ABC | Volume 113, Nº6, December 2019

Original Article Elias Neto et al. Great arteries behavior during orthostasis Arq Bras Cardiol. 2019; 113(6):1072-1081 and in individuals with untreated mild-to-moderate arterial hypertension. We tested the hypothesis that orthostatism could lead to increased PWV compared to the supine positions and considering the influence of blood pressure, age and heart rate. Methods Patient characteristics To define the sample size, we used studies that evaluated PWV in supine position. 4-7 The study included 93 individuals, 74 males and 19 females whose ages ranged from 18 to 75 years (42 ± 16 years). Twenty‑nine (31.1%) individuals had systolic blood pressure levels ≥140 and/or diastolic blood pressure levels >90mmHg. These individuals either had undiagnosed arterial hypertension or had voluntarily interrupted the antihypertensive treatment for more than 30 days. Their anthropometric and hemodynamic characteristics are shown in Table 1. The exclusion criteria were as follows: clinical history or evidence of any type of cardiac structural disease; overweight or obesity; diabetes mellitus; smoking; dyslipidemia; peripheral vascular disease; chronic renal failure; clinical data suggestive of dysautonomia; and orthostatic intolerance or previous vasovagal events. Patients with arterial hypertension on antihypertensive treatment and patients on any medication that could interfere with the results of the parameters assessed or that could account for the occurrence of orthostatic hypotension during the tilt test were also excluded from the study. Automatic measurement of carotid-femoral PWV Carotid-femoral PWV index, a measure of aortic stiffness, was assessed with an automatic device (Complior, Colson, France) that measures the time delay between the rapid upstroke of the feet of simultaneously recorded pulse waves in the carotid and femoral arteries by using 2 pressure transducers (TY-306 type; Fukuda Deshi Co., Tokyo, Japan). PWV was calculated as the ratio between the distance and the foot‑to‑foot time delay and was expressed in meters per second. (6). All PWV measurements in the supine position were taken and assessed by a single observer. Obtainment of PWV during the tilt test required 2 researchers, who were acquainted with the technique in the supine position and were trained for PWV measurement in the orthostatic position. Protocol of the tilt test associated with PWV measurement All individuals were assessed in the morning. They were instructed to fast for 12 hours. Prior to the examination, anthropometric measurements of weight, height, and waist and hip perimeters were taken. Then, the individuals were placed in the supine position on a mechanical table of tilt test. After a 20-minute rest, during which the individuals were instructed about the dynamic sequence of the protocol, the following baseline measurements were taken: PWV, heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean blood pressure (MBP) and pulse pressure (PP). After that, the patients were tilted at an angle of 70º. The tilt test lasted 20 minutes. The measurements of parameters monitored during tilt testing were performed at 2-minute intervals and 2 minutes after returning to the supine position. Electrocardiographic monitoring was continuously performed. Blood pressure was noninvasively measured at 2-minute intervals using the Omega 1400 monitor (Invivo Research Laboratories, USA) while PWV measurements were being taken or when the patient reported any symptom or had clinical signs or electrocardiographic abnormalities suggestive of that diagnosis. Statistical analysis Anthropometric, biological and hemodynamic characteristics were expressed as mean ± standard deviation (SD). One‑way analysis of variance (ANOVA) was used to compare hemodynamic parameters obtained at baseline condition, Table 1 – Anthropomorphic and hemodynamic characteristics of the participants Characteristics Participants (n = 93) Sex Male (n = 74) Female (n = 19) Mean ± Standard deviation Age, years 42 ± 16 Weight, kg 71 ± 12 Height, cm 1,7 ± 0,1 BMI, kg/m 2 24,7 ± 3,1 SBP, mmHg 130 ± 18 DBP, mmHg 82 ± 13 MBP, mmHg 99 ± 15 HR, bpm 66 ± 11 PP, mmHg 47 ± 13 BMI: body mass index; SBP: systolic blood pressure; DBP: diastolic blood pressure; MBP: medium blood pressure; PP: pulse pressure; HR: heart rate. The continuous values are expressed as mean ± SD. 1073