Prognostic value of left ventricular dyssynchrony evaluated by gated myocardial perfusion imaging in patients with chronic kidney disease and normal perfusion defect scores

Stress phase bandwidth as a predictor of left ventricular reverse remodeling in patients with new-onset acute decompensated heart failure with reduced ejection fraction

BACKGROUND

Stress phase bandwidth (SPBW), assessed using single-photon emission computed tomography (SPECT), is considered to be a useful indicator of left ventricular dyssynchrony. However, few reports have examined whether it can be used as an indicator for improvement of left ventricular ejection fraction (LVEF) in new-onset heart failure with reduced ejection fraction (HFrEF).

METHODS AND RESULTS

A total of 64 patients (mean age 56 years, 39 male) who were admitted to our hospital with new-onset non-ischemic HFrEF (median LVEF 24.7%) from January 2018 to December 2022 in the SAKURA-HF registry and underwent SPECT were enrolled. The relationship between SPBW in the acute phase and LVEF improvement in the chronic phase was retrospectively investigated in the present study. LVEF improved significantly in the 36 patients (from 27.1 to 62.8%, p < 0.001). Guideline-directed medical therapy in both groups was comparable. SPBW was significantly lower in the group with improved LVEF (median 55.5° vs. 79.0°, p = 0.010). Logistic regression analysis revealed that SPBW was an independent predictor for LVEF improvement. Moreover, an SPBW of 71.0° was suggested as a possible cut-off value.

CONCLUSIONS

SPBW may predict the improvement of LVEF in new-onset non-ischemic HFrEF, suggesting its potential utility in heart failure management.

Left ventricular mechanical dyssynchrony after chemotherapy in breast cancer patients with normal rest gated SPECT-MPI

OBJECTIVES

Early diagnosis of chemotherapy-induced cardiotoxicity plays an important role in preventing heart failure. The main aim of our study was to assess left ventricular (LV) dyssynchrony measured by phase analysis of gated single-photon emission computed tomography (SPECT) as an early sign of cardiotoxicity after breast cancer chemotherapy.

METHODS

This cross-sectional study was conducted on patients with stage ≤ 3 breast cancer and no history of cardiovascular disease or diabetes. After mastectomy, the patients underwent rest gated SPECT myocardial perfusion imaging (MPI). Sixty patients with normal gated SPECT-MPI were selected and the imaging was performed after chemotherapy with doxorubicin, cyclophosphamide and paclitaxel. LV function and contractility parameters were extracted by QGS software and the results were compared with the t test method. The abnormality of at least one of the three phase analysis indices was considered as left ventricular dyssynchrony (LVD).

RESULTS

The average LV end-systolic volume and ejection fraction (LVEF) before and after chemotherapy were (16.2 ± 8.0 ml and 21.6 ± 11.6 ml) and (73.4 ± 7.9% and 67.5 ± 9.2%) respectively, which showed a significant decrease (P < 0.05). In 2 patients (3.3%), the LVEF decreased to less than 50% after chemotherapy. The average parameters of left ventricular contractility before and after chemotherapy were, respectively, as follows: PHB (24.1 ± 7.5 and 33.8 ± 16.4), PSD (9.4 ± 6.1 and 5.7 ± 1.9) and entropy (28.9 ± 7.1 and 35.6 ± 9.7), which showed a significant increase (P < 0.05). LVD was observed in 14 patients (23.4%) after chemotherapy and prevalence of LVD was significantly higher in patients who had received a cumulative dose of doxorubicin of more than 400 mg/m2 (P = 0.005). There was no relationship between age and body mass index with the incidence of LVD after chemotherapy (P > 0.05).

CONCLUSION

Using phase analysis of gated SPECT-MPI, chemotherapy-induced LVD was seen in a significant number of patients with breast cancer, especially with a high cumulative dose of doxorubicin. LVD might indicate chemotherapy-induced cardiotoxicity before LVEF becomes abnormal.

Usefulness of phase analysis on ECG gated single photon emission computed tomography myocardial perfusion imaging

Electrocardiogram (ECG)-gated single photon emission computed tomography myocardial perfusion imaging (GSPECT-MPI) is widely used for assessing coronary artery disease. Phase analysis on GSPECT-MPI can assess left ventricular mechanical dyssynchrony quantitatively on standard GSPECT-MPI alongside myocardial perfusion and function assessment. It has been shown that phase variables by GSPECT-MPI correlate well with tissue Doppler imaging by echocardiography. Main phase variables quantified by GSPECT-MPI are entropy, bandwidth, and phase standard deviation. Although those variables are automatically obtained from several software packages including Quantitative Gated SPECT and Emory Cardiac Toolbox, the methods for their measurement vary in each package. Several studies have shown that phase analysis has predictive value for response to cardiac resynchronization therapy and prognostic value for future adverse cardiac events beyond standard GSPECT-MPI variables. In this review, we summarize the basics of phase analysis on GSPECT-MPI and usefulness of phase analysis in clinical practice.

Prognostic Value of Phase Analysis for Predicting Adverse Cardiac Events Beyond Conventional Single-Photon Emission Computed Tomography Variables: Results From the REFINE SPECT Registry

BACKGROUND

Phase analysis of single-photon emission computed tomography myocardial perfusion imaging provides dyssynchrony information which correlates well with assessments by echocardiography, but the independent prognostic significance is not well defined. This study assessed the independent prognostic value of single-photon emission computed tomography-myocardial perfusion imaging phase analysis in the largest multinational registry to date across all modalities.

METHODS

From the REFINE SPECT (Registry of Fast Myocardial Perfusion Imaging With Next Generation SPECT), a total of 19 210 patients were included (mean age 63.8±12.0 years and 56% males). Poststress total perfusion deficit, left ventricular ejection fraction, and phase variables (phase entropy, bandwidth, and SD) were obtained automatically. Cox proportional hazards analyses were performed to assess associations with major adverse cardiac events (MACE).

RESULTS

During a follow-up of 4.5±1.7 years, 2673 (13.9%) patients experienced MACE. Annualized MACE rates increased with phase variables and were ≈4-fold higher between the second and highest decile group for entropy (1.7% versus 6.7%). Optimal phase variable cutoff values stratified MACE risk in patients with normal and abnormal total perfusion deficit and left ventricular ejection fraction. Only entropy was independently associated with MACE. The addition of phase entropy significantly improved the discriminatory power for MACE prediction when added to the model with total perfusion deficit and left ventricular ejection fraction (P<0.0001).

CONCLUSIONS

In a largest to date imaging study, widely representative, international cohort, phase variables were independently associated with MACE and improved risk stratification for MACE beyond the prediction by perfusion and left ventricular ejection fraction assessment alone. Phase analysis can be obtained fully automatically, without additional radiation exposure or cost to improve MACE risk prediction and, therefore, should be routinely reported for single-photon emission computed tomography-myocardial perfusion imaging studies.

Prognostic value of phase analysis on gated single photon emission computed tomography in patients with cardiac sarcoidosis

BACKGROUND

We aimed to determine the correlation between phase analysis, reflecting the heterogeneity of perfusion defects, and the dyssynchrony of the left ventricle wall motion, and adverse cardiac events in cardiac sarcoidosis (CS) patients.

METHODS

Fifty-seven consecutive patients with diagnosed CS (64 [IQR 55-71] years old, 14 males), who underwent 18F-FDG PET/CT and ECG-gated SPECT, were studied. FDG PET was analysed to measure cardiac metabolic volume (CMV), and total lesion glycolysis (TLG). The SPECT findings, such as LVEF, Summed Rest Score (SRS), bandwidth (BW) were evaluated.

RESULTS

The median of BW was 56° (IQR 40-95). BW showed a strong inverse correlation with LVEF (r = - 0.60, P < 0.0001), and positive correlation with SRS (r = 0.82, P < 0.0001). However, there were no significant correlations between BW and CMV or TLG. The Kaplan-Meier curves revealed a significantly higher rate of MACE in the high BW group (BW > 56°) than the low BW group (BW ≤ 56°) (15.1%/years vs. 4.4%/years, P = 0.025). In multivariable analysis, BW was a significant independent predictor of MACE (P = 0.015).

CONCLUSION

Phase analysis on gated SPECT was a significant and independent predictor of MACE in patients with CS.

Left ventricular end-systolic contractile entropy can predict cardiac prognosis in patients with complete left bundle branch block

BACKGROUND

Several patients with complete left bundle branch block (CLBBB) show left ventricular (LV) dyssynchrony and poor cardiac prognosis. However, the prognostic value of LV end-systolic contractile entropy which was measured by single-photon emission computer tomography (SPECT) has not been elucidated in patients with CLBBB.

METHODS AND RESULTS

We recruited consecutive 115 sinus-rhythm patients with CLBBB who underwent ECG-gated 201TlCl-SPECT. After 30 days of observation, finally 102 patients (75.2 ± 9.5 years, 62 male) were enrolled and observed retrospectively for a median of 671 days. Twenty-five patients fell into major cardiac events. Multivariate Cox regression analysis showed estimated glomerular filtration rate (eGFR) ≤ 39.35 mL/min and entropy ≥ 79% were significant and independent predictors for major cardiac events (hazard ratio: 4.256 and 7.587, P value = 0.006 and < 0.001, respectively). Machine learning (Random Forest method) revealed eGFR and entropy had higher feature importance than other predictors (0.140 and 0.138, respectively). Kaplan-Meyer curve analysis demonstrated that the group with entropy ≥ 79% and eGFR ≤ 39.36 mL/min had the worst cardiac prognosis (Logrank: P = 0.002).

CONCLUSIONS

Left ventricular end-systolic contractile entropy predicts poor cardiac prognosis in patients with CLBBB, which may be more valuable than the other parameters of SPECT.

Prognostic value of left ventricular mechanical dyssynchrony indices in long-standing type II diabetes mellitus with normal perfusion and left ventricular systolic functions on SPECT-MPI

OBJECTIVE

To test whether phase analysis indices from SPECT-MPI for left ventricular mechanical dyssynchrony (LVMD) are predictors of major adverse cardiac events (MACEs) in long-standing diabetes mellitus (DM).

METHODS

A total of 136 DM patients with normal perfusion and left ventricular systolic functions were followed up for about two years and divided into two groups according to the presence and the absence of MACEs.

RESULT

Thirteen (9.5%) patients experienced MACEs during follow-up. Patients experiencing MACEs showed significantly higher phase standard deviation (PSD) and wider phase bandwidth (PBW) than those who did not. Moreover, both PSD and PBW showed significant correlations (r = 0.25 and 0.27; P < 0.05) with duration of DM. Logistic regression analysis revealed significant associations of DM duration, microvascular complications, and LVMD indices for predicting MACEs. Kaplan-Meier event-free survival analysis revealed significantly higher rate of MACEs (Logrank = 10.02; P = 0.001) in patients with high PSD and wide PBW. An overall fit model consisting of high-PSD and wide-PBW group was improved with the addition of microvascular complications (χ2 = 15.9; P = 0.03) and further by addition of DM duration of ≥ 15 years (χ2 = 24.3; P = 0.007) as variables.

CONCLUSION

LVMD indices are novel prognostic markers in diabetic patients with normal perfusion and left ventricular systolic functions and their increases in magnitudes with DM-duration and in the presence of microvascular complications.

Hyperpolarized 129Xe Time-of-Flight MR Imaging of Perfusion and Brain Function

Perfusion measurements can provide vital information about the homeostasis of an organ and can therefore be used as biomarkers to diagnose a variety of cardiovascular, renal, and neurological diseases. Currently, the most common techniques to measure perfusion are ¹⁵O positron emission tomography (PET), xenon-enhanced computed tomography (CT), single photon emission computed tomography (SPECT), dynamic contrast enhanced (DCE) MRI, and arterial spin labeling (ASL) MRI. Here, we show how regional perfusion can be quantitively measured with magnetic resonance imaging (MRI) using time-resolved depolarization of hyperpolarized (HP) xenon-129 (¹²⁹Xe), and the application of this approach to detect changes in cerebral blood flow (CBF) due to a hemodynamic response in response to brain stimuli. The investigated HP ¹²⁹Xe Time-of-Flight (TOF) technique produced perfusion images with an average signal-to-noise ratio (SNR) of 10.35. Furthermore, to our knowledge, the first hemodynamic response (HDR) map was acquired in healthy volunteers using the HP ¹²⁹Xe TOF imaging. Responses to visual and motor stimuli were observed. The acquired HP TOF HDR maps correlated well with traditional proton blood oxygenation level-dependent functional MRI. Overall, this study expands the field of HP MRI with a novel dynamic imaging technique suitable for rapid and quantitative perfusion imaging.

Review of cardiovascular imaging in the Journal of Nuclear Cardiology 2019: Single-photon emission computed tomography

In 2019, the Journal of Nuclear Cardiology published excellent articles pertaining to imaging in patients with cardiovascular disease. In this review, we will summarize a selection of these articles to provide a concise review of the main advancements that have recently occurred in the field and provide the reader with an opportunity to review a wide selection of articles. In the first article of this 2-part series, we focused on publications dealing with positron emission tomography, computed tomography, and magnetic resonance. This review will place emphasis on myocardial perfusion imaging using single-photon emission computed tomography summarizing advances in the field including in diagnosis and prognosis, non-perfusion variables, safety of testing, imaging in patients with heart failure and renal disease.

The role of nuclear medicine in assessments of cardiac dyssynchrony

Radionuclide imaging has an advantage for quantitative analyses of the tracer concentration and its temporal changes. Myocardial perfusion and function have been adapted for synchrony analyses. Extracted parameters have been demonstrated to measure ventricular synchrony and even to predict CRT outcomes. ERNA has the advantages of higher temporal resolution, greater reproducibility, and the volumetric analysis of both ventricles that can be applied for analyses of intraventricular synchrony and interventricular synchrony. Several software packages such as Quantitative Gated SPECT, the Emory Cardiac Toolbox, cardioREPO, and Heart Function View are available to assess the LV dyssynchrony parameters from GSPECT. A count-based method is applied to extract the amplitude and phase from each of the reconstructed GSPECT short-axis datasets throughout the cardiac cycle and then subjected to a Fourier analysis, the results of which are displayed on a polar map and histogram. Some of the parameters such as the bandwidth (expressed as the 95% width of the phase histogram) and the standard deviation of the phase are obtained by the phase histogram to assess the intraventricular synchrony. This review paper focuses on the application of the LV dyssynchrony parameters estimated by cardiac SPECT in patients with a heart disease.

Assessment of dyssynchrony by gated myocardial perfusion imaging does not improve patient management

Clinical trials have demonstrated improved outcomes with cardiac resynchronization therapy in patients with heart failure and electrical evidence of dyssynchrony. There has been intense effort at developing imaging markers of dyssynchrony with the aim of improved risk stratification. However, these efforts have not been fruitful to date. This article discusses mechanisms of cardiac dyssynchrony, reviews clinical data supporting resynchronization therapy, and addresses the lack of convincing evidence to support the use of noninvasive imaging measures of dyssynchrony in improving patient management.

Mechanical dyssynchrony and diastolic dysfunction are common in LVH: a pilot correlation study using Doppler echocardiography and CZT gated-SPECT MPI

Hypertrophic cardiomyopathy (HCM) is an often under-diagnosed cause of left ventricular hypertrophy (LVH). It affects 1/500 of the population, is the most commonly inherited cardiovascular disorder, and can present in apical, concentric, or septal forms. Although most patients are asymptomatic, sudden cardiac death can be the initial presentation of HCM. By retrospectively enrolling patients suspected of having three different types of HCM in the absence of epicardial coronary stenosis, we aimed to examine systolic and diastolic dysfunction and perfusion abnormalities using both Doppler echocardiography and state-of-the-art gated single-photon emission computerized tomography (SPECT) myocardial perfusion imaging (MPI) with a cadmium-zinc-telluride camera and thallium-201. Both regional perfusion and gated SPECT parameters were collected in addition to diastolic parameters from Doppler echocardiography. The results showed that mild ischemia was common in patients suspected of having HCM, with a mean summed stress score of 4.7 ± 4.9 (score 0–4 in 17-segment model). The patients with HCM were associated with discernible left ventricular mechanical dyssynchrony, especially those with the apical form. In addition, diastolic dysfunction was prevalent and early to late ventricular filling velocity ratios were significantly different between groups. By combining gated-MPI and Doppler data, the trivial functional changes in HCM may be identified.