Abstract

Introduction : Nowadays micro-invasive procedures (off-pump, beating heart) for mitral valve repair (MVRe) are abruptly expanding with the potential to be adopted as a valuable alternative to surgery. In the present manuscript, the Authors review the available technologies intended to treat mitral regurgitation (MR) through transapical approach, including annuloplasty and chordal repair options.
Annuloplasty: To date, Valcare Amend is the only transapical mitral valve (MV) ring to have been implanted in patients. The device allows for stabilization of the annulus through a complete semirigid D-shaped ring. The first-in-human successful procedure was performed in 2016 by our Group and subsequent clinical experience included a total of 14 implanted patients. Currently the technology is under clinical trial evaluation to validate the efficacy and safety profile of the device.
Chordal Repair: Beating heart chordal implantation via trans-apical approach is a current feasible, safe and reproducible option. Neochord DS1000 is the most widely used technology in the field, with a solid procedural experience and good results in well-selected patients. Its clinical use has been validated in Europe since 2012, while it is still under clinical investigation in the United States. Harpoon TDS-5 system is a novel technology, recently CE mark approved for clinical use.
Conclusions: Transapical micro-invasive technologies are current viable therapies to treat MR in selected patients. Embracing transcatheter MVRe therapies should guide the cardiac surgeon through the new revolution of micro-invasive MV tailored repair.

Introduction

Mitral valve regurgitation (MR) affects more than 4 million people in the United States (US) and Europe, with an incidence of 1-2% of the western population. Its prevalence increases with age, affecting up to 10% of the population above 75 years11Nkomo VT, Gardin JM, Skelton TN, et al. Burden of valvular heart diseases: a population-based study. Lancet 2006;368:1005-11. 10.1016/S0140-6736(06)69208-8.
According to current American and European guidelines, surgery is the gold standard therapy to treat MR in symptomatic patients, supporting surgical repair over replacement with extracorporeal circulation whenever possible 22Authors/Task Force Members:, et al. ”2017 ESC/EACTS Guidelines for the management of valvular heart disease.” European journal of cardio-thoracic surgery 52.4 (2017): 616-664.. Despite MR represents the most frequent valvular heart disease requiring surgery in the US and the second most common in Europe33Enriquez-Sarano, Maurice, Vuyisile T. Nkomo, and Hector I. Michelena. ”Mitral regurgitation.” Valvular Heart Disease. Humana Press, 2009. 221-246., up to one third of patients with severe MR are never referred and nearly half are denied for surgery because of prohibitive risk due to age and comorbidities44Vesely MR, Benitez RM, Robinson SW, et al. Surgical and Transcatheter Mitral Valve Repair for Severe Chronic Mitral Regurgitation: A Review of Clinical Indications and Patient Assessment. J Am Heart Assoc 2015;4. doi: .10.1161/JAHA.115.002424. Moreover, by 2030, the increase of the population age will translate in an estimated increase of 50% in heart failure prevalence, resulting in a significantly higher rate of MR, especially due to functional mechanisms55Udelson JE, Stevenson LW. The future of heart failure diagnosis, therapy, and management. Circulation. (2016) 133:2671–86. 10.1161/CIRCULATIONAHA.116.023518. Therefore, new less-invasive therapies are needed to further expand the slice of population to be treated.
Recently a new concept of micro-invasive cardiac surgery has been introduced to identify a revolutionary group of techniques requiring neither cardiopulmonary bypass nor aortic cross-clamping66D’Onofrio A, Gerosa G. Shifting a paradigm of cardiac surgery: from minimally invasive to micro-invasive. J Heart Valve Dis. 2015. 24: 528-30.. This evolution in technologies allows for off-pump, beating heart procedures, with a very small skin incision or even totally percutaneously performed, often requiring limited anesthesiologic support, with the contribution of multimodality imaging77D’Onofrio A, Gerosa G. Technique versus technology and the (r) evolution of cardiac surgery: a professional journey from classical surgery to embracing intervention. European Journal of Cardio-Thoracic Surgery. 2017. 52.5: 835-837.. Transcatheter aortic valve replacement represents the clearest example of such micro-invasive procedures. In the very near future these emerging therapies will likey have a central role, especially in the high-risk patient population, in both degenerative and functional MR treatment, despite only weak recommendations are given for their use by current guidelines (COR IIb, LOE C)2.
Nowadays the interest of the cardiac surgeon community towards new micro-invasive procedures is abruptly expanding with the potential to be adopted as a valuable alternative to conventional surgery, even if, as far as MVRe is concerned, there are still limitations that need to be overcame. Once the MV is reached by the use of transapical or transfemoral puncturing, these technologies can often perform just a single repair technique, acting on a specific component of the mitral apparatus (chordae OR leaflets OR annulus), in contrast to surgical repair, that allows for combined multi-target procedures (chordae AND leaflets AND annulus). Nevertheless, simultaneous implantation of different devices has already been reported in well-selected patients, even if more data are needed to validate the practice88Colli A, Raanani E, Cobiella J, Wrobel K, Nombela L, Maroto L, et al. Transapical and transfemoral combined mitral valve repair with annular and leaflet therapies. The Annals of Thoracic Surgery. 2020..
In the present manuscript, we aim to review currently available technologies intended to treat MR through a micro-invasive transapical approach, including annuloplasty and chordal repair options.