June 9, 2026Journal of the American College of Cardiology
Bioprosthetic Aortic Valve Leaflet Thickening in the Evolut Low Risk Sub-Study
Key result
TAVR yields similar HALT rates to surgery with no correlation to valve hemodynamics.
- n=318
Why the study?
Subclinical leaflet thrombosis has been reported after bioprosthetic aortic valve replacement, but the incidence and clinical implications of hypoattenuated leaflet thickening and reduced leaflet motion remain unclear.
Does TAVR compared to surgical aortic valve replacement affect the frequency of hypoattenuated leaflet thickening (HALT) and reduced leaflet motion (RLM) in low-risk patients not on oral anticoagulation?
Population
Patients not on oral anticoagulation enrolled in the Evolut Low Risk randomized trial
Comparison
TAVR vs surgery
Design
Prospective randomized trial sub-study
Follow-up
1 year
Authors
Discussion
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Member takes
Key expert perspectives
Captured external expert commentary on this paper, strongest first. Original sources are linked where available.
“no one knows how much subclinical valve thrombosis truly matters. Even in low-risk patients, these cases come and go. The rate is definitely higher than what we probably should be seeing—it's over 20%—[but] some disappear, and some appear. So we just don't know what kind of conditions, whether it's patient, anatomic, device-related, or procedure factors, we can pinpoint to better prevent this from happening.”
“That shows that HALT is a dynamic process. It's still poorly understood.”
“it's one of more thoughtful reviews I've seen on the subject”
Implication
Comparable HALT/RLM rates after TAVR or SAVR in low-risk patients leave hemodynamics unaffected; confirms high prevalence of subclinical leaflet thrombosis.
Key Points
- The study aims to investigate leaflet thickening in bioprosthetic aortic valves in low-risk patients.
- Randomized trial
- Evaluated bioprosthetic valve performance and leaflet dimensions
- Sample included low-risk patients undergoing valve replacement
- Leaflet thickening was observed in a significant percentage of patients post-implantation.
- The average event rate of thickening was X%, indicating a marked change over time.
Study Design
Type
RCT (n=318)
Randomization
Randomized
Structured PICO
Does TAVR compared to surgical aortic valve replacement affect the frequency of hypoattenuated leaflet thickening (HALT) and reduced leaflet motion (RLM) in low-risk patients not on oral anticoagulation?
P
Population
318 patients at low risk for surgery not on oral anticoagulation who underwent TAVR or surgical aortic valve replacement, followed for 1 year.
I
Intervention
Transcatheter aortic valve replacement (TAVR) with supraannular, self-expanding bioprostheses
C
Comparator
Surgical aortic valve replacement
O
Outcome
Frequency of hypoattenuated leaflet thickening (HALT) at 30 days and 1 year, analyzed by an independent core laboratory using standardized definitionssurrogate
Main Result
Absolute Event Rate: 17.3% vs 16.5%
Subclinical leaflet thrombosis (HALT and RLM) is frequent but dynamic in the first year after both TAVR and surgical aortic valve replacement in low-risk patients, without affecting valve hemodynamics.
Cite This Study
Blanke et al. (2020) conducted an RCT in Aortic valve replacement in patients at low surgical risk (n=318). Self-expanding transcatheter aortic valve replacement (TAVR) vs. Surgical aortic valve replacement was evaluated on Frequency of hypoattenuated leaflet thickening (HALT) at 30 days and 1 year. The frequency of hypoattenuated leaflet thickening was similar after TAVR and surgery at 30 days (17.3% vs 16.5%) and 1 year (30.9% vs 28.4%), and did not correlate with valve hemodynamics.