In Mitral Regurgitation (MR), the diseased valve permits backflow of blood, threatening overall cardiac function. MR can result from a variety of causes. In light of an ever-expanding field of options for surgical intervention, the CFM Lab is working to better understand the mechanics underlying MR and its treatment. Our findings directly support industrial and clinical efforts to improve device design and to optimize patient-repair selection.
We develop novel tools to measure strains and forces in and around the mitral valve. In one ongoing study, our custom technology is helping to explain clinical failure of a common MR repair technique known as ring annuloplasty (left). By attaching small measurement tools to the ring and implanting in a live ovine subject (right), we can quantify forces acting on individual sutures (bottom). Our findings will inform surgical techniques and future ring designs to help minimize risk of ring dehiscence (breakaway from the valve). Left panel illustration courtesy of Dr. Alain Carpentier.
We also create customized, cutting-edge simulators and data acquisition techniques to run tightly controlled bench-top tests on mitral valve structure and function. The simulator can be used to test clinical repairs, provide constraints for the design of medical devices, inform computational models, and inform surgical decision-making. Above, the Cylindrical Modular Left Heart Simulator houses an ovine mitral valve between chambers simulating the heart’s left atrium and ventricle.
In addition to pressure, flow, and local force measurements, our simulator’s latest advancements enable use of advanced imaging techniques. Shown above are two such cases: dynamic 3D ultrasound (left) and Micro Computed Tomography (right). These directly feed into computational models that we hope will revolutionize patient-specific surgical planning in the near future.
- Pierce EL, Siefert AW, Paul DM, Wells SK, Bloodworth CH, Takebayashi S, Aoki C, Jensen MO, Gillespie MJ, Gorman RC, Gorman JH, Yoganathan AP. How Local Annular Force and Collagen Density Govern Mitral Annuloplasty Ring Dehiscence Risk. Ann Thorac Surg. 2016 Aug; 102: 518-26.
- Toma M, Bloodworth CH, Einstein D, Pierce EL, Cochran RP, Yoganathan AP, Kunzelman KS. High-resolution subject-specific mitral valve imaging and modeling: experimental and computational methods. Biomech Model Mechanobiol. 2016 Apr; [epub ahead of print].
- Pierce EL, Bloodworth CH, Naran A, Easley TF, Jensen MO, Yoganathan AP. Novel Method to Track Soft Tissue Deformation by Micro-Computed Tomography: Application to the Mitral Valve. Ann Biomed Eng. 2016 Jul; 44(7): 2273-81.
- Siefert AW, Rabbah JPM, Koomalsingh KJ, Touchton SA, Saikrishnan N, McGarvey JR, Gorman RC, Gorman JH, Yoganathan AP. In Vitro Mitral Valve Simulator Mimics Systolic Valvular Function of Chronic Ischemic Mitral Regurgitation Ovine Model. Ann Thorac Surg. 2013 Mar; 95: 825-30.
- Rabbah JPM, Siefert AW, Bolling SF, Yoganathan AP. Mitral valve annuloplasty and anterior leaflet augmentation for functional ischemic mitral regurgitation: Quantitative comparison of coaptation and subvalvular tethering. J Thorac Cardiovasc Surg. 2014 Oct; 148(4): 1688-93.