Aortic Stenosis Flashcards
What is aortic stenosis?
Obstruction of blood flow across the aortic valve due to pathological narrowing.
What are the risk factors for atrial stenosis?
- Advanced age
- Congenitally bicuspid valve
- Rheumatic fever
- Chronic kidney disease
What is the most common cause of aortic stenosis?
Calcification of normal trileaflet valves
What are the signs of aortic stenosis?
- Ejection systolic murmur
- S2 diminshed and single
- Slow rising pulse with narrow pulse pressure
- Heaving, non-displaced apex beat
- LV heave
- Aortic thrill
What are the symptoms of aortic stenosis?
- Dyspnoea
- Chest pain
- Syncope
What investigations should be ordered for aortic stenosis?
- Transthoracic echocardiogram (including Doppler)
- ECG
- CXR
- Cardiac catherisation
Why investigate transthoracic echocardiogram (including Doppler)?
Transthoracic Doppler echocardiography is the best test for the initial diagnosis and subsequent evaluation of AS.
May show elevated aortic pressure gradient; measurement of valve area and left ventricular ejection function.
Why investigate using ECG?
The ECG is abnormal in >90% of patients with AS, with the most common abnormality being left ventricular hypertrophy (LVH) due to pressure overload.
May demonstrate left ventricular hypertrophy and absent Q waves, atrioventricular block, hemiblock or bundle branch block.
Why investigate CXR?
May show left ventriculat hypertrophy or calcified aortic valve.
Why investigate using cardiac catherisation?
Catheterisation allows for direct measurement of the pressure gradient. Due to the invasive nature, this test is useful for diagnosis only when the echocardiogram is inconclusive or discrepant from other findings.
Elevated aortic pressure gradient.
Briefly describe the treatment for aortic stenosis
Conventional treatment for patients aortic stenosis is surgical aortic valve replacement (SAVR).
Transcatheter aortic valve implantation (TAVI) for aortic stenosis is an alternative for patients for whom surgery is unsuitable, but it does not allow for concomitant coronary artery bypass grafting.
What are the complications of aortic stenosis?
- Acute congestive heart failure
- Sudden cardiac death
- Infection of prosthetic valve
What differentials should be considered for aortic stenosis?
- Aortic sclerosis
- Ischemic heart disease
- Hypertrophic cardiomyopathy (HMC)
How does aortic stenosis and aortic sclerosis differ?
Differentiating signs and symptoms:
- The murmur of aortic sclerosis is typically less intense and non-radiating and the S2 is normal and physiologically split
- Signs and symptoms of heart failure or chest pain should prompt an echocardiogram but cannot by themselves reliably distinguish the two conditions
Differentiating investigations:
- Transthoracic Doppler echo will demonstrate no significant pressure gradient (<5 mmHg) across the aortic valve with aortic sclerosis
How does aortic stenosis and ischemic heart disease differ?
Differentiating signs and symptoms:
- AS and coronary artery disease frequently co-exist and it is difficult to determine their relative contributions to cardiac complaints when both are present in the same patient
Differentiating investigations:
- In ischaemic heart disease: common ECG findings include Q waves in contiguous leads, and the echocardiogram often shows segments of the myocardium with abnormal systolic thickening or wall motion abnormalities
- In AS: Q waves are absent in the ECG; regional wall motion abnormalities are absent on the echocardiogram; and coronary arteries are normal upon cardiac catheterisation
