Aortic regurgitation overview
Aortic Regurgitation Microchapters |
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor-in-Chief: Cafer Zorkun, M.D., Ph.D. [2]; Varun Kumar, M.B.B.S.; Lakshmi Gopalakrishnan, M.B.B.S.
Overview
Aortic insufficiency refers to the retrograde or backwards flow of blood from the aorta into the left ventricle during diastole.[1][2][3][4]
Causes
Aortic insufficiency can be an acute illness or a chronic illness and the causes differ depending upon the acuity of the disease. In general, aortic insufficiency is due to abnormalities of the aortic valve itself or the aortic root. Aortic regurgitation secondary to dilation of the ascending aorta has overtaken the valvular aortic disease as the most common cause of aortic regurgitation.
Pathophysiology
In aortic insufficiency (AI), when the pressure in the left ventricle falls below the pressure in the aorta, the aortic valve is not able to completely close. This causes a leaking of blood from the aorta into the left ventricle. This means that some of the blood that was already ejected from the heart is regurgitating back into the heart. The percentage of blood that regurgitates back through the aortic valve due to AI is known as the regurgitant fraction. For instance, if an individual with AI has a stroke volume of 100ml and during ventricular diastole 25ml regurgitates back through the aortic valve, the regurgitant fraction is 25%. This regurgitant flow causes a decrease in the diastolic blood pressure in the aorta, and therefore an increase in the pulse pressure (systolic pressure - diastolic pressure). Thus, physical examination will reveal a bounding pulse, especially in the radial artery.
Diagnosis
Electrocardiogram
There is often evidence of left ventricular hypertrophy and left axis deviation.
Chest X Ray
There may be evidence of cardiomegaly.
Echocardiography
Echocardiography provides two-dimensional views of the regurgitant jet and allows measurement of both the velocity and the volume of the jet. In severe aortic insufficiency, the regurgitant jet width is more than 65% of the width of the left ventricular outflow tract (LVOT) and / or there is flow reversal in the descending aorta.
Aortography
A root shot on the aortogram can be used to gauge the amount of aortic insufficiency.
Cardiac MRI
Cardiac MRI can be used to quantify aortic insufficiency.
Cardiac Catheterization
Although echocardiography is now the primary imaging modality used to evaluate aortic insufficiency, cardiac catheterization is often performed in the patient with aortic insufficiency primarily to assess for the presence of epicardial coronary artery disease prior to surgical aortic valve replacement. Aortography can also be performed to assess the severity of aortic insufficiency. The presence or absence of an aortic dissection can be evaluated. Left ventricular function (hemodynamics), size and systolic function (ejection fraction) can also be evaluated.
Treatment
Aortic insufficiency can be treated either medically with vasodilators or surgically with aortic valve replacement, depending on the acuteness of presentation, the symptoms and signs associated with the disease process, and the degree of left ventricular dysfunction.
In general, acute aortic insufficiency with left ventricular dysfunction, symptomatic severe aortic insufficiency, asymptomatic aortic insufficiency with left ventricular dilatation or ejection fraction < 50% should be treated surgically with aortic valve replacement if there are no contraindications.
Chronic aortic insufficiency is managed with vasodilators [5] such as ACE inhibitors , hydralazine or nifidipine to reduce the afterload. Indications for surgery in chronic aortic insufficiency include heart failure with a reduced ejection fraction and increased left ventricular dimensions.
References
- ↑ Connolly HM, Crary JL, McGoon MD; et al. (1997). "Valvular heart disease associated with fenfluramine-phentermine". N. Engl. J. Med. 337 (9): 581–8. doi:10.1056/NEJM199708283370901. PMID 9271479.
- ↑ Weissman NJ (2001). "Appetite suppressants and valvular heart disease". Am. J. Med. Sci. 321 (4): 285–91. doi:10.1097/00000441-200104000-00008. PMID 11307869.
- ↑ Schade R, Andersohn F, Suissa S, Haverkamp W, Garbe E (2007). "Dopamine agonists and the risk of cardiac-valve regurgitation". N. Engl. J. Med. 356 (1): 29–38. doi:10.1056/NEJMoa062222. PMID 17202453.
- ↑ Zanettini R, Antonini A, Gatto G, Gentile R, Tesei S, Pezzoli G (2007). "Valvular heart disease and the use of dopamine agonists for Parkinson's disease". N. Engl. J. Med. 356 (1): 39–46. doi:10.1056/NEJMoa054830. PMID 17202454.
- ↑ Evangelista A, Tornos P, Sambola A, Permanyer-Miralda G, Soler-Soler J (2005). "Long-term vasodilator therapy in patients with severe aortic regurgitation". The New England Journal of Medicine. 353 (13): 1342–9. doi:10.1056/NEJMoa050666. PMID 16192479. Retrieved 2011-03-29. Unknown parameter
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