New-generation devices have made transcatheter aortic valve replacements (TAVRs) easier to perform in patients with pure native aortic regurgitation (AR), suggests a study published in the Journal of the American College of Cardiology.
Compared to early-generation devices, the new valves achieved a significantly higher device success rate (81.1 percent versus 61.3 percent) in a nonrandomized study of 331 patients. This result was driven by lower rates in second valve implantation (12.7 vs. 24.4 percent) and post-procedural AR of at least moderate severity (4.2 vs. 18.8 percent).
Post-procedural AR of moderate or worse was associated with a 2.85-fold risk of all-cause mortality at one year, reported lead researcher Sung-Han Yoon, MD, and colleagues.
“Even in patients without sufficient aortic valve calcification or those with a dilated aorta, more accurate positioning and lower rates of post-procedural AR and second valve implantation were achieved with the device enhancements: longer stent frame, new delivery system and sealing skirt in the Sapien 3 (Edwards Lifesciences); recapturability/repositionability, reduced overall height, and redesigned stent frame with optimized radial force in the Evolut R (Medtronic); and new anchoring mechanism with clipping of the native aortic valve cusps in the JenaValve (JenaValve Technology),” the researchers wrote.
TAVR has traditionally been used to treat patients with severe aortic stenosis considered to be at high risk for surgery, with recent studies also demonstrating its feasibility in stenosis patients at intermediate surgical risk. Operators have hesitated to opt for TAVR in patients with pure native AR due to “absent aortic valve calcification and the subsequent difficulty in anchoring the transcatheter valves,” according to Yoon et al.
People with predominant AR are not indicated for TAVR in current clinical guidelines, the authors pointed out, but improving device technology and operator experience has led to an increase in off-label TAVR procedures for these patients and those with other valvular diseases.
“The initial report of TAVR using the early-generation self-expanding prostheses for pure native AR showed high rates of procedural complications,” they wrote. “However, the new-generation devices with retrievability and repositioning capacity, external sealing cuff, or unique anchoring mechanisms could potentially overcome the procedural challenges in treating pure native AR.”
The researchers studied patients from a 40-center, international registry, which included individuals with severe AR and comorbid conditions that would prevent surgical valve replacement. Early generation devices were used in 119 patients while 212 participants received new-generation valves.
Patients receiving the early generation devices were at higher surgical risk, with a mean Society of Transthoracic Surgeons (STS) score of 7.6 compared to an STS score of 6.2 for patients receiving new-generation devices. They were also more likely to have the device implanted via transfemoral access (87 percent versus 60.8 percent of new-generation patients).
There were no significant differences in one-year all-cause mortality between the groups, but the new-generation devices were associated with a lower rate of one-year cardiovascular mortality (9.6 vs. 23.6 percent). Early generation devices were linked to an increased risk of acute kidney injury but a lower risk of stroke.
The authors, many of whom disclosed relationships with the manufacturers of the valves, suggested further studies are needed to determine the optimal selection of patients and device types for TAVR in people with pure native AR.
“Due to lack of randomized studies in pure native AR, the findings in the present study need cautious interpretation,” they wrote. “TAVR in pure native AR should be considered for patients deemed high surgical risk after consultation with the multidisciplinary heart team, and the generalization of this procedure should be recommended only after further investigation. Further device development dedicated for treating pure native AR, establishment of device sizing guideline in this population, and accumulation of procedural experience and scientific knowledge are awaited to provide improved procedural and clinical outcomes in the future.”