Application of an interactive, stereoscopic three-dimensional viewer to evaluate atrial septal defects in five dogs

Definitive closure of atrial septal defects (ASDs) has been reported in dogs utilizing a variety of methods, including device occlusion. We report five dogs with ASD in which multidimensional imaging with computed tomography angiography (CTA) and three-dimensional reconstruction was utilized to assess suitability for device occlusion. Three dogs were initially evaluated for an asymptomatic murmur noted during routine preventative care visits, and two had presenting complaints of mild exercise intolerance. Concurrent congenital heart disease was diagnosed in four of the dogs including pulmonary valve stenosis (n = 2), mitral and tricuspid valve dysplasia (n = 2), and restrictive perimembranous ventricular septal defect (n = 1). Following comprehensive transthoracic echocardiography, ECG-gated CTA was acquired under conscious sedation to characterize ASD anatomy including rim tissue and surrounding structures to determine candidacy for device occlusion. A reconstructed model was viewed with three-dimensional glasses in a mixed reality environment displayed as a stereoscopic object able to be rotated in 360° on a desktop monitor. Inadequate rim tissue was demonstrated in four dogs. Device occlusion was recommended in one dog and successfully performed with a hybrid procedure. Subsequently, balloon pulmonary valvuloplasty was performed. The dog was clinically doing well at 9.1 years of age. The remaining four dogs were clinically doing well (three) or had mild exercise intolerance reported (one) at 4.0-11.5 years of age. This case series demonstrates the utility of stereoscopic models and an interactive mixed reality viewer to assess procedural candidacy for device occlusion in dogs with ASD.