Aortic Stenosis

Aortic Stenosis

is the narrowing of aortic valve due to calcification of valve leaflets or valvular damage!

it commonly occurs in an early age in patients with congenital bicuspid aortic valves. 

MOST COMMON cause is calcifications with age, 70's

also results  Rheumatic Fever ( more commonly causes Mitral Stenosis)

1. SYNCOPE
2. CHEST PAIN
3. DYSPNEA ON EXERTION
4. SUDDEN CARDIAC DEATH - when stenosis progresses rapidly

PATHOPHYSIOLOGY

Aortic stenosis is narrowing of the aortic valve due to calcification of the valve leaflets or valvular damage.

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• Aortic stenosis commonly occurs at an early age in patients with congenital bicuspid aortic valves.
• The most common cause of aortic stenosis is calcification of the valve leaflets with age, with the prevalence of aortic stenosis increasing rapidly beginning in the 7th decade.
• Aortic stenosis can also result from rheumatic fever. Though rheumatic fever is most strongly associated with mitral stenosis, other valves may also be affected.

Aortic stenosis is classically associated with syncope, chest pain and dyspnea on exertion. Aortic stenosis can progress rapidly, leading to sudden cardiac death.

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• Aortic stenosis can lead to left ventricular hypertrophy as the myocardium contracts against the narrowed valve opening. The myocardium outgrows its blood supply, leading to ischemia, progressively worsening chest pain, and dyspnea from pulmonary congestion.
• Since aortic stenosis leads to myocardial ischemia and a fixed cardiac output, symptoms initially present during exercise. As the disease progresses, however, symptoms begin to occur at rest.

Aortic stenosis causes a pansystolic crescendo-decrescendo murmur heard loudest in the second intercostal space at the right sternal border.

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• The murmur often radiates to the carotid arteries.
• The murmur decreases in intensity with decreased preload (such as in the Valsalva maneuver).
• Aortic stenosis is associated with an S4 heart sound as well as “pulsus parvus et tardus,” or peripheral pulses that occur weak and late relative to the heartbeat, due to the slow emptying of left ventricle to the systemic circulation.
• CXR shows left ventricular hypertrophy.
• Echocardiography shows a narrowed valve area with increased transvalvular pressure gradient. Other findings may include left atrial enlargement and left bundle branch block.The most accurate way to quantify the transvalvular pressure gradient is with cardiac catheterization.
• Microangiopathic hemolytic anemia with schistocytes → hemoglobinuria

  • Recall that intravascular hemolysis also leads to decreased haptoglobin as well.
• ECG will often show left ventricular hypertrophy (LVH), left atrial enlargement (LAE), and left bundle branch block (LBBB). Severe dilation of the left atrium can result in Atrial Fibrillation in late disease.

Aortic stenosis can result in insufficient supply of blood to the systemic circulation, due to the inability of the left ventricle to compensate for decreased aortic valve area, resulting first in cardiac insufficiency or syncope.

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• Cardiac insufficiency may result in ischemic heart disease and heart failure, which entails a poor prognosis.

Aortic stenosis is managed medically to control hypertension, until patients face significant morbidity with their disease, at which point surgical valve replacement is called for.

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• Aortic Valve replacement (AVR) is the only effective treatment for severe AS (symptomatic AS) as well as asymptomatic AS with EF<50%. Other indications for replacement:

  • Aortic valve area <0.6cm2
  • Mean gradient >60mmHg
  • Aortic jet >5m/s
  • Decrease of BP with exercise
• Medical management is used in asymptomatic patients and symptomatic patients who are not surgical candidates. It consists of medication to control HTN and instructing patients to avoid vigorous physical exercise. Avoid venodilators (nitrates) and negative inotropes (calcium channel blockers/beta blockers) in severe aortic stenosis.
• Intra-aortic balloon pump (IABP) is used for stabilization and bridge to surgery.
• Balloon aortic valvotomy (BAV) results in approximately 50% increase in valve area but 50% restenosis at 6-12mos.