Aortic stenosis

From Wikiecho

Aortic stenosis is a valvular heart disease resulting from the narrowing of aortic valve orifice.

Contents 1 Pathophysiology 2 Aetiology and echocardiographic features 2.1 Calcific aortic stenosis 2.2 Bicuspid aortic valve 2.3 Rheumatic heart disease 3 Differential diagnosis 4 Assessment by echocardiography 4.1 2D echocardiography 4.2 Doppler echocardiography 4.2.1 Peak Gradient 4.2.2 Mean Gradient 4.2.3 The continuity equation 4.2.4 Gorlin Equation 5 Severity summary

[edit] Pathophysiology

The haemodynamic hallmark of aortic stenosis is the elevated gradient across the aortic valve which can be indirectly measured with doppler echocardiography. When the aortic valve orifice becomes narrower, a pressure gradient develops between left ventricle and aorta. The left ventricle progressively hypertrophies, usually in a concentric manner to maintain the flow across the narrowed valve.

[edit] Aetiology and echocardiographic features

• Calcific aortic stenosis
• Bicuspid aortic valve
• Rheumatic aortic stenosis
• Congenital aortic stenosis

[edit] Calcific aortic stenosis

• Most common etiology in adults especially in the western world
• Age related calcification of normal tricuspid aortic valve
• Initially aortic valve sclerosis - increased echogenicity without a significant gradient.
• Systolic leaflet separation of  ≥ 15mm reliably severe stenosis.
• planimetry is not suitable in calcific aortic stenosis
• significant obstruction occurs around 70 - 85years.

[edit] Bicuspid aortic valve

• Affects 2% of the population
• Earlier presentation with secondary calcification at around 45 -65 year
• Eccentric closure line in M-mode echocardiography.
• Unequal size cusps
• Many have a raphe in the larger leaflet

[edit] Rheumatic heart disease

• Rheumatic aortic stenosis diagnosed when occurs with co-existent mitral valve disease, as Rheumatic heart disease preferentially affects the mitral valve.

• 2D - echocardiography shows

increased echogenicity along edges

commissural fusion

systolic doming

[edit] Differential diagnosis

• Fixed subvalvular obstruction

Presence of subaortic membrane

May be difficult to visualise in 2D echocardiography

Presents in early adulthood

Valve is not stenotic, but doppler shows increased gradient.

Can be diagnosed with careful search using pulse wave doppler and colour flow mapping

• Dynamic subaortic obstruction

Occurs with hypertrophic cardiomyopathy(HOCM)

Other features of HCM

late peaking, triangular CW doppler

changes with provocative measures

[edit] Assessment by echocardiography

[edit] 2D echocardiography

2D echocardiography of the aortic valve in the parasternal long axis view demonstrates right and non coronary leaflets. In the parasternal short axis view, leaflets open equally and forms a circular orifice during systole. During diastole, the normal leaflets form a three pointed star with prominence at the closing point. (nodules of Arentius)

[edit] Doppler echocardiography

[edit] Peak Gradient

[edit] Mean Gradient

[edit] The continuity equation

[edit] Gorlin Equation

[edit] Severity summary

Severity of aortic stenosis

Severity	mild	moderate	severe
Valve area	2.0 - 1.5	1- 1.5	<1
peak velocity (m/s)	2 -3	3-4	>4
Peak gradient (mmHg)	<35	35-65	>65
Mean gradient (mmHg)	<20	20-40	>40