Aortic regurgitation overview: Difference between revisions
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==Overview== | ==Overview== | ||
Aortic insufficiency refers to the retrograde or backward flow of [[blood]] from the [[aorta]] into the [[left ventricle]] during [[diastole]].<ref name="pmid9271479">{{cite journal |author=Connolly HM, Crary JL, McGoon MD, ''et al'' |title=Valvular heart disease associated with fenfluramine-phentermine |journal=N. Engl. J. Med. |volume=337 |issue=9 |pages=581–8 |year=1997 |pmid=9271479 |doi=10.1056/NEJM199708283370901|url=http://content.nejm.org/cgi/content/full/337/9/581}}</ref><ref name="pmid11307869">{{cite journal |author=Weissman NJ |title=Appetite suppressants and valvular heart disease |journal=Am. J. Med. Sci. |volume=321 |issue=4 |pages=285–91 |year=2001 |pmid=11307869|doi=10.1097/00000441-200104000-00008}}</ref><ref name="pmid17202453">{{cite journal |author=Schade R, Andersohn F, Suissa S, Haverkamp W, Garbe E |title=Dopamine agonists and the risk of cardiac-valve regurgitation |journal=N. Engl. J. Med. |volume=356 |issue=1 |pages=29–38 |year=2007 |pmid=17202453 |doi=10.1056/NEJMoa062222}}</ref><ref name="pmid17202454">{{cite journal |author=Zanettini R, Antonini A, Gatto G, Gentile R, Tesei S, Pezzoli G |title=Valvular heart disease and the use of dopamine agonists for Parkinson's disease |journal=N. Engl. J. Med. |volume=356 |issue=1 |pages=39–46 |year=2007 |pmid=17202454 |doi=10.1056/NEJMoa054830}}</ref> | Aortic insufficiency refers to the retrograde or backward flow of [[blood]] from the [[aorta]] into the [[left ventricle]] during [[diastole]].<ref name="pmid9271479">{{cite journal |author=Connolly HM, Crary JL, McGoon MD, ''et al'' |title=Valvular heart disease associated with fenfluramine-phentermine |journal=N. Engl. J. Med. |volume=337 |issue=9 |pages=581–8 |year=1997 |pmid=9271479 |doi=10.1056/NEJM199708283370901|url=http://content.nejm.org/cgi/content/full/337/9/581}}</ref><ref name="pmid11307869">{{cite journal |author=Weissman NJ |title=Appetite suppressants and valvular heart disease |journal=Am. J. Med. Sci. |volume=321 |issue=4 |pages=285–91 |year=2001 |pmid=11307869|doi=10.1097/00000441-200104000-00008}}</ref><ref name="pmid17202453">{{cite journal |author=Schade R, Andersohn F, Suissa S, Haverkamp W, Garbe E |title=Dopamine agonists and the risk of cardiac-valve regurgitation |journal=N. Engl. J. Med. |volume=356 |issue=1 |pages=29–38 |year=2007 |pmid=17202453 |doi=10.1056/NEJMoa062222}}</ref><ref name="pmid17202454">{{cite journal |author=Zanettini R, Antonini A, Gatto G, Gentile R, Tesei S, Pezzoli G |title=Valvular heart disease and the use of dopamine agonists for Parkinson's disease |journal=N. Engl. J. Med. |volume=356 |issue=1 |pages=39–46 |year=2007 |pmid=17202454 |doi=10.1056/NEJMoa054830}}</ref> | ||
==Pathophysiology== | ==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]]. | 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]]. | ||
==Causes== | ==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. | 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. | ||
==Epidemiology and Demographics== | |||
The prevalence of aortic regurgitation varies with age, geographic location, and gender.<ref name="pmid10190406">{{cite journal |author=Singh JP, Evans JC, Levy D, Larson MG, Freed LA, Fuller DL, Lehman B, Benjamin EJ |title=Prevalence and clinical determinants of mitral, tricuspid, and aortic regurgitation (the Framingham Heart Study) |journal=[[The American Journal of Cardiology]] |volume=83 |issue=6 |pages=897–902 |year=1999 |month=March |pmid=10190406 |doi= |url=http://linkinghub.elsevier.com/retrieve/pii/S0002-9149(98)01064-9 |accessdate=2011-12-27}}</ref> Aortic insufficiency is unusual before the age of 50 and then increases progressively later in life. Worldwide the most common cause of aortic insufficiency is the [[rheumatic heart disease]], particularly in the Asia, the Middle East, and the North Africa. In the United States, [[senile]] degenerative [[calcific aortic valve disease]] and [[bicuspid aortic valve]] disease are the most common causes. | |||
==Risk Factors== | |||
In the past, the most common risk factor for aortic valvular disease had been the [[rheumatic fever]], with subsequent [[fibrosis]] of the scarred valve then leading to retraction of the [[aortic valve cusps]] and prevention of their apposition during [[diastole]]. In the modern era, a more common risk factor for acquired aortic regurgitation is [[degenerative]] disease of the [[aorta]] and [[aortic valve]] in which case there is [[calcification]] and [[fibrosis]] of the cusps. [[Infective endocarditis]] remains an important risk factor and cause of aortic insufficiency. [[Congenital]] conditions such as congenital [[bicuspid aortic valve]] or a [[ventricular septal defect]] can also result in aortic insufficiency. Patients with [[bicuspid aortic valve]] are at increased risk of developing [[aortic dissection]].<ref name="pmid12186790">{{cite journal |author=Fedak PW, Verma S, David TE, Leask RL, Weisel RD, Butany J |title=Clinical and pathophysiological implications of a bicuspid aortic valve |journal=[[Circulation]] |volume=106 |issue=8 |pages=900–4 |year=2002 |month=August |pmid=12186790 |doi= |url=http://circ.ahajournals.org/cgi/pmidlookup?view=long&pmid=12186790 |accessdate=2011-03-28}}</ref> | |||
==Natural History, Complications and Prognosis== | |||
In acute aortic insufficiency symptoms of [[heart failure]] often develop acutely. Chronic aortic insufficiency is usually insidious and progressive and the patient may remain asymptomatic for years. Once left ventricular dilation and left ventricular failure occur, [[dyspnea on exertion]] and [[exercise intolerance]] begin to occur. Later symptoms such as [[angina]], [[syncope]], and other symptoms of [[heart failure]] are present. | |||
==Diagnosis== | ==Diagnosis== | ||
===History and Symptoms=== | |||
Aortic insufficiency can cause many symptoms such as [[dyspnea]], [[weakness]], and symptoms of [[congestive heart failure]]. Chronic aortic insufficiency maybe without symptoms for several years until decrease in the [[stroke volume]] and [[cardiac output]] due to [[heart failure]] progression. | |||
===Physical Examination=== | |||
A patient with suspected aortic insufficiency may have an early [[diastolic heart murmur]] which is usually a high-pitched sound best heard at the left sternal border. An [[Systolic murmur|ejection systolic 'flow' murmur]] may also be present. The [[apex beat]] is typically displaced down and to the left. A patient with chronic aortic insufficiency may present with signs of [[congestive heart failure]]. | |||
===Cardiac Stress Test=== | |||
A [[exercise stress test|cardiac stress test (CST)]] is an evaluation modality used in cardiology in which the ability of the [[heart]] to respond to stress, either actually induced by exercise or stimulated by pharmacologic agents, is measured in a controlled clinical setting. CST for chronic aortic insufficiency is reasonable for assessment of functional capacity and symptomatic response in patients with a history of equivocal symptoms. | |||
===Electrocardiogram=== | ===Electrocardiogram=== | ||
Electrocardiographic abnormalities in the patient with aortic insufficiency include [[left ventricular hypertrophy]] and [[left axis deviation]]. | |||
===Chest X Ray=== | ===Chest X Ray=== | ||
[[Chest x ray]] findings associated with aortic insufficiency may include [[left ventricular enlargement]], [[cardiomegaly]], prominent [[aortic root]] with valvular [[calcification]], [[prosthetic valve]] dis-lodgement, or aortic dilation. If aortic insufficiency is severe, signs of [[pulmonary edema]] may also be present. | |||
===Echocardiography=== | ===Echocardiography=== | ||
The [[echocardiogram]] is the single most useful diagnostic imaging study in the diagnosis and ongoing surveillance of the severity of aortic insufficiency. Echocardiography allows for serial assessment of left ventricular volumes which can be critical in determining the timing of [[aortic valve replacement]]. Aortic valve replacement should be performed if the [[LVEF]] is ≤ 55% or if [[left ventricular]] end-systolic dimension is > 55mm. | |||
===Aortography=== | ===Aortography=== | ||
A root shot on the aortogram can be used to gauge the amount of aortic insufficiency. | A root shot on the aortogram can be used to gauge the amount of aortic insufficiency. | ||
Revision as of 21:10, 1 February 2013
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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 backward flow of blood from the aorta into the left ventricle during diastole.[1][2][3][4]
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.
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.
Epidemiology and Demographics
The prevalence of aortic regurgitation varies with age, geographic location, and gender.[5] Aortic insufficiency is unusual before the age of 50 and then increases progressively later in life. Worldwide the most common cause of aortic insufficiency is the rheumatic heart disease, particularly in the Asia, the Middle East, and the North Africa. In the United States, senile degenerative calcific aortic valve disease and bicuspid aortic valve disease are the most common causes.
Risk Factors
In the past, the most common risk factor for aortic valvular disease had been the rheumatic fever, with subsequent fibrosis of the scarred valve then leading to retraction of the aortic valve cusps and prevention of their apposition during diastole. In the modern era, a more common risk factor for acquired aortic regurgitation is degenerative disease of the aorta and aortic valve in which case there is calcification and fibrosis of the cusps. Infective endocarditis remains an important risk factor and cause of aortic insufficiency. Congenital conditions such as congenital bicuspid aortic valve or a ventricular septal defect can also result in aortic insufficiency. Patients with bicuspid aortic valve are at increased risk of developing aortic dissection.[6]
Natural History, Complications and Prognosis
In acute aortic insufficiency symptoms of heart failure often develop acutely. Chronic aortic insufficiency is usually insidious and progressive and the patient may remain asymptomatic for years. Once left ventricular dilation and left ventricular failure occur, dyspnea on exertion and exercise intolerance begin to occur. Later symptoms such as angina, syncope, and other symptoms of heart failure are present.
Diagnosis
History and Symptoms
Aortic insufficiency can cause many symptoms such as dyspnea, weakness, and symptoms of congestive heart failure. Chronic aortic insufficiency maybe without symptoms for several years until decrease in the stroke volume and cardiac output due to heart failure progression.
Physical Examination
A patient with suspected aortic insufficiency may have an early diastolic heart murmur which is usually a high-pitched sound best heard at the left sternal border. An ejection systolic 'flow' murmur may also be present. The apex beat is typically displaced down and to the left. A patient with chronic aortic insufficiency may present with signs of congestive heart failure.
Cardiac Stress Test
A cardiac stress test (CST) is an evaluation modality used in cardiology in which the ability of the heart to respond to stress, either actually induced by exercise or stimulated by pharmacologic agents, is measured in a controlled clinical setting. CST for chronic aortic insufficiency is reasonable for assessment of functional capacity and symptomatic response in patients with a history of equivocal symptoms.
Electrocardiogram
Electrocardiographic abnormalities in the patient with aortic insufficiency include left ventricular hypertrophy and left axis deviation.
Chest X Ray
Chest x ray findings associated with aortic insufficiency may include left ventricular enlargement, cardiomegaly, prominent aortic root with valvular calcification, prosthetic valve dis-lodgement, or aortic dilation. If aortic insufficiency is severe, signs of pulmonary edema may also be present.
Echocardiography
The echocardiogram is the single most useful diagnostic imaging study in the diagnosis and ongoing surveillance of the severity of aortic insufficiency. Echocardiography allows for serial assessment of left ventricular volumes which can be critical in determining the timing of aortic valve replacement. Aortic valve replacement should be performed if the LVEF is ≤ 55% or if left ventricular end-systolic dimension is > 55mm.
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 [7] 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.
- ↑ Singh JP, Evans JC, Levy D, Larson MG, Freed LA, Fuller DL, Lehman B, Benjamin EJ (1999). "Prevalence and clinical determinants of mitral, tricuspid, and aortic regurgitation (the Framingham Heart Study)". The American Journal of Cardiology. 83 (6): 897–902. PMID 10190406. Retrieved 2011-12-27. Unknown parameter
|month=ignored (help) - ↑ Fedak PW, Verma S, David TE, Leask RL, Weisel RD, Butany J (2002). "Clinical and pathophysiological implications of a bicuspid aortic valve". Circulation. 106 (8): 900–4. PMID 12186790. Retrieved 2011-03-28. Unknown parameter
|month=ignored (help) - ↑ 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
|month=ignored (help)