Nuclear Scan Strategy and Outcomes in Chest Pain Patients Value of Stress Testing with Dipyridamole or Adenosine

OBJECTIVE: To update the prognostic value of scan strategy with pharmacological stress agent in chest pain (CP) patients presenting with normal electrocardiography (ECG) and troponin. METHODS: Two consecutive nonrandomized series of patients with CP and negative first-line workup inclusive of serial ECG, serial troponin, and echocardiography underwent myocardial perfusion imaging single photon emission computed tomography (SPECT) in the emergency department. Of 170 patients enrolled, 52 patients underwent dipyridamole-SPECT and 118 adenosine-SPECT. Patients with perfusion defects underwent angiography, whereas the remaining patients were discharged and followed-up. Primary endpoint was the composite of nonfatal myocardial infarction, unstable angina, revascularization, and cardiovascular death at follow-up or the presence of coronary stenosis > 50% at angiography. RESULTS: At multivariate analysis, the presence of perfusion defects or hypertension was independent predictor of the primary endpoint. Sensitivity and negative predictive value were higher in patients subjected to adenosine-SPECT (95% and 99%, respectively) versus dipyridamole-SPECT (56% and 89%; yield 70% and 11%, respectively; P < 0.03). Of note, sensitivity, negative, and positive predictive values were high in patients with hypertension (100%, 93%, and 60%, respectively) or nonischemic echocardiography alterations (100%, 100%, and 100%, respectively). CONCLUSIONS: In CP patients, presenting with normal ECG and troponin, adenosine-SPECT adds incremental prognostic values to dipyridamole-SPECT. Costly scan strategy is more appropriate and avoids unnecessary angiograms in patients with hypertension or nonischemic echocardiography alterations.