Coronary computed tomography angiography (CCTA) is the most commonly used modality for noninvasive plaque imaging in clinical settings. Characteristics of rupture-prone vulnerable plaques include positive remodeling, low attenuation, and napkin-ring sign in CCTA. About 60% of all vulnerable plaques have these characteristics, and these coronary lesions often result in plaque rupture. Identification of such groupings of coronary artery characteristics has been used to predict cardiovascular events.
Purpose: “Heart Function View (HFV)” is a software that performs phase analysis as well as functional assessment of the left ventricle (LV) using myocardial perfusion single photon emission computed tomography (SPECT) (MPS). Phase analysis-derived phase standard deviation (PhSD) and histogram bandwidth (PhHB) are good indices for detecting LV dyssyncrony. We aimed to examine whether PhHB and/or PhSD (PhHB/PhSD) are useful clinical indicators that reflect the severity of heart failure (HF) in comparison with the LV ejection fraction (EF). Methods: Patients underwent 99mTc-tetrofosmin quantitative gated MPS including treadmill exercise. In HFV analyses, patients with induced ischemia were excluded. Phase and time-volume curve analyses were performed using HFV (n=66). Results: PhHB/PhSD correlated with LV end-diastolic volume (EDV), end-systolic volume (ESV), the first-third filling fraction (1/3FF), and peak filling rate (PFR) as well as echocardiography tissue Doppler-derived E/e’ as hemodynamic parameters of HF severity. LVEF also correlated with these hemodynamic parameters, except for 1/3FF. PhHB/PhSD positively correlated with log BNP as a neurohumoral marker of HF severity. LVEF negatively correlated with log BNP. PhHB/PhSD negatively correlated with exercise capacity as physiological indicators of HF severity, whereas LVEF did not. PhHB/PhSD were significantly greater in patients receiving cardiac resynchronization therapy (CRT, n=6) than in non-CRT patients (n=66), whereas LVEF were lower. Conclusion: PhHB/PhSD, similar to LVEF, are useful clinical indicators for evaluating HF severity. However, the clinical significance of LVEF and PhHB/PhSD differ. Thus, a phase analysis may additively offer useful information for the management of HF.