Small Valve Research Articles

Peri-procedural outcome according to VARC-3 criteria and hemodynamic mid-term follow-up after Valve-in-valve transcatheter aortic valve replacement for failed aortic bioprosthesis.

Despite the widespread adoption of valve-in-valve transcatheter aortic valve replacement (VIV-TAVR) for patients with failed aortic bioprosthesis, the effectiveness of this treatment for Japanese patients frequently associated with small aortic annuli remains unclear. From December-2011 to October-2022, 41 consecutive patients undergoing VIV-TAVR were enrolled in this study. The endpoints were technical success, device success, early safety, and two-year mortality according to implanted surgical valve size (small valves: 19-mm and 21-mm, n = 23; large valves: 23-mm and 25-mm, n = 18). The patient population had a mean age of 80.5years, 46.3% male. Technical success, device success, and early safety rates were 100%, 70.7%, and 87.8%, respectively. There was no significant increase in the transprosthetic gradient throughout the follow-up (mean pressure gradient pre-VIV, post-VIV, at one-year, and at two-year; 37.0mmHg, 16.5mmHg, 15.0mmHg, and 12.0mmHg, respectively). While technical success and two-year mortality were comparable (87.5% vs. 86.7%, log-rank p = 0.816), device success was significantly lower in the small valves than in the large valves (56.5% vs. 88.9%, p = 0.038). Early safety trended lower in the small valves. Valve hemodynamic performance improved in both groups, but severe prosthesis-patient mismatch was more common in the small valves. VIV-TAVR demonstrated acceptable technical performance and relatively low mid-term mortality in this Japanese population, irrespective of aortic annular size. However, device success and early safety were significantly worse in patients with small valves than in those with large valves.

Discovery of a new moss-associated diatom species, Humidophila caribaea (Bacillariophyceae: Diadesmidaceae), from terrestrial habitats of the Monts Caraïbes, Guadeloupe

During the investigation of diatom diversity of terrestrial moss samples collected on Basse-Terre, Guadeloupe, French West Indies, a new species of the genus Humidophila (Lange-Bertalot & Werum) Lowe et al. was observed. The species occurred in only one sample collected from tropical, mesophytic forests in the Monts Caraïbes and could not be identified based on the literature data. Based on the set of morphological features the species is described herein as Humidophila caribaea sp. nov. The species is characterized by the small valve size, typical for the Humidophila genus, but it has a unique morphology of the areolae with small silica warts in their lumen. Additionally, a comparison with most similar taxa known worldwide, as well as ecological notes are provided.

Molecular phylogeny, morphology and distribution of Amphitetras antediluviana Ehrenberg from the Black Sea and the Sea of Azov

The intriguing large-celled species of Amphitetras antediluviana Ehrenberg was originally described as a fossil species (Ehrenberg, 1840), but later noted in a living state in various regions of the World ocean. Our recent studies revealed that the species has been found for the last decade in significant numbers in many habitats along the coast of the Azov-Black Sea basin. Two strains—the large valves from Laspi Bay, the Black Sea (BL-5_12092019) and the small valves from the Sea of Azov (AZ-12_24122019)—were isolated and analyzed using light and scanning electron microscopy along with molecular-genetic investigation. Specimens of the two populations differ in valve sizes and structure, however, their belonging to the same species was confirmed with the help of molecular analysis. Taxonomic positions of the strains of A. antediluviana isolated from two marine waterbodies were clarified. In addition, we provided a detailed morphological diagnosis of the species with a description of the valve ultrastructure and its elements, as well as geographical distribution and taxonomic history.

Performance Characteristics of a Compact Core Annular-Radial Magnetorheological Damper for Vehicle Suspension Systems

The magnetorheological (MR) damper is a by-wire system capable of providing variable damping stiffness by responding to an apparent magnetic field. In response to the magnetic field application, the magnetorheological fluid (MR fluid) exhibited altered behavior within the damper. Typically, a damper’s internal and external valves operate in flow mode, where the flow is regulated by controlling the magnetic field. This study aims to investigate the performance characteristics of a small core annular and radial magnetorheological valve (SCARMV) designed for applications in vehicle suspension systems. The proposed design of the simplified MR valve is based on a meandering-type valve composed of multiple valve cores that have been simplified to a single core. Dynamic testing was performed on the proposed valve, which features a single rod tube damper, to investigate the damping force characteristics by varying currents and frequencies. The characteristics of the measured damping force were compared to the calculated damping force based on the pressure drop calculation and the FEMM simulation of magnetic flux. By increasing the stroke length of the valve travel is set to 10 mm at a current input of 0 A to 1.0 A, the maximum output of the MR valve damping force was approximately 1.57 kN. In addition, a mathematical model of SCARMV is presented and compared to the experimental data. Therefore, based on the experimental results, it was concluded that the usability of a compact core MR valve is reliable. However, more in-depth studies are required before these dampers can be applied to vehicle suspension systems.

Glabrobournonia Morris and Skelton (Rudist, Bivalvia) from the Campanian–Maastrichtian of Türkiye: Taxonomy, palaeoecology and palaeobiogeography

A re-examination of the specimens described as Bournonia anatolica Özer and Bournonia sp. from central and southeastern Anatolia, Türkiye reveals that they have diagnostic characteristics of the genus Glabrobournonia Morris and Skelton. New rudist material from the middle Campanian to late Maastrichtian mixed siliciclastic-carbonate sequences in the Sakarya Zone (Eastern and Central Pontides), in the east of the Anatolid–Tauride Block and in southeastern Anatolia (north of the Arabian Platform) in Türkiye also showed the occurrence of Glabrobournonia anatolica (Özer) and Glabrobournonia arabica Morris and Skelton. Glabrobournonia anatolica is characterised by a large, rectangular right valve with pronounced growth lamellae, a salient ventral carina and interband, a less salient dorsal carina, a concave indentation anterior band, a slightly concave posterior band and broad and smooth anterior surface as well as the absence of radial ribbing and ligamentary infolding. Glabrobournonia arabica has the diagnostic features of the species, such as small valves, conical right valves with a smooth surface, ventral and dorsal carinae and two concave indentations of anterior and posterior bands separated by an interband. The palaeoecological characteristics of these lateral clinger morphotypes are presented according to growth geometries. For the cosmopolitan genus Glabrobournonia, two main migration routes have been proposed for the Campanian–Maastrichtian time: one along the southern margin of the Tethys from the United Arab Emirates–Oman border region to the Zagros (Iran) and southeastern Anatolia, connecting to the northern margin of the Tethys to the Anatolid–Tauride Block and the Sakarya Zone in Türkiye, and another from the United Arab Emirates–Oman border region to the Zagros Zone (Iran) and the Tarim Basin, connecting the northern and southern margins of the eastern Tethys.

Aortic valve calcium score to mean gradient ratio: a new frontier in aortic stenosis prognostication

Abstract Introduction Aortic stenosis (AS) presents diagnostic challenges, especially in patients with discordant low gradient AS (LGAS), i.e., small aortic valve area (AVA) and low Doppler mean gradient (MG). LGAS is associated with worse outcomes compared to concordant AS. Aortic valve calcium score (AVCS) is a measure of AS severity independent of flow and helps diagnose severe AS. It is unknown if the degree of discordance in AVCS and MG is of any clinical significance. A high AVCS/MG ratio may indicate impaired ventricular function and response to pressure overload despite preserved LVEF, potentially contributing to worse outcomes. Purpose This study aims to elucidate the prognostic significance of the AVCS/MG ratio in patients with severe AS and preserved left ventricular ejection fraction (LVEF) undergoing TAVR. We hypothesized a higher AVCS/MG ratio correlates with increased mortality. Methods Patients who underwent transcatheter aortic valve replacement (TAVR) from 2010 to 2020 for native valve severe AS with LVEF≥50% were identified from an institutional database. AVCS were obtained within 90 days of pre-TAVR echocardiography. Patients were divided into tertiles based on their AVCS/MG ratio. Primary outcome was overall mortality. Results The analysis included 1067 patients (mean age 79±9 years, 43% female); overall AVA was 0.80±0.14 cm², LVEF 63±6%, MG 46±12 mmHg, AVCS 2630±1528 AU, and AVCS/MG ratio 58±31. Patients stratified by AVCS/MG tertiles showed no difference in overall comorbidity index across tertiles (Figure 1). However, the group in the highest tertile was the oldest (80±8 vs 79±8 vs 77±9 years), predominantly male (87% vs 61% vs 24%), with the highest prevalent atrial fibrillation (44% vs 28% vs 25%) and stroke volume index <35 mL/m² (16% vs 11% vs 5%). 9-year survival was 15% vs 25% vs 36% (p<0.001, Figure 2). In multivariate analysis adjusted for age, sex, comorbidities, LVEF and AVA, AVCS/MG ratio was independently associated with increased risk of mortality (HR 1.005; 95% CI [1.001-1.008], p=0.005). Conclusion Higher AVCS/MG discordance is associated with increased risk of mortality following TAVR. Serial AVCS measurements during progressive AS may help identify patients at higher risk who may potentially benefit from earlier aortic valve intervention.

The impact of prosthesis-patient mismatch on clinical outcomes in patients undergoing transcatheter aortic valve implantation

Abstract Background There is considerable debate on the impact of prosthesis-patient mismatch (PPM) after transcatheter aortic valve implantation (TAVI) on clinical outcomes. Objectives This study aimed to assess the impact of PPM after TAVI on clinical outcomes. Methods The current study population included 467 patients undergoing TAVI at our Hospital between 2014 and 2023. PPM was defined as moderate if ≥0.65 but <0.85 cm2/m2 (≥0.55 but <0.70 cm2/m2 if obese: body mass index>30 kg/m2) or severe if <0.65 cm2/m2 (<0.55 cm2/m2 if obese) at the indexed effective orifice area measured by transthoracic echocardiography at discharge. The primary outcome was a composite of all-cause death or heart failure hospitalization. Median follow-up duration was 2 years (Interquartile: 0.9 - 4.0 years). Results The median age of the current study population was 83.9 years. Moderate and severe PPM were seen in 78 (17%) and 11 (2%) patients, respectively. The factors associated with PPM included small valve size (SAPIEN 20 mm or CoreValve/Evolut 23 mm), balloon-expandable valves, and atrial fibrillation, but not post dilatation. There was no significant difference of the incidence of PPM between SAPIEN XT and SAPIEN 3 (21% and 21%, P= 0.98). PPM was not seen in SAPIEN 3 Ultra RESILIA (n= 0/10). The cumulative 3-year incidences of the primary outcome after TAVI were not significantly different between patients with and without PPM (22% and 27%, P= 0.42) (Figure 1 and 2). There was no significant difference of the primary outcome between patients with and without elevated (>20 mmHg) post-TAVI gradient (18% and 27%, P= 0.17). After adjusting confounders, the excess risk of PPM at discharge for the primary outcome was not significant (adjusted hazard ratio: 0.86, 95% confidence interval: 0.56-1.31, P= 0.48). Conclusions PPM was not associated with worse clinical outcomes in contemporary patients undergoing TAVI.Kaplan-Meier analysis and log-rank testcumulative incidence

Design and Analysis of High Precision Flow Proportional Regulating Valve Based on Piezoelectric Drive

Abstract With the development of micro-satellite propulsion system towards high precision, light and miniaturization, higher requirements are put forward for precise adjustment of propulsion system. Based on the principle of piezoelectric micro-displacement drive, this paper designs a light and small proportional flow control valve, adopts compliant amplification mechanism, develops the throttling design of small flow in the form of valve needle, analyzes the flow characteristics in the proportional adjustment process under different parameters, and realizes the micro-flow control ability with a flow control range of 0∼2mg/s and a flow control accuracy better than 3%. This design and analysis method can meet the needs of large-scale and high-precision flow control, and provide technical support for subsequent engineering applications.

Trends and Outcomes of Aortic Root Enlargement During Bioprosthetic Aortic Valve Replacement

BackgroundAortic root enlargement (ARE) during aortic valve replacement (AVR) mitigates prosthesis-patient mismatch, but its use has been low. Transcatheter aortic valve-in-valve (VIV) as a treatment for failing bioprosthetic valves is limited by small surgical valves, renewing interest in ARE during the index AVR. This study demonstrates trends and outcomes of ARE after commercial approval of VIV in 2015. MethodsThis retrospective cohort study analyzed 2182 patients undergoing nonemergent AVR between August 2007 and December 2022. Endocarditis, aortic dissection, and concomitant root replacement or ventricular assist device placement were excluded. Trends in ARE use, valve size, and types were compared. Outcome measures included 30-day mortality and gradients and were compared between patients with and without ARE. ResultsOverall, 74 patients (3.4%) underwent ARE, 14 (1.0%) before 2015 and 60 (7.6%, P < .0001) after 2015. Use of smaller valves (19-21 mm) decreased from 372 (26.8%) before 2015 to 85 (10.7%, P < .0001) after 2015. ARE group was younger than the AVR-alone group (64 vs 68 years, P = .001) but had similar predicted risk of mortality (median, 1.7%). Both groups had comparable postoperative mean gradients (ARE: 11 vs AVR-alone: 10 mm Hg, P = .42). ARE had higher 30-day mortality (5 [7%] vs 48 [2%], P = .014); however, no difference was found in elective patients (2 of 65 [3%] vs 39 of 1898 [2%], P = .57). ConclusionsARE use has increased since commercial approval of VIV. The addition of ARE to AVR did not affect early safety in elective cases, and postoperative gradients were similar to those in patients not requiring ARE. Further studies are required to determine long-term outcomes after ARE, including VIV candidacy.

3-Year Outcomes of Balloon-Expandable Valves: 20-mm vs Larger Valves (≥23 mm)

BackgroundA prior Society of Thoracic Surgeons/American College of Cardiology TVT (Transcatheter Valve Therapy) Registry–based analysis reported similar 1-year clinical outcomes with small (20-mm) vs large (≥23-mm) balloon-expandable valves (BEV). ObjectivesThe aim of this study was to describe mid-term 3-year clinical outcomes for small vs large BEV and the relationship between discharge echocardiographic mean gradient (MG) and different definitions of prothesis-patient mismatch (PPM) with clinical outcomes. MethodsUsing the TVT Registry with Centers for Medicare and Medicaid Services linkage, a propensity-matched analysis of patients receiving 20- vs ≥23-mm BEVs was performed. Spline curves and Kaplan-Meier plots with adjusted HRs determined the relationship between MG and 3-year mortality. ResultsIn total, 316,091 patients were analyzed; after propensity matching, 8,100 pairs of each group were compared. The 20-mm BEV was associated with higher MGs compared with ≥23-mm BEVs (16.2 ± 7.2 mm Hg vs 11.8 ± 5.7 mm Hg; P < 0.0001). At 3 years, there was no difference in mortality between 20- and ≥23-mm BEVs (31.5% vs 32.5%, respectively; HR: 0.97; 95% CI: 0.90-1.05). Compared with an MG of 10 to 30 mm Hg, an MG <10 mm Hg (HR: 1.25; 95% CI:1.22-1.27) was associated with increased 3-year mortality. Measured severe PPM and predicted no PPM were associated with increased 3-year mortality (33.5% vs 32.9% vs 32.1%; P < 0.0001) and (33.5% vs 31.1% vs 30%; P < 0.0001), respectively. Low MG and severe measured PPM were associated with lower left ventricular ejection fraction (LVEF). ConclusionsPatients with small-prosthesis BEVs (20 mm) had identical 3-year survival as those with larger (≥23-mm) BEV valves. Severe measured PPM and low MG (<10 mm Hg), but not predicted severe PPM, were associated with lower LVEF and increased mortality, suggesting that LVEF is the culprit for worse outcomes.

Self-expandable transcatheter valve is a potentially useful option for a failing small surgical aortic bioprosthetic valve.

Trans-catheter aortic valve implantation inside a failing surgical aortic valve bio-prosthesis has become an alternative for patients at high risk for redo surgical aortic valve replacement. However, the correlation between the size of the failing surgical aortic valve and the occurrence of prosthesis-patient mismatch after trans-catheter implantation is still controversial. The aim of this study is to analyze and report the results in Japanese patients. Thirty patients who underwent trans-catheter aortic valve implantation inside a failing surgical aortic valve at our hospital were retrospectively reviewed with results from echocardiography and computed tomography. The patients' mean age was 84.5 ± 4.8years. The mean body surface area was 1.42 ± 0.13 m2. The cohort was divided into two groups according to the size of the failing bio-prosthesis: small (≦19mm) and large (> 19mm). There were no significant differences in mean pressure gradient (12.2 ± 4.0mmHg vs. 11.1 ± 1.2mmHg; p = 0.54) and effective orifice area index (1.00 ± 0.26cm2/m2 vs. 0.99 ± 0.25cm2/m2; p = 0.92) between the groups at 6months after trans-catheter implantation. The incidence of moderate (38.5% vs. 28.6%; p = 0.59) and severe (0% vs. 7.1%; p = 0.33) prosthesis-patient mismatch was equivalent. There was no significant difference in survival between the two groups (log-rank test p-value = 0.08). Trans-catheter implantation inside a failing small aortic valve did not increase the frequency of prosthesis-patient mismatch in this Japanese cohort.

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.

SEVERE SYMPTOMATIC MITRAL REGURGITATION AFTER ANNULOPLASTY FAILURE: SUCCESSFUL TRANSCATHETER EDGE TO EDGE REPAIR

Abstract Surgical mitral valve repair is the most common, feasible and preferred procedure to treat primary and secondary mitral regurgitation (MR). However, 30% of patients suffer from residue severe regurgitation 10 years after surgical intervention, resulting in a considerable number of Redo procedures. In elderly and high–risk patients with major comorbidities medical treatment is the only and often insufficient option for symptoms’ relief. Percutaneous Transcatheter Edge to Edge repair technique (TEER) with MitraClip system is emerging as an off–label valid alternative to successfully treat severe mitral regurgitation after surgical valvuloplasty failure. Transesophageal echocardiography (TEE) is essential in diagnosis, planning, intraprocedural device placement, and follow up. In the peculiar setting of failed annuloplasty, with small residual valve area, the main risk is the creation of a gradient across the mitral valve. We present two cases of severe mitral regurgitation after surgical annuloplasty with ring placement, carefully evaluated for TEER and successfully treated with this procedure: 1) a 79–year–old man presented with exertional dyspnea and orthopnea in the setting of previous surgical mitral Annuloplasty (2003) with a 32–mm Carpentier Ring. Transesophageal echocardiography demonstrated severe mitral regurgitation due to P2 prolapse and central V–shaped cut of the valve, mean diastolic gradient 1.8 mmHg. 2) a 83 year–old woman presented with dyspnea (NYHA functional class III) and severe mitral regurgitation after previous Annuloplasty with a 34–mm Edwards Ring and placement of Goretex artificial Chordae (2016). TEE showed prolapse of P2 and P3 leaflets, mean diastolic gradient 2.17 mmHg, valvular area 3.5 cmq. Both patients underwent transfemoral and transseptal implantation of one MitraClip device (XTw and XT, respectively) under Transesophageal echocardiography guidance with successful reduction of mitral regurgitation to mild level and symptoms relief. In the first case post procedural mean diastolic gradient was 3.7 mmHg, in the second case it was 3.16 mmHg.

VERY MOBILE LEFT VENTRICULAR PAPILLARY FIBROELASTOMA PRESENTING WITH ISCHEMIC STROKE

Abstract Papillary fibroelastomas are small and pedunculated left side valves associated mass, that frequently causing cerebral embolization; they are composed of collagen and elastic fibers and are usually connected with a pedicle to the endocardial layer. Differential diagnosis with endocarditis can rely on the side of attachement: Papillary fibroelastomas are more frequently found downstream the valves, instead, endocarditis are mostly found upstream the valves. They are mostly located (&amp;gt;80%) on valvular surfaces, more commonly on left side cardiac valves (44% on the aortic valve and 35% on the mitral valve); therefore, in the present knowledge, papillary fibroelastomas arising from left ventricular myiocardial wall are rare and mostly anecdotally descripted. We present the case of a 78–year–old man, diabetic, with no cardiac history, hospitalized with a right capsulo–lenticular stroke. Symptomatic due to left hemiparesis, he did not undergo thrombolysis due to a delay in hospitalization of almost 24 hours. The transthoracic and then transesophageal echocardiogram showed the presence of a hyperechogenic, floating mass of approximately 3 cm at the level of the left ventricle, separate from the mitral valve and attached to the mid–distal anterior septum and the ventricular apex (Figure 1). Cardiac MRI confirmed the presence of a peduncolate left ventricular mass, isointense on cine sequences, without myocardial infiltration, isointense on T1–weighted images and mildy hyperintense on T2–weighted images, with mild uniform late–gadolinium enhancement (Figure 2). The patient underwent surgical removal of the mass: histological analysis showed multiple, branching fronds of paucicellular, avascular fibroelastic tissue lined by a single layer of endocardium, with positive stains at Weigert coloration for elastic fibers (Figure 3). Histomorphological analysis was compatible with papillary fibroelastoma. This is a very atypical case of papillary fibroelastoma, due to the large size of the mass and the intraventricular and not–valvular location, which determined its emboligenicity and which, if not removed, would have exposed the patient to an enormous risk of recurrence of stroke.

Length control of a McKibben pneumatic actuator using a dynamic quantizer

McKibben pneumatic actuators (MPAs) are soft actuators that exert tension by applying compressed air to expand a rubber tube. Although electro-pneumatic regulators can control air pressure, most are large and expensive. This study utilizes a dynamic quantizer to control the MPA with a small solenoid valve that can only open and close the valve instead of an electro-pneumatic regulator. A dynamic quantizer is one of the quantizers that converts continuous signals to discrete signals. Our previous study confirmed that tension control of MPA under isometric conditions could be realized using a dynamic quantizer. However, it is often necessary to control the length of the MPA as well as the tension of the MPA. This study implements a dynamic quantizer to control the length of the MPA with a small solenoid valve. Numerical simulations and experimental tests verify the effectiveness of the proposed method. The results of the numerical simulations and experimental tests confirmed that the length of the MPA can be controlled using the dynamic quantizer.

Improved DBO-VMD and optimized DBN-ELM based fault diagnosis for control valve

Control valves play a vital role in process production. In practical applications, control valves are prone to blockage and leakage faults. At the small control valve openings, the vibration signals exhibit the drawbacks of significant interference and weak fault characteristics, which causes subpar fault diagnosis performance. To address the issue, a diagnostic model based on optimized variational mode decomposition (VMD) and improved deep belief network-extreme learning machine (DBN-ELM) is proposed. Firstly, good point set population initialization, nonlinear convergence factor, and adaptive Gaussian–Cauchy mutation strategies are applied in the dung beetle optimization algorithm (DBO) to escape local optima. Then, the improved DBO (IDBO) is used to optimize VMD parameters to obtain a series of modal components. Next, the generalized dispersion entropy (GDE) is formed by the combination of generalized Gaussian distribution and refined composite multiscale fluctuation-based dispersion entropy. The maximum correlation coefficient modal components are applied to extract GDE. Finally, the IDBO is applied to optimize the parameters of the DBN-ELM network to improve the classification performance of control valve faults. The comparative experiment results demonstrate that the proposed model can extract effective features and the diagnostic accuracy reaches 99.87%.

Risk of infective endocarditis after hybrid melody mitral valve replacement in infants: the French experience.

Surgical management of mitral valve disease is challenging in infants <1 year old. We aimed at reviewing the French experience with Melody mitral valve replacement in critically ill infants. A retrospective cohort study reporting the French experience with Melody mitral valve replacement. Seven symptomatic infants [complete atrioventricular septal defect (n = 4, Down syndrome: n = 3), hammock valve (n = 3)] underwent Melody mitral valve replacement [age: 3 months (28 days to 8 months), weight: 4.3 kg (3.2-6.4 kg)] because of severe mitral valve regurgitation (6) or mixed valve disease (1) and 14 mm (11-16 mm) mitral valve annulus. In 2 patients whose valve was felt irreparable, Melody mitral valve replacement was performed straightaway. The others underwent 2 (1-3) previous attempts of valve repair; 3 were on extracorporeal membrane oxygenation. Melody mitral valve replacement led to competent valve and low gradient [3 mmHg, (1-4 mmHg)]. One patient died 3 days post-implant from extracorporeal membrane oxygenation-related stroke. Of the 6 discharged home patients, 3 (50%) were readmitted for a definite diagnosis (1) or high suspicion (2) of infective endocarditis, of which 2 died. Over the follow-up, 1 underwent balloon expansions of the valve at 9- and 16-months post-implant, and mechanical mitral valve replacement at 2 years; another is currently planned for transcatheter Melody valve dilation. Melody mitral valve replacement may be considered in selected infants with small mitral valve annulus as an alternative to mechanical mitral valve replacement. Our experience highlights a high-risk of late infective endocarditis that deserves further consideration.

A new species of genus Crenotia (Bacillariophyta) from Tibet, China.

During the investigation of the freshwater diatoms from Tibet, a monoraphid species was observed from a hot spring near Anduo County, located on a plateau in the central portion of Tibet. This species shares the diagnostic features of Crenotia, such as the valve bent along the transapical axis, striae uniseriate to biseriate from centre to the apices and areolae with special structures located at the end of each stria. We compared the morphological characters of this new species with the others in this genus and show it to be new; it is named Crenotiatibetiasp. nov. This species has small valves with slightly protracted ends with nearly capitate apices, lanceolate axial area, central area unilaterally expanded to the margin, striae uniseriate to biseriate, but, in some valves, the striae are only uniseriate. Areolae are round small to irregular in shape and, at the end of each stria, there is a horseshoe-shaped areola present. Observations of developing valves show all the striae begin biseriate, then they become covered by silica to form uniseriate striae. Comparisons are made amongst the species in this genus and with genera assigned to the Achnanthidiaceae.

Tricuspid regurgitation burden following transcatheter aortic valve replacement requiring early pacemaker implantation

Background Conduction abnormality requiring the implantation of a permanent pacemaker (PPM) is a well-known and clinically important complication of transcatheter aortic valve replacement (TAVR). However, PPM implantation may result in lead-associated tricuspid valve regurgitation (TR). This study sought to determine the incidence and progression of TR following PPM implantation after TAVR. Methods This was a retrospective review of all echocardiograms of patients who underwent PPM following TAVR at the Baylor Scott & White hospitals from 2012 to 2021. The primary endpoint was TR progression at 30 days and 1 year. A subanalysis comparing the change in TR progression between small and large TAVR devices was also conducted. Secondary outcomes included all-cause death at 30 days and 1 year. Results Out of the 2744 patients who underwent TAVR between April 2012 and August 2021, 177 patients (6.5%) subsequently received a new PPM. There was a statistically significant progression of TR at 1-year follow-up (McNemar’s P value = 0.02). TR progression rates were comparable between the small and large valve groups at 1-year follow-up (4% vs 11%, P = 0.09, respectively). Conclusion In this single healthcare system study, we demonstrated a significant progression of TR in patients with PPM post TAVR at 1 year.

Early and Mid-Term Outcomes of Using the Chimney Technique in Redo Mitral Valve Replacement in Patients with a Small Mitral Annulus.

The outcomes of redo mitral valve replacement (Re-MVR) in a small mitral annulus with the use of the chimney technique are not well documented. The purpose of this study is to present our early experience with this group of patients, illustrating the periop-erative complications and mortality outcomes. From 2019 to 2020, 77 consecutive patients underwent Re-MVR with the use of the chimney technique because of a small mitral annulus. To evaluate heart structural integrity and clinical outcomes, postoperative clinical data and echocardiograms were examined. The mean age was 56.7 ± 15.98 years. All patients underwent mitral valve surgery, of which 62 were mitral valve replacements, 7 mitral valve repairs, and 8 double valve replacements. The preoperative mitral valve mean gradient was 18.07 ± 9.40 mmHg, and the postoperative mitral prosthesis size was 28.51 ± 1.22 mm. The median increment of mitral size enlargement was 4 (0, 6) valve sizes. The mean mitral gradient coming out of the operating room was 10.34 ± 2.12 mmHg, and at the follow-up echocardiogram performed at 3 years after the procedure, it was 10.36 ± 1.70 mmHg. One-year survival was 93.3%, while the 4-year survival rate was 89.3%, with no reoperation. The use of the chimney technique in small mitral valve re-mitral valve replacement results in larger valve sizes. Moreover, the mean gradients over the mitral valve are acceptable both intraoperatively and over time.