Development of a Transcatheter Cardiac Leaflet Enhancer to Treat Functional Mitral Regurgitation
Author(s)
Sreerangathama Suresh, Kirthana
Advisor(s)
Editor(s)
Collections
Supplementary to:
Permanent Link
Abstract
Functional mitral regurgitation (FMR) is a common heart valve lesion seen in heart failure (HF) patients and it has been shown to worsen the HF progression. FMR is often treated by either repair or replacement of the valve when patients undergo concomitant coronary bypass surgery. However, most HF patients are deemed as too high-risk for such surgeries due to their poor health conditions. Therefore, minimally invasive transcatheter technologies are in need for such patients. MitraClip (Abbott Laboratories) is currently the only FDA approved transcatheter repair technology that treats FMR by approximating the leaflet edges together creating a double orifice valve similar to surgical Edge-to-Edge (EE) repair. Though effective in some cases, the technology fails to adequately treat FMR and disturbs the native valve dynamics resulting in poor long-term durability. To address the need of durable repair, I hypothesized that augmenting the valve leaflet at the regurgitant site using a light-weight implant would provide leaflet extension and cover the regurgitant gap in systole; and the implant would move along with the leaflet in diastole to allow unrestricted inflow. To test the hypothesis, in aim1, I developed a cardiac leaflet enhancer implant (CARLEN), which is miniature fabric covered nitinol implant, that focally augments the native leaflet when attached. A steerable delivery system was also developed for transcatheter deployment of CARLEN under image guidance. Both implant and delivery system were iteratively designed, and feasibility of the concept was validated in a swine model. In aim2, the functionality of CARLEN in correcting FMR and its impact on mitral valve geometry and hemodynamics were assessed in an ex-vivo model. The ex-vivo studies demonstrated that CARLEN can treat regurgitation as effective as EE repair and unlike EE, CARLEN neither increased the diastolic pressure gradient nor decreased the valve opening area. Lastly in aim3, the efficacy of CARLEN was validated in an acute swine model of MR; Healing and integration of the implant with the native tissue were also assessed in a chronic swine model, which demonstrated that the implant was completely encapsulated by a neo-endocardial layer providing a permanent leaflet extension. Completion of this work has resulted in the development of a novel transcatheter mitral valve repair system that can treat FMR effectively without disturbing the native valve apparatus. This work provides a premise for future chronic efficacy studies and further clinical translation to patients.
Sponsor
Date
2022-04-29
Extent
Resource Type
Text
Resource Subtype
Dissertation