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TAVR with repositionable valve safe, effective at 1 year
One-year data from the RESPOND study confirm the safety and efficacy of a repositionable bioprosthetic aortic valve for transcatheter aortic valve replacement, according to a study published in JACC: Cardiovascular Interventions.
“The Boston Scientific Lotus Transcatheter Heart Valve has a unique design that held great promise in smaller studies. The aim of the RESPOND trial was to see how the Lotus would perform in every day clinical practice,” Nicolas M. Van Mieghem, MD, PhD, FESC, FACC, director of interventional cardiology, Thoraxcenter, Erasmus University Medical Center Rotterdam, wrote in an email to Cardiology Today’s Intervention.
Among 996 patients implanted with a repositionable valve, 1-year follow-up was available for 99.9% of patients. At 1 year, cumulative all-cause mortality was 11.7%, with the likelihood of death at 1 year being lower among patients with higher left ventricular ejection fraction at baseline. Conversely, a history of chronic obstructive pulmonary disease, dialysis-dependent renal failure or atrial fibrillation was associated with a greater likelihood of mortality.
Also, at 1 year, the rate of disabling stroke was 4.1%, and the rates of permanent pacemaker implantation were 32.3% among all patients and 37.2% among patients who did not have a pacemaker at baseline.
The prospective, open-label, postmarket RESPOND study enrolled 1,014 patients from 2014 to 2016 at 41 centers in Europe, New Zealand and Latin America. Of the 996 patients included in the as-treated population, the mean age was 80.8 years, 50.8% were women and the mean Society of Thoracic Surgeons score was 6%.
Additional improvements
Transthoracic echocardiography assessment was available for core lab evaluation in 62.6% of patients at 1 year. Results showed that improvement in valve hemodynamics after TAVR was sustained at 1 year. Additionally, aortic valve area improved from baseline to 1 year (P < .001) and mean aortic valve gradient decreased from baseline to hospital discharge (P < .001) and remained lower at 1 year.
The majority of patients (94.5%) had no or trace paravalvular leak at 1 year, whereas no patients had severe paravalvular leak, 0.4% had moderate paravalvular leak and 5.1% had mild paravalvular leak.
The researchers also noted improvements in NYHA functional class at 30 days that were maintained at 1 year. When compared with baseline, nearly 90% of surviving patients were classified as NYHA functional class I or II, with 79% of patients improving one class and 31% improving two classes (P < .001 for both) at 1 year.
Improvements in health-related quality of life, as measured by the self-rated EuroQoL 5EQ-5D questionnaire, and overall quality of life, as assessed by self-reported score on the Visual Analog Scale, were noted at 1 year.
“One-year outcomes from the RESPOND study confirm the sustained safety and efficacy of TAVR with the Lotus valve in a large population treated in routine clinical practice,” the researchers wrote.
RESPOND Extension study
In the RESPOND Extension cohort, 50 patients were treated with the Lotus valve with Depth Guard technology that included a modified delivery system. The patients’ baseline characteristics were mostly comparable to those of the main study, with the exception of a higher baseline STS score in the Extension cohort.
At 30 days, there were no deaths, 6% of patients experienced a stroke and 2% experienced a disabling stroke. Permanent pacemakers were implanted at 30 days in 18% of all patients and in 20% of patients who did not have a pacemaker at baseline. Aortic valve area also improved from baseline to 30 days and mean aortic valve gradient declined from baseline to hospital discharge.
Again, most patients had no or trace paravalvular leak (86.5%) and no patients had moderate or severe paravalvular leak. More than 95% of surviving patients were NYHA functional class I or II, 72.3% improved by one class and 27.7% improved by two classes at 30 days (P < .001 for both).
“The results were completely in line with my expectations. The device has a stunningly low paravalvular leak rate that is the result of the sealing skirt and the fact that the device is totally repositionable and retrievable even upon complete deployment. … With Lotus the operator can assess the presence of paravalvular leakage and reposition if deemed too much. As such the paravalvular leak frequency is similar to what surgeons obtain in the operating room,” Van Mieghem told Cardiology Today’s Intervention.
“The downside of the technology at that point was the higher need for permanent pacemakers. We saw a wide distribution in the pacemaker rate among participating centers. Some centers had significantly lower rates than others, which suggests that there are ways to limit this pacemaker need by adjusting technique and proper planning."
Van Mieghem also noted that the modified Lotus valve warrants further study.
“Now the question is: does it maintain the very low paravalvular leakage with a lower need for pacemakers?” he said.
Remaining questions
In contemporary TAVR practice that focuses on elderly patients, Van Mieghem said that the Lotus platform is an interesting and unique transcatheter valve that has demonstrated excellent clinical outcome in the RESPOND trial and may also be preferable in specific anatomies, such as heavily calcified aortic roots at risk for aortic rupture or in the case of severe aortic regurgitation.
However, the RESPOND study was not without limitations, including the fact that it was not a randomized study. Further, only 62.6% had echocardiographic follow-up at 1 year, Van Mieghem and colleagues noted.
Also, in an accompanying editorial, John G. Webb, MD, and Janarthanan Sathananthan, MBCHB, PhD, both from the Centre for Heart Valve Innovation, St. Paul’s Hospital, University of British Columbia in Canada, highlighted the attractive features of the repositionable valve as well as some concerns.
“The Lotus valve has some unique features that are desirable. The appeal of being able to reposition or retrieve a poorly positioned or sized valve is undeniable. Also unique is the relative absence of significant paravalvular leaks,” they wrote. “However, improvements in patient screening, pre-procedural sizing and the ability to accurately position other contemporary [transcatheter heart valves] have lessened these differences, at least in the great majority of patients.”
Additionally, the high rate of atrioventricular conduction block associated with the Lotus valve is concerning.
“A newer Lotus delivery catheter intended to result in less traumatic and higher [transcatheter heart valve] implantation, achieved a lower 20% 30-day pacemaker rate in a small cohort of 50 patients in the RESPOND Extension cohort, which is promising,” Webb and Sathananthan wrote. “Hopefully, the Depth Guard delivery catheter in combination with the next-generation Lotus Edge valve may narrow the gap in terms of atrioventricular block and the important implications associated with this.” – by Melissa Foster
For more information:
Nicolas M. Van Mieghem, MD, PhD, FESC, FACC, can be reached at n.vanmieghem@erasmusmc.nl.
Disclosures: The RESPOND study was sponsored and funded by Boston Scientific. Van Mieghem reports he has received grants from Abbott Vascular, Boston Scientific, Claret Medical (a subsidiary of Boston Scientific), Edwards Lifesciences, Medtronic and PulseCath, and advisory fees from Boston Scientific. Please see the study for all other authors’ relevant financial disclosures. Webb reports he is a consultant to and has received research funding from Edwards Lifesciences, Abbott Vascular, Boston Scientific and ViVitro Labs. Sathananthan reports no relevant financial disclosures.