Annular Valve Research Articles

CASE REPORT: SELF–EXPANDING TRANSCATHETER VALVE IMPLANTATION (ACURATE NEO 2) IN A VERY SMALL NATIVE AORTIC ANNULUS

Abstract We present the case of a 74–year–old female, symptomatic for dyspnea on exertion, evaluated by our Cardiac Team for severe aortic valve (AV) stenosis. The transesophageal echocardiography showed a stenotic tricuspid AV (valve area of 0.51 cm2, peak and mean gradients of 75 mmHg and 43 mmHg respectively), normal left ventricle (LV) ejection fraction without significant intraventricular gradient. Pre–operative thoraco–abdominal computed tomography angiography showed an AV without significant calcifications, an aortic annulus perimeter of 51.7 mm (area of 207,8 mm2) and a left ventricular outflow tract (LVOT) perimeter of 45.3 mm with elliptical shape (area of 149,9 mm2). The TAVR procedure was performed with an ‘off–label’ implantation of a SE THV with supra–annular location of leaflets (Acurate Neo 2 23 mm), without any predilation. The post–procedural transthoracic echocardiographic study highlighted the correct positioning of the bioprosthesis without significant protrusion in the LVOT and without any interference with the mitral valve apparatus. The main clinical, technical and procedural considerations have been: According to recommendations, the minimum perimeter of 56.5 mm and the minimum area of 254 mm2 represent the lower limits of the sizing guidelines for THV currently available. We used a SE valve with supra–annular location of the leaflets that offers a potential advantage over BE valves and intra annular SE valves, ensuring a larger effective orifice area. We avoided pre– and post–dilatation to reduce the risk of annular damage and/or rupture The precision of THV implantation (with minimal protrusion in LVOT) was maximized when the rapid pacing during phase 2 of the valve deployment was utilized. A short period of DAPT can be considered in order to prevent a potential increase of thromboembolic events secondary to small aortic valve area. In our opinion the main goal is to prevent high implantation and commissural misalignment in order to facilitate the subsequent coronary percutaneous interventions if needed. Even prophylactic coronary stenting (‘chimney fashion‘) should be avoided unless absolutely necessary. These technical considerations applies also to allow a subsequent valve–in–valve (VIV) procedure, if indicated. To our knowledge, this is among the smallest native aortic annulus so far described and treated percutaneously in a tricuspid stenotic aortic valve with a self–expanding (SE) THV Acurate Neo 2.

What did the transcatheter aortic valve replacement-surgical aortic valve replacement (TAVR-SAVR) trials tell us?

Two families of randomized trials comparing transcatheter aortic valve replacement (TAVR) to surgery for both the Balloon Expandable Valve and the Supra Annular Self-Expanding Valve have been completed to include all surgical risk levels. The result of these trials has led to the approval of TAVR for symptomatic severe aortic stenosis without using risk level as the sole criterion. We have seen an explosion of TAVR in the US to over 98,000 commercial cases in 2022. We have also seen a rapid increase in the use of TAVR in patients less than 65 years of age. With these increases, it is important to ask if they are being driven largely by the data or just the desire for TAVR by both patients and their physicians. Heart team input is a class I indication when deciding between TAVR and surgery. For surgical members of the heart team to appropriately counsel patients, a full understanding of what the TAVR surgery trials tell us as well as what they do not is essential. In this article we will explore those questions.

Design and damping performance analysis of a multistage meandering hybrid valved magnetorheological damper

Abstract The current valved magnetorheological damper has a low space utilization of the piston head, which results in insufficient output damping force, and this paper proposed a multistage meandering hybrid valved magnetorheological damper. The three-dimensional structure of the damper is established and its mathematical model is derived. The electromagnetic field finite element analysis was used to simulate the damper structure, and a comparison was made between the results of traditional annular valve structures and those of multistage meandering hybrid valve. The damping performance of a multistage meandering hybrid valved damper was experimentally studied. The results indicate that the maximum output damping force of the multistage meandering hybrid valved structure is increased by 62.2% over the traditional annular valved structure at a current of 2.4 A and a coil turn count of 350 turns. The structure can effectively utilize the piston head space and improve the output damping force of the damper. The output damping force of the damper reaches 486.4N and the adjustable coefficient K reaches 8.6. The numerical simulation results are the same as the actual experimental results.

Abnormal Shape and Size of the Cardiac Ventricles Are Associated with a Higher Risk of Neonatal Death in Fetuses with Isolated Left Congenital Diaphragmatic Hernia

Introduction: The objective of this study was to evaluate the association between fetal cardiac deformation analysis (CDA) and cardiac function with severe adverse perinatal outcomes in fetuses with isolated left congenital diaphragmatic hernia (CDH). Methods: CDA in each ventricle (contractility, size, and shape), evaluated by speckle tracking and novel FetalHQ software, and markers of cardiac function (E/A ratios, pulmonary and aortic peak systolic velocities, and sigmoid annular valve diameters), were evaluated in fetuses with isolated left CDH. Two evaluations were performed: at referral (CDA and function) and within 3 weeks of delivery (CDA). Severe adverse neonatal outcomes were considered neonatal death (ND) or survival with CDH-associated pulmonary hypertension (CDH-PH). Differences and associations between CDA, cardiac function, and severe adverse outcomes were estimated. Results: Fifty fetuses were included, and seventeen (34%) had severe adverse neonatal outcomes (11 ND and 6 survivors with CDH-PH). At first evaluation, the prevalence of a small left ventricle was 34% (17/50) with a higher prevalence among neonates presenting severe adverse outcomes (58.8 [10/17] vs. 21.2% [7/33]; p = 0.01; OR, 5.03 [1.4–19.1; p = 0.01]) and among those presenting with neonatal mortality (8/11 [72.7] vs. 9/39 [23.0%]; p = 0.03; OR, 8.9 [1.9–40.7; p = 0.005]). No differences in cardiac function or strain were noted between fetuses with or without severe adverse outcomes. Within 3 weeks of delivery, the prevalence of small left ventricle was higher (19/34; 55.8%) with a more globular shape (reduced transverse/longitudinal ratio). A globular right ventricle was significantly associated with ND or survival with CDH-PH (OR, 14.2 [1.5–138.3]; p = 0.02). Conclusion: Fetuses with isolated CDH at risk of perinatal death or survival with CDH-PH had a higher prevalence of a small left ventricle and abnormal shape of the right ventricle.

A Systematic Review of the Design, Method of Implantation and Early Clinical Outcomes of Transcatheter Tricuspid Prostheses.

Intervention for tricuspid regurgitation (TR) tends to happen concurrently with and is addressed during mitral valve surgery. Isolated TR interventions, however, are not unusual and are becoming more common. The purpose of this study was to provide a general overview of the transcatheter tricuspid valve implantation (TTVI) devices, taking into account the several design variations, and to unify the implantation technique, existing clinical results, and potential future directions for TR replacement therapy. The major databases, namely Pubmed via Medline, Embase, and Cochrane library, were systematically searched from the date of conception until 10 February 2023, in accordance with the preferred reporting items for systematic reviews and meta-analyses (PRISMA) standards. Eleven studies were isolated from a total cohort of 5842 publications. All the transcatheter tricuspid prostheses were circular in design yet categorized into annular tricuspid valve implantation (ATVI) and caval valve implantation (CAVI) groups. Bleeding (25.2%), severe access site and vascular issues requiring intervention (5.8%), device migration or embolization (3.6%), and paravalvular leak (38%) are among the early TTVI-related complications that have been observed. The CAVI group experienced 3 of 28 bleeding cases and 2 of 4 device migration cases. Following the intervention with a transcatheter tricuspid prosthesis, this review discovered an early favorable outcome and a general improvement in heart failure symptoms. However, there was a lot of variation in their design, implantation technique, and early clinical outcomes. Understanding the design variations, difficulty of implantation and learning from this review's key findings could help with the future development of catheter-based tricuspid valves. https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022312142.

Relevance of Motion Artifacts in Planning Computed Tomography on Outcomes After Transcatheter Aortic Valve Implantation

BackgroundMotion artifacts in planning computed tomography (CT) for transcatheter aortic valve implantation (TAVI) can potentially skew measurements required for procedural planning. Whether such artifacts may affect safety or efficacy has not been studied. MethodsWe conducted a retrospective analysis of 852 consecutive patients (mean age, 82 years; 47% women) undergoing TAVI-planning CT at a tertiary care center. Two independent observers divided CTs according to the presence of motion artifacts at the annulus level (Motion vs. Normal group). Endpoints included surrogate markers for inappropriate valve selection: annular rupture, valve embolization or misplacement, need for a new permanent pacemaker, paravalvular leak (PVL), postprocedural transvalvular gradient, all-cause death. ResultsForty-six (5.4%) patients presented motion artifacts on TAVI-planning CT (Motion group). These patients had more preexisting heart failure, moderate-severe mitral regurgitation, and atrial fibrillation. Interobserver variability of annular measurement (Normal vs. Motion group) did not differ for mean annular diameter but was significantly different for perimeter and area. Presence of motion artifacts on planning CT did not affect the prevalence of PVL (≥moderate PVL 0% vs. 2.5% p = 0.5), mean transvalvular gradient (6±3 mmHg vs 7±5 mmHg, p = 0.1), or the need for additional valve implantation (0% vs. 2.8%, p = 0.6). One annular rupture occurred (Normal group). Pacemaker implantation, procedural duration, hospital stay, 30-day outcomes, and all-cause mortality did not differ between the groups. ConclusionsMotion artifacts on planning CT were found in about 5% of patients. Measurements for valve selection were possible without the need for repeat CT, with mean diameter-derived annulus measurement being the most accurate. Motion artifacts were not associated with worse outcomes.

Two Rare Cases of Septal, Annular, Valvular, and Ventricular Disorders

Ventricular noncompaction is thought to occur due to the arrest of maturation of the myocardium during fetal development. It may be confined to one or both ventricles. The spectrum of noncompaction varies from an incidental finding to severe systolic and diastolic dysfunction or may manifest as ventricular arrhythmia and thromboembolism. It is known to be associated with congenital heart diseases (CHDs). Annular disjunction is an established morphological entity involving the mitral annulus commonly; although uncommon, it may also involve the tricuspid annulus. Annular disjunction is also commonly associated with atrioventricular (AV) valve regurgitation of various degrees. Association of annular disjunction and AV valve prolapse is known to be associated with ventricular tachyarrhythmia and even sudden cardiac death. The combination of CHD, bi-ventricular non-compaction, annular disjunction, and AV valve prolapse with regurgitation is extremely rare; each of these conditions will be additive to worsen prognosis. Here is a report of two such cases of rare combinations of widely varying morphological features. Whether these morphological alterations are coincidental or a link exists is speculative.

RELATIONSHIP BETWEEN MITRAL ANNULAR CALCIFICATION AND FIRST DEGREE ATRIOVENTRICULAR BLOCK IN ELDERLY

Aim: In this study, we aimed to reveal the relationship between these two degenerative processes, mitral annular calcification, and first-degree AV block. Material and method: The data of 2347 patients over the age of 65 who were examined in the cardiology outpatient clinic. A total of 389 patients with echocardiography results and 12-lead ECGs obtained at the same visit were included in their electronic records. The patient population was divided into two groups as those with or without first-degree AV block, and those with or without mitral annular calcification. Results: Considering the relationship between mitral annular calcification and first-degree AV block, first-degree AV block was observed more frequently in patients with mitral annular calcification, and this was statistically significant. ((Odds ratio: 6.881; 3.107 – 15.236 (95% CI), p<0.001)) Conclusion: In our study, it was observed that first-degree AV block was more common in patients with mitral annular calcification. When these conditions are encountered in clinical follow-ups, the association should be kept in mind, and it should be remembered that a conduction defect may develop in patients with mitral annular calcification or valve pathology may occur in patients with a conduction defect.

Role of Cardiac Computed Tomography in Planning Transcatheter Mitral Valve Replacement (TMVR).

Transcatheter mitral valve replacement (TMVR) is an evolving and rapidly expanding field within structural interventions, offering renewed treatment options for patients with high-risk mitral valve disease. We aim to highlight and illustrate the importance of cardiac CT in the planning of TMVR. As TMVR has evolved, so has the specific nuances of cardiac CT planning, we now understand the importance of accurate annular sizing and valve simulation to predict complications such as neo-LVOT obstruction and paravalvular leak (PVL). More so than any other modality, cardiac CT remains instrumental in accurately planning TVMR from feasibility, device sizing, access, and fluoroscopic angles. Cardiac CT remains the key modality in TMVR evaluation, often the first step in determining patient eligibility through comprehensive procedural planning as well as informing potential outcomes and prognosis. In this review, we discuss the critical role of cardiac computed tomography (CT) and the specific considerations involved in TMVR.

Impact of aortic annular size and valve type on haemodynamics and clinical outcomes after transcatheter aortic valve implantation

Data on patients with small aortic annuli (SAA) undergoing transcatheter aortic valve implantation (TAVI) are limited. We aim to describe the impact of aortic annular size, particularly SAA and TAVI valve type on valve haemodynamics, durability and clinical outcomes. All patients in National Heart Centre Singapore who underwent transfemoral TAVI for severe symptomatic native aortic stenosis from July 2012 to December 2019 were included. Outcome measures include valve haemodynamics, prosthesis-patient mismatch (PPM), structural valve degeneration (SVD) and mortality. A total of 244 patients were included. The mean Society of Thoracic Surgeons score was 6.22±6.08, with 52.5% patients with small aortic annulus (<23mm), 33.2% patients with medium aortic annulus (23-26mm) and 14.3% patients with large aortic annulus (>26mm). There were more patients with self-expanding valve (SEV) (65.2%) versus balloon-expandable valve (BEV) (34.8%). There were no significant differences in indexed aortic valve area (iAVA), mean pressure gradient (MPG), PPM, SVD or mortality across all aortic annular sizes. However, specific to the SAA group, patients with SEV had larger iAVA (SEV 1.19±0.35cm2/m2 vs BEV 0.88±0.15cm2/m2, P<0.01) and lower MPG (SEV 9.25±4.88 mmHg vs BEV 14.17±4.75 mmHg, P<0.01) at 1 year, without differences in PPM or mortality. Aortic annular size, TAVI valve type and PPM did not predict overall mortality up to 7 years. There was no significant difference in SVD between aortic annular sizes up to 5 years. Valve haemodynamics and durability were similar across the different aortic annular sizes. In the SAA group, SEV had better haemodynamics than BEV at 1 year, but no differences in PPM or mortality. There were no significant differences in mortality between aortic annular sizes, TAVI valve types or PPM.

Ventricular arrhythmias following transcatheter pulmonary valve replacement with the harmony TPV25 device.

Transcatheter pulmonary valve replacement (TPVR) with the Harmony valve (Medtronic, Inc.) was recently approved to treat postoperative native outflow tract pulmonary regurgitation. While the 22 mm Harmony valve Early Feasibility Study demonstrated ventricular tachycardia (VT) in only 5% of patients, little is known about ventricular arrhythmias after TPVR with the larger 25 mm valve (TPV25). A single center review was performed of patients with TPV25 implant from 2020 to 2021. Demographic, cardiac, procedural, and postimplant cardiac telemetry data were collected and compared between patients who did and did not have peri-implant ventricular arrhythmia. Thirty patients underwent TPV25 at a median age of 30 years. On postimplant telemetry, VT events were documented in 12 patients (40%); 11 nonsustained VT (NSVT) (median 3 episodes per patient and 6 beats per episode, maximum 157 episodes) and 1 sustained VT (3%), with Torsades de Pointes secondary to a short coupled premature ventricular contraction (PVC). VT events were associated with annular valve positioning (p &lt; 0.001) and increased postimplant PVC burden (p &lt; 0.0001), but there was no association between VT and other demongraphic, historical, or procedural factors. The frequency of NSVT events fell from 3/hfrom 0 to 12 h postimplant to 0.5/hr from 12 to 24 h (p &lt; 0.001). VT occurred commonly (40%) in the first 24 h after TPV25 implant, with self-limited NSVT in 11 of 12 patients and 1 patient with cardiac arrest secondary to Torsades de Pointes. VT only occurred with annular valve positioning. Larger, longer-term studies are needed to determine risk factors for and natural history of post-TPVR VT.

Evaluation of non-breath-hold, ultra-fast, low-dose high-pitch (flash) CT scan as a practical alternative to standard spiral scan for pre-TAVI patients: a real-world single-center experience

Abstract Introduction and aim Aortic annulus dimensions change during the cardiac cycle. A retrospective ECG-gated (Spiral) scan is the default technique for pre TAVR evaluation since it includes systolic phases considered optimal for aortic annulus assessment. Ultra-fast, Low-Dose High-Pitch (FLASH) offers faster, potentially low radiation and low contrast dose scans. However, it lacks the ability to time data acquisition to the systole. Therefore, measurements derived from FLASH scan are considered suboptimal for reporting. The effect of this potential annular measurement difference on procedural success and safety was not evaluated. Therefore, we aimed to assess the feasibility and safety of FLASH vs. Spiral scan before TAVI. Methods We conducted a retrospective, single-center study. 409 patients underwent CT-TAVI scan with either FLASH or SPIRAL acquisition. Baseline characteristics, CT study, procedural and f/u data were acquired from the EMR. Outcomes defined by Valve Academic Research Consortium3 (VARC-2) endpoint definitions included in-hospital mortality, bleeding, vascular complications, acute kidney injury (AKI), conduction disorders, mechanical complications, and prosthetic aortic valve regurgitation. Composite endpoints such as device success were also examined. Results Of the 409 patients, 55.7% underwent FLASH scans. The median age was 80 years, and males accounted for 55%. The FLASH-protocol patients had higher rate of chronic kidney disease, their CT-measured aortic annulus area and diameter were smaller, and they were exposed to a smaller amount of contrast agent and radiation than the SPIRAL group. There was no statistically significant difference in primary clinical and safety endpoints between the two groups, including mechanical complications (such as annular rupture and valve malposition) and conduction disorders. Conclusions FLASH CT scan is a pragmatic and safe approach that potentially may replace spiral scan for the evaluation before TAVI procedure in the appropriate patients. Funding Acknowledgement Type of funding sources: None.

Natural History of Mitral Annular Calcification and Calcific Mitral Valve Disease

The natural history of mitral annular calcification (MAC) and risk for developing calcific mitral valve disease (CMVD) have been poorly defined. The aim of this study was to evaluate the progression rate of MAC and of the development of CMVD. Patients with MAC and paired echocardiograms ≥1year apart between 2005 and 2019 were included. Progression rates from mild or moderate to severe MAC and to CMVD (defined as severe MAC and significant mitral stenosis and/or regurgitation) were assessed, along with potential association with sex. A total of 11,605 patients (mean age, 73±10years; 51% men) with MAC (78% mild, 17% moderate, 5% severe) were included and underwent follow-up echocardiography at 4.2±2.7years. Among patients with mild or moderate MAC, 33% presented with severe MAC at 10years. The rate of severe MAC was higher in women than in men (41% vs 24% [P<.001]; hazard ratio, 1.3; P<.001) and in patients with moderate versus mild MAC (71% vs 22% [P<.001]; hazard ratio, 6.1; P<.001). At 10years, 10% presented with CMVD (4%, 23%, and 60% in patients with mild, moderate, and severe MAC, respectively), which was predicted by female sex (15% vs 5%; P<.0001), even after adjustment for MAC severity (hazard ratio, 1.9; P<.001). In this large cohort of patients with MAC, progression to severe MAC was common and frequently resulted in CMVD. Female sex was associated with higher progression rates. MAC and CMVD are expected to dramatically increase as the population ages, highlighting the importance of a better understanding of the pathophysiology of MAC to develop effective preventive medical therapies.

Influence of Support Surface Shape of a Stationarily Installed Elastic Valve on the Change in Pre-impact Velocity of Impact Machine Striker

The dynamic contact problem of the interaction between the impact machine striker and a conical annular elastic valve made of elastomer (rubber), which choks the reverse motion chamber in impact machines for mining and construction, is considered. The influence of the shape of the valve support surface on the drop in the pre-shock velocity of the striker during contact interaction is studied. Variants of the shape of the supporting surface of the valve are founded, at which the smallest drop in velocity is observed. For two variants, the dependence of the change in the decrease of the pre-impact velocity with an increase in the elastic properties of the elastomer was obtained. It is proved that with an increase in the elastic properties of the material, the drop in pre-impact velocity increases linearly, and for support surface shape that previously showed a smaller velocity drop, the pre-impact velocity drops less with increasing modulus of elasticity.

Analysis of FSC Supercharged Engine Intake Front End

This paper is based on the simulation analysis of the supercharger front intake pipeline of the FSAE racing car engine. To limit engine power, the equation race requires an annular restrictor valve to be installed in the intake system with an inner diameter less than 20mm. Limiting valves have a great impact on the intake flow and engine performance. In this paper, the intake front segment is modeled, the simulation analysis is done by Fluent, and the GT-power engine simulation software is used to assist the simulation. A good intake front segment is obtained, which provides an effective method for the design of the intake front of supercharger engine.

ТОПЛИВОПОДАЮЩАЯ СИСТЕМА НЕПОСРЕДСТВЕННОГО ДЕЙСТВИЯ С ЭЛЕКТРОННО-УПРАВЛЯЕМЫМ КОЛЬЦЕВЫМ КЛАПАНОМ

The studies were carried out with the aim of developing a method for skipping fuel supplies (turning off individual working piston strokes) at low crankshaft rotational speeds and at partial engine operating modes at low load in direct-acting fuel supply systems to improve fuel efficiency. The developed method is easily implemented using an electronically controlled ring-type discharge valve. A valve made in the form of rigid elastic ring and installed in the high-pressure line above the plunger pair regulates fuel skip. An electromagnet located in the cavity of the annular valve controls it using an electronic regulator, acting at the right time according to the signals coming from the sensors of the engine crankshaft speed, the volume of incoming air and the position of the piston. The proposed fuel supply system of direct action with an electronically controlled annular valve reliably ensures the speed and load characteristics of the engine by influencing the number of cycle fuel supplies. With a decrease in the load and speed of the engine crankshaft, the number of fuel supply cycle’s decreases due to a decrease in signals to the electromagnet winding and, as a result, the valve is not attracted and the fuel supply is skipped. A decrease in the unevenness of the fuel supply in terms of the dynamic component that occurs when the supply is turned off is ensured by a decrease in the inertia of the regulator action due to the electronic control of the annular valve. The developed mathematical model of a direct-acting fuel supply system with an annular pressure valve makes it possible to reveal the relationship between the fuel supply parameters and the design dimensions of the split ring. Such a fuel supply system of direct action with an electronically controlled delivery valve allows, due to skipping of working strokes in low load and idle modes, redistributing the provided volume of fuel to working cylinders, significantly reduce fuel consumption

ТОПЛИВОПОДАЮЩАЯ СИСТЕМА НЕПОСРЕДСТВЕННОГО ДЕЙСТВИЯ С ЭЛЕКТРОННО-УПРАВЛЯЕМЫМ КОЛЬЦЕВЫМ КЛАПАНОМ

The studies were carried out with the aim of developing a method for skipping fuel supplies (turning off individual working piston strokes) at low crankshaft rotational speeds and at partial engine operating modes at low load in direct-acting fuel supply systems to improve fuel efficiency. The developed method is easily implemented using an electronically controlled ring-type discharge valve. A valve made in the form of rigid elastic ring and installed in the high-pressure line above the plunger pair regulates fuel skip. An electromagnet located in the cavity of the annular valve controls it using an electronic regulator, acting at the right time according to the signals coming from the sensors of the engine crankshaft speed, the volume of incoming air and the position of the piston. The proposed fuel supply system of direct action with an electronically controlled annular valve reliably ensures the speed and load characteristics of the engine by influencing the number of cycle fuel supplies. With a decrease in the load and speed of the engine crankshaft, the number of fuel supply cycle’s decreases due to a decrease in signals to the electromagnet winding and, as a result, the valve is not attracted and the fuel supply is skipped. A decrease in the unevenness of the fuel supply in terms of the dynamic component that occurs when the supply is turned off is ensured by a decrease in the inertia of the regulator action due to the electronic control of the annular valve. The developed mathematical model of a direct-acting fuel supply system with an annular pressure valve makes it possible to reveal the relationship between the fuel supply parameters and the design dimensions of the split ring. Such a fuel supply system of direct action with an electronically controlled delivery valve allows, due to skipping of working strokes in low load and idle modes, redistributing the provided volume of fuel to working cylinders, significantly reduce fuel consumption

Peripheral intravascular lithotripsy for transcatheter aortic valve implantation: a multicentre observational study.

The presence of severe calcific atherosclerosis at the iliofemoral axis may preclude transcatheter aortic valve implantation (TAVI) by the transfemoral (TF) approach. Intravascular lithotripsy (IVL) is a novel technology that fractures intimal/medial calcium and increases vessel compliance allowing TF TAVI in selected patients with peripheral artery disease (PAD). The aim of this study was to report on the safety and efficacy of IVL-assisted TF TAVI in an all-comers population. Clinical, imaging and procedural data on all consecutive patients treated by IVL-assisted TF TAVI in six high-volume European centres (2018-2020) were collected in this prospective, real-world, multicentre registry. IVL-assisted TF TAVI was performed in 108 patients, increasing from 2.4% to 6.5% of all TAVI from 2018 to 2020, respectively. The target lesion was most often localised at the common and/or external iliac artery (93.5% of cases; average TL-MLD 4.6±0.9 mm with 318 degrees of calcium arc). Transfemoral aortic valve delivery was successful in 100% of cases; final procedural success in 98.2% (two conversions to cardiac open surgery for annular rupture and valve migration). Complications of the IVL-treated segments consisted of 1 perforation and 3 major dissections requiring stent implantation (2 covered stents and 2 BMS). Access-site-related complications included 3 major bleedings. Three in-hospital deaths were recorded (2.8%, 1 failed surgical conversion after annular rupture, 1 cardiac arrest after initial valvuloplasty, 1 late hyperkalaemia in renal dysfunction). IVL-assisted TF TAVI proved to be a safe and effective approach, which helps to expand the indications for TF TAVI in patients with severe calcific PAD. However, these patients continue to have a higher-than-average incidence of periprocedural complications.

Transcatheter Aortic Valve Replacement for Severe Aortic Regurgitation in Patients With a Left Ventricular Assist Device.

There are limited invasive treatment options for patients with end-stage heart failure and left ventricular assist device (LVAD) who develop severe aortic valve regurgitation (AR). One option for such patients is transcatheter aortic valve replacement (TAVR). There are limited data on outcomes of patients with LVAD who receive TAVR for severe AR. We present a series of 4 consecutive patients with LVAD who underwent TAVR for severe AR. This is a retrospective chart review of 4 consecutive patients with LVAD who underwent TAVR for severe AR. All 4 patients underwent TAVR with a 34-mm self-expanding valve (Medtronic). One patient received a 29-mm balloon-expandable valve (Edwards Lifesciences) within the self-expanding valve (SEV) to postdilate the SEV and minimize paravalvular leak (PVL). All 4 procedures were technically successful. The patient who received rescue valve-in-valve TAVR continued to have persistent mild to moderate PVL. Although technically challenging, TAVR is a feasible option for carefully selected LVAD patients with severe AR. Procedural issues to consider include oversizing the transcatheter heart valve (THV) while being cognizant of the risks of annular rupture and valve dislocation, anticipating and avoiding ventricular migration of the THV and being ready to postdilate the THV if necessary, to limit hemodynamically significant PVL.

Modernization of the fuel supply system in the internal combustion engine by electronic control of the ring valve

The research was carried out in order to develop a method for skipping fuel supplies (turning off individual piston strokes) at low frequencies of crankshaft rotations and at partial engine operating modes with direct-acting fuel supply systems to increase fuel efficiency. The developed method is easily implement using a ring-type discharge valve with electronic control. A valve made in the form of a split elastic ring and installed in a high-pressure line above the plunger pair controls the fuel supply. An electromagnet, located in the cavity of the annular valve, controls the valve, using an electronic regulator, acting at the right moment according to the signals coming from the sensors of the engine crankshaft speed, the volume of incoming air and the position of the piston. The proposed direct-acting fuel supply system with an electronically controlled ring valve reliably ensures the speed and load characteristics of the engine by affecting the number of cyclic feeds. With a decrease in the load and speed of the engine crankshaft, the number of cyclic fuel supplies decreases due to a decrease in signals sent to the electromagnet winding and, as a result, the valve does not attract the fuel and misses the fuel supply. Reducing the unevenness of the fuel supply by the dynamic component that occurs when the supply is switch off is ensured by reducing the inertia of the regulator due to the electronic control of the ring valve. The developed mathematical model of a direct-acting fuel supply system with an annular discharge valve allows us to reveal the relationship of fuel supply parameters with the design dimensions of the split ring. Such direct-acting fuel supply system with an electronically controlled discharge valve allows, due to the skipping of working strokes in low-load and idle modes, redistributing the provided amount of fuel to the working cylinders, significantly reducing fuel consumption.