Prognostic significance of increased thallium-201 lung uptake during dipyridamole myocardial scintigraphy: comparison with exercise scintigraphy.

OBJECTIVE: To compare the incidence of cardiac events among patients with increased lung uptake of thallium after dipyridamole stress, matched subjects without such uptake and matched subjects with increased lung uptake during exercise stress. DESIGN: Retrospective case control study based on quantitative and semiquantitative visual consensus analysis of thallium scintigraphy. SETTING: Nuclear cardiology laboratory of a university teaching hospital. PATIENTS: Thirty-six patients with increased lung activity after dipyridamole stress and two groups of matched control subjects identified from 3150 consecutive thallium single photon emission computed tomography studies. INTERVENTIONS: Telephone follow-up and chart reviews to determine the incidence of cardiac events. MAIN RESULTS: Cardiac events were significantly less frequent in the study group with increased lung uptake after dipyridamole stress (two of 36,5%) than in the control group with increased thallium lung uptake at exercise scintigraphy (nine of 36,25%; P = 0.046). CONCLUSIONS: Increased lung uptake of thallium has less ominous short term prognostic significance when observed in association with dipyridamole stress rather than with exercise.