Alterações da hemodinâmica vascular (rigidez e complacência) em pacientes diabéticos tipo 2 com e sem neuropatia autonômica cardiovascular

Abstract

Introduction. Cardiovascular Autonomic Neuropathy (CAN) is an important complication of Diabetes Mellitus (DM) and hypertension (AH), since its occurence is associated with worse prognosis and reduced quality of life, but even with high prevalence and important impact on cardiovascular morbidity and mortality; this clinical condition is underdiagnosed. Objective: To evaluate the relationship between two severe complications of type 2 Diabetes Mellitus - autonomic neuropathy and hemodynamic changes (arterial stiffness and compliance) using the Ewing's cardiovascular autonomic neuropathy assessment test, heart rate variability assessment, and vascular mechanics assessment (arterial stiffness). Casuistic and Methods: Eighty-one patients were divided into two groups, 1) patients with DM duration less than 10 years (DM Group<10 years - N=50); 2) patients with DM duration greater than 10 years (DM Group>10 years - N=31) submitted to the evaluation of autonomic function through heart rate variability and, vascular hemodynamics through pulse wave velocity (PWV), using the SphygmoCor device. Results: According to descriptive analysis, it was observed a higher prevalence of female gender and association of DM with other comorbidities such as dyslipidemia, smoking, alcoholism and sedentary lifestyle. Regarding the biochemical characteristics had no difference, except the analysis of albumin/creatinine ratio that in group 2 was positive, with a result of 54 mg/g (p=0.007). Analyzing the central hemodynamic characteristics: Central systolic arterial pressure, Augmentation Index (AI and AI 75%) and Pulse wave velocity, there was no statistical difference between groups (p=0.846, p=0.279, p=-0.554). In the evaluation of autonomic activity we found negative SNP index values in relation to the population mean for the same age group, that is 0.86 SD below the mean in the group DM < 10 years and 1.27 SD below the mean in the group DM > 10 years. However, the comparison of this parameter between the groups DM < 10 years versus DM > 10 years showed no statistical difference (p = 0.27). The SNS index values are increased compared to the population mean for the same age group, that is 1.64 SD above the mean in the group DM < 10 years and 2.86 SD above the in the group DM > 10 years. However the comparison of this parameter between groups DM < 10 years versus DM > 10 years showed no statistical difference (p = 0.22).Linear regression analysis between SNS index and blood pressure values recorded during ABPM in both groups showed low/moderate correlation indexes between increased sympathetic system activity and blood pressure values in the different monitoring periods, except for DBP that showed an important correlation between increased DBP in vigil and increased sympathetic tone (r = 0.45, p = 0.003). Conclusions: The results of this study have supported the presence of autonomic dysfunction in patients with type 2 diabetes mellitus with a history of diagnosis less than 10 or more than 10 years ago. The severity of dysfunction of the parasympathetic system and the sympathetic nervous system results from the time of exposure to the disease and glycemic uncontrol. Structural changes such as arterial stiffness and altered central hemodynamics did not correlate with changes in the performance of autonomic function in this study. However, this study, has showed significant elevation of the DBP at wakefulness recorded during ambulatory BP monitoring (ABPM), which may be associated to increased constant sympathetic activation. KeyWords: Cardiovascular Autonomic Neuropath