Valor do strain atrial esquerdo na predição de eventos em pacientes com estenose mitral reumática

Abstract

Background: Impaired left atrial (LA) function in rheumatic mitral stenosis (MS) may represent primary atrial pathology with an imposed pressure overload. Two-dimensional speckle tracking echocardiography (2D-STE) enables detection of early LA dysfunction, which may improve risk stratification of patients with MS. This study aimed to explore the role of LA function in predicting clinical outcome in MS. Methods: This prospective study including patients with MS from a tertiary center from February 2011 to June 2021. LA function was assessed by 2D-STE during the reservoir phase (LASr). The primary outcome was the development of AF, and the secondary outcome was combined of death or need for valve replacement. Results: Five hundred and three patients with MS, valve area 1.1 ± 0.4 cm2, age 46.4 ± 12.5 years, 421 (84%) females were included. At baseline, 166 patients (33%) were in AF. LASr values in sinus rhythm, new-onset AF, and persistent AF were 15.7%, 11.4%, and 7.2%, respectively. During the 41-month follow-up (interquartile range 10 to 67 months), 62 patients (19%) who were in sinus rhythm developed AF. Multivariate analysis using decision tree (machine learning) showed that LASr ≤ 18.5% was able to predict the development of AF alone. In patients with LASr ≤ 18.5%, new-onset AF occurred in 24.3% and in patients with LASr > 18.5%, only 4.5% had AF (relative risk = 5.4). Using the same methodology but considering the time until the new-onset AF, LASr ≤ 17.9% with LAV > 70.6 ml/m2 present a higher risk of AF, while LASr > 17.9% present a lower risk, without influence of the LAV. Regarding the combined outcome of death and mitral valve replacement including the entire population, 153 patients (34%) had an adverse outcome. In the multivariate model using decision tree considering the time until event, age was the discriminatory variable with a cutoff of 49 years. For patients aged ≤ 49 years, LASr was discriminatory in terms of event free survival time, with a cutoff point of 12.8%. For patients with age ≤ 49 years and LASr ≤ 12.8% whether percutaneous mitral valvuloplasty (PMV) was performed, significantly altered the adverse event-free survival time. However, for patients aged > 49 years, the TR severity and Net atrioventricular compliance became discriminatory variables for event free survival time. Conclusions: In a cohort of patients with MS including a wide spectrum of severity, LASr improves prediction of new-onset AF beyond conventional echocardiographic variables. LASr provides greater accuracy for stratifying patients at risk for adverse outcomes.