Initial application of three-dimensional speckle-tracking echocardiography to detect subclinical left ventricular dysfunction and stratify cardiomyopathy associated with Duchenne muscular dystrophy in children

Early assessment of cardiomyopathy in Duchenne patients by means of longitudinal strain echocardiography

INTRODUCTION

The diagnosis of Duchenne-linked cardiomyopathy may be challenging. Conventional echocardiographic measurements typically show deterioration beyond the second decade. Global longitudinal strain has been proposed as an earlier marker than left ventricular ejection fraction.

MATERIAL AND METHODS

A prospective, observational, cross-sectional, case-control study was carried out. Both Duchenne patients and control subjects underwent transthoracic echocardiogram in order to assess left ventricle function. Bayesian linear regression was the main tool for inference. Age effects were parameterised by means of a spline function because of its simplicity to characterise continuous variables and smooth contributions. The posterior distribution of the marginal age effects was used to assess the earliest age of deterioration of each marker.

RESULTS

Sixteen Duchenne patients and twenty-two healthy male subjects were enrolled. On overage, cardiac function measures were found for ejection fraction and longitudinal strain among different groups. Age effects on global longitudinal strain are more reliably found at ages of 6 and above, while ejection fraction starts to deteriorate at an older age. Progressive left ventricular dysfunction in Duchenne patients is one of the key issues and starts at an early age with subtle symptoms.

CONCLUSION

This cross-sectional study provides supporting evidence that global longitudinal strain is an earlier marker of disease progression than ejection fraction in Duchenne patients.

Spatial and Temporal Non-Uniform Changes in Left Ventricular Myocardial Strain in Dogs with Duchenne Muscular Dystrophy

BACKGROUND

Understanding and effectively treating dystrophin-deficient cardiomyopathy is of high importance for Duchenne muscular dystrophy (DMD) patients due to their prolonged lifespan. We used two-dimensional speckle tracking echocardiography to analyze more deeply the non-uniformity of myocardial strain within the left ventricle during the progression of cardiomyopathy in golden retriever muscular dystrophy (GRMD) dogs.

METHODS

The circumferential strain (CS) and longitudinal strain (LS) of left ventricular (LV) endocardial, middle and epicardial layers were analyzed from three parasternal short-axis views and three apical views, respectively, in GRMD (n = 22) and healthy control dogs (n = 7) from 2 to 24 months of age.

RESULTS

In GRMD dogs, despite normal global systolic function (normal LV fractional shortening and ejection fraction), a reduction in systolic CS was detected in the three layers of the LV apex but not in the LV middle-chamber and base at 2 months of age. This spatial heterogeneity in CS progressed with age, whereas a decrease in systolic LS could be detected early at 2 months of age in the three layers of the LV wall from three apical views.

CONCLUSIONS

Analyzing the evolution of myocardial CS and LS in GRMD dogs reveals spatial and temporal non-uniform alterations of LV myocardial strain, providing new insights into the progression of dystrophin-deficient cardiomyopathy in this relevant model of DMD.

Localized strain characterization of cardiomyopathy in Duchenne muscular dystrophy using novel 4D kinematic analysis of cine cardiovascular magnetic resonance

BACKGROUND

Cardiomyopathy (CMP) is the most common cause of mortality in Duchenne muscular dystrophy (DMD), though the age of onset and clinical progression vary. We applied a novel 4D (3D + time) strain analysis method using cine cardiovascular magnetic resonance (CMR) imaging data to determine if localized strain metrics derived from 4D image analysis would be sensitive and specific for characterizing DMD CMP.

METHODS

We analyzed short-axis cine CMR image stacks from 43 DMD patients (median age: 12.23 yrs [10.6-16.5]; [interquartile range]) and 25 male healthy controls (median age: 16.2 yrs [13.3-20.7]). A subset of 25 male DMD patients age-matched to the controls (median age: 15.7 yrs [14.0-17.8]) was used for comparative metrics. CMR images were compiled into 4D sequences for feature-tracking strain analysis using custom-built software. Unpaired t-test and receiver operator characteristic area under the curve (AUC) analysis were used to determine statistical significance. Spearman's rho was used to determine correlation.

RESULTS

DMD patients had a range of CMP severity: 15 (35% of total) had left ventricular ejection fraction (LVEF) > 55% with no findings of myocardial late gadolinium enhancement (LGE), 15 (35%) had findings of LGE with LVEF > 55% and 13 (30%) had LGE with LVEF < 55%. The magnitude of the peak basal circumferential strain, basal radial strain, and basal surface area strain were all significantly decreased in DMD patients relative to healthy controls (p < 0.001) with AUC values of 0.80, 0.89, and 0.84 respectively for peak strain and 0.96, 0.91, and 0.98 respectively for systolic strain rate. Peak basal radial strain, basal radial systolic strain rate, and basal circumferential systolic strain rate magnitude values were also significantly decreased in mild CMP (No LGE, LVEF > 55%) compared to a healthy control group (p < 0.001 for all). Surface area strain significantly correlated with LVEF and extracellular volume (ECV) respectively in the basal (rho = - 0.45, 0.40), mid (rho = - 0.46, 0.46), and apical (rho = - 0.42, 0.47) regions.

CONCLUSION

Strain analysis of 3D cine CMR images in DMD CMP patients generates localized kinematic parameters that strongly differentiate disease from control and correlate with LVEF and ECV.

Myocardial strain imaging in Duchenne muscular dystrophy

Cardiomyopathy (CM) is the leading cause of death for individuals with Duchenne muscular dystrophy (DMD). While DMD CM progresses rapidly and fatally for some in teenage years, others can live relatively symptom-free into their thirties or forties. Because CM progression is variable, there is a critical need for biomarkers to detect early onset and rapid progression. Despite recent advances in imaging and analysis, there are still no reliable methods to detect the onset or progression rate of DMD CM. Cardiac strain imaging is a promising technique that has proven valuable in DMD CM assessment, though much more work has been done in adult CM patients. In this review, we address the role of strain imaging in DMD, the mechanical and functional parameters used for clinical assessment, and discuss the gaps where emerging imaging techniques could help better characterize CM progression in DMD. Prominent among these emerging techniques are strain assessment from 3D imaging and development of deep learning algorithms for automated strain assessment. Improved techniques in tracking the progression of CM may help to bridge a crucial gap in optimizing clinical treatment for this devastating disease and pave the way for future research and innovation through the definition of robust imaging biomarkers and clinical trial endpoints.

Two-dimensional speckle tracking echocardiography demonstrates improved myocardial function after intravenous infusion of bone marrow mesenchymal stem in the X-Linked muscular dystrophy mice

Background

Bone marrow mesenchymal stem cells (BMSCs) are commonly used in regenerative medicine. However, it is not clear whether transplantation of BMSCs can improve cardiac function of the X-Linked Muscular Dystrophy Mice (mdx) and how to detect it. We aimed to investigate the role of speckle tracking echocardiography (STE) in detecting cardiac function of the BMSCs-transplanted mdx in comparison with the untreated mdx.

Methods

The experimental mice were divided into the BMSCs-transplanted mdx, untreated mdx, and control mice groups (n = 6 per group). The BMSCs were transplanted via tail vein injections into a subset of mdx at 20 weeks of age. After four weeks, the cardiac functional parameters of all the mice in the 3 groups were analyzed by echocardiography. Then, all the mice were sacrificed, and the cardiac tissues were harvested and analyzed by immunofluorescence. The serum biochemical parameters were also analyzed to determine the beneficial effects of BMSCs transplantation.

Results

Traditional echocardiography parameters did not show statistically significant differences after BMSCs transplantation for the three groups of mice. In comparison with the control group, mdx showed significantly lower left ventricular (LV) STE parameters in both the long-axis and short-axis LV images (P < 0.05). However, BMSCs-transplanted mdx showed improvements in several STE parameters including significant increases in a few STE parameters (P < 0.05). Immunofluorescence staining of the myocardium tissues showed statistically significant differences between the mdx and the control mice (P < 0.05), and the mdx transplanted with BMSCs demonstrated significantly improvement compared with the untreated mdx (P < 0.05).

Conclusion

This study demonstrated that the early reduction in the LV systolic and diastolic function in the mdx were accurately detected by STE. Furthermore, our study demonstrated that the transplantation of BMSCs significantly improved myocardial function in the mdx.

Anti-Remodeling Cardiac Therapy in Patients With Duchenne Muscular Dystrophy, Meta-Analysis Study

Background: Almost all Duchenne muscular dystrophy (DMD) patients that reach their 30s present cardiomyopathy. As a result, this population remains under-treated. There is no sufficient proof of the efficacy of anti-remodeling cardiac therapy for DMD cardiomyopathy (DMDCM). We aim to assess the efficacy of anti-remodeling cardiac therapy for DMDCM by using meta-analysis.

Methods: PubMed (MEDLINE), Embase, and Cochrane library were searched through January 2021. Randomized control trials, case-control studies, and observational studies that reported assessments of cardiovascular outcomes and death of participants using angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, beta-blockers, mineralocorticoid-receptor antagonists and Ivabradine, were included. The primary outcome was total mortality. Secondary outcomes included changes in left ventricular ejection fraction (LVEF), serum natriuretic peptide levels (BNP), and heart rate (HR). Data were extracted for eligibility by two independent reviewers. Random-effects meta-analysis was used to pool results.

Results: Twelve studies with 439 patients were included in our meta-analysis. Treated patients have lower HR, mean difference of −17 beats per minute (CI [−25]–[−9], p < 0.01). The LVEF was improved in treated patients, with a mean difference of LVEF of 3.77% (CI 0.44–7.12, p < 0.03). Although mortality rates did not reach statistical significance there was a trend for total mortality reduction (hazard ratio 0.36, CI (0.1–1.25), p = 0.107) and for BNP reduction (SSMD: 0.141, CI ([−0.19]–[0.47]), p = 0.3).

Conclusion: Pharmacologic treatment for DMDCM patients is associated with decreased HR and improved LVEF. Therefore, DMDCM patients may benefit from implementing guideline therapy for HF.

Impaired myocardial strain in early stage of Duchenne muscular dystrophy: its relation with age and motor performance

Duchenne muscular dystrophy (DMD) is complicated by an early and progressive left ventricular (LV) dysfunction. Despite the reduction of ejection fraction (EF) usually manifests in the second decade, subtle alterations in LV mechanics can be detected earlier. Longitudinal and circumferential LV deformation, evaluated by speckle tracking echocardiography (STE), are considered sensitive markers of early dysfunction. We retrospectively examined clinical and echocardiographic data of 32 DMD children with preserved LV function. According to the median age, patients were then divided into younger and older than 9 years, and compared to 24 age-matched healthy subjects. Six-minute-walk test (6MWT), North Star Ambulatory Assessment (NSAA), and a comprehensive cardiac evaluation were performed. Although EF was within the normal range, DMD patients had significantly lower values than healthy controls, and the same occurred for the remaining conventional systolic and diastolic indices. Global longitudinal strain (GLS) was reduced in all patients (older and younger, both p < 0.001). Global circumferential strain (GCS) was reduced only in older patients (< 0.001). Both GLS and GCS worsened with age in DMD patients (GLS p = 0.005; GCS p = 0.024). GLS was significantly worse in the apical segments and in the postero-lateral wall. GCS in the antero-septal, anterior and antero-lateral segments was significantly reduced in older patients, with a prevalent involvement of the sole septal wall in the younger boys. 6MWT appeared to be correlated inversely to GLS and directly to EF. A longitudinal evaluation should be scheduled in DMD boys to assess the global cardiac performance over time and to evaluate the impact of therapies.

Usefulness of speckle-tracking echocardiography for early detection in children with Duchenne muscular dystrophy: a meta-analysis and trial sequential analysis

Background

Duchenne muscular dystrophy (DMD) is the most common form of inherited muscle disease in children. The incidence of cardiomyopathy induced by DMD increases with age. Left ventricular ejection fraction usually fails to reflect the subclinical left ventricular dysfunction. Several studies have assessed this dysfunction using myocardial strain measured by speckle-tracking echocardiography (STE). However, the results were inconsistent and incomplete.

Methods

Several databases were searched from their inception to February 5, 2020. The summarized weighted mean difference (WMD) with 95% confidence intervals (CIs) were estimated for myocardial strain between DMD and healthy controls and a meta-analysis was conducted. Trial sequential analysis estimated whether the resulting evidence was sufficient.

Results

Eight studies with a total of 269 DMD children and 299 healthy participants were included. STE revealed that global longitudinal strain (GLS), global circumferential strain, average longitudinal strain (measured by two-dimensional STE at the apical four-chamber view), and average circumferential strain (measured by two-dimensional STE at the papillary muscle short-axis level) decreased (WMD = 4.17, 95% CI: 3.03–5.32; WMD = 3.98, 95% CI: 0.29–7.68; WMD = 4.18, 95% CI: 2.75–5.62; and WMD = 4.90, 95% CI: 2.38–7.43, respectively; all P < 0.05) compared with the controls and global radial strain was unchanged in the DMD group (WMD = − 4.33, 95% CI: − 9.53–0.87, P = 0.103). Trial sequential analysis indicated that available GLS samples were sufficient and confirmed that adequate evidence was accumulated. The credibility of other myocardial strains was questioned due to insufficiently involved studies.

Conclusion

GLS can be useful for early detection of left ventricle myocardial dysfunction in children with DMD.