% of patients, but this did not predict outcome. Conclusions. Patients with spontaneous chest pain and nonischemic quantitative ^99mTc sestamibi images were at reasonably low risk for hard cardiac events although some patients (18%) required revascularization.