Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Synonyms and keywords: LV outflow tract obstruction; LVOT obstruction
Overview
Left ventricular outflow tract obstruction refers to any functional or anatomic obstruction of flow out of the left ventricle.
Causes
2008 ACC/AHA Guidelines for the Management of Adults With Congenital Heart Disease (DO NOT EDIT)[1]
Recommendations for Evaluation of the Unoperated Patient (DO NOT EDIT)[1]
| Class I
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| 1. Primary imaging and hemodynamic assessment of AS and aortic valve disease are recommended by echocardiography- Doppler to evaluate the presence and severity of AS or AR; LV size, function, and mass; and dimensions and anatomy of the ascending aorta and associated lesions. (Level of Evidence: B)
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| 2. Echocardiography is recommended for reevaluation of patients with AS who experience a change in signs or symptoms and for assessment of changes in AS hemodynamics during pregnancy. (Level of Evidence: B)
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| 3. In asymptomatic adolescents and young adults, echocardiography- Doppler is recommended yearly for AS with a mean Doppler gradient greater than 30 mm Hg or peak instantaneous gradient greater than 50 mm Hg and every 2 years for patients with lesser gradients.(Level of Evidence: C)
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| 4. Cardiac catheterization is recommended when noninvasive measurements are inconclusive or discordant with clinical signs. (Level of Evidence:C)
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| 5. Coronary angiography is recommended before aortic valve surgery for coronary angiography in adults at risk for coronary artery disease. (Level of Evidence:B)
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| 6. Coronary angiography is recommended before a Ross procedure if noninvasive imaging of the coronary arteries is inadequate. (Level of Evidence:C)
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| 7. A yearly ECG is recommended in young adults less than 30 years of age with mean Doppler gradients greater than 30 mm Hg or peak Doppler gradients greater than 50 mm Hg. (Level of Evidence:C)
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| 8. An ECG is recommended every other year in young adults less than 30 years of age with mean Doppler gradients less than 30 mm Hg or peak Doppler gradients less than 50 mm Hg. (Level of Evidence:C)
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| Class III
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| 1. Exercise stress testing should not be performed in symptomatic patients with AS or those with repolarization abnormality on ECG or systolic dysfunction on echocardiography.(Level of Evidence: B)
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| Class IIb
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| 1. In asymptomatic young adults less than 30 years of age, exercise stress testing is reasonable to determine exercise capability, symptoms, and blood pressure response. (Level of Evidence:C)
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| 2. Exercise stress testing is reasonable for patients with a mean Doppler gradient greater than 30 mm Hg or peak Doppler gradient greater than 50 mm Hg if the patient is interested in athletic participation or if clinical findings differ from noninvasive measurements. (Level of Evidence:C)
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| 3. Exercise stress testing is reasonable for the evaluation of an asymptomatic young adult with a mean Doppler gradient greater than 40 mm Hg or a peak Doppler gradient greater than 64 mm Hg or when the patient anticipates athletic participation or pregnancy. (Level of Evidence:C)
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| 4. Dobutamine stress testing can be beneficial in the evaluation of a mild aortic valve gradient in the face of low LV ejection fraction and reduced cardiac output. (Level of Evidence:B)
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| 5. MRI/CT can be beneficial to add important information about the anatomy of the thoracic aorta. (Level of Evidence:C)
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| 6. Exercise stress testing can be useful to evaluate blood pressure response or elicit exercise-induced symptoms in asymptomatic older adults with AS. (Level of Evidence:B)
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| Class IIb
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| 1. Magnetic resonance angiography may be beneficial in quantifying AR when other data are ambiguous or borderline. (Level of Evidence:C)
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ACC/ AHA Guidelines - Recommendation for Medical Therapy for Left Ventricular Outflow Tract Obstruction and Associated Lesions (DO NOT EDIT)
| Class III
|
| 1. Vasodilator therapy is not indicated for long-term therapy in AR for the following:
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| a. The asymptomatic patient with only mild to moderate AR and normal LV function. (Level of Evidence: B)
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| b. The asymptomatic patient with LV systolic dysfunction who is otherwise a candidate for aortic valve replacement (AVR). (Level of Evidence: B)
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| c. The asymptomatic patient with either LV systolic function or mild to moderate LV diastolic dysfunction who is otherwise a candidate for AVR. (Level of Evidence: C)
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| Class IIa
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| 1. It is reasonable to treat systemic hypertension in patients with AS while monitoring diastolic blood pressure to avoid reducing coronary perfusion. (Level of Evidence:A)
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| 2. It is reasonable to administer beta blockers in patients with BAV and aortic root dilatation. (Level of Evidence:B)
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| 3. It is reasonable to use long-term vasodilator therapy in patients with AR and systemic hypertension while carefully monitoring diastolic blood pressure to avoid reducing coronary perfusion. (Level of Evidence:B)
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| Class IIb
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| 1. It may be reasonable to treat patients with BAV and risk factors for atherosclerosis with statins with the aim of ‘‘slowing down degenerative changes in the aortic valve and preventing atherosclerosis. (Level of Evidence:A)
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ACC/ AHA Guidelines - Recommendations for Catheter Interventions for Adults With Valvular Aortic Stenosis (DO NOT EDIT)
| Class I
|
| 1. In young adults and others without significantly calcified aortic valves and no AR, aortic balloon valvotomy
is indicated in the following patients. (Level of Evidence: A)
|
| a. Those with symptoms of angina, syncope, dyspnea on exertion, and peak-to-peak gradients at catheterization greater than 50 mm Hg. (Level of Evidence: A)
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| b. Asymptomatic adolescents or young adults who demonstrate ST or T-wave abnormalities in the left precordial leads on ECG at rest or with exercise and a peak-to-peak catheter gradient greater than 60 mm Hg. (Level of Evidence: A)
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| Class III (No Benefit)
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| 1. In older adults, aortic balloon valvotomy is not recommended as an alternative to AVR, although certain younger patients may be an exception and should be referred to a center with experience in aortic balloon valvuloplasties (Level of Evidence: B)
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| 2. In asymptomatic adolescents and young adults, aortic balloon valvotomy should not be performed with a peak-to-peak gradient less than 40 mm Hg without symptoms or ECG changes. (Level of Evidence: B)
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| Class IIa
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| 1. Aortic balloon valvotomy is reasonable in the asymptomatic adolescent or young adult with AS and a peak-to-peak gradient on catheterization greater than 50 mm Hg when the patient is interested in playing competitive sports or becoming pregnant. (Level of Evidence:C)
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| Class IIb
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| 1. Aortic balloon valvotomy may be considered as a bridge to surgery in hemodynamically unstable adults with AS, adults at high risk for AVR, or when AVR cannot be performed secondary to significant co-morbidities. (Level of Evidence:C)
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References
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