Morbidity and mortality increase when diastolic dysfunction accompanies coronary artery disease (CAD). An elevated stress (201)Tl lung-to-heart ratio (LHR) is a traditional marker of elevated left ventricular end-diastolic pressure (LVEDP), which adds prognostic value in CAD. Since the introduction of (99m)Tc-labeled agents, this valuable marker has been lost. Hence, there is only a limited ability to assess diastolic dysfunction by myocardial perfusion imaging (MPI).
Methods: Fifty-two consecutive patients with an ejection fraction of >or=45% underwent MPI and cardiac catheterization within 15 d. Peak filling rate (PFR), time to PFR (TPFR), and filling rate during the first third of diastole (1/3FR) were obtained from MPI with SPECT software. Resting (201)Tl LHR was calculated manually, and LVEDP was obtained at catheterization.
Results: PFR, TPFR, and 1/3FR correlated significantly with LVEDP (r= -0.53, 0.45, and -0.45, respectively; P=0.00005, 0.0009, and 0.0009, respectively), whereas resting (201)Tl LHR did not (r=0.10, P=0.49). Receiver-operating-characteristic curve analysis of PFR, TPFR, and 1/3FR for detecting LVEDPs of >or=18 mm Hg showed areas under the curve of 0.83, 0.75, and 0.80, respectively. The combination of PFR and 1/3FR showed a negative predictive value of 84%, a positive predictive value of 86%, and a specificity of 94%.
Conclusion: Diastolic filling variables obtained with the SPECT software showed a significant correlation with LVEDP. PFR, TPFR, and 1/3FR were superior to resting (201)Tl LHR and showed good sensitivity, specificity, and predictive power for detecting LVEDPs of >or=18 mm Hg. Hence, combining data on the presence of perfusion defects with data on diastolic impairments can be achieved by adding these variables to MPI results.