Patient-specific bicuspid aortic valve hemodynamics study based on computer simulation and in vitro experiment

Bicuspid aortic valve(BAV)is a common congenital malformation of the aortic valve with various structural characteristics.Different types of BAV can cause secondary aortic diseases,including calcific aortic valve stenosis and aortic dilation,although their pathogenesis remains unclear.In this study,we first established patient-specific BAV simulation models and silicone models(Type 0 A-P,Type 1 R-N,and Type 1 L-R)based on clinical computed tomography angiography(CTA)and pressure data.Next,we applied a research method combining fluid-structure interaction(FSI)simulation and digital particle image velocimetry(DPIV)experiment to quantitatively analyze the hemodynamic,structural mechanical,and flow field characteristics of patients with different BAV types.Simulation-based hemodynamic parameters and experimental results were consistent with clinical data,affirming the accuracy of the model.The location of the maximum principal strain in the patientspecific model was associated with the calcification site,which characterized the mechanism of secondary aortic valve stenosis.The maximum wall shear stress(WSS)of the patient-specific model(>67.1 Pa)exceeded 37.9 Pa and could cause endothelial surface injury as well as remodeling under long-term exposure,thus increasing the risk of aortic dilation.The distribution of WSS was mainly caused by BAV type,resulting in different degrees of dilation in different parts guided by the type.The patient-specific model revealed a maximum viscous shear stress(VSS)value of 5.23 Pa,which was smaller than the threshold for shear-induced hemolysis of red blood cells(150 Pa)and platelet activation(10 Pa),but close to the threshold for platelet sensitization(6 Pa).The results of flow field characteristics revealed a low risk of hemolysis but a relative high risk of thrombus formation in the patient-specific model.This study not only provides a basis for future comprehensive research on BAV diseases,but also generates relevant insights for theoretical guidance for calcific aortic valve stenosis and aortic dilation caused by different types of BAV,as well as biomechanical evidence for the potential risk of hemolysis and thrombus formation in BAV,which is of great value for clinical diagnosis and treatment of BAV.

Bicuspid aortic valve with associated aortopathy, significant left ventricular hypertrophy or concomitant hypertrophic cardiomyopathy: A diagnostic and therapeutic challenge

Due to its prevalence of 0.5%to 2%in the general population,with a 75%predominance among men,bicuspid aortic valve is the most common congenital heart defect.It is frequently accompanied by other cardiac congenital anomalies,and clinical presentation can vary significantly,with stenosis being the most common manifestation,often resulting in mild to moderate concentric hypertrophy of the left ventricle.Echocardiography is the primary diagnostic modality utilized for establishing the diagnosis,and it is often the sole diagnostic tool relied upon by clinicians.However,due to the heterogeneous clinical presentation and possible associated anomalies(which are often overlooked in clinical practice),it is necessary to employ various diagnostic methods and persist in finding the accurate diagnosis if multiple inconsistencies exist.By employing this approach,we can effectively manage these patients and provide them with appropriate treatment.Through a clinical case from our practice,we provide an overview of the literature on bicuspid aortic valve with aortophaty and the possible association with hypertrophic cardiomyopathy,diagnostic methods,and treatment options.This review article highlights the critical significance of achieving an accurate diagnosis in patients with bicuspid aortic valve and significant left ventricular hypertrophy.It is crucial to exclude other possible causes of left ventricular outflow tract obstruction,such as sub-or supra-aortic obstructions,and hypertrophic cardiomyopathy.

Extent of Degenerative Changes in Ascending Aorta of Patients with Bicuspid Aortic Valve (BAV)—A Histopathological Study

Objective: To find out, whether the degenerative process of ascending aorta is limited to the aortic sinuses only or is extending to mid and distal ascending aorta of Bicuspid Aortic Valve patients. Method: A prospective consecutive study on 25 patients of BAV (undergoing aortic valve with ± ascending aortic surgeries) was conducted from 1st Jan 2010 to 30th Dec 2011. Morphological and anatomical data of root and ascending aorta were recorded from echocardiography and computed tomography angiography. Intra-operatively, aortic tissue biopsy taken from three sites: sinus, mid, and distal ascending aorta. Histological evaluation of the aortic wall was based on criteria adapted from Schlatmann and Becker and from de Sa et al. The presence and degree of the 5 variables of degeneration were studied: Linear regression and correlation were used to get relationship between histopathological scoring (HPE-T) and aortic diameter for each site of ascending aorta. Results: Significant linear relation was found between aortic sinus diameter and HPE T score with R value = 0.590 (p value 0.001) and variance of 37.5%. Analysis suggests that HPE T Score = -5.139 + (0.188 x Ao. Sinus Diameter in mm). No significant linear relation could be established between mid and distal ascending aorta diameter and HPE T scoring. Conclusion: In BAV patient’s, a definite relationship between degenerative changes of aortic media and aortic diameter was found and was limited up to the sinus level only. Thus, the study reinforces the thought of replacing aortic sinus too while dealing with aortic valve, even without significant dilatation. By this aggressive management of aortic root, progression of aortic dilatation or dissection can be prevented in bicuspid aortic valve patients.

Bicuspidization Using the Open-Sleeve Technique for Congenital Aortic Stenosis during Infancy

Congenital aortic stenosis(cAS)frequently requires intervention during the neonatal or infantile period.However,surgical repair is challenging because of the narrow surgical space.We performed bicuspidization using the open-sleeve technique for cAS with a unicuspid aortic valve in two patients.Postoperatively,the patients were doing well without reintervention for the aortic valve for 8 and 6 years,respectively.Their aortic annular diameter increased along with somatic growth.Bicuspidization for neonates or infancy can be performed safely using the open-sleeve technique as its midterm results have been satisfactory.

Unicuspid Aortic Valve, an Extremely Rare Congenital Anomaly in Adults: A Systemic Review

The most common congenital heart defect is the bicuspid aortic valve (BAV) occurring with fusion of one of the three-valve commissures. A rarer valvular phenomenon is the unicuspid aortic valve (UAV) which has an estimated prevalence of 0.02% in the adult population. Two morphologic subtypes of UAV exist: the earlier presenting, acommissural UAV and the later appearing unicommissural. To better characterize and manage patients with UAVs, a systematic review of this rare phenomenon was performed. The objective of our study was to conduct a systematic review of adequate case studies involving UAV patients to describe patient characteristics, clinical presentation, management, and common sequela featured there within. The mean age of presentation in this review was 35.6 years. When diagnosing UAV, TEE was the most utilized diagnostic modality (65%) followed by intraoperative diagnosis (17%) discovered with valve repair or incidentally during another procedure. TTE was utilized to diagnose only 7% of the cases reviewed likely owing to the difficulty and inaccuracies in identifying UAV with this method that were previously established by multiple series. Interventional options for UAV are balloon versus surgical valvotomy, aortic valve replacement, Ross procedure and aortic root replacement. They are performed on an individual basis and all cases ultimately require aortic valve replacement (AVR) or Ross procedure (to avoid anticoagulation). Aortic root replacement is additionally required if aortic root/ascending aorta diameter exceeds 4.5 cm. In this review, Aortic aneurysm (16%) cases resulted in surgical interventions. There may be a need to implant permanent pacemaker (in 3% - 8%) during AVR when calcified UAV has calcification extending into interventricular septum.

Ascending aortic dilatation rate after transcatheter aortic valve replacement in patients with bicuspid and tricuspid aortic stenosis: A multidetector computed tomography follow-up study

BACKGROUND: Current data is lacking about the progression of ascending aortic dilatation after transcatheter aortic valve replacement(TAVR) in aortic stenosis(AS) patients with bicuspid aortic valve(BAV) and tricuspid aortic valve(TAV). This study aims to assess the ascending aortic dilatation rate(mm/year) after TAVR in patients with BAV versus TAV using a multidetector computed tomography(MDCT) fol ow-up and to determine the predictors of ascending aortic dilatation rate.METHODS: Severe AS patients undergoing TAVR from March 2013 to March 2018 at our center with MDCT follow-ups were included. BAV and TAV were identified using baseline MDCT. Baseline and follow-up MDCT images were analyzed,and the diameters of ascending aorta were measured. Study end point is ascending aortic dilatation rate(mm/year). Furthermore,factors predicting ascending aortic dilatation rate were also investigated.RESULTS: Two hundred and eight patients were included,comprised of 86 BAV and 122 TAV patients. Five,4,3,2,and 1-year MDCT follow-ups were achieved in 7,9,30,46,and 116 patients. The ascending aortic diameter was significantly increased after TAVR in both BAV group(43.7±4.4 mm vs. 44.0±4.5 mm;P<0.001) and TAV group(39.1±4.8 mm vs. 39.7±5.1 mm;P<0.001). However,no difference of ascending aortic dilatation rate was found between BAV and TAV group(0.2±0.8 mm/year vs. 0.3±0.8 mm/year,P=0.592). Multivariate linear regression revealed paravalvular leakage(PVL) grade was independently associated with ascending aortic dilatation rate in the whole population and BAV group,but not TAV group. No aortic events occurred during follow-ups.CONCLUSION: Ascending aortic size continues to grow after TAVR in BAV patients,but the dilatation rate is mild and comparable to that of TAV patients. PVL grade is associated with ascending aortic dilatation rate in BAV patients post-TAVR.

Bicuspid aortic valve hemodynamics does not promote remodeling in porcine aortic wall concavity

AIM: To investigate the role of type-I left-right bicuspid aortic valve(LR-BAV) hemodynamic stresses in the remodeling of the thoracic ascending aorta(AA) concavity, in the absence of underlying genetic or structural defects.METHODS: Transient wall shear stress(WSS) profiles in the concavity of tricuspid aortic valve(TAV) and LR-BAV AAs were obtained computationally. Tissue specimens excised from the concavity of normal(nondilated) porcine AAs were subjected for 48 h to those stress environments using a shear stress bioreactor. Tissue remodeling was characterized in terms of matrix metalloproteinase(MMP) expression and activity via immunostaining and gelatin zymography.RESULTS: Immunostaining semi-quantification results indicated no significant difference in MMP-2 and MMP-9 expression between the tissue groups exposed to TAV and LR-BAV AA WSS(P = 0.80 and P = 0.19, respectively). Zymography densitometry revealed no difference in MMP-2 activity(total activity, active form and latent form) between the groups subjected to TAV AA and LR-BAV AA WSS(P = 0.08, P = 0.15 and P = 0.59, respectively).CONCLUSION: The hemodynamic stress environment present in the concavity of type-I LR-BAV AA does not cause any significant change in proteolytic enzyme expression and activity as compared to that present in the TAV AA.

Effect of Bicuspid Aortic Valve Cusp Fusion on Aorta Wall Shear Stress: Preliminary Computational Assessment and Implication for Aortic Dilation

The bicuspid aortic valve (BAV) is a major congenital valvular abnormality and is associated with a high prevalence of aortic dilation, whose expression depends on the type of leaflet fusion. Although BAV hemodynamics is considered a potential pathogenic contributor, the impact of BAV fusion on ascending aorta (AA) wall shear stress (WSS) remains largely unknown. A fluid-structure interaction approach was implemented to predict the hemodynamics and WSS characteristics in realistic AA models subjected to the flow of a normal tricuspid aortic valve (TAV) and three BAV morphotypes (left-right coronary cusp fusion (LR), right-non coronary cusp fusion (RN) and non-left coronary cusp fusion (NL)). TAV flow conditions subjected the proximal and middle AA to a streamlined flow typical of flows in bends, while BAV flow conditions generated increased flow helicity. The LR-BAV orifice jet generated flow abnormalities primarily in the proximal AA, which were marked by a uniform WSS overload along the wall circumference and contrasted WSS directionalities on the wall convexity and concavity. Flow abnormalities generated by the RN-BAV and NL-BAV inlet flow conditions were more diffuse and consisted of WSS overloads in the convexity of the proximal and middle AA and contrasted WSS directionalities in the anterior and posterior wall regions. This study demonstrates the impact of the BAV morphotype on AA hemodynamics and provides quantitative evidence for the existence of WSS abnormalities in aortic wall regions prone to dilation.

The Impact of a Bicuspid Aortic Valve on Aortic Geometry and Function in Patients with Aortic Coarctation:A Comprehensive CMR Study

Background:An isolated bicuspid aortic valve(BAV)is associated with structural and functional abnormalities of the aorta and the left ventricle(LV).Although~50%of patients with aortic coarctation(CoA)have a BAV,less is known about its impact on LV function and aortic geometry and function in CoA patients.In this cardiovascular magnetic resonance imaging(CMR)study,we analysed markers of LV and aortic function as well as aortic geometry in a large cohort of CoA patients with a BAVand compared them with CoA patients with a tricuspid aortic valve(TAV).Methods:We included 48 patients with a BAV(18.4±9.3 years)and 45 patients with TAV(20.7±9.9 years).LV volumes,mass and ejection fraction as well as aortic distensibilty,pulse wave velocity(PWV)were measured from standard cine CMR and phase-contrast CMR images.2-dimensional CMR feature tracking(2DCMR-FT)was performed to measure longitudinal,circumferential and radial strain and strain rate of the LV.Aortic arch geometry was classified as romanic,gothic and crenel.Results:LV volumes,mass and ejection fraction as well as aortic distensibility and PWV did not significantly differ between the BAV and the TAV group.There was also no significant difference for LV global longitudinal,radial and circumferential strain and strain rate between both groups.Patients with a BAV had more commonly a gothic aortic arch compared to TAV patients,but this difference was not statistically significant(22 vs.14,p=0.2).Ascending and descending aortic distensibility correlated with LV mass in the entire patient group(p<0.001).Global longitudinal,circumferential and radial strain(GLS,GCS,GRS)and global longitudinal and circumferential strain rate(GLSR,GCSR)correlated with LV ejection fraction(p<0.001).Conclusion:Our data suggest that the presence of a BAV does not adversely impact LV and aortic function in children and young adults with CoA.The correlation of global circumferential,longitudinal and radial strain values with LV ejection fraction demonstrates that 2D-CMR-FT might provide additional information related to ventricular function in CoA patients.

Aortic Valve Replacement in Bicuspid Aortic Valve with a Single Coronary Artery

Coronary artery anomalies combined with bicuspid aortic valve are rare but cause perioperative complications if not detected on time. Because anomalous coronary arteries vary with respect to the ostium’s origin and transverse route, the precise anatomy should be identified preoperatively and the procedure modified. We describe a severely stenotic bicuspid aortic valve and anomalous coronary artery corrected successfully with a modified valve replacement procedure, illustrating the importance of analyzing coronary anatomy preoperatively, regardless of age, to avoid occluding an anomalous artery’s ostium and to address the anomalies. We describe our modified procedure based on the artery’s location for a safe operation.

Infective bicuspid aortic valve endocarditis causing acute severe regurgitation and heart failure:A case report

BACKGROUND Infective endocarditis(IE)is an uncommon but potentially life-threatening infection,which occasionally develops into acute severe valve insufficiency leading to the onset of heart failure,and necessitates timely intervention.However,the variable and atypical clinical manifestations always make the early detection of IE difficult and challenging.CASE SUMMARY A 45-year-old female who was previously healthy presented with exertional shortness of breath and paroxysmal nocturnal dyspnea.She also suffered from a significant decrease in exercise capacity,whereas her body temperature was normal.She had severe hypoxemia and hypotension along with a marked aortic valve murmur.Diffuse pulmonary edema and bilateral pleural effusion were observed on both chest X-ray and computed tomography scan.Transthoracic echocardiography was performed immediately and revealed severe regurgitation of the bicuspid aortic valve.Transesophageal echocardiography was further performed and vegetations were detected.In addition to adequate medical therapy and ventilation support,the patient underwent urgent and successful aortic valve replacement.Her symptoms were significantly relieved and the postoperative chest X-ray showed that pulmonary edema was significantly reduced.Histopathology of the resected valve and positive microorganism culture of the surgical specimen provided evidence of definite IE.CONCLUSION IE should be considered in critical patients with refractory heart failure caused by severe bicuspid aortic valve regurgitation.

Expect the Unexpected: A Unique Association of Bicuspid Aortic Valve, with Severe Aortic Stenosis and Dilation of Ascending Aorta, with Cervical Vagus Nerve Schwannoma

Hoarseness of voice is a common symptom of many laryngeal and extralaryngeal conditions. It is very crucial to identify the culprit behind it, keeping in mind all the various differentials. We re-port a case of a 35-year-old woman presenting with complaint of hoarseness of voice. Upon car-diac evaluation, the patient was diagnosed with bicuspid aortic valve, with severe aortic stenosis and dilation of ascending aorta. We suspected that the plausible reason for hoarseness of voice was compression of recurrent laryngeal nerve due to dilation of aorta, i.e., Ortner’s syndrome. But to our surprise, CT of aorta and neck revealed extensive elongated cervical vagus nerve schwannoma. Such type of association is unique and new to voluminous medical literature.

Physical Stress Echocardiography Evaluation in Athletes with Bicuspid Aortic Valves

Objective: Bicuspid Aortic Valve (BAV) is normally asymptomatic for a long time in both the general population and regularlytrained athletes. The study aimed to evaluate the role of physical stress echocardiography in early identification of any possible dissimilarities in the Left Ventricle (LV) performance and the valve functioning of asymptomatic BAV athletes as compared to the Tricuspid Aortic Valve (TAV) athletes. Design: Data were collected for BAV and TAV athletes from echocardographic examinations to evaluate any possible differences between them. Setting: Sport Medicine Center University of FlorenceItaly. Participants: 66 male BAV athletes and 45 TAV athletes Assessment of risk factors: decrease in LV performance and aortic valve dysfunction during stress test. Main outcome measures: Measure of the standard echocardiographic parameters. Comparison of LV Ejection Fraction (EF) and Aortic Peak Flow Velocity (APFV) data in the two groups at rest and after stress. Results: At rest, values were normal in both groups, although LV systolic diameters tended to be higher in BAV. After physical effort, APFV and EF showed a significant increase in both groups, and for the former the values were at the upper limits in BAV (2.55 m/s BAV 2.12 m/s TAV). Conclusions: The data confirm normal LV performance in asymptomatic BAV athletes. Considering the tendency of this group to show slight enhancement of both APFV and LV dimensions in this group periodical evaluation with physical stress echography might be proposed as a followup procedure for early detection of any additional effect of physical exercise.

Modified Ross Procedure for a Young Woman with a Root Abscess on a Bicuspid Aortic Valve: Report of a Case

A 19-year-old woman with a bicuspid aortic valve was admitted because of active infective endocarditis with a root abscess. Four weeks of antibiotic therapy achieved negative blood cultures and normalized inflammatory signs;however, echocardiography revealed severe aortic regurgitation through an abscess cavity located at the root. The modified Ross procedure, in which the pulmonary autograft was reinforced with a prosthetic graft to prevent postoperative annular dilation, was successfully performed. The postoperative clinical course was uneventful, and echocardiography performed at 1 year showed trivial aortic regurgitation. Selection of homograft may benefit young woman who wishes to bear children, and covering pulmonary autograft by a prosthetic graft in order to prevent annular dilatation of autograft in patient with bicuspid aortic valve, may be allowed only under negative infection sign.

Prevalence of Bicuspid Aortic Valve in Turner Syndrome Patients Receiving Cardiac MRI and CT: A Meta-Analysis

Turner syndrome(TS)is a rare disorder affecting 25–50 in 100000 female newborns.Bicuspid aortic valve(BAV)is assumed to be the most common congenital heart defect(CHD)in TS.In literature,reported BAV prevalence in TS ranges between 14%and 34%.The specific BAV prevalence in TS is still unknown.The aim of this study was to give a more precise estimation of BAV prevalence in TS by conducting a meta-analysis of TS-studies,which detected BAV by either cardiac magnetic resonance imaging(MRI)or cardiac computed tomography(CT).We searched PubMed,Cochrane Library,and Web of Science databases to collect observational studies including the prevalence of BAV identified by cardiac MRI or cardiac CT in TS patients up to June 4th,2021.After screening for inclusion,data extraction,and quality assessment by two independent reviewers,the meta-analysis was performed with R 4.1.1 software.Results are shown as proportion and weighted mean difference with 95%confidence intervals(95%CI).In total,11 studies involving 1177 patients were included.Pooled data showed that the prevalence of BAV in TS patients was 23.7%(95%CI:21.3%to 26.1%).No high heterogeneity was found between the included studies.The current meta-analysis reveals that BAVcan be detected in 23.7%of TS patients receiving cardiac MRI or cardiac CT.Therefore,BAV can be considered as the most common CHD in TS.Compared to TTE,cardiac MRI and cardiac CT might represent superior imaging modalities in BAV assessment of adult TS patients.

High-Risk Congenital Coronary Abnormalities in Patients with Bicuspid Aortic Valve

Objective:Abnormal coronary artery origin(ACAO)from the opposite sinus with inter-arterial course of the ectopic proximal vessel is associated with the greatest potential for clinical manifestations,specifically sudden death.Data remain limited regarding the association between bicuspid aortic valve(BAV)and this potentially dangerous coronary variant reported in up to 0.6%in the general population.We investigated the frequency of this high-risk ACAO with inter-arterial course in our surgical series of BAV patients.Methods and Results:We conducted a retrospective study to identify BAV patients with ACAO and inter-arterial course who underwent elective aortic valve/root surgery between 2010 and 2019 in our tertiary center.A total of 279 consecutive patients with BAV were identified.Among these,four patients(1.4%)had ACAO with inter-arterial course.Three patients had abnormal right coronary artery arising from the theoretical opposite coronary sinus with intramural course.The fourth patient presented an abnormal left coronary artery from a single coronary artery arising from the theoretical right coronary sinus with a long inter-arterial course.Conclusion:Our results from a single-center experience support high-risk ACAOS may be more frequently diagnosed in BAV patients,especially in surgical series,justifying a careful preoperative assessment.

Bicuspid Aortic Valve Disease in Turner Syndrome: A Meta-Analysis of Prevalence

Turner syndrome patients partially or completely lack the X chromosome. 1 - 2500 female live births are affected. Clinical features include webbed neck, short stature, broad chest etc. Bicuspid aortic valve disease (BAV) occurs in more than 30% of Turner syndrome patients causing significant morbidity and mortality. We aimed to establish a more reliable estimate of the prevalence of BAV in Turner syndrome. PubMed, Embase and PsycINFO databases were searched until 2022. Review Manager (RevMan 5.4.1) and the JASP software (0.16.00) were used for meta-analysis. 15 studies with a total of 3189 patients were combined. The pooled prevalence of BAV in Turner syndrome was 22.0% (95% CI: 15.0% - 29.0%). Sub group analysis by 45, X0 karyotype and age had prevalence of 24.0% and 8% respectively. The studies had high heterogeneity and possible publication biases. In summary, the study established that the prevalence of BAV in Turner syndrome patients diagnosed by echocardiogram, CT and MRI scans, is 22.0%, and 24% in patients with true monosomy 45, X0 karyotypes. Routine BAV exam should pay particular attention to monosomy 45, X0 karyotype patients, and where possible, CT and MRI should always accompany echocardiography for BAV screening, especially for pediatrics.

Acquired Gerbode Defect Secondary to Severe Bicuspid Aortic Valve Endocarditis

An annular aortic abscess is a fatal complication of infective endocarditis. Echocardiography is the initial imaging modality to confirm the diagnosis in suspected infective endocarditis. Here, we present a case of a bicuspid aortic valve infective endocarditis caused by Staphylococcus aureus and complicated with annular aortic abscess resulting in acquired Gerbode defect (type II) with tricuspid valve vegetation which was undiagnosed preoperatively. The intraoperative transoesophageal echocardiography yields a new finding prior to the surgical incision, which impacted the clinical decision-making and increased the burden of the procedure.

Trans-Frame Aortic Regurgitation of New-Generation Aortic Bioprosthesis

A widely used aortic valve bioprosthesis is susceptible to regurgitation between the sewing ring and the frame of the valve due to its relatively thin fabric coverage. In some cases this leak has been shown to resolve with administration of protamine, however, tension on this area from annular sutures placed in an asymmetric bicuspid valve annulus may exacerbate the defect.

Native Aortic Valve Endocarditis—A Case Report

Introduction: To report a case of isolated “endocarditic” aortic regurgitation in a 17-year old female with infective vegetations on aortic valve. Case Report: A 17-year old female was admitted with features of heart failure and a febrile illness. Blood cultures were negative and ECG revealed normal. Echocardiography revealed a “kissing-type” of vegetation on the bicuspid aortic valve with severe aortic regurgitation and a dilated left ventricle with moderate dysfunction. Conclusion: The management of aortic insufficiency occurring in infective endocarditis may differ and the presence of intractable pulmonary edema or shock is a clear indication for prompt valve replacement. The traditional diagnostic criteria are insufficient to diagnose infective endocarditis and the modified Duke criteria provide high sensitivity and specificity over 80% for the diagnosis of native valve endocarditis with positive blood cultures.