Subaortic Membrane and Aorto-Septal Angle

Barboza, Laura; Garcia, Flor; Barnoya, Joaquín; León-Wyss, Juan; Castañeda, Aldo R.

doi:10.1177/2150135113485760

Cited by 12 publications

(5 citation statements)

References 19 publications

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“…It should be noted that visually, this variation in the angle is not very large, as demonstrated in Figure 6. Our results are in agreement with previous studies, reporting the normal LVOT angle range in adults to be between 126 and 144 degrees [10], and between 122 and 135 degrees [11], albeit with somewhat different methodology. This difference in methodology makes it difficult to compare the LVOT angle mea ured in adults to that in fetuses.…”

Section: Discussionsupporting

confidence: 93%

“…Our results also revealed that the LVOT angle of patients with AS was more obtuse than found in normal fetuses. This trend was similar to the results reported for an adult population with subaortic membranes compared to normal controls, ~127° vs. 137°, respectively [ 10 ]. AS may be caused by abnormal aortic valve or subaortic stenosis.…”

Section: Discussionsupporting

confidence: 90%

“…The results from 25 healthy participants gave a mean of 126 ± 6 degrees, while the mean angle in 160 patients with hypertrophic cardiomyopathy was 113 ± 12 degrees. A further study has compared the LVOT angle in 113 adult patients with a sub aortic membrane and 113 matched controls [ 10 ]. The angle was measured from the septum to a line draw in the middle of the aorta rather than at the border as we did.…”

Section: Discussionmentioning

confidence: 99%

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Can Fetal Echocardiographic Measurements of the Left Ventricular Outflow Tract Angle Detect Fetuses with Conotruncal Cardiac Anomalies?

et al. 2021

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Objectives: The angle between the inter-ventricular septum and the ascending aorta can be measured during a sonographic fetal survey while viewing the left ventricular outflow tract (LVOT angle). Our aim was to compare the LVOT angle between fetuses with and without conotruncal cardiac anomaliesrmations. Methods: In this prospective observational study, we compared the LVOT angle between normal fetuses, at different gestational age, and fetuses with cardiac malformations. Results: The study included 302 fetuses screened at gestational age of 12–39 weeks. The LVOT angle ranged from 127 to 163 degrees (mean 148.2), in 293 fetuses with normal hearts, and was not correlated with gestational age. The LVOT angle was significantly wider in fetuses with D-transposition of the great arteries (D-TGA, eight fetuses) and valvar aortic stenosis (AS, three fetuses), than in fetuses with normal hearts (164.8 ± 5.0 vs. 148.2 ± 5.4, respectively, p < 0.001). Conversely, the LVOT angle was significantly narrower in fetuses with complete atrioventricular canal defect (AVC, eight fetuses), than in fetuses with normal hearts (124.8 ± 2.4 vs. 148.2 ± 5.4, respectively, p < 0.001). On ROC analysis, an angle of 159.6 degrees or higher had a sensitivity of 100% and a specificity of 97.3% for the detection of TGA or AS, whereas an angle of 128.8 degrees or lower had a sensitivity of 100% and a specificity of 99.7% for the detection of AVC defect. Conclusions: The LVOT angle is constant during pregnancy, and differs significantly in fetuses with TGA/AS, and AVC, compared to fetuses with normal hearts (wider and narrower, respectively).

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Section: Discussionsupporting

confidence: 93%

Section: Discussionsupporting

confidence: 90%

Section: Discussionmentioning

confidence: 99%

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Can Fetal Echocardiographic Measurements of the Left Ventricular Outflow Tract Angle Detect Fetuses with Conotruncal Cardiac Anomalies?

et al. 2021

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“…Risk factors promoting initial occurrence include morphological LVOT abnormalities such as sharp aortoseptal angle (AoSA), subphysiologic aortic annulus diameter, and large aortic valve-mitral valve separation distance ( 12 , 16 , 20 , 21 ). Recurrence, which occurs in 8–34% of patients over a 10 year period ( 12 , 22 – 27 ), has been associated with young age at both initial diagnosis and surgical intervention, smaller aortic annulus, proximity of the obstruction to the aortic valve, and a higher preoperative peak LVOT gradient ( 4 , 14 , 16 , 25 ).…”

Section: Clinical Presentationmentioning

confidence: 99%

Discrete Subaortic Stenosis: Perspective Roadmap to a Complex Disease

Massé

Shar

Brown

et al. 2018

Front. Cardiovasc. Med.

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Discrete subaortic stenosis (DSS) is a congenital heart disease that results in the formation of a fibro-membranous tissue, causing an increased pressure gradient in the left ventricular outflow tract (LVOT). While surgical resection of the membrane has shown some success in eliminating the obstruction, it poses significant risks associated with anesthesia, sternotomy, and heart bypass, and it remains associated with a high rate of recurrence. Although a genetic etiology had been initially proposed, the association between DSS and left ventricle (LV) geometrical abnormalities has provided more support to a hemodynamic etiology by which congenital or post-surgical LVOT geometric derangements could generate abnormal shear forces on the septal wall, triggering in turn a fibrotic response. Validating this hypothetical etiology and understanding the mechanobiological processes by which altered shear forces induce fibrosis in the LVOT are major knowledge gaps. This perspective paper describes the current state of knowledge of DSS, articulates the research needs to yield mechanistic insights into a significant pathologic process that is poorly understood, and proposes several strategies aimed at elucidating the potential mechanobiological synergies responsible for DSS pathogenesis. The proposed roadmap has the potential to improve DSS management by identifying early targets for prevention of the fibrotic lesion, and may also prove beneficial in other fibrotic cardiovascular diseases associated with altered flow.

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“…A decrease in AoSA from 130 • to 110 • was accompanied by up to 23% and 69% increase in TSM and TSG, respectively. Given the wide range of AoSA values reported in the literature (Kleinert and Geva, 1993;Yap et al, 2008;Barboza et al, 2013), more dramatic mechanical stress alterations might be expected in some cases. In contrast, the steepening of the AoSA did not alter the oscillatory characteristics of the WSS, as suggested by the relatively similar OSI values predicted by the N-LV and S-LV models.…”

Section: Aosa Steepening Subjects the Septal Wall To Wss Overloadsmentioning

confidence: 99%

Impact of Aortoseptal Angle Abnormalities and Discrete Subaortic Stenosis on Left-Ventricular Outflow Tract Hemodynamics: Preliminary Computational Assessment

Shar

Brown

Keswani

et al. 2020

Front. Bioeng. Biotechnol.

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Discrete subaortic stenosis (DSS) is an obstruction of the left ventricular outflow tract (LVOT) due to the formation of a fibromuscular membrane upstream of the aortic valve. DSS is a major risk factor for aortic regurgitation (AR), which often persists after surgical resection of the membrane. While the etiology of DSS and secondary AR is largely unknown, the frequent association between DSS and aortoseptal angle (AoSA) abnormalities has supported the emergence of a mechanobiological pathway by which hemodynamic stress alterations on the septal wall could trigger a biological cascade leading to fibrosis and membrane formation. The resulting LVOT flow disturbances could activate the valve endothelium and contribute to AR. In an effort to assess this hypothetical mechano-etiology, this study aimed at isolating computationally the effects of AoSA abnormalities on septal wall shear stress (WSS), and the impact of DSS on LVOT hemodynamics. Two-dimensional computational fluid dynamics models featuring a normal AoSA (N-LV), a steep AoSA (S-LV), and a steep AoSA with a DSS lesion (DSS-LV) were designed to compute the flow in patient-specific left ventricles (LVs). Boundary conditions consisted of transient velocity profiles at the mitral inlet and LVOT outlet, and patient-specific LV wall motion. The deformation of the DSS lesion was computed using a two-way fluid-structure interaction modeling strategy. Turbulence was accounted for via implementation of the k-ω turbulence model. While the N-LV and S-LV models generated similar LVOT flow characteristics, the DSS-LV model resulted in an asymmetric LVOT jet-like structure, subaortic stenotic conditions (up to 2.4-fold increase in peak velocity, 45% reduction in effective jet diameter vs. N-LV/S-LV), increased vorticity (2.8-fold increase) and turbulence (5-and 3-order-ofmagnitude increase in turbulent kinetic energy and Reynolds shear stress, respectively). The steep AoSA subjected the septal wall to a 23% and 69% overload in temporal shear magnitude and gradient, respectively, without any substantial change in oscillatory shear

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Subaortic Membrane and Aorto-Septal Angle

Cited by 12 publications

References 19 publications

Can Fetal Echocardiographic Measurements of the Left Ventricular Outflow Tract Angle Detect Fetuses with Conotruncal Cardiac Anomalies?

Can Fetal Echocardiographic Measurements of the Left Ventricular Outflow Tract Angle Detect Fetuses with Conotruncal Cardiac Anomalies?

Discrete Subaortic Stenosis: Perspective Roadmap to a Complex Disease

Impact of Aortoseptal Angle Abnormalities and Discrete Subaortic Stenosis on Left-Ventricular Outflow Tract Hemodynamics: Preliminary Computational Assessment

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