Diagnostic and Prognostic Value of Dobutamine Thallium-201 Single-Photon Emission Computed Tomography After Heart Transplantation

Cardiac allograft vasculopathy (CAV) is a major cause of mortality in heart transplant recipients. We investigated the diagnostic and prognostic value of dobutamine thallium-201 ( 201Tl) single-photon emission computed tomography (SPECT) in heart transplant recipients. We studied 47 patients (age 51.6 ± 11.7 years, 37 men), at a mean of 34.0 ± 21.4 months after heart transplant, who received dobutamine 201Tl SPECT, echocardiography and coronary angiography within 1 month of each other. SPECT was considered abnormal in the presence of reversible or fixed defects in ≥2 segments. Significant CAV was defined as ≥50% luminal stenosis. Coronary angiograms were normal in 37 patients. Non-significant CAV was detected in 1 patient and significant CAV in 9 patients. The sensitivity, specificity, positive predictive value and negative predictive value of SPECT for the detection of significant angiographic CAV were 89%, 71%, 42% and 96%, respectively. Large reversible perfusion defects (≥6 segments) always indicated significant CAV. In patients with normal left ventricular function, a lung/heart ratio (LHR) of ≥0.37 during stress was also an independent predictor of significant CAV (odds ratio 15.5, p = 0.04). A higher stress LHR was associated with greater vessel involvement ( r = 0.516, p = 0.0002). Patients with impaired left ventricular function also had higher stress and resting LHR. Over 40.3 ± 21.9 months after the first SPECT, 1 patient developed significant angiographic CAV and another 4 had cardiac death. Large reversible perfusion defect was a significant predictor of cardiac death ( p = 0.002). Dobutamine 201Tl SPECT is a useful method for detecting patients with significant CAV and assessing prognosis. It is reasonable and safe to design individualized surveillance intensity of coronary angiography for post-transplant patients on the basis of non-invasive monitoring of dobutamine 201Tl testing.