Aortic regurgitation, also called aortic insufficiency may be caused by aortic root pathology or intrinsic valve disease and can manifest acutely or chronically. In this section, we will see the details of aortic regurgitation murmur and associated findings.
- This condition is due to inadequate closure of the aortic valve leaflets. Regurgitant blood flow increases left ventricular end-diastolic volume.
- LV dilation and hypertrophy occur in response in order to maintain stroke volume and prevent diastolic pressure from increasing excessively.
- Over time, these compensatory mechanisms fail, leading to increased left-sided and pulmonary pressures.
- The resting left ventricular EF is usually normal until advanced disease.
Course and Prognosis
- For chronic aortic regurgitation, survival is 75% at 5 years. After the development of angina, death usually occurs within 4 years. After the development of heart failure, death usually occurs within 2 years.
- For acute aortic regurgitation, mortality is particularly high without surgical repair.
Causes of Aortic Regurgitation
- Infective endocarditis
- Aortic dissection
- Iatrogenic as during a failed replacement surgery
- Primary valvular: Rheumatic fever, bicuspid aortic valve, Marfan syndrome, Ehlers–Danlos Syndrome, ankylosing spondylitis, SLE
- Aortic root disease: Syphilitic aortitis, osteogenesis imperfecta, aortic dissection, Behçet syndrome, Reiter syndrome, systemic HTN
Clinical Features of Aortic insufficency
- Maybe symptomatic for many years
- Dyspnea on exertion, PND, orthopnea
- Palpitations—worse when lying down
- Cyanosis and shock in acute aortic regurgitation (medical emergency)
- Physical examination
- Widened pulse pressure—markedly increased systolic BP, with decreased diastolic BP.
- Aortic regurgitation murmur is diastolic decrescendo murmur best heard at the left sternal border.
- Corrigan pulse (water-hammer pulse)—rapidly increasing pulse that collapses suddenly as arterial pressure decreases rapidly in late systole and diastole; can be palpated at wrist or femoral arteries.
- Austin Flint murmur—low-pitched diastolic rumble due to competing flow anterograde from the LA and retrograde from the aorta. It is similar to the murmur appreciated in mitral stenosis.
- Displaced PMI (down and to the left) and S3 may also be present.
- Murmur intensity increases with sustained handgrip. Handgrip increases systemic vascular resistance (SVR), which causes an increased “backflow” through the incompetent aortic valve.
Characteristic of Aortic Regurgitation murmur
Diagnosis of Aortic Regurgitation
- CXR findings: Enlarged cardiac silhouette, dilated aorta
- ECG findings: LVH
- Echocardiogram—Perform serially in chronic, stable patients to assess the need for surgery
- Assess LV size and function
- Look for dilated aortic root and reversal of blood flow in the aorta
- In acute aortic regurgitation, look for early closure of the mitral valve
- Cardiac catheterization: To assess the severity of aortic regurgitation and the degree of LV dysfunction
- Schedule immediate aortic valve replacement for patients with acute AR. Bridging medical therapy includes sodium nitroprusside and IV diuretics. Dobutamine or milrinone are also indicated if the BP is unacceptably low
- For chronic symptomatic AR, valve replacement is indicated regardless of LV systolic function. Valve replacement also is indicated for asymptomatic patients with LVEF <50%. Combined aortic root replacement with aortic valve replacement is used when an associated aortic root aneurysm is present.
- If symptomatic: Salt restriction, diuretics, afterload reduction (i.e., ACE inhibitors or ARBs), HFrEF therapy if heart failure (i.e., β-blocker, aldosterone antagonist, digoxin in selected cases), and restriction on strenuous activity