Relação entre testes autonômicos cardiovasculares, achados ecocardiográficos e marcadores glicêmicos no Diabetes Mellitus tipo 2

Abstract

Introduction: Diabetes mellitus is a metabolic disease recognized worldwide as a public health emergency. Chronic hyperglycemia, the main cause of the disease, can lead to vascular and autonomic complications, including cardiovascular autonomic neuropathy (CAN). This complication is directly linked to the duration of the disease and the control of glycemic levels. Cardiovascular autonomic tests are essential to diagnose CAN, through stimuli that alter heart rate and blood pressure. The presence of NAC can affect cardiac function, even leading to heart failure and increasing morbidity and mortality. Echocardiography is a technique used to evaluate cardiac function, allowing the identification of various changes. Patients with type 2 diabetes mellitus (DM2) may present relationships between cardiovascular autonomic tests and glycemic control, highlighting the importance of cardiac monitoring in this group of patients. Objective: To evaluate the relationship between cardiovascular autonomic tests, ventricular function (systolic and diastolic) and markers of glycemic control in individuals with type 2 diabetes mellitus with and without cardiovascular autonomic neuropathy, and, in addition, to analyze the possible influence of glycemic control on these responses. Methods: 62 individuals (36 men and 26 women) with DM2, aged between 40 and 65 years and BMI 29±4, were evaluated, divided into 4 groups: a) without NAC CG (with glycemic control); b) without NAC SCG (without glycemic control); c) NAC CG and d) NAC SCG. The R-R intervals (iRR) of the electrocardiographic signals, obtained from the MC5 derivation, were captured by the BioAMP and the respiratory signals by a respiratory belt. The echocardiographic variables of systolic and diastolic function were evaluated by two-dimensional mode.Blood tests and three cardiovascular autonomic tests were also performed, which evaluated the response of heart rate (HR) and systolic blood pressure (SBP) to postural change stimuli. active (MPA), maneuver to accentuate respiratory sinus arrhythmia - MASR (Expiration/Inspiration), ratio 30:15, and Valsalva maneuver (MV), which also evaluates the contribution of the cardiac parasympathetic nervous system. Results: The main findings were evident positives between E/A ratio and 30:15 (r=0.848), in the NAC CG group, respectively; and negative between HbA1c and left ventricular diastolic diameter in the group without NAC CG (r=-0.727), between MASR and HbA1c in the NAC CG group (r=-0.939) and NAC without CG (r=-0.531). Conclusion: Individuals with CAN obtained lower values in the indices of cardiovascular autonomic tests, with lack of glycemic control being a factor that contributes to worse results. The relationship between the E/A ratio indices and the HR response to postural changes in the group with NAC CG suggests a relationship between echocardiographic findings and responses to autonomic tests, but more studies are needed to be able to define these findings as markers of LV diastolic dysfunction.