HEMODYNAMIC INDEXES OF MYOCARDIAL DYSFUNCTION CORRELATE WITH DIPYRIDAMOLE TL-201 SPECT

Important differences in hemodynamics and tracer kinetics occur with d ipyridamole compared to exercise scintigraphy. To better understand th e clinical significance of dipyridamole SPECT Tl-201 scintigraphy, we examined the relationships between scintigraphy and clinical, and angi ographic and hemodynamic variables in patients with CAD. Methods: Fort y-nine subjects were divided into three study groups, Patients in Grou ps A (n = 11) and B (n = 20) had a low (<5%) likelihood of CAD. Group A underwent maximal exercise thallium stress testing. Group B underwen t thallium dipyridamole scintigraphy. Group C (n = 18) consisted of pa tients with coronary artery disease who had dipyridamole thallium scin tigraphy and cardiac catheterization within 2 wk. Thallium lung-to-myo cardial ratio (VM), left ventricular dilation and perfusion defect sit e were compared to hemodynamic, clinical and angiographic variables. R esults: The Group A VM ratio of 0.23 +/- 0.05 (mean +/- 1 s.d.) was si gnificantly lower (p < 0.001) compared to the Group B VM ratio of 0.31 +/- 0.05. In Group C, the VM ratio showed correlation with indices of left ventricular dysfunction including lower resting ejection fractio n (p = 0.02, r = 0.83), higher pulmonary capillary wedge pressure (p = 0.01, r = 0.58) and lower cardiac index (p = 0.03, r = 0.54). Left ve ntricular dilation was associated with hemodynamic changes of ventricu lar failure including lower resting ejection fraction (p = 0.008, r = 0.88) and higher pulmonary capillary wedge pressure (p = 0.02, r = 0.5 4). Immediate and delayed perfusion defect size showed good correlatio n with lower resting left ventricular ejection fraction p = 0.02 (r = 0.83, and p = 0.004, r = 0.91, respectively). Conclusion: Lung uptake, left ventricular dilation and perfusion defect size show good correla tion to hemodynamic indices of resting left ventricular dysfunction. A combination of these factors may be a better predictor of future card iac events and prognosis.