Low Gradient Aortic Stenosis

From Ask Dr Wiki

Definition: Aortic Valve gradient < 30 mmHg and a AVA <1.0 cm2 in association with low flow (flow=SV and systolic ejection period)

Important because AS and a low transvalvular pressure gradient due to significant LV failure may have considerable operative risk….

“Pseudostenosis” moderate aortic stenosis and low cardiac output thus low output reduces the valve opening forces limited mobility of a valve that is not severely diseased

Gorlin equation for AVA tends to underestimate the valve area when cardiac output is low (<175 ml/sec)

AVA (in cm²) = (SV ÷ SEP) ÷ (44.3 x [sq rt P])

No operative benefit and treat the primary myocardial issues

True Stenosis with LV dysfunction

stenotic lesion results in excessive afterload and a reduced LVEF and decreased stroke volume and low transvalvular pressure gradient results

Differentiation: “contractile reserve”

*Dobutamine Stress Echo:

• Pseudostenosis:increased stroke volume, AVA, decrease in valve resistance
• True AS: increase in the mean gradient; no change in AVA

ACC/ASE: “usefulness is less well established in low flow…”