1350112 - Chronic AR in asymptomatic children and young adults: Limited accuracy of end-systolic dimension

The timing for intervention in individuals with chronic aortic regurgitation (AR) is typically based on symptoms and/or reduced function. In asymptomatic patients with normal function, increased left ventricular end-systolic dimension (LVESD) ( >50 mm or >25 mm/m2), measured by echocardiography, is a class IIa indication for intervention. Cardiac magnetic resonance (CMR) is the gold standard for the evaluation of ventricular size and function but is not incorporated into the current guidelines for aortic regurgitation. The aim of this study was to examine associations between LVESD and volumes using CMR.

Methods:

Asymptomatic children and young adults with chronic aortic regurgitation who had undergone CMR at a single institution between 2017 - 2022 were retrospectively reviewed for LV volumes and dimensions. Cases were excluded if there was an associated complex diagnosis (TGA, DORV, single ventricle), urgent and clear indication for intervention, and/or those with systolic dysfunction (LVEF < 55%). Studies were performed at 1.5T (Siemens Aera system) using standard bSSFP cine for short and long axis cine imaging. LVESD was measured on the 3-chamber view, in keeping with usual echocardiographic M-mode positioning between the tips of the mitral leaflets and the papillary muscles. Ventricular volumes and ejection fraction were measured in the standard clinical method. LVESD, indexed to the body surface area, was compared to the LVESVi (ml/m2) and LVESV Z-score.

Results:

Thirty-one subjects (mean 15.6 years, 71% male) were included. CMR measures, including LVESD, are summarized in Table 1. 2D LVESD had a poor correlation with LVESVi (R2=0.12, p=0.06), but moderate with LVESV Z-score (R2=0.39, p< 0.01) (Figures 1 & 2). However, of the 9 subjects with LVESD > 25 mm/m2, 5 had LVESV Z-score < 3 and 2 were normal Z-scores. In 5 subjects, an LVESD < 25 mm/m2 was associated with a LVESV >3.

Conclusion:

In an asymptomatic pediatric and young adult population with aortic regurgitation and normal ejection fractions, guideline-based suggestions for interventions using standard 2D LV dimensions do not compare well to LV volumes obtained with CMR. These findings highlight the need to develop CMR volume-based interventional guidelines for aortic regurgitation.