2. Current Perspective of VHD
• VHD not as common as CAD, HF in Western Population
• Changing trends in the patient population and etiology
• Better understanding of pathophysiology
• Improved diagnostic modalities- echocardiography
• Varied treatment options- conservative surgical techniques and
percutaneous interventions
3. Cardiac murmurs
• Cardiac murmurs are often the first sign of underlying valvular
disease.
• May be systolic or diastolic, pathological or benign.
• Systolic murmurs may be due to physiological increases in
blood velocity or might indicate as yet asymptomatic cardiac
disease.
• Diastolic murmurs are usually pathological and require further
evaluation.
• ECG and CXR are readily available, but provide limited
information.
4. Echocardiography
Echocardiography can evaluate valve function by the
following imaging modalities:
• 2-D: Valve motion and morphology;
chamber size and function.
• Doppler: Blood flow velocity; valve
gradients; haemodynamic data.
• Colour flow: Valvular regurgitation
7. Management of cardiac murmurs
• Murmur + cardiac symptoms: refer to cardiologist.
• In asymptomatic patients with cardiac murmurs, an
echo is indicated in the following instances:
- Murmur + abnormal cardiac signs
- Murmur + abnormal ECG or CXR
- Diastolic or continuous murmurs
- Pansystolic or late systolic murmurs
9. Aortic stenosis
Aetiology
• Aortic stenosis may be congenital or acquired.
• Congenital malformations may be tricuspid, bicuspid or more
rarely unicuspid / quadricuspid
• Acquired causes include the following:
- Degenerative disease
- Rheumatic disease
- Calcific e.g. end-stage renal failure, Paget’s disease
- Miscellaneous e.g. rheumatoid involvement
12. Aortic stenosis
Symptoms
• Exertional dyspnoea or fatigue
• Angina
• Syncope
Physical findings
• Slow rising pulse
• Reduced systolic and pulse pressure
• Systolic thrill over the aortic area
• Ejection systolic, crescendo-decrescendo murmur
• Soft or inaudible second heart sound
• ECG: LVH, AV node conduction defects
13. Aortic stenosis
Echocardiography
• Thickened valves with reduced motion, sometimes calcified
• Grading of stenosis severity is as follows:
- Normal valve area = 3-4cm2
- Mild stenosis = 1.5-3cm2
- Moderate stenosis = 1.0-1.5cm2
- Severe stenosis ≤ 1.0cm2
• When stenosis is severe, the peak gradient across the aortic
valve is usually > 60mmHg.
17. Aortic stenosis
Medical therapy
• Conservative treatment should be offered for mild to
moderate aortic stenosis and to asymptomatic patients
with severe aortic stenosis as follows:
- Advise to report symptoms
- Avoid vigorous exercise
- Antibiotic prophylaxis for endocarditis
- Regular follow-up ± echocardiography
18. Aortic stenosis
Surgical/ Interventional therapy
• Aortic valve replacement should be offered to the following:
- Symptomatic pts with severe AS
- Pts with severe AS undergoing CABG surgery
- Pts with moderate AS undergoing CABG surgery
- Asymptomatic pts with severe AS and LV dysfunction
• Balloon valvuloplasty: bridge to surgery in haemodynamically
unstable patients, or palliation for patients with serious
comorbid conditions
• Transcatheter aortic valve replacement
19. Aortic stenosis
Aortic valve replacement
• In the absence of LV dysfunction, operative risk is
2-5%.
• Indicators of higher mortality are NYHA class, LV
dysfunction, age, concomitant coronary artery
disease, and aortic regurgitation.
• Valve replacement usually results in reduced LV
volumes, improved LV performance and regression
of LV hypertrophy.
20. Transcatheter Aortic Valve (TAVI)
• Novel alternative therapy
• Performed via femoral, subclavian or transapical
approaches
• Currently reserved for high risk, symptomatic severe
degenerative aortic stenosis
21. Aortic regurgitation
Aetiology
• Either due to primary disease of the aortic valve or wall of the
aortic root or both.
• Causes of primary aortic valve disease include:
- Congenital eg. bicuspid aortic valve
- Acquired: rheumatic valve disease, infective
endocarditis, trauma, connective tissue disease.
• Causes of primary aortic root disease include:
- Degenerative, cystic medial necrosis (eg. Marfan’s),
aortic dissection, syphilis, connective tissue disease,
hypertension.
22. Aortic regurgitation
Clinical history
• Chronic severe AR
Dyspnoea is the principal symptom
Syncope is rare and angina is less frequent than in
aortic stenosis.
• Acute severe AR
LV decompensation occurs readily with fatigue,
severe dyspnoea and hypotension.
23. Pathophysiology of aortic regurgitation
Aortic regurgitation
LV volume stroke volume diastolic BP
LV mass systolic BP
LV dysfunction myocardial ischaemia
LV failure
25. Aortic Regurgitation
• ECG: Left axis deviation, LV hypertrophy.
• CXR: Cardiomegaly, aortic calcification, aortic root dilatation
Echocardiography
• Colour flow
- width of the jet at its origin
- extent into the LV
• Doppler
- Rate of decline of aortic reguritant flow
- Diastolic flow reversal into the descending aorta
28. Aortic regurgitation
Management
• Medical treatment
- Diuretics, digoxin, salt restriction
- Vasodilators
- Endocarditis prophylaxis
• Without surgery, death usually occurs within 4 years of
developing angina and within 2 years after onset of heart
failure.
29. Aortic regurgitation
Surgical therapy
• Severe acute AR requires prompt surgical intervention.
• Chronic severe AR
- Symptomatic patients with normal LV function
- Symptomatic patients with LV dysfunction or dilatation
- Asymptomatic patients with LV dysfunction or dilatation
(EF<50% or end-systolic diameter > 55mm)
• Aortic valve and root replacement- if aortic root diameter is ≥
50mm.
30. Mitral stenosis
Aetiology
• Rheumatic
• Congenital
• Carcinoid, SLE, rheumatoid arthritis, mucopolysaccharidoses.
• Left atrial myxoma, ball-valve thrombus, infective
endocarditis with large vegetation and cor triatriatum.
31. Rheumatic mitral stenosis
• Fusion of the valves, commisures and chordae
• Symptoms usuually occur in the 3rd
or 4th
decade, but mild MS in
the aged is becoming more common.
• 25% of patients have pure mitral stenosis and two-thirds are
female.
• Lutembacher’s syndrome- associated with an atrial septal defect
32. Mitral stenosis
Pathophysiology
• Normal mitral valve area = 4-6cm2
.
• A mitral valve area ≤ 1cm2
equates to severe mitral stenosis.
• Symptoms usually develop when mitral valve area ≤ 2.5cm2
• Symptoms in mild mitral stenosis usually precipitated by
exercise, emotional stress, infection, pregnancy or fast atrial
fibrillation.
33. Mitral stenosis
Natural history
• Long latent period of 20 to 40 years
• Once significant limiting symptoms occur, 10-year survival
rate is 5-15%.
• With severe pulmonary hypertension, mean survival falls to
< 3 years.
• Mortality from untreated mitral stenosis is due to progressive
heart failure (60-70%), systemic embolism (20-30%) and
pulmonary embolism (10%).
35. Mitral stenosis
Physical findings
• Mitral facies
• Tapping apex beat
• Right ventricular heave, loud P2
• Loud first heart sound.
• Opening snap.
• Rumbling, mid-diastolic murmur with presystolic accentuation
in sinus rhythm.
36. Mitral stenosis
Echo evaluation
• Assessment of valve morphology: degree of leaflet thickness,
mobility and calcification and extent of subvalvular fusion.
• Estimation of left atrial size.
• Doppler echo: estimation of mitral valve area, transvalvular
gradient and PA pressure.
40. Mitral stenosis
Medical treatment
• The asymptomatic patient with mild mitral stenosis should be
managed medically. Medical therapy includes:
- Avoidance of unusual physical stress.
- Salt restriction.
- Diuretics if needed.
- Control of heart rate – β-blocker or digoxin.
- Anticoagulation for AF or prior embolic event.
- Annual follow-up.
- Echocardiography if deterioration in clinical condition.
41. Mitral stenosis
Management of symptomatic mitral stenosis
• Patients with symptoms should undergo clinical re-evaluation
with echocardiography.
• NYHA class II symptoms and mild mitral stenosis may be
managed medically.
• NYHA class II symptoms and at least moderate stenosis
(MVA≤1.5cm2
or mean gradient ≥5mmHg) may be considered
for balloon valvuloplasty.
• NYHA class III or IV symptoms and severe mitral stenosis
should be considered for balloon valvuloplasty or surgery.
43. Mitral stenosis
Mitral valve replacement
• Severe mitral stenosis and contraindications to surgical
commisurotomy or balloon valvuloplasty:
- Restenosis following surgical commisurotomy or balloon
valvuloplasty
- Significant mitral regurgitation
- Extensive calcification of the subvalvular apparatus.
• Operative mortality ranges from 3-8% in most centres.
45. Mitral regurgitation
Aetiology
Mitral regurgitation may be caused by abnormalities of the valve leaflets,
chordae tendinae, papillary muscles or mitral annulus:
• Valve leaflets
- myxomatous degeneration
- rheumatic heart disease
- infective endocarditis
• Chordae tendinae
- congenital, infective endocarditis, trauma, rheumatic fever, myxomatous
• Papillary muscles
- myocardial ischaemia, congenital abnormalities, infiltrative disease
• Mitral annulus
- dilatation eg. ischaemic or dilated cardiomyopathy
- calcification due to degeneration, hypertension, diabetes,
chronic renal failure
46. Mitral regurgitation
Clinical features
• Symptoms usually occur with LV decompensation: dyspnoea
and fatigue.
• Physical findings include:
- Pulse: sharp upstroke
- Apex: displaced, hyperdynamic
- Pansystolic murmur
47. Mitral regurgitation
Natural history
• The natural history of chronic MR depends on the volume of
regurgitation, the state of the myocardium and the underlying
cause.
• Preoperative LV end-systolic diameter is a useful predictor of
postoperative survival in chronic MR.
• The preoperative LV end-systolic diameter should be < 45mm
to ensure normal postoperative LV function.
50. Mitral regurgitation
Medical treatment
• Symptomatic patients may benefit from the following drug
therapy whilst awaiting surgery:
• Vasodilator therapy
• Diuretics
• Digoxin / Beta-blockers in presence of atrial fibrillation.
• Endocarditis prophylaxis
51. Mitral regurgitation
Surgical treatment
• Symptoms or left ventricular end systolic diameter ≥45mm.
• Mitral valve repair or replacement.
• Mitral valve repair better preserves LV function and avoids
the need for chronic anticoagulation.
52. Acute mitral regurgitation
Aetiology
Important causes of acute mitral regurgitation include:
• Infective endocarditis
• Ischaemic dysfunction or rupture of papillary
muscle.
• Malfunction of prosthetic valve.
54. Chronic versus Acute MR
Finding Chronic MR Acute MR
Symptoms subtle onset obvious
Appearance normal/mildly severely ill
dyspnoeic
Tachycardia not striking always present
Apex beat displaced not displaced
Systolic thrill common absent
Murmur harsh pansystolic soft or absent early
systolic component
ECG-LVH usually present absent
CXR severe cardiomegaly normal heart size
55. Acute mitral regurgitation
Medical therapy
The following therapies may be beneficial in reducing the
severity of MR
- Vasodilator therapy
- Inotropic therapy
- Intra-aortic balloon counterpulsation
Surgical therapy
• Indicated in patients with acute severe MR and heart
failure.
• Higher mortality rates than for elective chronic MR
56. Mitral valve prolapse
General features
• 2-6% of the general population
• Twice as common in women.
• Due to myxomatous proliferation of the mitral valve.
• Primary condition, or secondary finding in connective tissue
diseases e.g. Marfan’s syndrome.
• Vast majority asymptomatic.
• Palpitations, dizziness, syncope, or chest discomfort.
• Mid-systolic click, late systolic murmur
57. Mitral valve prolapse
Echocardiographic criteria
• M-mode criterion: ≥ 2mm posterior displacement of one or both
leaflets.
• 2-D echo findings: Systolic displacement of one or both leaflets
within the left atrium in the parasternal long-axis view; leaflet
thickening, redundancy, chordal elongation and annular dilatation.
59. Mitral valve prolapse
Natural history
• Benign prognosis in most patients
• Complications may occur in patients with a systolic murmur,
thickened leaflets, an increased LV or LA size, especially in men
> 45 years old
• Complications include progressive mitral regurgitation, infective
endocarditis, cerebral emboli, arrhythmias and rarely sudden death.
60. Mitral valve prolapse
Management
• Asymptomatic patients without MR or arrhythmias have an
excellent prognosis – follow-up every 3-5 years.
• Patients with a long systolic murmur may show progression of
MR and should be reviewed annually.
• Severe MR requires surgery, often mitral valve repair.
61. Tricuspid stenosis
• Almost always rheumatic
• The low cardiac output state causes fatigue; abdominal
discomfort may occur due to hepatomegaly and ascites.
• The diastolic murmur of tricuspid stenosis is augmented by
inspiration.
• Medical management includes salt restriction and diuretics.
• Surgical treatment in patients with a valve area <2.0cm2
and a
mean pressure gradient >5mmHg.
62. Tricuspid regurgitation
• Most common cause is annular dilatation due to RV failure of
any cause
• Symptoms and signs result from a reduced cardiac output,
ascites, painful congestive hepatomegaly and oedema.
• The pansystolic murmur of TR is usually loudest at the left
sternal edge and augmented by deep inspiration.
• Severe functional TR may be treated by annuloplasty or valve
replacement. Severe TR due to intrinsic tricuspid valve disease
requires valve replacement.
66. Pulmonary stenosis
• Most commonly due to congenital malformation
• Survival into adulthood is the rule, infective endocarditis is a
risk and right ventricular failure is the most common cause of
death.
• Carcinoid plaques may lead to constriction of the pulmonary
valve ring.
67. Pulmonary regurgitation
• Most common cause is ring dilatation due to pulmonary
hypertension, or dilatation of the pulmonary artery secondary
to a connective tissue disorder.
• May be present and well-tolerated for many years
• The clinical manifestations of the primary disease tend to
overshadow the pulmonary regurgitation.
68. Pulmonary regurgitation
• Physical examination
– right ventricular heave
– high-pitched, blowing, early diastolic decrescendo murmur
• left sternal edge
• augmented by deep inspiration.
• Pulmonary regurgitation is seldom severe enough to
require specific treatment. Surgery may be required
because of intractable RV failure.
69. Prosthetic valves
Prosthetic valves may be divided into 2 broad categories:
Mechanical valves
• Very good durability.
• Require long-term anticoagulation.
• May cause mild haemolysis.
Bioprosthetic (tissue) valves
• Porcine variety most commonly used.
• Limited durability.
• Anticoagulation for first 3 months only.
72. Prosthetic valves
Mechanical versus tissue valves
• No difference in survival, haemodynamics or in probability of
developing endocarditis, valve thrombosis or systemic
embolism.
• Valve-related failure is much more common with tissue valves.
• Anticoagulant-related bleeding occurs with mechanical valves.
• Elderly patients tend to receive tissue valves.
VHD, although not as common as coronary disease, heart failure or hypertension, is an important and challenging clinical entity. Important changes in patient characteristics and etiologies have occurred over recent years. There has been a continuous decline in rheumatic heart disease, while increased life expectancy accounts for the increase in the incidence of degenerative valvular diseases. During the past 20 years, major advances have occurred in the understanding of natural history, pathophysiology, diagnostic evaluation and the treatment of patients with valvular heart disease.
The incidental finding of a cardiac murmur often raises the suspicion of underlying valvular disease and therefore requires careful evaluation. A heart murmur may be systolic or diastolic, pathological or benign. Many systolic murmurs do not signify cardiac disease, and are related to physiological increases in blood flow velocity. On the other hand, a heart murmur may be an important finding in the diagnosis of undetected, as yet asymptomatic cardiac disease. Diastolic murmurs almost always represent pathological conditions and require further cardiac evaluation, as do most continuous murmurs.
An ECG and chest X-ray are readily available investigations, but they provide limited information about the significance and aetiology of a heart murmur.
Echocardiography is the most useful investigation to assess the significance of a heart murmur and has the advantage of being a non-invasive test. 2-D echocardiography may indicate abnormal valvular motion and morphology and assesses left ventricular size and function. Doppler echocardiography identifies increased velocity of flow across stenotic valves from which the severity of stenosis may be determined. The presence of an abnormal regurgitant jet on Doppler colour flow imaging indicates valvular regurgitation and provides semiquantitative information about its severity.
Echocardiography is the most useful investigation to assess the significance of a heart murmur and has the advantage of being a non-invasive test. 2-D echocardiography may indicate abnormal valvular motion and morphology and assesses left ventricular size and function. Doppler echocardiography identifies increased velocity of flow across stenotic valves from which the severity of stenosis may be determined. The presence of an abnormal regurgitant jet on Doppler colour flow imaging indicates valvular regurgitation and provides semiquantitative information about its severity.
Cardiac symptoms in the setting of valvular heart disease are predominantly exertional breathlessness, and perhaps breathlessness at rest in the advanced stages of disease.
Other symptoms may include angina, dizziness and syncope (usually in the setting of stenotic lesions).
In day-to-day clinical practice, left sided valve lesions account for the vast majority of cardiological practice. Tricuspid valve disease is most commonly seen in association with left sided (particularly mitral) valve disease. Pulmonary valve disease is most commonly secondary to pulmonary hypertension, or in association with other congenital heart defects.
A normal aortic valve is formed of 3 cusps. Congenital malformations may be tricuspid, bicuspid or more rarely unicuspid or even quadricuspid.
Unicuspid valves are often fatal in childhood. Bicuspid valves are not usually stenotic at birth and the changes causing stenosis resemble those occurring in acquired degenerative disease, but many decades earlier. The congenitally malformed tricuspid aortic valve has cusps of unequal size and some commissural fusion.
Acquired degenerative aortic valve disease is the most common cause of aortic stenosis in the elderly. The cusps are immobilised by deposits of calcium resulting from years of normal mechanical stress on the valve. Hypertension, diabetes and hypercholesterolaemia are risk factors for this lesion.
Rheumatic aortic stenosis is decreasing in frequency because of a decline in rheumatic fever. Stenosis results from fusion of the cusps producing an orifice that is reduced to a small round or triangular opening, often leading to both stenosis and regurgitation.
Bicuspid and quadricuspid valves tend to suffer from degenerative disease in a similar way to tricuspid valves, but this often occurs many decades earlier, as non-tricuspid valves tend to be more prone to shear stress and endothelial disruption, triggering sclerosis and calcification.
This process tends to happen over many years, LV systolic dysfunction occuring very late in the process.
The cardinal symptoms of aortic stenosis are angina, syncope and dyspnoea. Angina occurs in approximately two-thirds of patients with critical aortic stenosis, of whom about 50% have associated coronary artery disease. Syncope is usually due to reduced cerebral perfusion during exertion, in the face of vasodilatation and a fixed cardiac output. However, the possibility of arrhythmias should be borne in mind, particularly when syncope occurs at rest. Sudden death rarely occurs without preceding symptoms.
The arterial pulse characteristically rises slowly, is low in amplitude and sustained. In the advanced stage, systolic and pulse pressure are both reduced. The apex beat is sustained and a systolic thrill is often palpable over the aortic area. Auscultatory findings include an ejection systolic, crescendo-decrescendo murmur, loudest over the aortic area and radiating to the neck and left sternal edge. The second heart sounds soft or inaudible. The ECG may demonstrate left ventricular hypertrophy or AV node conduction defects.
There are two main methods to grade the severity of aortic stenosis, both usually measured by echocardiography – the aortic valve gradient, and the aortic valve area.
The aortic valve area must be reduced to one quarter of its normal size before significant changes in the circulation occur. The normal valve area is
3-4cm2; mild stenosis = valve area of 1.5-3cm2; moderate stenosis = valve area of 1.0-1.5cm2; severe stenosis = valve area of &lt;1.0cm2.
When stenosis is severe and left ventricular function is normal, the peak aortic valve gradient derived by echocardiography is usually &gt;60mmHg.
Initially, there is a prolonged latent period during which the patient remains asymptomatic, despite gradually increasing aortic valve stenosis. In asymptomatic patients with an AV gradient &gt;60mmHg, 50-60% will develop symptoms within 2-3 years. After the onset of symptoms, average survival is &lt;2-3 years.
Conservative medical therapy should be offered to those with mild to moderate aortic stenosis and to asymptomatic patients with severe aortic stenosis as follows:
-Advise to report symptoms
-Avoid vigorous exercise
-Antiobiotic prophylaxis for endocarditis
-Regular follow-up ± echocardiography
Aortic valve replacement should be offered to the following patients:
Symptomatic patients with severe aortic stenosis
Patients with severe aortic stenosis undergoing CABG surgery
Patients with moderate aortic stenosis undergoing CABG surgery
Asymptomatic patients with severe aortic stenosis and left ventricular dysfunction
Balloon valvuloplasty can play a temporary role in the management of symptomatic patients who are not initially considered suitable for aortic valve replacement:
Palliation for patients with serious comorbid conditions
A bridge to surgery in haemodynamically unstable patients
In the absence of LV dysfunction, operative risk is 2-5%. Risk factors for higher mortality are NYHA class, LV dysfunction, age, concomitant coronary artery disease, and aortic regurgitation. Successful valve replacement usually results in reduced LV volumes, improved LV performance and regression of LV hypertrophy.
TAVI is a novel therapy used as an alternative to standard surgical AVR. Performed on a beating heart without the need for a sternotomy or cardiopulmonary bypass. Currently reserved for pts who have been considered by a MDT who consider the risk/benefit ratio of open heart surgery and TAVI to favour TAVI. In general, TAVI should be perfomed for symptomatic severe degenerative aortic stenosis.
Aortic regurgitation is either due to primary disease of the aortic valve leaflets or wall of the aortic root or both.
The causes of primary aortic valve disease include the following:
-Congenital eg. bicuspid aortic valve
-Acquired:rheumatic valve disease, infective endocarditis, trauma and connective tissue disease.
The causes of primary aortic root disease causing dilatation of the ascending aorta and subsequent aortic regurgitation include the following:
-Degenerative, cystic medial necrosis (eg. Marfan’s), aortic dissection, syphilis, connective tissue disease and hypertension.
In chronic severe AR, the left ventricle gradually enlarges while the patient remains asymptomatic. Symptoms usually develop after cardiomegaly and LV dysfunction have occurred. Dyspnoea is the principal complaint. Syncope is rare and angina is less frequent than in aortic stenosis.
In acute severe AR, LV decompensation occurs readily with clinical manifestations of cardiovascular collapse including fatigue , severe dyspnoea and hypotension.
Rather than LV outflow obstruction and pressure overload, aortic regurgitation places a much higher volume load on the left ventricle resulting in LV dilatation and eventually systolic impairment.
In addition to the physical findings listed above, a number of other clinical signs attributable to significant aortic regurgitation include:
De Musset’s sign:Bobbing of the head with each heartbeat.
Corrigan’s sign:Prominent carotid artery pulsations.
Traube’s sign:Booming systolic and diastolic sounds heard over the femoral artery.
Muller’s sign:Systolic pulsations of the uvula.
Duroziez’s sign:Systolic murmur over the femoral artery when compressed proximally and diastolic murmur when compressed distally.
Quincke’s sign:Capillary pulsations detected by transmitting light through the patient’s fingertips.
Austin Flint murmur:Rumbling mid-diastolic murmur caused by mitral valve narrowing due to regurgitant blood flow directed at the anterior mitral leaflet and associated raised LV diastolic pressure.
Assessment of severity is based upon an combination of clinical and echocardiographic signs. As well as the direct appearance of the aortic regurgitation jet, echocardiography can also assess for indirect haemodynamic effects. In the case of severe AR, reversal of normal diastolic flow may be seen in the ascending aorta.
Asymptomatic patients with mild or moderate AR do not require medical therapy, but should be followed up every 12-24 months with repeat echocardiography. Digoxin may be given to patients with severe AR and LV dilatation. Although patients with severe AR and LV dysfunction require surgery, they respond at least temporarily to digoxin, salt restriction, diuretics and vasodilators.
Since early demise due to left ventricular failure is frequent in patients with severe acute aortic regurgitation despite intensive medical management, prompt surgical intervention is indicated.
Surgical intervention is usually deferred in patients with severe chronic AR who are asymptomatic with a good exercise tolerance and normal LV function. However, the onset of symptoms or left ventricular dysfunction and dilatation merits operative correction. Indications for aortic valve replacement in pure, severe, chronic aortic regurgitation include:
-Symptomatic patients with normal left ventricular systolic function
-Symptomatic patients with left ventricular dysfunction or dilatation
-Asymptomatic patients with left ventricular dysfunction or dilatation (EF&lt;50% or end-systolic diameter &gt; 55mm)
In general, aortic valve and root replacement are indicated in patients with disease of the proximal aorta and aortic regurgitation of any severity when the aortic root diameter is ≥ 50mm by echocardiography.
Rheumatic fever is the predominant cause of mitral stenosis. Rarely, mitral stenosis is congenital in aetiology and this is observed almost exclusively in infants and young children. Other possible causes include carcinoid, SLE, rheumatoid arthritis and mucopolysaccharidoses.
Other causes of left atrial outflow obstruction may simulate mitral stenosis eg. left atrial myxoma, ball-valve thrombus, infective endocarditis with large vegetation and cor triatriatum (congenital membrane in the left atrium).
Rheumatic mitral stenosis is due to four forms of fusion: commissural (30%), cuspal (15%), chordal (10%) or combined (45%). The stenotic mitral valve is typically funnel-shaped and the orifice is frequently shaped like a fish mouth. Symptoms commence most commonly in the third or fourth decade, although mild MS in the aged is becoming a more common finding. 25% of patients with rheumatic mitral valve disease have pure mitral stenosis and two-thirds are female. The combination of rheumatic mitral stenosis and an atrial septal defect is known as Lutembacher’s syndrome.
The normal adult cross-sectional area of the mitral valve is 4-6 cm2. Narrowing of the valve area to 2.5cm2 must occur before the development of symptoms. A mitral valve area of &gt;1.5cm2 usually does not produce symptoms at rest. However, an increase in transmitral flow or a decrease in the diastolic filling period may raise the left atrial pressure and thereby lead to the development of symptoms. Thus, the first symptoms of dyspnoea in patients with mild mitral stenosis are usually precipitated by exercise, emotional stress, infection, pregnancy or fast atrial fibrillation. In the presence of severe mitral stenosis (mitral valve area ≤ 1 cm2), left atrial pressure becomes chronically elevated leading to raised pulmonary venous and capillary pressures and the development of dyspnoea. Pulmonary hypertension in patients with mitral stenosis results from (i) passive backward transmission of the raised left atrial pressure; (ii) pulmonary arteriolar constriction triggered by left atrial and pulmonary venous hypertension; (iii) organic obliterative changes in the pulmonary vascular bed as a complication of longstanding and severe mitral stenosis.
In developed countries, there is a long latent period of 20 to 40 years from the occurrence of rheumatic fever to the onset of symptoms. Once symptoms develop, there is another period of almost a decade before symptoms become disabling. Once significant limiting symptoms occur there is a 10-year survival rate of 5-15% and when there is severe pulmonary hypertension, mean survival drops to &lt; 3 years. Mortality of untreated patients with mitral stenosis is caused by progressive heart failure in 60-70%, systemic embolism in 20-30% and pulmonary embolism in 10% of patients.
The principal symptom is dyspnoea mainly due to reduced compliance of the lungs. Haemoptysis may also occur. Approximately 15% of patients experience angina which may be due to either coincidental coronary artery disease, right ventricular hypertension or coronary embolisation. The tendency for embolisation correlates inversely with cardiac output and directly with the patient’s age and size of the left atrial appendage. 80% of patients with systemic emboli are in atrial fibrillation.
Characteristic physical findings include:
-Mitral facies – pinkish-purple patches on the cheeks, present in patients with severe mitral stenosis, low cardiac output and systemic vasoconstriction.
-Right ventricular heave and loud pulmonary component of the second heart sound - indicate the presence of pulmonary hypertension.
-Tapping apex beat – palpable first heart sound indicating a pliable anterior mitral leaflet.
-Opening snap - due to a sudden tensing of the valve leaflets at maximum opening of the mitral valve.
-Low-pitched, rumbling mid-diastolic murmur with presystolic accentuation in sinus rhythm, best heard with the bell of the stethoscope at the apex with the patient’s breath held in expiration.
Echocardiography is the diagnostic tool of choice in the evaluation of a patient with mitral stenosis. 2-D imaging allows the assessment of mitral valve morphology including leaflet mobility, leaflet thickness, leaflet calcification, subvalvular fusion and appearance of the commisures. Left atrial size can also be measured. Doppler echocardiography allows the estimation of mitral valve area, mean transmitral pressure gradient and pulmonary artery pressure.
The asymptomatic patient with mild mitral stenosis (mitral valve area &gt; 1.5cm2 and mean gradient &lt;5mmHg) needs no further investigation as these patients usually remain stable for many years. Annual review is recommended and echocardiography should be repeated if there is a deterioration in symptoms or clinical signs.
Medical therapy includes the following:
- Avoid unusual physical stress
- Salt restriction
- Diuretics
- Control of heart rate
- Anticoagulation: patients with paroxysmal or chronic atrial fibrillation, or a prior embolic event.
Antibiotic prophylaxis
The asymptomatic patient with more severe mitral stensosis and pliable, noncalcified valves with little or no subvalvular fusion and no calcification in the commissures should be considered for balloon mitral valvuloplasty.
Patients who develop symptoms should undergo clinical re-evaluation with CXR, ECG and echocardiography. In general, patients with NYHA class II symptoms and mild mitral stenosis may be managed medically. Patients with NYHA class II symptoms and at least moderate stenosis (MVA≤1.5cm2 or mean gradient ≥5mmHg) may be considered for balloon mitral valvuloplasty. Patients with NYHA class III or IV symptoms and severe mitral stenosis have a poor prognosis if left untreated and intervention with balloon valvuloplasty or surgery should be considered.
Balloon mitral valvuloplasty emerged in the 1980s and has become an acceptable alternative to surgery in selected patients. The technique involves passing a balloon flotation catheter across the interatrial septum, after trans-septal puncture, and dilating the balloon within the mitral valve orifice. The results of the procedure are highly dependent on the experience of the operator. In experienced hands, the immediate results of balloon mitral valvuloplasty are similar to those of surgical mitral commisurotomy. The valve area usually doubles with a 50% to 60% reduction in the transmitral gradient; 80-95% of patients have a successful procedure defined as a mitral valve area &gt;1.5cm2 and a decrease in left atrial pressure to ≤18mmHg in the absence of complications.
However, there is a 4-5% complication rate including severe mitral regurgitation, residual atrial septal defect, myocardial perforation, emboli, myocardial infarction and death. The overall event-free survival rate is 50% to 65% over 3-7 years. The underlying mitral valve morphology is the most important factor in determining outcome. The procedure is usually more successful and with a better outcome in patients with noncalcified pliable valves and no commissural calcification. Relative contraindications include the presence of a left atrial thrombus and significant mitral regurgitation. In centres with skilled, experienced operators, balloon mitral valvuloplasty should be considered for symptomatic patients with moderate to severe mitral stenosis and favourable valve morphology in the absence of significant mitral regurgitation or a left atrial thrombus.
Mitral valve replacement is an accepted surgical procedure for patients with severe mitral stenosis who are not candidates for open or closed surgical commisurotomy or balloon mitral valvuloplasty. Such patients include those with both significant mitral stenosis and regurgitation, or those with extensive calcification of the subvalvular apparatus. The operative mortality ranges from 3-8% in most centres. Postponement of surgery until the patient reaches NYHA class IV symptoms should be avoided because operative mortality is high and long term outcome suboptimal. However, surgery should not be denied because the outlook without surgical intervention is grave.
The mitral valve apparatus involves the mitral leaflets, the chordae tendinae, the papillary muscles and the mitral annulus. Mitral regurgitation may therefore be caused by abnormalities of any of these structures:
Abnormalities of the valve leaflets:- myxomatous degeneration causing mitral valve prolapse
- shortening, rigidity, deformity and retraction by rheumatic heart disease
- vegetations/infective endocarditis
Abnormalities of the chordae tendinae:- congenital, infective endocarditis, trauma, rheumatic fever, mitral valve prolapse
Abnormalities of the papillary muscles:- myocardial ischaemia, congenital abnormalities, infiltrative disease
Abnormalities of the mitral annulus:- dilatation eg. ischaemic cardiomyopathy
- calcification eg. degenerative, hypertension, aortic stenosis, diabetes, chronic renal failure
Symptoms
Symptoms usually do not develop in patients with chronic mitral regurgitation until the left ventricle fails. The predominant symptoms are dyspnoea, fatigue and weakness.
Examination
- Pulse: sharp upstroke
- Apex: displaced, hyperdynamic
- Heart sounds: soft S1, pansystolic murmur loudest at the apex, radiating to the axilla and accentuated by expiration, wide splitting of S2, S3 present.
Natural history
The natural history of chronic mitral regurgitation depends on a combination of the volume of regurgitation, the state of the myocardium and the cause of the underlying disorder. Nevertheless, preoperative left ventricular end-systolic diameter is a useful predictor of postoperative survival in patients with chronic mitral regurgitation. The end-systolic diameter should be &lt; 45mm before surgery to ensure normal postoperative left ventricular function.
For the asymptomatic patient with chronic mitral regurgitation, there is no generally accepted medical therapy. Symptomatic patients may benefit from the following drug therapy whilst awaiting surgery:
Vasodilator therapy
Diuretics
Digoxin / Beta-blockers in presence of atrial fibrillation.
Endocarditis prophylaxis
The need for surgery in patients with chronic severe mitral regurgitation is dependent on symptomatic status and left ventricular function. Surgery is indicated in the presence of symptoms or left ventricular end systolic diameter ≥45mm. The surgical procedure consists of either mitral valve repair or replacement. Mitral valve repair has the advantage of better preserving left ventricular function and avoiding the need for chronic anticoagulation. However, the procedure is technically more demanding and often not possible to perform in severely deformed valves.
Mortality rates for mitral valve surgery approximate to 1-4% in predominant mitral stenosis and 2-7% in predominant mitral regurgitation.
The causes of acute mitral regurgitation are diverse and represent acute manifestations of disease processes that may under other circumstances cause chronic mitral regurgitation. Important causes include:
- Infective endocarditis causing disruption of valve leaflets or chordal rupture.
- Ischaemic dysfunction or rupture of papillary muscle.
- Malfunction of prosthetic valve.
As summarized in the table above, both the clinical features and haemodynamic findings between acute and chronic severe mitral regurgitation may differ widely. Many of the haemodynamic consequences derive from the difference in left atrial compliance in acute versus severe mitral regurgitation. Patients with acute mitral regurgitation usually have a normal-sized left atrium with normal or reduced atrial compliance leading to the rapid development of pulmonary oedema.
Medical therapy
Depending on haemodynamic status, the following therapeutic options may be beneficial in reducing the severity of mitral regurgitation:
- Vasodilator therapy
- Inotropic therapy
- Intra-aortic balloon counterpulsation
Surgical therapy
Surgery is usually indicated in patients with acute severe mitral regurgitation and heart failure. Mortality rates are usually higher than for elective chronic mitral regurgitation, but unless such patients are treated aggressively, a fatal outcome is almost certain.
This is the most common form of valvular heart disease, occurring in 2-6% of the population and is twice as common in women. It is due to myxomatous proliferation of the mitral valve causing an increased surface area of the valve, leading to impaired coaptation of the leaflet edges and resultant mitral regurgitation. The severity of mitral regurgitation depends on the extent of prolapse.
It usually occurs as a primary condition unassociated with other disease, but can be a secondary finding in certain connective tissue diseases. It is found in approximately 90% of patients with Marfan’s syndrome.
The vast majority of patients with MVP are asymptomatic. Patients may complain of palpitations, dizziness, syncope, chest discomfort, but whether these symptoms are truly attributable to the MVP is often unclear.
The principal cardiac auscultatory finding is the midsystolic click resulting from sudden tensing of the mitral valve apparatus as the leaflets prolapse into the left atrium during systole. In the presence of regurgitation, the midsystolic click is followed by a late systolic murmur.
Echocardiography is the most useful investigation for defining mitral valve prolapse:
- M-mode criterion: 2mm posterior displacement of one or both leaflets
- 2-D echo findings may include: Systolic displacement of one or both mitral leaflets within the left atrium in the parasternal long-axis view; leaflet thickening, redundancy, chordal elongation and annular dilatation.
The diagnosis of mitral valve prolapse is even more certain when leaflet thickness is &gt;5mm.
Echocardiography is useful in the risk stratification of patients with mitral valve prolapse
Natural history
In most patients, mitral valve prolapse is associated with a benign prognosis.
Complications may occur in patients with a systolic murmur, thickened leaflets an increased LV or LA size, especially in men &gt; 45 years old:
Complications include progressive mitral regurgitation, infective endocarditis, cerebral emboli, arrhythmias and rarely sudden death.
Asymptomatic patients without mitral regurgitation or arrhythmias have an excellent prognosis and may be followed-up every 3-5 years.
In patients with a typical systolic murmur indicating mitral regurgitation, endocarditis prophylaxis should be given. Note – recent NICE guidelines.
Patients with a long systolic murmur may show progression of mitral regurgitation and should be reviewed annually. Severe mitral regurgitation requires surgery, often mitral valve repair.
Antiplatelet / anticoagulant therapy should be recommended to patients with previous embolic events.
Tricuspid stenosis, although very uncommon, is always rheumatic in origin and when present accompanies mitral valve involvement. The majority of cases of rheumatic tricuspid valve disease present with tricuspid regurgitation or a combination of stenosis and regurgitation. The anatomical changes resemble those of mitral stenosis. The physiological principles are also similar to those of mitral stenosis but reflect changes to the systemic venous circulation rather than the pulmonary venous system. The low cardiac output characteristic of tricuspid stenosis, causes fatigue and abdominal discomfort may occur due to hepatomegaly and ascites. The diastolic murmur of tricuspid stenosis, unlike mitral stenosis is augmented by inspiration.
Medical management includes salt restriction and diuretic therapy. Surgical treatment should be carried out in patients with a valve area &lt;2.0cm2 and a mean pressure gradient &gt;5mmHg. A porcine bioprosthesis is the preferred choice of valve because of the high risk of thrombosis with mechanical valves in this position.
Other causes of obstruction to right atrial emptying are rare and include congenital tricuspid atresia, right atrial tumours and the carcinoid syndrome.
Aetiology
The most common cause of tricuspid regurgitation is annular dilatation due to right ventricular failure of any cause eg. mitral valve disease, right ventricular infarction, congenital heart disease, primary pulmonary hypertension and rarely cor pulmonale.
Causes of TR due to intrinsic valve involvement include Ebstein’s anomaly, atrioventricular canal defects, rheumatic heart disease, carcinoid syndrome, myxomatous degeneration and infective endocarditis.
Clinical features
TR is generally well tolerated in the absence of pulmonary hypertension. However, in the presence of pulmonary hypertension, cardiac output declines and right-sided heart failure may worsen. Therefore, the symptoms and signs of TR result from a reduced cardiac output, ascites, painful congestive hepatomegaly and oedema. The pansystolic murmur of tricuspid regurgitation is usually loudest at the left sternal edge and augmented by deep inspiration.
Management
TR in the absence of pulmonary hypertension usually does not require surgical treatment.
Patients with severe TR and rheumatic heart disease require ring annuloplasty. The management of severe functional TR is controversial and may be treated by annuloplasty or valve replacement. Severe TR due to intrinsic tricuspid valve disease eg. Ebstein’s anomaly or carcinoid usually requires valve replacement.
Pulmonary stenosis is most commonly due to congenital malformation and usually an isolated anomaly. Survival into adulthood is the rule, infective endocarditis is a risk and right ventricular failure is the most common cause of death.
Rheumatic involvement of the pulmonary valve is very uncommon and rarely leads to serious deformity. Carcinoid plaques may lead to constriction of the pulmonary valve ring.
Aetiology
Most common cause is dilatation of the valve ring secondary to pulmonary hypertension, or to dilatation of the pulmonary artery secondary to a connective tissue disorder. The second most common cause is infective endocarditis. Pulmonary regurgitation may also result from congenital malformations, trauma, carcinoid syndrome or iatrogenic causes.
Clinical features
Isolated pulmonary regurgitation may be tolerated for many years unless it is complicated by pulmonary hypertension. In most patients, the clinical manifestations of the primary disease overshadow the pulmonary regurgitation. Physical examination reveals a hyperdynamic right ventricle producing a right ventricular heave in the left parasternal area. The murmur of pulmonary regurgitation is a high-pitched, blowing, early diastolic decrescendo murmur heard best over the left sternal edge and augmented by deep inspiration.
Management
Pulmonary regurgitation is seldom severe enough to require specific treatment. Surgery is required only occasionally because of intractable right ventricular failure, preferably with a porcine bioprothesis.
