Correlation of diagnostic accuracy of dipyridamole thallium-201 myocardial scintigraphy and clinical findings during stress.

The relationship between dipyridamole thallium-201 myocardial single-photon emission computed tomography and clinical findings during stress testing was investigated in 57 patients (mean age 72 years), including 11 patients with normal coronary arteries. Systolic blood pressure decreased from 138.2 +/- 19.7 to 119.8 +/- 20.1 mmHg (mean: -13.8 +/- 6.6%) after dipyridamole infusion (0.568 mg/kg/4 min). Scintigraphic sensitivity for the diagnosis of coronary artery disease was higher in 30 patients with a systolic blood pressure decrease above the average value than in 27 patients with a blood pressure reduction of less than 14% (88% vs. 60%, p < 0.005). Reversible perfusion defects among stenosed coronary arteries were more frequent in the former group (73% vs. 27%, p < 0.001) with no difference in other clinical findings. In conclusion, systolic blood pressure change during stress testing was significantly correlated with dipyridamole-induced perfusion defects and detectability of coronary stenosis.