Aortic Insufficiency
Definition
The backflow of blood through the aortic valve during diastole, may be acute or chronic.
Acute : Etiology
- Infective endocarditis
- Dissection of the ascending aorta
- Catheter balloon valvuloplasty
- Trauma
Chronic : Etiology
- Rheumatic fever
- Marfan's syndrome
- Hypertension
- Bicuspid aortic valve
- Membranous ventricular septal defect
- Ascending aortic aneurysm
- Aortic valve prolapse
Signs and Symptoms
- Exertional dyspnea
- Chest pain (angina)
- Dizziness
- Syncope
Complications
- Left ventricular volume overload with left ventricular dilatation
- Decreased left ventricular systolic function (late in course)
- Congestive heart failure
- Increased risk of infective endocarditis
Cardiac Auscultation
- A high-pitched, blowing, diastolic decrescendo murmur heard best along the left sternal border
- An Austin Flint murmur, associated with severe aortic insufficiency and described as a low-pitched mid-diastolic rumble at the apex
- Bisferien's pulse (widely notched arterial pulse, sometimes palpable)
Electrocardiogram
- Left ventricular hypertrophy
- Left atrial enlargement
Chest X-ray
- Cardiomegaly (cor bovinum)
- Dilated aortic root
Cardiac Catheterization
- Supravalvular angiography allows assessment of severity
Quantification of Aortic insufficiency by Cardiac Catheterization
- Mild (grade 1+) : A small amount of contrast enters the left ventricle during diastole and clears with each systole.
- Moderate (grade 2+) : More contrast enters with each diastole and faint opacification of the entire left ventricular chamber occurs
- Moderately severe (grade 3+) : Left ventricular chamber is well opacified and equal in density when compared with the ascending aorta
- Severe (grade 4+) : Complete, dense opacification of the ventricular chamber on the first beat, and the left ventricle is more densely opacified than the ascending aorta
Treatment
- Digitalis and/or diuretics for congestive heart failure
- Aortic valve repair or replacement when indicated (left ventricular end-systolic dimension > 55 mm and a percent left ventricular fractional shortening of < 25% may indicate a need for AVR)
Aortic insufficiency Severity Scales
PW Doppler: mapping technique
- Physiologic : Duration of regurgitant jet <80 msec
- Mild (grade 1+) : The regurgitant jet extends to just beneath the aortic leaflets
- Moderate (grade 2+) : The regurgitant jet extends to the tips of the mitral leaflets
- Moderately severe (grade 3+) : The regurgitant jet extends to the papillary muscle level
- Severe (grade 4+) : The regurgitant jet extends beyond the papillary muscle level
CW Doppler: Spectral strength of regurgitant jet
- Grade 1+ : Spectral tracing stains sufficiently for detection, but not enough for clear delineation
- Grade 2+ : Complete spectral tracing can just be seen
- Grade 3+ : Distinct darkening of spectral tracing is visible, but density is less than antegrade flow
- Grade 4+ : Dark-stained spectral tracing
Color flow Doppler
Jet height / LVOT height
- Mild (1+) : < 25%
- Moderate (2+) : 25 to 46%
- Moderately severe (3+) : 47 to 64%
- Severe (4+) : ≥ 65%
Regurgitant jet area/LVOT area
- Mild(1+) : < 4%
- Moderate (2+) : 4 to 24%
- Moderately severe (3+) : 25 to 59%
- Severe (4+) : ≥ 60%
M-Mode
- Diastolic flutter of the anterior mitral valve leaflet, posterior mitral valve leaflet, chordae tendineae, papillary muscle, and/or the interventricular septum
- Diastolic "damping" of the anterior mitral valve leaflet
- Diastolic flutter of the aortic valve
- Lack of aortic valve coaptation during diastole
- Left ventricular volume overload pattern (defined as hyperkinesis of the left ventricular walls with left ventricular dilatation)
- Increased left ventricular mass
- Premature closure of the mitral valve┼(defined as the C point of the mitral valve occurring on or before the onset of the QRS complex
- Premature opening of the aortic valve (defined as occurring when the aortic valve opens on or before the onset of the QRS complex)
2-D
- Anatomic basis for the presence of aortic insufficiency (e.g. Flail aortic valve, ascending aortic aneurysm)
- Incomplete closure of the aortic valve cusps (> 2 mm) as seen on parasternal short-axis view of the aortic valve
- Diastolic flutter of the anterior mitral valve leaflet
- Reverse "doming" of the anterior mitral valve leaflet (associated with 3+ or 4+ aortic insufficiency)
- Left ventricular volume overload pattern
PW Doppler
- Determine the severity of the aortic insufficiency jet by the mapping technique (see table)
- Determine the regurgitant fraction
- A shortened deceleration time of the mitral valve inflow (< 150 msec) with an increased mitral E/A ratio indicates significant aortic insufficiency (usually associated with severe acute AR)
CW Doppler
- Compare the regurgitant Doppler spectral display with the aortic outflow Doppler spectral display
- Determine the slope of the aortic insufficiency spectral display. In general, the steeper the slope, the more severe the aortic insufficiency; a slope > 3 m/sec may indicate 3+ or 4+ aortic insufficiency
- Determine the pressure half-time of the aortic insufficiency spectral display. In general, a pressure half-time < 300 msec indicates significant aortic insufficiency.
Color Flow Doppler
- Determine the regurgitant jet height/LVOT height in the parasternal long-axis view
- Determine the regurgitant jet area/LVOT area in the parasternal short-axis view of the aortic valve
- Proximal acceleration (flow convergence) indicates aortic insufficiency is 3+ or 4+
- Reversal of flow in the descending thoracic aorta and/or abdominal aorta indicates aortic insufficiency is 3+ or 4+. May also be detected by PW or CW Doppler.
Important to Note:
- Determine the precise etiology of aortic insufficiency.
- In patients with significant chronic aortic insufficiency, carefully evaluate left ventricular dimension and function.
- In patients with severe acute aortic insufficiency, note the presence or absence of premature closure of the mitral valve, premature opening of the aortic valve, and/or a mitral valve deceleration time < 150 m/sec with increased E/A ratio.