Influence of percutaneous occlusion of atrial septal defect on left atrial function evaluated using 2D speckle tracking echocardiography

概要

Atrial septal defect (ASD) with a left-to-right shunt is the most prevalent congenital heart disease. Patients with ASD develop right heart failure, atrial arrhythmias, and eventually pulmonary hypertension if a significant right heart volume load persists. Surgical outcomes have been very good for patients with ASD. Less invasive percutaneous occlusion using a specific device has recently been introduced as an alternative to surgery. The outcomes of percutaneous occlusion and surgery are comparable, and percutaneous occlusion has become more popular for ASD closure.

Although ventricular functions or volumes after percutaneous occlusion of ASD have been studied, information about the effects of percutaneous occlusion on atrial performance is limited. Several methods have been developed to measure atrial function, including left atrial (LA) strain, indicating LA reservoir, conduit, and booster pump function. Representative methods of evaluating strain on echocardiographic Doppler images (TDI) of tissues have the disadvantages of angle dependence and poor reproducibility and the potential for compromised evaluative accuracy. A method that is independent of angle is needed to accurately measure strain. Two-dimensional echocardiographic speckle tracking (2DE-ST) is a novel, noninvasive way to resolve the issue of angle dependence. It systemically evaluates local or global myocardial movement, speed, and function by automatically tracking specific myocardial speckles. Atrial function has recently been analyzed using this method, but it has not been applied to assessing LA function among patients with ASD.

The present study aimed to determine LA function in 43 children with ASD and 13 controls based on LA strain measured by two-dimensional echocardiographic speckle tracking (2DE-ST). Among these children, 12 underwent surgery (ASD-S), 31 had device closure (ASD-D), and 13 were included as controls. The ASD-D group was subclassified according to the size of the ASD device (mm) inserted per body surface area (BSA; m2) as small (n = 10), medium (n = 10), or large (n = 11).

LA strain was significantly decreased after ASD-D but was not significantly altered after ASD-S, indicating that percutaneous occlusion of an ASD might decrease LA function. The atrium reservoir function during the LV systolic phase was compromised by the device causing an extended disturbance, which led to a decrease in LA compliance. Since LV contraction and dilation were preserved, decreased LA reservoir function was affected by LA compliance rather than LV function. The atrium conduit function during the early diastolic LV filling phase is compromised due to resistance to the device. The impaired function of the atrial booster pump that becomes compromised by disturbed contraction caused by the device, which results in decreased LA contractility. Furthermore, the size of the ASD device negatively correlated with LA strain. In fact, the size of the ASD device negatively correlated with the LA reservoir and conduit function. These data suggest that careful follow-up of LA function might be needed for patients with larger devices.

In conclusion, analyzing LA strain using 2DE speckle tracking allowed simple and valuable assessment of the LA reservoir, conduit, and booster pump function of ASD after treatment. We showed that LA function was decreased after ASD occlusion in the ASD-D group compared with the ASD-S group. Furthermore, LA reservoir and conduit function negatively correlated with device size. These findings warrant further investigation of the relationship between long-term atrial function and complications after ASD treatment, which would facilitate more appropriate decisions regarding treatment strategies.