Seminar 2006 12 06 MRI Cardiac Surgery
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CISST ERC Seminar
MRI Guided Cardiac Surgery
Date: Wednesday, December 6, 2006
Time: 12:00pm, Lunch will be served before the seminar.
Place: Maryland Hall 110
Speaker: Keith Horvath 
Title: MRI Guided Cardiac Surgery
Presentation slideshow: PDF, 6MB ( info )
Abstract
Purpose
Percutaneous techniques to replace the aortic valve have achieved a modicum of success. The principal limitations are detailed visualization and durable prostheses. The feasibility of utilizing real-time magnetic resonance imaging to provide precise anatomic detail and visual feedback to implant a proven bioprosthesis has not been reported.
Description
Twelve domestic pigs were anesthetized and via a minimally invasive approach using real-time MRI guidance underwent aortic valve replacement. This was accomplished on the beating heart using a commercially available bioprosthesis (Toronto SPV, St. Jude). MR imaging was used to precisely identify the anatomic landmarks of the aortic annulus, coronary artery ostia, and the mitral valve leaflets. Additional intraoperative perfusion, flow velocity and functional imaging were used to confirm adequacy of placement and function of the valve.
Evaluation
Under real-time MR imaging, multiple oblique planes were prescribed to delineate the anatomy of the native aortic valve and left ventricular outflow track. Enhanced by the use of an active marker wire, this imaging allowed correct placement and orientation of the valve. Via a transapical approach a series of bioprosthetic aortic valves (21-25mm) were inserted. The time to implantation after the placement of the trocar to deployment of the valve was less than ninety seconds. The average procedure duration was less than forty minutes. In addition to anatomic confirmation of adequate placement of the prosthetic valve in relation to the aortic annulus and the coronary arteries, functional confirmation of the valve and left ventricle was also obtained with MR imaging. Intraoperative perfusion scanning documented adequacy of myocardial blood flow after valve placement. Phase velocity confirmed adequate opening of the prosthetic valve leaflets and lack of valvular or paravalvular regurgitation. Avoidance of injury to the mitral valve or subvalvular apparatus was also confirmed and readily assessed.
Conclusions
Real-time MR imaging provides excellent anatomic detail and intraoperative assessment that permits placement of durable valve prostheses on the beating heart without the limitations of percutaneous approaches.
Bio
Keith Horvath is Chief, Cardiothoracic Surgery at Suburban Hospital as well as Director, Cardiothoracic Surgery Research for the National Heart, Lung, Blood Institute (NHLBI) at the National Institutes of Health (NIH) and an affiliate with Johns Hopkins Medical Center. He assumed this position after being an Associate Professor of Surgery at Northwestern University, Chicago Illinois. Trained in general and cardiothoracic surgery at the Brigham and Women’s Hospital, Dr. Horvath is a graduate of the University of Chicago, Pritzker School of Medicine.
As Chief, Cardiothoracic Surgery he is committed to the successful design and outcome of the NIH Heart Center at Suburban Hospital. He leads a staff of 43 dedicated cardiothoracic surgery representatives who are experts in various methodologies of patient care. Although his hospital practice is still in the developmental phase its operation is seamless.
As Director, Cardiothoracic Surgery Research Program at the NIH, Dr. Horvath’s organization is a three part surgical program to scientifically investigate cellular/molecular biology, biomechanics, and xenotransplantation results within vivo models. His NIH team includes 3 staff scientist, 2 fellows, and 1 biomechanical engineer.
Finally, Dr. Horvath has performed over fifteen hundred cardiac surgeries. He has authored and coauthored over one hundred publications and presented over one hundred presentations.