Polytetrafluoroethylene leaflet extensions for aortic valve repair.

(Leipzig, Germany): I commend you for your courage in using a new product designed for a completely different purpose, but which works well. My first question is, what are your indication criteria because you have patients with a moderate stenosis and moderate insufficiency, a mean of 1.8 and a mean gradient of 54? Dr Nosál': Typically our patients have a mixed aortic valve pathology, so the median aortic insufficiency at the time of indication is around 2 with a gradient of 55. If we have a patient with an isolated stenosis, the indication is based on the gradient across the aortic valve and on the progression of the left ventricu-lar hypertrophy. On the other hand, in a patient with pure aortic insufficiency, the indication is based on the amount of insufficiency and the progression of left ventricular end systolic diameter on echocardiographic measurement. Dr Kostelka: Do you have any proof that the mechanical characteristics of this very tiny, awkward 1 mm membrane are superior to autologous pericar-dium? Did you test it in vitro in any way? Dr Nosál': We did not test this valve in vitro, but tests have been performed. From personal communications with people who were involved in testing those PTFE valves, we know that this is quite a stress-resistant material, this PTFE membrane. But those were pure PTFE valves. We have previously had a pretty large experience with around 35 patients who underwent this type of operation with glutaraldehyde-treated pericardium, so we can compare with this group, but this group is still a little bit small. Dr Kostelka: Do you expect different behaviour in the aortic position under systemic pressure above 100 in comparison to the right side? There are well-known papers from one group in Florida, and another group in Japan, with a trileaflet pulmonary valve reconstruction, or bileaflet, because they are under a pressure of 22 mm and there is 122. Did you see any changes in the mobility of the cusp during the time of the follow-up? Dr Nosál': I think this situation is a little bit different than the complete PTFE valve in the pulmonary position because, as you saw in the video, a significant portion of the valve remains in situ, so we just extend the leaflets. And as for the echocardiographic follow-up, we do not have a special method to assess the mobility of the leaflets. Honestly, it is more difficult …