Understanding the Interaction Between Transcatheter Aortic Valve Prostheses and Supra-Annular Structures From Post-Implant Stent Geometry

Snaring Self-Expanding Devices to Facilitate Transcatheter Aortic Valve Replacement in Patients with Complex Aortic Anatomies

The snare-assisted technique has been described to facilitate transcatheter aortic valve replacement (TAVR) delivery system advancement in complex aortic anatomies. However, the evidence is limited to case reports. To evaluate the safety profile of the snare-facilitated approach and its impact on self-expanding (SE) TAVR outcomes, we collected consecutive patients who underwent transfemoral SE-TAVR for aortic stenosis, using propensity score matching (PSM) separately in tricuspid and type-0 and type-1 bicuspid aortic valve morphology between the snare and non-snare groups. In 766 patients, despite the snare group having significantly larger annulus angulation and maximal ascending aortic diameter, both groups achieved comparable 30-day device success rates, regardless of first-generation or new-generation valve use. After PSM, the snare group had a significantly lower new permanent pacemaker implantation rate among 193 type-0 patients (3.3% vs. 18.3%, p = 0.01). The ipsilateral group used new-generation valves less frequently (23.0% vs. 75.4%, p < 0.001), but there were no significant inter-group differences in procedure-related events, except for a lower incidence of PVL ≥ mild in the ipsilateral group (14.9% vs. 32.3%, p = 0.01). In conclusion, the snare-assisted technique appears useful in SE-TAVR with angulated aortic root anatomy, and the benefits were comparable between ipsilateral and contralateral snare techniques.

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.

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.

Anatomical morphology of the aortic valve in Chinese aortic stenosis patients and clinical results after downsize strategy of transcatheter aortic valve replacement

BACKGROUND

The study aimed to describe the aortic valve morphology in Chinese patients underwent transcatheter aortic valve replacement (TAVR) for symptomatic severe aortic stenosis (AS), and the impact of sizing strategies and related procedural outcomes.

METHODS

Patients with severe AS who underwent TAVR were consecutively enrolled from 2012 to 2019. The anatomy and morphology of the aortic root were assessed. "Downsize" strategy was preformed when patients had complex morphology. The clinical outcomes of patients who performed downsize strategy were compared with those received annular sizing strategy. The primary outcome was device success rate, and secondary outcomes included Valve Academic Research Consortium-3 clinical outcomes variables based on 1-year follow-up.

RESULTS

A total of 293 patients were enrolled. Among them, 95 patients (32.4%) had bicuspid aortic valve. The calcium volume (Hounsfield Unit-850) of aortic root was 449.90 (243.15-782.15) mm 3 . Calcium is distributed mostly on the leaflet level. Downsize strategy was performed in 204 patients (69.6%). Compared with the patients who performed annular sizing strategy, those received downsize strategy achieved a similar device success rate (82.0% [73] vs . 83.3% [170], P  = 0.79). Aortic valve gradients (downsize strategy group vs . annular sizing group, 11.28 mmHg vs. 11.88 mmHg, P  = 0.64) and percentages of patients with moderate or severe paravalvular regurgitation 2.0% (4/204) vs . 4.5% (4/89), P  = 0.21) were similar in the two groups at 30 days after TAVR. These echocardiographic results were sustainable for one year.

CONCLUSIONS

Chinese TAVR patients have more prevalent bicuspid morphology and large calcium volume of aortic root. Calcium is distributed mostly on the leaflet level. Compare with annular sizing strategy, downsize strategy provided a non-inferior device success rate and transcatheter heart valve hemodynamic performance in self-expanding TAVR procedure.

The Chinese Experience of Imaging in Cardiac Intervention: A Bird's Eye Review

Recent scientific and technological advances have greatly contributed to the development of medical imaging that could enable specific functions. It has become the primary focus of cardiac intervention in preoperative assessment, intraoperative guidance, and postoperative follow-up. This review provides a contemporary overview of the Chinese experience of imaging in cardiac intervention in recent years.

Bicuspid Aortic Valve Stenosis: From Pathophysiological Mechanism, Imaging Diagnosis, to Clinical Treatment Methods

Bicuspid aortic valve (BAV) is the most frequent congenital anomaly and has a natural evolution toward aortic regurgitation or stenosis due to the asymmetrical valve function associated with an evolutive ascending aortopathy. Several BAV classifications exist describing the presence and number of raphe, amount and location of calcium, and the symmetry of the functional cusps. The impact of BAV morphology on transcatheter aortic valve implantation (TAVI) outcomes still remains little investigated. Pivotal randomized trials comparing TAVI with surgery have excluded BAV until yet. However, data from registries and observational studies including highly selected patients have shown promising results of TAVI in BAV. With this review, we aimed at describing anatomical and pathophysiological characteristics of BAV, discussing the main aspects to assess diagnostic imaging modalities, and giving an overview of TAVI outcomes and technical considerations specific to BAV morphology.

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.

The incidence and predictors of high-degree atrioventricular block in patients with bicuspid aortic valve receiving self-expandable transcatheter aortic valve implantation

BACKGROUND

The high-degree atrioventricular block (HAVB) in patients with bicuspid aortic valve (BAV) treated with transcatheter aortic valve implantation (TAVI) remains high. The study aims to explore this poorly understood subject of mechanisms and predictors for HAVB in BAV self-expandable TAVI patients.

METHODS

We retrospectively included 181 BAV patients for analysis. Using computed tomography data, the curvature of ascending aorta (AAo) was quantified by the angle (AAo angle) between annulus and the cross-section at 35 mm above annulus (where the stent interacts with AAo the most). The valvular anatomy and leaflet calcification were also characterized.

RESULTS

The 30-day HAVB rate was 16.0% (median time to HAVB was three days). Type-1 morphology was found in 79 patients (43.6%) (left- and right-coronary cusps fusion comprised 79.7%). Besides implantation below membrane septum, large AAo angle [odds ratio (OR) = 1.08, P = 0.016] and type-1 morphology (OR = 4.97, P = 0.001) were found as the independent predictors for HAVB. Together with baseline right bundle branch block, these predictors showed strong predictability for HAVB with area under the cure of 0.84 (sensitivity = 62.1%, specificity = 92.8%). Bent AAo and calcified raphe had a synergistic effect in facilitating high implantation, though the former is associated with at-risk deployment (device implanted above annulus + prothesis pop-out, versus straight AAo: 9.9% vs. 2.2%, P = 0.031).

CONCLUSIONS

AAo curvature and type-1 morphology are novel predictors for HAVB in BAV patients following self-expandable TAVI. For patients with bent AAo or calcified raphe, a progressive approach to implant the device above the lower edge of membrane septum is favored, though should be done cautiously to avoid pop-out.

Sealing Behavior in Transcatheter Bicuspid and Tricuspid Aortic Valves Replacement Through Patient-Specific Computational Modeling

Background: Patient-specific computer simulation of transcatheter aortic valve replacement (TAVR) can provide unique insights in device-patient interaction. Aims: This study was to compare transcatheter aortic valve sealing behavior in patients with bicuspid aortic valves (BAV) and tricuspid aortic valves (TAV) through patient-specific computational modeling. Methods: Patient-specific computer simulation was retrospectively performed with FEops HEARTguide for TAVR patients. Simulation output was compared with postprocedural computed tomography and echocardiography to validate the accuracy. Skirt malapposition was defined by a distance larger than 1 mm based on the predicted device-patient interaction by quantifying the distance between the transcatheter heart valve (THV) skirt and the surrounding anatomical regions. Results: In total, 43 patients were included in the study. Predicted and observed THV frame deformation showed good correlation (R 2 ≥ 0.90) for all analyzed measurements (maximum diameter, minimum diameter, area, and perimeter). The amount of predicted THV skirt malapposition was strongly linked with the echocardiographic grading of paravalvular leakage (PVL). More THV skirt malapposition was observed for BAV cases when compared to TAV cases (22.7 vs. 15.5%, p < 0.05). A detailed analysis of skirt malapposition showed a higher degree of malapposition in the interleaflet triangles section for BAV cases as compared to TAV patients (11.1 vs. 5.8%, p < 0.05). Conclusions: Patient-specific computer simulation of TAVR can accurately predict the behavior of the Venus A-valve. BAV patients are associated with more malapposition of the THV skirt as compared to TAV patients, and this is mainly driven by more malapposition in the interleaflet triangle region.

Treatment of Bicuspid Aortic Valve Stenosis Using Transcatheter Heart Valves

The paucity of data regarding the use of transcatheter aortic valve replacement (TAVR) in bicuspid aortic valve (BAV) anatomy due to exclusion from pivotal studies and lack of studies assessing the long-term outcomes and valve performance continue to present a significant challenge as we expand TAVR to patients with BAV anatomy. This article discusses the important anatomic and clinical considerations in the selection and management of patients with BAV with TAVR and reviews the emerging evidence that increasingly suggests this procedure is safe, device success is excellent, and procedural outcomes are improving.

Effect of Eccentric Calcification of an Aortic Valve on the Implant Depth of a Venus-A Prosthesis During Transcatheter Aortic Valve Replacement: A Retrospective Study

Object

Our goal was to assess the implant depth of a Venus-A prosthesis during transcatheter aortic valve replacement (TAVR) when the areas of eccentric calcification were distributed in different sections of the aortic valve.

Methods

A total of 53 patients with eccentric calcification of the aortic valve who underwent TAVR with a Venus-A prosthesis from January 2018 to November 2019 were retrospectively analyzed. The patients were divided into three groups (A, B, and C) according to the location of the eccentric calcification, which was determined by preprocedural computerized tomography angiography (CTA) images. The prosthesis release process and position were evaluated by contrast aortography during TAVR, and the differences in valve implant depths were compared among the three groups. The effects of different aortic root structures and procedural strategies on prosthesis implant depth were analyzed.

Results

Eleven patients had eccentric calcification in region A; 19 patients, in region B; and 23 patients, in region C. The patients with eccentric calcification in region B had a higher risk of prosthesis migration (10.5% upward and 21.1% downward), and the position of the prosthesis after TAVR in group B was the deepest among the three groups. When eccentric calcification was located in region A or C, the prosthesis was released at the standard position with more stability, and the location of the prosthesis was less deep after TAVR (region A: 4.12 ± 3.4 mm; region B: 10.2 ± 5.3 mm; region C: 8.4 ± 4.0 mm; region A vs. region B, P = 0.0004; region C vs. region B; and P = 0.0360). In addition, the left ventricular outflow tract (LVOT) (P = 0.0213) and aortic root angulation (P = 0.0263) also had a significant effect on implant depth in the aortic root structure of the patients. The prosthesis size was 28.3 ± 2.4 in the deep implant group and 26.4 ± 2.0 in the appropriate implant group (P = 0.0068).

Conclusion

The implant depth of the Venus-A prosthesis is closely related to the distribution of eccentric calcification in the aortic valve during TAVR. Surgeons should adjust the surgical strategy according to aortic root morphology to prevent prosthesis migration.

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.

Expert Consensus on Sizing and Positioning of SAPIEN 3/Ultra in Bicuspid Aortic Valves

Severe aortic stenosis patients with bicuspid anatomy have been excluded from the major transcatheter aortic valve replacement (TAVI) randomized clinical trials. As a result, there is no official recommendation on bicuspid TAVI. A panel of bicuspid experts was created to fill this gap. In this consensus statement, an algorithm is proposed to guide the choice of surgery or TAVI within this complex patient population, depending on aortic dilatation, age, surgical risk score, and anatomy. A step-by-step guide for sizing and positioning of the SAPIEN 3/Ultra TAVI bioprostheses is presented. Annular sizing remains the primary strategy in most bicuspid patients. However, some anatomies may require sizing at the supra-annular level, for which patients the panel recommends the circle method, a dedicated sizing and positioning approach for SAPIEN 3/Ultra. The consensus provides valuable pre-operative insights on the interactions between SAPIEN 3/Ultra and the bicuspid anatomy; understanding the valve–anatomy relationship is critical to avoid complications and to optimize outcomes for patients.

Transcatheter Aortic Valve Replacement in Bicuspid Aortic Valve Stenosis

After 15 years of successive randomized, controlled trials, indications for transcatheter aortic valve replacement (TAVR) are rapidly expanding. In the coming years, this procedure could become the first line treatment for patients with a symptomatic severe aortic stenosis and a tricuspid aortic valve anatomy. However, randomized, controlled trials have excluded bicuspid aortic valve (BAV), which is the most frequent congenital heart disease occurring in 1% to 2% of the total population and representing at least 25% of patients 80 years of age or older referred for aortic valve replacement. The use of a less invasive transcatheter therapy in this elderly population became rapidly attractive, and approximately 10% of patients currently undergoing TAVR have a BAV. The U.S. Food and Drug Administration and the "European Conformity" have approved TAVR for low-risk patients regardless of the aortic valve anatomy whereas international guidelines recommend surgical replacement in BAV populations. Given this progressive expansion of TAVR toward younger and lower-risk patients, heart teams are encountering BAV patients more frequently, while the ability of this therapy to treat such a challenging anatomy remains uncertain. This review will address the singularity of BAV anatomy and associated technical challenges for the TAVR procedure. We will examine and summarize available clinical evidence and highlight critical knowledge gaps regarding TAVR utilization in BAV patients. We will provide a comprehensive overview of the role of computed tomography scans in the diagnosis, and classification of BAV and TAVR procedure planning. Overall, we will offer an integrated framework for understanding the current role of TAVR in the treatment of bicuspid aortic stenosis and for guiding physicians in clinical decision-making.

Treating patients with excessively large annuli with self-expanding transcatheter aortic valves: insights into supra-annular structures that anchor the prosthesis

BACKGROUND

Some patients referred for transcatheter aortic valve replacement (TAVR) have excessively large annuli (ELA) without device options according to current sizing charts. This retrospective study aims to summarize the presentation and outcomes of ELA patients receiving first-generation self-expanding valves.

METHODS

The TAVR database was reviewed in search for cases of self-expanding valves. Patients who had annuli exceeding the perimeter limit on the device sizing chart were referred to as the ELA group. Patients who had annuli within the range covered by the two largest sizes and received the corresponding valve size served as the control group (CG). Baseline, procedures, outcomes, and imaging characteristics on multislice computed tomography (MSCT), such as native anatomy and postimplant stent geometry, were compared.

RESULTS

A total of 28 patients were included in the ELA group and 82 in the CG. The patients in the ELA group were younger than those in the CG (72.5 ± 6.2 vs. 75.4 ± 5.8 years, P = 0.03). The median intended perimeter oversizing in relation to the annulus in the ELA group was much smaller than in the CG (-0.4 [-4.6, 4.1] % vs. 16.1 [11.7, 20.8] %, P < 0.01). The calcium burden in the aortic root was around 1.3-fold greater in the ELA group than the CG (756.0 [534.5, 1670.9] vs. 582.1 [310.3, 870.9] mm³, P = 0.01). The need for second valve implantation was higher in ELA (21.4% vs. 12.2%, P = 0.23) but no valve embolization was encountered. The 1‑year follow-up was comparable, including >mild paravalvular leak.

CONCLUSION

Under cautious patient selection using MSCT, TAVR with self-expanding valves in patients with ELA appears feasible. Supra-annular structures likely provide the extra anchoring.