International Journal of Cardiovascular ResearchISSN: 2324-8602

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Research Article, Int J Cardiovas Res Vol: 6 Issue: 1

Right Ventricular Deformation in Asymptomatic Children with Type I Diabetes Mellitus

Mahmoud Soliman1*, Morad Beshay1, Rania El Zayat2 and Mohamed Abu el rous2
1Cardiology Department, Faculty of Medicine, Menoufia University, Egypt
2Pediatric Department, Faculty of Medicine, Menoufia University, Egypt
Corresponding Author : Mahmoud A Soliman, MD
Department of Cardiology, Faculty of Medicine, Menoufia University, Egypt
Tel: 01001600237
E-mail: [email protected]
Received: September 12, 2016 Accepted: December 18, 2016 Published: January 10, 2017
Citation: Soliman M, Beshay M, El Zayat R, Abu el rous M (2017) Right Ventricular Deformation in Asymptomatic Children with Type I Diabetes Mellitus. Int J Cardiovasc Res 6:1. doi: 10.4172/2324-8602.1000297

Abstract

Background: Right ventricular function in diabetic children was not fully addressed. Previous reports were mainly directed for the left ventricle. Our objective was to investigate the subclinical effects of diabetes on right ventricular systolic and diastolic function in asymptomatic children with type 1 D.M. using echocardiographic two dimensional strain and strain rate. Methods: This study was conducted on 45 children with type 1 DM and 20 apparently normal children with comparable age, sex and socioeconomic status as a control group. Each patient was subjected to history taking, physical examination, routine laboratory investigations and conventional echocardiographic examination. Apical four chamber view was used for offline analysis of RV deformation data including assessment of systolic strain (ε), peak systolic strain rate (SRs), peak early diastolic strain rate (SRe) and Peak late diastolic strain rate (SRa) obtained from the basal, mid and apical segments of the RV free wall. Results: Although conventional echocardiography failed to reveal any impairment in RV systolic performance (measured with Tricuspid Annular Plane Systolic Exercursion, TAPSE), the values of systolic strain and peak systolic strain rate in the basal, mid and apical segment of the RV free wall were significantly lower in DM group as compared with control group indicating impairment of RV systolic function. Similarly, decreased peak early diastolic strain rate in children with diabetes in RV free wall reflecting abnormalities of RV diastolic performance. Conclusion: Diabetes mellitus type 1 leads to RV systolic and diastolic dysfunction. Strain and strain rate imaging appear to be a sensitive tool for early detection such abnormalities.

Keywords: Right ventricular strain; Type 1 diabetes

Keywords

Right ventricular strain; Type 1 diabetes

Introduction

Diabetes mellitus leads to increased cardiovascular mortality that is evident in all age groups, particularly in children and adolescents with type I diabetes. This group of patients may be in need for specific cardiovascular risk estimation models [1]. Right ventricular function in diabetic children was not fully addressed. Previous reports were mainly directed for the left ventricle ignoring the role of the right ventricle. Right ventricular dysfunction has been recognized to be clinically and prognostically significant in various pathological settings, such as heart failure. This may be expected also in diabetes [2].
However, the assessment of right ventricular function remains difficult, because of the complex anatomy, non-uniform contraction and its retrosternal position. Strain/strain rate imaging provides extensive information about regional myocardial function which may be applicable to the right ventricle [3-7].

Methods

The present work prospectively included forty five consecutive children suffering from type 1 diabetes mellitus and twenty of apparently normal children with comparable age, sex and socioeconomic status as controls. Patients were collected from the Pediatric Endocrinology Clinic, Menoufia University Hospital in the period from October 2013 to March 2015. Control group were selected from general pediatric outpatient clinic in the same period.
Inclusion criteria
1. Children with type 1 diabetes mellitus under insulin therapy.
2. Age of onset of D.M. more than 2 years.
Exclusion criteria
1. Valvular and congenital heart disease.
2. Arrhythmias.
3. Impaired LV systolic function (EF<50%).
4. Pulmonary hypertension.
5. Patients with more than grade I tricuspid regurgitation.
6. Patients with poor quality of echocardiographic imaging.
7. Patients with chronic anemia e.g. Thalassemia.
8. Patients with hepatic or renal impairment.
Groups
The studied population was classified into two groups:
1. First group (patient group) consisted of 45 children with Type 1 DM.
2. Second group (control group) consisted of 20 apparently healthy children.
Investigations
Laboratory investigations: 1) Complete Blood Count 2) Hemoglobin A1c 3) Serum Creatinine, ALT & AST.
Echocardiographic and Doppler examination: Methodology of Echocardiographic and Doppler examination- Conventional echocardiographic Doppler examination as well as 2D- speckle tracking imaging was performed using commercially available system (Vivid 9 GE Vingmed Ultrasound AS, Horten, Norway) equipped with harmonic variable frequency (1.7-4) MHz phased array transducer and external work station for off line analysis. All patients were examined in left lateral position at end expiration. Multiple acoustic windows and imaging planes were used.
A. Two dimensional (2-D) and M-mode echocardiography: The patients were examined using the parasternal long axis and apical views. Linear measurements were made while cardiac anatomy was well visualized with 2-D echocardiography with ECG recording of the cardiac cycle. Chamber quantification was performed in accordance with the American Society of Echocardiography and the recommendations of the European Association of Cardiovascular Imaging [8,9].
i. Left ventricular measurements: were obtained at end-systole and end diastole in mm and include: Left ventricular internal diameter at end diastole (LVIDd), Left ventricular internal diameter at end systole (LVIDs), thickness of the interventricular septum in diastole (IVSd), thickness of the interventricular septum in systole (IVSs), thickness of the left ventricular posterior wall in diastole (LVPWd) and thickness of the left ventricular posterior wall in systole (LVPWs).
ii. Right ventricular measurements :
Right ventricular dimensions (RVD): Basal and mid cavitary dimensions were measured in apical four chamber view focusing on the right ventricle.
Tricuspid annular plane systolic excursion (TAPSE) was measured with M-mode in an apical four-chamber view, positioning the M- mode cursor on the lateral tricuspid annulus and aligning it as close as possible to the apex of the heart. Maximum plane systolic excursion of the lateral annulus is measured (the annular plane is identified on the M-mode recording as the first continuous line immediately below the RV cavity). The greater the descents of the base in systole, the better the RV systolic function.
B. Conventional Doppler echocardiography: The mitral and tricuspid diastolic flow tracing were imaged in the apical four chamber view by using pulsed Doppler echocardiography with sample volume sited at the tips of the mitral or tricuspid leaflets. Peak velocities of early (E) and late (A) filling were derived from atrioventricular valve inflow velocity profiles. The ratio of early to late peak velocities (E/A) was subsequently calculated.
C. Strain and strain rate: Two dimensional strain analysis was performed offline using the Echopac software (GE version1.8.X_ Vingmed). Myocardial strain and strain rate analysis included systolic strain (ε), peak systolic strain rate (SRs), peak early diastolic strain rate (SRe) and peak late diastolic strain rate (SRa) in the basal, mid and apical segment of RV free wall. Speckle-tracking derived 2D-strain images were obtained from apical 4-chamber view at 60-80 frame/ second.
To specify the RV end systole, the timing of pulmonary valve closure was derived from pulsed Doppler blood pool tracings recorded at end expiration to avoid marked respiratory variations. The timings of aortic and pulmonary valve closure were obtained from the heart cycle with the same R-R interval as the curve analyzed.
All myocardial deformation curves was averaged over three consecutive heart cycles for the right ventricle.

Statistical Analysis

The data were collected, tabulated, and analyzed by SPSS (statistical package for social science) version 17.0 on IBM compatible computer (SPSS Inc., Chicago, IL, USA).
T test was used for quantitative data and Mann Whitney test for non-uniform distributed data.
Chi-square test was used for qualitative data. Pearson’s Correlations were done whenever appropriate. P value<0.05 was considered significant

Results

There was no significant difference between diabetic patients and healthy controls regarding chronological age, sex distribution, anthropometric measurements, heart rate, systolic or diastolic blood pressure (Supplemental Tables 1 and 2)
As regards to left ventricle internal dimensions, and wall thickness, (Interventricular septal and LV posterior wall) in systole and diastole, fraction shorting and ejection fraction, there was no statistically significant difference between diabetic patients and healthy controls (Table 1).
Table 1: Comparison between studied groups as regards Echo (2-D and Mmode) parameters.
Also there was no statistically significant difference between both groups as regards to right ventricular dimensions (RVD) & Tricuspid annular plane systolic excursion (TAPSE)(27 ± 5.2 versus 26 ± 6.1, p value 0.12, 1.76 ± 0.13 versus 1.76 ± 0.12, p value 0.9 respectively) (Table 1).
Conventional pulsed wave Doppler revealed no significant differences in left ventricular diastolic filling patterns between diabetic patients and healthy controls. However there were significant differences in right ventricular diastolic filling patterns between patients with type 1 diabetes and healthy subjects (diabetics have had higher A wave velocity & lower E/A ratio compared with controls) (0.48 ± 0.13 versus 0.38 ± 0.12, p value 0.004, 1.37 ± 0.24 versus 1.73 ± 0.41, p value 0.001 respectively ) (Table 2).
Table 2: Comparison between studied groups as regards Mitral and Tricusped inflow parameters.
The present study revealed both systolic and diastolic RV dysfunction in asymptomatic patients with type 1 diabetes (Figure 1). Systolic strain (ε) (Table 3) and peak systolic strain rate (SRs) (Table 4), markers of regional contractile function, were both reduced in diabetics. Peak early diastolic strain rate (SRe) (Table 5) reflecting local relaxation of heart muscle, was also reduced.
Figure 1: RV strain rate indices in diabetic child.
Table 3: Comparison between studied groups as regards Strain (ε) in RV free wall segments.
Table 4: Comparison between studied groups as regards Systolic strain rate (SRs) in RV free wall segments.
Table 5: Comparison between studied groups as regards Peak early diastolic Strain rate (SRe) in RV free wall segments.
Also when we compare the mean of RV free wall ε, SRs and SRe between diabetic patients & controls (Table 6), we found statistically significant difference between both groups (-19.61 ± 11.09 Versus-34.28 ± 4.34, -1.5 ± 0.62 versus -2.19 ± 0.24, 1.87 ± 1.01 versus 3.1 ± 0.57, p value 0.001) (Table 7). There was no significant correlation in diabetic patients between RV strain/strain rate parameters and glycated hemoglobin (HbA1c) or the duration of diabetes in our study (Table 8).
Table 6: Comparison between studied groups as regards Peak late diastolic Strain rate (SRa) in RV free wall segments.
Table 7: Comparison between studied groups as regards RV free wall mean e, SRs, SRe and SRa.
Table 8: Correlation between lateral wall e, SRs, SRe and SRa and duration of DM and HbA1c in studied cases.

Discussion

Diabetes mellitus leads to functional and structural alterations in heart muscle. These changes attributed to disturbed carbohydrate and fat metabolism in cardiac myocytes resulting in hyperglycemia, hypertriglyceridemia, accumulation of toxic fatty acid intermediates, oxygen free radicals, damage of myofibrils and transverse tubules. Cardiomyocyte apoptosis, necrosis and fibrosis are also accused. Microangiopathy and autonomic neuropathy were proposed by some investigators [10-13]. The present study showed that right ventricular myocardial dysfunction occurs in asymptomatic patients with type 1 diabetes mellitus, and the impairment of RV function include both systolic and diastolic abnormalities. The strain/strain rate technique appears to be a sensitive tool for early detection of such abnormalities.
As regards TAPSE (used as a measure of RV systolic function) there was no significant difference between diabetic patients and healthy controls. TAPSE was correlated strongly with radionuclide angiography for evaluation of RV function, with low inter observer variability [14]. It has also been validated against biplane Simpson RV EF and RV fractional area shortening [15,16].
Our results were in agreement with Ilona et al. [17] who didn’t found significant difference between young patients with type 1 D.M. & healthy controls as regards RVD and TAPSE, however when the same patients were examined by 2D speckle tracking echocardiography RV systolic dysfunction in diabetic patients was identified (indicated by reduction in RV global and segmental “basal, mid and apical” longitudinal strain).
Conventional PW Doppler revealed significant differences in right ventricular diastolic filling patterns between patients with Type 1 diabetes and healthy subjects. This finding is consistent with Karamitsos et al. [18] study, where conventional Doppler revealed significant differences in right ventricular diastolic filling patterns.
Kosmala et al. [19] failed to show any significant differences with conventional Doppler in right ventricular diastolic filling patterns. This finding is inconsistent with our study, this discrepancy is most likely related to differences in study populations, since our patient cohort consisted of only type 1 diabetic patients [19].
The present study revealed both systolic and diastolic RV dysfunction in asymptomatic patients with type 1 diabetes. Systolic strain (ε) and peak systolic strain rate (SRs), markers of regional contractile function, were both reduced in diabetics. Peak early diastolic strain rate (SRe), reflecting local relaxation of heart muscle, was also reduced.
Left ventricular function in diabetics was extensively studied, on the contrary, RV function was less investigated.
Danielsen et al. [20] demonstrated subclinical LV systolic and diastolic abnormalities in a well-defined study population of persons younger than 50 years with long-term type 1 diabetes. The diastolic abnormalities were most prominent.
Boyer et al. [21] demonstrated that there are a significant percentage of asymptomatic, normotensive type 2 diabetics of patients with undiagnosed diastolic dysfunction.
Fang et al. [22] demonstrated that peak strain and strain rate were significantly reduced in patients with diabetes mellitus and that these changes were analogous to those associated with LVH which is recognized as an important cause of myocardial dysfunction.
Karamitsos et al. [18] demonstrated not only left ventricular but also right ventricular diastolic function is impaired in patients with type 1 diabetes mellitus and no evidence of coronary artery disease or hypertension using TDI.
Kosmala et al. [19] also demonstrated not only left ventricular but also right ventricular function is impaired in diabetic patients encompasses both systolic and diastolic abnormalities using strain imaging.
Parsaee et al. [23] studied patients with type II DM (without coronary artery disease or ejection fractions of less than 50%). They significantly lower RV systolic parameters and lower RV diastolic parameters.
Consistent with the findings of the present study, Gaber et al. [24] assessed patients with type II DM and reported RV systolic and diastolic dysfunctions using three dimensional strain imaging (systolic strain, SRs, and SRe in both RV basal and apical segments).
In the present study, there were no any significant correlations between the duration of diabetes and the severity of RV dysfunction, which is consistent with the findings of Kosmala et al. [19]. In Regard to left ventricule, Danielsen et al. found no relations between duration of diabetes, degree of retinopathy or metabolic control and any of the other variables of systolic or diastolic LV function [20].
Vinereanu et al. [25] study demonstrated an association of HbA1c with estimates of LV dysfunction. Fang et al. [22] found no correlation between Indices of diabetic control (HbA1c or blood glucose) and left ventricular myocardial function.

Limitations of the Study

First, the small sample size may have an impact on our results, second, the standards values of strain and strain rate indices in this age group needs further validation.

Conclusion

From the results of this study, it was concluded that:
• Diabetes mellitus type 1 leads to RV systolic and diastolic dysfunction.
• Strain and strain rate imaging appear to be a sensitive tool for early detection such abnormalities
• No significant correlation can be found between duration of diabetes or the degree of glycemic control and echocardiographic parameters of RV ventricular functions.

Ethical Considerations

All parents of children gave informed written consent to participate in this study.

References

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