Building foundations for transcatheter intervascular anastomoses: 3D anatomy of the great vessels in large experimental animals.

Objectives: To provide comprehensive illustrations of anatomy of the relevant vessels in large experimental animals in an interactive format as preparation for developing an effective and safe transcatheter technique of aortopulmonary and bidirectional cavopulmonary intervascular anastomoses.

Methods: Computed tomographic angiographic studies in two calves and two sheep were used to prepare 3D reconstructions of the aorta, pulmonary arteries, and caval and pulmonary veins. Based on these reconstructions, computer simulations of the creation of stent-enhanced aortopulmonary and bidirectional cavopulmonary anastomoses were made.

Results: We observed the following major anatomical features: (i) caudal course of the main pulmonary artery and its branches with the proximal right pulmonary artery located immediately caudal to the aortic arch, and with the central left pulmonary artery lying at a substantial distance from the descending aorta; and (ii) the distal right pulmonary artery is located dorsal to the right atrium and inferior caval vein at a substantial distance from the superior caval vein. Animations showed creation of transcatheter analogues of Waterston's and Potts' aortopulmonary shunts through placement of a covered spool-shaped stent, and the transcatheter creation of bidirectional Glenn's cavopulmonary anastomosis, by placement of a long covered trumpet-shaped stent.

Conclusions: There are considerable differences in vascular anatomy between large experimental animals and humans. Given the need to elaborate new transcatheter techniques for intervascular anastomoses in suitable animal models before application to human, it is crucial to take these anatomical differences into account during testing and optimization of the proposed procedures.