主动脉瓣上狭窄威廉姆斯综合症PPT课件

Supravalvar Aortic Stenosis
PF chen 2017-11-29 1
• Supravalvar is the least common form of left ventricular outflow tract (LVOT) obstruction , accounting for 8 to 14 percent of all cases of aortic stenosis • Supravalvar AS is one of the characteristic findings of Williams syndrome along with unusual elfin facies, intellectual disability, and hypercalcemia • Williams syndrome is caused by a deletion of the elastin gene on chromosome 7q11.23. • Other forms of supravalvar AS are also associated with mutations of the elastin gene
• Elastic tissue↓（Williams syndrome ）
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Other cardiovascular anomalies
• The aortic valve leaflets may be thickened, redundant, and have reduced mobility • Coronary artery stenosis • Ostial stenoses of the carotid, renal, iliac arteries • Pulmonary artery stenoses • The mitral valve is usually normal
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Coanda effect
• Supravalvar AS creates a systolic jet that tends to hug the aortic wall and transfer kinetic energy into the right innominate artery • The higher blood pressure in the right than left arm
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Anatomy
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Anatomy
• Hourglass deformity （60-75%）(Discrete) • Discrete membranous stenosis • Diffuse narrowing （25-40%）
4Histologic 源自eatures• Hypertrophied smooth muscle cells↑ • Collagen content ↑
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Physiology
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Physiology
• Significant obstruction is associated with a hyperdynamic, hypertrophied left ventricle • Coronary artery enlargement and dilatation of the sinuses of Valsalva due to elevated systolic pressure in the aortic root
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• Coronary artery stenosis can occur due to focal or diffuse coronary narrowing, or due to obstruction by redundant, dysplastic aortic valve leaflets
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Diagnosis
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Diagnosis
• Echocardiography
Assess left ventricle function and hypertrophy and estimate the gradient across the obstruction
• MRI
Provide excellent anatomic detail of supravalvar aortic obstruction, together with associated aortic branch vessel disease
• Cardiac catheterization
Provide precise hemodynamic and angiographic evaluation, additional lesions are suspected, such as coronary, carotid, renal, or pulmonary artery stenoses.
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Clinical features
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Clinical features
• Williams syndrome :
mental deficiency
hypercalcemia renovascular hypertension elfin facies short stature
• A loud systolic ejection murmur and a thrill at the first right intercostal space • The second heart sound may be accentuated due to elevated pressure in the aorta proximal to the stenosis • Coanda effect
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Surgical repair
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Surgical repair
• The indications for surgery are uncertain because experience is limited • Recommend operation for symptomatic disease and for patients with a measured gradient at catheterization of more than 30 mmHg