ABC | Volume 114, Nº4, April 2020

Original Article Linhares et al. Hydrotherapy reduces arterial stiffness in pregnant women Arq Bras Cardiol. 2020; 114(4):647-654 In this study, we evaluated the acute effects of a standardized hydrotherapy session on AS parameters, such as AIx, in pregnant women with CH compared with a group of women with normal pregnancy. The analysis also included the heart rate (HR), systolic (SBP) and diastolic (DBP) BPs, mean BP (MBP), and peripheral (brachial artery) and central (aorta) pulse pressures (PPs). Methods Cross-sectional, controlled study conducted at the Aquatic Physical Therapy Clinic in Belo Horizonte (Minas Gerais, Brazil) from July 2015 to July 2016. The evaluation included 36 pregnant women, of whom 12 had chronic hypertension (thus considered to be at high risk) who were included in a hypertensive group (HG) and 24 normal-risk pregnant women who were included in a control group (CG). The diagnosis of hypertension during pregnancy was confirmed according to the 7 th Brazilian Hypertension Guideline. 18 The study included high‑risk and normal-risk pregnant women receiving prenatal care at Santa Casa de Belo Horizonte (MG), aged between 18 and 40 years, with a gestational age of 24 to 34 weeks, and with medical approval to perform aquatic activities, who were consecutively invited to participate in the research. Cases of multiple-gestation pregnancies, pregnant women who presented bleeding in the first and second pregnancy trimesters, smokers, and those with skin lesions or any condition that could be aggravated by immersion in heated water were excluded. The study was approved by the Research Ethics Committee of Faculdade Ciências Médicas de Minas Gerais, Brasil, (CEPCM‑MG), under the opinion number 35487814.1.0000.5134. All pregnant women enrolled agreed to participate in the study and signed a free and informed consent form. For participation in the study, the group of pregnant women with hypertension should not interrupt or modify their pharmacological treatment, when previously prescribed, and during the research, these participants were encouraged to follow their health care recommendations. Evaluation protocol Initially, general data of the participants were collected, including age, gestational age, anthropometric measurements, personal medical history (clinical history of hypertension, diabetes mellitus, heart disease, chronic kidney disease, allergies, epilepsy), as well as information about exercise practice during pregnancy and medications in use. Vital signs of each participant were measured with the deviceMobil-O-Graph®NG (IEM, Stolberg, Germany) before the participant was referred to the hydrotherapy session. After the session, clinical and hemodynamic parameters were measured once again. Evaluation of blood pressure and arterial stiffness Measurements of bBP, central blood pressure (cBP), and AS parameters were performed noninvasively using the Mobil-O-Graph® NG device (IEM, Stolberg, Germany) with the inbuilt ARC Solver algorithm (the ARC Solver Method, Austrian Institute of Technology). This device is an oscillometric monitor for ambulatory bBP measurement approved by the US Food and Drug Administration and the European Conformité Européenne , whose BP and AS detection unit has been validated by the British Hypertension Society and the American Heart Association’s Council on Hypertension. 19-22 After measuring the upper limb perimeter and choosing the right cuff, measurements were carried out according to recommendations of the 7 th Brazilian Guideline on Hypertension. 23 Three consecutive automated measurements were obtained, and the results were expressed as the average of the obtained values. AS was estimated by the variables AIx adjusted to a HR of 75 bpm (AIx@75) and pulse wave velocity (PWV). The equipment also provided measurements of HR, SBP, DBP, MBP, and peripheral and central PP. Hydrotherapy session Pregnant women from both groups, HG and CG, underwent standardized hydrotherapy sessions in a heated indoor pool with temperature between 32 and 34°C and duration of 40 minutes, with their bodies immersed up to the level of the xiphoid process. 24 Each session was divided into four 10-minute phases: stretching, warming up, strengthening, and relaxation. The first phase included three series of 30 seconds of stretching exercises of the anterior, posterior, and lateral trunk muscles. The second phase included a warm-up exercise consisting of walking at a comfortable speed based on self-assessment. The third phase consisted of upper and lower limb strengthening exercises. In the fourth phase, relaxation movements were performed. 24 Statistical analysis The analysis comprised the average of the three BP and AS measurements indicated by the device. Qualitative variables were presented as numbers and percentages, and quantitative variables as mean ± standard deviation. All continuous variables were subjected to the Shapiro-Wilk normality test. The comparison of means between two samples was performed by Student's t test; for differences in measurements before and after the intervention, the paired version was used, and for differences between groups, the version for independent samples was used. The analyses were performed using the software R, version 3.2.2 (R Foundation for Statistical Computing, Vienna, Austria). In the sample size calculated a priori , the significance level was set at 5% and the power at 90%, using a standard deviation of the differences in BP equal to 5.19 based on a similar previous study. 25 The detection of a difference of 5 required a total of 12 pregnant women with hypertension and 24 pregnant women in the control group, yielding a 2 to 1 ratio, the exact ratio used in our study. Results The sample of this study consisted of 36 pregnant women, of whom 24 (66.7%) were in the CG and 12 (33.3%) were in the HG group. The mean age was 30.4 ± 4.8 years, and the mean body mass index (BMI) was 31.7 ± 7.3 kg/m 2 . At the time of the intervention, the participants’ gestational age was 29.2 ± 3.3 weeks. Among the women participating in the study, 63.9% were black, 80.6% used some type of medication, and 22.2% practiced regular physical activities. There was no difference between the HG and CG in relation to race, physical activity, age, or gestational age. The HG had a higher mean BMI (p < 0.001) (Table 1). 648