Predominant Posterior Annular Dilatation Is Associated with Vena Contracta Morphology in Atrial Functional Tricuspid Regurgitation

Abstract

The exact relationship between tricuspid valve geometry and vena contracta (VC) morphology has pathophysiologic and mechanistic implications in patients with atrial functional tricuspid regurgitation (AF-TR). The aim of this study was to investigate tricuspid valve geometric and VC morphologic characteristics and compare them between AF-TR and ventricular functional tricuspid regurgitation (VF-TR) in sinus rhythm. Transesophageal three-dimensional echocardiography data sets of the tricuspid valve were acquired in 439 patients with moderate to severe tricuspid regurgitation. Forty-eight patients with AF-TR and 48 with VF-TR in sinus rhythm matched for age, sex, body surface area, and VC area according to three-dimensional echocardiography-based pathogenic stratification were selected. VC morphology was determined by the ratio of anteroposterior to anterolateral-posteromedial diameter using color Doppler three-dimensional echocardiography. Patients with AF-TR had higher posterior annular perimeter/total annular perimeter ratios than patients with VF-TR in sinus rhythm (P<.001). Despite similar VC areas, patients with AF-TR had larger VC anteroposterior diameters and smaller VC anterolateral-posteromedial diameters, with resultant higher VC anteroposterior/anterolateral-posteromedial diameter ratios (P<.001). On multivariable analyses, posterior annular perimeter (coefficient=0.013; 95% CI, 0.001 to 0.024) and posterior leaflet length/annular perimeter ratio (coefficient=-2.372; 95% CI, -3.591 to -1.154) were multivariable determinants of VC morphology in AF-TR. Additionally, posterior annular perimeter/total annular perimeter was strongly related to right atrial volume in AF-TR but not in VF-TR. Possible contributions to the initial mechanism of AF-TR include right atrial remodeling, predominant posterior annular dilatation, and insufficient adaptive posterior leaflet growth, which may have therapeutic implications in this setting.