Aortic Stenosis vs Mitral Regurgitation


Aortic stenosis 

Aortic valve stenosis is the most common cause of left ventricular outflow obstruction in children and adults.

An ejection-systolic murmur, heard on the right 2nd ICS, radiating to carotid arteries


Mitral regurgitation

Mitral regurgitation (MR), which is also known as mitral insufficiency, is a common heart valve disorder. When MR is present, blood leaks backwards through the mitral valve when the heart contracts. This reduces the amount of blood that is pumped out to the body.

A pansystolic murmur, heard on the left 5th ICS, MCL, radiating to the axilla


Aortic stenosis

  • Approximately 2% of people over the age of 65,  3% of people over age 75, and 4% percent of people over age 85 have aortic valve stenosis.¹
  • The prevalence is increasing with the ageing population in North America and Europe.
  • Degenerative calcific aortic stenosis usually manifests in individuals older than 75 years.

Mitral regurgitation

  • MR affects males and females equally.
  • 2% population.
  • 2nd most common


Aortic stenosis

  • Age related degenerative sclerocalcific changes to the valves
  • Congenital bicuspid aortic valve – e.g. Williams syndrome


Mitral regurgitation

  • Mitral valve prolapse (“Parachuting & Bulging → Regurgitation):
    • SLE / Marfan’s / Ehler Danlos
  • Rheumatic mitral valve disease
  • Ischaemic injury – MI →  Papillary muscle damage
  • Endocarditis “vegetations”
  • Secondary annular dilatation from LV dysfunction
  • Congenital – Down’s syndrome

Risk factors

The major risk factors for acquired heart valve disease are:

  • Age
  • Heart disease risk factors: hypercholesterolaemia, hypertension, smoking, insulin resistance, diabetes, overweight/obesity, lack of physical activity and a family history of early heart disease.
  • Risk factors for endocarditis (such as intravenous drug use)


Aortic stenosis

  • Chest pain
  • Weakness / Dizziness (presyncope / syncope)
  • Dyspnoea


Mitral regurgitation

  • Dyspnoea
  • Orthopnea & PND
  • Ankle swelling
  • Palpitations
  • Reduced exercise tolerance
  • Fever, rigors & malaise – in infective causes of MR


Aortic stenosis

Slow rising pulse


Pulsus bisferiens – double peak per cardiac cycle – feel in brachial/femoral pulse

Ejection systolic murmur:

  • Best heard at 2nd intercostal space – right sternal border
  • Radiates to carotid arteries
  • Severe aortic stenosis – inaudible S2 (calcified valve)

Mitral regurgitation

Soft S1 & S2

S3 / Gallop rhythm

Pansystolic murmur:

  • Left 5th intercostal space – midclavicular line
  • Radiation to axilla

Differential diagnosis

Aortic stenosis

  • Aortic sclerosis
  • Ischaemic heart disease
  • Hypertrophic cardiomyopathy (HCM)
  • Mitral regurgitation


Mitral regurgitation

  • Acute coronary syndrome
  • Infective endocarditis
  • Mitral stenosis
  • Aortic stenosis
  • Atrial myxoma



Aortic stenosis – LVH / Left ventricular strain

Mitral regurgitation – LVH / Broad P-waves (left atrial enlargement) / AF



Aortic stenosis – Cardiomegaly (enlarged left ventricle) // Calcification of aortic ring

Mitral regurgitation – enlarged left atrium / left ventricle // pulmonary oedema



  • Allows direct visualisation of valve dysfunction
  • Can also assess ventricular function/wall thickness
  • Can assess severity of AS – pressure gradients etc
  • Trans-oesophageal echo (TOE) should be considered if transthoracic echo doesn’t provide adequate image quality



  • Can provide more detailed imagery of the heart & valve of interest
  • It can assess the ascending aorta for pathology
  • It can help assess valve area & the amount of calcification


Cardiac catheterisation

  • Sometimes required to accurately measure pressure gradients across a given valve

Coronary angiography:

  • Often performed to provide more information about coronary risk, which is important when a patient is being considered for valve replacement.


Aortic stenosis

Symptomatic patients require early surgical intervention because no medical therapy for AS is able to improve outcome.


Medical therapy

Modification of atherosclerotic risk factors is strongly recommended. Aortic stenosis in the older age group should be seen as a strong risk for ischaemic heart disease: ²

  • Statins
  • Antihypertensives – being careful not to induce hypotension
  • Smoking cessation & dietary advice


If the patient is unsuitable for surgical intervention:

  • Digoxin / Diuretics / ACE inhibitors – to provide symptomatic relief from heart failure symptoms
  • Maintenance of sinus rhythm is important – use antiarrhythmic drugs as required

Aortic valve replacement

Aortic valve replacement (AVR) is the definitive therapy for severe AS.

Operative mortality of AVR for AS:

  • 1-3% in patients < 70 years
  • 4-8% in older adults

Early valve replacement is strongly recommended for all symptomatic patients with severe AS who are suitable for surgery.


Transcatheter aortic valve implantation (TAVI)

TAVI is a recent development and provides a method of AVR which does not carry the same risks as surgical AVR mentioned above.


What does TAVI involve?

TAVI can be performed under a general anaesthetic or under local anaesthetic with sedation, making it a consideration in patients who are unsuitable for surgical AVR.

TAVI involves the replacement of the aortic valve of the heart via the blood vessels (not requiring open heart surgery).  The replacement valve is delivered via one of several access methods: transfemoral (in the upper leg), transapical (through the wall of the heart), subclavian (beneath the collarbone) and direct aortic (through a minimally invasive surgical incision into the aorta).  The whole procedure occurs under fluoroscopy and echocardiography guidance.


Key points:

  • The procedure is less invasive and carries fewer risks than a surgical aortic valve replacement.
  • The procedure is of equal efficacy as surgical AVR in patients who are unsuitable for surgery.
  • As with any surgical procedure, there are associated risks which include major bleeding, stroke, arrhythmias, MI, Aortic Dissection and residual aortic regurgitation.


Balloon valvuloplasty

This procedure involves widening of a stenotic aortic valve using a balloon catheter inside the valve. The balloon is inflated in an effort to increase the opening size of the valve and improve blood flow.

Current evidence supports the safety and efficacy of balloon valvuloplasty for aortic valve stenosis in adults and children.³

However, restenosis and clinical deterioration occur within 6-12 months in most patients.³

In adults, the procedure is only used to treat patients who are unsuitable for surgery, due to the efficacy usually being short-lived.


Mitral regurgitation

Medical management is non-curative and is indicated in mild to moderate disease, or in those unsuitable for surgery:

  • Acute MR – Diuretics / Sodium Nitroprusside / Positive inotropes
  • Chronic MR – ACE inhibitors / Beta blockers / Spironolactone


Surgery is indicated in the following situations:

  • Patients with MR who are symptomatic
  • Impaired LV function (regardless of symptoms).
  • Pulmonary hypertension
  • New onset atrial fibrillation
  • Acute MR secondary to rupture of papillary muscle or chordae tendinae


There are two main surgical options for MR, but the choice depends upon the pathology:

  • Mitral valve repair – preferred as prosthetic valves have a limited lifespan of 10-15 years
  • Mitral valve replacement


The choice of replacement valve (mechanical vs biological) requires careful analysis of individual clinical factors and preferences:

  • Age of patient
  • Presence of atrial fibrillation
  • Prior CVA
  • PE
  • Other mechanical prostheses
  • Presence of renal failure
  • Prior bleeding issues
  • Compliance with warfarin
  • Lifestyle, occupational and personal preferences


Anticoagulation is required with replacement valves, but the choice of anticoagulation treatment depends upon a number of individual factors:

  • Type of valve – risk is greater with mechanical valves
  • Site of valve replacement – risk is greater with mitral valve (vs aortic valve)
  • The presence or absence of  other underlying risk factors for thrombus formation

Patients with prosthetic heart valves are at a high risk for endocarditis and should use prophylactic antibiotics in accordance with current guidelines.


Infection of prosthetic valves – 60% mortality rate –  within 6 months of implantation, it is usually due to colonisation by Staphylococcus epidermidis.

Valve obstruction, thrombosis or pannus formation – treated with surgical correction.

Systemic embolisation – arise from valve thrombosis, vegetations or left atrial thrombus.


Haemolytic anaemia – more common with mechanical than bioprosthetic valves – usually mild and subclinical.


Mechanical valves lifespan 20-30 years

Bioprosthetic valves 10-18 years

Multiple prognostic factors based on patients’ co-morbidities


  1. Manning WJ (October 2013). “Asymptomatic aortic stenosis in the elderly: a clinical review”. JAMA 310 (14): 1490–7. doi:10.1001/jama.2013.279194.PMID 24104373.


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