TAVR Outcomes for Bicuspid vs. Tricuspid Aortic Stenosis in Low-Risk Patients

Quick Takes

  • Low surgical risk patients (STS-PROM <3%) undergoing TAVR for bicuspid vs. tricuspid aortic stenosis (AS) had similar rates of death and stroke at 30 days and 1 year.
  • Risk of moderate or greater paravalvular regurgitation was not significantly different in bicuspid and tricuspid AS patients.

Study Questions:

How do outcomes of transcatheter aortic valve replacement (TAVR) differ between patients with bicuspid and tricuspid aortic stenosis (AS) who are at low surgical risk?

Methods:

This cohort study, based on the TVT (Transcatheter Valve Therapies) registry, included patients who underwent TAVR with balloon-expandable valves at 684 US centers from 2015–2020. The primary population included patients at low surgical risk, defined as Society of Thoracic Surgeons predicted risk of 30-day mortality (STS-PROM) <3%. Outcomes of TAVR for bicuspid and tricuspid AS were compared. The primary outcomes were death and stroke at 30 days and 1 year. Secondary outcomes included procedural complications and post-procedural echocardiographic findings. To account for baseline differences between patients with bicuspid and tricuspid AS, propensity score-based matching was used.

Results:

A total of 37,660 patients with AS (3,243 bicuspid and 34,417 tricuspid) and low surgical risk were included in the primary analysis. The proportion of patients with bicuspid AS undergoing TAVR increased from 2.8% in 2015 to 6.8% in 2020. Bicuspid AS patients comprised 8.6% of the low-risk population. Among patients aged <65 years, 20.7% had bicuspid AS.

In the propensity score-matched low-risk population (3,168 pairs), the risk of death was similar in bicuspid and tricuspid patients (30-day death: 0.9% vs. 0.8%, hazard ratio [HR] 1.18, 95% confidence interval [CI] 0.68-2.03; 1-year death: 4.6% vs. 6.6%, HR 0.75, 95% CI 0.55-1.02). Risk of stroke was also similar in bicuspid and tricuspid patients (at 30 days: 1.4% vs. 1.2%, HR 1.14, 95% CI 0.73-1.78; at 1 year: 2.0% vs. 2.1%, HR 1.03, 95% CI 0.69-1.53). Serious procedural complications were similar in bicuspid and tricuspid patients, including conversion to surgery, which occurred in 0.4% of each group. Mean TAVR gradients did not differ significantly between bicuspid and tricuspid patients. At 30 days, moderate or severe paravalvular regurgitation was present in 1.8% of bicuspid and 1.1% of tricuspid patients (absolute risk difference [RD] 0.7%, 95% CI -0.1 to 1.4%). At 1 year, moderate or severe paravalvular regurgitation increased to 3.4% of bicuspid patients and 2.1% of tricuspid patients (RD 1.3%, 95% CI -0.6 to 3.2%).

Conclusions:

In this registry, bicuspid and tricuspid AS patients at low surgical risk had similar rates of death and stroke following TAVR.

Perspective:

In the early days of TAVR, bicuspid aortic valve was considered a contraindication, given the risk of problems such as frame distortion and paravalvular regurgitation. Bicuspid AS was also an exclusion criterion for randomized trials of TAVR versus surgical AVR in low-risk patients. Nonetheless, bicuspid AS patients constitute a growing proportion of TAVR recipients, and this study illustrates that with newer-generation valves, TAVR in selected bicuspid AS patients yields favorable technical results and clinical outcomes. Limitations of this registry-based study include lack of a surgical comparator arm and data on Sievers type. The findings of this study are not generalizable to all bicuspid AS patients, some of whom have anatomic features such as extensive leaflet calcification that render TAVR less technically feasible.

Clinical Topics: Cardiac Surgery, Cardiovascular Care Team, Geriatric Cardiology, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Valvular Heart Disease, Aortic Surgery, Cardiac Surgery and VHD, Interventions and Imaging, Interventions and Structural Heart Disease, Echocardiography/Ultrasound

Keywords: Aortic Valve Stenosis, Bicuspid Aortic Valve Disease, Cardiac Surgical Procedures, Echocardiography, Geriatrics, Heart Valve Diseases, Heart Valve Prosthesis, Stroke, STS/ACC TVT Registry, Transcatheter Aortic Valve Replacement, Tricuspid Valve Stenosis


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