Can we reduce conduction disturbances following transcatheter aortic valve replacement?

Platform Selection for Patients Undergoing Transcatheter Aortic Valve Replacement: A Practical Approach

Transfemoral transcatheter aortic valve Replacement (TAVR) has become the standard therapy for patients with severe aortic stenosis in patients over 75 years old in Europe or 65 years old in the United States, regardless of the surgical risk. Furthermore, iterations of existing transcatheter aortic valves (TAVs), as well as devices with novel concepts, have provided substantial improvements with respect to the limitations of previous-generation devices. Hence, treatment of a broader spectrum of patients has become feasible, and a sophisticated selection of the appropriate TAV tailored to patients' anatomy and comorbidities is now possible. Anatomy, patient characteristics, and operator experience must all inform proper device selection. This review describes the features and performance of the current generation of TAVs with the aim of providing a practical approach for clinicians when selecting the appropriate TAV for a specific patient.

Conduction Disturbances After Transcatheter Aortic Valve Replacement: An Update on Epidemiology, Preventive Strategies, and Management

Conduction disturbances (CDs) are common after transcatheter aortic valve replacement. Continuous improvements in preprocedural planification, implant techniques, and device design have markedly reduced periprocedural complications. However, CDs rate remains in the double-digit range. Because CDs after TAVR are associated with poorer outcomes, seeking a reduction in their occurrence is paramount. Several nonmodifiable and modifiable factors are associated with an increased risk of CDs. Previous right bundle branch block has been shown to have a strong association with pacemaker implant after TAVR. Among the modifiable factors, a lower implantation depth seems to be associated with a higher risk of CDs, and several implant strategies aiming to obtain a higher implant depth have shown promising results. This literature review provides a detailed description of updated evidence about the epidemiology, impact, and preventive and management strategies of CDs after TAVR. Also, based on these updated data, a fast-track protocol CDs management is proposed.

Validation evidence with experimental and clinical data to establish credibility of TAVI patient-specific simulations

PURPOSE

The objective of this study is to validate a novel workflow for implementing patient-specific finite element (FE) simulations to virtually replicate the Transcatheter Aortic Valve Implantation (TAVI) procedure.

METHODS

Seven patients undergoing TAVI were enrolled. Patient-specific anatomical models were reconstructed from pre-operative computed tomography (CT) scans and subsequentially discretized, considering the native aortic leaflets and calcifications. Moreover, high-fidelity models of CoreValve Evolut R and Acurate Neo2 valves were built. To determine the most suitable material properties for the two stents, an accurate calibration process was undertaken. This involved conducting crimping simulations and fine-tuning Nitinol parameters to fit experimental force-diameter curves. Subsequently, FE simulations of TAVI procedures were conducted. To validate the reliability of the implemented implantation simulations, qualitative and quantitative comparisons with post-operative clinical data, such as angiographies and CT scans, were performed.

RESULTS

For both devices, the simulation curves closely matched the experimental data, indicating successful validation of the valves mechanical behaviour. An accurate qualitative superimposition with both angiographies and CTs was evident, proving the reliability of the simulated implantation. Furthermore, a mean percentage difference of 1,79 ± 0,93 % and 3,67 ± 2,73 % between the simulated and segmented final configurations of the stents was calculated in terms of orifice area and eccentricity, respectively.

CONCLUSION

This study shows the successful validation of TAVI simulations in patient-specific anatomies, offering a valuable tool to optimize patients care through personalized pre-operative planning. A systematic approach for the validation is presented, laying the groundwork for enhanced predictive modeling in clinical practice.

Evolving Devices and Material in Transcatheter Aortic Valve Replacement: What to Use and for Whom

Transcatheter aortic valve replacement (TAVR) has revolutionized the treatment of aortic stenosis, providing a viable alternative to surgical aortic valve replacement (SAVR) for patients deemed to be at prohibitive surgical risk, but also for selected patients at intermediate or low surgical risk. Nonetheless, there still exist uncertainties regarding the optimal management of patients undergoing TAVR. The selection of the optimal bioprosthetic valve for each patient represents one of the most challenging dilemmas for clinicians, given the large number of currently available devices. Limited follow-up data from landmark clinical trials comparing TAVR with SAVR, coupled with the typically elderly and frail population of patients undergoing TAVR, has led to inconclusive data on valve durability. Recommendations about the use of one device over another in given each patient’s clinical and procedural characteristics are largely based on expert consensus. This review aims to evaluate the available evidence on the performance of different devices in the presence of specific clinical and anatomic features, with a focus on patient, procedural, and device features that have demonstrated a relevant impact on the risk of poor hemodynamic valve performance and adverse clinical events.

Pre-dilation and Post-dilation in Transcatheter Aortic Valve Replacement: Indications, Benefits and Risks

Transcatheter aortic valve replacement (TAVR) is an established treatment for patients with symptomatic severe aortic stenosis. In recent years, an emphasis has been placed on simplification of the procedure. Balloon predilation was initially considered a mandatory step to cross and prepare the stenotic aortic valve, but several studies demonstrated the feasibility of performing TAVR without balloon valvuloplasty. Balloon postdilation of the implanted valve is sometimes required to optimise results, although many patients do not require this step. Contemporary consensus advocates an individualised approach to TAVR procedures and so balloon pre- and post-dilation are performed selectively. This review aims to outline the advantages and disadvantages of balloon pre- and post-dilation and to identify the scenarios in which they are required during TAVR procedures.

Pacemaker dependency after transcatheter aortic valve replacement compared to surgical aortic valve replacement

Transcatheter aortic valve replacement (TAVR) is a standard treatment indicated for severe aortic stenosis in high-risk patients. The objective of this study was to evaluate the incidence of pacemaker dependency after permanent pacemaker implantation (PPI) following TAVR or surgical aortic valve replacement (SAVR) and the risk of mortality at a tertiary center in Korea.In this retrospective study conducted at a single tertiary center, clinical outcomes related to pacemaker dependency were evaluated for patients implanted with pacemakers after TAVR from January 2012 to November 2018 and post-SAVR from January 2005 to May 2015. Investigators reviewed patients' electrocardiograms and baseline rhythms as well as conduction abnormalities. Pacemaker dependency was defined as a ventricular pacing rate > 90% with an intrinsic rate of <40 bpm during interrogation.Of 511 patients who underwent TAVR for severe AS, 37(7.3%) underwent PPI after a median duration of 6 (3-7) days, whereas pacemakers were implanted after a median interval of 13 (8-28) days post-SAVR in 10 of 663 patients (P < .001). Pacemaker dependency was observed in 36 (97.3%) patients during 7 days immediately post-TAVR and in 25 (64.9%) patients between 8 and 180 days post-TAVR. Pacemaker dependency occurred after 180 days in 17 (50%) patients with TAVR and in 4 (44.4%) patients with SAVR. Twelve (41.4%) patients were pacemaker-dependent after 365 days post-TAVR.Pacemaker dependency did not differ at 6 months after TAVR vs SAVR. In patients undergoing post-TAVR PPI, 58.6% were not pacemaker-dependent at 1 year after the TAVR procedure.

In silico approaches for transcatheter aortic valve replacement inspection

Introduction: Increasing applications of transcatheter aortic valve replacement (TAVR) to treat high- or medium-risk patients with aortic diseases have been proposed in recent years. Despite its increasing use, many influential factors are still to be understood. Furthermore, innovative applications of TAVR such as in bicuspid aortic valves or in low-risk patients are emerging in clinical use. Numerical analyses are increasingly used to reproduce clinical treatments. The future trends in this area are foreseen for in silico trials and personalized medicine. Areas covered: This review paper analyzes the recent years (Jan 2018 - Aug 2020) of in silico studies simulating the behavior of transcatheter aortic valves with emphasis on the addressed clinical question and the used modeling strategies. The manuscripts are firstly classified based on their clinical hypothesis. A second classification is based on the adopted modeling approach in terms of patient domain, device modeling, and inclusion or exclusion of the fluid domain. Expert opinion: The TAVR can be virtually performed in numerous vessel geometries and with different devices. This versatility allows a rapid evaluation of the feasibility of different implantation approaches for specific patients, and patient populations, resulting in faster and safer introduction or optimization of new treatments or devices.