Asymmetrical valve expansion after TAVR a cause for concern
Balloon-expandable transcatheter aortic valve replacement (TAVR) valves that fail to expand symmetrically may be associated with worse hemodynamic data, according to a new analysis published in JACC: Cardiovascular Interventions.[1]
The study’s authors explained that calcified debris is not removed during TAVR. This can sometimes result in stent frame issues that cause the transcatheter heart valve (THV) to expand asymmetrically.
“Asymmetrical foreshortening of balloon-expandable TAVR prostheses can be readily detected on fluoroscopy, immediately after THV deployment, by the presence of unequal stent frame heights and may potentially represent a sentinel for adverse hemodynamic outcome,” wrote first author Annette Maznyczka, MBChB, PhD, with Bern University Hospital and the University of Bern, and colleagues. “However, the implications of asymmetrical foreshortening during the inflation of balloon-expandable TAVR prostheses on THV hemodynamic and clinical outcomes are unknown.”
Maznyczka et al. tracked data from the Bern TAVI registry, focusing on more than 1,200 patients who underwent TAVR from February 2014 to June 2022. All patients received a Sapien 3 or Sapien 3 Ultra THV from Edwards Lifesciences.
The mean patient age was 81.2 years old, mean Society of Thoracic Surgeons Predicted Risk of Mortality score was 4.3% and 34.3% were women.
Fluoroscopy results for each patient were reviewed to determine their TAVR asymmetry index. A TAVR asymmetry index of 0%, for example, would mean the THV heights were equal and the valve expanded exactly as it should. This method has previously been used to measure valve asymmetry in mitral valve-in-valve procedures, the authors explained.
TAVR asymmetry indexes ranged from 0% to 26.5%. The median was 1.4%. THV asymmetry was defined as any patient with a TAVR asymmetry index higher than 5.5%.
Overall, the authors determined that THV asymmetry was seen in 17% of patients. These patients had a younger mean age (80 years old) than patients without THV asymmetry (81.4 years old) and were more likely to present with extensive calcification of the noncoronary cusp, smaller baseline aortic valve areas and higher baseline aortic transvalvular gradients.
In addition, the group found that patients with THV asymmetry were more likely to have received a Sapien 3 Ultra valve than a Sapien 3, and they were more likely to have predilatation performed. THV size did not appear to play any role in the odds of THV asymmetry.
Maznyczka and colleagues noted that a higher TAVR asymmetry index was independently associated with impaired THV hemodynamic performance. These patients were more likely to have a mean residual aortic valve gradient ≥20 mm Hg and/or moderate or greater paravalvular aortic regurgitation. The TAVR asymmetry index can also help anticipate when patients will have an impaired THV hemodynamic performance; using 5.5% as a cutoff, for example, was linked to a sensitivity of 77% and specificity of 86%.
“We found that asymmetrical expansion of the THV was associated with hemodynamic valve performance,” the authors wrote. “Patients with high degrees of prosthetic valve asymmetry had a higher risk for increased residual transvalvular gradients … moreover, our analysis suggests that patients with valve asymmetry have a higher risk for relevant paravalvular aortic regurgitation. Hemodynamic valve performance may be a surrogate marker for long-term clinical outcomes.”
On the other hand, THV asymmetry was not associated with an increased risk of long-term hemodynamic valve deterioration, stroke or all-cause mortality after one year.
Reviewing these findings, the authors wrote that they believe this to be the first study to confirm a relationship between asymmetrical THV expansion and an impaired THV hemodynamic performance.
“These findings may have implications for design of balloon-expandable THVs,” the group concluded. “Operators should aim for THV symmetry, and closer clinical and imaging follow-up might be warranted in patients with asymmetrical stent frame foreshortening after TAVR.”
Click here to read the full study in JACC: Cardiovascular Interventions, an American College of Cardiology journal.
Michael has more than 18 years of experience as a professional writer and editor. He has written at length about cardiology, radiology, artificial intelligence and other key healthcare topics.