Transcatheter valve implantation: damage to the human aorta after valved stent delivery system exposure--an in vitro study.

Transcatheter heart valve implantation can be performed transapically and transfemorally. The transfemoral way to the aortic valve is significantly longer than the transapical one. The aim of this study was to analyse the intima of 15 human aortas after the deployment of different conventional valved stent delivery systems. Fifteen human aortas have been analysed (77 ± 8.4 years). These aortas were preserved with formalin and explanted from the common iliac arteries to the ascending aorta. After protocolling all relevant vascular parameters, the deployment force of different conventional valved stent delivery systems was analysed. After that, the intima was closely investigated by endoscopy. The deployment force of the old catheter was not different from the actual system. The endoscopic investigation revealed significant intimal damages in all parts of the aorta after deployment of the delivery system. This study demonstrated that the passage to the aortic valve can result in significant intimal damage regardless of the used deployment catheter. Efforts are necessary to lower the profile of the deployment devices to increase their flexibility. The intima of the aorta and possible damage have to get back into the physicians' focus to avoid possible late aortic complications.

Transcatheter aortic valve replacement: transapical resection of the aortic valve in vivo.

The resection of pulmonary valves has already been demonstrated in an experimental beating-heart model. The aim of this study was to analyse the transapical laser-assisted resection of aortic valves in an in vivo porcine model in a non-beating heart. The resection was performed in a porcine model (n = 10) using a Thullium:YAG laser. After establishing a standard extracorporeal circulatory support, the aortic valve isolation chamber (AVIC) system was inserted transapically. The resection of the aortic leaflets was carried out step-by-step in the arrested heart. The AVIC implantation, the resection process, and the gross anatomy of intracardiac lesions were analysed. The procedure for installing the AVIC took 5.8 ± 1.5 min. A sealed chamber was achieved in 9/10 cases. The resection of the valves was performed in 8/10 and completed in 7/10 cases. The resection took, on average, 7.4 ± 2.7 min/cusp. In 9/10 cases, the sealing was sufficient. Gross anatomy and histological analysis demonstrated only superficial damage to the surrounding tissue. In this study, the in vivo on-pump isolation of the left ventricular outflow tract and the laser resection of the native aortic valve could be demonstrated successfully. Nevertheless, this model is the next step towards a beating-heart resection of the aortic valve using the isolation chamber.