A Systematic Three‐Dimensional Echocardiographic Approach to Assist Surgical Planning in Double Outlet Right Ventricle

Abstract

Double outlet right ventricle (RV) describes a range of pathology where both great arteries arise, either entirely or in greater part from the morphologic RV. Accurate prediction of the optimal surgical approach is challenging. Ideally, assuming that the ventricles are balanced with respect to their size, a biventricular repair is normally attempted. The feasibility of the different surgical options for repair depends on morphologic features including the location and size of the ventricular septal defect, and the relationship of the great arteries. Anderson et al. recommend the term interventricular communication, in preference to ventricular septal defect, when describing the defect between the 2 ventricles in double outlet RV. The outlet muscular septum that forms the upper boundary of the true ventricular septal defect in double outlet RV is often sited in a position above the right ventricular cavity. Any closure of the true ventricular septal defect beginning at the crest of the septum would involve crossing into the right ventricular space. The remaining defect between the 2 ventricles is therefore best described as the interventricular communication. The term interventricular communication has been used in the text for the purpose of consistency. The position of this interventricular communication in relation to the great vessels is variable. These are described as being subaortic, subpulmonary, or noncommitted, where the interventricular communication lies remote to either great vessel’s origin. In rare cases, there is fibrous continuity between the 2 arterial valves and the interventricular communication that lies beneath these is described as being doubly committed. Two-dimensional echocardiography has traditionally been used to plan surgical intervention, utilizing multiple separate sonographic views and “sweeps.” Three-dimensional (3D) echocardiography has the advantage of incorporating a depth of field to the sonographic images so that the atrioventricular valves, ventricular septal defect, and great arteries can be visualized within a single sonographic projection, obtained by cropping of a 3D echocardiographic volume. This has the potential to enhance understanding of the relationship of the anatomic structures needed for surgical planning. We describe a systematic 3D echocardiographic approach, which we have adopted to assist decision making for the surgical management of this group of lesions. This approach addresses the anatomic concerns with respect to biventricular repair and whether a RV to pulmonary artery conduit will be required. Biventricular repair options include closure of the interventricular communication with or without an arterial switch procedure. Complex interventricular baffles can necessitate enlargement of the interventricular communication and there may be a need to relieve subpulmonary or subaortic stenosis. Straddling atrioventricular valves may preclude septation and single ventricle palliation is sometimes pursued. The echocardiographic approach is described below using clinical examples. Address for correspondence and reprint requests: John M. Simpson, M.D., F.R.C.P., F.E.S.C., 6th Floor Sky Offices, Evelina Childrens Hospital, Westminster Bridge Road, London SE1 7EH, UK. Fax: +44-207-188-4556; E-mail: john.simpson@gstt.nhs.uk