Transcatheter Aortic Valve Implantation in Sievers Type 0 vs. Type 1 Bicuspid Aortic Valve Morphology: Systematic Review and Meta-Analysis

Two-year follow-up of transcatheter aortic valve replacement in low-risk patients with symptomatic severe bicuspid aortic valve stenosis

BACKGROUND

In 2019, the US Food and Drug Administration (FDA) approved transcatheter aortic valve replacement (TAVR) for low-risk patients with symptomatic severe tricuspid aortic stenosis. However, bicuspid aortic valve (BAV) patients were included only in single-arm registries of pivotal low-risk TAVR trials, resulting in limited data for this subgroup.

METHODS

The LRT (Low Risk TAVR) trial was an investigator-initiated, prospective, multicenter study and the first FDA-approved investigational device exemption trial to evaluate the feasibility of TAVR with balloon-expandable or self-expanding valves in low-risk patients with symptomatic severe BAV stenosis. This analysis reports 2-year follow-up, assessing the primary outcome of all-cause mortality and evaluating clinical outcomes.

RESULTS

From 2016 to 2019, a total of 72 low-risk patients diagnosed with symptomatic, severe BAV stenosis underwent TAVR across six centers. Six patients were lost to follow-up. At 2-year follow-up, mortality was 1.5% (1 of 66 patients). Among the remaining 65 patients, four experienced nondisabling strokes (6.2%), while 2 (3.1%) developed infective endocarditis. No new permanent pacemakers were required beyond the 30-day follow-up, and no patients, including those with endocarditis, needed aortic valve re-intervention. At the 2-year echocardiography follow-up (n = 65), 27.8% of BAV patients showed mild aortic regurgitation, with none exhibiting moderate or severe regurgitation. The mean aortic gradient was 12.1 ± 4.1 mmHg, and the mean valve area was 1.7 ± 0.5 cm².

CONCLUSION

The 2-year follow-up confirms commendable clinical outcomes of TAVR in patients with bicuspid aortic stenosis, establishing its evident safety.

Comparison of downsizing strategy (HANGZHOU Solution) and standard annulus sizing strategy in type 0 bicuspid aortic stenosis patients undergoing transcatheter aortic valve replacement: Rationale and design of a randomized clinical trial

BACKGROUND

There has not been a consensus on the prothesis sizing strategy in type 0 bicuspid aortic stenosis (AS) patients undergoing transcatheter aortic valve replacement (TAVR). Modifications to standard annular sizing strategies might be required due to the distinct anatomical characteristics. We have devised a downsizing strategy for TAVR using a self-expanding valve specifically for patients with type 0 bicuspid AS. The primary aim of this study is to compare the safety and efficacy of downsizing strategy with the Standard Annulus Sizing Strategy in TAVR for patients with type 0 bicuspid AS.

TRIAL DESIGN

It is a prospective, multi-center, superiority, single-blinded, randomized controlled trial comparing the Down Sizing and Standard Annulus Sizing Strategy in patients with type 0 bicuspid aortic stenosis undergoing transcatheter aortic valve replacement. Eligible participants will include patients with severe type 0 bicuspid AS, as defined by criteria such as mean gradient across aortic valve ≥40 mmHg, peak aortic jet velocity ≥4.0 m/s, aortic valve area (AVA) ≤1.0 cm², or AVA index ≤0.6 cm2/m2. These patients will be randomly assigned, in a 1:1 ratio, to either the Down Sizing Strategy group or the Standard Sizing Strategy group. In the Down Sizing Strategy group, a valve one size smaller will be implanted if the "waist sign" manifests along with less than mild regurgitation during balloon pre-dilatation. The primary end point of the study is a composite of VARC-3 defined device success, absence of both permanent pacemaker implantation due to high-degree atrioventricular block and new-onset complete left bundle branch block.

CONCLUSION

This study will compare the safety and efficacy of Down Sizing Strategy with the Standard Annulus Sizing Strategy and provide valuable insights into the optimal approach for sizing in TAVR patients with type 0 bicuspid AS. We hypothesize that the Down Sizing Strategy will demonstrate superiority when compared to the Standard Annulus Sizing Strategy. (Down Sizing Strategy (HANGZHOU Solution) vs Standard Sizing Strategy TAVR in Bicuspid Aortic Stenosis (Type 0) (TAILOR-TAVR), NCT05511792).

Pooled-Analysis of Association of Sievers Bicuspid Aortic Valve Morphology With New Permanent Pacemaker and Conduction Abnormalities After Transcatheter Aortic Valve Replacement

Background

Studies on the association of Sievers bicuspid aortic valve (BAV) morphology with conduction disorders after transcatheter aortic valve replacement (TAVR) have not reached consensus.

Methods

We here performed a pooled-analysis to explore whether Sievers type 1 BAV morphology increased the risk of post-TAVR conduction abnormalities and permanent pacemaker implantation (PPI) compared to type 0. Systematic literature searches through EMBASE, Medline, and Cochrane databases were concluded on 1 December 2021. The primary endpoint was post-TAVR new PPI and pooled as risk ratios (RRs) and 95% confidence intervals (CIs). Conduction abnormalities as the secondary endpoint were the composites of post-TAVR PPI and/or new-onset high-degree of atrial-ventricle node block and left-bundle branch block. Studies that reported incidence of outcomes of interest in both type 1 and type 0 BAV morphology who underwent TAVR for aortic stenosis were included.

Results

Finally, nine studies were included. Baseline characteristics were generally comparable, but type 1 population was older with a higher surgical risk score compared to type 0 BAV morphology. In the pooled-analysis type 1 BAV had significantly higher risk of post-TAVR new-onset conduction abnormalities (RR = 1.68, 95%CI 1.09–2.60, p = 0.0195) and new PPI (RR = 1.97, 95%CI 1.29–2.99, p = 0.0016) compared to type 0. Random-effects univariate meta-regression indicated that no significant association between baseline characteristics and PPI.

Conclusion

Sievers type 1 BAV morphology was associated with increased risk of post-TAVR PPI and conduction abnormalities compared to type 0. Dedicated cohort is warranted to further validate our hypothesis.