Following supine bicycle exercise testing to assess eligibility, the eligible patients are randomized to the treatment or control group. All patients will be sedated, and both treatment and control arm patients will undergo placement of a femoral venous access sheath after randomization. Patients randomized to the treatment arm will undergo a fluoroscopically and intra-cardiac echocardiography (ICE), or transesophageal echocardiography (TEE) guided trans-septal puncture and IASD System II implant procedure. Patients randomized to the control arm will undergo ICE from the femoral vein or TEE for examination of the atrial septum and left atrium. Patients will be evaluated at pre-specified time intervals and followed for 5 years. All patients will be unblinded after the 24 month follow up visit. Patients randomized to the control arm will be allowed to cross-over to the treatment arm at ≥ 24 months post-control procedure provided patient selection criteria are met at that time. Cross-over patients will then be followed for 5 years after cross-over.
The Portico NG Approval study will be conducted as a prospective, multi-center, international, single-arm investigational study. High or extreme risk patients with symptomatic, severe native aortic stenosis who are determined by an independent subject selection committee to meet eligibility criteria for Portico NG Transcatheter Aortic Heart Valve implantation will undergo Portico™ NG Valve implantation via a transfemoral or alternative access approach according to the site's anesthesia protocol for TAVR (transcatheter aortic valve replacement) procedure.