Aortic regurgitation

Notes

Definition & classification

Aortic regurgitation results from an incompetent aortic valve causing a regurgitant flow of blood in diastole.

Aortic regurgitation tends to present between the fourth and sixth decades of life. It affects males three times more commonly than women. Severe disease is seen in < 1% of the population. The most common causes are degenerative disease and congenital bicuspid valve.

Aetiology

Causes of AR can be split into either primary disease of the aortic valve leaflets; or dilation of the aortic root.

Aetiology of AR

Valve leaflets

Rheumatic heart disease

An autoimmune condition which follows streptococcal (Group A) infection. Inflammation is a result of molecular mimicry. In effect, the immune system produces antibodies that confuse foreign- and self-antigens. Rheumatic heart disease results from cardiac inflammation with acute and chronic results.

Commonest cause in the developing world. Although an increasingly uncommon cause of valvular disease. Chronic disease leads to fibrosis and typically a stenotic valve though regurgitant valves may also develop.

Congenital & degenerative

Constitute the commonest causes of aortic regurgitation in the developed world.

  • Congenital (e.g. bicuspid, quadcuspid valve).
  • Degenerative (e.g. calcification).

Endocarditis

Inflammation of the endocardium, typically as a result of infection. Results in acute disease. Vegetations may cause flailing of the valve leaflets. 

Infective causes include Strep. viridansStaph. aureusEnterococci.

Aortic root

Connective tissue disorders

Aortic regurgitation may feature in a number of connective tissue disorders. Aortic root diameter should be monitored in these individuals.

  • Marfan's syndrome - caused by a defect in the FBN1 gene.
  • Ehlers-Danlos syndrome - caused by collagen defects.

Aortitis

Inflammation of the aortic root. May be associated with chronic inflammatory conditions such as rheumatoid arthritis (RA) and ankylosing spondylitis (AS). Also, may occur in Takayasu arteritis, or may complicate Giant cell arteritis.

Aortic dissection

Occurs in Stanford A dissections, impairing leaflet coaptation or causing prolapse. Causes acute disease. A medical emergency.

Pathophysiology

Aortic regurgitation may develop acutely or chronically over a period of many years.

Acute & chronic AR

Acute

Acute aortic regurgitation is a medical emergency - an acute rise in left atrial pressure results in pulmonary oedema & cardiogenic shock.

Valvular incompetence occurs rapidly and the compensatory changes seen in chronic disease do not have time to develop. Regurgitation of blood during diastole causes an increase in the left ventricular end-diastolic volume (and pressure).

The effects of this are two-fold:

  • Reduced coronary flow - the coronaries fill predominantly during diastole, regurgitant flow at this time reduces filling. Results in angina or in severe cases myocardial ischaemia.
  • Increased end-diastolic pressure - causes increased pulmonary pressures with resulting pulmonary oedema and dyspnoea. In severe cases, cardiogenic shock may occur.

Chronic

In chronic aortic regurgitation, patients may remain asymptomatic for many decades.

Valvular incompetence develops slowly. Regurgitation of blood during diastole causes an increase in the left ventricular end-diastolic volume (essentially the preload). This leads to systolic and diastolic dysfunction, left ventricular dilatation develops with eccentric hypertrophy.

The dilation allows for an increased stroke volume compensating for regurgitant flow supported by the ventricular hypertrophy. These changes maintain ejection fraction, with a greater preload leading to greater contractility (see notes ‘Heart failure’ subsection ‘Frank-Starling law’).

Eventually further increases in preload cannot be met by greater contractility and heart failure develops.

Clinical features

Acute disease has the features of acute heart failure, the peripheral symptoms that are seen in chronic disease may not be present.

Acute AR

  • Sudden dyspnoea
  • Chest pain (consider angina, MI or aortic dissection)
  • Bi-basal crackles 
  • Raised JVP

Chronic AR

  • Palpitations 
  • Angina
  • Dyspnoea 
  • Water hammer pulse
  • Wide pulse pressure
  • Chest signs:
    • Displaced apex
    • Ejection diastolic murmur
    • Soft S1 and S2

Clinical features of aortic regurgitation

Eponymous signs

Often asked about in examinations, the relevance of these signs in clinical practice today is questionable.

  • de Musset’s - head nodding with the heart beat.
  • Quincke’s - pulsation of nail beds.
  • Traube’s - pistol shot femorals.
  • Duroziez’s - to and fro murmur heard when stethoscope compresses femoral vessels.
  • Müller’s - pulsation of uvula.

Eponymous signs of AR

Investigations & diagnosis

Bedside

  • Observations
  • Blood pressure
  • ECG
    • Left ventricular hypertrophy (deep S-waves in V1 and V2, tall R-waves in V5 and V6).
    • Left ventricular strain may be seen in severe disease.

Bloods

  • FBC
  • U&Es
  • Cholesterol
  • Clotting

Imaging

  • Echocardiogram
    • Allows visualisation of the origin of regurgitant jet and its width, detection of aortic valve pathology and ventricular hypertrophy.
  • CXR
    • ​May demonstrate cardiomegaly.
    • Dilated ascending aorta.
    • Calcification may be seen.

Special

  • Cardiac MRI
  • Cardiac catheterisation
  • ECG exercise stress testing

Management

Surgical aortic valve replacement or repair is indicated in severe or symptomatic disease. Severity is indicated on echo by LVH, pressure gradient and valve area. Successful surgery leads to much-improved quality of life and improved mortality.

Acute AR

Acute AR is a surgical emergency. Aortic valve replacement or repair should be performed as soon as possible.

Valve replacement

  • Mechanical valve - require long-term anticoagulation, long lifespan reducing the need for a second operation. Suited to younger patients.
  • Bioprosthetic valve - no need for long-term anticoagulation, limited life span (around 10 years) and a repeat operation is more likely. Suited to older patients.

The decision of mechanical vs bioprosthetic valve should take into account patient-specific factors and wishes. Traditionally valve replacement has necessitated open surgery, novel techniques now allow percutaneous replacement: transcatheter aortic valve replacement (TAVR) - a minimally invasive technique that utilises an expandable valve, may be used in patients who are not candidates for open surgery.

Coronary angiogram may be used to demonstrate atherosclerotic disease that may be treated with CABG at the same time as the open surgery.

Pulsenotes uses cookies. By continuing to browse and use this application, you are agreeing to our use of cookies. Find out more here.