Supra-annular sizing of transcatheter aortic valve prostheses in raphe-type bicuspid aortic valve disease: the LIRA method

CharActeristics, sizing anD outcomes of stenotic, tapered, rapHe-type bicuspid aOrtic valves treated with trans-catheter device implantation: Insights the AD HOC registry

BACKGROUND

Raphe-type bicuspid aortic valve (BAV) is a potential hostile scenario in trans-catheter aortic valve replacement (TAVR) due to pronounced calcium burden, possibly associated with tapered valve configuration. Trans-Catheter heart valve (THV) sizing strategy (annular vs. supra-annular) is controversial in this valve subtype.

OBJECTIVES

To describe the phenotypical characteristics of severe, tapered, raphe-type, BAV stenosis undergoing TAVR and to explore safety and efficacy of modern-generation THVs, analysing the impact of annular and supra-annular sizing strategies on short- and mid-terms outcomes.

METHODS

This is a retrospective, multicenter registry enrolling consecutive stenotic Sievers type 1 BAV treated with TAVR. Study population was divided into tapered and non-tapered configuration according to MSCT analysis. Matched comparison between annular and supra-annular sizing groups was performed in tapered population.

RESULTS

From January 2016 to June 2023, 897 patients were enrolled. Of them, 696 patients displayed a tapered configuration. Of those, 510 received a THV according to annular sizing. After propensity score matching 186 matched pairs were selected. Technical success (96.2 % vs 94.1 %, OR 1.61 [0.61-4.24], p = 0.34), 30-day device success (83.6 % in both groups, OR 1.42 [0.78-2.57], p = 0.25) and 30-day early safety (71.8 % vs 70.5 %, OR 1.07 [0.68-1.68], p = 0.78) were similar between the annular and supra-annular sizing groups; a higher post-TAVR gradient was observed in supra-annular group, although it was only 2 mmHg mean. At mid-term follow-up, the rate of clinical efficacy was 84.7 %.

CONCLUSIONS

TAVR with modern-generation devices is safe and effective for tapered raphe-type BAV, showing comparable results for annular and supra-annular sizing strategies.

Comparable efficacy and safety for bicuspid aortic valve stenosis patients undergoing transcatheter aortic valve replacement with balloon-expandable or self-expanding valves using Wei's sizing method

BACKGROUND

The present study aimed to investigate whether proper sizing can improve the procedural and clinical outcomes of transcatheter aortic valve replacement (TAVR) with new-generation self-expanding valves (SEVs) and balloon-expandable valves (BEVs) for treating bicuspid aortic stenosis (BAS).

METHODS

We retrospectively evaluated consecutive patients who underwent TAVR with Sapien 3 valves (Edwards Lifesciences, Irvine, CA) or Evolut R/PRO valves (Medtronic, Minneapolis, MN) for severe BAS from 2017 to 2022. The primary endpoints were device success rate and major adverse cardiac and cerebral events (MACCEs), including mortality, nonfatal myocardial infarction or disabling stroke, transcatheter heart valve failure, or clinically relevant valve thrombosis during follow-up. Our team used a complementary approach of supraannular sizing in addition to the conventional annular sizing method (Wei's method) to guide the TAVR procedures.

RESULTS

We recruited a total of 75 consecutive patients, of whom 43 (57%) were treated with BEVs from October 2017 to June 2021, and 32 (43%) were treated with SEVs from July 2021 to December 2022. Device success was similar between the BEV and SEV groups (93% vs 94%; p > 0.99), and no cases of annular rupture occurred in either group. Similar rates of moderate-to-severe paravalvular leak were observed in the BEV and SEV groups (5% vs 6%, p > 0.99). At a median follow-up of 464 days, the MACCE rates were comparable between the two groups. In multivariate analysis, the presence of previous percutaneous coronary interventions (hazard ratio: 5.43; p = 0.039) and New York Heart Association functional class III/IV heart failure at 30 days of follow-up after TAVR (hazard ratio: 9.90; p = 0.037) were independently associated with long-term MACCEs.

CONCLUSION

Our results demonstrated comparable efficacy and safety for BAS patients undergoing TAVR using either BEVs or SEVs when using Wei's sizing method.

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).

Incidence, Predictors, and Outcomes of Paravalvular Regurgitation After TAVR in Sievers Type 1 Bicuspid Aortic Valves

BACKGROUND

Transcatheter aortic valve replacement (TAVR) in patients with bicuspid aortic valve (BAV) stenosis is technically challenging and is burdened by an increased risk of paravalvular regurgitation (PVR).

OBJECTIVES

The aim of this study was to identify the incidence, predictors, and clinical outcomes of PVR after TAVR in Sievers type 1 BAV stenosis.

METHODS

Consecutive patients with Sievers type 1 BAV stenosis undergoing TAVR with current-generation transcatheter heart valves (THVs) in 24 international centers were enrolled. PVR was graded as none/trace, mild, moderate, and severe according to echocardiographic criteria. The endpoint of major adverse events (MAEs), defined as a composite of all-cause death, stroke, or hospitalization for heart failure, was assessed at the last available follow-up.

RESULTS

A total of 946 patients were enrolled. PVR occurred in 423 patients (44.7%)-mild, moderate, and severe in 387 (40.9%), 32 (3.4%), and 4 (0.4%) patients, respectively. Independent predictors of moderate or severe PVR were a larger virtual raphe ring perimeter (adjusted OR: 1.07; 95% CI: 1.02-1.13), severe annular or left ventricular outflow tract calcification (adjusted OR: 5.21; 95% CI: 1.45-18.77), a self-expanding valve (adjusted OR: 9.01; 95% CI: 2.09-38.86), and intentional supra-annular THV positioning (adjusted OR: 3.31; 95% CI: 1.04-10.54). At a median follow-up of 1.3 years (Q1-Q3: 0.5-2.4 years), moderate or severe PVR was associated with an increased risk of MAEs (adjusted HR: 2.52; 95% CI: 1.24-5.09).

CONCLUSIONS

After TAVR with current-generation THVs in Sievers type 1 BAV stenosis, moderate or severe PVR occurred in about 4% of cases and was associated with an increased risk of MAEs during follow-up.

Mechanical behaviors of a new elliptical valve stent in bicuspid aortic valve

BACKGROUND AND OBJECTIVE

The conventional valve stents that are cylindrical in shape will become elliptical when implanted in bicuspid aortic valve, thereby reducing the durability of the artificial valve. In this study, a new design of valve stent is presented where valve stents have elliptical cross-section at the annulus and it is expected to have better expandability and circle shape during the interaction between the stent and bicuspid aortic valve, thereby extending the durability of artificial valve.

METHODS

Finite element method (FEM) is used to study the mechanical behavior of the novel valve stent in the bicuspid aortic valve. The effects of three matching relationship between the ellipticity of the stents and the ellipticity of the annulus (i.e., the ellipticity of the stent is greater than, equal to and less than the annulus ellipticity, respectively) on the mechanical behavior of stent expansion are studied. In addition, the expansion mechanical behavior of the novel valve stent at different implantation depths is also compared.

RESULTS

Results indicate that novel valve stent implantation with elliptical features is superior to conventional circular valve stent. When the novel valve stent ellipticity is less than the annulus ellipticity, the ellipticity of the novel valve stent after implantation is smaller than that of the conventional circular valve stent. This indicated that the novel valve stent has better expandability and post-expansion shape, making artificial valve to have better durability. The risk of paravalvular leak after implantation is lowest when the novel valve stent ellipticity is less than annulus ellipticity. When the novel valve stent ellipticity coincides with annulus ellipticity, the aortic wall is subjected to greatest stress. With the increase of implantation depth, the stress on the novel valve stent decrease.

CONCLUSIONS

This study might provide insights for improving stent design for bicuspid aortic valve.

Single-Center Experience with the Balloon-Expandable Myval Transcatheter Aortic Valve System in Patients with Bicuspid Anatomy: Procedural and 30-Day Follow-Up

Aims: To report our single-center data regarding the initial 52 consecutive patients with a bicuspid aortic valve who underwent a Transcatheter Aortic Valve Implantation (TAVI) procedure using the new balloon-expandable MYVAL system. The focus is on reporting procedural details and outcomes over the 30-day postoperative period. Methods: From December 2019 to July 2023, 52 consecutive patients underwent a TAVI procedure with bicuspid anatomy. All patients had moderate to-high surgical risk or were unsuitable for surgical aortic valve replacement based on the Heart Team's decision. Outcomes were analyzed according to the VARC-2 criteria. The results of bicuspid patients were compared to patients with tricuspid anatomy in the overall study group, and further analysis involved a comparison between 52 pairs after propensity score matching. The device performance was evaluated using transthoracic echocardiography. Data collection was allowed by the Local Ethical Committee. Results: The mean age was 71 ± 7.1 years, and 65.4% were male. The mean Euroscore II and STS score were 3.3 ± 3.2 and 5.2 ± 3.3, respectively. Baseline characteristics and echocardiographic parameters were well balanced even in the unmatched comparison. Procedures were significantly longer in the bicuspid group and resulted in a significantly higher ARI index. All relevant anatomic dimensions based on the CT scans were significantly higher in bicuspid anatomy, including a higher implantation angulation, a higher rate of horizontal aorta and a higher proportion of patients with aortopathy. In the unmatched bicuspid vs. tricuspid comparison, postprocedural outcomes were as follows: in-hospital mortality 0% vs. 1.4% (p = 0.394), device success 100% vs. 99.1% (p = 0.487), TIA 1.9% vs. 0% (p = 0.041), stroke 1.9% vs. 0.9% (p = 0.537), major vascular complication 3.8% vs. 2.3% (p = 0.530), permanent pacemaker implantation 34% vs. 30.4% (p = 0.429), and cardiac tamponade 0% vs. 0.5% (p = 0.624). In the propensity-matched bicuspid vs. tricuspid comparison, postprocedural outcomes were as follows: in-hospital mortality 0% vs. 0%, device success 100% vs. 100%, TIA 1.9% vs. 0% (p = 0.315), stroke 1.9% vs. 0.9% (p = 0.315), major vascular complication 3.8% vs. 0% (p = 0.475), permanent pacemaker implantation 34% vs. 24% (p = 0.274), and cardiac tamponade 0% vs. 0%. There was no annular rupture nor need for second valve or severe aortic regurgitation in both the unmatched and matched comparison. The peak and mean aortic gradients did not differ at discharge and at 30-day follow-up between the two groups regardless of whether the comparison was unmatched or matched. There were no paravalvular leakages (moderate or above) in the bicuspid patients. Intermediate and extra sizes of the Myval THV system used a significantly higher proportion in bicuspid anatomy with a significantly higher oversize percentage in tricuspid anatomy. Conclusions: The TAVI procedure using the Myval THV system in patients with significant aortic stenosis and bicuspid aortic valve anatomy is safe and effective. Hemodynamic parameters do not differ between tricuspid and bicuspid patients. However, the permanent pacemaker implantation rate is higher than expected; its relevance on long-term survival is controversial.

Transcatheter Aortic Valve Implantation for Bicuspid Aortic Valve Disease: Procedural Planning and Clinical Outcomes

Bicuspid aortic valve (BAV) is the most common congenital heart disease, with a prevalence of 1-2% and occurring in >20% of octogenarians referred for aortic valve replacement. However, BAV patients have been systematically excluded from pivotal randomized trials. Since TAVI indications are moving toward low-risk patients, an increase in the number of BAV patients who undergo TAVI is expected. BAV represents a challenge due to its unique morphological features (raphe, extreme asymmetrical valve calcifications, cusp asymmetry and aortopathy) and the lack of consensus about the accurate sizing method. The role of multi-slice computed tomography (MSCT) in the planification of the TAVI procedure is well-established, being useful to define the optimal valve sizing and the implantation strategy. New-generation devices, more experience of the operators and better planification of the procedure have been associated with similar clinical outcomes in bicuspid and tricuspid patients undergoing TAVI.

Comparison of patients with bicuspid and tricuspid aortic valve in transcatheter aortic valve implantation

BACKGROUND

Transcatheter aortic valve implantation (TAVI) has emerged as a safe and effective alternative to surgery for aortic stenosis (AS). However, there are still differences in the procedural process and outcome of bicuspid aortic valve (BAV) treated with TAVI compared with tricuspid aortic valve.

AREAS COVERED

This review paper aims to summarize the main characteristics and clinical evidence of TAVI in patients with bicuspid and tricuspid aortic valves and compare the outcomes of TAVI procedure.

EXPERT OPINION

The use of TAVI in patients with BAV has shown similar clinical outcomes compared with tricuspid aortic valve. The efficacy of TAVI for challenging BAV anatomies remains a concern due to the lack of randomized trials. Detailed preprocedural planning is of great importance in low-surgical-risk BAV patients. A better understanding of which subtypes of BAV anatomy are at greater risk for adverse outcomes can potentially benefit the selection of TAVI or open-heart surgery in low surgical risk AS patients.

Ongoing experience with patient-specific computer simulation of transcatheter aortic valve replacement in bicuspid aortic valve

BACKGROUND

Transcatheter aortic valve replacement (TAVR) is increasingly being used to treat younger, lower-risk patients with bicuspid aortic valve (BAV). Patient-specific computer simulation may identify patients at risk for developing paravalvular regurgitation (PVR) and major conduction disturbance. Only limited prospective experience of this technology exist. We wished to describe our ongoing experience with patient-specific computer simulation.

METHODS

Patients who were referred for consideration of TAVR with a self-expanding transcatheter heart valve (THV) and had BAV identified on pre-procedural cardiac computed tomography imaging underwent patient-specific computer simulation. The computer simulations were reviewed by the Heart Team and used to guide surgical or transcatheter treatment approaches and to aid in THV sizing and positioning. Clinical outcomes were recorded.

RESULTS

Between May 2019 and May 2021, 16 patients with BAV were referred for consideration of TAVR with a self-expanding THV. Sievers Type 1 morphology was present in 15 patients and Type 0 in the remaining patient. Two patients were predicted to develop moderate-to-severe PVR with a TAVR procedure and these patients underwent successful surgical aortic valve replacement. In the remaining 14 patients, computer simulation was used to optimize THV sizing and positioning to minimise PVR and conduction disturbance. One patient with a low valve implantation depth developed moderate PVR and this complication was correctly predicted by the computer simulations. No patient required insertion of a new permanent pacemaker.

CONCLUSION

Patient-specific computer simulation may be used to guide the most appropriate treatment modality for patients with BAV. The usage of computer simulation to guide THV sizing and positioning was associated with favourable clinical outcomes.

Designing a Novel Asymmetric Transcatheter Aortic Valve for Stenotic Bicuspid Aortic Valves Using Patient-Specific Computational Modeling

Bicuspid aortic valve (BAV), the most common congenital heart malformation, is characterized by the presence of only two valve leaflets with asymmetrical geometry, resulting in elliptical systolic opening. BAV often leads to early onset of calcific aortic stenosis (AS). Following the rapid expansion of transcatheter aortic valve replacement (TAVR), designed specifically for treating conventional tricuspid AS, BAV patients with AS were initially treated "off-label" with TAVR, which recently gained FDA and CE regulatory approval. Despite its increasing use in BAV, pathological BAV anatomy often leads to complications stemming from mismatched anatomical features. To mitigate these complications, a novel eccentric polymeric TAVR valve incorporating asymmetrical leaflets was designed specifically for BAV anatomies. Computational modeling was used to optimize its asymmetric leaflets for lower functional stresses and improved hemodynamic performance. Deployment and flow were simulated in patient-specific BAV models (n = 6) and compared to a current commercial TAVR valve (Evolut R 29 mm), to assess deployment and flow parameters. The novel eccentric BAV-dedicated valve demonstrated significant improvements in peak systolic orifice area, along with lower jet velocity and wall shear stress (WSS). This feasibility study demonstrates the clinical potential of the first known BAV-dedicated TAVR design, which will foster advancement of patient-dedicated valvular devices.

Transcatheter aortic valve implantation in patients with bicuspid valve morphology: a roadmap towards standardization

Indications for transcatheter aortic valve implantation (TAVI) have expanded in many countries to include patients with aortic stenosis who are at low surgical risk, and a similar expansion to this cohort is anticipated elsewhere in the world, together with an increase in the proportion of patients with bicuspid aortic valve (BAV) morphology as the age of the patients being treated decreases. To date, patients with BAV have been excluded from major randomized trials of TAVI owing to anatomical considerations. As a consequence, BAV has been a relative contraindication to the use of TAVI in international guidelines. Although clinical experience and observational data are accumulating, BAV presents numerous anatomical challenges for successful TAVI, despite advances in device design. Furthermore, in those with BAV, substantial geographical variation exists in patient characteristics, clinical approach and procedural strategy. Therefore, in this Roadmap article, we summarize the existing evidence and provide consensus recommendations from an international group of experts on the application of TAVI in patients with BAV in advance of the anticipated growth in the use of this procedure in this challenging cohort of patients.

Mind the gap: avoiding paravalvular leak using computer simulation in bicuspid transcatheter aortic valve replacement-a case report

Background

Transcatheter aortic valve replacement (TAVR) is becoming increasingly prevalent worldwide and is now more common than surgical aortic valve replacement. It is expanding into all patient subsets including younger and lower risk patients. Bicuspid aortic valve (BAV) accounts for a significant proportion of TAVR, but due to heterogenous anatomy, it is of increased complexity. One of the greatest challenges in BAV is the selection of the correct TAVR size. Transcatheter aortic valve replacement sizing is based upon computed tomography-derived annular measurements. There are a number of sizing algorithms for BAV based upon anatomical characteristics, often yielding different results. This is noted especially when a patient falls near the borderline between two valve sizes, an anatomical grey zone. Complementary to the algorithm approach is the use of pre-procedural patient-specific computer simulation using finite-element modelling.

Case summary

An 86-year-old female was treated for heart failure secondary to severe and calcific BAV aortic stenosis with TAVR. Due to anatomical difficulty and grey-zone valve sizing, we demonstrate the use of pre-procedural patient-specific computer simulation with the novel Medtronic Evolut PRO+ platform to achieve a good result.

Discussion

Using patient-specific computer simulation, we were able to safely select the valve and the deployment height and then accurately predict the result in a difficult, severely calcified BAV. In addition to improving outcome, this allows for patient-specific, tailored discussion to occur at heart team meetings.

Update on supra-annular sizing of transcatheter aortic valve prostheses in raphe-type bicuspid aortic valve disease according to the LIRA method

Recent evidence has shown that transcatheter heart valve (THV) anchoring in bicuspid aortic valve (BAV) patients occurs at the level of the raphe, known as the LIRA (Level of Implantation at the RAphe) plane. Our previous work in a cohort of 20 patients has shown that the delineation of the perimeter and device sizing at this level is associated with optimal procedural outcome. The goals of this study were to confirm the feasibility of this method, evaluate 30-day outcomes of LIRA sizing in a larger cohort of patients, assess interobserver variation and reproducibility of this sizing methodology, and analyse the interaction of LIRA-sized prostheses with the surrounding anatomy. The LIRA sizing method was applied to consecutive patients presenting to our centre with raphe-type BAV disease between November 2018 and October 2021. Supra-annular self-expanding THVs were sized based on baseline CT scan perimeters at the LIRA plane and the virtual basal ring. In cases where there was discrepancy between the two measurements, the plane with the smallest perimeter was considered the reference for prosthesis sizing. Post-procedural device success, defined according to Valve Academic Research Consortium-2 (VARC-2) criteria, was evaluated in the overall cohort. A total of 50 patients (mean age 80 ± 6 years, 70% male) with raphe-type BAV disease underwent transcatheter aortic valve replacement (TAVR) using different THV prostheses. The LIRA plane method appeared to be highly successful (100% VARC-2 device success) with no procedural mortality, no valve migration, no moderate-severe paravalvular leak, and low transprosthetic gradients (residual mean gradient 8.2 ± 3.4 mmHg). There were no strokes, no in-hospital or 30-day mortality, and an incidence of in-hospital pacemaker implantation of 10%. Furthermore, measurement of the LIRA plane perimeter was highly reproducible between observers (r = 0.980; P < 0.001) and predictive of the post-procedural prosthetic valve perimeter on CT scanning (r = 0.981; P < 0.001). We confirm the feasibility of supra-annular sizing using the LIRA method in a large cohort of patients with high procedural success and good clinical outcomes at 30 days. Application of the LIRA method optimizes THV prosthesis sizing in patients with raphe-type BAV disease.

The Presence of Calcified Raphe Is an Independent Predictor of Adverse Long-Term Clinical Outcomes in Patients With Bicuspid Aortic Stenosis Undergoing Transcatheter Aortic Valve Replacement

Objective

Current guidelines recommend that transcatheter aortic valve replacement (TAVR) for bicuspid aortic valve (BAV) with aortic stenosis (AS) should only be performed in selected patients. However, we consider it even more crucial to identify what the really important factors are while determining long-term outcomes in patients with BAV undergoing TAVR, which is precisely the aim of this study.

Methods

We retrospectively evaluated consecutive patients who underwent TAVR with balloon-expandable Sapien XT or Sapien 3 valves (Edwards Lifesciences, Irvine, CA) for the treatment of severe bicuspid AS. The primary end points were major adverse cardiac and cerebral events (MACCE), that is, mortality, non-fatal myocardial infarction (MI), disabling stroke, valve failure needing reintervention, or clinically relevant valve thrombosis during follow-up.

Results

A total of 56 patients who underwent TAVR with Sapien XT (n = 20) or Sapien 3 (n = 36) were included. The device and procedural success rates were similar between the two TAVR valves; however, the newer-generation Sapien 3 yielded a trend toward better long-term clinical outcomes than the early-generation Sapien XT did (MACCE rates 35 vs. 11%, p = 0.071). In the multivariate Cox proportional hazards analyses, the presence of calcified raphe > 4 mm was the only independent predictor of long-term MACCE (hazard ratio: 6.76; 95% confidence interval: 1.21–37.67, p = 0.029).

Conclusion

TAVR performed by a skilled heart team, while using newer-generation balloon-expandable Sapien 3 valve, may yield better long-term clinical outcomes compared to TAVR using early-generation Sapien XT valve. Moreover, the presence of calcified raphe >4 mm is an independent determinant of adverse clinical outcomes.

Bicuspid Valve Sizing for Transcatheter Aortic Valve Implantation: The Missing Link

Transcatheter aortic valve implantation (TAVI) is a well-recognized and established therapy for severe aortic stenosis, with expanding indications toward younger patients with low surgical risk profile. As bicuspid aortic valve (BAV) affects ~1-2% of the population, it may be speculated that an increasing number of patients with degenerated BAV may eventually need TAVI during the course of the disease. On the other hand, BAV represents a challenge due to its peculiar anatomical features and the lack of consensus on the optimal sizing strategy. The aim of this paper is to review the peculiar aspects of BAV and to discuss and compare the currently available sizing methods. Special attention is given to the role of pre-procedural imaging, mostly with multislice computed tomography, and to the aspects that operators should evaluate in order to ensure an optimal procedural planning and avoid procedural-related complications.

Safety and Efficacy of Myval Implantation in Patients with Severe Bicuspid Aortic Valve Stenosis-A Multicenter Real-World Experience

Bicuspid aortic valve (BAV) is the most common valvular congenital anomaly and is apparent in nearly 50% of candidates for AV replacement. While transcatheter aortic valve implantation (TAVI) is a recommended treatment for patients with symptomatic severe aortic stenosis (AS) at all surgical risk levels, experience with TAVI in severe bicuspid AS is limited. TAVI in BAV is still a challenge due to its association with multiple and complex anatomical considerations. A retrospective study has been conducted to investigate TAVI's procedural and 30-day outcomes using the Myval transcatheter heart valve (THV) (Meril Life Sciences Pvt. Ltd. Vapi, Gujarat, India) in patients with severe bicuspid AS. Data were collected on 68 patients with severe bicuspid AS who underwent TAVI with the Myval THV. Baseline characteristics, procedural, 30-day echocardiographic and clinical outcomes were collected. The mean age and STS PROM score were 72.6 ± 9.4 and 3.54 ± 2.1. Procedures were performed via the transfemoral route in 98.5%. Major vascular complications (1.5%) and life-threatening bleeding (1.5%) occurred infrequently. No patient had coronary obstruction, second valve implantation or conversion to surgery. On 30-day echocardiography, the mean transvalvular gradient and effective orifice area were 9.8 ± 4.5 mmHg and 1.8 ± 0.4 cm2, respectively. None/trace aortic regurgitation occurred in 76.5%, mild AR in 20.5% and moderate AR in 3%. The permanent pacemaker implantation rate was 8.5% and 30-day all-cause death occurred in 3.0% of cases. TAVI with the Myval THV in selected BAV anatomy is associated with favorable short-term hemodynamic and clinical outcomes.

The Predictors of Conduction Disturbances Following Transcatheter Aortic Valve Replacement in Patients With Bicuspid Aortic Valve: A Multicenter Study

Objective: To evaluate the predictors of new-onset conduction disturbances in bicuspid aortic valve patients using self-expanding valve and identify modifiable technical factors. Background: New-onset conduction disturbances (NOCDs), including complete left bundle branch block and high-grade atrioventricular block, remain the most common complication after transcatheter aortic valve replacement (TAVR). Methods: A total of 209 consecutive bicuspid patients who underwent self-expanding TAVR in 5 centers in China were enrolled from February 2016 to September 2020. The optimal cut-offs in this study were generated from receiver operator characteristic curve analyses. The infra-annular and coronal membranous septum (MS) length was measured in preoperative computed tomography. MSID was calculated by subtracting implantation depth measure on postoperative computed tomography from infra-annular MS or coronal MS length. Results: Forty-two (20.1%) patients developed complete left bundle branch block and 21 (10.0%) patients developed high-grade atrioventricular block after TAVR, while 61 (29.2%) patients developed NOCDs. Coronal MS <4.9 mm (OR: 3.08, 95% CI: 1.63-5.82, p = 0.001) or infra-annular MS <3.7 mm (OR: 2.18, 95% CI: 1.04-4.56, p = 0.038) and left ventricular outflow tract perimeter <66.8 mm (OR: 4.95 95% CI: 1.59-15.45, p = 0.006) were powerful predictors of NOCDs. The multivariate model including age >73 years (OR: 2.26, 95% CI: 1.17-4.36, p = 0.015), Δcoronal MSID <1.8 mm (OR: 7.87, 95% CI: 2.84-21.77, p < 0.001) and prosthesis oversizing ratio on left ventricular outflow tract >3.2% (OR: 3.42, 95% CI: 1.74-6.72, p < 0.001) showed best predictive value of NOCDs, with c-statistic = 0.768 (95% CI: 0.699-0.837, p < 0.001). The incidence of NOCDs was much lower (7.5 vs. 55.2%, p < 0.001) in patients without Δcoronal MSID <1.8 mm and prosthesis oversizing ratio on left ventricular outflow tract >3.2% compared with patients who had these two risk factors. Conclusion: The risk of NOCDs in bicuspid aortic stenosis patients could be evaluated based on MS length and prosthesis oversizing ratio. Implantation depth guided by MS length and reducing the oversizing ratio might be a feasible strategy for heavily calcified bicuspid patients with short MS.

Force distribution within the frame of self-expanding transcatheter aortic valve: Insights from in-vivo finite element analysis

We sought to assess the amount and distribution of force on the valve frame after transcatheter aortic valve replacement (TAVR) via patient-specific computer simulation. Patients successfully treated with the self-expanding Venus A-Valve and multislice computed tomography (MSCT) pre- and post-TAVR were retrospectively included. Patient-specific finite element models of the aortic root and prosthesis were constructed. The force (in Newton) on the valve frame was derived at every 3 mm from the inflow and at every 22.5° on each level. Twenty patients of whom 10 had bicuspid aortic valve (BAV) were analyzed. The total force on the frame was 74.9 N in median (interquartile range 24.0). The maximal force was observed at level 5 that corresponds with the nadir of the bioprosthetic leaflets and was 9.9 (7.1) N in all patients, 10.3 (6.6) N in BAV and 9.7 (9.2) N for patients with tricuspid aortic valve (TAV). The level of maximal force located higher from the native annulus in BAV and TAV patients (8.8 [4.8] vs. 1.8 [7.4] mm). The area of the valve frame at the level of maximal force decreased from 437.4 (239.7) mm² at the annulus to 377.6 (114.3) mm² in BAV, but increased from 397.5 (114.3) mm² at the annulus to 406.7 (108.9) mm² in TAV. The maximum force on the bioprosthetic valve frame is located at the plane of the nadir of the bioprosthetic leaflets. It remains to be elucidated whether this may be associated with bioprosthetic frame and leaflet integrity and/or function.

Aortic annulus sizing in bicuspid and tricuspid aortic valves using CT in patients with surgical aortic valve replacement

The purpose of this study was to evaluate whether bicuspid anatomy affects the discrepancy between CT-derived annular size and intraoperative size. We retrospectively analyzed annular measurements in 667 patients who underwent surgical aortic valve replacement (AVR). Preoperative CT measurements of the aortic annulus were compared to surgically implanted valve sizes. To evaluate whether the bicuspid valve affects the differences between CT annulus diameter and surgical AVR size, patients with diameter larger by > 10% (CT-Lg group) on CT, compared to surgical AVR size, were compared with those having size difference < 10% (CT-Sim group). Propensity score matching yielded 183 matched patients from each group. Bicuspid aortic valve annulus parameters significantly correlated with surgical aortic valve size (r = 0.52-0.71; for all, p < 0.01). The most representative measurements corresponded to surgical aortic valve size were area-derived diameters in tricuspid aortic valve (r = 0.69, p < 0.001) and bicuspid without raphe (r = 0.71, p < 0.001), and perimeter-derived diameter in bicuspid with raphe (r = 0.63, p < 0.001). After propensity score matching, native valve type was not different between CT-Sim and CT-Lg groups. In multivariable analysis, the difference between CT-derived diameter and surgical AVR size was affected by the operator factor and types of prosthesis. Bicuspid aortic annulus diameters measured on CT showed a significant correlation with surgical aortic valve size. The difference between CT-derived diameter and surgical AVR size is affected by operator factor and the types of prosthesis but not affected by the bicuspid valve.

Transcatheter Aortic Valve Replacement for Bicuspid Aortic Valve Stenosis: A Practical Operative Overview

The bicuspid aortic valve (BAV) represents a complex anatomic scenario for transcatheter aortic valve replacement (TAVR) because of its unique technical challenges. As TAVR is moving towards younger and lower-risk populations, the proportion of BAV patients undergoing TAVR is expected to rise. Initial experiences of TAVR with first-generation transcatheter heart valves in high surgical risk patients with BAV stenosis showed higher rates of device failure and periprocedural complications as compared to tricuspid anatomy. The subsequent advances in imaging techniques and understanding of BAV anatomy, new iterations of transcatheter heart valves, and growing operators' experience yielded better outcomes. However, in the lack of randomized trials and rigorous evidence, the field of TAVR in BAV has been driven by empirical observations, with wide variability in transcatheter heart valve sizing and implantation techniques across different centers and operators. Thus, in this review article, we provide a fully illustrated overview of operative periprocedural steps for TAVR in BAV stenosis, though recognizing that it still remains anecdotal.