Aortic stenosis is one of the most common cardiology diseases. If untreated, symptomatic aortic stenosis rapidly leads to death. Most of the time, this disease affects old fragile people for whom conventional surgery is countered or very risky. That is why Trans aortic valve implantation has been developed since 2002, first to treat rejected patients from conventional surgery, then to treat high surgical risk patients and nowadays probably intermediate surgical risk patient. Indeed, thanks to prodigious technical and human progress, procedure induced complication have clearly decreased. But TAVI related complications are still recurrent and the investigators are searching a way to decrease them.