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10


Structural heart disease


August 2013


Transcatheter Valve News TAVI after open mitral valve surgery is feasible


A single-centre, observational study, published in Interactive Cardiovascular and Thoracic Surgery, showed that transcatheter aortic valve implantation (TAVI) with a self-expanding valve (CoreValve, Medtronic) was a safe and effective treatment for nine severe aortic stenosis patients who had previously undergone mitral valve surgery


G


iuseppe Bruschi (A De Gasperis Cardiology & Cardiac Surgery


Department, Niguarda Ca’ Granda Hospital, Milan, Italy) and others reported that patients with a history of mitral valve surgery are often excluded from TAVI studies because “concerns exist about possible interference, between the mitral prosthetic housing or bioprosthetic struts and transcatheter valve, that might interfere with optimal valve deployment, increasing the risk of prosthesis shift and misplacement.” They added that because of these concerns, the ongoing PARTNER II and CoreValve US pivotal trial studies have both excluded patients who have previously undergone mitral valve surgery. Bruschi et al reported that, as a consequence of prior mitral valve surgery often being a


contraindication for TAVI, “evidence concerning TAVI outcomes in this group of patients remains sparse and limited to a few case reports”. In their single-centre study, the authors reviewed the outcomes of nine patients with a prior history of mitral valve surgery who had undergone TAVI at their centre between 2008 and 2012 (of 172 TAVI patients overall). Of these patients, four had received a Sorin Allcarbon monodisc mitral valve prosthesis, two had received a Sorin Biocarbon bileaflet mitral valve prosthesis, one received a 25mm On-X bileaflet valve (On-X Life Technologies), one received a Perimount bioprosthesis valve (Edwards Lifesciences), and one patient had received a 26mm Carpentier- Edwards physio ring (Edwards Lifesciences). Additionally, the mean interval between the mitral


valve surgery and the TAVI procedure was 12.5 years and four of the patients had undergone two previous operations on the mitral valve. The third-generation of the CoreValve was used in all patients, with seven patients receiving the valve transfemorally and two receiving the valve via a direct aortic access approach. Bruschi et al noted: “The


CoreValve prosthesis was implanted in all patients with immediate improvement of their haemodynamic status. In all patients, mean aortic gradient immediately dropped below 3mmHg after CoreValve deployment; no CoreValve balloon post dilation was needed.” They added that in all patients, procedure success was achieved, paravalvular aortic regurgitation was absent or mild, and that mitral prosthetic function remained unaffected.


However, one patient did require implantation of a new pacemaker because of complete heart block. At a mean follow-up of 18±14 months, echocardiographic evaluation did not reveal any evidence of structural valve deterioration or displacement. One death was reported at two years after TAVI implantation, but this was non-valve related. Commenting on their results, the authors wrote: “In this population, self-expanding valve implantation may guarantee more stability during deployment and probably a direct aortic access with short distance between the entry site and aortic annulus and that better valve deployment control should be advantageous in these patients.” However, they stated that the small sample size in their study “prevents reaching any


definite conclusions.” They added: “Prospective studies involving larger numbers of patients and long-term follow- up are required to confirm these beneficial findings.” Bruschi told Cardiovascular


News: “We have treated, to date, 10 patients, who previously underwent mitral valve surgery, with CoreValve and we have had excellent results with no interference with the mitral prosthesis. We believe that the key point is not only patient’s selection, including multislice CT evaluation of the distance between the aortic annulus and the mitral prosthesis, but accuracy and control of valve deployment is also crucial. For this reason, we believe that in case of a short distance, an alternative access, such as the direct aortic approach, may be of use.”


Poor economy may be cause of underuse of TAVI in Europe


A study published ahead of print in the Journal of the American College of Cardiology suggests that the use of transcatheter aortic valve implantation (TAVI) devices varies greatly across Europe and that, overall, the therapy is underused. Furthermore, the study indicates that this underuse is closely associated with national economic indices and reimbursement strategies


D


arren Mylotte, Department of Interventional Cardiology, McGill University Health


Center, Montreal, Canada, and others wrote that while anecdotal evidence suggests that TAVI use varies great across Europe, TAVI use in Europe (and factors influencing its use) have not been formally described. They added such information could have “implications for healthcare resource allocation, service deployment planning, assessing equitable patient access, and physician training”. Therefore, Mylotte et al aimed to “address this information gap” by examining trends in TAVI implantation rates and centres across 11 European countries since the intervention was CE marked in 2007. They stated: “In addition, we investigated the factors that may influence the heterogeneous adoption of this novel technology across nations.”


Using data from national registries and databases from the 11 countries (Germany, France, Italy, UK and Northern Ireland, Spain, The Netherlands, Switzerland, Belgium, Portugal, Denmark, and Ireland), the authors identified 158,371 potential TAVI candidates (patients with severe aortic stenosis, who are either inoperable or at high surgical risk). However of these


they reported that the number of TAVI implants per million was significantly associated with healthcare spending as a percentage of GDP (p=0.025) and was significantly associated with healthcare spending per capita (p=0.005). They added that although not significant, a trend for increased TAVI use among countries in which healthcare was principally funded by social insurance (eg. Germany) compared with countries in which healthcare was principally funded by taxation (eg. UK) was also observed.


Nicolo Piazza


candidates, there were only 28,400 TAVI recipients. Mylotte et al commented: “Thus, the calculated weight average TAVI penetration rate in 2011 was 17.9%.” They added that Germany had the highest penetration rate (36.2%) while Portugal had the lowest penetration rate (3.4%).


According to the authors, gross domestic product (GDP) per capita— thought to be a reliable indicator of a country’s standard of living—was not associated with TAVI use. However,


Furthermore, Mylotte et al commented: “TAVI-specific reimbursement systems were associated with a 3.3-fold higher number of TAVI implants per million (≥75 years) than constrained systems (p=0.002).” To validate their findings, the authors used data from BIBA MedTech datasets for TAVI implant numbers. They said: “There was satisfactory agreement between the two sources of information and both provided similar results and conclusions.”


Summarising their results, Mylotte


et al commented: “Not surprisingly, the lowest TAVI implantation rates were found in Spain, Portugal, and Ireland who are currently experiencing substantial economic hardship. In


these nations, the medical device industry could provide additional support to develop and maintain TAVI programmes.”


They added that adoption of new technology, such as TAVI, was a “slow process” as it required hard clinical evidence, physician training, and clinical and financial planning. However, the authors said that as TAVI was associated with therapeutic benefit in inoperable patients, its known cost-effectiveness, and its less invasive nature, “the protracted uptake of TAVI technology may have negative consequences for patients, physicians, and administrators. Although TAVI penetration is not necessarily a surrogate for quality of medical care, it may suggest the need for enhanced patient access to novel and potentially life-saving therapies.” Study author Nicolo Piazza, Department of Cardiovascular, German Heart Center, Munich, Germany, told Cardiovascular News: “The results of this study may provide benchmark performance measures (eg. average number of TAVI procedures a centre should be performing) and also may also provide regulatory and government bodies information to better structure TAVI resource use (eg. too many or too little centres within a country or region).”


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