Percutaneous MR guided direct left atrial access to deliver large interventional devices

Background Transcatheter aortic valves have benefitted from device miniaturization and in-situ assembly to reduce delivery system caliber and enable trans-vascular delivery. In contrast, investigational transcatheter mitral prostheses are bulky devices that require large caliber access ports. Trans-apical delivery is undesirable because of increased morbidity associated with rib spreading, closure site bleeding and impact on left ventricle (LV) function. Trans-septal delivery is challenging because of the acute angle required to reach the mitral valve. A ‘straight shot’ to the mitral valve (Fig 1A) that does not violate the LV myocardium is preferable, both in terms of device engineering and patient outcome. We hypothesized that with realtime MR guidance and by deflating a lung, it is possible to access the left atrium (LA) directly through the posterior chest wall, and close the access port using off-the-shelf nitinol devices.