Fluid Structural Interaction of a Patient Specific Congenital Bicuspid Aortic Valve

2012 ◽  
Author(s):  
V. Govindarajan ◽  
H. S. Udaykumar ◽  
S. Vigmostad ◽  
M. M. Levack ◽  
J. H. Gorman ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Bicuspid Aortic Valve ◽  
Aortic Root ◽  
Aortic Aneurysms ◽  
Patient Specific ◽  
Aortic Dilatation ◽  
Structural Interaction ◽  
Aortic Pathology ◽  
Specific Geometry ◽  
Opening Phase

Congenital Bicuspid Aortic Valve (BAV) is a valvular anomaly where a patient is born with a valve with two leaflets instead of a normal tri-leaflet valve. It has also been reported that BAVs are prone to progressive calcification and also other complications such as ascending aortic dilatation, dissection and rupture [1]. The geometrical variations with the BAV may be a factor in altering the deformation and stresses on the leaflets resulting in calcification of the leaflets earlier than with normal tri-leaflet aortic valves. Altered flow patterns past BAV into the ascending aorta can also be anticipated. Analysis of flow dynamics during the opening phase, and the resultant fluid forces on the aortic root could improve our understanding of aortic aneurysms and dissections observed in patients with BAV [2]. In this study, the valvular deformation and the flow across a patient-specific BAV and root are simulated using the method of fluid structural interaction analysis. The patient-specific geometry is obtained employing 3D ultrasound images segmented as point cloud data and surfaces are constructed with commercial software GAMBIT using NURBS based connectivity. The opening phase of the valve is simulated under flow with physiological Reynolds number and with realistic material properties for the leaflets and the aortic root. Such an analysis on the dynamics of BAV with patient-specific geometry may be a useful tool in stratifying BAV patients that may be at risk in developing valvular and ascending aortic pathology.

scholarly journals Bicuspid Aortic Valve Disease and Ascending Aortic Aneurysms: Gaps in Knowledge

2012 ◽  
Vol 2012 ◽  
pp. 1-16 ◽  
Author(s):  
Katie L. Losenno ◽  
Robert L. Goodman ◽  
Michael W. A. Chu
Keyword(s):  
Aortic Valve ◽  
Bicuspid Aortic Valve ◽  
Aortic Valve Disease ◽  
Aortic Aneurysms ◽  
Valve Disease ◽  
Cardiac Anomaly ◽  
Aortic Dilatation ◽  
Congenital Cardiac Anomaly ◽  
Valvular Stenosis ◽  
Ongoing Surveillance

The bicuspid aortic valve is the most common congenital cardiac anomaly in developed nations. The abnormal bicuspid morphology of the aortic valve results in valvular dysfunction and subsequent hemodynamic derangements. However, the clinical presentation of bicuspid aortic valve disease remains quite heterogeneous with patients presenting from infancy to late adulthood with variable degrees of valvular stenosis and insufficiency and associated abnormalities including aortic coarctation, hypoplastic left heart structures, and ascending aortic dilatation. Emerging evidence suggests that the heterogeneous presentation of bicuspid aortic valve phenotypes may be a more complex matter related to congenital, genetic, and/or connective tissue abnormalities. Optimal management of patients with BAV disease and associated ascending aortic aneurysms often requires a thoughtful approach, carefully assessing various risk factors of the aortic valve and the aorta and discerning individual indications for ongoing surveillance, medical management, and operative intervention. We review current concepts of anatomic classification, pathophysiology, natural history, and clinical management of bicuspid aortic valve disease with associated ascending aortic aneurysms.

Abstract 2069: Aortic Valve Replacement In Patients With Bicuspid Aortic Valve Disease Is Not Followed By Progressive Aortic Dilatation: A 15-year Study

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Ayyaz Ali ◽  
Amit Patel ◽  
Darren Freed ◽  
Yasir Abu-Omar ◽  
Ahmad Y Sheikh ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Bicuspid Aortic Valve ◽  
Aortic Valve Disease ◽  
Valve Disease ◽  
Aortic Diameter ◽  
Implantation Technique ◽  
Aortic Dilatation ◽  
Aortic Pathology ◽  
Ascending Aortic Diameter

Objectives A bicuspid aortic valve may be associated with an aortopathy, this may lead to progressive aortic dilatation over time. It is uncertain whether the ascending aorta should be replaced prophylactically during AVR in these patients. We analyzed change in ascending aortic diameter following AVR, to determine whether a clinically important aortic pathology exists in patients with bicuspid aortic valve disease. Methods Demographic, operative and clinical data were obtained retrospectively through casenote review. AVR was performed using a homograft or porcine stentless valve using the subcoronary implantation technique. Patients were grouped according to whether their native aortic valve was identified as tricuspid (TC) or bicuspid (BC) at operation. Serial transthoracic echocardiograms were analyzed to measure pre-operative and post-operative ascending aortic diameter. Results 217 patients underwent AVR between 1 st January 1991 and 1 st January 2001. Ninety patients had a bicuspid aortic valve, in the remaining 127 the valve was tricuspid. The bicuspid group was younger ( BC 62yr +/− 15, TC 71yr +/− 12 yrs; p < 0.001). Follow-up echocardiography was performed 6.0 +/− 4.3 years post-operatively. Pre-operative ascending aortic diameter was similar (BC 3.2 +/− 0.5, TC 3.2 +/− 0.5 cm; p = 0.56) There was no difference in the increase in ascending aortic diameter over follow-up (BC 0.1 +/− 0.5, TC 0.0 +/− 0.5 cm; p = 0.34) Conclusion The clinical importance of “bicuspid aortopathy” in an older age group appears to be minimal. Additional aortic procedures designed to protect against progressive aortic aneurysmal disease in this setting are not justified.

Abstract 3189: Prevalence of Bicuspid Aortic Valve in Turner Syndrome

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Vandana Sachdev ◽  
Lea Ann Matura ◽  
Stanislav Sidenko ◽  
Vincent Ho ◽  
Andrew Arai ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Turner Syndrome ◽  
Bicuspid Aortic Valve ◽  
Aortic Root ◽  
Ascending Aorta ◽  
Aortic Dilatation ◽  
Aortic Valves ◽  
Number Of Patients ◽  
Valve Structure ◽  
Asymptomatic Individuals

Women with Turner syndrome (TS) have an increased risk of congenital cardiovascular defects. Previous studies have reported a 10 –20% prevalence rate of bicuspid aortic valves and there are increasing reports of a vasculopathy that predisposes patients to aortic dilatation and dissection. This prospective study aimed to characterize aortic valve and aortic root structure in unselected asymptomatic individuals with TS. A total of 253 females aged 7– 67 years with karyotype proven TS were examined. Transthoracic echocardiography revealed a normal tricuspid aortic valve (TAV) in 162, a ‘probable TAV’ in 8 subjects, a bicuspid aortic valve (BAV) in 65 and ‘probable BAV’ in 3 subjects. The aortic valve could not be visualized by echocardiography in 15/253 or 6%. Magnetic resonance imaging (MRI) revealed valve structure in 11/12 of the probable cases (all confirmatory of the ‘probable’ diagnosis) and 12/15 of the non-visualized cases (8 BAV and 4 TAV), so only 3/253 subjects could not be visualized by either modality. The aortic valve was bicuspid in 76 of the 250 adequately imaged subjects (30%). Peak aortic valve flow was higher in BAV subjects (1.72±0.07 vs. 1.90v0.03 m/sec, P=0.0002), with one case of significant aortic stenosis. Among subjects with a BAV, aortic regurgitation was moderate or greater in ∼15%. Aortic diameters at the annulus, sinuses of Valsalva, sinotubular junction and ascending aorta were all significantly greater in the BAV group. Thirty patients in the BAV group (12%) had aortic root diameters that were outside of the 95% normal confidence limits based on Roman nomograms. Ascending aortic diameters by echo and MRI were highly correlated (r=0.77). In summary, echocardiography supplemented with MRI reveals an extraordinarily high prevalence of abnormal aortic valves in asymptomatic subjects with TS. The abnormal valve structure is associated with higher peak flows, evidence of clinically significant valvular dysfunction, and widening of the ascending aorta in a significant number of patients. All girls and women with TS should have careful echocardiographic evaluation upon diagnosis to identify the one in three asymptomatic individuals with an abnormal valve requiring monitoring for aortic root dilatation and valvular dysfunction.

scholarly journals Bicuspid Aortic Valve: Role of Multiple Gene Variants in Influencing the Clinical Phenotype

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Elena Sticchi ◽  
Rosina De Cario ◽  
Alberto Magi ◽  
Sabrina Giglio ◽  
Aldesia Provenzano ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Bicuspid Aortic Valve ◽  
Aortic Root ◽  
Rare Variants ◽  
Aortic Surgery ◽  
Genetic Diagnosis ◽  
Clinical Manifestations ◽  
Aortic Dilatation ◽  
Reduced Penetrance ◽  
Next Generation Sequencing Ngs

Background. Bicuspid aortic valve (BAV) is a common congenital heart defect with increased prevalence of aortic dilatation and dissection. BAV has an autosomal dominant pattern of inheritance with reduced penetrance and variable expressivity. BAV has been described as an isolated trait or associated with other clinical manifestations in syndromic conditions. Identification of a syndromic condition in a BAV patient is clinically relevant in order to personalize indication to aortic surgery. We aimed to point out how genetic diagnosis by next-generation sequencing (NGS) can improve management of a patient with complex BAV clinical picture. Methods and Results. We describe a 45-year-old Caucasian male with BAV, thoracic aortic root and ascending aorta dilatation, and connective features evocative but inconclusive for clinical diagnosis of Marfan syndrome (MFS). Targeted (91 genes) NGS was used. Proband genetic variants were investigated in first-degree relatives. Proband carried 5 rare variants in 4 genes: FBN1(p.Asn542Ser and p.Lys2460Arg), NOTCH1(p.Val1739Met), LTBP1(p.Arg1330Gln), and TGFBR3(p.Arg423Trp). The two FBN1 variants were inherited in cis by the mother, showing systemic features evocative of MFS, but with a milder phenotype than that observed in the proband. Careful clinical observation along with the presence of the FBN1 variants allowed diagnosis of MFS in the proband and in his mother. NOTCH1 variant was found in mother and brother, not exhibiting BAV, thus not definitely supporting/excluding association with BAV. Interestingly, the proband, his brother and father, all showing root dilatation, and his sister, with upper range aortic root dimension, were carriers of a TGFBR3 variant. LTBP1 might also modulate the vascular phenotype. Conclusions. Our results underline the usefulness of NGS together with family evaluation in diagnosis of patients with monogenic traits and overlapping clinical manifestations due to contribution of the same genes and/or presence of comorbidities determined by different genes.

Ascending aorta mechanics in bicuspid aortopathy: controversy or fact?

2020 ◽  
pp. 021849232092873
Author(s):  
Dimitrios C Iliopoulos ◽  
Dimitrios P Sokolis
Keyword(s):  
Mechanical Properties ◽  
Aortic Valve ◽  
Bicuspid Aortic Valve ◽  
Ascending Aorta ◽  
Aortic Aneurysms ◽  
Aortic Dilatation ◽  
Aged Patients ◽  
Thoracic Aortic Aneurysms ◽  
Maximal Diameter ◽  
Sole Criterion

Bicuspid aortic valve is the most common congenital cardiovascular defect, often associated with proximal aortic dilatation, and the ideal management strategy is debated. The inconsistency in previous and present guideline recommendations emphasizes the insufficiency of the maximal diameter as the sole criterion for prophylactic repair. Our ability to guide clinical decisions may improve through an understanding of the mechanical properties of ascending thoracic aortic aneurysms in bicuspid compared to tricuspid aortic valve patients and non-aneurysmal aortas, because dissection and rupture are aortic wall mechanical failures. Such an understanding of the mechanical properties has been attempted by several authors, and this article addresses whether there is a controversy in the accumulated knowledge. The available mechanical studies are briefly reviewed, discussing factors such as age, sex, and the region of mechanical examination that may be responsible for the lack of unanimity in the reported findings. The rationale for acquiring layer-specific properties is presented along with the main results from our recent study. No mechanical vulnerability of ascending thoracic aortic aneurysms was evidenced in bicuspid aortic valve patients, corroborating present conservative guidelines concerning the management of bicuspid aortopathy. Weakening and additional vulnerability was evidenced in aged patients and those with coexisting valve pathology, aortic root dilatation, hypertension, and hyperlipidemia. Discussion of these results from age- and sex-matched subjects, accounting for the region- and layer-specific aortic heterogeneity, in relation to intact wall results and histologic confirmation, helps to reconcile previous findings and affords a universal interpretation of ascending aorta mechanics in bicuspid aortopathy.

Abstract 15097: Altered TGFβ Signalling Effector Molecules Contribute to Bicuspid Aortic Valve-associated Thoracic Aortopathy

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Candice L Dilworth ◽  
Francesca Sadnick ◽  
Sari Padang ◽  
Yaxin Lu ◽  
Elizabeth N Robertson ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Bicuspid Aortic Valve ◽  
Aortic Aneurysms ◽  
Extra Cellular Matrix ◽  
Matrix Metalloproteinase 2 ◽  
Compensatory Mechanism ◽  
Aortic Dilatation ◽  
Matrix Degradation ◽  
Tgfβ Signalling ◽  
Cellular Matrix

Upregulated TGFβ signalling plays a key role in mediating congenital thoracic aortic aneurysms (TAA), and has been implicated in bicuspid aortic valve-associated TAA (BAV-TAA). TGFβ is normally stored within the extra-cellular matrix via sequestration proteins bound to the microfibrillar protein, fibrillin. TGFβ is released in response to changes in these sequestration proteins, allowing TGFβ to exert its signalling effects. We hypothesised that in BAV-TAA the upregulation of TGFβ signalling will pathologically alter effector molecule expression, causing matrix degradation and altered TGFβ sequestration. Immunohistochemistry was used to quantify protein expression in aortic tissue from 8 human BAV-TAA and 6 normal controls. In BAV-TAA, TGFβ expression was elevated in all layers (2.5:1; p<0.05), particularly in the adventitia (3.4:1; p<0.001). Microfibril-associated glycoprotein-1 (MAGP-1), which promotes TGFβ release, was elevated (2:1; p<0.03), while latent TGFβ binding protein-1 (LTBP-1), which promotes TGFβ sequestration, was decreased (0.3:1; p=0.03). Matrix metalloproteinase-2 (MMP-2) and MMP-9 expression was elevated (2.6:1; p<0.005, 1.5:1; p<0.05, respectively), and MMP-3 expression was decreased (0.5:1; p<0.05). Fibrillin-1 expression was not altered. The observed changes in TGFβ sequestration proteins will increase unbound TGFβ, leading to upregulation of downstream signalling. The elevated levels of MMP-2 and MMP-9 mediate pathological matrix remodelling, leading to aortic dilatation. The paradoxical decrease in MMP-3 may represent a compensatory mechanism that attempts to reduce overall pathological MMP activity, in order to limit damage to the aortic wall. In conclusion, in BAV-TAA excessive TGFβ signalling is potentiated by reduced TGFβ sequestration, causing extra-cellular matrix degradation by MMPs. This supports the rationale for the use of angiotensin II receptor blockers in BAV-TAA.

Aortic assessment of bicuspid aortic valve patients and their first-degree relatives

2017 ◽  
Vol 25 (3) ◽  
pp. 192-198
Author(s):  
Pablo Straneo ◽  
Gabriel Parma ◽  
Natalia Lluberas ◽  
Alvaro Marichal ◽  
Gerardo Soca ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Endothelial Function ◽  
Bicuspid Aortic Valve ◽  
Aortic Root ◽  
Inverse Correlation ◽  
Hereditary Disease ◽  
Root Diameter ◽  
Aortic Dilatation ◽  
First Degree Relatives ◽  
Increased Risk

Background Bicuspid aortic valve patients have an increased risk of aortic dilatation. A deficit of nitric oxide synthase has been proposed as the causative factor. No correlation between flow-mediated dilation and aortic diameter has been performed in patients with bicuspid aortic valves and normal aortic diameters. Being a hereditary disease, we compared echocardiographic features and endothelial function in these patients and their first-degree relatives. Methods Comprehensive physical examinations, routine laboratory tests, transthoracic echocardiography, and measurements of endothelium-dependent and non-dependent flow-mediated vasodilatation were performed in 18 bicuspid aortic valve patients (14 type 1 and 4 type 2) and 19 of their first-degree relatives. Results The first-degree relatives were younger (36.7 ± 18.8 vs. 50.5 ± 13.9 years, p = 0.019) with higher ejection fractions (64.6% ± 1.7% vs. 58.4% ± 9.5%, p = 0.015). Aortic diameters indexed to body surface area were similar in both groups, the except the tubular aorta which was larger in bicuspid aortic valve patients (19.3 ± 2.7 vs. 17.4 ± 2.2 mm·m−2, p = 0.033). Flow-dependent vasodilation was similar in both groups. A significant inverse correlation was found between non-flow-dependent vasodilation and aortic root diameter in patients with bicuspid aortic valve ( R = −0.57, p = 0.05). Conclusions Bicuspid aortic valve patients without aortopathy have larger ascending aortic diameters than their first-degree relatives. Endothelial function is similar in both groups, and there is no correlation with ascending aorta diameter. Nonetheless, an inverse correlation exists between non-endothelial-dependent dilation and aortic root diameter in bicuspid aortic valve patients.

Bicuspid aortic valve and aortopathy: novel prognostic predictors for the identification of high-risk patients

2020 ◽  
Author(s):  
Luca Longobardo ◽  
Scipione Carerj ◽  
Alessandra Bitto ◽  
Maurizio Cusmà-Piccione ◽  
Maria Ludovica Carerj ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Surgical Treatment ◽  
Aortic Valve ◽  
Bicuspid Aortic Valve ◽  
Primary Endpoint ◽  
Cox Regression ◽  
Aortic Surgery ◽  
Aortic Aneurysms ◽  
Aortic Dilatation ◽  
Cox Regression Analysis

Abstract Aims Bicuspid aortic valve (BAV) may be complicated by aortic aneurysms and dissection. This study aimed to evaluate the prognostic efficacy of markers from cardiac imaging, as well as genetic and new biomarkers, to early predict aortic complications. Methods and results We re-evaluated after a mean time of 48 ± 11 months 47 BAV patients who had undergone previous echocardiography for evaluation of aortic stiffness and 2D aortic longitudinal strain (LS) (by speckle-tracking analysis), and who had given a blood sample for the assessment of a single-nucleotide polymorphism of elastin gene (ELN rs2 071307) and quantification of elastin soluble fragments (ESF). Surgical treatment of aortic aneurysm/dissection was the primary endpoint, and an aortic dimension increase (of one or more aortic segments) ≥1 mm/year was the secondary endpoint. Nine patients underwent surgical treatment of ascending aorta (AA) aneurysms. Out of the 38 patients who did not need surgical intervention, 16 showed an increase of aortic root and/or AA dimension ≥1 mm/year. At multivariate Cox regression analysis, an impaired AA LS was an independent predictor of aortic surgery [P = 0.04; hazard ratio (HR) 0.961; 95% confidence interval (CI) 0.924–0.984] and aortic dilatation (P = 0.007; HR 0.960; 95% CI 0.932–0.989). An increased quantity of ESF was correlated (P = 0.015) with the primary endpoint at univariate Cox regression analysis but it did not keep statistical significance at multivariate analysis. Conclusion In BAV patients, impairment of elastic properties of the AA, as assessed by 2D LS, is an effective predictor of aortic complications.

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