Aortic Stenosis (AS)
Aortic Stenosis (AS)
Aortic stenosis (AS) is a disease of the heart valves in which the opening of the aortic valve is narrowed.The aortic valve is the valve located between the left ventricle of the heart and the aorta, the largest artery in the body, which carries the entire output of blood to the systemic circulation. Aortic stenosis is now the most common valvular heart disease in the Western World.
Aortic Stenosis
Etiology of Aortic Stenosis
Rheumatic (commonly associated with mitral valve disease),
Calcific (degenerative),
< 70 years usually bicuspid aortic valve,
>70 years usually 3 cusps.
Rare causes of aortic stenosis include Fabry disease, systemic lupus erythematosus, Paget disease, hyperuricemia, and infection.
Symptoms of Aortic Stenosis
Most people with mild to moderate aortic stenosis are asymptomatic.The symptoms of aortic stenosis are syncope, anginal chest pain and dyspnea,orthopnea,Exertional syncope (fainting spells),Exertional dyspnoea,paroxysmal nocturnal dyspnea or pedal edema,Sudden death.
Diagnosis of Aortic stenosis
Aortic stenosis is most often diagnosed when it is asymptomatic and can sometimes be detected during routine examination of the heart and circulatory system.
Physical Examination
JVP- prominent ‘a’ waves,
Narrow pulse pressure,
Pulsus parvus / tardus,
Apical heave, usually not displaced unless there is failure,
Palpable S4 (Vigorous left atrial contraction)
Absent to faint A2, often withparadoxical split
Systolic ejection click, suggests mobile cusps, particularly common in congenital Aortic Stenosis
Harsh loud ejection systolic murmur in aortic area conducted to carotids and to apex
Often accompanied by thrill
Amyl nitrate increases murmur and Valsalva decreases it.
X-ray Chest
Post stenotic dilatation of ascending aorta,No Cardiomegaly unless in Congestive Heart Failure or associated Aortic Regurgitation (AR),Calcification of valve in fluoroscopy.
Aortic Stenosis
ECG
Left Ventricular Hypertrophy (LVH),Left Atrial Enlargement (LAE),AV block (when calcification extends to conduction system).
Aortic Stenosis
Echo
Shows number of cusps, size of orifice.
Thick, calcified cusps with poor mobility (doming).
Aortic Stenosis
Left Ventricular Hypertrophy and Left Atrial Enlargement.
Increased gradient across aortic valve.
Aortic Stenosis
Cardiac catheterization
Cardiac chamber catheterization provides a definitive diagnosis, indicating severe stenosis in valve area of <1.0 cm2 (normally about 3 cm2).It can directly measure the pressure on both sides of the aortic valve. The pressure gradient may be used as a decision point for treatment. It is useful in symptomatic patients before surgery.However, cardiac catheterization is not recommended to assess the severity of aortic stenosis when noninvasive testing is sufficient to make the diagnosis.
Treatment of Aortic stenosis
In general, medical therapy has relatively poor efficacy in treating aortic stenosis. However, it may be useful to manage commonly coexisting conditions that correlate with aortic stenosis:
Angina is generally treated with beta-blockers and/or calcium blockers. Nitrates are contraindicated due to their potential to cause profound hypotension in aortic stenosis.
Hypertension is treated aggressively, but caution must be taken in administering beta-blockers.
Heart failure is generally treated with digoxin and diuretics, and, if not contraindicated, cautious inpatient administration of ACE inhibitors.
Balloon Valvulotomy if non calcified, especially in children.A balloon is inflated to stretch the valve and allow greater flow, may also be effective. In adults, however, it is generally ineffective, as the valve tends to return to a stenosed state. The surgeon will make a small incision at the top of the patient’s leg and proceed to insert the balloon into the artery and then inflate it to get a better flow of blood around the patient’s body.
Surgery (Valve replacement)Gradient across aortic valve exceeds 50 mg Hg.Valve area <0 .75cm2. Transcatheter Aortic Valve Replacement (TAVR)
Globally more than 40,000 patients have received transcatheter aortic valve replacement. For patients who are not candidates for surgical valve replacement, transcatheter valve replacement may be a suitable alternative. When selecting the optimal therapy for individual patients, the percutaneous (transcatheter) approach must be carefully weighed against the excellent results achieved with conventional surgery.
Apicoaortic conduit
ApicoAortic Conduit (AAC), or Aortic Valve Bypass (AVB), has been shown to be an effective treatment for aortic stenosis.There is long-term stability of the left ventricular hemodynamics after AVB, with no further biologic progression of native aortic valve stenosis. Once the pressure gradient across the native valve is substantially reduced, the narrowing and calcification of the native valve halts.
Prognosis of Aortic Stenosis
If untreated, severe symptomatic aortic stenosis carries a poor prognosis with a 2-year mortality rate of 50-60% and a 3-year survival rate of less than 30%
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