Percutaneous valve implantation via the transapical approach into failed mitral biological prostheses—so-called valve-in-valve therapy—is feasible and offers “favorable” outcomes through mid-term follow-up, according to a paper published online February 26, 2013, ahead of print in the Journal of the American College of Cardiology.
Anson Cheung, MD, and colleagues at St. Paul’s Hospital (Vancouver, Canada) treated 23 patients with severe mitral bioprosthetic valve dysfunction (median of 10 years postreplacement) between July 2007 and September 2012. All were deemed ineligible for conventional repeat mitral valve replacement surgery by a team of cardiologists and cardiac surgeons.
No Intraoperative Complications, High Midterm Survival
Transcatheter valve-in-valve procedures, performed via the transapical route, were successful in all patients using Edwards Lifesciences (Irvine, CA) balloon-expandable devices including Cribier-Edwards (n = 1), Sapien (n = 12), and Sapien XT (n = 10). Most patients received 26-mm valves (n = 13), with the rest evenly split between 23-mm and 29-mm sizes (n = 5 for each).
\No intraoperative complications such as valve malposition or embolization were observed, and there was no need for mechanical circulatory support. After treatment, mitral transvalvular gradient decreased from 11.1 ± 4.6 mm Hg to 6.9 ± 2.2 mm Hg (P < 0.01), and intervalvular regurgitation was absent (47.8%) or mild (52.2%). There were no cases of transvalvular regurgitation.
No deaths occurred either in-hospital or by 30-day follow-up.
At a median follow-up of 2 years (interquartile range, 376-1,119 days), the survival rate was 90.4%. One patient with migration of the transcatheter valve underwent successful valve-in-valve reintervention at 2 months. Patients had good valve performance at final follow-up, and all but 1 (95.6%) were classified as New York Heart Association class I/II.
During hospitalization (median length of stay 6 days), 1 major stroke (4.4%) and 6 major bleeds (26.1%) occurred. Two patients (8.7%) developed stage III acute kidney injury, of which 1 needed temporary renal replacement therapy. One patient who had preexisting atrioventricular conduction disturbance required a permanent pacemaker at 3 days after the procedure.
Most patients (n = 15; 65.2%), all of whom had A-fib at baseline, were discharged on either aspirin 81 mg or clopidogrel 75 mg daily for 6 months plus anticoagulation, while 7 were discharged on 6 months of dual antiplatelet therapy. One patient with A-fib and at high risk for bleeding received warfarin alone.
Growing Interest in Valve-in-Valve
Ted E. Feldman, MD, of Evanston Hospital (Evanston, IL), told TCTMD in a telephone interview that the patient population treated here cannot be helped by medical therapy. “Their prognosis without valve-in-valve is dismal. We would expect at least 30% to 50% of them to not make it a year,” he said, citing older age and high surgical risk. “So the late outcome reported in this paper is really very positive and remarkable.”
Valve-in-valve therapy has, in general, been recognized as a “very attractive therapy [for high-risk patients with failed bioprostheses] for quite a while, and the use of valve-in-valve has grown very rapidly,” Dr. Feldman noted. As an investigational therapy, however, its use is limited in the United States.
According to Dr. Feldman, there have been “2 avenues” for US operators seeking to gain experience with this procedure. The first—the PARTNER 2 Valve-in-Valve registry using Edwards valves—recently closed after enrolling the planned 100 patients, a cutoff set by the US Food and Drug Administration, he reported. “The [second] thing that’s been going on in the United States [for a couple of years] is some operators have been using the Melody pulmonic valve [Medtronic, Minneapolis, MN] for valve-in-valve.”
Working Out the Best Approach
Dr. Feldman said that an interesting aspect of the current paper is its exclusive use of the transapical approach.
Dr. Cheung and colleagues “had tried some transseptal delivery for valve-in-valve to the mitral position very early and found that, in their practice, apical is a much more direct and secure route to accomplish this,” he said, adding that some European centers have found success with the antregrade transseptal approach. “It’s clear that [transseptal] is more challenging than apical for the operator. But it’s also clear that it can be done both ways.”
Thus far, valve-in-valve has been more commonly employed in failed aortic bioprostheses, Dr. Feldman said, likely because “we know so well how to do TAVR in the aortic position.” He proposed that mitral valve-in-valve procedures “may be more amenable to a greater number of practices through an apical approach.”
Transapical Approach ‘Quite Easy’ for TAVR Operators
When using the transapical approach, Dr. Cheung said, the mitral procedure is “not that difficult. It’s quite easy [for operators accustomed to standard TAVR] to adapt to doing that.” The transcatheter method is notable for its “simplicity” and involves “an inch or inch-and-a-half incision to the left chest, without cardiopulmonary bypass, and usually lasts less than an hour,” a stark contrast to repeat surgery, he added.
However, mitral bioprostheses are larger than those for the aortic valve at 27 mm to 29 mm compared with 21 mm to 23 mm, Dr. Cheung noted. “So the type of [device] you have to put into the old mitral prosthesis is much bigger.”
As to the question of durability, Dr. Feldman pointed out that patients who already have failed bioprostheses may represent a group “prone to valve degeneration, and I think the expectation about valve durability in the valve-in-valve group—both mitral and aortic—has to be tempered by that possibility. It will be different than the de novo TAVR patients.”
Dr. Cheung said that in the event of a second valve failure, a repeat mitral valve-in-valve procedure is possible. The large size of the mitral valve leaves room for multiple devices to be implanted successively if required, he explained.
Patients were elderly (aged 81 ± 6 years) and had high Society of Thoracic Surgeons scores (12.2 ± 6.9%). The primary mechanism of mitral biosprosthetic failure was stenosis in 30.4% of patients, regurgitation in 39.1%, and mixed in 30.4%. None had significant perivalvular regurgitation.