Radial Force: An Underestimated Parameter in Oversizing Transcatheter Aortic Valve Replacement Prostheses: In Vitro Analysis with Five Commercialized Valves.

The goal is to inform in depth on transcatheter aortic valve replacement (TAVR) prosthesis mechanical behavior, depending on frame type, design, and size, and how it crucially impacts the oversizing issue in clinical use, and ultimately the procedure outcome. Transcatheter aortic valve replacement is an established therapy for high-risk patients suffering from aortic stenosis, and the indication for TAVR is progressively expanding to intermediate-risk patients. Choosing the optimal oversizing degree is crucial to safely anchor the TAVR valve-which involves limiting the risks for embolism, aortic regurgitation, conductance disturbance, or annulus rupture-and to increase the valve prosthesis performance. The radial force (RF) profiles of five TAVR prostheses were measured in vitro: the CoreValve 23 and 26 (Medtronic, Minneapolis, MN), the Acurate neo S (Symetis, Écublens, Vaud, Switzerland), and the SAPIEN XT 23 and 26 (Edwards Lifesciences, Irvine, CA). Measurements were run with the RX Machine equipment (Machine Solutions Inc., Flagstaff, AZ), which is used in ISO standard tests for intravascular stents. Test protocols were adapted for TAVR prostheses. With the prostheses RF profiles' results, mechanical behavior differences could be described and discussed in terms of oversizing strategy and clinical impact for all five valves. Besides, crossing the prostheses' RF profiles with their recommended size windows made the assessment of borderline size cases possible and helped analyze the risks when accurate measurement of patient aortic annulus proves difficult. The prostheses' RF profiles bring new support in clinical decision-making for valve type and size in patients.

The flutter-by effect: a comprehensive study of the fluttering cusps of the Perceval heart valve prosthesis.

OBJECTIVES: Sutureless aortic valve prostheses are gaining popularity due to the substantial reduction in cross-clamp time. In this study, we report our observations on the cusp-fluttering phenomenon of the Perceval bioprosthesis (LivaNova, London, UK) using a combination of technical and medical perspectives. METHODS: Between August 2014 and December 2016, a total of 108 patients (69% women) with a mean age of 78 years had aortic valve replacement using the Perceval bioprosthesis (34 combined procedures). All patients underwent transoesophageal echocardiography (TOE) intraoperatively. TOE was performed postoperatively to detect paravalvular leakage and to measure gradients, acceleration time, Doppler velocity indices (Vmax and LVOT/Vmax AV) and effective orifice area indices. In addition, a TOE examination was performed in 21 patients postoperatively. Data were collected retrospectively from our hospital database. RESULTS: The retrospective evaluation of the intraoperative TOE examinations revealed consistent fluttering in all patients with the Perceval bioprosthesis. The echocardiographic postoperative measurements showed a mean effective orifice area index of 0.91 ± 0.12 cm2/m2. The overall mean pressure and peak pressure gradients were in a higher range (13.5 ± 5.1 mmHg and 25.5 ± 8.6 mmHg, respectively), whereas acceleration time (62.8 ± 16.4 ms) and Doppler velocity indices (0.43 ± 0.11) were within the normal range according to the American Society of Echocardiography or european association of echocardiography (EAE) guidelines. The 2-dimensional TOE in Motion Mode (M-Mode) that was performed in patients with elevated lactate dehydrogenase (LDH) levels revealed remarkable fluttering of the cusps of the Perceval bioprosthesis. CONCLUSIONS: In our study cohort, we observed the fluttering phenomenon in all patients who received the Perceval bioprosthesis, which was correlated with elevated LDH levels and higher pressure gradients.

Preclinical determination of the best functional position for transcatheter heart valves implanted in rapid deployment bioprostheses.

AIMS: The aim of this study was to determine the best functional position of a transcatheter heart valve (THV) implanted as a valve-in-valve (ViV) procedure in small rapid deployment valves (RDV) in an in vitro model. METHODS AND RESULTS: A 21 mm Perceval, Enable or INTUITY RDV was mounted into a pulse duplicator and a 23 mm balloon-expandable or a self-expanding THV was deployed (valve-in-valve) in two different positions. Under physiological hydrodynamic conditions, the performance of the THV was characterised by mean transvalvular pressure gradient (MPG), effective orifice area (EOA) and regurgitation volume (RV). Leaflet kinematics were assessed with high-speed video recordings, and X-ray images were acquired. All THV/RDV combinations met ISO requirements regarding hydrodynamic performance. In most cases, the higher position of the THV performed better than the lower one in terms of a lower MPG and increased EOA. Leaflet motion of the implanted THV was impaired in the lower position. In contrast, regurgitation volumes were relatively small and similar, regardless of the THV position. CONCLUSIONS: ViV implantation of a THV in a small RDV yielded satisfactory hydrodynamic results. In most cases, a high implantation position achieved lower MPG, higher EOA and a reduced risk of impaired THV leaflet function. Fluoroscopy images of the best functional ViV positions are presented as a blueprint for patient procedures.

Valve-in-valve outcome: design impact of a pre-existing bioprosthesis on the hydrodynamics of an Edwards Sapien XT valve.

Objectives: Bioprosthetic aortic heart valves are increasingly implanted in younger patients. Therefore, a strategy for potential valve failure should be developed before implanting the 'first valve'. The goal of this in vitro study was to provide insight into the effects of the design of a bioprosthesis on a valve-in-valve implanted Sapien XT valve. Methods: The hydrodynamic performance of a 23-mm Sapien XT valve implanted in Vascutek Aspire, Edwards Perimount, Medtronic Mosaic and St. Jude Medical Trifecta heart valves was investigated in a left heart simulator. In addition to the hydrodynamic results, the leaflet dynamics were analysed in high-speed video recordings of the tests. Results: All valve-in-valve combinations in this study fulfilled the minimum acceptance criteria defined by relevant approval standards (e.g. ISO 5840) but displayed significant differences in their performances. Small inner diameters of the bioprostheses were associated with increased mean pressure gradients, decreased effective orifice areas and geometric opening areas as well as with pin-wheeling and uneven leaflet motion. In addition, implantation in bioprostheses with internally mounted leaflets was associated with lower paravalvular leakage. Conclusions: The results of this study suggest that a surgical bioprosthesis with a large inner diameter and internally mounted leaflets improves the heamodynamics and potentially the durability of a valve-in-valve combination. These results should give the attending physicians critical information to consider when deciding on a bioprosthesis for younger patients.

What can be done for cerebral embolic protection in TAVI? Analysis in the light of 10 years' experience with protected carotid artery stenting.

In the last 30 years, development of minimally invasive percutaneous procedures to treat cardiovascular defects has been thriving. Although these techniques present obvious advantages, like avoiding cardiopulmonary bypass, the passage of catheter systems and the deployment of devices in the blood circulation can cause particle embolization that may result in stroke. In carotid artery stenting, cerebral embolic protection devices (CEPD) such as filtering membranes have been available for already 10 years. In transcatheter aortic valve implantation (TAVI), the development of CEPD is starting and three membrane-based devices are in clinical trials. There are controversial discussions about the efficacy of CEPD in TAVI. The experience with CEPD in carotid artery stenting can help to understand some of the technical issues and shortcomings of current devices and thereby ultimately reduce cerebral complication risks during TAVI procedures.

Calcium distribution patterns of the aortic valve as a risk factor for the need of permanent pacemaker implantation after transcatheter aortic valve implantation.

AIMS: New-onset conduction disturbances still represent a considerable problem after transcatheter aortic valve implantation (TAVI). The aim of this study was to identify calcification patterns with an elevated risk for permanent pacemaker implantation (PPI) after TAVI and investigate underlying mechanisms in an ex vivo setting. METHODS AND RESULTS: One hundred and sixty-two patients who underwent TAVI with the Edwards SAPIEN XT® or Medtronic CoreValve® at our institution were analysed. The calcium load of the device landing zone was quantified with 3mensio®, and calcium patterns with an elevated risk for PPI were identified. Ex vivo simulations of balloon valvuloplasty were performed in 3D-printed silicone annuli of patients matching the identified risk profile. Patients with a calcium load of the left coronary cusp (LCC) above 209 mm3 had a higher rate of PPI than patients below this threshold (16.7 vs. 2.6%, P = 0.003). Multivariate regression revealed pre-existing right bundle branch block (RBBB) and increased LCC calcification as independent predictors for PPI. Simulation of the TAVI procedure in a silicone annulus revealed an off-centreline shift of the valvuloplasty balloon and transcatheter heart valve away from the LCC towards the commissure between right- and non-coronary cusp. CONCLUSION: Pre-existing RBBB and elevated LCC calcification were identified as independent predictors for PPI. These two risk factors enabled us to distinguish between patients according to their risk for PPI after TAVI. Ex vivo simulations suggested an off-centreline shift of the balloon as a possible explanation.

Right heart transcatheter valve therapies - a review of prostheses for the pulmonary and tricuspid positions.

Minimally invasive, catheter-based treatment of valvular dysfunction has become an integral part of clinical routine. As left heart valvular disease is much more common and thus commercially of interest, transcatheter solutions for the treatment of aortic and mitral valvular defects were the first to become broadly clinically available, while even today options for the right heart valve are rare. This review looks at innovative attempts at developing effective transcatheter heart valve prostheses for the pulmonary and tricuspid heart valves, details their experience and highlights those that have made their way to application in humans.