ABC | Volume 110, Nº4, April 2018

Original Article Applicability of Longitudinal Strain of Left Ventricle in Unstable Angina Natasha Soares Simões dos Santos, Andrea de Andrade Vilela, Rodrigo Bellio de Mattos Barretto, Marcela Paganelli do Vale, Mariana Oliveira Rezende, Murilo Castro Ferreira, Alexandre José Aguiar Andrade, Nelson Henrique Goes Scorsioni, Olívia Ximenes de Queiroga, David Le Bihan Instituto Dante Pazzanese de Cardiologia, São Paulo, SP – Brazil Mailing Address: Natasha Soares Simões dos Santos • Av. Dante Pazzanese, 500. Postal Code 04012-909, Vila Mariana, São Paulo, SP – Brazil E-mail: natashasimoes@hotmail.com , mariananatasha@yahoo.com.br Manuscript received January 31, 2017, revised manuscript November 13, 2017, accepted November 22, 2017 DOI: 10.5935/abc.20180062 Abstract Background: Unstable angina (UA) is a common cause of hospital admission; risk stratification helps determine strategies for treatment. Objective: To determine the applicability of two-dimensional longitudinal strain (SL2D) for the identification of myocardial ischemia in patients with UA. Methods: Cross-sectional, descriptive, observational study lasting 60 days. The sample consisted of 78 patients, of which fifteen (19.2%) were eligible for longitudinal strain analysis. The value of p < 0.05 was considered significant. Results: The group of ineligible patients presented: a lower proportion of women, a higher prevalence of diabetes mellitus (DM), use of ASA, statins and beta-blockers and larger cavity diameters. The main causes of non-applicability were: presence of previous infarction (56.4%), previous CTA (22.1%), previous MRI (11.5%) or both (16.7%) and the presence of specific electrocardiographic abnormalities (12.8%). SL2D assessment revealed a lower global strain value in those with stenosis greater than 70% in some epicardial coronary arteries (17.1 [3.1] versus 20.2 [6.7], with p = 0.014). Segmental strain assessment showed an association between severe CX and RD lesions with longitudinal strain reduction of lateral and inferior walls basal segments; (14 [5] versus 21 [10], with p = 0.04) and (12.5 [6] versus 19 [8], respectively). Conclusion: There was very low SL2D applicability to assess ischemia in the studied population. However, the global strain showed a correlation with the presence of significant coronary lesion, which could be included in the UA diagnostic arsenal in the future. (Arq Bras Cardiol. 2018; 110(4):354-361) Keywords: Angina, unstable / physiopathology; Ventricular Dysfunction, Left; Myocardial Ischemia / physiopathology; Strain; Echocardiography / methods. Introduction In United States, unstable angina (UA) is the most common cardiovascular cause of hospitalization and is responsible for most hospitalizations in coronary units. 1 The diagnosis of UA is performed by clinical criteria based on angina duration and intensity. 2 UA patient has a variable prognosis for unfavorable events such as acute myocardial infarction (AMI), recurrence of angina, necrosis biomarkers, ventricular function and need for myocardial revascularization. 3 Speckle tracking (ST) is a technology introduced in the 1980s that allows the quantification of global and regional myocardial deformity by tracking the natural heart muscle "acousticmarks" by ultrasound, presenting reduced values in presence of myocardial ischemia. 4,5 ST allowsmyocardial strain calculation and has shown great utility in the identification of subendocardial ischemia as in unstable angina, with greater sensitivity and specificity than two-dimensional echocardiogram. 6 However, for ST to track adequately speckles, there are some variables that may interfere in deformity analysis, so when present, they may give erroneous results or even impede myocardial strain analysis. In addition, for myocardial ischemia identification in UA patients, infarction previous myocardial presence or other myocardial injury (such as significant valvar heart disease) may alter myocardial deformity and cause an incorrect analysis of deformity decrease true cause. These are the variables that interfere in myocardial deformity correct analysis, and for that reason, they are considered exclusion criteria in the majority of published studies (aimed at analyzing acute ischemia): previous infarction, atrial fibrillation, left bundle branch block, ventricular arrhythmia aortic and/or mitral valvar disease, previous cardiac surgery, ventricular hypertrophy, cardiac pacemaker and inadequate acoustic window. 7 The main objective is to study the applicability prevalence of two-dimensional longitudinal strain (SL2D) in all hospitalized patients diagnosed with UA during the 60-day observation period. The secondary objective is to evaluate the diagnostic capacity of SL2D in the identification of culprit vessel due to ischemic event in UA patients. 354