Aortic Valve Stenosis (AS)

by | Jul 28, 2015 | Cardiology |

Aortic Valve Stenosis (AS)

Symptoms:  dyspnea on exertion, dizziness/presyncope, angina, syncope (deadly)

Prognosis:  prognosis is worst for HF > syncope > angina

Physical Exam:

  • Late-peaking systolic ejection murmur (SEM), crescendo-decrescendo, may radiate to carotids, +/- thrill
  • Single S2 (especially on inspiration)
  • Carotid pulses attenuated (parvus) and delayed (tardus)
  • +/- S4 heart sound in sinus rhythm
  • +/- sustained apical impulse
  • AS severity is worse with late-peaking
  • AS increases with amyl nitrite (worsens gradient)
  • AS decreases with standing and Valsalva maneuver (reduces preload)

Causes:  senile degenerative #1 (esp. > 70 yo);  bicuspid, congenital, calcific, rheumatic

Differential Dx:  supervalvular stenosis, subvalvular stenosis, hypertrophic obstructive cardiomyopathy

A note on Bicuspid AS:  + AV ejection click, associated with coarcted aorta, you must image aorta (CT/MRI) and screen 1st degree relatives

AS Stages:

  • A:  At risk
  • B:  Progressive AS
  • C:  Asymptomatic Severe AS:  C1 = normal LVEF,  C2 = LVEF < 50%
  • D:  Symptomatic Severe AS:  D1 = high gradient,  D2 = low flow/gradient/LVEF,  D3 = nl EF, low gr&flow

Echocardiography of AS:

  • Severe AS:  peak velocity > 4 m/s,  mean gradient > 40 mmHg,  AVA < 1 cm(2),  LVOT:AV TVI < 0.25
  • AVA = CO / sqrt(gradient)                   AVA = (LVOT area x LVOT TVI) / AV TVI
  • Echo can underestimate AS if sampling is not parallel to valve
  • Echo can overestimate AS if pulse wave sampling volume is in the flow convergence zone
  • Dobutamine stress echo (DSE) is indicated for symptomatic severe AS with low EF (<50%), AVA < 1, and discrepant velocity or pressure data (peak velocity < 4 m/s or mean gradient < 40 mmHg)
  • Asymptomatic AS may be monitored by echo
    • Every 3-5 years for mild AS (Vmax 2-2.9 m/s)
    • Every 1-2 years for moderate AS (Vmax 3-3.9 m/s)
    • Every 6-12 months for severe AS (Vmax > 4 m/s)
  • If you’re stuck trying to differentiate severe AS from pseudo-severe AS (low EF):
    • Severe AS should have a constant LVOT:AV TVI with dobutamine stress
    • Dobutamine stress should increase LVOT:AV TVI in pseudo-severe AS (low EF)

Cardiac Catheterization and AS:

  • Cath is indicated when there is a discrepancy between stated symptoms and mean gradient
  • Brockenbrough phenomenon:  a PVC causes an increase of aortic pressure on the next beat
  • Carabello sign:  pullback of catheter across severe/critical AS causes increase in arterial BP
  • Don’t use femoral arterial pressure, Don’t cross in known severe AS (may cause a stroke)
  • Coexistent AS and AI may cause underestimation of AS severity
  • Pressure recovery phenomenon in cath overestimates AS severity vs. echo

Treadmill Exercise and AS:

  • In patients with asymptomatic severe AS and LVEF > 50%, operate if poor TMET
  • Don’t do a TMET on severe AS + Sx

Surgical Treatment of Severe AS (AVR if any of the following):

  • Severe AS + ANY symptoms of AS
  • Asymptomatic severe AS + LVEF < 50%
  • Asymptomatic Moderate-Severe AS + planned other cardiac surgery
  • Asymptomatic very severe AS (Vmax > 5 m/s or gradient > 60 mmHg) and low surgical risk
  • Asymptomatic severe AS + poor TMET test (reduced exercise tolerance, drop in BP, or BP rises < 20 mmHg).
  • Asymptomatic severe AS + worsening Vmax > 0.3 m/s/y

Surgical Treatment of Moderate AS (AVR if any of the following):

  • Moderate AS (Vmax 3-3.9 m/s or gradient 20-39 mmHg) + symptoms + LVEF < 50%
  • Moderate AS + other planned cardiac surgery

TAVR Indications:  high risk severe AS (STS score > 15) + indications for surgery + predicted survival > 12 mo.

Medical Management:  not curative, only supportive to surgery

  • Anti-hypertensives to GDMT
  • For severe AS and heart failure:  hemodynamic monitoring, careful IV nitroprusside and dopamine
  • No evidence of statin benefit

 

References:

Carabello BA and Paulus WJ.  Aortic Stenosis.  The Lancet.  2009 Mar 14;373(9667):956-66.

Nishimura RA, et al.  2014 AHA/ACC Guideline for the Management of Patients with Valvular Heart Disease.  J Am Coll Cardiol. 2014 Jun 10;63(22):2438-88.

Oh JK, Seward JB, and Tajik AJ.  The Echo Manual.  New York: Lippincott Williams & Wilkins, 2007.

Feldman T and Grossman W.  “Profiles in Valvular Heart Disease.” Chapter 28 in Cardiac Catheterization, Angiography, and Intervention.  New York:  Lippincott Williams & Wilkins, 2006.

 

Disclaimer    © 2015 www.markmccauleymd.com.  All rights served.