NEWS & VIEWS DECADE IN REVIEW—VALVULAR DISEASE

Current perspectives on treatment of valvular heart disease Friedrich W. Mohr

Tremendous advances in the understanding and treatment of structural heart valve disease have been made in the past decade, including widespread utilization of minimally-invasive surgical procedures and the invention and evolution of numerous interventional techniques. These innovations will become the norm in therapy for valvular disease in the future. Mohr, F. W. Nat. Rev. Cardiol. advance online publication 23 September 2014; doi:10.1038/nrcardio.2014.138

Valve repair and replacement continue to be better treatment options than conservative management for patients with structural heart valve disease. The past decade has seen major advances in the approaches used to perform these procedures, especially with the advent of minimally-­invasive surgical and interventional techniques. Some of these techniques are still in their infancy, whereas others are being routinely used globally, particularly in high-volume centres. These developments have enabled heart specialists to treat an increasingly wide spectrum of patients, especially those who would otherwise have been considered inoperable. Simultaneous progress in imaging has improved delineation of the anatomy and pathology of heart valves. One of the most remarkable accomplishments has been the establishment of the Heart Team concept, which involves experi­ enced cardiologists and cardiac surgeons collaborating to devise unbiased treatment s­trategies for patients. In the surgical treatment of aortic valve disease, two new trends have been observed in the past 10 years. Firstly, a major shift worldwide has occurred towards increased use of biological valve prostheses, which has been boosted by the availability of newergeneration bioprostheses with excellent haemodynamic characteristics and longterm durability (Figure  1). 1 Secondly, minimally-invasive procedures through small incisions have been shown to have the same safety and efficacy as those performed conventionally through a standard median sternotomy. The development of

sutureless implants has further facilitated these approaches. One of the most memorable developments was the first transcatheter aortic valve implantation (TAVI) in 2002 by Alain Cribier,2 and its establishment as an effective treatment in old, morbid, and virtually inoperable patients. The benefits of avoiding a sternotomy, extracorporeal circulation, cardioplegic arrest, and (with a trans­femoral approach) even general anaesthesia, have given this technique a boost, despite higher rates of residual aortic regurgitation, pacemaker implantations, and early technical challenges after the launch of these prostheses. Meanwhile, with the availability of a multitude of improvised valve prostheses and hardware used for implant­ation, as well as the growing experience of cardiac surgeons and interventional cardio­logists, TAVI has become a routine pro­cedure and a good alternative for inoperable and high‑risk patients (Figure 1). Similarly in mitral valve surger y, attempts to minimize patient trauma have led to interesting progress in minimallyinvasive surgery. Both mitral valve replacement and reconstruction can be performed safely using minimally-invasive or even robot-assisted techniques in centres with sufficient experience. Repair for mitral regurgitation has become an indicator of quality in many centres. We have learned that reconstruction is feasible and desirable in most patients with degenerative disease. However, the results of reconstruction for ischaemic mitral regurgitation are mixed, particularly in the long term.3 As a result

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of the poor prognosis in these patients owing to the combination of progressive heart failure and mitral regurgitation, the idea of interventional treatment seems rational. Several devices that imitate particular steps of the surgical repair technique have been developed. The most widely used device, the MitraClip® (Evalve, USA), mimics the edge-to-edge leaflet repair (Alfieri’s stitch). The device has been shown to relieve symptoms,4 but the longterm results of this technique have yet to be evaluated. The next logical step is true catheter-based mitral valve replacement, and first-in-human experience has already been reported. Even though the anatomical challenges of mitral valve replacement are much more difficult to overcome than those with aortic valve implantation, the sheer number of high-risk patients with mitral valve disease seems to justify the effort of perfecting these devices. The tricuspid valve, which has long been neglected, has received due attention during the past decade. For many years, minimal or mild tricuspid valve incompetence was widely accepted to resolve, or at least not worsen, after treatment of other valves. How­ever, several studies published in the past 10 years have revealed improved long-term outcomes after concomitant tri­ cuspid valve repair, which has resulted in a rising trend for tricuspid valve reconstruction for enlarged tricuspid annuli, even if re­gurgitation is only minimal.5 Another development that has influenced decision-making in valve surgery is the concept of implanting a transcatheter valve inside a previously implanted degenerated bioprosthesis or ring after valve repair.6 These valve-in-valve or valve-inring procedures have not only helped to prevent high-risk patients from having to undergo complex reoperations, but have also resulted in an increased use of bio­ prostheses during the primary operation, often in younger patients—a trend that will only rise in the future. The valve-in-valve concept has also been applied to the pulmonary valve with the availability of the Melody®Transcatheter Pulmonary Valve (Medtronic, USA), which was the first transcatheter valve available on the market. This technology has been a ADVANCE ONLINE PUBLICATION  |  1

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NEWS & VIEWS blessing for children and young adults, who would otherwise have to undergo multiple pulmonary valve reoperations.7 During the past decade, continued efforts have been made to minimize surgical trauma without compromising clinical outcomes, and to make minimally-invasi­ve valve surgery a routine and low-risk oper­ ation. Simultaneously, the development of catheter-based valve implantation has complemented the therapeutic arsenal, thereby expanding the indications to patients who were formerly deemed inoperable. The rapid development of TAVI systems 20,000

and, more importantly, the strong push to spread this technology by the medical industry, interventional cardiologists, and some surgeons has triggered competition between TAVI and conventional surgical valve replacement. With only two randomized studies to compare TAVI and conventional surgery in high-risk patients having been published to date,8,9 further research and trials need to be conducted in the near future, to determine the most suitable therapy for each patient. Unfortunately, TAVI is already being offered to in­termediate-risk and low-risk patients

Herzzentrum Leipzig GmbH–Universitaetsklinik, Struempellstrasse 39, 04289 Leipzig, Germany. [email protected]

TAVI AVR allograft AVR biological AVR mechanical

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Competing interests The author declares no competing interests. 1.

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in the absence of scientific evidence. Care needs to be exercised in advising patients to undergo these procedures, at least until long-term outcomes are known. Therefore, the importance of large, independent studies and surveys, such as the German Aortic Valve Registry (GARY),10 which will provide 5‑year follow-up data on all aortic valve interventions performed in Germany, cannot be overemphasized. Nonetheless, the fast progress in valve repair and replacement technologies over the past decade is extremely encouraging, and raises hopes for further advances in the future.

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Figure 1 | Development of isolated AVR in Germany from 1994 to 2013. The graph shows the rise in the total number of AVRs over this period, the increasing use of biological valves, and the rapid growth in TAVI since 2008. Abbreviations: AVR, aortic valve replacement; TAVI, transcatheter aortic valve implantation.

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Bavaria, J. E. et al. The St Jude Medical Trifecta aortic pericardial valve: results from a global, multicenter, prospective clinical study. J. Thorac. Cardiovasc. Surg. 147, 590–597 (2014). 2. Cribier, A. et al. Percutaneous transcatheter implantation of an aortic valve prosthesis for calcific aortic stenosis: first human case description. Circulation 106, 3006–3008 (2002). 3. Acker, M. A. et al. Mitral-valve repair versus replacement for severe ischemic mitral regurgitation. N. Engl. J. Med. 370, 23–32 (2014). 4. Glower, D. D. et al. Percutaneous mitral valve repair for mitral regurgitation in high-risk patients: results of the EVEREST II study. J. Am. Coll. Cardiol. 64, 172–181 (2014). 5. Navia, J. L. et al. Moderate tricuspid regurgitation with left-sided degenerative heart valve disease: to repair or not to repair? Ann. Thorac. Surg. 93, 59–67 (2012). 6. Dvir, D. et al. Transcatheter aortic valve implantation in failed bioprosthetic surgical valves. JAMA 312, 162–170 (2014). 7. Momenah, T. S. et al. Extended application of percutaneous pulmonary valve implantation. J. Am. Coll. Cardiol. 53, 1859–1863 (2009). 8. Smith, C. R. et al. Transcatheter versus surgical aortic-valve replacement in high-risk patients. N. Engl. J. Med. 364, 2187–2198 (2011). 9. Adams, D. H. et al. Transcatheter aortic-valve replacement with a self-expanding prosthesis. N. Engl. J. Med. 370, 1790–1798 (2014). 10. Mohr, F. W. et al. The German Aortic Valve Registry: 1‑year results from 13 680 patients with aortic valve disease. Eur. J. Cardiothorac. Surg. http://dx.doi.org/10.1093/ejcts/ezu290.

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Decade in review--valvular disease: Current perspectives on treatment of valvular heart disease.

Tremendous advances in the understanding and treatment of structural heart valve disease have been made in the past decade, including widespread utili...
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