Hemodynamic indices of myocardial dysfunction correlate with dipyridamole thallium-201 SPECT.
Important differences in hemodynamics and tracer kinetics occur with dipyridamole compared to exercise scintigraphy. To better understand the clinical significance of dipyridamole SPECT 201Tl scintigraphy, we examined the relationships between scintigraphy and clinical, and angiographic and hemodynamic variables in patients with CAD.


METHODS
Forty-nine subjects were divided into three study groups. Patients in Groups A (n = 11) and B (n = 20) had a low (<5%) likelihood of CAD. Group A underwent maximal exercise thallium stress testing. Group B underwent thallium dipyridamole scintigraphy. Group C (n = 18) consisted of patients with coronary artery disease who had dipyridamole thallium scintigraphy and cardiac catheterization within 2 wk. Thallium lung-to-myocardial ratio (L/M), left ventricular dilation and perfusion defect site were compared to hemodynamic, clinical and angiographic variables.


RESULTS
The Group A L/M ratio of 0.23 +/- 0.05 (mean +/- 1 s.d.) was significantly lower (p < 0.001) compared to the Group B L/M ratio of 0.31 +/- 0.05. In Group C, the UM ratio showed correlation with indices of left ventricular dysfunction including lower resting ejection fraction (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 ventricular dilation was associated with hemodynamic changes of ventricular failure including lower resting ejection fraction (p = 0.008, r = 0.88) and higher pulmonary capillary wedge pressure (p = 0.02, r =0.54). Immediate and delayed perfusion defect size showed good correlation with lower resting left ventricular ejection fraction (p = 0.02, r = 0.83, and p = 0.004, r = 0.91, respectively).


CONCLUSIONS
Lung uptake, left ventricular dilation and perfusion defect size show good correlation to hemodynamic indices of resting left ventricular dysfunction. A combination of these factors may be a better predictor of future cardiac events and prognosis.
Chin
B B
BB
Department of Radiology and Nuclear Medicine, Johns Hopkins University Hospital, Baltimore, Maryland 21287, USA.
Moshin
J
J
Bouchard
M
M
Berlin
J A
JA
Araujo
L I
LI
Alavi
A
A
D006328:Cardiac Catheterization; D016022:Case-Control Studies; D003326:Coronary Circulation / Q000502:physiology; D003327:Coronary Disease / Q000000981:diagnostic imaging* / Q000453:epidemiology; D004176:Dipyridamole; D005080:Exercise Test; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging*; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D013794:Thallium Radioisotopes; D015899:Tomography, Emission-Computed, Single-Photon; D014665:Vasodilator Agents; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging*
D013794:Thallium Radioisotopes; D014665:Vasodilator Agents; D004176:Dipyridamole