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Aortic regurgitation

Definition

  • A reflux of blood from the aorta back through the aortic valve into the left ventricle during diastole, results from aortic valve damage/abnormalities

 

Risk factors

  • Congenital aortic valve abnormalities
  • Acute rheumatic fever/rheumatic heart disease
  • Infective endocarditis
  • Aortic dissection
  • Syphilis
  • Rheumatoid arthritis
  • Ankylosing spondylitis
  • Marfan’s syndrome
  • Lupus
  • Ehlers-Danlos syndrome
  • Turner syndrome
  • Osteogenesis imperfecta
  • Severe hypertension

 

Differential diagnoses

  • Acute coronary syndrome
  • Aortic stenosis
  • Mitral stenosis
  • Mitral regurgitation
  • Infective endocarditis
  • Heart failure
  • Thyrotoxicosis
  • Severe anaemia
  • B12 deficiency
  • Arteriovenous fistula

 

Epidemiology

  • Prevalence estimates range from 2-30%, depending on severity
  • In UK, congenital and degenerative valve changes are most common causes
  • Peak age of onset is 40-60
  • Common after transcatheter aortic valve replacement

 

Aetiology

  • Regurgitation may be acute or chronic, usually with different causes
  • Acute aortic regurgitation is usually caused by infective endocarditis or trauma
    • Vegetations in infective endocarditis can lead to destruction or perforation of leaflets, or to prolapse
    • Trauma can damage the aorta, which disrupts the support structures for the valve
  • Bicuspid aortic valve is the most common congenital abnormality of the heart, and can cause chronic aortic regurgitation
  • Rheumatic fever/rheumatic heart disease lead to fibrosis and thickening of valve leaflets, preventing them from closing properly
  • A number of other disorders that can lead to accumulations in the valve tissue may cause chronic aortic regurgitation (see risk factors)

 

Clinical features

  • Symptoms usually appear late, not until left ventricular failure occurs
  • Heart pounding (increased LV size)
  • Angina pain
  • Dyspnoea/SOB
  • Arrhythmias can occur, but uncommon
  • Wide pulse pressure (difference between systolic and diastolic BP)
  • Pulse:
    • Bounding or collapsing
    • Quincke’s sign – capillary pulsation in nail beds (hyperdynamic circulation)
    • De Musset’s sign – head nodding with heart beat (hyperdynamic circulation)
    • Pistol shot femorals – sharp bang heard on auscultation over femoral arteries with each heart beat (hyperdynamic circulation)
  • Palpation
    • Apex beat displaced laterally and downwards
    • Forceful apex beat
  • Auscultation
    • Early diastolic murmur, high pitched
    • Best heard at left sternal edge, 4th intercostal space, patient leaning forwards and holding breath out
    • Radiates to neck
    • Commonly also ejection systolic murmur (because of volume overload)

 

Pathophysiology

  • Reflux of blood through aortic valve back into left ventricle during diastole
  • To maintain cardiac output, must increase volume of blood pumped into aorta
  • So left ventricle must increase in size
    • Less efficient
    • Greater O2 demand
    • Ischaemic pain/angina
  • Diastolic blood pressure falls because some blood is re-entering the left ventricle during diastole

 

Investigations

  • CXR
    • Left ventricular enlargement
    • Possible dilatation of ascending aorta
    • Calcification of aortic valve, or possible ascending aorta (syphilis)
  • ECG
    • Left ventricular hypertrophy
    • Tall R waves
    • Deeply inverted T waves in left chest leads
    • Deep S waves in right chest leads
    • Normally sinus rhythm
  • Echocardiogram
    • Dilated left ventricle
    • Vigorous contraction
    • Possible aortic root enlargement
    • Severity is assessed using colour Doppler and CW Doppler
  • Cardiac MRI can be used to quantify regurgitant volume, and assessing aorta
  • Cardiac catheterisation to assess for coronary artery disease in patients requiring surgery, involves injection of contrast media to outline valvular abnormalities

 

Management

  • Treat/manage underlying cause/precipitation factor if relevant
  • Vasodilation and ionotropes in acute aortic regurgitation
  • ACE inhibitors if left ventricular dysfunction
  • Beta-blockers to slow aortic dilatation eg in Marfan syndrome
  • Symptoms don’t usually present until heart failure is present, which won’t fully recover even after valve replacement
    • Valve replacement best before symptoms occur
  • Aortic surgery when:
    • Acute severe aortic regurgitation
    • Symptomatic patients with chronic severe regurgitation
    • Symptomatic patients with left ventricular ejection fraction <50%
    • Asymptomatic patients with LV ejection fraction >50%, but with dilated left ventricle (end-diastolic >70mm, systolic >50mm)
    • If undergoing CABG, or other aortic/valve surgery
  • Mechanical valves and tissue valves used
  • Tissue valves preferred in the elderly, as anticoagulants need be given for mechanical valves
  • Tissue valves contraindicated in children and young, because of rapid calcification and degeneration

 

Prognosis

  • Prognosis depends on the severity and progression of left ventricular dysfunction
  • In asymptomatic patients, progression rate to symptomatic in 1 year is over 25%
  • In symptomatic patients, mortality in 1 year is over 10%
  • Severe acute aortic regurgitation has high mortality

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