Pediatric Supravalvar Aortic Stenosis Workup
- Author: Anita Krishnan, MD; Chief Editor: Howard S Weber, MD, FSCAI more...
SVAS produces abnormalities that are evident on electrocardiography (ECG) and chest radiography. These include increased left ventricular voltages from left ventricular hypertrophy. ST and T wave changes may be present if there is coronary involvement. Additionally, if right ventricular outflow tract obstruction is present, there may be voltage criteria for right ventricular hypertrophy.
The principal diagnostic test, however, is two-dimensional echocardiography. Cardiac catheterization along with angiography may be performed at an increased risk as indicated, but it may be necessary to evaluate the severity of the lesion and to confirm the coexisting anomalies prior to surgery if they cannot be accurately assessed with other modalities. Magnetic resonance imaging (MRI) may be utilized to evaluate for stenosis of the arch vessels or for better delineation of the anatomy if cardiac catheterization is not performed.
Go to Imaging in Aortic Stenosis for more complete information on this topic.
The anatomic diagnosis of SVAS can reliably be made from two-dimensional echocardiography that uses multiple views, including parasternal, apical long-axis, and suprasternal (seen in the image below).
In SVAS with hourglass deformity and diffuse hypoplasia, the diameter of the ascending aorta is smaller than that of the aortic root. In SVAS with fibrous diaphragm, the external ascending aortic diameter is normal, although an echogenic membrane is commonly observed above the sinuses of Valsalva.
Turbulent color flow mapping indicates the site of hemodynamically significant obstruction in relation to the origin of the coronary ostia. The incidence of coronary artery involvement is high in SVAS.
Doppler peak gradient overestimates and, therefore, does not predict catheter-measured gradient well in patients with SVAS and may not be reliable in assessing its severity and guiding the need for intervention.
A retrograde aortic catheterization with an end-hole catheter can be used to localize the site of obstruction by showing the pressure gradient above the aortic valve on pullback tracing. Cutting balloon angioplasty and endovascular stenting have been utilized with variable success for associated peripheral pulmonary artery stenosis when conventional balloon angioplasty fails.
Complications include blood vessel rupture, tachyarrhythmias, bradyarrhythmias, and vascular occlusion. Postcatheterization precautions are for hemorrhage, vascular disruption after balloon dilation, pain, nausea and vomiting, and arterial or venous obstruction from thrombosis or spasm.
Cardiac asystole and mortality due to coronary events have been reported during catheterization and during the postprocedure period. Cardiac catheterization should therefore be performed only if clearly indicated. General anesthesia should be undertaken with close supervision and by an experienced anesthesiologist. Any form of anesthesia should avoid hypotension or a decrease in systemic vascular resistance which may precipitate coronary artery ischemia.
Chest radiography is of low sensitivity, although the cardiac silhouette may be variably increased and the ascending aorta may be asymmetrically dilated. The presence of both findings indicates hemodynamically significant SVAS.
ECG usually reveals left ventricular hypertrophy, depending on the severity of stenosis. ST/T segment changes may be present with involvement of coronary ostia and the coronary arteries. Right ventricular hypertrophy may be present if there is associated right ventricular outflow tract obstruction.
A biplane left ventriculogram and an aortogram can reveal the morphology of supravalvar narrowing, stenosis of the arch vessels, aortic root abnormalities, and location of the coronary artery ostia in relation to the site of supravalve obstruction (see the image below). The coronary arteries may or may not appear abnormal. Right ventricular or pulmonary arterial angiography should be performed simultaneously in order to discern the presence of peripheral pulmonary artery stenosis, particularly in Williams syndrome.
Magnetic Resonance Imaging
Although magnetic resonance imaging (MRI) can provide high definition of SVAS, obtaining an MRI in infants and young children may require sedation, which carries a risk of sudden death. Therefore, this study should be undertaken with close supervision and administered by an experienced anesthesiologist. MRI may be particularly useful in delineating aortic arch anatomy and evaluating for stenosis of the arch vessels.
Multislice computed tomography (CT) scanning with angiography can generate high-resolution images of aortic valve lesions within seconds. However, this test exposes the pediatric patient to radiation, although it can now be performed without sedation (ultrafast flash CT).
Myocardial hypertrophy, coronary intimal hyperplasia, and atherosclerotic changes can be observed in most cases of SVAS. Subendocardial fibrosis may be present in severe cases of SVAS. Abnormal deposition of elastin in arterial walls of patients with SVAS has been seen, which leads to the increased proliferation of arterial smooth muscle cells, resulting in the formation of hyperplastic intimal lesions.
Obtain a genetic evaluation for patients with SVAS to confirm the diagnosis of Williams syndrome, which is often associated with SVAS. Molecular diagnosis of Williams syndrome can be made by fluorescent in situ hybridization (FISH) using Williams probe.
Micale L, Turturo MG, Fusco C, et al. Identification and characterization of seven novel mutations of elastin gene in a cohort of patients affected by supravalvular aortic stenosis. Eur J Hum Genet. 2009 Oct 21. [Medline].
Peterson TA, Todd DB, Edwards JE. Supravalvular aortic stenosis. J Thorac Cardiovasc Surg. 1965 Nov. 50(5):734-41. [Medline].
Edwards JE. Pathology of left ventricular outflow tract obstruction. Circulation. 1965. 31:586-99.
Thistlethwaite PA, Madani MM, Kriett JM, Milhoan K, Jamieson SW. Surgical management of congenital obstruction of the left main coronary artery with supravalvular aortic stenosis. J Thorac Cardiovasc Surg. 2000 Dec. 120(6):1040-6. [Medline].
French JW, Guntheroth WG. An explanation of asymmetric upper extremity blood pressures in supravalvular aortic stenosis: the Coanda effect. Circulation. 1970 Jul. 42(1):31-6. [Medline].
Gersony WM, Hayes CJ, Driscoll DJ, et al. Bacterial endocarditis in patients with aortic stenosis, pulmonary stenosis, or ventricular septal defect. Circulation. 1993 Feb. 87(2 Suppl):I121-6. [Medline].
Wilson W, Taubert KA, Gewitz M, et al. Prevention of infective endocarditis: guidelines from the American Heart Association: a guideline from the American Heart Association Rheumatic Fever, Endocarditis and Kawasaki Disease Committee, Council on Cardiovascular Disease in the Young, and the Council on Clinical Cardiology, Council on Cardiovascular Surgery and Anesthesia, and the Quality of Care and Outcomes Research Interdisciplinary Working Group. J Am Dent Assoc. 2007 Jun. 138(6):739-45, 747-60. [Medline]. [Full Text].
Ewart AK, Morris CA, Atkinson D, et al. Hemizygosity at the elastin locus in a developmental disorder, Williams syndrome. Nat Genet. 1993 Sep. 5(1):11-6. [Medline].
Brown JW, Ruzmetov M, Vijay P, et al. Surgical repair of congenital supravalvular aortic stenosis in children. Eur J Cardiothorac Surg. 2002 Jan. 21(1):50-6. [Medline].
Wren C, Oslizlok P, Bull C. Natural history of supravalvular aortic stenosis and pulmonary artery stenosis. J Am Coll Cardiol. 1990 Jun. 15(7):1625-30. [Medline].
Wessel TR, Arant CB, Olson MB, et al. Relationship of physical fitness vs body mass index with coronary artery disease and cardiovascular events in women. JAMA. 2004 Sep 8. 292(10):1179-87. [Medline].
Bird LM, Billman GF, Lacro RV, et al. Sudden death in Williams syndrome: report of ten cases. J Pediatr. 1996 Dec. 129(6):926-31. [Medline].
Pieles GE, Ofoe V, Morgan GJ. Severe Left Main Coronary Artery Stenosis with Abnormal Branching Pattern in a Patient with Mild Supravalvar Aortic Stenosis and Williams-Beuren Syndrome. Congenit Heart Dis. 2013 May 22. [Medline].
Martin R, Lairez O, Boudou N, Méjean S, Lhermusier T, Dumonteil N, et al. Relation between left ventricular outflow tract obstruction and left ventricular shape in patients with hypertrophic cardiomyopathy: A cardiac magnetic resonance imaging study. Arch Cardiovasc Dis. 2013 Aug-Sep. 106(8-9):440-7. [Medline].
Jureidini SB, Marino CJ, Singh GK, et al. Main coronary artery and coronary ostial stenosis in children: detection by transthoracic color flow and pulsed Doppler echocardiography. J Am Soc Echocardiogr. 2000 Apr. 13(4):255-63. [Medline].
Tani LY, Minich LL, Pagotto LT, Shaddy RE. Usefulness of doppler echocardiography to determine the timing of surgery for supravalvar aortic stenosis. Am J Cardiol. 2000 Jul 1. 86(1):114-6. [Medline].
Sugiyama H, Veldtman GR, Norgard G, Lee KJ, Chaturvedi R, Benson LN. Bladed balloon angioplasty for peripheral pulmonary artery stenosis. Catheter Cardiovasc Interv. 2004 May. 62(1):71-7. [Medline].
Dridi SM, Foucault Bertaud A, Igondjo Tchen S, et al. Vascular wall remodeling in patients with supravalvular aortic stenosis and Williams Beuren syndrome. J Vasc Res. 2005 May-Jun. 42(3):190-201. [Medline].
[Guideline] Bonow RO, Carabello BA, Kanu C, et al. ACC/AHA 2006 guidelines for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (writing committee to revise the 1998 Guidelines for the Management of Patients With Valvular Heart Disease): developed in collaboration with the Society of Cardiovascular Anesthesiologists: endorsed by the Society for Cardiovascular Angiography and Interventions and the Society of Thoracic Surgeons. Circulation. 2006 Aug 1. 114(5):e84-231. [Medline].
Kavarana MN, Riley M, Sood V, Ohye RG, Devaney EJ, Bove EL, et al. Extended single-patch repair of supravalvar aortic stenosis: a simple and effective technique. Ann Thorac Surg. 2012 Apr. 93(4):1274-8; discussion 1278-9. [Medline].
Ayoub C, Ranasinghe I, Yiannikas J. Successful negative inotropic treatment of acute left ventricular outflow tract obstruction by elongated mitral valve leaflet. J Clin Ultrasound. 2013 Sep 20. [Medline].
McElhinney DB, Petrossian E, Tworetzky W, Silverman NH, Hanley FL. Issues and outcomes in the management of supravalvar aortic stenosis. Ann Thorac Surg. 2000 Feb. 69(2):562-7. [Medline].