Valve Morphology Research Articles

Characteristics and outcomes of the Spanish registry for pediatric patients with bicuspid aortic valve (REVAB)

Introduction and objectivesBicuspid aortic valve (BAV) disorder is the most common congenital heart disease. The aim of this study was to describe the characteristics of 0- to 18-year olds with BAV in a population-based registry. MethodsData from all pediatric patients were obtained from the Spanish registry for pediatric patients with bicuspid aortic valve (REVAB) (< 18 years). For data analysis, patients with BAV were divided into 2 groups by their features: isolated BAV and BAV with associated congenital heart disease. ResultsWe included 1681 patients from 33 hospitals. Males accounted for 69.6% (n = 1158). Valve morphology was horizontal in 63.4% (n = 1012) and pure (Sievers type 0) in 28.4% (n=469). Isolated BAV was present in 63.7% (n=1060), and concomitant left-sided obstructive lesions in 23.4% (n=390). Interventions were required in 8.6% (n=145). ConclusionThese data represent the first large, population-based description of the clinical presentations and outcomes of patients enrolled in the Spanish registry for pediatric patients with bicuspid aortic valve.

Arthroscopic cystectomy and valve excision of popliteal cysts complemented with management of intra-articular pathologies: a low recurrence rate and good functional outcomes in a series of ninety seven cases

PurposeArthroscopy in popliteal cyst surgery enables addressing all components of its pathomechanism: the cyst wall, valvular mechanism, and concomitant intra-articular pathologies. Techniques differ as to the management of the cyst wall and the valvular mechanism. This study aimed to assess the recurrence rate and functional outcomes of a cyst wall and valve excising arthroscopic technique with concurrent intra-articular pathology management. The secondary purpose was to assess cyst and valve morphology and concomitant intra-articular findings.MethodsBetween 2006 and 2012, 118 patients with symptomatic popliteal cysts refractory to at least three months of guided physiotherapy were operated on by a single surgeon using a cyst wall and valve excising arthroscopic technique with intra-articular pathology management. Patients were evaluated preoperatively and at a mean follow-up of 39 months (range 12–71) by ultrasound, Rauschning and Lindgren, Lysholm, and VAS of perceived satisfaction scales.ResultsNinety-seven out of 118 cases were available for follow-up. Recurrence was observed on ultrasound in 12/97 cases (12.4%); however, it was symptomatic only in 2/97 cases (2.1%). Mean scores improved: Rauschning and Lindgren from 2.2 to 0.4, Lysholm from 54 to 86, and VAS of perceived satisfaction from 5.0 to 9.0. No persistent complications occurred. Arthroscopy revealed simple cyst morphology in 72/97 (74.2%) and presence of a valvular mechanism in all cases. The most prevalent intra-articular pathologies were medial meniscus (48.5%) and chondral lesions (33.0%). There were significantly more recurrences in grade III–IV chondral lesions (p = 0.03).ConclusionsArthroscopic popliteal cyst treatment had a low recurrence rate and good functional outcomes. Severe chondral lesions increase the risk of cyst recurrence.

Comparative Morphological and Morphometrical Analysis of Atrio-Ventricular Valves of Human and Porcine

There is increased incidence of valvular heart diseases in recent years due to life style modifications. The mortality rates in valvular diseases are kept in pace using various modalities of treatments. One such lifesaving treatment is valve replacement surgeries. These are done by using mechanical valve prosthesis or tissue grafts. The tissue valves prosthesis, harvested from porcine heart are called as xenograft and are increasingly used in valve repair and replacement surgeries. In the present scenario, there is a smaller number of systematically analysed literatures available on the comparative anatomy of human and porcine heart valves. Hence this study was carried out to acquire knowledge and to put forth some points to future research works on heart valves. In this study, 20 formalin fixed porcine and human hearts were procured from slaughter house and cadavers respectively. The morphology and morphometry of tricuspid valve and mitral valve was observed and analysed using spss software 20 version. All the dependent variables were compared using student t test and independent sample test. The results were tabulated and compared. It was observed that the tricuspid and the mitral valve of the porcine resembles the corresponding human heart valves in morphology and morphometry and their values were coinciding to their maximum. The porcine valve resembles human heart valves in morphology and it can be used in designing valve substitutes in replacement surgeries. Porcine valve can also be used as bio-prosthesis by matching the morphometry and by reducing the geometrical difference to their minimum by using any interventional radiology. KEY WORDS: Tissue Graft, Porcine, Tricuspid Valve, Mitral Valve, Morphology And Morphometry.

Calcific aortic valve disease: mechanisms, prevention and treatment.

Calcific aortic valve disease (CAVD) is the most common disorder affecting heart valves and is characterized by thickening, fibrosis and mineralization of the aortic valve leaflets. Analyses of surgically explanted aortic valve leaflets have shown that dystrophic mineralization and osteogenic transition of valve interstitial cells co-occur with neovascularization, microhaemorrhage and abnormal production of extracellular matrix. Age and congenital bicuspid aortic valve morphology are important and unalterable risk factors for CAVD, whereas additional risk is conferred by elevated blood pressure and plasma lipoprotein(a) levels and the presence of obesity and diabetes mellitus, which are modifiable factors. Genetic and molecular studies have identified that the NOTCH, WNT-β-catenin and myocardin signalling pathways are involved in the control and commitment of valvular cells to a fibrocalcific lineage. Complex interactions between valve endothelial and interstitial cells and immune cells promote the remodelling of aortic valve leaflets and the development of CAVD. Although no medical therapy is effective for reducing or preventing the progression of CAVD, studies have started to identify actionable targets.

Endoscopic evaluation technique using a camera port for valve-sparing root reconstruction.

Intraoperative aortic valve evaluation should be accurate in valve-sparing root replacement to minimize postoperative aortic valve regurgitation. Ascending aorta de-clamping and weaning of cardiopulmonary bypass are required in intraoperative transoesophageal echocardiography. Aortic valve endoscopy aids in the magnification of structures and enables image sharing within the operative team. While a rigid endoscope and saline infusion line are directly inserted from the Valsalva graft end, a Kelly clamp is needed for graft gap closure, affecting the valve morphology due to graft deformation. The accurate inner pressure of the neo-Valsalva sinus cannot be measured in this method. We propose a technique to accurately evaluate aortic valve conformation using a balloon blunt-tip system that enables aortic valve evaluation under the measured pressure and without Valsalva graft deformation.

Influence of aortic valve morphology on vortical structures and wall shear stress.

The aim of this paper is to assess the association between valve morphology and vortical structures quantitatively and to highlight the influence of valve morphology/orientation on aorta's susceptibility to shear stress, both proximal and distal. Four-dimensional phase-contrast magnetic resonance imaging (4D PCMRI) data of 6 subjects, 3 with tricuspid aortic valve (TAV) and 3 with functionally bicuspid aortic values (BAV) with right-left coronary leaflet fusion, were processed and analyzed for vorticity and wall shear stress trends. Computational fluid dynamics (CFD) has been used with moving TAV and BAV valve designs in patient-specific aortae to compare with in vivo shear stress data. Vorticity from 4D PCMRI data about the aortic centerline demonstrated that TAVs had a higher number of vortical flow structures than BAVs at peak systole. Coalescing of flow structures was shown to be possible in the arch region of all subjects. Wall shear stress (WSS) distribution from CFD results at the aortic root is predominantly symmetric for TAVs but highly asymmetric for BAVs with the region opposite the raphe (fusion location of underdeveloped leaflets) being subjected to higher WSS. Asymmetry in the size and number of leaflets in BAVs and TAVs significantly influence vortical structures and WSS in the proximal aorta for all valve types and distal aorta for certain valve orientations of BAV. Analysis of vortical structures using 4D PCMRI data (on the left side) and wall shear stress data using CFD (on the right side).

Cavitation state recognition for control valve using AlexNet-type neural networks with three-channel images transformed by time series

The control valve is a crucial component with high switching frequency in coal liquefaction systems. Its performance exerts a great influence on the long-term operations in the coal chemical technology. Cavitation is a key factor affecting the control accuracy and surface morphology of the control valve; hence, it will further shorten the service life of the control valve. A cavitation state recognition model based on vibration acceleration time series is proposed in this paper, and the cavitation stage in the valve is identified accurately. Three vibration acceleration sensors are attached to the valve seat to measure cavitation-induced vibration data. The collected time series is divided into fragments based on the non-overlap moving window method, and these fragments are converted into feature maps using the Gramian angular field transform. These feature maps are then input into AlexNet to train the cavitation state recognition model. The experimental results show that recognition accuracy could be improved effectively upon the increase in the length of the time series fragment, and the proposed model has a similar prediction accuracy on unfamiliar datasets. Compared with no noise, the recognition accuracy could reach to 95% when the moving window length is 150 and the signal-to-noise ratio is equal to 5 dB. Furthermore, the proposed model could still achieve good recognition results under mixed open conditions.

Aortic Stenosis: Haemodynamic Benchmark and Metric Reliability Study

Aortic stenosis is a condition which is fatal if left untreated. Novel quantitative imaging techniques which better characterise transvalvular pressure drops are being developed but require refinement and validation. A customisable and cost-effective workbench valve phantom circuit capable of replicating valve mechanics and pathology was created. The reproducibility and relationship of differing haemodynamic metrics were assessed from ground truth pressure data alongside imaging compatibility. The phantom met the requirements to capture ground truth pressure data alongside ultrasound and magnetic resonance image compatibility. The reproducibility was successfully tested. The robustness of three different pressure drop metrics was assessed: whilst the peak and net pressure drops provide a robust assessment of the stenotic burden in our phantom, the peak-to-peak pressure drop is a metric that is confounded by non-valvular factors such as wave reflection. The peak-to-peak pressure drop is a metric that should be reconsidered in clinical practice.Graphical abstractThe left panel shows manufacture of low cost, functional valves. The central section demonstrates circuit layout, representative MRI and US images alongside gross valve morphologies. The right panel shows the different pressure drop metrics that were assessed for reproducibility

Improved image quality in transcatheter aortic valve implantation planning CT using deep learning-based image reconstruction.

This study aims to evaluate the impact of a novel deep learning-based image reconstruction (DLIR) algorithm on the image quality in computed tomographic angiography (CTA) for pre-interventional planning of transcatheter aortic valve implantation (TAVI). We analyzed 50 consecutive patients (median age 80 years, 25 men) who underwent TAVI planning CT on a 256-dectector-row CT. Images were reconstructed with adaptive statistical iterative reconstruction V (ASIR-V) and DLIR. Intravascular image noise, edge sharpness, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were quantified for ascending aorta, descending aorta, abdominal aorta and iliac arteries. Two readers (one radiologist and one interventional cardiologist) scored task-specific subjective image quality on a five-point scale. DLIR significantly reduced median image noise by 29-57% at all anatomical locations (all P<0.001). Accordingly, median SNR improved by 44-133% (all P<0.001) and median CNR improved by 44-125% (all P<0.001). DLIR significantly improved subjective image quality for all four pre-specified TAVI-specific tasks (measuring the annulus, assessing valve morphology and calcifications, the coronary ostia, and the suitability of the aorto-iliac access route) for both the radiologist and the interventional cardiologist (P≤0.001). Measurements of the aortic annulus circumference, area and diameter did not differ between ASIR-V and DLIR reconstructions (all P>0.05). DLIR significantly improves objective and subjective image quality in TAVI planning CT compared to a state-of-the-art iterative reconstruction without affecting measurements of the aortic annulus. This may provide an opportunity for further reductions in contrast medium volume in this population.

Erosion microscopic morphology and formation mechanism of hydraulic servo spool valve

This study investigates the microscopic morphology of a hydraulic servo spool valve caused by particle erosion. The microscopic morphology of spool working edges and solid particle characteristics in oil of a typical hydraulic servo system were experimentally studied. The formation mechanism was analyzed using dynamic impact calculation. The results reveal that the erosion micro-morphology of the spool working edge was mainly characterized by surface peeling, notches, grooves, and chamfers. The contour of the working edge was rounded. The average and variance of the radius of the old spool’s working edges were obviously higher than those of the new spool. The main distribution range of solid particle size in typical servo-hydraulic system oil was 5–50 μm, and the number of particles decreased sharply with an increase in particle size, up to 90.89%. The actual shape of particles was close to an ellipsoid with strong erosion destructive power. When a single solid particle collided with the working edge, a large amount of stress was generated at the collision center point, and the stress can reach 1500 MPa when the pressure differential at the valve orifice was 3.5 MPa. The working edges were subjected to cyclic stress of high-frequency particle pulses, resulting in fatigue erosion.

Clinical and Echocardiographic Features of Patients With Infective Endocarditis and Bicuspid Aortic Valve According to Echocardiographic Definition of Valve Morphology

The influence of different bicuspid aortic valve (BAV) morphology in the clinical course of infective endocarditis (IE) has not yet been investigated. This study aimed to describe the clinical and echocardiographic features of IE in patients with BAV (BAVIE) according to valve morphology. Patients with definite BAVIE prospectively enrolled in 4 high-volume referral centers from 2000 to 2019 were evaluated and divided into 2 groups according to the echocardiographic definition of fused BAV morphology: right-left coronary (RL type) and right noncoronary or left noncoronary (non-RL type) cusp fusion. All patients were followed up for 1year. One hundred thirty-eight patients with BAVIE were included (77.7% male; median age, 52 [36.83-61.00]years): 112 patients with RL type (81%) and 26 patients with non-RL type BAV (19%), with no significant differences in age, sex, and comorbidities between groups. Although 43% of the cohort had known BAV, the referral was late after symptom onset, particularly for the RL phenotype; time from symptom onset to hospitalization >30days (31.3% vs 11.5%; P=.032) and New York Heart Association class≥II (64.3% vs 42.3%; P=.039) were more frequent in patients with RL type BAV than in patients with non-RL type BAV. Conversely, patients with non-RL type BAV had a higher incidence of hemorrhagic stroke (19.2% vs 5.4%; P=.034) and high-grade atrioventricular block (11.5% vs 0.9%; P=.021). Streptococcus viridans was more frequently isolated in patients with non-RL type BAV than in patients with RL type BAV (44% vs 24.1%; P=.045). No difference in short- and intermediate-term mortality was observed between groups. Clinical profile and echocardiographic features in BAVIE patients may differ according to valve morphology, and patients with BAVIE appear to be referred late, even when BAV disease is previously known.

Differences in aortic valve area measured on cardiac CT and echocardiography in patients with aortic stenosis.

A certain proportion of patients with severe aortic stenosis (AS) present with discordant grading between different diagnostic modalities, which raises uncertainty about the true severity of AS. The aim of this study was to compare the aortic valve area (AVA) measured on CT and echocardiography and demonstrate the factors affecting AVA discrepancies. Between June 2011 and March 2016, 535 consecutive patients (66.83±8.80 years, 297 men) with AS who underwent pre-operative cardiac CT and echocardiography for aortic valve replacement were retrospectively included. AVA was obtained by AVA on echocardiography (AVAecho) and CT (AVACT) using a measurement of the left ventricular outflow tract on each modality and correlations between those measures were evaluated. Logistic regression analysis was performed to identify factors affecting the discordance for grading severe AS. The AVACT and AVAecho showed a high correlation (r: 0.79, P <0.001) but AVACT was larger than the AVAecho (difference 0.26 cm2, P <0.001). By using the cut-off values of AVACT (<1.2 cm2) and AVAecho (<1.0 cm2) for diagnosing severe AS, the BSA (odds ratio [OR]: 68.03, 95% confidence interval [CI]: 5.45-849.99; P = 0.001), AVAecho (OR: 1.19, 95%CI: 1.14-1.24; P <0.001), tricuspid valve morphology (OR: 2.83, 95%CI: 1.23-6.50; P = 0.01), and normalized annulus area (OR: 1.02; 95%CI:1.02-1.03; P <0.001) were significant factors associated with the discordance between the AVAecho and AVACT. Patients with larger BSA, AVAecho, and annulus, and tricuspid valve morphology were associated with the AVA discordance between the echocardiography and CT. Complementary use of CT with echocardiography for grading severe AS could be helpful in such conditions.

Two and three-dimensional transesophageal echocardiography for pre-operative assessment of mitral valve morphology and regurgitation severity

Background: Two-dimensional (2D) transthoracic (TTE) and transesophageal echocardiography (TEE) are the two main diagnostic modalities used to assess valvular heart diseases, particularly for mitral valve injury. In patients who have the indication of mitral valve surgery, 2D TEE &amp; TTE have some limitations in identifying valve lesions. Three-dimensional transesophageal echocardiography (3D TEE) is more accurate than 2DTTE and 2DTEE in the qualitative assessment of mitral valve.&#x0D; Objectives. Evaluating valve morphology and the severity of mitral valve regurgitation using 2DTTE and 2D/3D TEE in patients who required surgical intervention, compared to surgical and left ventricular angiography findings. Subjects: 44 patients with surgical indication from September 2017 to June 2018 were enrolled in this study.&#x0D; Methods: A cross-sectional study conducted at Vietnam National Heart Institute from September 2017 to June 2018. 44 patients with mitral regurgitation who had indication for mitral valve surgery underwent 2D TEE and 2D/3D TEE before opened heart surgery for mitral valve, 17/44 had left ventriculogram during coronary angiogram before surgery.&#x0D; Results: Men/women ratio = 2/1. Mean age: 54.14 ± 13.066 years old. Most of patients (93,2%) had symptoms of heart failure with mean NYHA classification of 2.55 ± 0.504. 3D TEE showed higher diagnostic accuracy and better agreement with surgical findings compared to 2D TEE and 2D TTE in A2 prolapse, A3 prolapse, P3 prolapse, Kappa =1,1,0.65 respectively. For anterior leaflet perforation, 3D TEE had positive predictive value of 100% and better agreement (Kappa =1) in comparison with 2D TEE and 2D TTE with positive predictive value of 96,5 %, Kappa = 0,65. In identifying valve vegetation, 3D TEE had positive predictive value of 93%, kappa =0,82 which were higher than those of 2D TEE and 2D TTE (positive predictive value of 89,6 % and Kappa = 0,73). In evaluating mitral valve regurgitation, 3D TEE had positive predictive value of 100%, kappa =1 compared with positive predictive value of 76,5%, kappa of 0,47 of 2D TEE and 2D TTE. Conclusions: 3D TEE is valuable in localizing prolapse valve segments, especially for A2, A3 and P3 prolapse, as well as in diagnosing anterior leaflet perforation and vegetation of mitral valve. 3D TEE is also more valuable than 2D TEE and 2D TTE in assessing mitral regurgitation severity.

Characteristics and outcomes of patients undergoing transcatheter mitral valve replacement with the Tendyne system

BackgroundTranscatheter mitral valve replacement (TMVR) has emerged as alternative to transcatheter edge-to-edge repair (TEER) for treatment of mitral regurgitation (MR); however, the role of TMVR with the Tendyne system among established treatments of MR is not well defined. We assessed characteristics and outcomes of patients treated with the Tendyne system in the current clinical practice.MethodsWe reviewed patients who underwent cardiac computed tomography and were judged eligible for the Tendyne system.ResultsA total of 63 patients were eligible for TMVR with the Tendyne system. Of these, 17 patients underwent TMVR, and 46 were treated by TEER. Patients treated with the Tendyne system were more likely to have a high transmitral pressure gradient and unsuitable mitral valve morphology for TEER than those treated with TEER. TMVR with the Tendyne system reduced the severity of MR to less than 1 + in 94.1% of the patients at discharge and achieved a greater reduction in left ventricular (LV) end-diastolic volume at the 30-day follow-up compared with TEER. In contrast, patients treated with the Tendyne system had a higher 30-day mortality than those treated with TEER, while the mortality between 30 days and one year was comparable between Tendyne and TEER.ConclusionsAmong patients eligible for the Tendyne system, approximately a quarter of the patients underwent TMVR with the Tendyne system, which led substantial reduction of MR and LV reverse remodeling than TEER. In contrast, the 30-day mortality rate was higher after TMVR with the Tendyne compared to TEER.

Anatomical morphology of the aortic valve in Chinese aortic stenosis patients and clinical results after downsize strategy of transcatheter aortic valve replacement.

The study aimed to describe the aortic valve morphology in Chinese patients underwent transcatheter aortic valve replacement (TAVR) for symptomatic severe aortic stenosis (AS), and the impact of sizing strategies and related procedural outcomes. Patients with severe AS who underwent TAVR were consecutively enrolled from 2012 to 2019. The anatomy and morphology of the aortic root were assessed. "Downsize" strategy was preformed when patients had complex morphology. The clinical outcomes of patients who performed downsize strategy were compared with those received annular sizing strategy. The primary outcome was device success rate, and secondary outcomes included Valve Academic Research Consortium-3 clinical outcomes variables based on 1-year follow-up. A total of 293 patients were enrolled. Among them, 95 patients (32.4%) had bicuspid aortic valve. The calcium volume (Hounsfield Unit-850) of aortic root was 449.90 (243.15-782.15) mm 3 . Calcium is distributed mostly on the leaflet level. Downsize strategy was performed in 204 patients (69.6%). Compared with the patients who performed annular sizing strategy, those received downsize strategy achieved a similar device success rate (82.0% [73] vs . 83.3% [170], P = 0.79). Aortic valve gradients (downsize strategy group vs . annular sizing group, 11.28 mmHg vs. 11.88 mmHg, P = 0.64) and percentages of patients with moderate or severe paravalvular regurgitation 2.0% (4/204) vs . 4.5% (4/89), P = 0.21) were similar in the two groups at 30 days after TAVR. These echocardiographic results were sustainable for one year. Chinese TAVR patients have more prevalent bicuspid morphology and large calcium volume of aortic root. Calcium is distributed mostly on the leaflet level. Compare with annular sizing strategy, downsize strategy provided a non-inferior device success rate and transcatheter heart valve hemodynamic performance in self-expanding TAVR procedure.

3D echocardiography in mitral valve prolapse.

Mitral valve prolapse (MVP) is the leading cause of mitral valve surgery. Echocardiography is the principal imaging modality used to diagnose MVP, assess the mitral valve morphology and mitral annulus dynamics, and quantify mitral regurgitation. Three-dimensional (3D) echocardiographic (3DE) imaging represents a consistent innovation in cardiovascular ultrasound in the last decades, and it has been implemented in routine clinical practice for the evaluation of mitral valve diseases. The focus of this review is the role and the advantages of 3DE in the comprehensive evaluation of MVP, intraoperative and intraprocedural monitoring.

Aortic valve morphology and paravalvular leak regression after a self-expandable transcatheter aortic valve replacement.

Aims: The study aimed to compare paravalvular leak (PVL) changes after a transcatheter aortic valve replacement (TAVR) with self-expandable prosthesis between different aortic valve morphologies and evaluate the impact of paravalvular leak regression on clinical prognosis. Methods: Patients with aortic stenosis (AS) successfully treated with a self-expandable TAVR who were followed up for at least 1year at our centre were consecutively enrolled from January 2016 to August 2019. Paired serial changes in paravalvular leak and other haemodynamic parameters by echocardiography were collected and compared between the bicuspid valve (BAV) and tricuspid aortic valve (TAV). A logistic regression model was used to explore the predictors of paravalvular leak regression (<1 grade) 1year after transcatheter aortic valve replacement, while its impact on subsequent clinical outcomes (all-cause mortality and rehospitalisation for heart failure (HF)) was further evaluated using Kaplan-Meier analysis. Results: A total of 153 bicuspid valve and 114 tricuspid aortic valve patients were finally enrolled; haemodynamic parameters and paravalvular leak severity were comparable before the discharge between the two groups. The peak transaortic velocity, mean transvalvular gradient, and effective orifice area all significantly improved (p < 0.05) without intergroup differences at all follow-up timepoints. Significant paravalvular leak reduction was observed only in the TAV group (1.75% vs. 4.39%, p = 0.029), while moderate paravalular leak was still more prevalent in BAV (7.19% vs. 1.75%, p = 0.041) at the 1-year follow-up. Multivariable analyses identified the bicuspid valve, asymmetric calcification, and undersizing as independent predictors of failure of the 1-year paravalvular leak reduction in patients with mild or moderate paravalvular leak after discharge. Patients without a paravalvular leak reduction within 1 year showed a relatively higher 2-year all-cause mortality and HF (HR: 5.994, 95% CI: 1.691-21.240, and p = 0.053) rates thereafter. Conclusion: In AS patients after self-expandable transcatheter aortic valve replacement, paravalvular leak regression within 1year was less prevalent in bicuspid valve morphology. The failure of paravalvular leak reduction might lead to an increased risk of poorer prognosis in the long run.

On the enigmatic diatom Rhizosolenia dubia, its relationship to Pseudopyxilla and Proboscia, and description of a new species, Proboscia pinocchioi sp. nov.

Pyxilla? dubia was originally described from Jutland, but subsequently transferred to Pseudopyxilla. However, the discovery, over eighty years apart, of two enigmatic specimens with tubular heterovalvate frustules featuring a Pseudopyxilla dubia valve at one end and a rhizosolenioid valve at the other end resulted in a new combination, Rhizosolenia dubia. Herein, we document in detail the valve morphology of specimens observed in early Eocene samples from Mors (Jutland) using light and scanning electron microscopy. Our results reveal the presence of both valve types (but never as heterovalvate frustules). The rhizosolenioid valves possess a proboscis with three spinulae at the tip (the middle one being very extensive), a longitudinal slit on the dorsal side, and claspers on the basal part of the domed valve on the ventral side. Our results suggest that the Pseudopyxilla frustule is the resting spore of a yet, unknown diatom, while the ‘rhizosolenioid’ valve represents the vegetative phase of a new species, Proboscia pinocchioi sp. nov. From an evolutionary standpoint, P. pinocchioi lacks the longitudinal ridges of the cretacea lineage, but bears the characteristic polar spinulae and limited pore distribution of the barboi lineage. However, P. pinocchioi surprisingly possesses claspers (normally observed only in the alata lineage) – representing the oldest evidence of claspers in rhizosolenioid diatoms.

In-silico modelling of the impact of hypertension on the mean transvalvular gradients in aortic stenosis.

The influence of hypertension on the diagnostic assessment of aortic stenosis (AS) severity is unclear, yet clinically relevant. To clarify the effect of hypertension on transvalvular gradients, requires a better understanding of the impact that blood pressure change has on mean flow rate. Also, the effect of various degrees of AS severity, the valve geometry and intrinsic left ventricular contractile function (elastance) on this interaction, needs to be clarified. The current work aims to assess this interaction and the magnitude of these effects. A validated, zero-dimensional electro-hydraulic analogue computer model of the human cardiovascular circulatory system was generated. It was used to assess the impact of blood pressure changes on left ventricular pressure and transvalvular gradients at various flow rates, left ventricular elastances, a range of aortic valve areas and for different aortic valve morphologies. The magnitude of the impact of hypertension induced changes on the mean gradient (MG) is influenced by the mean flow rate, the AS severity, the hydraulic effective valve orifice area and the left ventricular elastance. Generally, for a given change in systemic arterial pressure, the impact on MG will be the most marked for lower flow rate states such as is expected in more severe degrees of AS, for worse intrinsic left ventricular (LV) contractility, shorter ejection times and lower end diastolic LV volumes. Given the above conditions, the magnitude of the effect will be more for a larger aortic sinus diameter, and also for a typical degenerative valve morphology compared to a typical rheumatic valve morphology. The interaction between hypertension and mean gradients in AS is complex. The current work places previous recommendations in perspective by quantifying the magnitude of the effect that the changes in blood pressure has on mean gradient in various pathophysiological states. The work creates a framework for the parameters that should be considered in future clinical research on the topic.

Двустворчатый аортальный клапан у детей: современный взгляд на проблему

Bicuspid aortic valve (BAV) is a poorly studied aortic valve defect, occurring in the population with a frequency of 0.5–1 to 2–3%. Despite the absence of significant clinical manifestations in childhood, BAV can cause the development of serious complications in adult patients. Modern genetic studies confirm the hereditary nature of the disease, but are not used in routine diagnostic practice. The widespread use of echocardiography as a screening allows identifying the defect at the preclinical stage, but low awareness of doctors about the significant consequences of this defect often leads to the early development of complications, especially if the patient experiences regular intense physical activity with irregular follow-up of the valve condition. The lack of patient management algorithms stipulated by Russian regulatory documents makes it difficult to provide high-quality and timely care and increases the risk of complications. We analyzed Russian and foreign sources describing the features of embryogenesis and morphology of the bicuspid aortic valve, peculiarities of clinical manifestations of the malformation, modern approaches to diagnosis, including the possibility of genetic studies, as well as therapeutic and surgical methods of treatment of the malformation and its complications. The review also presents a new classification of congenital bicuspid aortic valve and related aortopathies.