ABC | Volume 110, Nº2, February 2018

Original Article Autonomic and Vascular Control in Prehypertensive Subjects with a Family History of Arterial Hypertension Josária Ferraz Amaral, 1 Diana de Medeiros Andrade Borsato, 1 Isabelle Magalhães Guedes Freitas, 1 Edgar Toschi-Dias, 2 Daniel Godoy Martinez, 1 Mateus Camaroti Laterza 1 Universidade Federal de Juiz de Fora (UFJF), 1 Juiz de Fora, MG; Instituto do Coração (InCor) - Faculdade de Medicina da Universidade de São Paulo, 2 São Paulo, SP – Brazil Mailing Address: Josária Ferraz Amaral • Universidade Federal de Juiz de Fora - Faculdade de Educação Física e Desportos. Campus Universitário, S/N. CEP 36036-900, Martelos, Juiz de Fora, MG – Brasil. E-mail: josaria_ferraz@hotmail.com Manuscript received June 15/06/2017, revised manuscript September 18, 2017, accepted September 27, 2017 DOI: 10.5935/abc.20180006 Abstract Background: Individuals with a family history of systemic arterial hypertension (FHSAH) and / or prehypertension have a higher risk of developing this pathology. Objective: To evaluate the autonomic and vascular functions of prehypertensive patients with FHSAH. Methods: Twenty-five young volunteers with FHSAH, 14 normotensive and 11 prehypertensive subjects were submitted to vascular function evaluation by forearm vascular conductance(VC) during resting and reactive hyperemia (Hokanson®) and cardiac and peripheral autonomic modulation, quantified, respectively, by spectral analysis of heart rate (ECG) and systolic blood pressure (SBP) (FinometerPRO®). The transfer function analysis was used to measure the gain and response time of baroreflex. The statistical significance adopted was p ≤ 0.05. Results: Pre-hypertensive individuals, in relation to normotensive individuals, have higher VC both at rest (3.48 ± 1.26 vs. 2.67 ± 0.72 units, p = 0.05) and peak reactive hyperemia (25, 02 ± 8.18 vs. 18.66 ± 6.07 units, p = 0.04). The indices of cardiac autonomic modulation were similar between the groups. However, in the peripheral autonomic modulation, greater variability was observed in prehypertensive patients compared to normotensive individuals (9.4 [4.9-12.7] vs. 18.3 [14.8‑26.7] mmHg²; p < 0.01) and higher spectral components of very low (6.9 [2.0-11.1] vs. 13.5 [10.7-22.4] mmHg², p = 0.01) and low frequencies (1.7 [1.0-3.0] vs. 3.0 [2.0-4.0] mmHg², p = 0.04) of SBP. Additionally, we observed a lower gain of baroreflex control in prehypertensive patients compared to normotensive patients (12.16 ± 4.18 vs. 18.23 ± 7.11 ms/mmHg, p = 0.03), but similar delay time (-1.55 ± 0.66 vs. -1.58 ± 0.72 s, p = 0.90). Conclusion: Prehypertensive patients with FHSAH have autonomic dysfunction and increased vascular conductance when compared to normotensive patients with the same risk factor. (Arq Bras Cardiol. 2018; 110(2):166-174) Keywords: Hypertension / genetic; Autonomic Nervous System; Risk Factors; Endothelium, Vascular / physiopathology. Introduction Primary prevention has been recommended for individuals at increased risk for developing systemic arterial hypertension (SAH). Among them, individuals with a family history of SAH (FHSAH) 1,2 and / or prehypertension 3 stand out. The reason for the increased susceptibility of hypertensive offspring to developing hypertension is not completely elucidated. However, studies indicate that autonomic abnormalities, such as increased sympathetic modulation, 4 reduction of heart rate variability 4 and reduction of baroreflex sensitivity 5 are among the changes that may contribute to the onset of hypertension in normotensive children of hypertensive individuals. In addition, vascular abnormalities have also been considered as potential candidates for the onset of hypertension in this population. 6,7 In prehypertensive patients, similar to those with FHSAH, dysfunctions 8,9 and autonomic and vascular 10 have also been pointed out as the main etiological factors of pressure elevation. Although prehypertension has a strong genetic predisposition, 11,12 the pathophysiological mechanisms responsible for pressure elevation in individuals with both risk factors, namely prehypertension and FHSAH, are not yet known. Therefore, this study aimed to evaluate the autonomic and vascular functions of prehypertensive individuals with FHSAH. Methods Sample From the sample calculation performed based on the difference in sympathetic cardiac modulation of 0.31 ms² between the means of the normotensive and prehypertensive 166