Surgical techniques for aortic valve xenotransplantation

Background Heart valve replacement in neonates and infants is one of the remaining unsolved problems in cardiac surgery because conventional valve prostheses do not grow with the children. Similarly, heart valve replacement in children and young adults with contraindications to anticoagulation remains an unsolved problem because mechanical valves are thrombogenic and bioprosthetic valves are prone to early degeneration. Therefore, there is an urgent clinical need for growing heart valve replacements that are durable without the need for anticoagulation. Methods A human cadaver model was used to develop surgical techniques for aortic valve xenotransplantation. Results Aortic valve xenotransplantation is technically feasible. Subcoronary implantation of the valve avoids the need for a root replacement. Conclusion Aortic valve xenotransplantation is promising because the development of GTKO.hCD46.hTBM transgenic pigs has brought xenotransplantation within clinical reach.

Feasibility of fresh frozen human cadavers as a research and training model for endovascular image guided interventions

Objective To describe the feasibility of a fresh frozen human cadaver model for research and training of endovascular image guided procedures in the aorta and lower extremity. Methods The cadaver model was constructed in fresh frozen human cadaver torsos and lower extremities. Endovascular access was acquired by inserting a sheath in the femoral artery. The arterial segment of the specimen was restricted by ligation of collateral arteries and, in the torsos, clamping of the contralateral femoral artery and balloon occlusion of the supratruncal aorta. Tap water was administered through the sheath to create sufficient intraluminal pressure to manipulate devices and acquire digital subtraction angiography (DSA). Endovascular cannulation tasks of the visceral arteries (torso) or the peripheral arteries (lower extremities) were performed to assess the vascular patency of the model. Feasibility of this model is based on our institute’s experiences throughout the use of six fresh frozen human cadaver torsos and 22 lower extremities. Results Endovascular simulation in the aortic and peripheral vasculature was achieved using this human cadaver model. Acquisition of DSA images was feasible in both the torsos and the lower extremities. Approximately 84 of the 90 target vessels (93.3%) were patent, the remaining six vessels showed signs of calcified steno-occlusive disease. Conclusions Fresh frozen human cadavers provide a feasible simulation model for aortic and peripheral endovascular interventions, and can potentially reduce the need for animal experimentation. This model is suitable for the evaluation of new endovascular devices and techniques or to master endovascular skills.

Radiologic Analysis of Balloon Sinuplasty in a Human Cadaver Model: Observed Effects on Sinonasal Anatomy

Background Balloon sinuplasty is increasingly used in the outpatient clinic for treatment of chronic rhinosinusitis, but radiologic analysis of its effects on sinonasal anatomy is largely uncharacterized in the known literature. Objective The purpose of this study is to examine the anatomic effects of balloon sinuplasty in a cadaveric model. Methods Five fresh cadaver heads underwent sequential endoscopic balloon dilation of maxillary ostia, frontal recess outflow tracts, and sphenoid ostia bilaterally by fellowship-trained rhinologists. Pre- and post-procedural CT imaging was obtained. CT scans were imported into Mimics™ software and sinonasal anatomy was analyzed systematically. Results Visual confirmation of balloon dilation was achieved in all 3 sites bilaterally in each cadaver. Radiologic analysis demonstrated that the frontal sinus outflow tract was appropriately dilated 60% (6/10 sites) of the time while the agger was inadvertently dilated 30% of the time (3/10). The sphenoid os was successfully dilated 70% (7/10 sites) of the time. In two cases, a posterior sphenoethmoid (Onodi) cell was dilated instead of the sphenoid. Successful dilation of maxillary os was noted 60% of the time (6/10 sites). No significant change in maxillary os was noted after balloon dilation. Normal middle turbinates were significantly medialized following balloon dilation 75% (6/8 sites) of the time. Conclusions While the goal of balloon sinuplasty is to improve natural sinonasal drainage by dilating existing outflow tracts, as evidenced by radiologic evaluation the procedure appears not to achieve this in all cases, while occasionally creating unintended changes in sinonasal anatomy as well. These unrecognized changes in anatomy may be responsible for the post-procedure change in symptomatology that some patients experience.