ABC | Volume 111, Nº1, July 2018

Original Article Luo et al Right ventricular function by 2D-STE in SLE Arq Bras Cardiol. 2018; 111(1):75-81 volunteers as control group (Group A) (M:F = 3:27, aged 23-51 years, mean age: 42.1 ± 10.5 years, mean pulmonary artery systolic pressure – PASP 22.54 ± 4.31 mmHg) were eligible to participate in this study. The study was conducted between October 2015 and May 2016 in our hospital. The eligibility criteria of SLE diagnosis met the 2012 Systemic Lupus International Collaborating Clinics (SLICC) standard criteria. 12 Exclusion criteria included left ventricular heart failure, congenital heart diseases, coronary heart disease, cardiomyopathy and valvular heart disease, pericardial effusion, use of cardiotoxic drugs, history of hypertension, infectious myocarditis and pulmonary obstructive diseases. Eight patients with poor-quality echocardiographic imaging and ten patients unwilling to participate in the study were excluded. The selected patients were divided into three groups according to the PASP estimated by echocardiography: Group B included 37 patients with PASP ≤ 30 mmHg, which was considered as a non-PH group (M:F = 4:33, aged 21-51 years, mean age 45.3 ± 8.4 years, mean PASP 23.61 ± 3.11 mmHg); Group C included 34 patients with 30 < PASP < 50 mmHg, considered as mild PH group, (M:F = 4:30, aged 20-52 years, mean age: 41.3 ± 9.6 years, mean PASP 45.11 ± 5.50 mmHg); and Group D included 31 patients with PASP ≥ 50 mmHg, which was considered as moderate to severe PH group (M:F = 3:28, aged 23-51 years, mean age: 43.3 ± 7.5 years, mean PASP: 72.95 ± 7.92 mmHg). All subjects gave their written informed consent after receiving a detailed explanation of the study protocol. The design proposal, methods of data collection, and analysis of this study were approved by the ethics committee of the hospital. Image acquisition and analysis Two-dimensional echocardiographic examinations were carried out with a GE Vingmed Vivid 7 (GE Vingmed Ultrasound, Horten, Norway) scanner equipped with a 1.7-3.4 MHz transducer (M3S probe). After a 15-minute rest in the supine position in a quiet room at 23°C, blood pressure (BP) and heart rate (HR) of all patients were measured three times and the mean values were calculated. An electrocardiogram (ECG) was also recorded simultaneously. The measurements and calculated formulas of the parameters in our study followed the 2015 American Society of Echocardiography and the European Association of Cardiovascular Imaging (ASE-EACVI) recommendations for chamber quantification. 13 During ECG recording at a stable frame rate in the left lateral position, the RV end-diastolic diameter (RVED) was obtained in the middle third of RV inflow, approximately halfway between the maximal basal diameter and the apex, at the level of papillary muscles at end-diastole in the RV-focused apical four-chamber view with left ventricle (LV) apex at the center of the scanning sector; the RV anterior wall thickness (RVAW) was obtained below the tricuspid annulus, at a distance approximating the length of the anterior tricuspid leaflet in its fully open position and parallel to the RV free wall as seen from a subcostal four-chamber view. Both parameters were measured by a conventional, two‑dimensional grayscale echocardiography. 13 Tricuspid annulus plane systolic excursion (TAPSE) and peak systolic velocity of tricuspid annulus (S wave) were measured through the lateral portion of the tricuspid annulus by M-mode echocardiography and pulsed-wave tissue Doppler imaging (TDI) in the apical four-chamber view, respectively. RV fractional area change (RV FAC) was measured and calculated in the RV-focused apex four-chamber view: RV FAC (%) = 100 × (end-diastolic area [EDA] - end-systolic area [ESA]) / EDA. 13 Three-dimensional echocardiographic RV ejection fraction (3D RV EF) was also measured: 3D RV EF (%) = 100 × (end‑diastolic volume [EDV] - end-systolic volume [ESV]) / EDV. 13 Left ventricular ejection fraction (LVEF) was measured by Simpson’s biplanemethod. PASP was estimated according to the simplified Bernoulli equation: PASP = 4×V² (V= peak velocity of tricuspid regurgitation) + right atrial pressure (RAP). RAP was estimated through echocardiography based on the diameter and respiratory variation in diameter of the inferior vena cava (IVC). A diameter of IVC < 2.1 cm that collapses > 50% with a sniff suggests there is a normal RA pressure of 3 mmHg; while an IVC diameter > 2.1 cm that collapses < 50% with a sniff or < 20% on quiet inspiration suggests a high RAP of 15 mmHg; if the IVC diameter and collapse do not fit this paradigm, an intermediate value of 8 mmHg would be used. 14 All images were digitally recorded in hard disks on offline analysis (EchoPAC version 8, GE Vingmed Ultrasound). Two-dimensional dynamic images were recorded for the subsequent analyses. A frame rate of 40-80 frames/s acquisition was used. All 2D-STE data were measured by averaging data of three heartbeats. We selected the most stable cardiac cycle for generation of the strain curve. After manually tracing the RV endocardium on apical four‑chamber view, a region of interest (ROI) divided into six segments was automatically generated. Only RV free wall segmental strain was analyzed. Using a single frame from end-systole, the RV free wall segments were manually mapped by marking the endocardial border and the width of the myocardium. The parameters of ε and SRs, SRe and SRa were measured in RV free wall for basal, middle and apical segments, respectively, from the apical four-chamber view. Statistical analysis The data were analyzed with SPSS 17.0 for Windows (SPSS, Chicago, IL, USA). Unpaired Student’s T-test was performed for continuous variables, which were all normally distributed. Numeric variables are presented as the mean ± standard deviation (SD). One-way analysis of variance (ANOVA) was performed to test for statistically significant differences among the four groups. Continuous data were compared between individual groups using the Student-Newman-Keuls post-test to test for statistically significant differences. All statistical tests were two-sided, and p < 0.05 was set for statistical significance. Results Patient characteristics Between the four groups, there were no significant differences in age, sex, bodymass index (BMI), body surface area (BSA), systolic blood pressure (SBP), and diastolic blood pressure (DBP). Nevertheless, the HR in group Dwas significantly higher than that in the other three groups (Seen in Table 1). 76