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Next-generation self-expanding TAVR valve safe, effective in severe aortic stenosis
New data show that a next-generation self-expanding transcatheter aortic valve with an external pericardial wrap was associated with excellent hemodynamic results as well as improved annular sealing with less paravalvular leak in patients with severe symptomatic aortic stenosis who were at increased surgical risk.
“Since it was first introduced, transcatheter aortic valve replacement has shown the potential to offer a safer and less invasive therapy for the treatment of patients with severe symptomatic aortic stenosis. The initial TAVR studies showed us this potential, but also pointed out potential pitfalls, including increased paravalvular leak,” John K. Forrest, MD, director of interventional cardiology from the Yale University School of Medicine at The Yale Heart and Vascular Center, told Cardiology Today’s Intervention.
According to Forrest, the valve (Evolut PRO, Medtronic), which includes an external porcine pericardial wrap, represents the next generation of transcatheter valves with the potential to address paravalvular leak while maintaining the other benefits of TAVR.
Promising results
In the prospective, controlled, non-randomized Medtronic Evolut PRO Clinical Study, Forrest and colleagues implanted the device in 60 patients at eight investigational sites in the United States. The two primary safety endpoints were the incidence of all-cause mortality at 30 days and the incidence of disabling stroke at 30 days. The proportion of patients with no or trace prosthetic valve regurgitation at 30 days served as the primary efficacy endpoint. Valve Academic Research Consortium-2 criteria were used to assess clinical outcomes.
The valve was successfully implanted in all 60 patients. At 30 days, one patient died (1.7%) and one experienced a disabling nonfatal stroke (1.7%). Also at 30 days, aortic regurgitation data were available for 58 patients. Nearly three-quarters of these patients (72.4%) had no or trace aortic regurgitation, all of which was deemed paravalvular in nature. The remainder of these patients (27.6%) had only mild paravalvular leak, and no patients had leak worse than mild, according to the data.
In terms of other clinical outcomes, 10% of patients experienced a major vascular complication at 30 days and 11.7% experienced a life-threatening or disabling bleed. The majority of patients (86.4%) experienced improvement in NYHA functional class, with no patients experiencing worsening NYHA functional class at 30 days.
Ten percent of patients also received a permanent pacemaker. After exclusion of the nine patients with a pacemaker at baseline, the 30-day Kaplan-Meier rate of new pacemakers was 11.8%.
“There were some concerns based on prior valves that the addition of the pericardial wrap might increase the incidence of new pacemakers. As such, the low rate of pacemaker implant, albeit in a small cohort, was good to see,” Forrest told Cardiology Today’s Intervention. “This low incidence is likely due to a combination of physician experience and implant technique.”
The researchers also noted that the mean atrioventricular gradient was 6.4 mm Hg and the effective orifice area was 2 cm2 at 30 days.
Of the 60 patients included in the study, most were elderly (mean age, 83 years) and frail (81.7%) and had increased surgical risk (mean Society of Thoracic Surgeons Predicted Risk of Mortality = 6.4%). Additionally, 65% were women, and 70% had NYHA functional class III or IV symptoms.
Interpretations
In an accompanying editorial, Stephan Windecker, MD, and Jonas Lanz, MD, MSc, both from the University Hospital Bern in Switzerland, noted that the data are promising and indicate that new technologies may help address paravalvular regurgitation, which they dubbed the “Achilles heel of TAVR.”
“We conclude that with the improvement in patient selection, procedural planning, implantation technique, and more recently the advent of external seals, the rate of relevant [paravalvular regurgitation] has been lowered considerably and in view of the results of the most current devices the prospects to definitely seal the Achilles heel of TAVR are promising,” they wrote.
Windecker and Lanz wrote, however, that more data in larger cohorts of patients are needed before drawing firm conclusions.
Overall, the future looks bright, according to Forrest.
“Over the past 10 years, there have been a large number of iterations to transcatheter valves to make them safer, more deliverable and more effective for patients with severe aortic stenosis. Today, as a result of these technological advances, including those seen in the Evolut PRO valve, TAVR represents a therapy that can be potentially offered to the majority of patients with severe symptomatic aortic stenosis,” he said. – by Melissa Foster
For more information:
John K. Forrest, MD, can be reached at john.k.forrest@yale.edu.
Disclosures: The study was funded by Medtronic. Forrest reports he has received grant support or research contracts and consultant fees, honoraria or speakers bureau fees from Edwards Lifesciences and Medtronic. Please see the study for all other authors’ relevant financial disclosures. Lanz reports no relevant financial disclosures. Windecker reports he has received institutional research grants from Bracco, Boston Scientific, St. Jude Medical and Terumo.