Micro-dislodgement during transcatheter aortic valve implantation with a contemporary self-expandable prosthesis

Factors Influencing Implantation Depth During Transcatheter Aortic Valve Replacement

Optimised implantation depth (OID) is crucial to obtain the best haemodynamic and clinical outcome during transcatheter heart valve (THV) deployment. OID ensures a better haemodynamic profile and is associated with a potential reduction in permanent pacemaker implantations, both of which are important during transcatheter aortic valve replacement (TAVR). Apart from patient-related anatomic conditions, many factors, such as THV and wire selection, as well as implantation strategies, can be controlled by the operator and facilitate the implantation process. However, there are only limited data dealing with predictors for OID. Therefore, the aim of this review was to outline factors and tools that might influence the final implantation depth during TAVR procedures, potentially influencing the outcome.

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.

Real-world experience with the cusp-overlap deployment technique in transcatheter aortic valve replacement: A propensity-matched analysis

Background

The implantation depth (ID) is a critical condition for optimal hemodynamic and clinical outcomes in transcatheter aortic valve replacement (TAVR). The recently recommended cusp-overlap technique (COT) offers optimized fluoroscopic projections facilitating a precise ID. This single-center observational study aimed to investigate short-term clinical performance, safety, and efficacy outcomes in patients undergoing TAVR with self-expandable prostheses and application of COT in a real-world setting.

Materials and methods

From September 2020 to April 2021, a total of 170 patients underwent TAVR with self-expandable devices and the application of COT, while 589 patients were treated from January 2016 to August 2020 with a conventional three-cusp coplanar view approach. The final ID and 30-day outcomes were compared after 1:1 propensity score matching, resulting in 150 patients in both cohorts.

Results

The mean ID was significantly reduced in the COT cohort (−4.2 ± 2.7 vs. −4.9 ± 2.3 mm; p = 0.007) with an improvement of ID symmetry of less than 2 mm difference below the annular plane (47.3 vs. 57.3%; p = 0.083). The rate of new permanent pacemaker implantation (PPI) following TAVR was effectively reduced (8.0 vs. 16.8%; p = 0.028). While the fluoroscopy time decreased (18.4 ± 7.6 vs. 19.8 ± 7.6 min; p = 0.023), the dose area product increased in the COT group (4951 ± 3662 vs. 3875 ± 2775 Gy × cm²; p = 0.005). Patients implanted with COT had a shorter length of in-hospital stay (8.4 ± 4.0 vs. 10.3 ± 6.7 days; p = 0.007).

Conclusion

Transcatheter aortic valve replacement using the cusp-overlap deployment technique is associated with an optimized implantation depth, leading to fewer permanent conduction disturbances. However, our in-depth analysis showed for the first time an increase of radiation dose due to extreme angulations of the gantry to obtain the cusp-overlap view.

Patient-Specific Computer Simulation to Predict Conduction Disturbance With Current-Generation Self-Expanding Transcatheter Heart Valves

Background

Patient-specific computer simulation may predict the development of conduction disturbance following transcatheter aortic valve replacement (TAVR). Validation of the computer simulations with current-generation devices has not been undertaken.

Methods

A retrospective study was performed on patients who had undergone TAVR with a current-generation self-expanding transcatheter heart valve (THV). Preprocedural computed tomography imaging was used to create finite element models of the aortic root. Procedural contrast angiography was reviewed, and finite element analysis performed using a matching THV device size and implantation depth. A region of interest corresponding to the atrioventricular bundle and proximal left bundle branch was identified. The percentage of this area (contact pressure index [CPI]) and maximum contact pressure (CPMax) exerted by THV were recorded. Postprocedural electrocardiograms were reviewed, and major conduction disturbance was defined as the development of persistent left bundle branch block or high-degree atrioventricular block.

Results

A total of 80 patients were included in the study. THVs were 23- to 29-mm Evolut PRO (n = 53) and 34-mm Evolut R (n = 27). Major conduction disturbance occurred in 27 patients (33.8%). CPI (28.3 ± 15.8 vs. 15.6 ± 11.2%; p < 0.001) and CPMax (0.51 ± 0.20 vs. 0.36 ± 0.24 MPa; p = 0.008) were higher in patients who developed major conduction disturbance. CPI (area under the receiver operating characteristic curve [AUC], 0.74; 95% CI, 0.63-0.86; p < 0.001) and CPMax (AUC, 0.69; 95% CI, 0.57-0.81; p = 0.006) demonstrated a discriminatory power to predict the development of major conduction disturbance.

Conclusions

Patient-specific computer simulation may identify patients at risk for conduction disturbance after TAVR with current-generation self-expanding THVs.

The Technological Basis of a Balloon-Expandable TAVR System: Non-occlusive Deployment, Anchorage in the Absence of Calcification and Polymer Leaflets

Leaflet durability and costs restrict contemporary trans-catheter aortic valve replacement (TAVR) largely to elderly patients in affluent countries. TAVR that are easily deployable, avoid secondary procedures and are also suitable for younger patients and non-calcific aortic regurgitation (AR) would significantly expand their global reach. Recognizing the reduced need for post-implantation pacemakers in balloon-expandable (BE) TAVR and the recent advances with potentially superior leaflet materials, a trans-catheter BE-system was developed that allows tactile, non-occlusive deployment without rapid pacing, direct attachment of both bioprosthetic and polymer leaflets onto a shape-stabilized scallop and anchorage achieved by plastic deformation even in the absence of calcification. Three sizes were developed from nickel-cobalt-chromium MP35N alloy tubes: Small/23 mm, Medium/26 mm and Large/29 mm. Crimp-diameters of valves with both bioprosthetic (sandwich-crosslinked decellularized pericardium) and polymer leaflets (triblock polyurethane combining siloxane and carbonate segments) match those of modern clinically used BE TAVR. Balloon expansion favors the wing-structures of the stent thereby creating supra-annular anchors whose diameter exceeds the outer diameter at the waist level by a quarter. In the pulse duplicator, polymer and bioprosthetic TAVR showed equivalent fluid dynamics with excellent EOA, pressure gradients and regurgitation volumes. Post-deployment fatigue resistance surpassed ISO requirements. The radial force of the helical deployment balloon at different filling pressures resulted in a fully developed anchorage profile of the valves from two thirds of their maximum deployment diameter onwards. By combining a unique balloon-expandable TAVR system that also caters for non-calcific AR with polymer leaflets, a powerful, potentially disruptive technology for heart valve disease has been incorporated into a TAVR that addresses global needs. While fulfilling key prerequisites for expanding the scope of TAVR to the vast number of patients of low- to middle income countries living with rheumatic heart disease the system may eventually also bring hope to patients of high-income countries presently excluded from TAVR for being too young.

Evolut Self-Expanding Transcatheter Aortic Valve Replacement in Patients with Extremely Horizontal Aorta (Aortic Root Angle ≥ 70°)

Because of its rigidity and non-steerability, the presence of a horizontal aortic root poses a major anatomical issue during transcatheter aortic valve replacement (TAVR) with Evolut self-expanding valve. Previous studies have elucidated the difficulties of coaxial implantation of the self-expanding valve in patients with horizontal aorta, often resulting in increased complications and a lower device success rate. To date, most patients with extremely horizontal aorta (aortic root angle ≥ 70°) have been excluded from major TAVR clinical trials. Therefore, available data on TAVR with Evolut in this challenging anatomy are limited, and standardized treatment strategies and clinical results remain unknown. Herein, we report a clinical case series of TAVR with Evolut in extremely horizontal aorta. Among seven patients (aged 80-92 years; STS score, 12.6% ± 7.9%) who underwent TAVR with Evolut system, aortic root angle ranged from 71° to 83° (mean, 75.1°± 4.5°). All patients achieved device success with dedicated strategies and were clinically stable at 3-month follow-up. None of the patients had more than mild paravalvular leakage (PVL) at any point during follow-up.Complications in three patients included complete atrioventricular block requiring a permanent pacemaker implantation, cerebral infarction because of atrial fibrillation 3 days after TAVR, and cardiac tamponade requiring pericardiocentesis. In this case series, Evolut self-expanding TAVR in extremely horizontal aorta was effective and feasible with a high device success rate. Based on anatomical features, some dedicated strategies majorly contribute to the success of this procedure. Large-scale multicenter studies are required to confirm our findings.