Incremental prognostic value of adenosine myocardial perfusion single-photon emission computed tomography in women with suspected coronary artery disease

Abstract

Adenosine myocardial perfusion single-photon emission computed tomography (SPECT) is now increasingly used for risk stratification of patients with known or suspected coronary artery disease. However, the incremental prognostic value of this test over clinical and historical information in a large series of women has not been examined. Thus, we studied 923 consecutive women who underwent adenosine technetium (Tc)-99m sestamibi myocardial perfusion SPECT and were followed-up for a mean period of 26 ± 8 months. During the follow-up period, 77 hard events (46 cardiac deaths and 31 nonfatal myocardial infarctions) occurred. The results of the perfusion scan significantly risk stratified the population; patients with normal scans had a low rate of nonfatal myocardial infarction and cardiac death (<1%/year of follow up). Patients with mildly abnormal scans had low cardiac death rates (0.9%/year of follow up); these rates increased as a function of scan abnormality (4.1% and 7.5% mortality per year of follow up in moderate and severely abnormal scans). Cox proportional hazards analysis demonstrated that after adjusting for prior myocardial infarction and diabetes mellitus (the most predictive individual clinical variables [global chi-square = 22.5, p <0.001]), as well as heart rate at rest (the most predictive physiologic variable [chi-square = 3.8; p = 0.05]), the most predictive nuclear variable (summed stress score [chi-square = 48.5; p <0.0001]) added significant incremental prognostic information (global chi-square increased from 22.5 to 56.2 [p <0.0001]). In conclusion, adenosine myocardial perfusion SPECT added significant incremental prognostic information to clinical and physiologic variables in women. Normal scans were associated with an excellent prognosis. In contrast, patients with moderately to severely abnormal scans were at a higher risk for future cardiac events.