Patient-Specific Computer Simulation in TAVR With the Self-Expanding Evolut R Valve

CT-Derived Patient-Specific Computer Simulation of the Novel Self-Expanding Evolut FX Implantation: A Case Series

Background/Objectives: Paravalvular leak and permanent pacemaker implantation remain relevant issues after transcatheter aortic valve implantation (TAVI). Novel device development as well as adequate preprocedural device selection can contribute to optimal outcomes. Methods: Computed tomography-based patient-specific computer anatomical analysis and simulation were used in addition to standard preprocedural preparation in three of the first Evolut FX cases in our center. Procedural and follow-up echocardiographic outcomes are presented. Results: Computed tomography-based computer simulation of Evolut FX resulted in implantation of a different size in one of three cases. In three cases of severe aortic valve stenosis, procedural as well as follow-up outcomes were satisfactory and in line with the simulated results of the chosen strategy. Conclusions: Preprocedural patient-specific computer simulation predicts and guides decision-making in TAVI with the Evolut FX platform. The combination of advanced preprocedural technology and novel technologies continues to contribute to the optimization of TAVI outcomes.

Evolving capabilities of computed tomography imaging for transcatheter valvular heart interventions - new opportunities for precision medicine

The last decade has witnessed a substantial growth in percutaneous treatment options for heart valve disease. The development in these innovative therapies has been mirrored by advances in multi-detector computed tomography (MDCT). MDCT plays a central role in obtaining detailed pre-procedural anatomical information, helping to inform clinical decisions surrounding procedural planning, improve clinical outcomes and prevent potential complications. Improvements in MDCT image acquisition and processing techniques have led to increased application of advanced analytics in routine clinical care. Workflow implementation of patient-specific computational modeling, fluid dynamics, 3D printing, extended reality, extracellular volume mapping and artificial intelligence are shaping the landscape for delivering patient-specific care. This review will provide an insight of key innovations in the field of MDCT for planning transcatheter heart valve interventions.

Cardiovascular care with digital twin technology in the era of generative artificial intelligence

Digital twins, which are in silico replications of an individual and its environment, have advanced clinical decision-making and prognostication in cardiovascular medicine. The technology enables personalized simulations of clinical scenarios, prediction of disease risk, and strategies for clinical trial augmentation. Current applications of cardiovascular digital twins have integrated multi-modal data into mechanistic and statistical models to build physiologically accurate cardiac replicas to enhance disease phenotyping, enrich diagnostic workflows, and optimize procedural planning. Digital twin technology is rapidly evolving in the setting of newly available data modalities and advances in generative artificial intelligence, enabling dynamic and comprehensive simulations unique to an individual. These twins fuse physiologic, environmental, and healthcare data into machine learning and generative models to build real-time patient predictions that can model interactions with the clinical environment to accelerate personalized patient care. This review summarizes digital twins in cardiovascular medicine and their potential future applications by incorporating new personalized data modalities. It examines the technical advances in deep learning and generative artificial intelligence that broaden the scope and predictive power of digital twins. Finally, it highlights the individual and societal challenges as well as ethical considerations that are essential to realizing the future vision of incorporating cardiology digital twins into personalized cardiovascular care.

Conduction Abnormalities after Transcatheter Aortic Valve Implantation: Incidence, Impact and Management Using CT Data Interpretation

The demonstrated safety and effectiveness of transcatheter aortic valve implantation (TAVI) among low surgical risk patients opened the road to its application in younger low-risk patients. However, the occurrence of conduction abnormalities and need for permanent pacemaker implantation remains a frequent problem associated with adverse outcomes. The clinical implications may become greater when TAVI shifts towards younger populations, highlighting the need for comprehensive strategies to address this issue. Beyond currently available clinical and electrocardiographic predictors, patient-specific anatomical assessment of the aortic root using multi-sliced CT (MSCT) imaging can refine risk stratification. Moreover, leveraging MSCT data for computational 3D simulations to predict device-anatomy interactions may help guide procedural strategy to mitigate conduction abnormalities. The aims of this review are to summarise the incidence and clinical impact of new left bundle branch block and permanent pacemaker implantation post-TAVI using contemporary transcatheter heart valves; and highlight the value of MSCT data interpretation to improve the management of this complication.

In vitro bench testing using patient-specific 3D models for percutaneous pulmonary valve implantation with Venus P-valve

BACKGROUND

Due to the wide variety of morphology, size, and dynamics, selecting an optimal valve size and location poses great difficulty in percutaneous pulmonary valve implantation (PPVI). This study aimed to report our experience with in vitro bench testing using patient-specific three-dimensional (3D)-printed models for planning PPVI with the Venus P-valve.

METHODS

Patient-specific 3D soft models were generated using PolyJet printing with a compliant synthetic material in 15 patients scheduled to undergo PPVI between July 2018 and July 2020 in Central China Fuwai Hospital of Zhengzhou University.

RESULTS

3D model bench testing altered treatment strategy in all patients (100%). One patient was referred for surgery because testing revealed that even the largest Venus P-valve would not anchor properly. In the remaining 14 patients, valve size and/or implantation location was altered to avoid valve migration and/or compression coronary artery. In four patients, it was decided to change the point anchoring because of inverted cone-shaped right ventricular outflow tract (RVOT) ( n = 2) or risk of compression coronary artery ( n = 2). Concerning sizing, we found that an oversize of 2-5 mm suffices. Anchoring of the valve was dictated by the flaring of the in- and outflow portion in the pulmonary artery. PPVI was successful in all 14 patients (absence of valve migration, no coronary compression, and none-to-mild residual pulmonary regurgitation [PR]). The diameter of the Venus P-valve in the 3D simulation group was significantly smaller than that of the conventional planning group (36 [2] vs. 32 [4], Z = -3.77, P <0.001).

CONCLUSIONS

In vitro testing indicated no need to oversize the Venus P-valve to the degree recommended by the balloon-sizing technique, as 2-5 mm sufficed.

Preoperative computed tomography-imaging with patient-specific computer simulation in transcatheter aortic valve implantation: Design and rationale of the GUIDE-TAVI trial

BACKGROUND

Transcatheter aortic valve implantation (TAVI) is an established treatment option for patients with severe aortic valve stenosis, but is still associated with relatively high rates of pacemaker implantation and paravalvular regurgitation. Routine preoperative computed tomography (CT) combined with patient-specific computer modelling can predict the interaction between the TAVI device and the patient's unique anatomy, allowing physicians to assess the risk for paravalvular regurgitation and conduction disorders in advance to the procedure. The aim of this trial is to assess potential improvement in the procedural outcome of TAVI by applying CT-based patient-specific computer simulations in patients with suitable anatomy for TAVI.

METHODS

The GUIDE-TAVI trial is an international multicenter randomized controlled trial including patients accepted for TAVI by the Heart Team. Patients enrolled in the study will be randomized into 2 arms of each 227 patients. In patients randomized to the use of FEops HEARTGuide (FHG), patient-specific computer simulation with FHG is performed in addition to routine preoperative CT imaging and results of the FHG are available to the operator(s) prior to the scheduled intervention. In patients randomized to no use of FHG, only routine preoperative CT imaging is performed. The primary objective is to evaluate whether the use of FHG will reduce the incidence of mild to severe PVR, according to the Valve Academic Research Consortium 3. Secondary endpoints include the incidence of new conduction disorders requiring permanent pacemaker implantation, the difference between preoperative and final selected valve size, the difference between target and final implantation depth, change of preoperative decision, failure to implant valve, early safety composite endpoint and quality of life.

CONCLUSIONS

The GUIDE-TAVI trial is the first multicenter randomized controlled trial to evaluate the value of 3-dimensional computer simulations in addition to standard preprocedural planning in TAVI procedures.

Artificial Intelligence, Computational Simulations, and Extended Reality in Cardiovascular Interventions

Artificial intelligence, computational simulations, and extended reality, among other 21st century computational technologies, are changing the health care system. To collectively highlight the most recent advances and benefits of artificial intelligence, computational simulations, and extended reality in cardiovascular therapies, we coined the abbreviation AISER. The review particularly focuses on the following applications of AISER: 1) preprocedural planning and clinical decision making; 2) virtual clinical trials, and cardiovascular device research, development, and regulatory approval; and 3) education and training of interventional health care professionals and medical technology innovators. We also discuss the obstacles and constraints associated with the application of AISER technologies, as well as the proposed solutions. Interventional health care professionals, computer scientists, biomedical engineers, experts in bioinformatics and visualization, the device industry, ethics committees, and regulatory agencies are expected to streamline the use of AISER technologies in cardiovascular interventions and medicine in general.

A review of numerical simulation in transcatheter aortic valve replacement decision optimization

BACKGROUND

Recent trials indicated a further expansion of clinical indication of transcatheter aortic valve replacement to younger and low-risk patients. Factors related to longer-term complications are becoming more important for use in these patients. Accumulating evidence indicates that numerical simulation plays a significant role in improving the outcome of transcatheter aortic valve replacement. Understanding mechanical features' magnitude, pattern, and duration is a topic of ongoing relevance.

METHODS

We searched the PubMed database using keywords such as "transcatheter aortic valve replacement" and "numerical simulation" and reviewed and summarized relevant literature.

FINDINGS

This review integrated recently published evidence into three subtopics: 1) prediction of transcatheter aortic valve replacement outcomes through numerical simulation, 2) implications for surgeons, and 3) trends in transcatheter aortic valve replacement numerical simulation.

INTERPRETATIONS

Our study offers a comprehensive overview of the utilization of numerical simulation in the context of transcatheter aortic valve replacement, and highlights the advantages, potential challenges from a clinical standpoint. The convergence of medicine and engineering plays a pivotal role in enhancing the outcomes of transcatheter aortic valve replacement. Numerical simulation has provided evidence of potential utility for tailored treatments.

Transcatheter valvular therapies in patients with left ventricular assist devices

Aortic, mitral and tricuspid valve regurgitation are commonly encountered in patients with continuous-flow left ventricular assist devices (CF-LVADs). These valvular heart conditions either develop prior to CF-LVAD implantation or are induced by the pump itself. They can all have significant detrimental effects on patients' survival and quality of life. With the improved durability of CF-LVADs and the overall rise in their volume of implants, an increasing number of patients will likely require a valvular heart intervention at some point during CF-LVAD therapy. However, these patients are often considered poor reoperative candidates. In this context, percutaneous approaches have emerged as an attractive "off-label" option for this patient population. Recent data show promising results, with high device success rates and rapid symptomatic improvements. However, the occurrence of distinct complications such as device migration, valve thrombosis or hemolysis remain of concern. In this review, we will present the pathophysiology of valvular heart disease in the setting of CF-LVAD support to help us understand the underlying rationale of these potential complications. We will then outline the current recommendations for the management of valvular heart disease in patients with CF-LVAD and discuss their limitations. Lastly, we will summarize the evidence related to transcatheter heart valve interventions in this patient population.

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.

[Contribution of CT-scan fusion imaging for interventional cardiology]

Fusion imaging is developing fast, allowing improvements in interventional cardiology procedures workup and guidance. Computed-tomography (CT) scan and fluoroscopy fusion guidance used in procedures such as left appendage occlusion or perivalvular leak closure permit prediction and simulation of the appropriatedevice, as well as implantation guidance. In the era of tailored medicine, CT/fluoroscopy fusion imaging guidance is an interesting tool for individualizing and adapting the devices implanted to each patient, as well as improving the outcomes and safety of each procedure.

A 20-year journey in transcatheter aortic valve implantation: Evolution to current eminence

Since the first groundbreaking procedure in 2002, transcatheter aortic valve implantation (TAVI) has revolutionized the management of aortic stenosis (AS). Through striking developments in pertinent equipment and techniques, TAVI has now become the leading therapeutic strategy for aortic valve replacement in patients with severe symptomatic AS. The procedure streamlining from routine use of conscious sedation to a single arterial access approach, the newly adapted implantation techniques, and the introduction of novel technologies such as intravascular lithotripsy and the refinement of valve-bioprosthesis devices along with the accumulating experience have resulted in a dramatic reduction of complications and have improved associated outcomes that are now considered comparable or even superior to surgical aortic valve replacement (SAVR). These advances have opened the road to the use of TAVI in younger and lower-risk patients and up-to-date data from landmark studies have now established the outstanding efficacy and safety of TAVI in patients with low-surgical risk impelling the most recent ESC guidelines to propose TAVI, as the main therapeutic strategy for patients with AS aged 75 years or older. In this article, we aim to summarize the most recent advances and the current clinical aspects involving the use of TAVI, and we also attempt to highlight impending concerns that need to be further addressed.

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.

Biomechanics of Transcatheter Aortic Valve Replacement Complications and Computational Predictive Modeling

Transcatheter aortic valve replacement (TAVR) is a rapidly growing field enabling replacement of diseased aortic valves without the need for open heart surgery. However, due to the nature of the procedure and nonremoval of the diseased tissue, there are rates of complications ranging from tissue rupture and coronary obstruction to paravalvular leak, valve thrombosis, and permanent pacemaker implantation. In recent years, computational modeling has shown a great deal of promise in its capabilities to understand the biomechanical implications of TAVR as well as help preoperatively predict risks inherent to device-patient-specific anatomy biomechanical interaction. This includes intricate replication of stent and leaflet designs and tested and validated simulated deployments with structural and fluid mechanical simulations. This review outlines current biomechanical understanding of device-related complications from TAVR and related predictive strategies using computational modeling. An outlook on future modeling strategies highlighting reduced order modeling which could significantly reduce the high time and cost that are required for computational prediction of TAVR outcomes is presented in this review paper. A summary of current commercial/in-development software is presented in the final section.

Patient-specific computer simulation to predict long-term outcomes after transcatheter aortic valve replacement

BACKGROUND

Patient-specific computer simulation may predict the development of paravalvular regurgitation (PVR) after transcatheter aortic valve replacement (TAVR). We hypothesised that patient-specific computer simulation might identify patients at risk for long-term adverse outcomes after TAVR.

METHODS

A multi-centre retrospective study was performed on patients with symptomatic severe aortic stenosis who had undergone TAVR with a self-expanding transcatheter heart valve (THV). Pre-procedural cardiac computed tomography imaging was used to create finite element models of the aortic root. Finite element analysis (FEA) was performed in order to simulate the interaction between the THV and the native anatomy. The blood domain was extracted from the FEA output and computational fluid dynamics (CFD) simulation undertaken. Predicted PVR was recorded in the left ventricular outflow tract. Patients were classified into those where computer simulation predicted no significant PVR (predicted PVR from CFD <16.0 ​mL/s) and those where computer simulation predicted significant PVR (predicted PVR from CFD ≥16.0 ​mL/s).

RESULTS

A total of 203 patients were included in the study. THVs implanted were CoreValve (n ​= ​20), Evolut R (n ​= ​90) and Evolut PRO (n ​= ​93). At 2 years, the Kaplan-Meier estimate of the rate of death from any cause was higher in the group where CFD simulation predicted significant PVR (35.8% vs. 16.3%; hazard ratio, 2.62; 95% confidence interval, 1.29 to 5.30; P ​= ​0.006 by log-rank test).

CONCLUSIONS

Computer simulation may identify patients who are at a higher risk for death after TAVR.

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.

Advancements in Transcatheter Aortic Valve Implantation: A Focused Update

Transcatheter aortic valve implantation (TAVI) has become the leading technique for aortic valve replacement in symptomatic patients with severe aortic stenosis with conventional surgical aortic valve replacement (SAVR) now limited to patients younger than 65-75 years due to a combination of unsuitable anatomies (calcified raphae in bicuspid valves, coexistent aneurysm of the ascending aorta) and concerns on the absence of long-term data on TAVI durability. This incredible rise is linked to technological evolutions combined with increased operator experience, which led to procedural refinements and, accordingly, to better outcomes. The article describes the main and newest technical improvements, allowing an extension of the indications (valve-in-valve procedures, intravascular lithotripsy for severely calcified iliac vessels), and a reduction of complications (stroke, pacemaker implantation, aortic regurgitation).

Patient-specific Computer Simulation: An Emerging Technology for Guiding the Transcatheter Treatment of Patients with Bicuspid Aortic Valve

Transcatheter aortic valve implantation (TAVI) is increasingly being used to treat younger, lower-risk patients, many of whom have bicuspid aortic valve (BAV). As TAVI begins to enter these younger patient cohorts, it is critical that clinical outcomes from TAVI in BAV are matched to those achieved by surgery. Therefore, the identification of patients who, on an anatomical basis, may not be suitable for TAVI, would be desirable. Furthermore, clinical outcomes of TAVI in BAV might be improved through improved transcatheter heart valve sizing and positioning. One potential solution to these challenges is patient-specific computer simulation. This review presents the methodology and clinical evidence surrounding patient-specific computer simulation of TAVI in BAV.

Artificial Intelligence and Transcatheter Interventions for Structural Heart Disease: A glance at the (near) future

With innovations in therapeutic technologies and changes in population demographics, transcatheter interventions for structural heart disease have become the preferred treatment and will keep growing. Yet, a thorough clinical selection and efficient pathway from diagnosis to treatment and follow-up are mandatory. In this review we reflect on how artificial intelligence may help to improve patient selection, pre-procedural planning, procedure execution and follow-up so to establish efficient and high quality health care in an increasing number of patients.