A Retrievable Aortic Drug Delivery Stentgraft To Create A Porcine Model Of Thoracic Aneurysms

Objectives: Murine models present limitations for the study of aortic aneurysm due to disparate hemodynamics from humans, small size and the necessity for open surgery and aortic clamping to apply otherwise toxic aneurysmogenic enzymes. We have developed a retrievable chambered stentgraft that can isolate aortic wall and more importantly restrict enzyme to only the anterior aorta. Figure 1 shows a posterior central lumen (CL) that preserves distal perfusion while excluding posterior spinal cord branches, and an outer chamber (OC) delivers drug to anterior aortic wall. We hypothesized that a Retrievable Aortic Drug Delivery Stentgraft (RADDS) could deliver enzymes directly to the aortic wall to create a porcine model of thoracic aortic aneurysms (TAA). Methods: The RADDS stentgraft scaffold was laser cut from nitinol, shapeset, and covered in polymer. A permanent delivery wire was affixed distally, and a perfusion cannula to the OC. The stent was delivered from percutaneous femoral access to the thoracic aorta in a porcine model (n=6). Following angiography, an enzyme cocktail (elastase/collagenase) was infused to the OC then aspirated and the stent retrieved via sheath advancement. Results: The RADDS achieved angiographic isolation of the anterior aortic wall from both the circulation and spinal cord. Distal perfusion was preserved through the CL and femoral arterial pressures were unchanged after stent placement (p = 0.88). Spinal paresis was not observed. All animals developed acute aortic degeneration ranging from 1 hour to 6 weeks post-treatment with H&E histology reflecting deteriorated aortic media with specific disruption of elastic lamina. Conclusions: The RADDS allowed endovascular delivery of systemically toxic agents directly to the aortic wall for creation of TAA. These findings herald a novel approach to isolate potentially toxic therapies to the aortic wall and may offer future opportunities to instead deliver aneurysm treating therapies.