Aortic Stenosis

Aortic Stenosis

·        Compared with regurgitation/incompetence:

o  Have different effects on the LV (can‟t have severe stenosis and severe regurgitation together):

o  Stenosis: ­pressure but no ­ in volume. LV tolerates pressure loads less well than volume loads ® stenosis is the worse of the two

o  Regurgitation: ­volume but no ­ in pressure. However, some ­ in afterload due to ­stroke volume

·        Causes or aortic stenosis:

o  Post inflammatory scarring (eg rheumatic fever): 10%

o  Senile (degenerative) aortic stenosis: commonest, in 8th – 9th decade

o  Calcification of deformed valve in 6th – 7th decade (associated with coarctation Þ check for radio-femoral delay)

o  Congenital stenosis

o  Infective

·        Symptoms:  Occur late

o  Dyspnoea and chest tightness related to exertion

o  Exertional syncope: due to inability to increase CO and transient ventricular arrhythmias

o  Angina pectoris/MI, fibrosis, ventricular arrhythmia and sudden death due to impact on myocardial

o   O2 supply and demand:

o   · ­­ O2 demand due to ­pressure and LV mass (­LV workload ® concentric hypertrophy) · ¯¯coronary blood flow due to ¯diastolic aortic pressure ­coronary vascular resistance and

§  ­systole compared with diastole ® ¯time for perfusion · ® ischaemia

o  No pulmonary oedema unless eg mitral problems secondary to LV hypertrophy, etc

·        Signs:

o  Sounds:

·        Harsh systolic ejection murmur (unless in severe LV failure) +/- systolic ejection click and a short aortic diastolic murmur. Heard in base, apex and carotids

·        May have paradoxic (reversed) splitting of S2 if severe stenosis or LBBB. 3rd and 4th sounds common

o  ¯Pulse pressure and low blood pressure

o   Slowing and shuddering of the carotid upstroke

o   LV hypertrophy on ECG or x-ray and heave on examination. Palpable LV hypertrophy with a dynamic quality is more related to incompetence – the ventricular impulse reflects stroke volume more than pressure

o   LV failure: progression from LV hypertrophy to LV dilation in late stages

o   AF in 10%

·        Diagnosis:

o   Often a discrepancy between symptoms and severity. Pre-symptomatic progression is highly variable

o   Usually at least some regurgitation as well

o   ECG: LV hypertrophy, occasionally left or right BBB

o   Pressure differential with Doppler ® estimate valve area

·        Gross:

o   Look for commissural fusion (rheumatic)

o   Heaped up calcified masses in leaflets. Beginning at the base Þ senile, beginning at the edge Þ abnormal valve

·        Management:

o   If mild/moderate (ie < 50 mmHg pressure gradient across the valve) then monitor

o   Fix/replace valve before LV failure

·        Complications:

o   Sudden death

o   LVF

o   Conduction defects

o   Infective endocarditis

o   Embolisation

·        Differential:

o   Can rarely be due to supraventricular or subvalvular lesions, with no problem with the valve

o   Left ventricular failure

o   Hypertrophic obstructive cardiomyopathy: pulse is jerky and upstroke rapid. Longer, harsher murmur best heard at the left sternal edge

o   Hard to confuse with mitral regurgitation (!!): Pansystolic murmur and rapid upstroke

o   Coarctation