Structural and functional abnormalities of cardiac chambers in Barlow disease without significant mitral regurgitation

Abstract

Abstract Background Limited and conflicting data have been reported on the existence of an early chamber remodelling in patients with Barlow disease (BD) without significant mitral regurgitation (MR). Purpose To explore the presence of left ventricular (LV) and left atrial (LA) morphological and functional abnormalities, evaluated by conventional and speckle-tracking echocardiography, in patients with BD and without significant MR; in addition, potential determinants of MR progression in these patients have been investigated. Methods We retrospectively identified consecutive patients with BD evaluated in two tertiary centers between 2010 and 2021. Only patients with MR graded from trivial to mild-to-moderate, as defined by an integrated multiparametric echocardiographic assessment, were selected. BD patients were matched with healthy controls with similar demographic characteristics and prevalence of cardiovascular risk factors, in a 1:1 ratio. A comprehensive echocardiographic evaluation, including LV and LA strain assessment by speckle-tracking analysis, was performed in all patients. Follow-up echocardiograms, when available, were reviewed in BD patients to evaluate the MR progression. Results A total of 231 patients with BD were included, of which 109 (56%) had trivial or mild MR and the remaining 122 (44%) had mild-to-moderate MR. As showed in Figure 1, patients with BD showed increased LV dimensions and indexed LV mass (LVMi), as compared with controls (all p<0.001); LV remodelling worsened with higher degree of MR (trivial-mild vs mild-to-moderate) and was accompanied by an increased prevalence of eccentric LV hypertrophy (eLVH). Conversely, parameters of LV systolic performance, including LV strain, were similar to controls and between the two groups. In addition, BD patients had larger LA volumes and more impaired LA reservoir strain than controls (p<0.001), without differences in the latter according to MR severity. Multivariable linear regression analyses in the overall population identified BD and MR grade as independent predictors of remodelling markers (LV dimensions, LVMi and LA volumes), and BD as independent correlate of LA reservoir strain. Progression to moderate-to-severe or greater MR was observed in 51 subjects (on 172 with available follow-up) after a median time of 38 (range: 24-68) months. On multivariable Cox regression analysis, LVMi (or alternatively eLVH), together with age, MR grade and the presence of mitral annular disjunction emerged as independent predictors of MR progression (Figure 2). Conclusions Patients with BD and no significant MR show an early LV and LA remodeling, together with a mild impairment of LA reservoir strain, but not of LV function. LV remodelling, and the presence of eLVH in particular, portends a higher risk of MR progression.Comparative echocardiographic analysisMultivariable Cox regression analyses