Dobutamine thallium 201 perfusion imaging in candidates for lung transplantation

Thallium-201 stress imaging is the most often used noninvasive test for detection of coronary artery disease. Its utility in patients with end-stage lung disease has not been defined.

Feasibility, safety, and reliability of thallium 201 perfusion imaging was evaluated in 23 consecutive candidates for lung transplantation. All underwent graded dobutamine thallium 201 single photon emission computed tomography imaging. The perfusion imaging results were correlated with results of coronary angiography, radionuclide angiography, and right heart catheterization.

The testing was completed without complications in all patients. No perfusion abnormality was detected in five patients, and none had evidence of coronary artery disease on coronary angiography. In 18 patients with abnormal thallium 201 imaging, coronary artery disease was detected in four patients only, and no angiographic data was available in three patients. Thus, in at least 11 of 23 patients, thallium 201 imaging was falsely positive. There was a trend toward lower left ventricular ejection fraction in patients with abnormal thallium 201 imaging. No correlation was found between thallium 201 results, pulmonary artery and right atrial pressures at rest. Possible noncoronary origin of the perfusion defects include the following (1) presence of sarcoid in the myocardium, (2) left ventricular attenuation by hypertrophied right ventricle, and (3) altered left ventricular anatomy, function, and coronary perfusion as a result of right ventricular pressure overload.

Dobutamine thallium 201 stress test can be safely performed in lung transplant candidates. However, its specificity for detection of coronary artery disease is low. Selective use of coronary angiography in patients with multiple risk factors is likely a more cost-effective approach.