In-Depth Insight Into the Mechanisms of Cardiac Dysfunction in Patients With Type 1 Diabetes Mellitus Using Layer-Specific Strain Analysis

Assessment of left ventricular systolic function and pathological changes using layer-specific strain in rats with myocardial hypertrophy at various disease stages

PURPOSE

Although layer-specific strains are effective for assessing cardiac function, their application in rat models at different stages of myocardial hypertrophy (MH) is immature, and their relationship with MH and myocardial fibrosis (MF) is unclear. This study aimed to investigate changes in layer-specific strains across different disease stages and analyze their association with pathological changes.

METHODS

A progressive MH rat model was established using isoproterenol injection and categorized into baseline, 1-week, 2-week, 3-week, and 4-week groups. Echocardiographic indices and pathological differences between the five groups were assessed. The correlation between layer-specific strain parameters and cardiomyocyte hypertrophy and MF was analyzed.

RESULTS

As the disease progressed, the left ventricular (LV) dilated, with the LV wall thickening and then thinning. The left ventricular ejection fraction declined significantly in the fourth week. The endo-myocardial, mid-myocardium and epi-myocardial global longitudinal strain, along with endo-myocardial global circumferential strain (GCS) and the transmural gradient, significantly decreased in the first week, the mid-myocardium GCS in the second week, and continued to decrease as the disease progressed. The epi-myocardial GCS increased in the first week, but then decreased, becoming significantly lower than the baseline group in the third week. The degrees of MH and MF were correlated with the layer-specific strain parameters.

CONCLUSION

Layer-specific strains maybe are valuable for early and effective monitoring of LV systolic function and pathological changes in rats with MH. Longitudinal strain is more sensitive to functional changes; endomyocardial strain reflects early LV remodeling and circumferential strain perhaps indicates disease progression and severity.

Assessment of anthracycline-induced cardiotoxicity in childhood cancer survivors during long-term follow-up using strain analysis and intraventricular pressure gradient measurements

BACKGROUND

Cardiac dysfunction due to cardiotoxicity from anthracycline chemotherapy is a leading cause of morbidity and mortality in childhood cancer survivors (CCS), and the cumulative incidence of cardiac events has continued to increase. This study identifies an adequate indicator of cardiac dysfunction during long-term follow-up.

PROCEDURE

In total, 116 patients (median age: 15.5 [range: 4.7-40.2] years) with childhood cancer who were treated with anthracycline were divided into three age groups for analysis (C1: 4-12 years of age, C2: 13-18 years of age, C3: 19-40 years of age), and 116 control patients of similar ages were divided into three corresponding groups (N1, N2, and N3). Layer-specific strains were assessed for longitudinal strain (LS) and circumferential strain (CS). The total and segmental intraventricular pressure gradients (IVPG) were also calculated based on Doppler imaging of the mitral inflow using Euler's equation.

RESULTS

Conventional echocardiographic parameters were not significantly different between the patients and controls. All layers of the LS and inner and middle layers of the basal and papillary CS in all ages and all IVPGs in C2 and C3 decreased compared to those of corresponding age groups. Interestingly, basal CS and basal IVPG in CCS showed moderate correlation and both tended to rapidly decrease with aging. Furthermore, basal IVPG and anthracycline dose showed significant correlations.

CONCLUSIONS

Basal CS and total and basal IVPGs may be particularly useful indicators of cardiotoxicity in long-term follow-up.

Novel Findings of Early Cardiac Dysfunction in Patients With Childhood-Onset Inflammatory Bowel Disease Using Layer-Specific Strain Analysis

BACKGROUND

Patients with inflammatory bowel disease (IBD) are at a higher risk of developing cardiovascular diseases than healthy individuals, owing to persistent chronic inflammation and treatment effects. This study aimed to assess left ventricular function in patients with childhood-onset IBD using layer-specific strain analysis and to identify early indicators of cardiac dysfunction in them.

METHODS

A total of 47 patients with childhood-onset ulcerative colitis (UC), 20 patients with Crohn's disease (CD), and 75 age- and sex-matched healthy control subjects were included in this study. Conventional echocardiographic measurements of layer-specific (ie, endocardium, midmyocardium, and epicardium) global longitudinal strain and global circumferential strain (GCS) were evaluated in these participants.

RESULTS

Layer-specific strain analysis showed that global longitudinal strain was lower in all layers for the UC (P < .001) and CD (P < .001) groups, regardless of the age at onset, but that GCS was only lower in the midmyocardial (P = .032) and epicardial (P = .018) layers in the CD group than in the control group. Although the mean left ventricular wall thickness was not significantly different among the groups, it was significantly correlated with the GCS of the endocardial layer in the CD group (ρ= -0.615; P = .004), suggesting that thickening of the left ventricular wall occurred as a compensatory mechanism to maintain the endocardial strain in the CD group layer.

CONCLUSIONS

Children and young adults with childhood-onset IBD displayed decreased midmyocardial deformation. Layer-specific strain could also be useful to identify indicators of cardiac dysfunction in patients with IBD.

Non-Invasive Assessment of the Intraventricular Pressure Using Novel Color M-Mode Echocardiography in Animal Studies: Current Status and Future Perspectives in Veterinary Medicine

The assessment of diastolic function has received great interest in order to comprehend its crucial role in the pathophysiology of heart failure and for the early identification of cardiac events. Silent changes in the intraventricular flow (IVF) dynamics occur before the deterioration of the cardiac wall, although they cannot be detected using conventional echocardiography. Collective information on left ventricular (LV) pressures throughout the cardiac cycle has great value when dealing with patients with altered hemodynamics. Accurate pressure measurement inside the ventricle can be obtained by invasive methods to determine the LV diastolic pressures, which reflect the myocardial relaxation and compliance. However, catheterization is only feasible in the laboratory setting and is not suitable for clinical use due to its disadvantages. In contrast, echocardiography is simple, safe, and accessible. Color M-mode echocardiography (CMME) is an advanced cardiac evaluation technique that can measure the intraventricular pressure differences (IVPDs) and intraventricular pressure gradients (IVPGs) based on the Doppler shift of the IVF. Recently, the assessment of IVPD and IVPG has gained growing interest in the cardiovascular literature in both animal and human studies as a non-invasive method for the early diagnosis of cardiac dysfunctions, especially diastolic ones. The usability of IVPD and IVPG has been reported in various surgically induced heart failure or pharmacologically altered cardiac functions in rats, dogs, cats, and goats. This report aims to give an overview of the current studies of CMME-derived IVPD and IVPG in animal studies and its feasibility for clinical application in veterinary practice and to provide the prospects of the technique's ability to improve our understanding.

Diabetic cardiomyopathy: Clinical phenotype and practice

Diabetic cardiomyopathy (DCM) is a pathophysiological condition of cardiac structure and function changes in diabetic patients without coronary artery disease, hypertension, and other types of heart diseases. DCM is not uncommon in people with diabetes, which increases the risk of heart failure. However, the treatment is scarce, and the prognosis is poor. Since 1972, one clinical study after another on DCM has been conducted. However, the complex phenotype of DCM still has not been fully revealed. This dilemma hinders the pace of understanding the essence of DCM and makes it difficult to carry out penetrating clinical or basic research. This review summarizes the literature on DCM over the last 40 years and discusses the overall perspective of DCM, phase of progression, potential clinical indicators, diagnostic and screening criteria, and related randomized controlled trials to understand DCM better.

Left Ventricular Measurements and Strain in Pediatric Patients Evaluated for Systemic Hypertension and the Effect of Adequate Anti-hypertensive Treatment

Pediatric hypertension (HTN) is an epidemic that is associated with HTN in adulthood and adverse cardiovascular outcomes. We hypothesized that children with HTN would have left ventricular (LV) hypertrophy and abnormal LV global longitudinal strain (GLS) on echocardiogram and that these values would differ by weight, race, and HTN treatment. Data were collected from first visits to the HTN Program from 12/2011 to 9/2018, excluding patients with cardiac disease or heart transplantation. LV measurements including LV mass index (LVMI), LV GLS, and diastolic indices were compared between groups. Multivariable logistic regression was used to identify risk factors for an abnormal LVMI. There were 212 patients with an interquartile age range of 13-18 years. On univariate analysis, LVMI was higher in hypertensive, obese, and African American patients. LV strain was less negative in obese and African American patients. Adequately treated patients with HTN had a higher LVMI and a higher E/e' ratio compared to patients with no HTN. On multivariate analysis, only obesity was associated with an LVMI ≥ 95th percentile (OR 2.9, 95% CI 1.4, 5.8). LVMI is higher in hypertensive, obese, and African American patients; however, in the multivariate analysis, obesity was the only independent risk factor for an abnormal LVMI. LVMI was still higher in those adequately treated for HTN compared to patients without HTN, possibly due to concomitant obesity. Future studies should focus on subclinical changes in LV performance seen in obese and hypertensive patients and the impact on long-term health.

Heart Failure in Type 1 Diabetes: A Complication of Concern? A Narrative Review

Heart failure (HF) has been a hot topic in diabetology in the last few years, mainly due to the central role of sodium-glucose cotransporter 2 inhibitors (iSGLT2) in the prevention and treatment of cardiovascular disease and heart failure. It is well known that HF is a common complication in diabetes. However, most of the knowledge about it and the evidence of cardiovascular safety trials with antidiabetic drugs refer to type 2 diabetes (T2D). The epidemiology, etiology, and pathophysiology of HF in type 1 diabetes (T1D) is still not well studied, though there are emerging data about it since life expectancy for T1D has increased in the last decades and there are more elderly patients with T1D. The association of T1D and HF confers a worse prognosis than in T2D, thus it is important to investigate the characteristics, risk factors, and pathophysiology of this disease in order to effectively design prevention strategies and therapeutic tools.

The MEK inhibitor U0126 ameliorates diabetic cardiomyopathy by restricting XBP1's phosphorylation dependent SUMOylation

Background: Chronic diabetes accelerates vascular dysfunction often resulting in cardiomyopathy but underlying mechanisms remain unclear. Recent studies have shown that the deregulated unfolded protein response (UPR) dependent on highly conserved IRE1α-spliced X-box- binding protein (XBP1s) and the resulting endoplasmic reticulum stress (ER-Stress) plays a crucial role in the occurrence and development of diabetic cardiomyopathy (DCM). In the present study, we determined whether targeting MAPK/ERK pathway using MEK inhibitor U0126 could ameliorate DCM by regulating IRE1α-XBP1s pathway.

Method: Three groups of 8-week-old C57/BL6J mice were studied: one group received saline injection as control (n=8) and two groups were made diabetic by streptozotocin (STZ) (n=10 each). 18 weeks after STZ injection and stable hyperglycemia, one group had saline treatment while the second group was treated with U0126 (1mg/kg/day), 8 weeks later, all groups were sacrificed. Cardiac function/histopathological changes were determined by echocardiogram examination, Millar catheter system, hematoxylin-eosin staining and western blot analysis. H9C2 cardiomyocytes were employed for in vitro studies.

Results: Echocardiographic, hemodynamic and histological data showed overt myocardial hypertrophy and worsened cardiac function in diabetic mice. Chronic diabetic milieu enhanced SUMOylation and impaired nuclear translocation of XBP1s. Intriguingly, U0126 treatment significantly ameliorated progression of DCM, and this protective effect was achieved through enriching XBP1s' nuclear accumulation. Mechanistically, U0126 inhibited XBP1s' phosphorylation on S348 and SUMOylation on K276 promoting XBP1s' nuclear translocation. Collectively, these results identify that MEK inhibition restores XBP1s-dependent UPR and protects against diabetes-induced cardiac remodeling.

Conclusion: The current study identifies previously unknown function of MEK/ERK pathway in regulation of ER-stress in DCM. U0126 could be a therapeutic target for the treatment of DCM.

Discrepancy of Aortic Valve Area Measurements by Doppler vs. Biplane Stroke Volume Measurements and Utility of Combining the Different Areas in Aortic Valve Stenosis - The Asian Valve Registry

BACKGROUND

The aortic valve area index (AVAI) in aortic stenosis (AS) is measured by echocardiography with a continuity equation using the stroke volume index by Doppler (SVIDoppler) or biplane Simpson (SVIBiplane) method. AVAIDopplerand AVAIBiplaneoften show discrepancy due to differences between SVIDopplerand SVIBiplane. The degree of discrepancy and utility of combined AVAIs have not been investigated in a large population of AS patients, and the characteristics of subjects with larger discrepancies are unknown.

METHODS AND RESULTS

We studied 820 patients with significant AS (AVADoppler<1.5 cm2) enrolled in the Asian Valve Registry, a prospective multicenter registry at 12 Asian centers. All-cause death and aortic valve replacement were defined as events. SVIDopplerwas significantly larger than SVIBiplane(49±11 vs. 39±11 mL/m2, P<0.01) and AVAIDopplerwas larger than AVAIBiplane(0.51±0.15 vs. 0.41±0.14 cm2/m2, P<0.01). An increase in (AVAIDoppler- AVAIBiplane) correlated with shorter height, lower weight, older age, smaller left ventricular (LV) diameter and increased velocity of ejection flow at the LV outflow tract. Severe AS by AVAIDoppleror AVAIBiplaneenabled prediction of events, and combining these AVAIs improved the predictive value of each.

CONCLUSIONS

Discrepancy in AVAI by Doppler vs. biplane method was significantly more pronounced with increased LV outflow tract flow velocity, shorter height, lower weight, older age and smaller LV cavity dimensions. Combining the AVAIs enabled mutual and incremental value in predicting events.

Assessment of subclinical diabetic cardiomyopathy by speckle-tracking imaging

BACKGROUND

Diastolic dysfunction is traditionally believed to be the first subclinical manifestation of diabetic cardiomyopathy (DCM), leading to systolic dysfunction and then overt heart failure. However, in the last few years, several studies suggested that systolic subclinical dysfunction measured by speckle-tracking echocardiography (STE) may appear ahead of diastolic dysfunction. In this review, the main endpoint is to show whether subclinical myocardial systolic dysfunction appears ahead of diastolic dysfunction and the implication this may have on the evolution and management of DCM.

MATERIALS AND METHODS

We performed a search in PubMed for all relevant publications on the assessment of DCM by STE from 1 June 2015 to 1 June 2020.

RESULTS AND CONCLUSIONS

The results illustrate that subclinical systolic dysfunction assessed by STE is present in early DCM stages, with or without the association of diastolic dysfunction. This could be a promising perspective for the early management of patients with DCM leading to the prevention of the overt form of disease.

Left atrial dysfunction and stiffness in pediatric and adult patients with Type 1 diabetes mellitus assessed with speckle tracking echocardiography

BACKGROUND

Subclinical diastolic dysfunction in patients with Type 1 diabetes mellitus (T1DM) caused by myocardial injury due to diabetic cardiomyopathy leads to a high risk of death and heart failure. This myocardial injury extends not only to the left ventricle (LV) but also to the left atrium (LA). However, LA function in children and young adults with T1DM has not been extensively studied.

OBJECTIVE

Therefore, the aim of this study was to assess LA dysfunction in pediatric and adult patients with T1DM using LA strain analysis with echocardiography.

SUBJECTS

Fifty-three patients (median age: 23 [range: 5-41] years) with T1DM.

METHODS

We divided the patients into three age groups (D1: 5-14 years, D2: 15-24 years, D3: 25-41 years); 53 age- and sex-matched controls were divided into three corresponding groups (C1, C2, and C3). LA and LV functions were evaluated using echocardiography.

RESULTS

LA reservoir strain was lower in the D2 and D3 groups than in the C2 and C3 groups (P = 0.001, P = 0.004, respectively). LA conduit strain was lower in the D2 group than in the C2 group (P = 0.002). LA stiffness was significantly greater in the D3 group than in the C3 group (P < 0.001).

CONCLUSIONS

In patients with T1DM, LA phasic function decreased in adolescents and young adults, and LA stiffness increased in adult patients aged >30 years. LA phasic function and LA stiffness can be potentially used as early markers for diastolic dysfunction.

Echocardiographic parameters according to insulin dose in young patients affected by type 1 diabetes

Insulin dose has been found to associate to several cardiometabolic risk factors in type 1 diabetes. Changes over time in body weight and composition may partly explain this association. However, no data are available on the relationship between insulin dose and echocardiographic parameters of both systolic and diastolic function in type 1 diabetes. Therefore, the aim of the present study was to examine systolic and diastolic echocardiographic parameters in relation to insulin dose in young patients with type 1 diabetes. The study was carried out on 93 consecutive outpatients with type 1 diabetes with a mean age of 32.8 ± 9.8 years. All patients were examined with a transthoracic echocardiography. Clinical and laboratory data were collected. The median value of daily insulin dose was used to categorized patients in two groups: high and low insulin dose group. Patients belonging to the high insulin dose group showed higher levels of cardiometabolic risk factors such as BMI, triglycerides and TG/HDL cholesterol ratio. Indexes of both systolic and diastolic function were similar in both groups except isovolumetric relaxation time (IVRT), that was significantly prolonged in patients of the high insulin group (94.4 ± 15.0 vs 86.7 ± 13.1 ms, p = 0.008). In the multivariate regression analysis, insulin dose was positively and significantly associated with IVRT. In this study we report an association between insulin dose and impaired active diastolic myocardial relaxation. Future studies are needed to further explore this observation.

Echocardiography, an Indispensable Tool for the Management of Diabetics, with or without Coronary Artery Disease, in Clinical Practice

Diabetes mellitus is a major factor contributing to the development of cardiovascular disease. As morbidity and mortality rates rise dramatically, when target organ damage develops pre-symptomatic assessment is critical for the management of diabetic patients. Echocardiography is a noninvasive and reproducible method that may aid in risk stratification and in evaluation of treatment effects. The aim of this review is to analyze the echocardiographic techniques which can detect early alteration in cardiac function in patients with diabetes.

Does layer-specific strain using speckle tracking echocardiography improve the assessment of left ventricular myocardial deformation? A review

An increasing number of studies of left ventricular myocardial deformation have been published. Layer-specific strain using speckle tracking echocardiography to evaluate left ventricular function is not recommended in clinical practice. However, evaluation of myocardial mechanics using longitudinal and circumferential layer-specific strain enables the detection of subclinical impairment of myocardial deformation in various diseases. Unfortunately, normal values for longitudinal and circumferential strain have not been clearly defined. In normal subjects, layer-specific strain decreases from the endocardial to the epicardial layer, and from the apex to the base of the left ventricle. Although various studies have tried to define normal values for each layer in healthy subjects, studies with more subjects are needed. This tool has good reproducibility in terms of intraobserver and interobserver variability, but, as with monolayer strain, it has poor intervendor variability. Efforts that aim for standardization between vendors will be required before widespread use of this technique can be advocated.