Left ventricular mechanical dyssynchrony analzyed by Tc-99m sestamibi SPECT and F-18 FDG PET in patients with ischemic cardiomyopathy and the prognostic value

Prognostic significance of phase analysis using SPECT myocardial perfusion imaging in heart failure: a systematic review and meta-analysis

Left ventricular mechanical dyssynchrony (LVMD) is an important prognostic factor for heart failure (HF). Phase analysis of myocardial perfusion SPECT is actively being researched to evaluate LVMD. We performed a systematic review and meta-analysis on the prognostic significance of LVMD using gated SPECT in HF patient. PubMed, Embase, and the Cochrane library were searched until January 10, 2024, for studies reporting the prognostic value of LVMD in HF patients using gated SPECT for outcomes of all-cause death, cardiac death, or major adverse cardiovascular event (MACE). Hazard ratios (HRs) along with their corresponding 95% confidence intervals (CIs) were combined through meta-analysis employing a random-effects model. Funnel plots and Egger's tests were utilized to evaluate publication bias, and trim-and-fill method were applied where bias was identified. Ten studies (2585 patients) were included; six on MACE and five on all-cause or cardiac death. Prognoses were worse in patients with LVMD assessed by SPECT than in those without LVMD, with the overall pooled HR for MACE being 2.05 (95% CI, 1.65-2.54). The pooled HR for all-cause or cardiac death was 2.08 (95% CI, 1.10-3.94); however, publication bias was present (p = 0.0024), and after adjustment, the prognostic value of LVMD was not statistically significant (HR, 1.24; 95% CI, 0.68-2.23). Assessing LVMD through myocardial perfusion SPECT proves to be a significant indicator of subsequent adverse cardiac events in HF patients. Utilizing phase analysis of SPECT could offer valuable insights for risk assessment and decision-making regarding therapy in HF patients.

Prognostic value of left ventricular mechanical dyssynchrony indices derived from gated myocardial perfusion SPECT in coronary artery disease: a systematic review and meta-analysis

PURPOSE

Left ventricular mechanical dyssynchrony (LVMD) is an important prognostic factor in coronary artery disease. A growing body of evidence indicates that LVMD parameters derived from phase analysis of gated myocardial SPECT may allow risk stratification for future cardiac events. We performed a systematic review and meta-analysis on the prognostic value of LVMD on gated SPECT in patients with coronary artery disease.

METHODS

PubMed, Embase, and the Cochrane library were searched until August 25, 2022, for studies reporting the prognostic value of LVMD on gated SPECT for outcomes of all-cause death, cardiac death, or major adverse cardiovascular event (MACE) in patients with coronary artery disease. Hazard ratios (HRs) and their 95% confidence intervals (CIs) were meta-analytically pooled using a random-effects model.

RESULTS

Nine studies (26,750 patients) were included in a qualitative synthesis. Among the SPECT LVMD parameters used in various studies, high phase standard deviation, phase bandwidth, and phase entropy were widely evaluated and reported to be associated with high rates of all-cause death, cardiac death, or MACE. For five studies (23,973 patients) in the quantitative synthesis, the pooled HR of LVMD for predicting MACE was 2.81 (95% CI 2.03-3.88). Studies using combined phase parameters to define LVMD showed higher HRs than a study using phase entropy (p = 0.0180).

CONCLUSION

LVMD from gated myocardial SPECT is a significant prognostic factor for coronary artery disease. Phase analysis of gated SPECT may be useful for accurate risk stratification and could be applied for clinical decision-making in such patients.

Assessment of left ventricular function with gated myocardial perfusion SPECT and gated myocardial FDG PET in patients with left ventricular mechanical dyssynchrony

BACKGROUND

Left ventricular mechanical dyssynchrony (LVMD) and left ventricular function are intertwined. Gated myocardial perfusion SPECT (MPS) and gated fluorodeoxyglucose positron emission computed tomography (FDG PET) is an elegant way for repeated assessment of myocardial dyssynchrony and myocardial function. To the knowledge of the authors at the time this manuscript was prepared, there was no comprehensive evaluation of the interplay of LVMD and left ventricular function as measured by gated MPS and gated FDG PET; as well as no evaluation of the agreement between the two methods.

METHODS

Patients were assigned to the reference cohort (RC) and the dyssynchrony cohort (DC) based on the phase analysis results of gated MPS datasets. Subsequently left ventricular function was analyzed.

RESULTS

We demonstrated that LVMD as detected by gated MPS is associated with a significantly higher end-diastolic volume (EDV) and end-systolic volume (ESV) as well as a significantly reduced left ventricular ejection fraction (LVEF) both in gated MPS and gated FDG PET imaging. In the RC and the DC SPECT and PET showed good agreement and generally high linear correlations with regard to left ventricular volumes and LVEF. In the combined cohort (RC and DC) increasing amounts of LVMD were associated with increasing left ventricular volumes as well as a decreasing LVEF. The association was strongest for the dyssynchrony parameter Entropy.

CONCLUSIONS

We demonstrated that gated SPECT and gated PET are useful tools in the evaluation of left ventricular function in patients with LVMD as detected by gated MPS. Increasing amounts of dyssynchrony were associated with an increasingly reduced myocardial function. For repeated measurements or therapy monitoring, the methods should not be used interchangeably.

The Value of Stress-Gated Blood Pool SPECT in Predicting Early Postoperative Period Complications in Ischemic Cardiomyopathy Patients: Focus on Mechanical Dyssynchrony

(1) Objective: The objective of this study was to assess the prognostic value of stress-gated blood pool SPECT (GBPS) estimates in patients with ischemic cardiomyopathy (ICM) in the early postoperative period. (2) Methods: A total of 57 patients (age 59.7 ± 6.6, 47 men) with ICM and LV ejection fraction (30 [27.5; 35]%) were enrolled in the study. Before surgical treatment, all patients underwent GBPS (rest-stress, dobutamine doses of 5/10/15 µg/kg/min). Stress-induced changes in left ventricular (LV) ejection fraction, peak ejection rate, volumes, and mechanical dyssynchrony (phase histogram standard deviation, phase entropy (PE), and phase histogram bandwidth) were estimated. Two-dimensional transthoracic echocardiography was performed baseline. Serum levels of NT-proBNP were analyzed with enzyme-linked immunoassay. (3) Results: After surgical treatment, patients were divided into two groups, one, with death, the need for an intra-aortic balloon pump (IABP) or/and inotropic support with a stay in the intensive care unit for more than two days and two, without complications in the early postoperative period (EPOP). Complicated EPOP (CEPOP) was observed in 17 (30%) patients (death-2, IABP-4, extra inotropic support in intensive care unit-11), and 40 patients had no complications (NCEPOP). GBPS showed differences in LV EDV (mL) (321 [268; 358] vs. 268 [242; 313], p = 0.02), LV ESV (mL) (242 [201; 282] vs. 196 [170; 230], p = 0.005), and stress-induced changes in PE (1 (-2; 3) vs. -2 (-4; 0), p = 0.02). Aortic cross-clamp time and stress-induced changes in PE between rest and dobutamine dose of 10 µg/kg/min were the only independent predictors of CEPOP. An increase in LV entropy ≥ 1 on the dobutamine dose of 10µg/kg/min in comparison to rest investigation showed AUC = 0.853 (sensitivity = 62%, specificity = 90%, PPV = 71%; NPV = 85%; p < 0.0001). Conclusion: Stress-induced changes in PE obtained during low-dose dobutamine GBPS are associated with a complicated course of the early postoperative period after surgical treatment for ICM.

Prognostic Role of Diastolic Left Ventricular Mechanical Dyssynchrony by Gated Single Photon Emission Computed Tomography Myocardial Perfusion Imaging in Post-Myocardial Infarction

Objective  This study is aimed to assess the prognostic value of diastolic left ventricular mechanical dyssynchrony (LVMD) measured by gated-single photon emission computed tomography (GSPECT) myocardial perfusion imaging (MPI) in post-myocardial infarction (MI). Subjects and Methods  The study was conducted on 106 post-MI from January 2015 to January 2019. First, the indices of diastolic LVMD phase standard deviation (PSD) and histogram bandwidth (HBW) of post-MI were measured using the Cardiac Emory Toolbox. Subsequently, the post-MI patients were followed up, and the primary endpoint was major adverse cardiac events (MACEs). Finally, the prognostic value of dyssynchrony parameters for MACE was analyzed by the receiver-operating characteristics curve and survival analyses. Results  With the cut-off values of 55.5 degrees of PSD, the sensitivity and specificity in prediction of MACE were 75% and 80.8%, with the cut-off values of 174.5 degrees of HBW, the sensitivity and specificity were 75% and 83.3% respectively. There was a significant difference of time to MACE between groups of PSD less than 55.5 degrees and more than 55.5 degrees. PSD, HBW, and left ventricle ejection fraction (LVEF) assessed on GSPECT were significant factors in the prediction of MACE. Conclusion  Diastolic LVMD parameters of PSD and HBW derived from GSPECT are significant prognostic factors in predicting MACE in post-MI patients.

Neurometabolism and Ventricular Dyssynchrony in Patients With Heart Failure and Reduced Ejection Fraction

BACKGROUND

The brain coordinates the heart through the autonomic nervous system (ANS). Numerous mediator signals along the brain-heart axis interact with the neuronal-metabolic system in heart failure (HF). Disturbances in cardio-neural interactions influence the disease progression in patients with HF.

OBJECTIVES

The purpose of this study was to investigate the interactome between ANS-associated neurometabolism and ventricular dyssynchrony in patients with heart failure with reduced ejection fraction (HFrEF). Further, we studied the association of neurometabolism with major arrhythmic events (MAEs).

METHODS

A total of 197 patients with HFrEF who underwent gated single-photon emission computed tomography myocardial perfusion imaging and the brain ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography were prospectively enrolled. Relationships between the brain metabolism and MAEs were assessed using Cox models and mediation analyses. Finally, metabolic central autonomic networks were constructed and statistically compared between patients with and without MAEs.

RESULTS

In total, 35 (17.8%) patients experienced MAEs during a median follow-up of 3.1 years. In patients with HFrEF (age 58 years [IQR: 50-64 years], left ventricular ejection fraction: 20.0% [IQR: 15.0%-25.0%]), glucose hypometabolism in the insula, hippocampus, amygdala, cingulate gyrus, and caudate nucleus were independent predictors for MAEs (all P < 0.05). Cerebral hypometabolism was related to ventricular dyssynchrony, which was the predominant risk factor of MAEs. Additionally, patients who experienced MAEs presented hypoconnectivity in the metabolic central autonomic network compared with those without MAEs (P < 0.05).

CONCLUSIONS

We found an interaction of the neuronal metabolic-ventricular dyssynchronization axis in HF, which might be related to MAEs. This new brain-heart axis could expand our understanding of the distinct pathomechanisms of HFrEF.

The assessment of left ventricular mechanical dyssynchrony from gated 99mTc-tetrofosmin SPECT and gated 18F-FDG PET by QGS: a comparative study

BACKGROUND

Due to partly conflicting studies, further research is warranted with the QGS software package, with regard to the performance of gated FDG PET phase analysis as compared to gated MPS as well as the establishment of possible cut-off values for FDG PET to define dyssynchrony.

METHODS

Gated MPS and gated FDG PET datasets of 93 patients were analyzed with the QGS software. BW, Phase SD, and Entropy were calculated and compared between the methods. The performance of gated PET to identify dyssynchrony was measured against SPECT as reference standard. ROC analysis was performed to identify the best discriminator of dyssynchrony and to define cut-off values.

RESULTS

BW and Phase SD differed significantly between the SPECT and PET. There was no significant difference in Entropy with a high linear correlation between methods. There was only moderate agreement between SPECT and PET to identify dyssynchrony. Entropy was the best single PET parameter to predict dyssynchrony with a cut-off point at 62%.

CONCLUSION

Gated MPS and gated FDG PET can assess LVMD. The methods cannot be used interchangeably. Establishing reference ranges and cut-off values is difficult due to the lack of an external gold standard. Further prospective research is necessary.