Diagnostic value of peak filling rate derived from ECG-gated myocardial perfusion SPECT for detecting myocardial ischaemia in patients with non-obstructive coronary artery disease

Abstract

Background: Left ventricular (LV) diastolic dysfunction represents an earlier step of the ischaemic cascade. We tested the hypothesis that the index of LV diastolic function from electrocardiogram (ECG)-gated single photon emission computed tomography (SPECT) is useful in detecting myocardial ischaemia in patients with non-obstructive coronary artery disease (CAD).Methods: One-hundred-ten patients with non-obstructive CAD and summed redistribution score of zero were enrolled. Summed difference score (SDS) of ≥2 was considered as the presence of myocardial ischaemia. Peak filling rate (PFR) defined as the maximum dV/dt divided by LV end-diastolic volume was obtained as the index of LV diastolic function.Results: Of 110 patients with non-obstructive CAD, 51 patients had myocardial ischaemia. SDSs in patients with myocardial ischaemia and those without were 3.5 ± 1.8 and 0.4 ± 0.5, respectively (p < 0.001). PFRs after stress (r = −0.22, p = 0.02) and at redistribution (r = −0.24, p = 0.01) were inversely correlated with SDS. Multivariate logistic regression analysis showed that PFR at redistribution was an independent predictor of the presence of myocardial ischaemia in patients with non-obstructive CAD (odds ratio: 0.15, 95% confidence interval: 0.04–0.51, p = 0.002).Conclusion: Our data suggest that PFR, the index of LV diastolic function from ECG-gated SPECT, helps to find myocardial ischaemia in patients with non-obstructive CAD.