title: Robot-assisted real-time magnetic resonance image-guided transcatheter aortic valve replacement.
abstract: BACKGROUND
  Real-time magnetic resonance imaging (rtMRI)-guided transcatheter aortic valve replacement (TAVR) offers improved visualization, real-time imaging, and pinpoint accuracy with device delivery. Unfortunately, performing a TAVR in a MRI scanner can be a difficult task owing to limited space and an awkward working environment. Our solution was to design a MRI-compatible robot-assisted device to insert and deploy a self-expanding valve from a remote computer console. We present our preliminary results in a swine model.
  
  
  METHODS
  We used an MRI-compatible robotic arm and developed a valve delivery module. A 12-mm trocar was inserted in the apex of the heart via a subxiphoid incision. The delivery device and nitinol stented prosthesis were mounted on the robot. Two continuous real-time imaging planes provided a virtual real-time 3-dimensional reconstruction. The valve was deployed remotely by the surgeon via a graphic user interface.
  
  
  RESULTS
  In this acute nonsurvival study, 8 swine underwent robot-assisted rtMRI TAVR for evaluation of feasibility. Device deployment took a mean of 61 ± 5 seconds. Postdeployment necropsy was performed to confirm correlations between imaging and actual valve positions.
  
  
  CONCLUSIONS
  These results demonstrate the feasibility of robotic-assisted TAVR using rtMRI guidance. This approach may eliminate some of the challenges of performing a procedure while working inside of an MRI scanner, and may improve the success of TAVR. It provides superior visualization during the insertion process, pinpoint accuracy of deployment, and, potentially, communication between the imaging device and the robotic module to prevent incorrect or misaligned deployment.
authors.affiliation: Cardiothoracic Surgery Research Program, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Md.
authors.forename: Justin G
authors.initials: JG
authors.lastname: Miller
authors.affiliation: Cardiothoracic Surgery Research Program, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Md.
authors.forename: Ming
authors.initials: M
authors.lastname: Li
authors.affiliation: Cardiothoracic Surgery Research Program, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Md.
authors.forename: Dumitru
authors.initials: D
authors.lastname: Mazilu
authors.affiliation: Cardiothoracic Surgery Research Program, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Md.
authors.forename: Tim
authors.initials: T
authors.lastname: Hunt
authors.affiliation: Cardiothoracic Surgery Research Program, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Md. Electronic address: horvathka@mail.nih.gov.
authors.forename: Keith A
authors.initials: KA
authors.lastname: Horvath
mesh_terms: D000818:Animals; D001021:Aortic Valve / Q000601:surgery*; D005240:Feasibility Studies; D006350:Heart Valve Prosthesis; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D019060:Minimally Invasive Surgical Procedures / Q000379:methods; D023421:Models, Animal; D061646:Operative Time; D065287:Robotic Surgical Procedures / Q000379:methods*; D012680:Sensitivity and Specificity; D013552:Swine; D065467:Transcatheter Aortic Valve Replacement / Q000379:methods*
keywords: real-time magnetic resonance image; robot-assisted transcatheter aortic valve replacement; swine animal model