ABC | Volume 110, Nº4, April 2018

Original Article Santos et al Applicability of LV S2DL in unstable UA Arq Bras Cardiol. 2018; 110(4):354-361 Figure 1 – Polar map with coronary irrigation correlation. AD: anterior descending coronary artery; CX: circumflex coronary artery; RD: right coronary artery. A n t e r o s e p t a l A n t e r i o r L a t e r a l I n f e r i o r I n f e r o l a t e r a l I n fe r o s e p t a l 2 1 7 8 6 12 16 11 5 3 9 4 10 15 17 14 13 AD CX RD Results of cardiac catheterization (CC) and Coronary Angiography by Computed Tomography (CACT) exams were also analyzed. Stenosis greater than or equal to 70% in epicardial coronary arteries or stenosis greater than or equal to 50% in left main coronary artery (LMCA) was considered. The sample was divided into two groups: Group A - patients in whom it was possible to analyze by SL2D and Group B - patients in whom analysis by SL2D was not possible. The research protocol was submitted and approved by the institution's Ethics and Research Committee. There was no interference in individual medical conduct due to participation in the study. Such conduct was based on ER and CU routine that corresponds to US and national guidelines 3,14 for UA patients treatment patients. Statistical analysis Statistical analysis was performed with Statistical Package for Social Sciences (SPSS), version 19.0. Kolmogorov-Smirnov and Shapiro-Wilk tests were performed to verify our sample normal distribution. As the normality hypothesis was rejected, we used nonparametric tests for analysis. Groups were compared using Mann-Whitney test and Fisher exact test as appropriate. Continuous variables were presented as median and interquartile range, and categorical variables were expressed as percentage (%). ROC curve was used to evaluate SL2D discriminative power in severe coronary stenosis identification (≥ 70%) in UA patients. Level of significance was 5%. Results We evaluated 93 patients diagnosed with UA at admission to ER; however, fifteen (16.2%) patients were excluded from the study due to diagnosis change during hospitalization, 13 (14%) cases with non-ST-segment AMI, one (1.1%) with UA post-MI and one (1.1%) with type A aortic dissection. At the end, 78 UA patients were investigated, of which fifteen (19.2%) were eligible for longitudinal strain analysis. Main population clinical characteristics are summarized in Table 1. About 70% of sample had no change in QRS complex duration or morphology complex; more than half (60.3%) showed no change in ventricular repolarization. Five patients (6.4%) presented ST segment depression on admission. Main electrocardiographic changes are detailed in Table 2. Of the 63 patients in whom the longitudinal strain was not applied, 40 (63.5%) performed two-dimensional echocardiography during ER stay. Main echocardiographic findings of this population, including the 15 patients submitted to SL2D, are shown in Table 3. In total, 50 patients completed the investigation with CC and five with CACT. In the first exam, three patients presented LMCA severe lesions (3.9%), 22 (28.2%) anterior descending coronary artery lesions (AD), 21 (26.9%) in right coronary artery, 2%) in circumflex coronary artery (CX). In patients submitted to CACT, one presented AD severe damage (1.3%) and one in RD (1.3%). During hospitalization, 23 patients (29.5%) were submitted to intervention. Coronary transluminal angioplasty (CTA) was the main revascularization therapy. In three cases (3.8%), revascularization was surgical. Comparing patients eligible for longitudinal strain analysis (group A) to those not eligible (group B), we found that group B had a lower proportion of women, a higher prevalence of diabetes, left cavities larger dimensions, larger root aorta diameter and lower systolic function on two-dimensional echocardiography; in addition to a higher ASA use rate, statins and beta-blockers, according to the data in Table 4. Main causes to strain non-applicability were presence of prior infarction (56.4%), previous CTA (22.1%), prior surgical (CTA) revascularization (MRI), MRI and previous CTA (16, 7%), and presence of the following electrocardiographic alterations: LBBB, AF, pathological Q wave and pacemaker pace (12.8%). In group A, patient majority presented low or intermediate risk, as detailed in Table 5. 356