Objective: Emerging off-pump beating heart valve repair techniques offer patients less invasive alternatives for mitral valve (MV) repair. However, most of these techniques rely on the limited spatial and temporal resolution of transesophageal echocardiography (TEE) alone, which can make tool visualization and guidance challenging.
Methods: Using a magnetic tracking system and integrated sensors, we created an augmented reality (AR) environment displaying virtual representations of important intracardiac landmarks registered to biplane TEE imaging. In a porcine model, we evaluated the AR guidance system versus TEE alone using the transapically delivered NeoChord DS1000 system to perform MV repair with chordal reconstruction.
Results: Successful tool navigation from left ventricular apex to MV leaflet was achieved in 12 of 12 and 9 of 12 (P = 0.2) attempts with AR imaging and TEE alone, respectively. The distance errors of the tracked tool tip from the intended midline trajectory (5.2 ± 2.4 mm vs 16.8 ± 10.9 mm, P = 0.003), navigation times (16.7 ± 8.0 seconds vs 92.0 ± 84.5 seconds, P = 0.004), and total path lengths (225.2 ± 120.3 mm vs 1128.9 ± 931.1 mm, P = 0.003) were significantly shorter in the AR-guided trials compared with navigation with TEE alone. Furthermore, the potential for injury to other intracardiac structures was nearly 40-fold lower when using the AR imaging for tool navigation. The AR guidance also seemed to shorten the learning curve for novice surgeons.
Conclusions: Augmented reality–enhanced TEE facilitates more direct and safe intracardiac navigation of the NeoChord DS tool from left ventricular apex to MV leaflet. Tracked tool path results demonstrate fourfold improved accuracy, fivefold shorter navigation times, and overall improved safety with AR imaging guidance.
From the *Division of Cardiac Surgery, Department of Surgery, †Robarts Research Institute, Western University; ‡Canadian Surgical Technologies and Advanced Robotics; §Departments of Medical Imaging, ∥Anaesthesia, ¶Division of Cardiology, Department of Medicine, Western University, London, ON Canada; and #Mayo Clinic, Rochester, MN USA.
Accepted for publication August 29, 2012.
Funding for this work was provided by Canadian Foundation for Innovation (20994), the Ontario Research Fund (RE-02-038), and the Canadian Institutes of Health Research (179298). Funding for the animal laboratory study was received from NeoChord, Inc., Eden Prairie, MN USA.
Presented the Young Investigator Award at the Annual Scientific Meeting of the International Society for Minimally Invasive Cardiothoracic Surgery, May 30–June 2, 2012, Los Angeles, CA USA.
Disclosures: Gerard Guiraudon has a licensing agreement for GUCI, with Valve Xchange Inc., in Aurora, Denver, CO USA, and is a Special Medical Advisor with the company. Richard C. Daly, MD, is a consultant at NeoChord, Inc., Eden Prairie, MN USA. Bob B. Kiaii, MD, is a consultant at Medtronic, Inc., Minneapolis, MN USA. John Moore, MA, MSc, Terry Peters, PhD, FIEEE, Daniel Bainbridge, MD, David McCarty, MB, BCh, MRCP, Gerard M. Guiraudon, MD, Chris Wedlake, BSc, Pencilla Lang, BEng, Martin Rajchl, MSc, Maria E. Currie, MD, declare no conflict of interest.
Address correspondence and reprint requests to Michael W.A. Chu, MD, B6-106 University Hospital, London Health Sciences Centre, 339 Windermere Rd, PO Box 5339, London, ON Canada N6A 5A5. E-mail: firstname.lastname@example.org.