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.
Giuseppe Bruschi (A De Gasperis Cardiology and 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 Technologie), 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.”