IJCS | Volume 32, Nº2, May/June 2019

254 Rosário et al. Adductor pollicis muscle in heart failure Int J Cardiovasc Sci. 2019;32(3)253-260 Original Article of body composition; however, difficult logistics associated with its implementation hinders the routine use of this technique in clinical practice. In contrast, electrical bioimpedance (EBI) is considered an alternative and appropriate instrument capable of estimating the body components, distribution of fluids, and cellular quality and integrity. 7 Anthropometric variables obtained in the upper part of the body, such as the arm muscle circumference (AMC), can also be considered good indicators of somatic protein mass since they are less affected by the presence of edema. 5 In this sense, the measurement of the thickness of the adductor pollicis muscle (APM) emerges as a promising alternative to evaluate themuscle compartment, since it is a simple, noninvasive, and low- cost method. 8,9 The APM is the onlymuscle in the human bodywhose thickness can be directly measured without requiring estimating equations, reflecting the loss of working capacity due to limitations from the underlying disease. 8,9 Due to the lack of scientific evidence on the applicability of APM thickness and its reliability in classifying the nutritional status in individuals with HF, the objective of this study was to evaluate the APM thickness in patients with HF and correlate the results with conventional anthropometric parameters for assessment of the somatic nutritional protein status and with EBI parameters. Methods This cross-sectional study evaluated patients regularly attending the Heart Failure Outpatient Clinic at Hospital Universitário Pedro Ernesto (HUPE) and was approved by the institution’s Research Ethics Committee (HUPE/ UERJ, n. 47828915300005259). All patients were previously informed about the methods and objectives of the study and signed an informed consent form. Considering the absence of data on the average values of APM thickness in patients with HF, standard deviation values for APM thickness found in patients undergoing cardiac surgery 9 were considered to determine the sample size required for this study. Thus, a minimum of 66 patients would be sufficient to ensure a maximum estimation error of 0.7 mm for APM thickness, with a significance level of 5%. A total of 90 patients with a diagnosis of HF, of both genders, and aged between 18 and 74 years were considered eligible. The exclusion criteria were patients with clinical evidence of edema and ascites, amputees, with a pacemaker, or with a BMI < 16 kg/m² or > 34 kg/m², since most equations used to estimate body composition using EBI are unable to predict reliably the body composition in extreme BMI values. 10 Patients were also excluded when failing to follow the standardization protocol for EBI or not using diuretics, resulting in a sample of 74 patients. The etiology and the HF functional class were defined according to the proposal by the New York Heart Association (NYHA). 11 Values of EF were obtained by echocardiography at the moment of the clinical and nutritional evaluation of the patient. The presence of comorbidities was obtained from the patients’ clinical records. A patient was considered as having type 2 diabetes mellitus when presenting fasting glucose ≥ 126 mg/dL on at least two occasions or using hypoglycemic agents, 12 and as having chronic renal disease when presenting a glomerular filtration rate < 60 mL/min for 3 months. 13 The assessment of the nutritional statuswas performed by two previously trained nutritionists and consisted in the assessment of anthropometric measures and EBI. Anthropometry Body mass was measured with a mechanical scale (Balmack ® , São Paulo, Brazil) with a maximum capacity of 200 kg and subdivisions of 100 grams. Height measurement was obtained with a stadiometer coupled to the scale mentioned above, with an accuracy of 0.1 cm, following the technique proposed by Lohman et al. 14 The nutritional status was assessed according to the BMI, which was classified according to the proposal by the World Health Organization. 15 The technique described by Harrison et al. 16 was used to measure the arm circumference (AC) and triceps skinfold (TSF). The AC was measured on the dominant armusing an inelastic measuring tape. The TSF thickness was measured in triplicate with the adipometer Lange Skinfold Caliper (Cambridge Scientific Industries, Inc., Watertown, MA, USA), with an accuracy of 1mm, and the mean value of the three measurements was used in the analysis. The AC and TSF values were used to calculate the AMC and arm muscle area (AMA), according to the formulae described by Frisancho. 17 The AMC was classified according to the calculation of the percentage of adequacy in relation to the value corresponding to the 50 th percentile according to gender and age, and later compared with the percentages of reference established