ABC | Volume 112, Nº2, February 2019

Original Article Dippe Jr. et al Study of myocardial perfusion in obese individuals without known IHD Arq Bras Cardiol. 2019; 112(2):121-128 Methods Patients Obese patients without known IHD who had undergone SPECT-MPI were studied between January 2011 and December 2016. The following clinical data were prospective collected using a standardized questionnaire – age, sex, weight, height, BMI, symptoms before the SPECT-MPI test (typical, atypical or no pain, and tiredness), previous heart disease or procedures (coronary cineangiography, acute myocardial infarction, myocardial revascularization surgery and coronary angioplasty), SAH, DM, dyslipidemia, smoking, use of medications and family history of IHD). Regarding SPECT-MPI, we assessed the type of stress used during the test, treadmill test (TT) alone or combined with pharmacological stress test. Physical exertion during the tests was quantified by metabolic equivalents (METs). We also analyzed myocardial perfusion patterns (normal, ischemia alone or associated with fibrosis), and post-stress left ventricular ejection fraction (LVEF). All tests were performed using a CardioMD (Philips, Milpitas, CA, USA) or a Vertex (ADAC, Milpitas, CA - USA) gamma camera. All images were reviewed immediately after acquisition, and an additional prone imaging was always obtained when the presence of artifacts was suspected. Both images were considered to define the type of myocardial perfusion defect and the final report also. Statistical analysis All continuous variables are shown as mean and standard deviation, and all categorical variables as absolute values and percentages. Normal distribution of continuous variables was tested by Shapiro-Wilk and Shapiro-Francia tests. Unpaired Student’s t test was used to compare the means of continuous variables with normal distribution, and the chi-square test used for analysis of binominal variables. A p-value<0.05 was considered statistically significant. The association of clinical variables, type of the test stress, and left ventricular function with abnormal SPECT-MPI was analyzed by univariate logistic regression, followed by multivariate analysis. The respective odds ratio (OR) and 95% confidence intervals were also calculated. All analyses were performed using a specific software, the Stata Statistical Software, Release 11 (College Station, TX: StataCorp LP). Results Demographic characteristics of the patients From January 2011 to December 2016, a total of 5,526 obese patients were referred for SPECT-MPI. Table 1 shows demographic characteristics of the patients. Demographic characteristics of the patients by sex The total sample was composed of 2,921 women and 2,605 men. Table 2 shows demographic characteristics of the patients by sex. Distribution of patients by BMI Most patients (70.2%) were class I obese. Table 3 shows the distribution of the patients by BMI. Percentage of abnormal perfusion according to the BMI Among obese individuals (n = 5,526), there was no statistically significant difference in the number of patients Table 1 – Demographic characteristics of the patients without known ischemic heart disease and body mass index (BMI) ≥ 30kg/m 2 (n = 5,526) Characteristics Mean (standard deviation) or number (percentage) Age 59.4 (12.2) BMI (kg/m 2 ) 33.9 (3.7) Male sex 2.605 (47.1%) Diabetes mellitus 1,727 (31.5%) Systemic arterial hypertension 4,106 (74.3%) Family history of IHD 1,081 (19.5%) Smoking 466 (8.4%) Dyslipidemia 2,996 (54.2%) Symptoms before SPECT-MPI Asymptomatic 2,996 (55.0%) Atypical angina 1,210 (22.3%) Typical angina 362 (6.6%) Tiredness 878 (16.1%) Stress protocol Physical 3,576 (64.7%) Pharmacological 1,950 (35.3%) Physical exertion, in METs 8.52 (2.37) LVEF 59.2 (17.6) LVEF > 50% 4,821 (92.9%) LVEF 30 - 49% 330 (6.4%) LVEF < 30% 38 (0.7%) Abnormal SPECT-MPI 1,288 (23.3%) Ischemia alone 1,228 (22.2%) Ischemia > 10% of the LV 74 (1.3%) Fibrosis alone 22 (0.4%) Fibrosis and ischemia 38 (0.7%) BMI: body mass index; IHD: ischemic heart disease; METs: metabolic equivalents; LVEF: post-stress left ventricular ejection fraction; SPECT‑MPI: myocardial perfusion imaging with single-photon emission computed tomography; LV: left ventricle. 122