Evaluation of cardiac function through biochemical indices and tissue doppler echocardiography in children and adolescents with diabetes mellitus type 1

OBJECTIVE: Evaluating cardiac function through conventional Doppler echocardiography, tissue Doppler echocardiography and subclinical risk factors in children and adolescents with diabetes mellitus type I followed in outpatient clinic of Pediatric Endocrinology and Metabolism department of Medical Faculty of Celal Bayar University.METHODS: A total of 88 children and adolescents (42 girls and 46 boys) between 5 and 25 years old followed in outpatient clinic of Pediatric Endocrinology and Metabolism Department were included in the present study. Based on duration of diabetes mellitus, the patients were divided into three groups as 0-60 months (Group 1), 61-120 months (Group 2) and 121 months and above (Group 3). All patients underwent measurements of high-density lipoprotein (HDL), low-density lipoprotein (LDL), triglyceride (TG), total cholesterol (TC), HbA1c, asymmetrical dimethyl arginine (ADMA), lipoprotein associated phospholipase A2 (Lp-PLA2) in the serum samples and carotid artery intima-media thickness (IMT) was evaluated for presence of atherosclerosis in all patients using color Doppler ultrasoundography. Levels of microalbuminuria were measured in 24 urine samples. Cardiac function of the patients were examined using conventional Doppler echocardiography and tissue Doppler echocardiography along with serum level of troponine I for possible cardiac damage.FINDINGS: Mean age was 125.53 ± 41.60 months, 186.26 ± 48.45 months, and233.96 ± 48.11 months for the Groups 1, 2 and 3, respectively. When the three groups were compared in terms of anthropometrical characteristics, no statistically significant difference was found in weight SD and BMI SD among them. BMI, length SD and weight adjusted for length showed statistically significant differences between the groups (P = 0.000, P = 0.007, and P = 0.002, respectively). Significant differences were found in systolic blood pressure (SBP) and diastolic blood pressure (DBP) among the three groups (P = 0.003, P = 0.008, respectively). When the groups of patients were compared, no significant differences were found in urinary level of microalbuminuria and serum levels of troponine I, HDL-C and HbA1c whereas significant differences were found in serum levels of TC, LDL-C, TG, ADMA, and Lp-PLA2. Levels of ADMA were found to be significantly higher in Group 1 than in other groups (P = 0.006). Level of Lp-PLA2 was found to be significantly lower in Group 1 than in Group 2 (P = 0.030) but it was not significantly different between the Groups 1 and 3 and between the Groups 2 and 3 (P > 0.05). In regard to carotid artery IMT, significant difference was found between the groups which was obvious for the right side and borderline for the left side (P = 0.025, P = 0.05, respectively). In evaluations of pulse wave Doppler and tissue Doppler echocardiography early diastolic wave velocity (E m/sec), late diastolic wave velocity (A m/sec), systolic wave velocity (S m/sec), IVRT (isovolumetric relaxation time), IVCT (isovolumetric contraction time) were not significantly different between the groups (P > 0.05). E/A ratio of pulse wave Doppler echocardiography was statistically significantly different between each 3 groups whereas Em/Am ratio of tissue Doppler echocardiography was not. When LVAD and IVS values of 3 groups were compared statistically significant difference was found. LVAD and IVS values were found to be significantly higher in the Groups 2 and 3 than in the Group 1 (P = 0.002, P = 0.001, respectively). A moderate correlation was found between duration of diabetes and E/A ratio of pulse wave Doppler echocardiography and a weak negative one between Em/Am ratio of tissue Doppler echocardiography. A moderate negative correlation between ADMA levels and duration of diabetes and a weak negative correlation between ADMA and Lp-PLA2 levels were found when the patients in 3 groups were evaluated.CONCLUSION: Serum levels of Lp-PLA2 increased with duration of diabetes in the children and adolescents with diabetes mellitus type 1. This was considered as an early indicator of atherosclerosis. However, ADMA levels specified as a risk factor for atherosclerosis in many studies were not found to be associated to endothelial dysfunction in the present study and not considered as an marker of cardiovascular risk. Carotid arterial IMT increasing with duration of the diabetes may be considered as a risk factor for cardiovascular diseases. In evaluation of left cardiac function by means of pulse wave Doppler echocardiography, statistically significant differences were found between the groups whereas there was no significant difference in tissue Doppler echocardiography. This was attributed to the fact that the measurements were made through a single annulus and that the study was compared between the groups in a cross-sectional manner. Nevertheless, the fact that Em/Am ratio of tissue Doppler echocardiography decreased with duration of diabetes supports the view that tissue Doppler echocardiography is valuable in diagnosing diastolic dysfunction.Key words: Diabetes mellitus type I, tissue Doppler echocardiography, biochemical parameters.