AORTIC STENOSIS

Etiology:
  • Congenital (bicuspid, unicuspid), Degenerative calcific, Rheumatic fever, Radiation
  • Symptoms:
  • AS is rarely of clinical importance until the valve orifice has narrowed to approximately 1 cm2.
  • Once symptoms occur, valve replacement is indicatedQ.
  • Most patients with pure or predominant AS have gradually increasingQbstruction over years, but do not become symptomatic until the sixth to eighth decadesQ
  • Exertional dyspnea, angina pectoris, and syncope are the three cardinal symptomsQ
  • Often, there is a history of insidious progression of fatigue and dyspnea associated with gradual curtailment of activities Q
  • Because the CO at rest is usually well maintained until late in the course, marked fatigability, weakness, peripheral cyanosis, cachexia, and other clinical manifestations of a low CO are usually not prominent until this stage is reachedQ
  • Orthopnea, paroxysmal nocturnal dyspnea, and pulmonary edema, i.e., symptoms of LV failure, also occur only in the advanced stages of the diseaseQ
  • Severe pulmonary hypertension leading to RV failure and systemic venous hypertension, hepatomegaly, AF, and TR are usually late findings in patients with isolated severe ASQ Death in patients with severe AS occurs most commonly in the 7th and 8thdecades Q
General Considerations
  • Most often as result of degeneration of bicuspid aortic valve
  • Less commonly rheumatic heart disease or secondary to degeneration 
  • of a tricuspid aortic valve in person > 65 
Location
  • Supravalvular
  • Uncommon
  • Associated with William’s Syndrome
  • Hypercalcemia
  • Elfin facies
  • Pulmonary stenoses
  • Hypoplasia of aorta
  • Stenoses in
  • Renal, celiac, superior mesenteric arteries
Valvular Most common
  • Either congenital (from a bicuspid aortic valve) or acquired
  • Bicuspid aortic valve is the most common congenital cardiac anomaly
  • 0.5 –2%
Subvalvular
  • Associated with
  • Hypoplastic left heart syndrome
  • Idiopathic Hypertrophic Subaortic Stenosis
  • Hypertrophic cardiomyopathy
  • Subaortic fibrous membrane 
Types
  • Congenital aortic stenosis (more common)
  • Most frequent congenital heart disease associated with 
  • intra-uterine growth retardation (IUGR)
  • Subvalvular (30%)
  • Valvular (70%)
  • Degeneration of bicuspid valve
  • Supravalvular
Acquired aortic stenosis
  • Rheumatic valvulitis
  • Almost invariably associated with mitral valve disease
  • Fibrocalcific senile aortic stenosis
  • Degenerative 
Clinical Findings
  • Asymptomatic for many years
  • Classical triad
  • Angina
  • Syncope
  • Shortness of breath (heart failure)
  • Systolic ejection murmur
  • Carotid pulsus parvus et tardus
  • Diminished aortic component of 2nd heart sound
  • Sudden death in severe stenosis after exercise
  • Diminished flow in coronary arteries causes ventricular dysrhythmias
  • and fibrillation
  • Decompensation leads to left ventricular dilatation and pulmonary 
  • venous congestion
DIAGNOSIS:

Auscultation:
  • An early systolic ejection sound is frequently audible in children, adolescents, and young adults with congenital BAV disease Q.
  • Paradoxical splitting of S2Q
  • S4: Audible at the apexQ
  • S3 generally occurs late in the courseQ
  • Ejection (mid) systolic murmur Q
  • Ejection (mid) systolic murmur in AS
  • Commences shortly after the SiQ
  • Increases in intensity to reach a peak toward the middle of ejection Q
Ends just before aortic valve closure Q
  • Characteristically low-pitched, rough and rasping in character, and loudest at the base of the heart, most commonly in the 2" right intercostal space Q.
  • Transmitted upward along the carotid arteriesQ
  • Occasionally, transmitted downward and to the apex, where it may be confused with the systolic murmur of MR (Gallavardin effect Q).
Echocardiography:
  • The key findings on TTE are thickening, calcification, and reduced systolic opening of the valve leaflets and LV hypertrophy Q.
  • Eccentric closure of the aortic valve cusps is characteristic of congenitally bicuspid valvesQ
  • Severity of AS Valve Area
  1. Mild           →   1.5-2 cm2
  2. Moderate   →   1-1.5 cm2
Severe
  • Echocardiography is useful for identifying coexisting valvular abnormalities; for differentiating valvular AS from other forms of LV outflow obstruction: and for measurement of the aortic root and proximal ascending aortic dimension Q.
  • Dobutamine stress echocardiography is useful for the evaluation of patients with AS and severe LV systolic dysfunction (EF < 0.35), in whom the severity of the AS can often be difficult to judge.
Imaging Findings
  • In older children or young adults
  • Prominent ascending aorta
  • Poststenotic dilatation of ascending aorta
  • Due to turbulent flow
  • Left ventricular heart configuration
  • Normal-sized or enlarged left ventricle
  • Concentric hypertrophy of left ventricle produces a relatively small
  • left ventricular chamber with thick walls
  • Heart size is frequently normal
  • In adults >30 years
  • Prominent ascending aorta
  • Poststenotic dilatation of ascending aorta
  • Due to turbulent flow
  • Calcification of aortic valve (best seen on RAO)
  • Normal to enlarged left ventricle
Exam Question
  • Dicrotic nature of aortic notch is lost in Aortic Stenosis
  • Aortic Stenosis is common manifestation of congenital Rubella
  • Aortic stenosis is an absolute contraindication for exercise testing
  • The pressure-volume curve is shifted to the left in Aortic stenosis
  • In heart patient the worst prognosis during pregnancy is seen in Aortic stenosis
  • Aortic stenosis in young age is due to Bicuspid valve
  • Calcification of the aortic valve is seen in Aortic stenosis
  • Severity of Aortic stenosis is determined by Late ejection systolic murmur & ST -T changes
  • Pure left sided failure may be seen with Aortic stenosis
  • William's syndrome is associated with Congenital Supravalvular Aortic stenosis
  • Angina pectoris and Syncope are most likely to be associated with Aortic stenosis
  • Triad of angina, syncope and congestive heart failure can be suspected to have Aortic stenosis
  • Aortic stenosis is a valvular heart diseases is most commonly associated with sudden death
  • In severe aortic stenosis ST segment changes in ECG
  • Delayed peak of systolic murmur is seen in a patient with severe aortic stenosis
  • In Patient of Aortic stenosis with Exercise Stress testing terminated at 11 minutes due to development of fatigue and dyspnea. Regional pressure gradient was observed to be 60 mm Hg between the two sides of the aortic valve.Best Management is Aortic valve replacement
  • Sub-valvular Aortic Stenosis is known to be associated with AR, VSD & Coarctation of Aorta
  • The most common complication of Sub-valvular Aortic Stenosis is Aortic Regurgitation
  • Aggravation of symptoms of angina in a patient when given nitrates is seen in Idiopathic hypertrophic subaortic stenosis
  • Pressure difference of 5mm Hg between the two upper limbs occurs in Supra –valvular aortic stenosis 
  • Most common cause of death in aortic stenosis patients is IHD with ventricular fibrillation
  • Vasopressor of choice in anesthesia for a patient of aortic stenosis, who develops hypotension during surgery is Phenylephrine
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