TAVI Device Research Articles

Compliant Aortic Annulus Sizing With Different Elliptical Ratios Through a Valvuloplasty Balloon Catheter.

Aortic stenos (AS) is a heart valve disease that commonly affects the elderly. Transcatheter aortic valve implantation is a minimally invasive treatment that allows to replace the function of the diseased native valve with a prosthetic device, relying on catheters for device implantation. According to the current clinical guidelines, the choice of the implanted device is based on preoperative sizing determined by image-based technology. However, this assessment faces inherent limitations that can lead to sub-optimal sizing of the prosthesis; in turn, this can cause major post-operative complications like aortic regurgitation or cardiac electrical signal disruption. By utilizing balloon pressure and volume data, this article proposes an intra-operative method for determining the dimension of the aortic annulus which takes into account its compliance and geometric irregularity. The intra-balloon pressure-volume curves were obtained using an Automated Balloon Inflation Device operating a commercially available valvuloplasty balloon catheter. A sizing algorithm to estimate the dimensions of the annulus was integrated via a validated analytical model and a numerical model for balloon free-inflation. Tests were performed on circular and elliptical idealised aortic phantoms. Experimental results confirm that the pressure-volume data processed with the sizing algorithm can be used to determine the circular annular diameter for all tissue rigidities. The measurement of stiffer elliptical annulus phantoms shows good accuracy and high repeatability. This work represents substantial progress toward improving the selection of TAVI devices by using balloon catheters to improve the sizing of compliant aortic annuli with complex geometry.

Using artificial intelligence for device identification and characterization in angiographic sequences of TAVI procedures as radiomic biomarkers for prosthesis deterioration

Abstract Introduction Transcatheter Aortic Valve Implantation (TAVI) has been established as the preferential option for patients suffering from symptomatic severe aortic stenosis with high surgical risk. Due to the implantation of prosthesis on younger patients, the durability of TAVI devices becomes a crucial issue, especially beyond 5 years of follow-up [1]. Therefore, an application of growing interest is the assessment of the prosthesis deterioration, which is directly related to the measurement of the stent tip deflection [2]. In order to extract this parameter from angiographic sequences, a prior requirement relies on the automatic detection of the prosthesis in the image, pointing directly to the use of Artificial Intelligence. Purpose Automatically segment TAVI prostheses in angiographic sequences using Deep Learning [3]. The aim is allowing the extraction of information from these images, as the measurement of the stent tip deflection for evaluating the prosthesis deterioration, to improve the clinical practice. Methods A U-Net, which is a Deep Learning architecture designed for the analysis of biomedical imaging, has been trained for the segmentation of TAVI prostheses in angiographies [3]. The self-built dataset includes 50 sequences captured during TAVI from a population of 15 patients, obtaining 2827 frames (examples provided in Fig. 1). This dataset is randomly split into training and test sets using an 80/20 ratio. The U-Net is trained using the training set and its annotations (manually generated), optimised during 50 epochs using Adam optimiser, and binary cross-entropy as the cost function. Once the model has been trained, it is used for the segmentation of the images in the test set. Results The segmentation results have been evaluated in separate subsets of frames extracted from the test set, regarding the stage of the procedure they correspond. Such subsets are aortic root previous to the device delivery (Fig. 1A), prosthesis deployment (Fig. 1B), prosthesis fully-expanded (Fig. 1C), and contrast agent injection (Fig. 1D). Fig. 2 provides examples of the results obtained for the images in Fig. 1, showing the original frames and the segmentation result overlaid. The results have been evaluated in terms of different classification metrics, obtaining the mean values in the following ranges for the four groups: accuracy 0.99–1.00, recall 0.70–0.97, and area under the receiver operating characteristic curve (AUROC) 0.85–0.98. Conclusion U-Net has been successfully applied to angiographic imaging captured during TAVI procedure for segmenting the prosthesis, with AUROC values between 0.85 and 0.98. The prosthesis identification and characterization allow the extraction of imaging biomarkers of great interest that can be used for the evaluation of the prosthesis deterioration. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Axencia Galega de Innovaciόn (GAIN) (Code Numbers IN845D-2020/29 and IN607B-2021/18)

Using artificial intelligence for device identification and characterization in angiographic sequences of TAVI procedures as radiomic biomarkers for prosthesis deterioration

Abstract Introduction Transcatheter Aortic Valve Implantation (TAVI) has been established as the preferential option for patients suffering from symptomatic severe aortic stenosis with high surgical risk. Due to the implantation of prosthesis on younger patients, the durability of TAVI devices becomes a crucial issue, especially beyond 5 years of follow-up [1]. Therefore, an application of growing interest is the assessment of the prosthesis deterioration, which is directly related to the measurement of the stent tip deflection [2]. In order to extract this parameter from angiographic sequences, a prior requirement relies on the automatic detection of the prosthesis in the image, pointing directly to the use of Artificial Intelligence. Purpose Automatically segment TAVI prostheses in angiographic sequences using Deep Learning [3]. The aim is allowing the extraction of information from these images, as the measurement of the stent tip deflection for evaluating the prosthesis deterioration, to improve the clinical practice. Methods A U-Net, which is a Deep Learning architecture designed for the analysis of biomedical imaging, has been trained for the segmentation of TAVI prostheses in angiographies [3]. The self-built dataset includes 50 sequences captured during TAVI from a population of 15 patients, obtaining 2827 frames (examples provided in Fig. 1). This dataset is randomly split into training and test sets using an 80/20 ratio. The U-Net is trained using the training set and its annotations (manually generated), optimised during 50 epochs using Adam optimiser, and binary cross-entropy as the cost function. Once the model has been trained, it is used for the segmentation of the images in the test set. Results The segmentation results have been evaluated in separate subsets of frames extracted from the test set, regarding the stage of the procedure they correspond. Such subsets are aortic root previous to the device delivery (Fig. 1A), prosthesis deployment (Fig. 1B), prosthesis fully-expanded (Fig. 1C), and contrast agent injection (Fig. 1D). Fig. 2 provides examples of the results obtained for the images in Fig. 1, showing the original frames and the segmentation result overlaid. The results have been evaluated in terms of different classification metrics, obtaining the mean values in the following ranges for the four groups: accuracy 0.99–1.00, recall 0.70–0.97, and area under the receiver operating characteristic curve (AUROC) 0.85–0.98. Conclusion U-Net has been successfully applied to angiographic imaging captured during TAVI procedure for segmenting the prosthesis, with AUROC values between 0.85 and 0.98. The prosthesis identification and characterization allow the extraction of imaging biomarkers of great interest that can be used for the evaluation of the prosthesis deterioration. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Axencia Galega de Innovaciόn (GAIN) (Code Numbers IN845D-2020/29 and IN607B-2021/18)

Prosthesis-Patient Mismatch in Small Aortic Annuli: Self-Expandable vs. Balloon-Expandable Transcatheter Aortic Valve Replacement.

Prosthesis–patient mismatch (PPM) is associated with worse outcomes following surgical aortic valve replacement (SAVR). PPM has been identified in a significant proportion of TAVR, particularly in patients with small aortic annuli. Our objective was to evaluate the hemodynamic performances of balloon-expandable (BE) (Sapiens 3TM) versus two different self-expandable (SE) (Evolut ProTM, Accurate NeoTM) TAVR devices in patients with small aortic annulus defined by a computed tomography aortic annulus area (AAA) between 330 and 440 mm2. We enrolled 131 consecutive patients corresponding to 76 Sapiens 3 23 mm (58.0%), 26 Evolut Pro (19.9%) and 29 Accurate Neo (22.1%). Mean age was 82.5 ± 7.06 years, 22.9% of patients were male and mean Euroscore was 4.0%. Mean AAA was 374 ± 27 mm2 for Sapiens 3, 383 ± 29 mm2 for Corevalve Evolut Pro and 389 ± 25 mm2 for Accurate Neo. BE devices were associated with significantly higher rates of PPM (39.5%) as compared to SE devices (15.4% for Corevalve Evolut Pro and 6.9% for Accurate Neo) (p < 0.0001). Paravalvular leaks ≥ 2/4 were more often observed in SE devices (15.4% for Corevalve Evolut Pro and 17.2% for Accurate Neo) than in BE devices (2.6%) (p = 0.007). In conclusion, SE TAVR devices did achieve better hemodynamic results despite higher rates of paravalvular leaks. Therefore, SE TAVI devices could be considered as first choice in small aortic anatomy.

Magnetic retrieval of prosthetic heart valves for redo-TAVI

Bioprosthetic aortic heart valves are known to degenerate within 7–15 years of implantation. Currently, the options for treating a failing valve are (a) redo surgical aortic valve replacement or, increasingly, (b) valve-in-valve transcatheter aortic valve implantation (ViV-TAVI). The ViV-TAVI procedure is referred to as redo-TAVI when the failing valve is a TAVI device. Repeated procedures, such as two or three valve-in-valves, significantly reduce the effective valve flow area, putting a limit on recurrent treatments. With increasing life expectancy and the use of TAVI in younger, lower-risk patients, the demand for multiple replacement procedures will inevitably increase. Against this background, we describe a novel valve system named exchangeable-TAVI (e-TAVI) in which an electromagnetic catheter is used to remove and retrieve a failed exchangeable valve, followed by the immediate deployment of a new valve. The e-TAVI system comprises (i) an exchangeable valve, (ii) a permanent holding member that anchors the exchangeable valve and (iii) a dedicated catheter with electromagnets for removal of the exchangeable valve. Simulations have been performed to determine the forces, frame design and electromagnetic parameters required to crimp and retrieve a 26 mm diameter valve. An optimum configuration was found to comprise a 12 cell self-expanding frame with circular ferromagnetic regions of 1 mm radius and 0.5 mm thickness, along with eight electromagnets of 1 mm radius and 2 mm thickness. A force of 2.87 N and a current of 2.52 A per electromagnet were required to partially crimp the frame to an envelope radius of 11 mm. While this amount of force allowed the frame to be crimped solely through magnetic attraction, re-sheathing of the frame was not possible due to the weaker shear holding force of the magnets. Also, the current was close to the fusing current of the copper wire needed to fit sufficient windings into the available volume. These issues led to the conclusion that, in addition to the magnetic coupling, a mechanical mating between the removal catheter and the exchangeable valve is needed. This would decrease both the force that the electromagnets had to exert during crimping and the current required to generate this force.

Computed Tomography Features of Cuspal Thrombosis and Subvalvular Tissue Ingrowth after Transcatheter Aortic Valve Implantation

Post-transcatheter aortic valve implantation (TAVI) computed tomography (CT) findings have not been fully elucidated, except hypoattenuating leaflet thickening (HALT). The objective of this study was to describe cardiac CT findings after TAVI, and investigate factors associated with HALT. This retrospective study included patients who underwent TAVI and post-TAVI cardiac CT scans. On CT, abnormal findings such as hypoattenuating subvalvular thickening (HAST), thrombus within the sinus of Valsalva, HALT, and leaflet motion limitation were thoroughly reviewed. Clinical and CT findings were compared between patients with HALT and those without HALT. Logistic regression analysis was performed to determine factors associated with HALT. A total of 138 patients (64 male, mean 78.5±5.2 years of age) with post-TAVI CT scans were included. The median duration from TAVI to CT was 17.5 days (interquartile range, 3 to 390.8 days). HAST and thrombus within the sinus of Valsalva were detected in 32 (23%) and 5 (4%) patients, respectively. HALT and leaflet motion limitations were found in 25 (18%) and 20 (14%) of patients, respectively. Pannus was diagnosed in 2 patients. TAVI device implant duration (odds ratio [OR], 1.5; p=0.01), hypertension (OR, 0.2; p = 0.03), and HAST (OR, 4.9; p = 0.003) were associated with HALT. Implant durations were longer in patients with HAST, HALT, or leaflet motion limitation (p<0.05, for all). In conclusion, HAST, HALT, thrombus within the sinus of Valsalva, and leaflet motion limitation are not uncommon after TAVI. Implant duration, hypertension, and HAST are associated with HALT.

TCT-44 Comparative effectiveness and safety of five leading new-generation TAVI devices: 12-month results from the RISPEVA Study

TCT-44 Comparative effectiveness and safety of five leading new-generation TAVI devices: 12-month results from the RISPEVA Study

HEMODYNAMIC AND ECHOCARDIOGRAPHIC COMPARISON AT 1 YEAR OF THE LOTUS AND COREVALVE TRANSCATHETER AORTIC VALVES IN HIGH AND EXTREME SURGICAL RISK PATIENTS: AN ANALYSIS FROM THE REPRISE III RANDOMIZED CONTROLLED TRIAL

REPRISE III is a multicenter, randomized comparison of the novel mechanically-expanded (Lotus) and self-expanding (CoreValve; CV) TAVI devices. Lotus was superior for primary effectiveness and non-inferior for primary safety endpoints. A detailed analysis of the hemodynamics and paravalvular leak (

TCT-304 Impact of predilation before TAVI with five leading new-generation TAVI devices: early results from the RISPEVA Study

TCT-304 Impact of predilation before TAVI with five leading new-generation TAVI devices: early results from the RISPEVA Study

Structural valve deterioration after transcatheter aortic valve implantation

BackgroundTranscatheter aortic valve implantation (TAVI), widely used to treat high-risk patients with severe symptomatic aortic stenosis, has recently been extended to younger patients at lower operative risk in whom long-term...

The impact of imperfect frame deployment and rotational orientation on stress within the prosthetic leaflets during transcatheter aortic valve implantation

TAVI devices are manufactured with cylindrical frames. However, the frames are rarely cylindrical post-deployment since deformation due to localised under expansion can be induced by calcified material on the native valve leaflets exerting irregular forces upon the frame. Consequently, the leaflets within a deformed TAVI device may undergo elevated stress during operation, which may lead to premature device failure.Using computational analysis a complete TAVI device model was simulated undergoing deployment into an aortic root model derived from CT data for a patient with severe calcific aortic stenosis, followed by a pressure simulated cardiac cycle. The complete analysis was performed eight times, each with the device at a different rotational orientation relative to the native valve, with an increment spacing of 15°.The TAVI device frames consistently featured significant distortions associated with bulky calcified material at the base of the non-coronary sinus. It was found that the average von Mises stress in the prosthetic valves was only increased in one of the cases relative to an idealised device. However, the maximum von Mises stress in the prosthetic valves was elevated in the majority of the cases.Furthermore, it was found that there were preferable orientations to deploy the prosthetic device, in this case, when the prosthetic leaflets were aligned with the native leaflets. As device orientation deviated from this orientation, the stresses in the valve increased because the distance between the prosthetic commissures decreased. This potentially could represent a sufficient increase in stress to induce variation in device lifespan.

Patterns and trends of transcatheter aortic valve implantation in Italy: insights from RISPEVA.

Clinical trials have shown that transcatheter aortic valve implantation for aortic stenosis compares favorably to surgical replacement in high-risk patients and is superior to medical therapy in those at prohibitive risk. There is uncertainty however on patterns and trends in transcatheter aortic valve implantation, especially focusing on Italy. The RISPEVA study is a prospective Italian registry including 21 institutions. Patients have been enrolled since late 2012, and data collection includes several baseline, procedural, in-hospital, and follow-up details. For the present analysis on patterns and trends, we focused on patients enrolled between 2012 and 2015, and as primary variable on the prevalence of high versus prohibitive surgical risk, limiting our scope to procedural outcomes. A total of 1157 patients were included. The temporal breakdown was 376 (33%) patients enrolled in 2013, 408 (35%) in 2014, and 373 (32%) in 2015. Several patient features differed over time, including risk score, peripheral artery disease, end-stage pulmonary disease, and prior valvuloplasty (all P < 0.05). Several procedural features differed significantly over time, including sheath size, use of general anesthesia, Prostar closure device, predilation, antiembolic device, new TAVI device, and multiple prostheses (all P < 0.05). No significant temporal differences were found for major clinical outcomes, whereas the occurrence of moderate or severe postprocedural regurgitation and pacemaker dependency decreased over the years (both P < 0.05). According to the RISPEVA results, the Italian uptake of TAVI is steady, with evident trends toward less invasive approaches and fitter patients.

TAVI device selection: time for a patient-specific approach.

Individualised, patient-centred care is a central tenet of modern medicine. The variety of transcatheter heart valves currently available affords the opportunity to select the most appropriate device for each individual patient. Prosthesis selection should be based on operator experience and pre-procedural multimodal three-dimensional imaging. Herein, we outline a number of clinical scenarios where specific transcatheter heart valve technologies have the potential to optimise clinical outcome.

Transfemoral Rescue for a Transapical Malpositioned TAVI Device

Transfemoral Rescue for a Transapical Malpositioned TAVI Device

TCT-699 The Italian DFM Registry: real world results of a next generation fully repositionable TAVI device

The Direct Flow Medical transcatheter aortic valve system has a non-metallic design with a pressurized support structure, which allows precise positioning, retrieval and full hemodynamic assessment of valve performance prior to permanent implantation. The Direct Flow Italian registry is a nationwide

Successful treatment of failing biological prosthesis because of “Stent creep” with valve‐in‐valve transcatheter aortic valve implantation

Stent creep is an uncommon mode of structural deterioration of bioprosthetic heart valves defined by a permanent inward deflection of the stent posts. This may occur because of valve over-sizing and leads to intrinsic valve stenosis. It has been described in older generation of bioprosthesis and was thought not to occur in modern devices. We describe three patients who were referred for bioprosthetic valve degeneration with presumed aortic stenosis. Investigations demonstrated mid valvular gradient predominantly because of stent creep. We performed valve-in-valve TAVI with Edward SAPIEN prosthesis. Median age was 84 and logistic EuroSCORE 34.4. All patients had degenerated bioprosthesis with mean implant duration of 5.6 years. Two patients had Carpentier Edwards Perimount prosthesis (19 and 23 mm) and one patient had a Mitroflow (21 mm). Mean gradients were 33, 54, and 22 mm Hg. About 23 mm Edward SAPIEN valve was implanted in all cases with immediate improvement in haemodynamics with mean gradient reduction to 10, 17, and 8 mm Hg, respectively. The mean aortic valve area increased from 0.63 to 1.76cm(2) . There were no serious adverse events. The patients improved from NYHA III/IV to I/II post procedure and remain well at median follow-up of 24-months. Stent creep is an uncommon mode of structural deterioration in bioprosthetic heart valves. It has been described in the previous generation of bioprosthesis. It is important to distinguish leaflet dysfunction and stent creep. By forcing the stent posts outwards a balloon expandable TAVI device can be used to treat this condition.

Transapical transcatheter aortic valve implantation using the second-generation self-expanding Symetis ACURATE TA valve.

Transapical transcatheter aortic valve implantation (TA-TAVI) is the recognized first choice surgical TAVI access. Expansion of this well-established treatment modality with subsequent broader patient inclusion has accelerated development of second-generation TA-TAVI devices. The Swiss ACURATE TA Symetis valve allows for excellent anatomical positioning, resulting in a very low incidence of paravalvular leaks. The self-expanding stent features an hourglass shape to wedge the native aortic valve annulus. A specially designed delivery system facilitates controlled release aided by tactile operator feedback. The ACURATE TA valve made of three native porcine non-coronary leaflets has received CE approval in September 2011. Since then, this valve is the third most frequently implanted TAVI device with over 1200 implants in Europe and South America. Results from the Symetis ACURATE TA™ Valve Implantation ('SAVI') Registry showed a procedural success rate of 98.0% and a survival rate of 93.2% at 30 days. This presentation provides technical considerations and detailed procedural aspects of device implantation.

Valve-in-valve implantation of a novel and small self-expandable transcatheter heart valve in degenerated small surgical bioprostheses: the Hamburg experience.

Transcatheter valve-in-valve (VIV) implantation has emerged as a novel treatment option in patients with degenerated aortic bioprostheses and high surgical risk. However, VIV implantation in small aortic bioprostheses using first generation TAVI devices has frequently resulted in high postprocedural gradients and small effective orifice areas. Recently, an updated version of the self-expandable Medtronic CoreValve prosthesis, which is particularly suitable for small aortic annuli, has become available. We report on the feasibility and early results of VIV implantation using this novel device in a series of patients with degenerated small aortic bioprostheses. 16 patients from two Hamburg hospitals (age range 72-92 years) underwent implantation of a 23-mm CoreValve Evolut (Medtronic, Minneapolis, MN, USA) transcatheter heart valve into failing aortic bioprostheses with internal diameters below 21 mm. All patients were considered high risk for surgical aortic valve replacement after evaluation by an interdisciplinary heart team mean (logistic EuroSCORE range 9.0-88%). Implantation was successful without relevant remaining aortic regurgitation or signs of stenosis and a marked reduction in postprocedural gradientswas observed in 14 out of 16 patients. The mean gradient was reduced from from 34 mm Hg (SEM 10 mm Hg) to 14 mm Hg (SEM 6 mm Hg). No major device- or procedure-related adverse events occurred during 30-day follow up and clinical improvement was observed. Failing aortic bioprostheses with small internal diameters continue to be a challenging pathology for TAVI due to the risk of high residual gradients and small aortic orifice areas. This report provides first evidence that the 23-mm CoreValve Evolut, a novel self-expanding prosthesis, provides an improved treatment option in these specific patients due to its low profile which resulted in promising early results. © 2013 Wiley Periodicals, Inc.

MSCT guided sizing of the Edwards Sapien XT TAVI device: Impact of different degrees of oversizing on clinical outcome

Prospective data on the usage of 3-dimensional imaging based annulus sizing on the outcome of TAVI is not available yet and there is general uncertainty about the optimal degree of oversizing. In the current study we therefore assessed a 3-D MSCT guided over-sizing approach and evaluated the clinical outcome of different degrees of oversizing. TAVI-size-selection was done using systolic MSCT-annulus cross-sectional-area (CSA) measurements in 107 patients with severe aortic stenosis with the goal to oversize the 3rd generation balloon expandable Edwards Sapien XT (ESTV) device in relation to the native aortic annulus CSA. Among different degrees of oversizing there were no differences in the occurrence of stroke, myocardial infarction and death. No aortic injuries were observed. The overall rate of >mild postprocedural aortic regurgitation (PAR) was 7.6%. Increasing oversizing ratios are associated with lower rates of >mild PAR (r = -0.236, p<0.02) with the lowest rate of >mild PAR in patients with area based oversizing ratios >25% and the highest rate in patients with oversizing ratios <15% (0% vs. 15.8%, p<0.02). The rate of postprocedural permanent pacemakers tended to be lower in patients with <15% oversizing compared to those with >25% oversizing (5.3 vs. 16.7%, p<0.23). MSCT guided ESTV-device sizing is safe and is associated with significantly lower than previously reported rates for PAR. A device/annulus oversizing ratio of 15-25% based on area and 7-12% based on mean diameter appears to provide the best risk-benefit ratio in terms of PAR reduction and conduction disorders.

JenaValve

The JenaValve is a next-generation TAVI device which consists of a well-proven porcine root valve mounted on a low-profile nitinol stent. Feeler guided positioning and clip fixation on the diseased leaflets allow for anatomically correct implantation of the device without rapid pacing. Safety and efficacy of transapical aortic valve implantation using the JenaValve were evaluated in a multicentre prospective study that showed good short and midterm results. The valve was CE-mark released in Europe in September 2011. A post-market registry ensures on-going and prospective data collection in "real-world" patients. The transfemoral JenaValve delivery system will be evaluated in a first-in-man study in the near future.