A set of novel nonlinear variable structure excitation and steam-valving controllers are proposed in this paper. On the basis of the classical dynamic equations of a generator, excitation control and steam valving con...A set of novel nonlinear variable structure excitation and steam-valving controllers are proposed in this paper. On the basis of the classical dynamic equations of a generator, excitation control and steam valving control are simultaneously considered. Design of these controllers combines the differential geometry theory with the variable structure controlling theory. The mathematical model in the form of ＂an affine nonlinear system＂ is set up for the control design of a large-scale power plant. The dynamic performance of the nonlinear variable structure controllers proposed for a single machine connected to an infinite bus power system is simulated. Simulation results show that the nonlinear variable structure excitation and steam-valving controllers give satisfactory dynamic performance and good robustness.展开更多
A high-temperature and high-pressure valve is the key equipment of a wind tunnel system;it controls the generation of high-temperature and high-pressure gas.To reduce the adverse impact of high-temperature and high-pr...A high-temperature and high-pressure valve is the key equipment of a wind tunnel system;it controls the generation of high-temperature and high-pressure gas.To reduce the adverse impact of high-temperature and high-pressure gas on the strength of the valve body,a cooling structure is set on the valve seat.This can significantly reduce the temperature of the valve body and valve seat.The effects of its structure on the cooling characteristics and stress of the valve seat are studied,and six main parameters that can completely describe the geometry of the cooling structure are proposed.The central composite design method is used to select sample points,and the multi-objective genetic algorithm(MOGA)method is used for optimal structural design.A modification method according to the main parameters for the valve seat is proposed.The results show that the cooling structure weakens the pressure-bearing capability of the valve seat.Among the six main parameters of the valve seat,the distance from the end face of the lower hole to the Z-axis and the distance from the axis of the lower hole to the origin of the coordinates have the most obvious effects on the average stress of the valve seat.An optimum design value is proposed.This work can provide a reference for the design of high-temperature and high-pressure valves.展开更多
BACKGROUND The management of severe symptomatic aortic stenosis has been revolutionized by transcatheter aortic valve replacement(TAVR),offering a minimally invasive alternative to surgical aortic valve replacement(SA...BACKGROUND The management of severe symptomatic aortic stenosis has been revolutionized by transcatheter aortic valve replacement(TAVR),offering a minimally invasive alternative to surgical aortic valve replacement(SAVR).However,the compara-tive safety and efficacy of these interventions remain subjects of ongoing investigation.AIM To compare the clinical outcomes and safety of TAVR vs SAVR in patients with severe symptomatic aortic stenosis.METHODS A systematic review and meta-analysis were conducted according to PRISMA guidelines.Randomized controlled trials(RCTs)comparing TAVR and SAVR were identified from databases including PubMed,Scopus,and Web of Science up to May 31,2024.Data were extracted on clinical outcomes,including mortality,procedural compli-cations,and post-procedure adverse events.Risk ratios(RRs)with 95%CIs were calculated using a random-effects model.RESULTS A total of 10 RCTs were included.TAVR demonstrated a significantly lower risk of acute kidney injury(RR:0.33;95%CI:0.25–0.44),major bleeding(RR:0.37;95%CI:0.30–0.46),and new-onset atrial fibrillation(RR:0.44;95%CI:0.34–0.57)compared to SAVR.However,TAVR was associated with higher risks of new permanent pacemaker implantation(RR:3.49;95%CI:2.77–4.39),major vascular complications(RR:2.47;95%CI:1.91–3.21),and paraval-vular leaks(RR:4.15;95%CI:3.14–5.48).Mortality at 30 days was comparable(RR:0.95;95%CI:0.78–1.15),but long-term mortality was slightly higher with TAVR in some analyses(RR:1.23;95%CI:1.01–1.49).Rates of stroke(RR:0.97;95%CI:0.81–1.17)and myocardial infarction(RR:0.91;95%CI:0.67–1.24)were similar between the groups.CONCLUSION TAVR offers a less invasive option with significant benefits in reducing acute kidney injury,major bleeding,and new-onset atrial fibrillation,making it particularly advantageous for high-risk surgical candidates.However,higher risks of permanent pacemaker implantation,vascular complications,and paravalvular leaks highlight the need for individualized patient selection and shared decision-making to optimize outcomes.展开更多
Background There is scarce data about comparisons between geriatric assessment tools in patients with aortic stenosis(AS).We aimed to describe the geriatric profile of patients with AS undergoing transcatheter aortic ...Background There is scarce data about comparisons between geriatric assessment tools in patients with aortic stenosis(AS).We aimed to describe the geriatric profile of patients with AS undergoing transcatheter aortic valve implantation(TAVI)and to analyze the ability of different tools for predicting clinical outcomes in this context.Methods This was a single center retrospective registry including patients with AS undergoing TAVI and surviving to hospital discharge.The primary endpoint was all-cause mortality or need for urgent readmission one year after TAVI.Results A total of 377 patients were included(mean age of 80.4 years).Most patients were independent or mildly dependent,with an optimal cognitive status.The proportion of frailty ranged from 17.6%to 49.8%.A total of 20 patients(5.3%)died and 110/377 patients(29.2%)died or were readmitted during follow up.Overall,most components of the geriatric assessment showed an association with clinical outcomes.Disability for instrumental activities showed a significant association with mortality and a strong association with the rate of mortality or readmission.The association between frailty and clinical outcomes was higher for short physical performance battery(SPPB),essential frailty toolset(EFT)and the frailty index based on comprehensive geriatric assessment(IF-VIG)and lower for Fried criteria and FRAIL scale.Conclusions AS patients from this series presented a good physical performance,optimal cognitive status and a reasonably low prevalence of frailty.The best predictive ability was observed for disability for instrumental activities and frailty as measured by the EFT,SPPB and the IF-VIG.展开更多
Pediatric heart valve replacement(PHVR)remains a challenging procedure due to the uniqueanatomical and physiological characteristics of children,including growth and development,as well asthe long-term need for durabl...Pediatric heart valve replacement(PHVR)remains a challenging procedure due to the uniqueanatomical and physiological characteristics of children,including growth and development,as well asthe long-term need for durable valve function.This review provides an overview of both surgical andtranscatheter options for aortic,mitral,pulmonary,and tricuspid valve replacements in pediatric patients,highlighting the indications,outcomes,and advancements in technology and technique.Surgical valvereplacement traditionally involves the implantation of biological or mechanical prosthetic valves,withbiologicalvalves beingpreferred in children to reduce the need for lifelong anticoagulation therapy.However,the limitation ofbiological prostheses,nanely their inability to grow with the child,necessitates the frequentneed for reoperations.Recent innovations in valve engineering,such as the development of tissue engineeredand expandable valves,aim to address these issues.Transcatheter valve replacement(TVR)has emergedas a promising alternative,particularly for patients with complex anatomy or those who are high-risk fortraditional surgery.While the use of transcatheter devices in children remains limited due to the smallervascular size and limited long-termn data,several studies have demonstrated the feasibility and safety ofthe procedure in certain patient populations.Despite these advancements,challenges related to valvesize,durability,and the need for individualized treatment planning persist.The future of pediatric heartvalve replacemnent will likely involve a multidisciplinary approach combining surgical,transcatheter,andregenerative medicine strategies,aimed at optimizing outcomes,reducing the need for reinterventions,andimproving long-term quality of life for pediatric patients with valvularheart disease.This article discussesall options availab le for patients with valvular dysfunction,making it easy for parents/patients to go to as areference source of information.展开更多
Background Transcatheter Aortic Valve Implantation(TAVI)has changed the treatment paradigm of the aortic stenosis(AS).It has become the treatment of choice in patients with symptomatic AS and surgical high risk,and a ...Background Transcatheter Aortic Valve Implantation(TAVI)has changed the treatment paradigm of the aortic stenosis(AS).It has become the treatment of choice in patients with symptomatic AS and surgical high risk,and a valid alternative to surgical aortic valve replacement in patients with low and medium surgical risk.Despite numerous evidence on clinical results,indications and benefits,only a few studies analyse it from patient's perspective and the impact of TAVI on them.The objective of this study is to evaluate the experience of patients undergoing TAVI.Methods Cross-sectional,descriptive observational study in two Spanish hospitals,with a establish Nurse TAVI program,with100 patients undergoing TAVI.A specific questionnaire was designed(VALVEX questionnaire)and a pilot study was conducted by a multidisciplinary team of doctors,nurses and patients.The questionnaire was given to patients at 30 days after TAVI procedure during the follow up at the TAVI nurse clinic.Results The study demonstrated a mean satisfaction of 9 for the TAVI program,with 96%of patients that would recommend TAVI to other patients.Patients scored a high satisfaction on the information received prior to the procedure.During the procedure and admission,the satisfaction was high in relation to the care received.During the follow up,satisfaction was high in relation to the role of the TAVI nurse,for the information and continuation of care during the procedure,in reducing anxiety,organising their admission and understanding the process.However,questions with less scores were related to hospital catering,delay between diagnosed and treatment,and patient decision-making process.Conclusion The evaluation of patient experience allows us to improve the information given to the patient during their TAVI process and it can also allow patients to be more relax,aware and prepared for the procedure.Continuous follow up enables monitoring of patient recovery and helps to discuss any doubts improving patient's satisfaction.The use of PREMs and PROMs associated to TAVI pathway combined with an active participation of the patient on the design of the questionnaire is essential for keeping the patient in the centre of the TAVI pathway.展开更多
Aortic stenosis(AS)is the most common valvular heart disease,with a prevalence of over 4%among octogenarians.[1]The prevalence of autopsy-confirmed wild-type transthyretin cardiac amyloidosis(ATTRwt-CA)increases with ...Aortic stenosis(AS)is the most common valvular heart disease,with a prevalence of over 4%among octogenarians.[1]The prevalence of autopsy-confirmed wild-type transthyretin cardiac amyloidosis(ATTRwt-CA)increases with age,accounting for 25%of patients aged 85 years and older in Europe and 12%of patients older than 80 years in Japan.[2,3]Recent studies have reported that ATTRwt-CA coexists in 11%-16%of older patients with AS undergoing transcatheter aortic valve replacement(TAVR).[1,4,5]In a metaanalysis by Ho et al.,[6]the prevalence rates of cardiac amyloidosis,predominantly ATTRwt-CA,in patients with AS and those referred for TAVR or surgical aortic valve replacement(SAVR)were 14.4%and 15.2%,respectively.Conversely,the prevalence of AS in patients with cardiac amyloidosis is 8.7%.Owing to the high surgical risk in patients with both AS and ATTRwt-CA,TAVR may be preferred over SAVR.展开更多
Cardiac papillary fibroelastoma is a benign heart tumor that,despite its histologically benign nature,can have devastating clinical consequences.Advances in cardiac imaging have made papillary fibroelastoma the most c...Cardiac papillary fibroelastoma is a benign heart tumor that,despite its histologically benign nature,can have devastating clinical consequences.Advances in cardiac imaging have made papillary fibroelastoma the most common primary benign tumor,surpassing cardiac myxoma.These tumors predominantly occur on the surface of heart valves,with the aortic valve being the most frequently affected(44%),followed by the mitral valve(35%)and other locations.Aortic fibroelastomas are the second most common primary cardiac tumor,known for their risk of embolic complications.Surgical excision is recommended for symptomatic lesions,but the management of small and asymptomatic fibroelastomas remains uncertain,particularly in elderly patients with comorbidities.[1-3].展开更多
Residual atrioventricular valve regurgitation after correction of complete atrioventricular septal defect(cAVSD)is still not ideal.As a modification of the double-patch method,our technique comprises a suture-bite-wid...Residual atrioventricular valve regurgitation after correction of complete atrioventricular septal defect(cAVSD)is still not ideal.As a modification of the double-patch method,our technique comprises a suture-bite-wide strip of a third patch that is incorporated to the upper margin of the left side of the ventricular septal defect(VSD)patch.This third patch counteracts not only the valvular tissue loss caused by the suture bites but also the rightward displacement of the VSD patch in a bulged fashion that occurs with increased left ventricular pressure after weaning from cardiopulmonary bypass.This unfavorable outcome was addressed with the current technique through augmentation of the left-sided bridging leaflets serving to prevent the separation of them from their corresponding mural leaflets.The concept was applied in two cases with Down syndrome aged 5 months and 6 months,respectively,as a rescue procedure in the same session just after a failed cAVSD repair.Since the immediate-and short-term outcomes of the atrioventricular valves in regard to regurgitation are satisfying,we believe that the technique proposed herein holds promise for the future in terms of tackling residual atrioventricular valve regurgitation.展开更多
A bicuspid aortic valve,from autologous tissue,with growth potential can be constructed using the simple,and reproducible telescoping arterial trunk technique.
Hydraulic technology has the outstanding advantages of easy pressure compensation and high power density.It is an indispensable part of subsea equipment,such as deep-sea operations and submersible propulsion.There are...Hydraulic technology has the outstanding advantages of easy pressure compensation and high power density.It is an indispensable part of subsea equipment,such as deep-sea operations and submersible propulsion.There are few studies on electrohydraulic servo valves(EHSVs)in the deep sea.In this work,a novel electro-hydraulic servo rotary valve is designed,and its mathematical model is established.The analysis considers the variations in physical parameters such as temperature,ambient pressure,and oil viscosity resulting from changes in sea depth.This study focuses on the deformation of the rotary valve and the consequent alterations in leakage and friction torque.The findings indicate that at a depth of 12000 m,the fit clearance between the valve spool and the valve sleeve is 0.00413 mm,representing a 17%reduction compared with the clearance in a land environment.Then,the response of the rotary valve to depth is analyzed.The results indicate that the bandwidth of the rotary valve decreases with increasing depth.This study provides a reference for the use of the EHSV in the deep sea.展开更多
Bicuspid aortic valve (BAV) is a common congenital heart valve disease, often accompanied by aortic valve stenosis or regurgitation, infective endocarditis, and aortic diseases such as aortic dilation and dissection. ...Bicuspid aortic valve (BAV) is a common congenital heart valve disease, often accompanied by aortic valve stenosis or regurgitation, infective endocarditis, and aortic diseases such as aortic dilation and dissection. This article aims to review the definition, pathogenesis and genetic basis, classification methods, clinical features and current status of research and treatment and prognosis of BAV, and provide reference for the diagnosis and treatment of BAV. The content and structure of this article are as follows: The first part introduces the definition of BAV;The second part introduces the etiology and classification methods of BAV;The third part briefly describes the clinical manifestations and diagnosis of BAV;The fourth part discusses the treatment strategies and prognosis prediction of BAV;Finally, the article summarizes and looks forward to the future research directions.展开更多
Severe aortic stenosis has increased exponentially as a result of the aging of the population.Transcatheter aortic valve replacement(TAVR)procedures increase by 20%-30%per year in Spain.Referred patients are increasin...Severe aortic stenosis has increased exponentially as a result of the aging of the population.Transcatheter aortic valve replacement(TAVR)procedures increase by 20%-30%per year in Spain.Referred patients are increasingly older,have comorbidities,and frailty.TAVR cardiac rehabilitation(CR)programs significantly improve both functional capacity and quality of life of patients.However,there are no guidelines on how to carry out them and few elderly patients are referred to CR.Furthermore,mortality in women who undergo TAVR is higher than in men and even fewer are referred to CR programs.Multidisciplinary patient care,including comorbidities and frailty,is essential.It is necessary to ensure exquisite continuity of care during TAVR,CR,and the rest of the patient's life.Telerehabilitation could be an option in some lower-risk patients to include more patients in CR programs after TAVR,given the high demand.This article reviews the evidence on why CR should be performed in post-TAVR patients and proposes a practical and novel approach to the care process and the recommended aspects and components of the CR program.展开更多
BACKGROUND Aortic root dilation,linked to bicuspid aortic valve(BAV)or tricuspid aortic valve(TAV),risks aneurysm and dissection.Valve-sparing aortic root replacement(VSARR)preserves native valves,avoiding prosthetic ...BACKGROUND Aortic root dilation,linked to bicuspid aortic valve(BAV)or tricuspid aortic valve(TAV),risks aneurysm and dissection.Valve-sparing aortic root replacement(VSARR)preserves native valves,avoiding prosthetic valve complications.Longterm VSARR durability,especially in BAV patients,is debated.We hypothesize that VSARR outcomes differ between BAV and TAV patients in short-term and long-term settings.AIM To investigate short-term and long-term outcomes of VSARR in BAV vs TAV patients.METHODS This Preferred Reporting Items for Systematic Reviews and Meta-Analyses-compliant meta-analysis included observational studies comparing VSARR in adult BAV vs TAV patients.PubMed,ScienceDirect,and EMBASE were searched from inception to June 2025.Outcomes included mortality,reintervention,and procedural times.Pooled relative risk(RR)and mean differences(MD)with 95%CI were calculated.Risk of bias was assessed using Risk of Bias in Non-randomized Studies of Interventions;evidence certainty via GRADE.RESULTS Thirteen observational studies involving 1419 BAV and 2349 TAV patients were included.In-hospital mortality(RR=0.34,95%CI:0.10-1.14,P=0.08)and reoperation(RR=1.04,95%CI:0.64-1.69,P=0.87)showed no significant differences.All-cause mortality risk was significantly lower in BAV patients(RR=0.34,95%CI:0.13-0.86,P=0.02).Overall reintervention risk was significantly greater in BAV patients(RR=2.64,95%CI:1.96-3.55,P<0.00001).Aortic cross-clamp(MD=3.35 minutes,95%CI:-5.06 to 11.76,P=0.43)and cardiopulmonary bypass times(MD=3.96 minutes,95%CI:-10.26 to 18.18,P=0.59)showed no significant differences but substantial heterogeneity.The certainty of evidence was moderate for reintervention,low for mortality risk and in-hospital reoperation,and very low for procedural times.CONCLUSION VSARR demonstrates comparable short-term safety between BAV and TAV patients.However,BAV patients face a significantly higher long-term reintervention risk,highlighting the need for tailored strategies and further research.展开更多
Magnetization convenience is crucial consideration for design of valve magnetic actuators.The existing repulsive-magnetic-coupling of 2D maglev valve is not oriented to the integral-magnetization-processes,resulting i...Magnetization convenience is crucial consideration for design of valve magnetic actuators.The existing repulsive-magnetic-coupling of 2D maglev valve is not oriented to the integral-magnetization-processes,resulting in the high assembly cost.This paper presents a novel tractive-magnetic-coupling(TMC)and its application on a 2D electro-hydraulic proportional flow valve(2D-EHPFV),whose configuration not only fulfill the requirements of 2D valve,but also oriented to integral-magnetization-process.To investigate the output torque of TMC,a detailed analytical model considering leakage flux,edge effect and tooth magnetic saturation is formulated based on the equivalent magnetic circuit method.To facilitate the magnetic saturation calculation,a special magnetic permeability database is established for tooth region of TMC using Ansoft/Maxwell software.Prototype of TMC is machined and an exclusive experimental platform is built.Torque-displacement characteristics under different working airgap and tooth number are measured.The experimental results are in good agreement with the analytical results,which verifies the correctness of the analytical model.Then the TMC is integrated into the 2D-EHPFV by replacing the repulsive-magnetic-coupling.Prototype of 2D-EHPFV is designed and manufactured to test the no-load flow characteristics,load flow characteristics,leakage characteristics,frequency characteristics and step response.Under working pressure of 15 MPa,the maximum no-load flow rate is 82.2 L/min with the hysteresis of 2.6%,and the amplitude and phase frequency width is 21.6 Hz,and 28.9 Hz.The detailed experimental results show that TMC can be applied to 2D valves to form 2D-EHPFV,which can reduce hysteresis and cost,and improve response speed.展开更多
BACKGROUND The Perceval Sorin S(perceval valve)is a sutureless bioprosthetic designed for use in a high-risk cohort who may not be suitable for transcatheter aortic valve implantation or a conventional surgical aortic...BACKGROUND The Perceval Sorin S(perceval valve)is a sutureless bioprosthetic designed for use in a high-risk cohort who may not be suitable for transcatheter aortic valve implantation or a conventional surgical aortic valve replacement(AVR).AIM To compare five-year post-operative outcomes in a cohort undergoing isolated AVR with the perceval valve to a contemporary cohort undergoing surgical AVR with a sutured bioprosthesis.METHODS This study was a retrospective,cohort study at a single tertiary unit.Between 2017 and 2023,982 suitable patients were identified.174 Perceval valve replacements were matched to 174 sutured valve replacements.Cohort characteristics,intra-operative details,and post-operative outcomes were compared between the two groups.RESULTS Time under the aortic cross-clamp(P<0.001),time on the cardiopulmonary bypass(P<0.001)and total operative time(P<0.001)were significantly reduced in the Perceval group.Patients in the Perceval valve group were at a lower risk of postoperative pneumonia[odds ratio(OR)=0.53(0.29-0.94)]and atrial fibrillation[OR=0.58(0.36-0.93)].After propensity-matching,all-cause mortality did not significantly differ between the two groups in the five-year follow-up period.Larger valve sizes conferred an increased risk of mortality(P=0.020).CONCLUSION Sutureless surgical AVR(SAVR)is a safe and efficient alternative to SAVR with a sutured bioprosthesis,and may confer a reduced risk of post-operative atrial fibrillation.Clinician tendency towards‘oversizing’sutureless aortic valves translates into adverse clinical outcomes.Less time on the cardiopulmonary bypass circuit allows for the treatment of otherwise high-risk patients.展开更多
Particularly commendable is the important work of Calvo,et al.[1]in comparing geriatric assessment tools to predict mortality and readmissions in elderly patients undergoing transcatheter aortic valve implantation(TAV...Particularly commendable is the important work of Calvo,et al.[1]in comparing geriatric assessment tools to predict mortality and readmissions in elderly patients undergoing transcatheter aortic valve implantation(TAVI).Their efforts underscore the growing importance of frailty assessment in cardiovascular risk stratification.We would like to respectfully highlight several areas that,if addressed in future studies(Figure 1),could further enhance the utility and inclusivity of these assessments.展开更多
BACKGROUND Valvular heart disease affects more than 100 million people worldwide and is associated with significant morbidity and mortality.The prevalence of at least moderate valvular heart disease is 2.5%across all ...BACKGROUND Valvular heart disease affects more than 100 million people worldwide and is associated with significant morbidity and mortality.The prevalence of at least moderate valvular heart disease is 2.5%across all age groups,but its prevalence increases with age.Mitral regurgitation and aortic stenosis are the most frequent types of valvular heart disease in the community and hospital context,res-pectively.Surgical valve replacement(or mitral valve repair)is the standard of care for treating heart valve disease.However,the replacement of a prosthetic heart valve can lead to complications,either in the peri-procedural phase or in the long-term follow-up period.CASE SUMMARY We present a case of a 71-year-old female patient with a history of mitral valve replacement and warfarin anti-coagulation therapy.She was admitted to the intensive care unit due to spontaneously reperfused ischemic stroke of probable cardioembolic etiology.A dysfunctional mitral prosthesis was identified due to malfunction of one of the fixed discs.Furthermore,a possible microthrombotic lesion was suspected.Therefore,systemic thrombolysis was performed with subsequent normalization of mitral disc opening and closing.CONCLUSION This case underscores the critical importance of a multidisciplinary approach for timely decision-making in critically ill patients with prosthetic valve complications.展开更多
The incidence of new-onset cardiac conduction disturbances following transcatheter aortic valve implantation(TAVI)has not decreased compared to other complications,and nowadays is by far the most frequent drawback fol...The incidence of new-onset cardiac conduction disturbances following transcatheter aortic valve implantation(TAVI)has not decreased compared to other complications,and nowadays is by far the most frequent drawback following the procedure.Meanwhile,the global management of TAVI recipients has led to a minimalist approach with short postprocedural length of stay,which may be limited by the occurrence of late arrhythmic events in patients at high-risk.This review focuses on those strategies to overcome the conundrum between early discharge and new-onset conduction disturbances in elderly TAVI candidates and provides a perspective on future improvements in this field.展开更多
Background Hypertension is associated with an increased risk of calcific aortic valve stenosis(CAVS).However,the directionality of causation between blood pressure traits and aortic stenosis is unclear,as is the benef...Background Hypertension is associated with an increased risk of calcific aortic valve stenosis(CAVS).However,the directionality of causation between blood pressure traits and aortic stenosis is unclear,as is the benefit of antihypertensive drugs for CAVS.Methods Using genome-wide association studies(GWAS)summary statistics,we performed bidirectional two-sample univariable mendelian randomization(UVMR)to assess the causal associations of systolic blood pressure(SBP),diastolic blood pressure(DBP),and pulse pressure(PP)with CAVS.Multivariable mendelian randomization(MVMR)was conducted to evaluate the direct effect of hypertension on CAVS,adjusting for confounders.Drug target mendelian randomization(MR)and summary-level MR(SMR)were used to estimate the effects of 12 classes of antihypertensive drugs and their target genes on CAVS risk.Inverse variance weighting was the primary MR method,with sensitivity analyses to validate results.Results UVMR showed SBP,DBP,and PP have causal effects on CAVS,with no significant reverse causality.MVMR confirmed the causality between hypertension and CAVS after adjusting for confounders.Drug-target MR analyses indicated that calcium channel blockers(CCBs),loop diuretics,and thiazide diuretics via SBP lowering exerted protective effects on CAVS risk.SMR analysis showed that the CCBs target gene CACNA2D2 and ARBs target gene AGTR1 were positively associated with CAVS risk,while diuretics target genes SLC12A5 and SLC12A1 were negatively associated with aortic stenosis risk.Conclusions Hypertension has a causal relationship with CAVS.Managing SBP in hypertensive patients with CCBs may prevent CAVS.ARBs might exert protective effects on CAVS independent of blood pressure reduction.The relationship between diuretics and CAVS is complex,with opposite effects through different mechanisms.展开更多
文摘A set of novel nonlinear variable structure excitation and steam-valving controllers are proposed in this paper. On the basis of the classical dynamic equations of a generator, excitation control and steam valving control are simultaneously considered. Design of these controllers combines the differential geometry theory with the variable structure controlling theory. The mathematical model in the form of ＂an affine nonlinear system＂ is set up for the control design of a large-scale power plant. The dynamic performance of the nonlinear variable structure controllers proposed for a single machine connected to an infinite bus power system is simulated. Simulation results show that the nonlinear variable structure excitation and steam-valving controllers give satisfactory dynamic performance and good robustness.
基金supported by the National Natural Science Foundation of China(No.52175067)the Zhejiang Key Research&Development Project(No.2021C01021)+1 种基金the Natural Science Foundation of Zhejiang Province(No.LY20E050016)the Postdoctoral Fellowship Program of China Postdoctoral Science Foundation(CPSF)(No.GZC20241478)。
文摘A high-temperature and high-pressure valve is the key equipment of a wind tunnel system;it controls the generation of high-temperature and high-pressure gas.To reduce the adverse impact of high-temperature and high-pressure gas on the strength of the valve body,a cooling structure is set on the valve seat.This can significantly reduce the temperature of the valve body and valve seat.The effects of its structure on the cooling characteristics and stress of the valve seat are studied,and six main parameters that can completely describe the geometry of the cooling structure are proposed.The central composite design method is used to select sample points,and the multi-objective genetic algorithm(MOGA)method is used for optimal structural design.A modification method according to the main parameters for the valve seat is proposed.The results show that the cooling structure weakens the pressure-bearing capability of the valve seat.Among the six main parameters of the valve seat,the distance from the end face of the lower hole to the Z-axis and the distance from the axis of the lower hole to the origin of the coordinates have the most obvious effects on the average stress of the valve seat.An optimum design value is proposed.This work can provide a reference for the design of high-temperature and high-pressure valves.
文摘BACKGROUND The management of severe symptomatic aortic stenosis has been revolutionized by transcatheter aortic valve replacement(TAVR),offering a minimally invasive alternative to surgical aortic valve replacement(SAVR).However,the compara-tive safety and efficacy of these interventions remain subjects of ongoing investigation.AIM To compare the clinical outcomes and safety of TAVR vs SAVR in patients with severe symptomatic aortic stenosis.METHODS A systematic review and meta-analysis were conducted according to PRISMA guidelines.Randomized controlled trials(RCTs)comparing TAVR and SAVR were identified from databases including PubMed,Scopus,and Web of Science up to May 31,2024.Data were extracted on clinical outcomes,including mortality,procedural compli-cations,and post-procedure adverse events.Risk ratios(RRs)with 95%CIs were calculated using a random-effects model.RESULTS A total of 10 RCTs were included.TAVR demonstrated a significantly lower risk of acute kidney injury(RR:0.33;95%CI:0.25–0.44),major bleeding(RR:0.37;95%CI:0.30–0.46),and new-onset atrial fibrillation(RR:0.44;95%CI:0.34–0.57)compared to SAVR.However,TAVR was associated with higher risks of new permanent pacemaker implantation(RR:3.49;95%CI:2.77–4.39),major vascular complications(RR:2.47;95%CI:1.91–3.21),and paraval-vular leaks(RR:4.15;95%CI:3.14–5.48).Mortality at 30 days was comparable(RR:0.95;95%CI:0.78–1.15),but long-term mortality was slightly higher with TAVR in some analyses(RR:1.23;95%CI:1.01–1.49).Rates of stroke(RR:0.97;95%CI:0.81–1.17)and myocardial infarction(RR:0.91;95%CI:0.67–1.24)were similar between the groups.CONCLUSION TAVR offers a less invasive option with significant benefits in reducing acute kidney injury,major bleeding,and new-onset atrial fibrillation,making it particularly advantageous for high-risk surgical candidates.However,higher risks of permanent pacemaker implantation,vascular complications,and paravalvular leaks highlight the need for individualized patient selection and shared decision-making to optimize outcomes.
文摘Background There is scarce data about comparisons between geriatric assessment tools in patients with aortic stenosis(AS).We aimed to describe the geriatric profile of patients with AS undergoing transcatheter aortic valve implantation(TAVI)and to analyze the ability of different tools for predicting clinical outcomes in this context.Methods This was a single center retrospective registry including patients with AS undergoing TAVI and surviving to hospital discharge.The primary endpoint was all-cause mortality or need for urgent readmission one year after TAVI.Results A total of 377 patients were included(mean age of 80.4 years).Most patients were independent or mildly dependent,with an optimal cognitive status.The proportion of frailty ranged from 17.6%to 49.8%.A total of 20 patients(5.3%)died and 110/377 patients(29.2%)died or were readmitted during follow up.Overall,most components of the geriatric assessment showed an association with clinical outcomes.Disability for instrumental activities showed a significant association with mortality and a strong association with the rate of mortality or readmission.The association between frailty and clinical outcomes was higher for short physical performance battery(SPPB),essential frailty toolset(EFT)and the frailty index based on comprehensive geriatric assessment(IF-VIG)and lower for Fried criteria and FRAIL scale.Conclusions AS patients from this series presented a good physical performance,optimal cognitive status and a reasonably low prevalence of frailty.The best predictive ability was observed for disability for instrumental activities and frailty as measured by the EFT,SPPB and the IF-VIG.
文摘Pediatric heart valve replacement(PHVR)remains a challenging procedure due to the uniqueanatomical and physiological characteristics of children,including growth and development,as well asthe long-term need for durable valve function.This review provides an overview of both surgical andtranscatheter options for aortic,mitral,pulmonary,and tricuspid valve replacements in pediatric patients,highlighting the indications,outcomes,and advancements in technology and technique.Surgical valvereplacement traditionally involves the implantation of biological or mechanical prosthetic valves,withbiologicalvalves beingpreferred in children to reduce the need for lifelong anticoagulation therapy.However,the limitation ofbiological prostheses,nanely their inability to grow with the child,necessitates the frequentneed for reoperations.Recent innovations in valve engineering,such as the development of tissue engineeredand expandable valves,aim to address these issues.Transcatheter valve replacement(TVR)has emergedas a promising alternative,particularly for patients with complex anatomy or those who are high-risk fortraditional surgery.While the use of transcatheter devices in children remains limited due to the smallervascular size and limited long-termn data,several studies have demonstrated the feasibility and safety ofthe procedure in certain patient populations.Despite these advancements,challenges related to valvesize,durability,and the need for individualized treatment planning persist.The future of pediatric heartvalve replacemnent will likely involve a multidisciplinary approach combining surgical,transcatheter,andregenerative medicine strategies,aimed at optimizing outcomes,reducing the need for reinterventions,andimproving long-term quality of life for pediatric patients with valvularheart disease.This article discussesall options availab le for patients with valvular dysfunction,making it easy for parents/patients to go to as areference source of information.
基金funded by a IBYE23_0002 grant supported by Instituto de investigación biom-édica de Salamanca IBSAL,Castilla y León (Spain) and by a GRS 2860/A1/2023 by Gerencia Regional de Salud o f Castilla y León (Spain)。
文摘Background Transcatheter Aortic Valve Implantation(TAVI)has changed the treatment paradigm of the aortic stenosis(AS).It has become the treatment of choice in patients with symptomatic AS and surgical high risk,and a valid alternative to surgical aortic valve replacement in patients with low and medium surgical risk.Despite numerous evidence on clinical results,indications and benefits,only a few studies analyse it from patient's perspective and the impact of TAVI on them.The objective of this study is to evaluate the experience of patients undergoing TAVI.Methods Cross-sectional,descriptive observational study in two Spanish hospitals,with a establish Nurse TAVI program,with100 patients undergoing TAVI.A specific questionnaire was designed(VALVEX questionnaire)and a pilot study was conducted by a multidisciplinary team of doctors,nurses and patients.The questionnaire was given to patients at 30 days after TAVI procedure during the follow up at the TAVI nurse clinic.Results The study demonstrated a mean satisfaction of 9 for the TAVI program,with 96%of patients that would recommend TAVI to other patients.Patients scored a high satisfaction on the information received prior to the procedure.During the procedure and admission,the satisfaction was high in relation to the care received.During the follow up,satisfaction was high in relation to the role of the TAVI nurse,for the information and continuation of care during the procedure,in reducing anxiety,organising their admission and understanding the process.However,questions with less scores were related to hospital catering,delay between diagnosed and treatment,and patient decision-making process.Conclusion The evaluation of patient experience allows us to improve the information given to the patient during their TAVI process and it can also allow patients to be more relax,aware and prepared for the procedure.Continuous follow up enables monitoring of patient recovery and helps to discuss any doubts improving patient's satisfaction.The use of PREMs and PROMs associated to TAVI pathway combined with an active participation of the patient on the design of the questionnaire is essential for keeping the patient in the centre of the TAVI pathway.
文摘Aortic stenosis(AS)is the most common valvular heart disease,with a prevalence of over 4%among octogenarians.[1]The prevalence of autopsy-confirmed wild-type transthyretin cardiac amyloidosis(ATTRwt-CA)increases with age,accounting for 25%of patients aged 85 years and older in Europe and 12%of patients older than 80 years in Japan.[2,3]Recent studies have reported that ATTRwt-CA coexists in 11%-16%of older patients with AS undergoing transcatheter aortic valve replacement(TAVR).[1,4,5]In a metaanalysis by Ho et al.,[6]the prevalence rates of cardiac amyloidosis,predominantly ATTRwt-CA,in patients with AS and those referred for TAVR or surgical aortic valve replacement(SAVR)were 14.4%and 15.2%,respectively.Conversely,the prevalence of AS in patients with cardiac amyloidosis is 8.7%.Owing to the high surgical risk in patients with both AS and ATTRwt-CA,TAVR may be preferred over SAVR.
文摘Cardiac papillary fibroelastoma is a benign heart tumor that,despite its histologically benign nature,can have devastating clinical consequences.Advances in cardiac imaging have made papillary fibroelastoma the most common primary benign tumor,surpassing cardiac myxoma.These tumors predominantly occur on the surface of heart valves,with the aortic valve being the most frequently affected(44%),followed by the mitral valve(35%)and other locations.Aortic fibroelastomas are the second most common primary cardiac tumor,known for their risk of embolic complications.Surgical excision is recommended for symptomatic lesions,but the management of small and asymptomatic fibroelastomas remains uncertain,particularly in elderly patients with comorbidities.[1-3].
文摘Residual atrioventricular valve regurgitation after correction of complete atrioventricular septal defect(cAVSD)is still not ideal.As a modification of the double-patch method,our technique comprises a suture-bite-wide strip of a third patch that is incorporated to the upper margin of the left side of the ventricular septal defect(VSD)patch.This third patch counteracts not only the valvular tissue loss caused by the suture bites but also the rightward displacement of the VSD patch in a bulged fashion that occurs with increased left ventricular pressure after weaning from cardiopulmonary bypass.This unfavorable outcome was addressed with the current technique through augmentation of the left-sided bridging leaflets serving to prevent the separation of them from their corresponding mural leaflets.The concept was applied in two cases with Down syndrome aged 5 months and 6 months,respectively,as a rescue procedure in the same session just after a failed cAVSD repair.Since the immediate-and short-term outcomes of the atrioventricular valves in regard to regurgitation are satisfying,we believe that the technique proposed herein holds promise for the future in terms of tackling residual atrioventricular valve regurgitation.
基金funded by internal grants from the Ward Family Heart Center.
文摘A bicuspid aortic valve,from autologous tissue,with growth potential can be constructed using the simple,and reproducible telescoping arterial trunk technique.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFC2805703)the Major Training Program of University Research and Innovation Platform of Gansu Provincial Department of Education(Grant No.2024CXPT-09).
文摘Hydraulic technology has the outstanding advantages of easy pressure compensation and high power density.It is an indispensable part of subsea equipment,such as deep-sea operations and submersible propulsion.There are few studies on electrohydraulic servo valves(EHSVs)in the deep sea.In this work,a novel electro-hydraulic servo rotary valve is designed,and its mathematical model is established.The analysis considers the variations in physical parameters such as temperature,ambient pressure,and oil viscosity resulting from changes in sea depth.This study focuses on the deformation of the rotary valve and the consequent alterations in leakage and friction torque.The findings indicate that at a depth of 12000 m,the fit clearance between the valve spool and the valve sleeve is 0.00413 mm,representing a 17%reduction compared with the clearance in a land environment.Then,the response of the rotary valve to depth is analyzed.The results indicate that the bandwidth of the rotary valve decreases with increasing depth.This study provides a reference for the use of the EHSV in the deep sea.
文摘Bicuspid aortic valve (BAV) is a common congenital heart valve disease, often accompanied by aortic valve stenosis or regurgitation, infective endocarditis, and aortic diseases such as aortic dilation and dissection. This article aims to review the definition, pathogenesis and genetic basis, classification methods, clinical features and current status of research and treatment and prognosis of BAV, and provide reference for the diagnosis and treatment of BAV. The content and structure of this article are as follows: The first part introduces the definition of BAV;The second part introduces the etiology and classification methods of BAV;The third part briefly describes the clinical manifestations and diagnosis of BAV;The fourth part discusses the treatment strategies and prognosis prediction of BAV;Finally, the article summarizes and looks forward to the future research directions.
文摘Severe aortic stenosis has increased exponentially as a result of the aging of the population.Transcatheter aortic valve replacement(TAVR)procedures increase by 20%-30%per year in Spain.Referred patients are increasingly older,have comorbidities,and frailty.TAVR cardiac rehabilitation(CR)programs significantly improve both functional capacity and quality of life of patients.However,there are no guidelines on how to carry out them and few elderly patients are referred to CR.Furthermore,mortality in women who undergo TAVR is higher than in men and even fewer are referred to CR programs.Multidisciplinary patient care,including comorbidities and frailty,is essential.It is necessary to ensure exquisite continuity of care during TAVR,CR,and the rest of the patient's life.Telerehabilitation could be an option in some lower-risk patients to include more patients in CR programs after TAVR,given the high demand.This article reviews the evidence on why CR should be performed in post-TAVR patients and proposes a practical and novel approach to the care process and the recommended aspects and components of the CR program.
文摘BACKGROUND Aortic root dilation,linked to bicuspid aortic valve(BAV)or tricuspid aortic valve(TAV),risks aneurysm and dissection.Valve-sparing aortic root replacement(VSARR)preserves native valves,avoiding prosthetic valve complications.Longterm VSARR durability,especially in BAV patients,is debated.We hypothesize that VSARR outcomes differ between BAV and TAV patients in short-term and long-term settings.AIM To investigate short-term and long-term outcomes of VSARR in BAV vs TAV patients.METHODS This Preferred Reporting Items for Systematic Reviews and Meta-Analyses-compliant meta-analysis included observational studies comparing VSARR in adult BAV vs TAV patients.PubMed,ScienceDirect,and EMBASE were searched from inception to June 2025.Outcomes included mortality,reintervention,and procedural times.Pooled relative risk(RR)and mean differences(MD)with 95%CI were calculated.Risk of bias was assessed using Risk of Bias in Non-randomized Studies of Interventions;evidence certainty via GRADE.RESULTS Thirteen observational studies involving 1419 BAV and 2349 TAV patients were included.In-hospital mortality(RR=0.34,95%CI:0.10-1.14,P=0.08)and reoperation(RR=1.04,95%CI:0.64-1.69,P=0.87)showed no significant differences.All-cause mortality risk was significantly lower in BAV patients(RR=0.34,95%CI:0.13-0.86,P=0.02).Overall reintervention risk was significantly greater in BAV patients(RR=2.64,95%CI:1.96-3.55,P<0.00001).Aortic cross-clamp(MD=3.35 minutes,95%CI:-5.06 to 11.76,P=0.43)and cardiopulmonary bypass times(MD=3.96 minutes,95%CI:-10.26 to 18.18,P=0.59)showed no significant differences but substantial heterogeneity.The certainty of evidence was moderate for reintervention,low for mortality risk and in-hospital reoperation,and very low for procedural times.CONCLUSION VSARR demonstrates comparable short-term safety between BAV and TAV patients.However,BAV patients face a significantly higher long-term reintervention risk,highlighting the need for tailored strategies and further research.
基金Supported by National Natural Science Foundation of China(Grant Nos.51975524,52375067)Zhejiang Provincial Natural Science Foundation of China(Grant No.Y23E050014).
文摘Magnetization convenience is crucial consideration for design of valve magnetic actuators.The existing repulsive-magnetic-coupling of 2D maglev valve is not oriented to the integral-magnetization-processes,resulting in the high assembly cost.This paper presents a novel tractive-magnetic-coupling(TMC)and its application on a 2D electro-hydraulic proportional flow valve(2D-EHPFV),whose configuration not only fulfill the requirements of 2D valve,but also oriented to integral-magnetization-process.To investigate the output torque of TMC,a detailed analytical model considering leakage flux,edge effect and tooth magnetic saturation is formulated based on the equivalent magnetic circuit method.To facilitate the magnetic saturation calculation,a special magnetic permeability database is established for tooth region of TMC using Ansoft/Maxwell software.Prototype of TMC is machined and an exclusive experimental platform is built.Torque-displacement characteristics under different working airgap and tooth number are measured.The experimental results are in good agreement with the analytical results,which verifies the correctness of the analytical model.Then the TMC is integrated into the 2D-EHPFV by replacing the repulsive-magnetic-coupling.Prototype of 2D-EHPFV is designed and manufactured to test the no-load flow characteristics,load flow characteristics,leakage characteristics,frequency characteristics and step response.Under working pressure of 15 MPa,the maximum no-load flow rate is 82.2 L/min with the hysteresis of 2.6%,and the amplitude and phase frequency width is 21.6 Hz,and 28.9 Hz.The detailed experimental results show that TMC can be applied to 2D valves to form 2D-EHPFV,which can reduce hysteresis and cost,and improve response speed.
文摘BACKGROUND The Perceval Sorin S(perceval valve)is a sutureless bioprosthetic designed for use in a high-risk cohort who may not be suitable for transcatheter aortic valve implantation or a conventional surgical aortic valve replacement(AVR).AIM To compare five-year post-operative outcomes in a cohort undergoing isolated AVR with the perceval valve to a contemporary cohort undergoing surgical AVR with a sutured bioprosthesis.METHODS This study was a retrospective,cohort study at a single tertiary unit.Between 2017 and 2023,982 suitable patients were identified.174 Perceval valve replacements were matched to 174 sutured valve replacements.Cohort characteristics,intra-operative details,and post-operative outcomes were compared between the two groups.RESULTS Time under the aortic cross-clamp(P<0.001),time on the cardiopulmonary bypass(P<0.001)and total operative time(P<0.001)were significantly reduced in the Perceval group.Patients in the Perceval valve group were at a lower risk of postoperative pneumonia[odds ratio(OR)=0.53(0.29-0.94)]and atrial fibrillation[OR=0.58(0.36-0.93)].After propensity-matching,all-cause mortality did not significantly differ between the two groups in the five-year follow-up period.Larger valve sizes conferred an increased risk of mortality(P=0.020).CONCLUSION Sutureless surgical AVR(SAVR)is a safe and efficient alternative to SAVR with a sutured bioprosthesis,and may confer a reduced risk of post-operative atrial fibrillation.Clinician tendency towards‘oversizing’sutureless aortic valves translates into adverse clinical outcomes.Less time on the cardiopulmonary bypass circuit allows for the treatment of otherwise high-risk patients.
文摘Particularly commendable is the important work of Calvo,et al.[1]in comparing geriatric assessment tools to predict mortality and readmissions in elderly patients undergoing transcatheter aortic valve implantation(TAVI).Their efforts underscore the growing importance of frailty assessment in cardiovascular risk stratification.We would like to respectfully highlight several areas that,if addressed in future studies(Figure 1),could further enhance the utility and inclusivity of these assessments.
文摘BACKGROUND Valvular heart disease affects more than 100 million people worldwide and is associated with significant morbidity and mortality.The prevalence of at least moderate valvular heart disease is 2.5%across all age groups,but its prevalence increases with age.Mitral regurgitation and aortic stenosis are the most frequent types of valvular heart disease in the community and hospital context,res-pectively.Surgical valve replacement(or mitral valve repair)is the standard of care for treating heart valve disease.However,the replacement of a prosthetic heart valve can lead to complications,either in the peri-procedural phase or in the long-term follow-up period.CASE SUMMARY We present a case of a 71-year-old female patient with a history of mitral valve replacement and warfarin anti-coagulation therapy.She was admitted to the intensive care unit due to spontaneously reperfused ischemic stroke of probable cardioembolic etiology.A dysfunctional mitral prosthesis was identified due to malfunction of one of the fixed discs.Furthermore,a possible microthrombotic lesion was suspected.Therefore,systemic thrombolysis was performed with subsequent normalization of mitral disc opening and closing.CONCLUSION This case underscores the critical importance of a multidisciplinary approach for timely decision-making in critically ill patients with prosthetic valve complications.
文摘The incidence of new-onset cardiac conduction disturbances following transcatheter aortic valve implantation(TAVI)has not decreased compared to other complications,and nowadays is by far the most frequent drawback following the procedure.Meanwhile,the global management of TAVI recipients has led to a minimalist approach with short postprocedural length of stay,which may be limited by the occurrence of late arrhythmic events in patients at high-risk.This review focuses on those strategies to overcome the conundrum between early discharge and new-onset conduction disturbances in elderly TAVI candidates and provides a perspective on future improvements in this field.
基金supported by the National Natural Science Foundation of China(82170375,U23A20395)1.3.5 project for disciplines of excellence from West China Hospital of Sichuan University(ZYGD23021,23HXF-H009)Sichuan Science and Technology Program 2023NSFSC1645。
文摘Background Hypertension is associated with an increased risk of calcific aortic valve stenosis(CAVS).However,the directionality of causation between blood pressure traits and aortic stenosis is unclear,as is the benefit of antihypertensive drugs for CAVS.Methods Using genome-wide association studies(GWAS)summary statistics,we performed bidirectional two-sample univariable mendelian randomization(UVMR)to assess the causal associations of systolic blood pressure(SBP),diastolic blood pressure(DBP),and pulse pressure(PP)with CAVS.Multivariable mendelian randomization(MVMR)was conducted to evaluate the direct effect of hypertension on CAVS,adjusting for confounders.Drug target mendelian randomization(MR)and summary-level MR(SMR)were used to estimate the effects of 12 classes of antihypertensive drugs and their target genes on CAVS risk.Inverse variance weighting was the primary MR method,with sensitivity analyses to validate results.Results UVMR showed SBP,DBP,and PP have causal effects on CAVS,with no significant reverse causality.MVMR confirmed the causality between hypertension and CAVS after adjusting for confounders.Drug-target MR analyses indicated that calcium channel blockers(CCBs),loop diuretics,and thiazide diuretics via SBP lowering exerted protective effects on CAVS risk.SMR analysis showed that the CCBs target gene CACNA2D2 and ARBs target gene AGTR1 were positively associated with CAVS risk,while diuretics target genes SLC12A5 and SLC12A1 were negatively associated with aortic stenosis risk.Conclusions Hypertension has a causal relationship with CAVS.Managing SBP in hypertensive patients with CCBs may prevent CAVS.ARBs might exert protective effects on CAVS independent of blood pressure reduction.The relationship between diuretics and CAVS is complex,with opposite effects through different mechanisms.
