Association between implantation depth assessed by computed tomography and new-onset conduction disturbances after transcatheter aortic valve implantation

Evaluation of Prospective ECG-Triggered CT Scan as a Practical Alternative to Standard Retrospective ECG-Gated Scan for Pre-TAVI Patients

Purpose: CT-TAVI is a critical component of pre-TAVI assessment. The conventional method, retrospective ECG-gated scan, covering a complete cardiac cycle, measures the annulus during optimal systolic phases. Recently, prospective ECG-triggered scans acquiring images at a specific interval of the cardiac cycle were evaluated, allowing faster acquisition and lower contrast doses. Moreover, these scans might be beneficial for elderly patients, reducing the need for breath-holding and easing cooperation requirements. Still, their impact on annular measurement and procedural success has yet to be fully evaluated. Methods: This retrospective, single-center study included 419 patients who underwent CT-TAVI scans, by either prospective or retrospective scanning methods. Baseline data and calculated surgical risk scores were collected, with propensity score matching performed, followed by univariate analysis, Cox regression, and multivariable regression analysis. Results: A total of 171 patient pairs were generated via propensity score matching, ensuring that both groups had similar distributions of age (81 ± 8 years), sex (55% males), and baseline comorbidities. The patients in the prospective ECG-triggered group were exposed to a smaller amount of contrast material (40.0 ± 12 mL vs. 70.0 ± 48 mL, p < 0.001) and radiation (4.4 ± 3.6 mSv vs. 8.0 ± 10.3 mSv, p < 0.001). The prospective ECG-triggered group had a smaller aortic annulus area and diameter (426.6 ± 121.0 mm2 vs. 469.1 ± 130.8 mm2, p = 0.006 and 23.3 ± 3.2 mm vs. 24.5 ± 3.6 mm, p = 0.004) but no excess paravalvular leak was observed. Multivariable analysis showed no significant differences in mortality and composite endpoints between the two groups after 23 months of follow-up. Conclusion: Prospective ECG-triggered, ultra-fast, low-dose, high-pitch scan protocol, used in selected patients offers comparable safety and clinical procedural outcomes along with time and contrast savings.

Finite Element Analysis of Evolut Transcatheter Heart Valves: Effects of Aortic Geometries and Valve Sizes on Post-TAVI Wall Stresses and Deformations

Background/Objectives: For transcatheter aortic valve implantation (TAVI) therapy, a catheter-guided crimped valve is deployed into the aortic root. Valve types such as Edwards balloon-expandable valves and Medtronic self-expandable valves come in different sizes and are chosen based on patient-specific aortic anatomy, including aortic root diameter measurement. Complications may arise due to variations in anatomical characteristics and the implantation procedure, making pre-implantation assessment important for predicting complications. Methods: Computational modeling, particularly finite element analysis (FEA), has become popular for assessing wall stresses and deformations in TAVI. In this study, a finite element model including the aorta, native leaflets, and TAVI device was used to simulate procedures and assess patient-specific wall stresses and deformations. Results: Using the Medtronic Evolut R valve, we simulated TAVI for 14 patients to analyze the effects of geometrical variations on structural stresses. Virtual TAVIs with different valve sizes were also simulated to study the influence of TAV size on stresses. Our results show that variations in aortic wall geometries and TAV sizes significantly influence wall stresses and deformations. Conclusions: Our study is one of the first comprehensive FEA investigations of aortic geometrical variations and valve sizes on post-TAVI stresses, demonstrating the non-linear relationship between aortic dimensions, TAV sizes, and wall stresses.

Material modeling and recent findings in transcatheter aortic valve implantation simulations

BACKGROUND AND OBJECTIVE

Transcatheter aortic valve implantation (TAVI) has significantly transformed the management of aortic valve (AV) diseases, presenting a minimally invasive option compared to traditional surgical valve replacement. Computational simulations of TAVI become more popular and offer a detailed investigation by employing patient-specific models. On the other hand, employing accurate material modeling procedures and applying basic modeling steps are crucial to determining reliable numerical results. Therefore, this review aims to outline the basic modeling approaches for TAVI, focusing on material modeling and geometry extraction, as well as summarizing the important findings from recent computational studies to guide future research in the field.

METHODS

This paper explains the basic steps and important points in setting up and running TAVI simulations. The material properties of the leaflets, valves, stents, and tissues utilized in TAVI simulations are provided, along with a comprehensive explanation of the geometric extraction methods employed. The differences between the finite element analysis, computational fluid dynamics, and fluid-structure interaction approaches are pointed out and the important aspects of TAVI modeling are described by elucidating the recent computational studies.

RESULTS

The results of the recent findings on TAVI simulations are summarized to demonstrate its powerful potential. It is observed that the material properties of aortic tissues and components of implanted valves should be modeled realistically to determine accurate results. For patient-specific AV geometries, incorporating calcific deposits on the leaflets is essential for ensuring the accuracy of computational findings. The results of numerical TAVI simulations indicate the significance of the selection of optimal valves and precise deployment within the appropriate anatomical position. These factors collectively contribute to the effective functionality of the implanted valve.

CONCLUSIONS

Recent studies in the literature have revealed the critical importance of patient-specific modeling, the selection of accurate material models, and bio-prosthetic valve diameters. Additionally, these studies emphasize the necessity of precise positioning of bio-prosthetic valves to achieve optimal performance in TAVI, characterized by an increased effective orifice area and minimal paravalvular leakage.

Mitral complex geometric changes aggravate mitral stenosis after transcatheter aortic valve replacement

Severe aortic valve stenosis (AS) often coexists with mitral valve stenosis (MS). MS aggravation after transcatheter aortic valve replacement (TAVR) is common, and its etiology is multifactorial. We hypothesized that geometric changes in the mitral complex (mitral valvular and annular deformities) are adjunctive factors aggravating MS after TAVR, particularly in older adults with a smaller left ventricle (LV). This study aimed to evaluate the mitral complex geometric changes before and after TAVR and to assess the important predictors of MS aggravation after TAVR. This retrospective study enrolled consecutive adult patients who underwent TAVR and surgical AVR (SAVR) for severe AS. The mitral valve area (MVA), the angle between the anterior mitral valve leaflet (AMVL) and left ventricular outflow tract (LVOT), AMVL length, mitral annular diameter, presence of mitral annular calcification, and LV size were evaluated using transthoracic echocardiography. This study included 258 patients who underwent TAVR and SAVR. MVA index decreased from 2.3 ± 0.6 cm² to 1.9 ± 0.5 cm² in the TAVR group. The angle between the AMVL and LVOT was 56.3 ± 9.7° preoperatively and increased to 67.3 ± 11.5° after TAVR. In multivariate analysis, the most important predictive factors of MS aggravation after TAVR were a smaller mitral annular diameter, restricted AMVL mobility, and implantation depth (odds ratio: 4.5, 5.3,3.0; 95% confidence interval: 1.6-14, 1.9-17, 1.0-8.9; and p = 0.005, p = 0.001, p = 0.042, respectively). The reduction in MVA after TAVR was related to the restriction of AMVL opening, depth of implantation and narrowing of the mitral annulus.

Predictors, clinical impact, and management strategies for conduction abnormalities after transcatheter aortic valve replacement: an updated review

Transcatheter aortic valve replacement (TAVR) has increasingly become a safe, feasible, and widely accepted alternative surgical treatment for patients with severe symptomatic aortic stenosis. However, the incidence of conduction abnormalities associated with TAVR, including left bundle branch block (LBBB) and high-degree atrioventricular block (HAVB), remains high and is often correlated with risk factors such as the severity of valvular calcification, preexisting conditions in patients, and procedural factors. The existing research results on the impact of post-TAVR conduction abnormalities and permanent pacemaker (PPM) requirements on prognosis, including all-cause mortality and rehospitalization, remain contradictory, with varied management strategies for post-TAVR conduction system diseases across different institutions. This review integrates the latest research in the field, offering a comprehensive discussion of the mechanisms, risk factors, consequences, and management of post-TAVR conduction abnormalities. This study provides insights into optimizing patient prognosis and explores the potential of novel strategies, such as conduction system pacing, to minimize the risk of adverse clinical outcomes.

Latest Developments in Adapting Deep Learning for Assessing TAVR Procedures and Outcomes

Aortic valve defects are among the most prevalent clinical conditions. A severely damaged or non-functioning aortic valve is commonly replaced with a bioprosthetic heart valve (BHV) via the transcatheter aortic valve replacement (TAVR) procedure. Accurate pre-operative planning is crucial for a successful TAVR outcome. Assessment of computational fluid dynamics (CFD), finite element analysis (FEA), and fluid-solid interaction (FSI) analysis offer a solution that has been increasingly utilized to evaluate BHV mechanics and dynamics. However, the high computational costs and the complex operation of computational modeling hinder its application. Recent advancements in the deep learning (DL) domain can offer a real-time surrogate that can render hemodynamic parameters in a few seconds, thus guiding clinicians to select the optimal treatment option. Herein, we provide a comprehensive review of classical computational modeling approaches, medical imaging, and DL approaches for planning and outcome assessment of TAVR. Particularly, we focus on DL approaches in previous studies, highlighting the utilized datasets, deployed DL models, and achieved results. We emphasize the critical challenges and recommend several future directions for innovative researchers to tackle. Finally, an end-to-end smart DL framework is outlined for real-time assessment and recommendation of the best BHV design for TAVR. Ultimately, deploying such a framework in future studies will support clinicians in minimizing risks during TAVR therapy planning and will help in improving patient care.

Impact of the Aortic Geometry on TAVI Prosthesis Positioning Using Self-Expanding Valves

BACKGROUND

The impact of transcatheter heart valve (THV) position on the occurrence of paravalvular leakage and permanent pacemaker implantation caused by new-onset conduction disturbances is well described. The purpose of this study was to investigate the influence of the geometry of the thoracic aorta on the implantation depth after TAVI (transcatheter heart valve implantation) using self-expanding valve (SEV) types.

METHODS

We evaluated three-dimensional geometry of the thoracic aorta based on computed tomography angiography (CTA) in 104 subsequently patients receiving TAVI with SEV devices (Evolut R). Prosthesis position was determined using the fusion imaging method of pre- and post-procedural CTA. An implantation depth of ≥4 mm was defined as the cut-off value for low prosthesis position.

RESULTS

The mean implantation depth of the THV in the whole cohort was 4.3 ± 3.0 mm below annulus plane. THV position was low in 66 (63.5%) patients and high in 38 (36.5%) patients. After multivariate adjustment none of the aortic geometry characteristics showed an independent influence on the prosthesis position-neither the Sinus of Valsalva area (p = 0.335) nor the proximal aortic arch diameter (p = 0.754) or the distance from annulus to descending aorta (p = 0.309).

CONCLUSION

The geometry of the thoracic aorta showed no influence on the positioning of self-expanding TAVI valve types.

Patients With Bicuspid Aortic Stenosis Undergoing Transcatheter Aortic Valve Replacement: A Systematic Review and Meta-Analysis

Objective

We sought to conduct a systematic review and meta-analysis of clinical adverse events in patients undergoing transcatheter aortic valve replacement (TAVR) with bicuspid aortic valve (BAV) vs. tricuspid aortic valve (TAV) anatomy and the efficacy of balloon-expandable (BE) vs. self-expanding (SE) valves in the BAV population. Comparisons aforementioned will be made stratified into early- and new-generation devices. Differences of prosthetic geometry on CT between patients with BAV and TAV were presented. In addition, BAV morphological presentations in included studies were summarized.

Method

Observational studies and a randomized controlled trial of patients with BAV undergoing TAVR were included according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline.

Results

A total of 43 studies were included in the final analysis. In patients undergoing TAVR, type 1 BAV was the most common phenotype and type 2 BAV accounted for the least. Significant higher risks of conversion to surgical aortic valve replacement (SAVR), the need of a second valve, a moderate or severe paravalvular leakage (PVL), device failure, acute kidney injury (AKI), and stroke were observed in patients with BAV than in patients with TAV during hospitalization. BAV had a higher risk of new permanent pacemaker implantation (PPI) both at hospitalization and a 30-day follow-up. Risk of 1-year mortality was significantly lower in patients with BAV than that with TAV [odds ratio (OR) = 0.85, 95% CI 0.75–0.97, p = 0.01]. BE transcatheter heart valves (THVs) had higher risks of annular rupture but a lower risk of the need of a second valve and a new PPI than SE THVs. Moreover, BE THV was less expanded and more elliptical in BAV than in TAV. In general, the rates of clinical adverse events were lower in new-generation THVs than in early-generation THVs in both BAV and TAV.

Conclusions

Despite higher risks of conversion to SAVR, the need of a second valve, moderate or severe PVL, device failure, AKI, stroke, and new PPI, TAVR seems to be a viable option for selected patients with severe bicuspid aortic stenosis (AS), which demonstrated a potential benefit of 1-year survival, especially among lower surgical risk population using new-generation devices. Larger randomized studies are needed to guide patient selection and verified the durable performance of THVs in the BAV population.

Prosthesis Position after TAVI with Balloon-Expandable SAPIEN 3 in Bicuspid Aortic Valves

Background: Prior data suggest a correlation between the position of transcatheter heart valves (THV) and the occurrence of complications after transcatheter aortic valve implantation (TAVI) in patients with tricuspid aortic valves (TAV). However, data including a detailed analysis of prosthesis positioning in bicuspid aortic valves (BAV) are limited. Therefore, the purpose of this study was to investigate THV position after TAVI in BAV. Methods: We evaluated the THV position in 50 BAV and 50 TAV patients (all received the balloon-expandable Sapien 3 prosthesis) using fusion imaging of pre- and post-procedural computed tomography angiography. According to the manufacturers’ recommendations, a low implantation position was defined as >30% of the prosthesis below the annulus. Results: THV position was appropriate in the majority of the patients within both groups (90.0% for BAV vs. 96.0% for TAV, p = 0.240). In BAV, we observed a more pronounced THV waist (7.4 ± 4.5% vs. 5.8 ± 3.0%, p = 0.043) and a lower average THV expansion (91.9 ± 12.2% vs. 95.5 ± 2.7% of nominal expansion, p = 0.044). Conclusions: Accurate positioning in relation to the aortic annulus of the TAVI Sapien 3 prosthesis is possible in patients with BAV with results comparable to TAV. However, there is a more pronounced prosthesis waist and a lower average THV expansion in BAV.

Computed tomography analysis of coronary ostia location following valve-in-valve transcatheter aortic valve replacement with the ACURATE neo valve: Implications for coronary access

BACKGROUND

Valve-in-valve transcatheter aortic valve replacement (ViV-TAVR) is an emerging alternative to re-do surgery. However, the challenge of coronary access (CA) following ViV-TAVR is a potential limitation as TAVR expands to younger lower-risk populations.

OBJECTIVES

Using post-implantation computed tomography (CT) scans to evaluate the geometrical relationship between coronary ostia and valve frame in patients undergoing ViV-TAVR with the ACURATE neo valve.

METHODS

Post-implant CT scans of 18 out of 20 consecutive patients treated with the ACURATE neo valve were analyzed. Coronary ostia location in relation to the highest plane (HP) (highest point of the ACURATE neo or surgical valve) was determined. Ostia located below the highest plan were further subclassified according to the gap available between the transcatheter heart valve frame and ostium (transcatheter-to-coronary [TTC] distance). The impact implantation depth has on these geometrical relationships was evaluated.

RESULTS

A total of 21 out of 36 coronary ostia (58%) were located below the level of the HP with the left coronary artery (36%) more likely to be affected than the right (22%). Further sub-classification of these ostia revealed a large (>6 mm), moderate (4-6 mm), and small (<4 mm) TTC distance in 57% (12/21), 38% (8/21), and in 6% (1/18) of cases, respectively. At an implantation depth <4 mm compared to >4 mm, all ostia were located below the HP with no difference in post-procedural mean gradients (14.5 mmHg ± 4.7 vs. 12.6 mmHg ± 5.8; p = .5, 95%CI 3.8-7.5).

CONCLUSIONS

CA following ACURATE neo implantation for ViV-TAVR could potentially be challenging in a significant proportion of patients and specific consideration should be given to the implantation depth.

Fusion imaging of pre- and post-procedural computed tomography angiography in transcatheter aortic valve implantation patients: evaluation of prosthesis position and its influence on new conduction disturbances

AIMS

The purpose of this study was to evaluate prosthesis position by fusion of pre- and post-transcatheter aortic valve implantation (TAVI) computed tomography angiography (CTA) images and to investigate its influence on the occurrence of new conduction disturbances (CD).

METHODS AND RESULTS

We performed CTA fusion imaging in 120 TAVI patients (Edwards Sapien 3) on a standard image post-processing workstation to obtain a 3D reconstruction of the transcatheter heart valve (THV) position within the native annulus region. Optimal implantation depth of the THV was defined according to the manufacturers recommendations as 70-80% of the prosthesis above (aortic) and 20-30% below (ventricular) the native annulus plane. Pre- and post-interventional electrocardiograms (ECGs) were assessed for the development of new CD. THV position was found to be within, above, or below the prespecified margins in 32 patients (27%), 71 patients (59%), and 17 patients (14%), respectively. Interobserver reliability was high for fusion measurements [e.g. median THV position 0.983, 95% confidence interval (CI): 0.935-0.996]. Patients with low stent position were significantly more likely to develop new CD compared with patients with optimal or high stent position (P = 0.039). Independent predictors of CD in multivariate analysis were low THV position [odds ratio (CI): 1.362 (1.093-1.698), P = 0.006] and calcification of the device landing zone [odds ratio (CI): 1.149 (1.024-1.289), P = 0.018].

CONCLUSION

Fusion imaging of pre- and post-TAVI-CTA allows for the exact evaluation of THV position in relation to the native annulus plane. A low THV position as assessed by fusion imaging is associated with the development of new CD post-TAVI.

3D printed patient-specific aortic root models with internal sensors for minimally invasive applications

Minimally invasive surgeries have numerous advantages, yet complications may arise from limited knowledge about the anatomical site targeted for the delivery of therapy. Transcatheter aortic valve replacement (TAVR) is a minimally invasive procedure for treating aortic stenosis. Here, we demonstrate multimaterial three-dimensional printing of patient-specific soft aortic root models with internally integrated electronic sensor arrays that can augment testing for TAVR preprocedural planning. We evaluated the efficacies of the models by comparing their geometric fidelities with postoperative data from patients, as well as their in vitro hemodynamic performances in cases with and without leaflet calcifications. Furthermore, we demonstrated that internal sensor arrays can facilitate the optimization of bioprosthetic valve selections and in vitro placements via mapping of the pressures applied on the critical regions of the aortic anatomies. These models may pave exciting avenues for mitigating the risks of postoperative complications and facilitating the development of next-generation medical devices.

Intraventricular Conduction Disturbances After Transcatheter Aortic Valve Implantation

Despite significant improvements in transcatheter aortic valve implantation (TAVI) outcomes, periprocedural conduction disturbances, such as new-onset left bundle branch block (LBBB) and new pacemaker implantation (PMI), remain relatively frequent concerns. The development of periprocedural conduction disturbances can be explained by the proximity between the aortic valve and the conduction system. Although prior studies reported heterogeneity in PMI rates after TAVI, current evidence supports the potentially deleterious consequence of LBBB and PMI, and several predisposing factors have been reported. Therefore, new strategies to avoid conduction disturbances and to improve their management are required, particularly with the current trend to expand TAVI to a low-risk population.

Impact of postprocedural permanent pacemaker implantation on clinical outcomes after transcatheter aortic valve replacement: a systematic review and meta-analysis

Background

The incidence of conduction disturbances requiring permanent pacemaker (PPM) implantation following transcatheter aortic valve replacement (TAVR) have remained a common concern. The purpose of this study was to evaluate the impact of postprocedural PPM implantation following TAVR on clinical outcomes.

Methods

We performed a systematic search in PubMed and EMBASE databases for studies that reported raw data on clinical outcomes of patients with and without PPM implantation after TAVR and followed up patients for 10 months or longer. The primary endpoint was all-cause death. The secondary endpoints were cardiovascular death, heart failure and a composite of stroke and myocardial infarction (MI).

Results

Data from 20 studies with a total of 21,666 patients undergoing TAVR, of whom 12.5% required PPM implantation after intervention, were analysed and the mean duration follow-up was 16.9 months. The rate of PPM ranged from 6.2% to 32.8% among different studies. A total of 6,753 (31.2%) patients underwent TAVR with self-expandable prosthesis and 14,913 (68.8%) with balloon-expandable prosthesis. The incidence of postprocedural PPM implantation was higher with the self-expandable prosthesis (n=1,717, 25.4%) compared with the balloon-expandable prosthesis (n=996, 6.7%). PPM after TAVR was associated with a higher risk of all-cause death (RR: 1.13; 95% CI: 1.01-1.25; P=0.03) but not incidence of stroke and MI (RR: 0.85; 95% CI: 0.64-1.13; P=0.27).

Conclusions

In patients undergoing TAVR, the PPM implantation after intervention was associated higher all-cause mortality but not cardiovascular mortality, heart failure and stroke or MI, which remain an unsolved issue of TAVR.

[Transcatheter aortic valve implantation and conduction disturbances]

Transcatheter aortic valve implantation (TAVI) is currently becoming the treatment of choice for patients with calcific aortic stenosis. Despite several technical improvements, the incidence of conduction disturbances has not diminished and remains TAVI's major complication. These disturbances include the occurrence of left bundle branch block and/or high-grade atrioventricular block often requiring pacemaker implantation. The proximity of the aortic valve to the conduction system (conduction pathways) accounts for the occurrence of these complications. Several factors have been identified as carrying a high risk of conduction disturbances like the presence of pre-existing right bundle branch block, the type of valve implanted, the volume of aortic and mitral calcifications, the size of the annulus and the depth of valve implantation. Left bundle branch block is the most frequent post TAVI conduction disturbance. Whereas the therapeutic strategy for persistent complete atrioventricular block is simple, it becomes complex in the presence of fluctuating changes in PR interval and left bundle branch block duration. The QRS width threshold value (150-160 ms) indicative of the need for pacemaker implantation is still being debated. Although there are currently no recommendations regarding the management of these conduction disturbances, the extension of TAVI indications to patient at low surgical risk calls for a standardization of our practice. However, a decision algorithm was recently proposed by a group of experts composed of interventional cardiologists, electrophysiologists and cardiac surgeons. There are still uncertainties about the appropriate timing of pacemaker implantation and the management of new onset left bundle branch block.

The Impact of Size and Position of a Mechanical Expandable Transcatheter Aortic Valve: Novel Insights Through Computational Modelling and Simulation

Transcatheter aortic valve implantation has become an established procedure to treat severe aortic stenosis. Correct device sizing/positioning is crucial for optimal outcome. Lotus valve sizing is based upon multiple aortic root dimensions. Hence, it often occurs that two valve sizes can be selected. In this study, patient-specific computer simulation is adopted to evaluate the influence of Lotus size/position on paravalvular aortic regurgitation (AR) and conduction abnormalities, in patients with equivocal aortic root dimensions. First, simulation was performed in 62 patients to validate the model in terms of predicted AR and conduction abnormalities using postoperative echocardiographic, angiographic and ECG-based data. Then, two Lotus sizes were simulated at two positions in patients with equivocal aortic root dimensions. Large valve size and deep position were associated with higher contact pressure, while only large size, not position, significantly reduced the predicted AR. Despite general trends, simulations revealed that optimal device size/position is patient-specific.