Pediatric Subvalvar Aortic Stenosis Clinical Presentation
- Author: Douglas J Schneider, MD; Chief Editor: Howard S Weber, MD, FSCAI more...
Symptoms of subvalvar aortic stenosis (SAS ) are rare in infancy and uncommon in early childhood, even if the stenosis is severe.
Isolated SAS may be diagnosed relatively late in life because of the progressive nature of the lesion and because patients lack symptoms that prompt evaluation. The diagnosis is frequently made during an evaluation for an asymptomatic heart murmur.
When present, symptoms include dyspnea on exertion, effort syncope and presyncope, angina, orthopnea, heart failure, and sudden cardiac death. Most of these symptoms occur in children, adolescents, and young adults aged 10-21 years with moderate or severe left ventricular outflow tract (LVOT) obstruction and peak-to-peak pressure gradients of more than 50 mm Hg.
Exertional dyspnea is the most common symptom, occurring in as many as 40% of symptomatic patients. Exertional dyspnea with orthopnea reflects various degrees of pulmonary venous hypertension due to elevated LV filling pressure resulting from impaired diastolic compliance of the hypertrophied LV.
Effort syncope and presyncope occur more frequently in SAS than they do in stenosis of the aortic valve. Syncope during exertion occurs because cerebral perfusion decreases when arterial pressure declines consequent to systemic vasodilation in the presence of a fixed cardiac output. Presyncope may manifest as a graying-out spell or as dizziness on effort because of exertional hypotension.
In pediatric patients, syncope and presyncope at rest are rare. Their presence may indicate a cardiac arrhythmia, notably transient ventricular arrhythmia.
Angina may occur in as many as 25% of symptomatic patients with an LVOT obstruction that is more than mild. Exertion commonly precipitates the condition, and rest relieves it. Angina occurs in the absence of coronary artery disease. It results from the combination of increased oxygen demand by hypertrophied myocardium and reduced oxygen delivery secondary to decreased cardiac output and compression of the coronary vessels.
Symptoms of associated congenital heart defects frequently mask those of subvalvar aortic stenosis (SAS). In most patients, in fact, SAS is detected in the course of follow-up care for associated congenital heart defects or during evaluation of a heart murmur.
The physical growth of the child with SAS is usually normal. Peripheral pulses are symmetrical and rarely of small volume, unless severe left ventricular outflow tract (LVOT) obstruction is present.
A prominent a wave in the jugular venous pulse occasionally occurs in children with SAS. This wave reflects reduced right ventricular compliance consequent to a hypertrophied ventricular septum.
A palpable carotid thrill and a left parasternal thrill are present in one third of patients with mild SAS (pressure gradient < 50 mm Hg) and in approximately one half of patients with more-than-mild SAS. A forceful LV apical impulse is present in most patients with moderate or severe SAS.
The first heart sound is normal. The second heart sound can be narrowly split or single because of prolonged LV systole. Paradoxical splitting of the second heart sound, which suggests associated LV dysfunction, may occur in severe SAS.
A low-pitched ejection systolic murmur of 2-4/6 intensity is best appreciated in second and third left parasternal spaces, with radiation to suprasternal notch. This murmur is typically present in all cases of isolated SAS. The length of the murmur is proportional to the degree of obstruction.
An ejection click opening the ejection murmur is absent in isolated SAS. This is an important clue for differentiating this murmur from that of aortic valve stenosis.
A high-pitched, early diastolic murmur of aortic regurgitation in the same area is present in 30-50% of patients. A pansystolic murmur of mitral regurgitation due to dysfunction of the papillary muscle is sometimes heard.
Iwata Y, Imai Y, Shin'oka T, Kurosawa H. Subaortic stenosis associated with systolic anterior motion. Heart Vessels. 2008 Nov. 23(6):436-9. [Medline].
Somerville J, Stone S, Ross D. Fate of patients with fixed subaortic stenosis after surgical removal. Br Heart J. 1980 Jun. 43(6):629-47. [Medline]. [Full Text].
Bezold LI, Smith EO, Kelly K, et al. Development and validation of an echocardiographic model for predicting progression of discrete subaortic stenosis in children. Am J Cardiol. 1998 Feb 1. 81(3):314-20. [Medline].
Edwards JE. Pathology of left ventricular outflow tract obstruction. Circulation. 1965 Apr. 31:586-99. [Medline].
Pavione MA, Mendonça JT, Souza IS, Russo MA. Accessory mitral leaflet: an uncommon form of subaortic stenosis. Rev Bras Cir Cardiovasc. 2012 Jul-Sep. 27(3):477-80. [Medline].
Ezon DS. Fixed subaortic stenosis: a clinical dilemma for clinicians and patients. Congenit Heart Dis. 2013 Sep. 8(5):450-6. [Medline].
Gokalp S, Oztunc F. Clinically asymptomatic myocardial bridging in a child with familial subaortic stenosis. Cardiol Young. 2013 Jun 28. 1-3. [Medline].
Barkhordarian R, Wen-Hong D, Li W, et al. Geometry of the left ventricular outflow tract in fixed subaortic stenosis and intact ventricular septum: an echocardiographic study in children and adults. J Thorac Cardiovasc Surg. 2007 Jan. 133(1):196-203. [Medline].
Kleinert S, Geva T. Echocardiographic morphometry and geometry of the left ventricular outflow tract in fixed subaortic stenosis. J Am Coll Cardiol. 1993 Nov 1. 22(5):1501-8. [Medline].
Reist-Marti SB, Dolf G, Leeb T, et al. Genetic evidence of subaortic stenosis in the Newfoundland dog. Vet Rec. 2012 Jun 9. 170 (23):597. [Medline].
Newfeld EA, Muster AJ, Paul MH, et al. Discrete subvalvular aortic stenosis in childhood. Study of 51 patients. Am J Cardiol. 1976 Jul. 38(1):53-61. [Medline].
Wright GB, Keane JF, Nadas AS, et al. Fixed subaortic stenosis in the young: medical and surgical course in 83 patients. Am J Cardiol. 1983 Oct 1. 52(7):830-5. [Medline].
Suri RM, Dearani JA, Schaff HV, Danielson GK, Puga FJ. Long-term results of the Konno procedure for complex left ventricular outflow tract obstruction. J Thorac Cardiovasc Surg. 2006 Nov. 132(5):1064-71. [Medline].
Karamlou T, Gurofsky R, Bojcevski A, et al. Prevalence and associated risk factors for intervention in 313 children with subaortic stenosis. Ann Thorac Surg. 2007 Sep. 84(3):900-6; discussion 906. [Medline].
Rohlicek CV, del Pino SF, Hosking M, Miro J, Côté JM, Finley J. Natural history and surgical outcomes for isolated discrete subaortic stenosis in children. Heart. 1999 Dec. 82(6):708-13. [Medline]. [Full Text].
Gersony WM. Natural history of discrete subvalvar aortic stenosis: management implications. J Am Coll Cardiol. 2001 Sep. 38(3):843-5. [Medline].
Brauner R, Laks H, Drinkwater DC Jr, Shvarts O, Eghbali K, Galindo A. Benefits of early surgical repair in fixed subaortic stenosis. J Am Coll Cardiol. 1997 Dec. 30(7):1835-42. [Medline].
de Agustin JA, Gomez de Diego JJ, Marcos-Alberca P, Macaya C, Perez de Isla L. Combined subaortic membrane and aortic valve stenosis: additive value of three-dimensional echocardiography. Eur Heart J Cardiovasc Imaging. 2013 Oct 18. [Medline].
Singh GK, Shiota T, Cobanoglu A, et al. Diagnostic accuracy and role of intraoperative biplane transesophageal echocardiography in pediatric patients with left ventricle outflow tract lesions. J Am Soc Echocardiogr. 1998 Jan. 11(1):47-56. [Medline].
Brown JW, Ruzmetov M, Vijay P, et al. Operative results and outcomes in children with Shone's anomaly. Ann Thorac Surg. 2005 Apr. 79(4):1358-65. [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].
Guglin M, Kristof-Kuteyeva O. Congenital discrete subaortic stenosis in pregnancy: case report and literature review. J Heart Valve Dis. 2013 May. 22(3):439-44. [Medline].