IJCS | Volume 33, Nº2, March / April 2020

146 occurrence of cardiovascular events. For hypertensive patients, this biomarker is mainly indicated at initial stages of blood pressure (BP) elevation and in those at low or moderate cardiovascular risk. 8-10 Several non-invasive devices have been developed aiming at estimating central blood pressure and other parameters of arterial stiffness from measurements of peripheral arteries (radial, brachial and carotid arteries), using mathematical algorithms and methods of calibration or estimation. These devices have allowed the determination of several parameters that until then were obtained only by invasive methods. 11 Among the non-invasive methods, arterial tonometry for measurement of PWV is considered the gold-standard method and is validated for intra- arterial pressure measurements. However, electronic tonometers are expensive and technically more difficult to be use. In contrast, oscillometric methods are validated, and faster and easier to perform, providing a better cost-benefit relationship. 12-15 Our objective was to statistically compare results obtained by two non-invasive methods – tonometry and oscillometry – in patients with stage 1 hypertension and patients with borderline hypertension in Brazil. Methods Thiswas adescriptive, cross-sectional study, conducted in patients attending the Liga de Hipertensão Arterial da Universidade Federal de Goiás (LHA/UFG), a program aiming at providing a comprehensive, multidisciplinary care to patients with cardiovascular diseases. The study was approved by the ethics committee of the General Hospital of the Federal University of Goias (approval number 000985/2016) This is one of the sub-studies of the original project entitled “ Correlação entre Valores Obtidos na Medida Central da Pressão Arterial com a Espessura das Camadas Íntima e Média das Artérias Carótidas em Pacientes com Pressão Arterial Sistêmica Limítrofe ou Hipertensos Estágio 1 ” (Correlation of Central Blood Pressure with intima–media thickness of common carotid artery in patients with borderline hypertension or stage 1 hypertension”. Between March 2016 and July 2016, a total of 1,500 medical records of adult patients attending the LHA/UFG were reviewed, and 240 were selected. The selection was based on the data registered during this period, including BP values measured at the last visit. BP was considered as borderline or stage 1 hypertension according to the Brazilian guidelines of arterial hypertension. 1 Patients participating in other research protocols for less than one year and patients with comorbidities – diabetes mellitus, end-stage chronic diseases (chronic renal failure and congestive heart failure), cardiovascular diseases (including coronary artery disease and stroke) were excluded. We intended to select patients at low cardiovascular risk (Figure 1). At a second stage, telephone contact attempts to the patients were made, using the telephone numbers registered on the medical records. When patients could not be contacted, newattempts weremade by theMedical Registry. Three telephone calls were made in different days and times. When telephone contact was successful, patients were invited to participate in the study, and a visit was scheduled at the LHS for those who accepted to participate. Two-hundred fortymedical records were first selected. After screening for the criteria described above and after the telephone contacts were made, the final sample consisted of 31 patients who agreed to participate in the study. Two of these were excluded for the presence of previous cardiovascular event (ischemic stroke) after the review of the medical records, and two were excluded for technical difficulties in obtaining central BP measurements (one using the SphygmoCor® and the other using theMobil O’Graph®), because of the presence of cardiac arrhythmia. Thus, the convenience sample was composed of 27 patients. All patients signed the informed consent form, and then completed a formon anthropometry, life habits, and history of past diseases. Measurements of peripheral and central BP were then taken, registered on the study form and then filed in an electronic database. Peripheral BP (PBP) was measured at the office following the Brazilian Guidelines of Hypertension recommendations. 1 Measurements were taken using semiautomated devices (OMRON®, modelHEM- 705CP, validated by international institutions and recommended for epidemiological applications. 16 Central blood pressure was measured by trained observers, using different methods. The first method consisted of applanation tonometry (portable pressure transducer or sensor), attached to a dedicated software for collection and analysis of the data. The results obtained, as well as the last PBP (measured at the physician’s office) were inserted into the database. For PBP readings, the transducer was placed on the radial artery of patients in Barroso et al. Assessment methods for central blood pressure Int J Cardiovasc Sci. 2020; 33(2):145-150 Original Article