Aortic regurgitation general approach to aortic insufficiency: Difference between revisions
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==Overview== | ==Overview== | ||
Aortic insufficiency is defined as | Aortic insufficiency is a valvular disease defined as the inability of the aortic valve to close tightly leading to a backward flow of blood from the aorta into the left ventricle during diastole. | ||
==Classification== | ==Classification== | ||
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==Pathophysiology== | ==Pathophysiology== | ||
During acute aortic regurgitation, there is a sudden large regurgitant volume of blood imposed on the unprepared left ventricle. Because of the acute nature of the onset of the regurgitation, there will be no ventricular dilatation. As the blood flow through the [[aorta]] is reversed, the effective left ventricle stroke volume is reduced. As a result, the left ventricular end diastolic pressures will increase and consequently [[pulmonary edema]] may occur. | |||
==Causes== | ==Causes== | ||
Aortic insufficiency can be caused by defects in the intrinsic valve or ascending aorta (root). | Aortic insufficiency can be caused by defects in the intrinsic valve or the ascending aorta (root). | ||
* '''Intrinsic | * '''Defects in the Intrinsic Valve''': | ||
** Degenerative / calcific aortic valve | ** Degenerative / calcific aortic valve | ||
** [[Endocarditis]] | ** [[Endocarditis]] | ||
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** Anorectic drugs | ** Anorectic drugs | ||
* '''Ascending | * '''Defecst in the Ascending Aorta (Root)''': | ||
** Degenerative | ** Degenerative | ||
** Type A aortic dissection | ** Type A aortic dissection | ||
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==Natural History== | ==Natural History== | ||
There are two main parameters that reflect the overall outcome in patients with aortic insufficiency: | |||
* [[Ejection fraction]] | * [[Ejection fraction]] | ||
* End systolic diameter | * End systolic diameter | ||
[[Left ventricular dysfunction]] develops in patients with aortic insufficiency after decades of the onset of the symptoms. This lag period is longer than that of [[mitral regurgitation]]. | |||
The lower the ejection fraction is, the poorer the outcome is. | |||
==Diagnosis== | ==Diagnosis== | ||
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* [[Palpitations]] | * [[Palpitations]] | ||
Patients having bicuspid aortic valve should be evaluated for [[coarctation of aorta]] if [[hypertension]] is present and for [[dissection of aorta]] if [[chest pain]] is present. Therefore the entire aorta should be scanned either by an [[magnetic resonance angiogram]] ([[MRA]]) or [[computed tomography]] ([[CT]]). | |||
===Physical Examination=== | ===Physical Examination=== | ||
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===Imaging=== | ===Imaging=== | ||
Parameters to assess | Parameters to assess by echocardiography include: | ||
* [[End-diastolic diameter]] | *[[End-diastolic diameter]] | ||
*[[End systolic diameter]] | |||
*[[Ejection fraction]] | |||
Echocardiography can also be used to assess the ascending aorta (root) and/or valve causes of insufficiency. | |||
Echocardiographic findings correlated with severe AR include: | |||
* AR color jet dimension/left ventricular outflow tract diameter >60% | * AR color jet dimension/left ventricular outflow tract diameter >60% | ||
* Flow reversal in proximal [[descending thoracic aorta]] | * Flow reversal in proximal [[descending thoracic aorta]] | ||
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* Regurgitant fraction >55% | * Regurgitant fraction >55% | ||
If | If the color flow on echocardiography is solely taken into consideration during the evaluation of aortic regurgitation, echocardiographic findings might underestimate or overestimate the severity of the regurgitation. Thus, it is recommended to use cardiac catheterization as an imaging modality. When discrepancy exists between the findings of echocardiography and that of the cardiac catherization, it is recommended to do a left ventriculogram . | ||
* Treadmill testing in aortic regurgitation is used to get objective measurement of exercise capacity. | * Treadmill testing in aortic regurgitation is used to get objective measurement of exercise capacity. | ||
* [[Magnetic resonance angiogram]] ([[MRA]]) and [[CT]] are used to scan the entire aorta | * [[Magnetic resonance angiogram]] ([[MRA]]) and [[CT]] are used to scan the entire aorta when [[bicuspid aortic valve]] is present. | ||
==Treatment== | ==Treatment== | ||
===Acute severe Aortic insufficiency=== | ===Acute severe Aortic insufficiency=== | ||
* Urgent surgical intervention is generally indicated especially type A dissection and acute prosthetic AR. | * Urgent surgical intervention is generally indicated especially in the cases of type A aortic dissection and acute prosthetic AR. | ||
* [[Nitroprusside]] and [[ionotropes]] can be used to maintain [[blood pressure]]. | * [[Nitroprusside]] and [[ionotropes]] can be used to maintain [[blood pressure]]. | ||
* Treatment options that are contraindicated include: | * Treatment options that are contraindicated include: | ||
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===Chronic Aotic insufficiency=== | ===Chronic Aotic insufficiency=== | ||
Vasodilator therapy for severe chronic aortic insufficiency | *Vasodilator therapy is indicated for the treatment of severe chronic aortic insufficiency in: | ||
* | **Patients with symptoms and/or left ventricular ejection fraction ≤50% and who are not candidates for aortic valve replacement. | ||
* Asymptomatic patients with [[AR]] and [[hypertension]]. | **Asymptomatic patients with [[AR]] and [[hypertension]]. | ||
*Vasodilator therapy is not indicated for other patients with AR. | |||
Vasodilator therapy is not indicated for | |||
===Indications for Surgery=== | ===Indications for Surgery=== | ||
Revision as of 14:17, 16 October 2012
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Aortic Regurgitation Microchapters |
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Raviteja Guddeti, M.B.B.S. [2]
Overview
Aortic insufficiency is a valvular disease defined as the inability of the aortic valve to close tightly leading to a backward flow of blood from the aorta into the left ventricle during diastole.
Classification
Aortic insufficiency can be acute or chronic.
Pathophysiology
During acute aortic regurgitation, there is a sudden large regurgitant volume of blood imposed on the unprepared left ventricle. Because of the acute nature of the onset of the regurgitation, there will be no ventricular dilatation. As the blood flow through the aorta is reversed, the effective left ventricle stroke volume is reduced. As a result, the left ventricular end diastolic pressures will increase and consequently pulmonary edema may occur.
Causes
Aortic insufficiency can be caused by defects in the intrinsic valve or the ascending aorta (root).
- Defects in the Intrinsic Valve:
- Degenerative / calcific aortic valve
- Endocarditis
- Bicuspid aortic valve
- Rheumatic fever
- Valvulitis
- Anorectic drugs
- Defecst in the Ascending Aorta (Root):
- Degenerative
- Type A aortic dissection
- Marfan syndrome
- Giant cell arteries
- Inflammatory:
Differentiating Aortic insufficiency from Mitral regurgitation
Natural History
There are two main parameters that reflect the overall outcome in patients with aortic insufficiency:
- Ejection fraction
- End systolic diameter
Left ventricular dysfunction develops in patients with aortic insufficiency after decades of the onset of the symptoms. This lag period is longer than that of mitral regurgitation.
The lower the ejection fraction is, the poorer the outcome is.
Diagnosis
Symptoms
Acute aortic insufficiency may present with the following symptoms:
- Sudden onset of severe breathlessness (dyspnea)
- Chest pain if aortic dissection is the cause of insufficiency.
Chronic aortic insufficiency causes:
Patients having bicuspid aortic valve should be evaluated for coarctation of aorta if hypertension is present and for dissection of aorta if chest pain is present. Therefore the entire aorta should be scanned either by an magnetic resonance angiogram (MRA) or computed tomography (CT).
Physical Examination
- Bounding pulses may be present
- Head nodding (de Musset's sign) - rhythmic nodding or bobbing of the head in synchrony with the beating of the heart.
- Capillary pulsations (Quincke's sign) - pulsation of arteriolar and venous plexuses of the nail bed causing alternate blanching and flushing.
- Corrigan's pulse - rapid carotid upstroke, rapid collapse
- Duroziez's sign - 'pistol' shot sounds (audible diastolic murmur heard over the femoral artery.
- Early diastolic murmur best heard in the right second intercostal space. The murmur may be soft in acute AR.
- S3 and S4 may be heard.
Imaging
Parameters to assess by echocardiography include:
Echocardiography can also be used to assess the ascending aorta (root) and/or valve causes of insufficiency.
Echocardiographic findings correlated with severe AR include:
- AR color jet dimension/left ventricular outflow tract diameter >60%
- Flow reversal in proximal descending thoracic aorta
- Regurgitant volume >60 ml
- Regurgitant fraction >55%
If the color flow on echocardiography is solely taken into consideration during the evaluation of aortic regurgitation, echocardiographic findings might underestimate or overestimate the severity of the regurgitation. Thus, it is recommended to use cardiac catheterization as an imaging modality. When discrepancy exists between the findings of echocardiography and that of the cardiac catherization, it is recommended to do a left ventriculogram .
- Treadmill testing in aortic regurgitation is used to get objective measurement of exercise capacity.
- Magnetic resonance angiogram (MRA) and CT are used to scan the entire aorta when bicuspid aortic valve is present.
Treatment
Acute severe Aortic insufficiency
- Urgent surgical intervention is generally indicated especially in the cases of type A aortic dissection and acute prosthetic AR.
- Nitroprusside and ionotropes can be used to maintain blood pressure.
- Treatment options that are contraindicated include:
- Intra aortic balloon pump
- Pressors
- Beta blockers
Chronic Aotic insufficiency
- Vasodilator therapy is indicated for the treatment of severe chronic aortic insufficiency in:
- Patients with symptoms and/or left ventricular ejection fraction ≤50% and who are not candidates for aortic valve replacement.
- Asymptomatic patients with AR and hypertension.
- Vasodilator therapy is not indicated for other patients with AR.
Indications for Surgery
Indications for surgery in aortic insufficiency include:
- Very severe insufficiency
- Any symptoms
- Ejection fraction <50%
- End systolic dimension >50 mm