If They Survive First Month, Mitral Annular Calcification Patients Treated With Transcatheter Valves Do Well at 1 Year
The MAC Global Registry has faced some setbacks, but trial and error has paid off in these patients who otherwise have limited options.
PARIS, France—Results from the Mitral Annular Calcification (MAC) Global Registry suggest that if patients can survive the complex initial procedure and its aftermath, they have a good chance of surviving with sustained improvement of symptoms out to 1 year.
As previously reported by TCTMD, the MAC registry is a multinational collaboration collating outcomes and sharing tips and techniques among investigators using balloon-expandable, transcatheter devices designed for aortic valve replacement in patients with severe mitral annular calcification who are not candidates for surgery or other types of repair. The procedure has faced its share of hurdles and setbacks, but 30-day results from the registry demonstrated that with improved awareness of procedural risks—particularly left ventricular outflow tract (LVOT) obstruction—survival had been on the rise.
Now, presenting 1-year results for patients who survived beyond 30 days, Mayra Guerrero, MD (NorthShore University Health System, IL), lead author of the study, spoke at EuroPCR 2017 with optimism and pride about the declining hazards and growing achievements seen with the procedure.
“Patients who survive the 30-day procedure period have sustained improvement of symptoms at 1 year,” she said. “The reintervention rate after 30 days is low, valve performance is maintained at 1 year, and most deaths after 30 days are noncardiac.”
Learning and Applying
The 1-year results include outcomes among the 77 patients from the original cohort who survived beyond the first 30 days. In that first month, as reported previously, operators faced high rates of acute catastrophic failures and fatal complications: 29 out of 116 patients died. Of the 87 who survived the first month, 29 died before the 1-year mark and 10 had not quite reached 12 months, leaving a total of 48 patients alive at 1 year who were available for detailed analysis.
Of note, more than half of the deaths at 1 year were noncardiac, leaving Guerrero to remind the audience of the importance of avoiding so-called “Cohort C” patients—those too elderly or too sick with other comorbidities to benefit from treatment. As for the cardiac deaths, the most common causes were LVOT obstruction (in seven patients), heart failure, and endocarditis. Of note, two patients died of valve thrombosis—both of these patients were on warfarin at the time, but they had suboptimal international normalized ratios, Guerrero said.
Among survivors, adverse events were uncommon, as was valve reintervention, which was necessary in a total of 13 cases, just four of which occurred after the initial 30-day period.
Asked by panelist Samer Mansour, MD (University of Montreal, Canada), about what prompted the need for a second valve, Guerrero said that 40% of cases were due to valve migration and 60% to paravalvular leak. “The learning curve was very difficult at the beginning,” she admitted. “To be honest, we didn’t know anything.” For one, operators lacked any knowledge of the best landing zone for the device, and many patients were treated with the first-generation valve. “Over time the need for a second valve has decreased because we are working with a better technology, the Sapien 3, and also we have learned a lot more about sizing and positioning. The important thing is, this need for a second valve was not a predictor of mortality or adverse events.”
Thirteen patients (11.2%) experienced LVOT obstruction, which was lethal in all but two patients despite a range of treatment attempts including valvuloplasty, surgery, and alcohol septal ablation. The latter technique was used in six patients and was the only intervention to be successful. Indeed, Guerrero and colleagues have pioneered a new approach, preventively screening for patients whose anatomy predisposes them to LVOT obstruction and, rather than using alcohol septal ablation as a bailout strategy, have started pretreating them with alcohol ablation 6 to 8 weeks prior to their valve procedure. They then verify on CT that the new size of neo-LVOT, postablation, is adequate. If not, they may consider transatrial transcatheter mitral valve replacement after surgical resection of the anterior leaflet, or enrollment in the LAMPOON trial.
“We have not had to do a rescue for LVOT obstruction in more than 1 year, and the reason is that we now do preemptive alcohol septal ablation,” she said.
For the 34 (out of 48) survivors who had undergone echocardiographic follow-up, mean mitral valve gradients remained similar to those seen at 30 days, and NYHA class improvements seen from baseline at 30 days were also relatively stable at 1 year, with most patients improving by at least two categories.
Asked whether she believes transcatheter valve replacement is the way forward for patients with this specific type of mitral valve disease, Guerrero said, “I think for this patient population, yes. Whether it is going to be this valve design [the Sapien 3] or a different one, that we’ll have to see.”
Tendyne, she noted, has designed a valve specifically for the mitral valve and it is in the process of early evaluation. “So the field is no longer dominated by the balloon-expandable valve.”
Congratulating Guerrero for what she and colleagues have achieved through the MAC registry, session co-chair Eric Eeckhout, MD (Centre Hospitalier Vaudois - Lausanne, Switzerland), observed, “It seems as though, if these patients survive the burden of the first 30 days and they are not too sick from other diseases, they can have a good outcome.”
Guerrero agreed, noting that she is leading the multicenter, investigator-initiated Mitral Implantation of Transcatheter Valves (MITRAL) trial, which has now passed the halfway mark for enrollment. “Hopefully,” she said, addressing the panel, “you can invite me next year to show you the results.”
Guerrero M. One-year outcomes of TMVR with balloon expandable aortic transcatheter heart valves in patients with severe mitral annular calcification: update from the Global registry. Presented at: EuroPCR 2017. May 16, 2017. Paris, France.