Only a couple years ago I attended ACC.12 in Chicago, excited to hear about the latest results from the Partner series of trials looking at the use of transcatheter aortic valve replacement (TAVR) for the treatment of aortic stenosis. While the devices had been in use in Europe since 2008, this was the first randomized data to compare the treatment versus medical therapy in the surgically ineligible, and more ambitiously, to investigate TAVR as an alternative to surgical replacement of the valve. The discussion at the time focused on proving the efficacy of the therapy, its initial foray into the market, whether it was a viable replacement for open surgery, and concerns around procedural stroke risk.
What a difference a couple of years makes! The Partner and CoreValve pivotal trials in the US firmly established the viability of TAVR, changing the discussion from extreme risk and moving it towards how low can we go in surgically eligible patients. Additionally, improvements in our understanding of the procedure methodology and patient selection as well as advances in devices continue to lead to better procedure results. At this year's EuroPCR conference, it felt as if TAVR had lost its newness, and was well on its way to becoming routine (the parade of new valve iterations did still have that buzz-level feeling, with multiple manufacturers touting increasingly excellent results).
Moving beyond the aortic valve, the buzz was definitely apparent in the goal to develop therapies to treat the mitral valve and its related dysfunctions (the tricuspid and pulmonary positions also had a few nods). The mitral space represents a potentially larger, but more difficult population to develop products for and treat with transcatheter technologies. Surgical repair of the valve, the preferred intervention, requires multiple components to be treated and represents less of a one-size-fits-all approach compared to aortic valve replacement.
However, the success in the aortic position has renewed physicians' and manufacturers' beliefs that we can conquer the challenges of the mitral space as well. Despite the difficulties in developing a device for the mitral space (currently only one therapy, the MitraClip, has shown commercial success), the excitement surrounding the presentation of very early clinical stage devices was palpable. The biggest buzz was for alternatives to transcatheter repair, namely, transcatheter replacement valves designed for the mitral space. This is, however, a very long-term opportunity because only a handful of patients have undergone valve implantation, so expect the buzz to continue to grow with successive conferences as more data become available.