主动脉瓣上狭窄威廉姆斯综合症

Supravalvar Aortic Stenosis,PF chen2017-11-29,1,Supravalvar is the least common form of left ventricular outflow tract (LVOT) obstruction , accounting for 8 to 14 percent of all cases of aortic stenosisSupravalvar AS is one of the characteristic findings of Williams syndrome along with unusual elfin facies, intellectual disability, and hypercalcemiaWilliams 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,2,Anatomy,3,Anatomy,Hourglass deformity （60-75%）(Discrete)Discrete membranous stenosisDiffuse narrowing （25-40%）,4,Histologic features,Hypertrophied smooth muscle cellsCollagen content Elastic tissue（Williams syndrome ）,5,Other cardiovascular anomalies,The aortic valve leaflets may be thickened, redundant, and have reduced mobilityCoronary artery stenosisOstial stenoses of the carotid, renal, iliac arteriesPulmonary artery stenosesThe mitral valve is usually normal,6,Physiology,7,Physiology,Significant obstruction is associated with a hyperdynamic, hypertrophied left ventricleCoronary artery enlargement and dilatation of the sinuses of Valsalva due to elevated systolic pressure in the aortic root,8,Coronary artery stenosis can occur due to focal or diffuse coronary narrowing, or due to obstruction by redundant, dysplastic aortic valve leaflets,9,Coanda effect,Supravalvar AS creates a systolic jet that tends to hug the aortic wall and transfer kinetic energy into the right innominate arteryThe higher blood pressure in the right than left arm,10,Clinical features,11,Clinical features,Williams syndrome : mental deficiency hypercalcemia renovascular hypertension elfin facies short statureA loud systolic ejection murmur and a thrill at the first right intercostal spaceThe second heart sound may be accentuated due to elevated pressure in the aorta proximal to the stenosisCoanda effect,12,Diagnosis,13,Diagnosis,Echocardiography Assess left ventricle function and hypertrophy and estimate the gradient across the obstructionMRI Provide excellent anatomic detail of supravalvar aortic obstruction, together with associated aortic branch vessel diseaseCardiac catheterization Provide precise hemodynamic and angiographic evaluation, additional lesions are suspected, such as coronary, carotid, renal, or pulmonary artery stenoses.,14,15,Surgical repair,16,Surgical repair,The indications for surgery are uncertain because experience is limitedRecommend operation for symptomatic disease and for patients with a measured gradient at catheterization of more than 30 mmHg,17,Surgical repair,Single patch enlargement into the sinotubular junction just above the aortic rootBifurcated patches extend into two sinusesSeparate three sinus patch enlargement methods,18,Surgical repair,Relief of diffuse obstruction is more complex surgical options include extensive endarterectomy with patch aortoplasty or resection of the stenotic segment with end-to-end anastomosis to the distal ascending aorta, with or without insertion of a pulmonary autograftTranscatheter stent placement smaller aortic branch vessels,19,Outcome,20,Outcome,The operative mortality ranged from 1 to 9 percent.Among patients discharged from the hospital, survival ranged from 94 to 98 percent at 10 y