valvular heart disease Flashcards
describe the mitral valve?
Fibrous annulus, anterior and posterior leaflets, chordae, tendinae and papillary muscles
what is the most common cause of mitral stenosis?
- rheumatic heart disease secondary to previous rheumatic fever due to infection with group A beta-hemolytic streptococcus
- women > men
- inflammation-> commissural fusion and reduction in mitral valve orifice->doming pattern on echo -> thickening of valve, cusp fusion, calcium deposition, narrowed stenotic valve orifice and immobility of valve cusps
what are the other causes of mitral stenosis?
- Lutemacher’s syndrome
- Congenital mitral stenosis
- Carcinoid tumours metastasizing to lung or primary bronchial carcinoid
- what is the normal mitral valve orifice area
2. and what is it in a patient with mitral stenosis?
- 4-6cm2
2. <1cm2
describe the pathophysiology of mitral stenosis?
- mitral valve orifice reduced
- for cardiac output to be maintained the left atrial pressure increases and left atrial hypertrophy and dilatation occur
- increase in pulmonary venous, pulmonary arterial and right heart pressure increases
- development of pulmonary oedema especially when in AF and tachycardia
- this is prevented by alveolar and capillary thickening and pulmonary arterial vasoconstriction
- pulmonary hypertension causes right ventricular hypertrophy, dilation and failure with tricuspid regurgitation
where is the mitral valve located?
left side of the heart between atrium and ventricle
when will a patient with mitral stenosis start to experience symptoms?
- until valve orifice is moderately stenosed (area=2cm2)
- usually not till several decades after attack of rheumatic fever
what are the symptoms of mitral stenosis and what causes them?
- progressive severe dyspnoea (pulmonary venous hypertension and recurrent bronchitis)
- productive cough-blood, frothy sputum, frank haemoptysis
- weakness, fatigue and abdominal swelling due to right heart failure due to pulmonary hypertension
- palpitations due to large atrium and AF
what signs would be seen In the face of a patient with mitral stenosis?
malar flush (bilateral, cyanotic, dusty pink discolouration over upper cheeks due to arteriovenous anastomoses and vascular stasis
describe the pulse of a patient with mitral stenosis?
small volume pulse
usually regular
mostly in sinus rhythm but may develop AF
what signs would be seen in jugular veins in a patient with mitral stenosis?
- if right heart failure develops-obvious distension of jugular veins
- if pulmonary hyertension or tricuspid stenosis present then ‘a wave’ will be prominent
what signs would be noted on palpation in a patient with mitral stenosis?
tapping impulse felt parasternally on left
what would be the auscultation findings in a patient with mitral stenosis?
- loud first heart sound if mitral valve is pliable
- opening snap heard due to increased left atrial pressure, followed by a low pitched rumbling mid diastolic murmur (best heard when patient lies on left side)
- if in sinus rhythm-louder at end of diastole.
- severity of mitral stenosis is judged based on criteria
what criteria is used to judge the severity of mitral stenosis?
- presence of pulmonary hypertension (severe, right ventricular heave)
- closeness of opening snap to second heart sound proportional to severity
- length of mid-diastolic murmur proportional to severity
- as valve cusps become immobile the loud first heard sound softens and opening snap disappears
what investigations should be considered in a patient with mitral stenosis?
- CXR
- ECG
- echo
- cardiac magnetic resonance
- cardiac catheterisation
what are CXR findings in a patient with mitral stenosis?
- small heart and enlarged left atrium
- usually have pulmonary venous hypertension
- calcified mitral valve
- signs of pulmonary oedema
what are ECG findings in patients with mitral stenosis?
- in sinus rhythm will show a bifid p wave due to delay of left atrial activation
- AF usually present
- as disease progresses-ECG may show right ventricular hypertrophy (right axis deterioration and tall R waves in V1)
what is the purpose of echo in a patient with mitral stenosis?
- Determine left and right atrial and ventricular size and function
- Severity of mitral stenosis can be defined by planimetry of the mitral valve area.
- Wilkins score-determine if valve is suitable for percutaneous valvotomy
- Continuous wave doppler can estimate pulmonary artery pressure
what is the purpose of cardiac magnetic resonance in patients with mitral stenosis?
show mitral valve anatomy
describe the role of cardiac catheterisation in patients with mitral stenosis?
- only used if co-existing cardiac problem suspected
- Right heart catheterisaton may be required to determine pulmonary artery pressure
what are the treatment options for mitral stenosis?
- mild may not need treatment
- early symptoms such as mild dyspnoea can be treated with low dose diuretics
- pulmonary hypertension-surgical relief
- operative measures
what are the 4 operative measures used in treatment of mitral stenosis?
- trans-septal balloon valvotomy
- closed valvotomy
- open valvotomy
- mitral valve replacement
describe trans septal balloon valvotomy?
- Catheter into right atrium via femoral vein under local anaesthetic in cardiac catheter laboratory
- Interatrial septum is punctured and catheter advanced into left atrium and across mitral valve
- Balloon is passed over catheter to lie across the valve and inflated
- Can result in regurgitation and need valve replacement
what patients is trans septal balloon valvotomy good in?
Good for patients with pliable valves with little involvement of subvalvular apparatus and with minimal mitral regurgitation
what are the contraindications for trans septal balloon valvotomy?
heavy calcification or more than mild mitral regurgitaton and throbus
what patients is closed valvotomy used in?
For patients with mobile, non-calcified and non-regurgitant miral valves
describe the process of closed valvotomy?
- Fused cusps are forced apart by dilator introduced through apex of left ventricle
- Valve cusps often re-fuse and another operation may be needed
what is open valvotomy?
Cusps are carefully dissected apart under direct vision
describe the benefit of open valvotomy?
- often preferred to closed valvotomy
- requires cardiopulmonary bypass
- reduces likelihood of causing traumatic mitral regurgitation
when is mitral valve replacement necessary?
- Mitral regurgitation is present
- Badly diseased or badly calcified stenotic valve that cannot be reopened without producing significant regurgitation
- Moderate or severe mitral stenosis and thrombus in left atrium despite anticoagulation
how long can artificial valves work for?
> 20 years
what medications do patients require following mitral valve replacement?
anticoagulants to prevent thrombus formation
what is the most common cause of mitral regurgitation?
degenerative (myxomatous) disease, ischaemic heart disease, rheumatic heart disease and infectious endocarditis.
other than the most common causes what are the other causes of mitral regurgitation?
- can occur due to abnormalities of valve leaflets, the annulus, chordae tendineae or papillary muscles or left ventricle
- Also seen in diseases of myocardium (dilated and hypertrophic cardiomyopathy), rheumatic autoimmune disease eg systemic lupus erythematosus, collagen disesaes eg Marfan’s and ehlers-danlos syndromes and drug including centrally acting appetite suppressants and dopamine agonists
describe the pathophysiology of mitral regurgitation?
Regurgitation into left atrium produces left atrial dilation but little increases in left atrial pressure if long standing
Acute regurgitation-normal compliance of left atrial pressure rises so left atrial v-wave is increased and pulmonary venous pressure rises to produces pulmonary oedema. Since a proportion of stroke volume is regurgitated the stroke volume increases to maintain cardiac output and therefore left ventricle enlarges
what classification system can be used in mitral regurgitation?
Carpentier classification uses mitral leaflet motion to divide patients into classes according to mechanism of regurgitaton which is useful when considering surgery needed
when do patients with mitral regurgitation experience symptoms?
can be present for years with increased cardiac dimensions before symptoms occur
what symptoms may a patient with cardiac regurgitation experience?
- palpitation (due to increased stroke volume)
- dyspnoea and orthopnoea (due to venous hypertension)
- fatigue and lethargy (due to reduced cardiac output)
- late stages-symptoms of right heart failure and lead to congestive cardiac failure
- cardiac cachexia
- thromboembolism less common than mitral stenosis
- subacute infective endocarditis more common
what signs may a patient with mitral regurgitation experience?
- laterally displaced diffuse apex beat
- systolic thrill
- soft first heart sound (incomplete apposition of valve cusps and partial closure by ventricular systole)
- parasystolic murmur loudest at apex but radiating widely over precordium and axilla
- mid systolic click due to sudden prolapse of valve
- prominent 3rd heart sound due to rush of blood into dilated left ventricle in early diastole
what investigations should be carried out in a patient with mitral regurgitation?
- CXR
- ECG
- echo
- cardiac catheterisation
what may CXR show in a patient with mitral regurgitation?
left atrial and left ventricular enlargement
-increase in CTR and valve calcification
what would ECG show in a patient with mitral regurgitation?
hows features of left atrial delat (bifid p waves) and left ventricular hypertrophy (manifested by tall R waves in left lateral leads) and deep S waves in right sided precordial leads. Left ventricular hypertrophy occurs in about 50% of patients with mitral regurgitation. AF may be present
what would echo show in a patient with mitral regurgitation?
dilated left atrium and left ventricle. May be specific features of chordal or papillary muscle rupture. Assess the severity of regurgitation by colour doppler and looking at size of jet area and size of vena contracta and calculating regurgitant fraction, volume or orifice area. Observe dynamics of ventricular function. Transoesophageal echocardiography can be helpful to identify structural valve abnormalities before surgery
describe cardiac catheterisation in patients with mitral regurgitation?
prominent left atrial systolic pressure wave and when contrast is injected into the left ventricle it is seen regurgitating into an enlarged left atrium during systole
how is mitral regurgitation managed in mild cases?
in absence of symptoms can be managed conservatively and prophylaxis against endocarditis and serial echos
what intervention would be indicated if there was evidence of progression of mitral regurgitation?
early surgical intervention (mitral valve repair or replacement)
the advantages of surgery are diminished in more advanced disease
for patients with Mitral regurgitation who are unsuitable for surgery what management should be considered?
ACE inhibitors
diuretics
anticoagulants
percutaneous mitral valve repair
what is the aortic valve?
semilunar valve
between left ventricle and aorta
what is aortic stenosis?
- Chronic progressive disease producing obstruction to left ventricular stroke volume causing symptoms of chest pain, breathlessness, syncope, pre-syncope and fatigue
- calcific stenosis of a trileaflet aortic valve, stenosis of a congenitally bicuspid valve and rheumatic aortic stenosis
what is the commonest cause of aortic valve stenosis?
- calcific aortic valvular disease
- mainly in elderly-inflammatory process including macrophages and T lymphocytes with initially thickening of subendotheliam with fibrosis. Lesions contain lipoproteins which calcify, increasing leaflet stiffness and reduce systolic opening
what are the causes of aortic stenosis?
-calcific aortic valvular disease bicuspid aortic valve 1-2% of births associated with aortic dissection need regular echos -rheumatic fever-progressive fusion, thickening and calcification of aortic valve -chronic kidney disease -Paget's disease of bone -radiation exposure -homozygous familial hypercholesterolaemia
other than aortic stenosis what are the causes of obstruction to left ventricular emptying?
- supravalvular obstruction
- hypertrophic cardiomyopathy
- subvalvular aortic stenosis
describe the pathophysiology of aortic stenosis?
- Obstructed left ventricular emptying leads to increased left ventricular pressure and compensatory left ventricular hypertrophy
- Results in ischaemia of the left ventricular myocardium and angina, arrythmias and left ventricular failure
- Obstruction to emptying is more severe on emptying
- Normally exercise causes an increased cardiac output but due to narroeing of aortic valve orifice the cardiac output can hardly increase so BP falls, coronary ischaemia worsens, myocardial fails and cardiac arrythmias develop
- Left ventricular systolic function is typically preserved in patients with aortic stenosis
what are the symptoms of aortic stenosis?
- Usually none unless aortic stenosis is moderately severe
- Exercise induced syncope, angina and dyspnoea
- Once symptoms occur the prognosis is poor (death within 2-3 years with no surgical intervention
describe the pulse of a patient with aortic stenosis?
small volume
slow rising or plateau
describe precordial palpation in a patient with aortic stenosis?
apex not usually displaced because hypertrophy doesn’t produce noticeable cardiomegaly. Pulsation is sustained and obvious. Double impulse sometimes felt because of fourth heart sound or atrial contraction may be palpable. Systolic thrill may be felt in aortic area
describe what would be heard on auscultation in a patient with aortic stenosis?
ejection systolic murmur which is usually diamond shaped (crescendo-decrescendo). Murmur is usually longer when disease is more severe, as a longer ejection time is needed. Murmur is usually rough in quality and best heard in aortic area. Intensity of murmur is not a good guide to severity of condition as it is lessened by reduced cardiac output. In severe disease it may be inaudible. Other findings; systolic ejection click, soft or inaudible aortic second heart sound, reversed splitting of second heart sound, prominent fourth heart sound
what investigations should be done in a patient with aortic stenosis?
- CXR
- ECG
- echo
- cardiac catheterization
- cardiac magnetic resonance and cardiac CT
what would be seen on CXR in a patient with aortic stenosis?
relatively small heart with a prominent, dilated, ascending aorta. Due to turbulent blood flow above stenosed aortic valve produces so-called ‘post-stenotic dilatation’. The aortic valve may be calcified. CTR increases when heart failure occurs.