Valvular Heart disease Flashcards
What does the mitral valve consist of (anatomy)?
Fibrous annulus, anterior and posterior leaflets, chord tendineae and the papillary muscle
What is mitral stenosis?
Narrowing (stenosing) of valve orifice area <2cm.
Normal orifice area = 4-6cm
What is the most common cause of mitral stenosis?
Due to rheumatic heart disease following previous rheumatic fever due to group A beta-haemolytic streptococcus.
What changes are seen in the mitral stenosis following rheumatic heart disease?
Leads to valve thickening, cusp fusion, calcium deposition and a stenotic (narrowed) valve orifice over many years.
What are some other causes of mitral stenosis?
Congenital
Mitral annular calcification (elderly)
Carcinoid tumours metastasising to the lung
Prosthetic valve
What is the underling pathology as a result of mitral stenosis?
Severe mitral stenosis (v narrow valve orifice) => increased left atrial pressure (to maintain cardiac output) => left atrial hypertrophy and dilation => loss of coordinated atrial contraction => atrial fibrillation with tachycardia
As a result, pulmonary and right heart pressure also increase => pulmonary oedema + hypertension => right ventricular hypertrophy, dilation and failure => tricuspid regurgitation
What are the clinical signs and symptoms of mitral stenosis?
Symptoms:
Pulmonary hypertension => Severe dyspnoea, frothy sputum or frank haemoptysis (bloody but small vol), productive cough - blood tinged
Pressure from enlarged left atrium on nearing structures => hoarseness (recurrent laryngeal nerve), dysphagia (oesophagus), bronchial obstruction
Fatigue, palpitations, chest pain
AF => systemic emboli => stroke
Infective endocarditis (rare)
Signs:
Malar flush (due to reduced CO)
Atrial fibrillation (irregularly irregular, low volume pulse)
Tapping non-displaced apex beat (palpable S1)
Right ventricle heaving, sustained
On auscultation: Loud S1, opening snap, rumbling mid-diastolic murmur (heard best on expiration with patient on left side)
JVP raised if right heart failure
*The more severe the stenosis the longer the diastolic murmur and closer the opening tap is to S2.
Who does it affect?
Women > Men
Rheumatic fever common in low-middle income countries => increased risk of mitral stenosis
Which investigations are carried out for mitral stenosis?
- Chest X-ray : enlarged left atrium (double shadow in right cardiac silhouette) ; mitral valve calcifications ; pulmonary oedema
- ECG : Atrial fibrillation ; P mitrale (biphasic p-wave i.e. double bump p-wave seen in left atrium enlargement);
- Echocardiogram : determines left atrial size and thickening, any calcification and mobility of mitral leaflets.
What is the normal size of mitral valve orifice?
What size of mitral valve orifice do symptoms arise?
4-6cm/sq
Symptoms arise at <2cm/sq
Which investigation is diagnostic of mitral stenosis?
Echo - significant stenosis if valve orifice <1cm/sq
What is the indication for catheterisation?
Severe mitral stenosis + calcifications, previous valvotomy, other valve disease, angina, severe pulmonary hypertension
How do you manage mitral stenosis and its signs i.e. AF?
AF: rate control with beta-blockers or DC cardioversion
Anti-coagulation (warfarin) for atrial thrombus prevention and systemic emboli.
Diuretics to reduce preload and pulmonary venous congestion
There are 4 interventions which may be carried out if medical therapy fails to control mitral stenosis symptoms.
Explain briefly trans-septal balloon valvotomy.
Which patients is it ideal for?
What are the risk of this procedure?
What are the contra-indications?
- Trans-septal balloon valvotomy: catheter via femoral vein through atrial septum => balloon splits up the commissures.
- Ideal for patients with pliable valves
- Risk of significant mitral regurgitation => valve replacement
- Contraindications: heavy calcifications or mitral regurgitation and thrombus in left atrium.
* Transoesphageal echo prior to this procedure to exclude atrial thrombus
There are 4 interventions which may be carried out if medical therapy fails to control mitral stenosis symptoms.
Explain briefly closed valvotomy.
Which patients is it ideal for?
Fused cusps are forced apart using a dilator via the apex of the left ventricle.
Only suitable for patients with mobile, non-calcified and non-regurgitating mitral valves.
*Good result for 10 years
There are 4 interventions which may be carried out if medical therapy fails to control mitral stenosis symptoms.
Explain briefly open valvotomy.
What are its benefits vs closed valvotomy?
Cusps are dissected apart. Cardiopulmonary bypass is required.
Open dissection reduces the likelihood of causing traumatic mitral regurgitation.
*preferred to closed valvotomy
There are 4 interventions which may be carried out if medical therapy fails to control mitral stenosis symptoms.
What is the indication for mitral valve replacement?
- Mitral regurgitation is present alongside mitral stenosis
- Badly diseased/calcified stenotic valve that can’t be reopened without significant regurgitation
- Severe mitral stenosis and thrombus in left atrium despite anti-coagulant.
* Artificial valves lasts for 20 years + anti-coagulation to prevent thrombus formation
What is mitral regurgitation?
Backflow through the mitral valve during systole.
What is the underlying pathology as a result of mitral regurgitation?
Regurgitation into the left atrium => left atrial dilation => left ventricle enlargement/hypertrophy/failure
In acute mitral regurgitation, left atrium doesn’t have time to dilate => increases left atrium pressure => increases pulmonary venous pressure => pulmonary oedema
Mitral regurgitation occurs due to abnormalities of the valve leaflets, annulus, chordae tendineae or papillary muscle.
What are the causes of mitral regurgitation?
Left ventricle dilation (functional)
Annular calcifications (elderly)
Rheumatic heart disease
Infective endocarditis
Ischaemic heart disease
Cardiomyopathy (dilated or hypertrophy)
Collagen disease i.e. Marfan’s, Ehlers Danlos syndrome
Degenerative (myoxomatous) disease => valves becomes thickened with nodule formation => prevents them from closing properly => regurgitation
What are the signs and symptoms of mitral regurgitation?
Symptoms:
Dyspnoea and Orthopnoea => due to pulmonary venous hypertension
- direct from mitral regurgitation
- secondarily from left ventricular failure
Fatigue & Lethargy => due to reduced cardiac output
Palpitations
Symptoms of right heart failure in late disease
Subacute infective endocarditis
Signs:
Laterally displaced hyper dynamic apex beat + systolic thrill if severe
Pansystolic murmur at apex radiating to axilla
Soft S1, split S2, loud P2 => pulmonary hypertension
Atrial fibrillation
Which investigations are carried out for mitral regurgitation?
- ECG: P-mitrale (bifid p-wave = atrial enlargement i.e. dilation or hypertrophy), atrial fibrillation, tall R-waves in left lateral leads I & V6 = left ventricular hypertrophy
* LVH present in 50% of mitral regurgitation - Chest X-ray: Left atrial and ventricular enlargement, valve calcifications, pulmonary oedema
- Echocardiogram: Dilated left atrium and ventricle, chordal or papillary rupture. Severity of regurgitation assessed using colour doppler.
* Echo assesses LV function, mitral regurgitation severity and aetiology - Cardiac catheterisation: to confirm diagnosis and exclude other valve disease. Appropriate for valve repair/replacement.
What is the conservative management for mitral regurgitation?
Mild-moderate mitral regurgitation = conservative management
- AF: control rate if fast
- Anticoagulate if AF, history of embolism, prosthetic valve, additional mitral stenosis
- Diuretics improve symptoms
- Prophylaxis against endocarditis
- Regular echo monitoring