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Aortic Stenosis

Etiology

  • Narrowing of the aortic valve due to either congenital bicuspid aortic valve or more commonly age-related calcification (fibrocalcific) and degeneration of the valve due to atherosclerosis
    • Have a high rate of CAD: ⅓ in those 40-60 y/o and ⅔ in those >60 y/o
    • Heyde Syndrome
      • Characterized by the triad of aortic stenosis, GI bleeding from angiodysplasia, and acquired von Willebrand syndrome
      • Etiology
        • Increased circulatory shear forces and its effect on the physiologic confirmation and subsequent cleavage of large vWF multimers
      • Most often seen in men >65
      • Diagnosis: TTE + PFA
        • Confirm PFA w/vWF multimer analysis
      • Complications: GI bleeding
      • Treatment
        • Aortic Valve replacement is virtually curative
  • 3 MCC of Aortic Stenosis:

Types

  • Supravalvular Aortic Stenosis
    • 2nd Most common type of Aortic Stenosis
    • Usually refers to congenital left ventricular outflow tract obstruction due to discrete or diffuse narrowing of the ascending aorta
      • Systolic murmur as seen with valvular AS, but best heart at the right first intercostal space (higher than valvular AS)
      • ± unequal carotid pulses, differential blood pressure (high-pressure jet in ascending aorta), and a palpable thrill in the suprasternal notch
    • Develop LVH over time if significant and have coronary artery stenosis as an associated anomaly
      • Increased O2 demand, subendocardial or myocardial ischemia
    • Above aortic valve, LV outflow obstruction, LVH, exertional angina

Symptoms

  • Asymptomatic
    • Severe: 75% die or develop symptoms within 5 years
  • Classic Triad: Heart Failure, Angina, and Syncope with Exercise
  • Exertional dyspnea, lightheadedness or dizziness with exertion, chest pain, and syncope (late finding), progressive fatigue, and exertional lightheadedness and presyncope

Exam

  • Delayed carotid pulses, slowed upstroke (pulsus parvus et tardus)
    • Indicate severe stenosis but may be absent in older patients
    • Sustained apical impulse

Murmur

  • Mid to late peaking, diamond shaped systolic ejection murmur at RUSB or suprasternal notch that radiates to the neck
    • Typically asymptomatic unless AV area <1cm^2
  • Crescendo/decrescendo
    • The later the peak, the more severe the stenosis
    • Mild: Early peaking
    • Severe: Mid-Late peaking, paradoxical S2 split
      • May have Soft S2 if senile calcific
  • Soft single S2, delayed A2 on top of P2 = S2
    • A2 soft and delayed
  • S4 Gallop
    • Occurs as the result of left atrial kick against a stiff left ventricle if CHF is present due to Aortic Stenosis
  • May have systolic thrill over the upper precordium and suprasternal notch
  • Often decreased or absent aortic component of the 2nd heart sound due to decreased mobility of the aortic valve leaflets

Maneuvers

  • Louder with squatting, Softer with Valsalva
  • Right intercostal space radiating to carotids
    • May be transmitted to the apex instead of the neck (Gallavardin Effect)
  • Parvus et parvus/tardus pulse (slow rising/delayed pulse)
    • Usually age dependent, isolated

Classification

  • Severity determined by mean valve Pressure Gradient (PG), peak aortic jet velocity (Vmax), or Aortic Valve Area (AVA)
    • Mild: <25mmHg
    • Moderate: 25-40mmHg
    • Severe:
      • PG: ≥40mmHg or Vmax: ≥4.0m/s
        • HG-AS: AVR recommended
      • AVA: ≤1.0cm^2
        • LG-AS:
          • LF-LG: Reduced LVEF
          • Paradoxical LF-LG: Preserved LVEF w/SV <35
          • NF-LG: index SV ≥35
        • HG-AS: AVR recommended
  • Low flow (LVF) gives low pressure and velocity readings, need to determine valve area:
    • Mild: 1.9-1.6cm^2
    • Moderate: 1.5-1.1cm^2
    • Severe: ≤1cm^2
  • Low gradient AS (LG-AS)
    • AVA <1cm + Peak jet velocity ≤4.0ms and mean pressure gradient ≤40

Diagnosis confirmation

  • Severe: Doppler Ultrasound (TTE)
    • Discrepancy 2/2 low SV or CAD also:
      • Left Heart Cath or Dobutamine Echo

Prognosis

  • Survival without Surgical Intervention (SASH)
    • Survival in AS:
      • Angina = 5 years
      • Syncope = 3 years
      • Heart Failure = 2 years
    • Worst prognosis of all valvular lesions, medical therapy is not effective, use caution when treating VF with vasodilators if due to AS

Treatment

  • LHC prior to valve surgery in most
  • PARTNER-2: No difference in death or disabling stroke at 5 years after TAVR vs. SAVR for patients at intermediate surgical risk
  • Mild: TTE q3-5 years
  • Moderate: TTE q1-2 years
  • Severe Aortic Stenosis
    • TTE every 6-12 months, life expectancy 1-2 years with symptoms
    • Differentiate between pseudo-stenosis and true AS w/dobutamine stress test in low EF
    • Indications for valve replacement
      • Symptoms
      • LV systolic dysfunction EF <50% in an asymptomatic pt
      • Concomitant cardiac procedure (CABG, AA surgery)
  • TAVR > SAVR

    • 80 y/o, life expectancy <10 years, OR above

    • Must not have AR
  • Symptomatic, Ideal
    • SAVR: Surgical Aortic Valve Replacement
      • All Stage D
      • All Stage C with Severe disease on Testing, LVEF <50% w/symptoms (syncope, angina, dyspnea), or undergoing other cardiac surgery (CABG)
        • Valve treatment prior to elective noncardiac surgeries
    • TAVR: Transcatheter Aortic Valve Replacement
      • Use in pts with prohibitive risk for SAVR and predicted post-TAVR survival >12m
  • Shock/Pulmonary Edema
    • Consider Percutaneous Balloon Aortic Valvulotomy
  • Comorbid conditions