Aortic stenosis

Three types:

1. Valvular (Involving valve cusps. It is the most common type.)
2. Subvalvular (Narrowing of outflow tract of left ventricle. Membranous diaphragm or fibrous ridge just below the aortic valve.)
3. Rarely, supravalvular  (Constriction at the first part of aorta. Narrowing in ascending aorta or fibrous diaphragm just above aortic valve). It may be associated with characteristic face such as broad forehead, widely set eyes and pointed chin, mental retardation and hypercalcaemia called William syndrome.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 186; Short Cases in Clinical Medicine, ABM Abdullah, 5th Edition Page: 83

It is a degenerative condition in which there is thickening and/or calcification of leaflets of aortic valve.

• It affects older people aged above 65 years.
• It does not produce any significant obstruction to the outflow of blood.

Note:

Risk of aortic sclerosis:

• There are some risk factor like hyperlipidemia, diabetes mellitus, smoking, hypertension are prone to develop aortic calcification.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 186; Short and Long Cases in Clinical Medicine, HN Sarker Page: 46

It is a crescendo-decrescendo murmur starting after the first heart sound, peak in mid systole and ends before the second heart sound.

See details of murmur at Examination of cardiovascular system

* Short and Long Cases in Clinical Medicine, HN Sarker Page: 46

Heyde’s syndrome is the association between aortic stenosis and occult gastrointestinal bleeding usually from colonic angiodysplasia.

* Short and Long Cases in Clinical Medicine, HN Sarker Page: 47

As follows:

• Chronic rheumatic heart disease
• Bicuspid aortic valve (common in male)
• Degenerative calcification in old age
• Congenital (in early age).

Causes of aortic stenosis according to age:¹

1. Infants, children, adolescents
   • Congenital aortic stenosis
   • Congenital subvalvular aortic stenosis
   • Congenital supravalvular aortic stenosis
2. Young adults to middle-aged
   • Calcification and fibrosis of congenitally bicuspid aortic valve
   • Rheumatic aortic stenosis
3. Middle-aged to elderly
   • Senile degenerative aortic stenosis
   • Calcification of bicuspid valve
   • Rheumatic aortic stenosis

* Long Cases in Clinical Medicine, ABM Abdullah Page: 185; Short and Long Cases in Clinical Medicine, HN Sarker Page: 46; ¹Davidson’s Principles and Practice of Medicine, 22nd Edition Page: 620

Anacrotic or plateau pulse – low volume slow rising pulse, may be –

• small-volume pulse (pulsus parvus) or
• late peaking (pulsus tardus ).

Read more about pulse at Examination of cardiovascular system

* Short Cases in Clinical Medicine, ABM Abdullah, 5th Edition Page: 82; Short and Long Cases in Clinical Medicine, HN Sarker Page: 46

• There is left ventricular hypertrophy, so there is more oxygen demand.
• Also, there is reduced coronary flow due to less cardiac output (limitation of duration of diastole).

* Long Cases in Clinical Medicine, ABM Abdullah Page: 187

Iron deficiency anemia may occur in aortic stenosis particularly in elderly patient due to occult gastrointestinal bleeding usually from colonic angiodysplastic lesions (Heyde’s syndrome).

* Short and Long Cases in Clinical Medicine, HN Sarker Page: 47

Symptoms

• Mild or moderate stenosis: usually asymptomatic
• Exertional dyspnoea
• Angina
• Exertional syncope (which may be due to inadequate cardiac output or reflex vasodilatation after exercise or arrhythmia)
• Sudden death (probably due to ventricular fibrillation)
• Episodes of acute pulmonary oedema

Signs

• Ejection systolic murmur
• Slow-rising carotid pulse
• Thrusting apex beat (LV pressure overload)
• Narrow pulse pressure
• Signs of pulmonary venous congestion (e.g. crepitations)

Note:

Aortic stenosis is commonly picked up in asymptomatic patients at routine clinical examination but the three cardinal symptoms are

1. angina,
2. breathlessness and
3. syncope

* Davidson’s Principles and Practice of Medicine, 22nd Edition Page: 620; Long Cases in Clinical Medicine, ABM Abdullah Page: 187

• Pulse: 76/min, low volume and slow raising, normal in rhythm.
• JVP: Normal.
• BP: 90/80 mmHg (low systolic, normal diastolic and narrow pulse pressure)

On inspection:

• Visible cardiac impulse in mitral area (or nothing significant).

On palpation:

• Apex beat: In left … intercostal space, … cm from midline, heaving in nature.
• Systolic thrill: Present in aortic area, radiates to the right side of neck.

On auscultation:

• First heart sound: Normal in all the areas.
• Second heart sound: A2 is soft in all areas and P2 is normal.
• There is a harsh ejection systolic murmur in aortic area, which radiates to right side of neck.
• May be reversed splitting of second heart sound, and fourth heart sound may be present.

* Short Cases in Clinical Medicine, ABM Abdullah, 5th Edition Page: 82

Signs of severe AS are:

• Pulse is feeble or absent. Slow-rising carotid pulse may be present
• Narrow pulse pressure
• Thrusting apex beat (LV pressure overload)
• Systolic aortic thrill
• Soft or absent aortic component of the second heart sound (A2)
• Reversed splitting of second heart sound
• Presence of fourth heart sound
• Late systolic peaking of a harsh, loud, long murmur (soft and short ESM with early peaking suggest mild stenosis)
• Signs of pulmonary venous congestion (e.g. crepitations)
• Presence of heart failure or LVF (late sign)

Note:

• A harsh ejection systolic murmur radiates to the neck, with a soft second heart sound, particularly in those with calcific valves. The murmur is often likened to a saw cutting wood and may (especially in older patients) have a musical quality like the ‘mew’ of a seagull.
• Normal area of aortic valve is 1.5 to 2 cm². It is severe, if the area is < 1 cm² or valve mean pressure gradient is > 50 mm Hg.
• Critical aortic stenosis: If the valve area is < 0.7 cm² or valve pressure gradient is > 70 mm Hg.

* Davidson’s Principles and Practice of Medicine, 22nd Edition Page: 620; Long Cases in Clinical Medicine, ABM Abdullah Page: 187; Short and Long Cases in Clinical Medicine, HN Sarker Page: 46

The murmur of aortic stenosis is heard throughout the precordium, but is usually loudest in the aortic area.

* Short and Long Cases in Clinical Medicine, HN Sarker Page: 46

Duration of murmur is associated with severity. Prolongation of murmur indicates severity. Loudness of murmur may be associated with mild stenosis.

* Short and Long Cases in Clinical Medicine, HN Sarker Page: 46

ECG

• Left ventricular hypertrophy (usually)
• Left bundle branch block

Chest X-ray

• May be normal; sometimes enlarged LV and dilated ascending aorta on PA view, calcified valve on lateral view

Echo

• Calcified valve with restricted opening, hypertrophied LV
• Doppler
• Measurement of severity of stenosis
• Detection of associated aortic regurgitation

Cardiac catheterisation

• Mainly to identify associated coronary artery disease
• May be used to measure gradient between LV and aorta

Figure: Aortic stenosis. Pressure traces show the systolic gradient between LV and aorta. The ‘diamond-shaped’ murmur is heard best with the diaphragm in the aortic outflow and also at the apex. An ejection click (EC) may be present in young patients with a bicuspid aortic valve but not in older patients with calcified valves. Aortic stenosis may lead to left ventricular hypertrophy with a fourth sound at the apex and post-stenotic dilatation of the aortic arch.

* Davidson’s Principles and Practice of Medicine, 22nd Edition Page: 621

The X-ray findings of aortic stenosis are as follows:

• Poststenotic dilatation of proximal ascending aorta
• Calcification of arotic valve
• Cardiomegaly (in late stages if failure develops)
• Pulmonary congestion
• Prominent pulmonary arteries (pulmonary hypertension)
• Rib notching (sign of coarctation of the aorta, frequently seen with bicuspid aortic valve)

* Short and Long Cases in Clinical Medicine, HN Sarker Page: 47

The ECG findings of aortic stenosis are:

• Left ventricular hypertrophy with strain pattern
• Left bundle branch block (LBBB)
• Left axis deviation

* Short and Long Cases in Clinical Medicine, HN Sarker Page: 47

The echocardiographic findings of aortic stenosis are

• Left ventricular size, wall thickness and function
• Aortic valve area
• Aortic valve calcification
• Bicuspid aortic valve

* Short and Long Cases in Clinical Medicine, HN Sarker Page: 47

The indications of coronary angiography in aortic stenosis are as follows

• To exclude coronary artery disease as a cause for symptoms
• All patients undergoing valve replacement should have coronary angiography to exclude significant coronary stenoses that would require bypass grafting at the time of valve replacement.

* Short and Long Cases in Clinical Medicine, HN Sarker Page: 67

• ETT (endotracheal tube) is contraindicated in symptomatic patient with aortic stenosis as it may be fatal.
• However, it may be done in asymptomatic cases with high grade aortic stenosis. May be helpful in deciding the role of surgery.

* Short and Long Cases in Clinical Medicine, HN Sarker Page: 47; Long Cases in Clinical Medicine, ABM Abdullah Page: 186

Because:

• In the history, there is exertional dyspnea, chest pain and syncopal attack.
• On examination, there is systolic thrill in aortic area, soft aortic component of second sound (A₂)and ejection systolic murmur in aortic area that radiates to the carotid.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 184

As follows:

• Pulmonary stenosis
• Hypertrophic cardiomyopathy (HCM).

* Long Cases in Clinical Medicine, ABM Abdullah Page: 185

In pulmonary stenosis, findings are:

• Systolic thrill in pulmonary area.
• Left parasternal lift and epigastric pulsation may be present (due to RVH).
• P2 is soft, A2  is normal (wide splitting of the second heart sound may be present).
• Ejection systolic murmur in pulmonary area, which radiates to the left side of neck (murmur is more on inspiration).
• Apex is normal (not heaving as in AS).

* Long Cases in Clinical Medicine, ABM Abdullah Page: 185

In HCM, the findings are:

• Pulse is jerky.
• Prominent “a”  wave in JVP.
• Double impulse at the apex (palpable 4th heart sound due to left atrial hypertrophy).
• Systolic thrill in left lower parasternal area.
• Associated pansystolic murmur due to MR.
• Family history of HCM may be present or there may be history of sudden death in family.

Note:

In HCM, echocardiography is very helpful for diagnosis. ECG shows LVH and bizarre abnormalities like pseudoinfarction pattern, deep T inversion.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 185

The severity of aortic stenosis can be classified as:

1. Using aortic valve area (normal aortic valve area is 3-4 cm²) (the ACC/AHA guidelines)
   • Mild – Valve area > 1.5 cm²
   • Moderate – Valve area 1.5–1.0 cm²
   • Severe – Valve area < 1.0 cm²
2. Using pressure guideline
   • Severe aortic stenosis is defined as a mean gradient > 50mm Hg

* Short and Long Cases in Clinical Medicine, HN Sarker Page: 46

Angiodysplasia of the colon (Heydis syndrome).

* Long Cases in Clinical Medicine, ABM Abdullah Page: 188

Treatment of aortic stenosis includes

1. Asymptotic patient
   • Prophylaxis for infective endocarditis
   • Follow-up regularly
   • Advise to report symptoms of angina, palpitation, syncope, and breathlessness
   • Aortic valve replacement
2. Symptomatic patient
   • Aortic valve replacement

* Short and Long Cases in Clinical Medicine, HN Sarker Page: 47

As follows:

• All symptomatic patient (such as syncope)
• If mean systolic pressure gradient is > 50 mm Hg (left ventricular systolic pressure > aorta) (left ventricular systolic dysfunction)
• If the valve area is < 0.7 cm²  (Normal: 2.5 to 3 cm²)
• Asymptomatic patient undergoing surgery for coronary disease, other valve, LV dysfunction, progressive decline in LVEF, marked LVH
• Abnormal BP in response to exercise (on supervised exercise tolerance test)
• Ventricular tachycardia

* Long Cases in Clinical Medicine, ABM Abdullah Page: 188

Usually biological or tissue valve is preferred than mechanical one, as biological valve does not require anticoagulation. In younger age, mechanical valve is preferred, but anticoagulant should be given.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 188

• Sudden death predominantly occurs in symptomatic patients
• If the aortic valve is not replaced, then the onset of angina, syncope, and dyspnoea has been shown to correlate with an average time to death of 5, 3 and 2 years, respectively.

* Short and Long Cases in Clinical Medicine, HN Sarker Page: 47

The complications of aortic stenosis are as follows

• Left ventricular failure
• Infective endocarditis
• Sudden death (due to ventricular fibrillation particularly in symptomatic aortic stenosis)
• Arrhyhmias (AF, ventricular tachycardia)
• Heart block (calcification of the conduction system)
• Systemic embolism (disintegration of aortic valve apparatus)

* Short and Long Cases in Clinical Medicine, HN Sarker Page: 47; Long Cases in Clinical Medicine, ABM Abdullah Page: 187

Remember the following points in elderly patient:

• AS is the most common form of valve disease in old age.
• It is a common cause of syncope, angina and heart failure in this age group.
• Low pulse pressure and slow rising pulse may not be present due to stiffening of the arteries.
• Surgery can be successful in the absence of comorbidity, but operative mortality is higher. Prognosis is poor in symptomatic patients without surgery.
• Biological valve is more preferable than mechanical valves. Anticoagulant is not needed.

* Short Cases in Clinical Medicine, ABM Abdullah, 5th Edition Page: 83; Davidson’s Principles and Practice of Medicine, 22nd Edition Page: 643