Dipyridamole-atropine stress echocardiography versus exercise SPECT scintigraphy for detection of coronary artery disease in hypertensives with positive exercise test

OBJECTIVES: Many different stress echocardiographic and radionuclide perfusion imaging tests have been proposed for detecting epicardial coronary artery disease (CAD) in hypertensive patients. Their relative diagnostic and prognostic value has not been exactly established. BACKGROUND: A positive exercise electrocardiography test has a low diagnostic specificity in hypertensive patients and warrants for a complementary imaging test to confirm the diagnosis of coronary artery disease. METHODS: Hypertensive patients (n = 53), (29 males, aged 58 +/- 10 years) with normal left ventricular function detected by echocardiography and previous positive exercise test ( > or = 0.15 mV of ST segment depression on 12 lead electrocardiogram) underwent dipyridamole-atropine stress echocardiography (DASE) and thallium-201 stress/ rest myocardial single-photon emission computed tomography (SPECT). All patients had coronary angiography within 15 days and independently of imaging test results. RESULTS: Coronary angiogram showed significant ( > or = 50% qualitatively assessed diameter reduction) epicardial coronary artery disease in 23 (43%) patients. Sensitivity for detection of coronary artery disease was significantly higher for scintigraphy (DASE = 78% versus SPECT = 100%, P < 0.05) while specificity was higher for echo (DASE = 100% versus SPECT = 47%, P < 0.00001). Diagnostic accuracy was also higher for echo (DASE = 91% versus SPECT = 70%, P < 0.01). CONCLUSION: In patients with exercise-nduced ST segment depression, dipyridamole stress echo and SPECT perfusion scintigraphy are both good diagnostic options, with DASE characterized by higher specificity, lower sensitivity, and at least comparable diagnostic accuracy than SPECT.