Search

Purpose: In a recent study our group established an acute animal model of percutaneous pulmonary valve replacement using self-expanding nitinol stents. The present study was performed to evaluate these valved stents over a 3-month period. Description: Bovine jugular xenografts were sutured into nitinol stents. Transfemoral implantation in the pulmonary position using a modified commercially available application device (with a 22-French outer diameter) was evaluated in 9 sheep. Evaluation: Two sheep died shortly after successful valved stent implantation due to internal venous hemorrhage. Another 1 sheep died 2.5 months after the procedure due to vegetations on the neovalve leading to subtotal stenosis. All other animals survived the 3-month study time (n = 6). An orthotopic pulmonary valved stent position was achieved in 4 animals and a supravalvular position in 1. During the deployment procedure, rhythm disturbances occurred in all animals, and mean arterial blood pressure dropped from 83.9 ± 26.0 mm Hg to 68.3 ± 22.3 mm Hg (p = 0.006) (n = 5). The peak-to-peak transvalvular gradient was 5.1 ± 4.0 mm Hg initially (n = 5), and 3.6 ± 1.6 mm Hg at follow-up (n = 5). Three-month angiographic and echocardiographic follow-up confirmed competent neovalves without paravalvular leakages. Conclusions: After 3 months of implantation, percutaneously implanted memory nitinol valved stents demonstrated good function in the sheep. [Copyright &y& Elsevier]

Objective: : To improve the outcome of percutaneous valve replacement in aortic stenosis endovascular resection of calcified aortic valves will be necessary. In this study different sealing methods were evaluated. The focus of this research was feasibility and mechanical functionality in human anatomy., Methods: : The aortic valve isolation chamber (AVIC) is a catheter-based system to seal the aortic valve during resection, and was installed antegrade and retrograde. Firstly, AVIC was inserted antegrade via the cardiac apex in human postmortem models (n = 2), and secondly in porcine in vivo models under extra corporeal circulation (n = 5). Endoscopic inspection of the valve was recorded. AVIC was installed via a port system through the descending aorta. Micro- and macropathologies were performed., Results: : AVIC transapical deployment in the two human models took 3 and 4 minutes respectively and 2.2 ± 1.3 minutes in average in the porcine model. From the descending aorta, the deployment took 9.3 ± 5.5 minutes. Fluoroscopy and macroscopy demonstrated sealed chambers. Microscopic and histologic analysis demonstrated no profound damages of the surrounding tissue., Conclusion: : This study demonstrates the feasibility of transapical and retrograde endovascular sealing of the aortic valve in vitro and in vivo in nonbeating hearts.

An increasing number of centers are reusing PTCA catheters even though manufacturers warrant single use only. This prospective bench laboratory trial addresses the quality of PTCA balloon catheters after up to three resterilization cycles in order to determine whether a larger trial is warranted to discern whether catheters should be reused. Forty PTCA catheters from two different manufacturers (nominal diameters 1.5 and 3.0 mm) were taken from the shelf. An independent institute tested mechanical properties such as burst pressure, nominal diameter, crossing profile, and balloon surface. The crossing profile increased by 22.5%-39.2% with no additional deterioration after repeated sterilizations. The nominal diameter either increased or decreased by a maximum of 47%. In all 1.5 mm balloons, the burst pressure remained above the manufacturers' values, whereas in the 3.0 mm balloons, the value dropped below the rated burst pressure in 40%-50% of the trials. In conclusion, in both catheter types analyzed, reuse was associated with a considerably worse quality, which puts in question their routine clinical use., (Copyright 2003 Wiley-Liss, Inc.)