Small Animal Surgery Resident North Carolina State University Raleigh, North Carolina
Feasibility of Thoracoscopic Attenuation of the Azygos Vein as a Model for Portoazygos Shunts: A Canine Cadaveric Study. Carroll KA1, Dickson RE2, Scharf VF1. 1North Carolina State University, Department of Clinical Sciences, Raleigh, NC; 2Washington State University, Department of Veterinary Clinical Sciences, Pullman, WA.
Thoracoscopic access to portoazygos (PA) shunts would provide a minimally invasive alternative for shunt attenuation. The objectives of this study were to evaluate the feasibility of thoracoscopic placement of three vascular attenuation devices using the azygos vein as a model for PA shunts and to describe this approach in small breed dogs. We hypothesized that thoracoscopic placement of ameroid ring constrictors (ARCs) and cellophane bands on the caudal azygos vein via a novel thoracoscopic approach would be feasible. Cadavers were placed in sternal recumbency and three thoracoscopic ports were established in the caudodorsal right hemithorax. The caudal azygos vein was thoracoscopically isolated along three adjacent segments bordered by four intercostal arteries. Three attenuation devices (coated cellophane, uncoated cellophane, and a 5 mm ARC) were thoracoscopically placed around one segment in each dog. Ability to place the device, time required for placement, endoscopic clip configuration, and complications were recorded. Median dog weight was 7.7 kg (range, 1.8–11 kg). All attenuation devices were successfully placed thoracoscopically in all cadavers. No difference was detected in time required for placement between the ARC, and coated and uncoated cellophane (range, 2.3–33.8 minutes; P = 0.830). This study demonstrates the feasibility of thoracoscopic ARC and cellophane placement using a cadaveric azygos vein model to simulate PA shunts. Limitations include the use of a cadaveric model to simulate PA shunts in live dogs. The results of this study justify clinical investigation of thoracoscopic shunt attenuation in dogs with PA shunts.