Single photon emission computed tomography myocardial perfusion imaging to detect cardiac allograft vasculopathy

Cardiac allograft vasculopathy (CAV) is a major cause of morbidity and mortality in cardiac transplant recipients. This study evaluates the usefulness of single photon emission computed tomography (SPECT) and various SPECT-derived diastolic variables to detect CAV in heart transplant patients.

A retrospective review of 141 SPECT studies with corresponding coronary angiograms within 12 months was performed on 99 transplant recipients. Diastolic function was assessed using computer-derived measures of peak filling rate (PFR), time to peak filling rate (TPFR), and mean first one-third filling rate (MFR/3). Angiography identified CAV in 53 of the 141 studies (38%). Of the 53, SPECT identified 7 with reversible myocardial defects (sensitivity 13%) and stress-induced electrocardiographic evidence of ischaemia was seen in one patient (sensitivity 2%). SPECT imaging was negative in 86 of the 88 negative coronary angiograms (specificity 98%). The positive predictive value and negative predictive value were 78 and 65%, respectively. If a more stringent definition of CAV was used (≥70% stenosis), the sensitivity and specificity were unchanged (14 and 98%, respectively). There was no statistical difference in diastolic variables between patients with or without angiographic evidence of CAV in regard to PFR (3.57 ± 1.14 vs. 3.18 ± 1.21 EDV/s, P = 0.90), TPFR (149 ± 32 vs. 153 ± 43 ms, P = 0.33), or MFR/3 (1.37 ± 0.43 vs. 1.27 ± 0.42 EDV/s, P = 0.94).

Adenosine stress/rest technetium-99m tetrofosmin-gated SPECT is not a sensitive test for detection of CAV in heart transplant recipients. Diastolic dysfunction, as assessed by SPECT, was not shown to be associated with development of CAV.