Echocardiographic and Angiographic Comparison of Ductal Dimensions in Dogs with Patent Ductus Arteriosus

Background: Transcatheter occlusion of patent ductus arteriosus (PDA) is a minimally invasive treatment option in dogs. Device selection based on appropriately acquired PDA dimensions and morphology can minimize procedural complications, including minimizing residual ductal flow and inappropriate embolization. Hypothesis: Transesophageal echocardiographic (TEE) derived minimum ductal diameter measurements would most accurately reflect angiographic measurements. Color Doppler (CD) TEE and transthoracic echocardiographic (TTE) ductal measurements would overestimate two-dimensional (2D) measurements. Animals: Fifteen client-owned dogs with PDA. Methods: PDA dimensions obtained with angiography, 2D and CD TTE, 2D and CD TEE from the right and left views were prospectively evaluated. Results: PDA dimensions were measured by using TEE most closely approximated angiographic measures. CD TTE and TEE frequently overestimated angiographic measures of minimum ductal diameter. TEE accurately identified a type III (tubular) PDA morphology in 1 dog. Fourteen of 15 dogs were determined to have hemodynamically significant reductions in left to right shunting documented by a first-pass nuclear angiocardiographic ratio of pulmonary to systemic blood flow ±1.2 and trivial (n = 3) to no (n = 11) CD TTE flow at approximately 1 month after PDA occlusion. Conclusions: TEE provided accurate anatomic information regarding PDA morphology and closely approximated angiographic ductal dimensions while aiding in both coil deployment and confirmation of intra-operative ductal closure.