AORTIC STENOSIS

AORTIC STENOSIS

AORTIC STENOSIS Bicuspid valve Degenerative calcific valve Rheumatic valve

AORTIC STENOSIS Valve area (cm2) normal - 3.0 – 4.0 mild AS - 1.5 – 2.0 moderate AS - 1.0 – 1.5 severe AS - < 1.0 ( < 0.6 cm2 / m2 ) critical AS - < 0.75 ( < 0.5 cm2 / m2 )

AORTIC STENOSIS Rate of progression ( annual ) Area - decrease by 0.12 cm2 Jet velocity - increase by 0.32 m / sec Mean gradient - increase by 7 mm Hg

AORTIC STENOSIS Clinical Remain asymptomatic for long Severe AS exertional angina , syncope / presyncope dyspnea low volume, slow rising pulse – parvus et tardus narrow pulse pressure prominent A in JVP (Bernheim effect) heaving apex LV S4 , delayed A2 long MSM with late peaking LV strain pattern in ECG

AORTIC STENOSIS

AORTIC STENOSIS Geometric orifice area (GOA) … minimal area by planimetry Effective orifice area (EOA) …. by continuity equation corresponds to venacontracta

AORTIC STENOSIS Hemodynamics

AORTIC STENOSIS Pressure recovery Peak gradient by Doppler

Cath Echo Mean gradient

AORTIC STENOSIS Echocardiography Anatomy - short & long axis views (occasionally TEE / 3D) 2. LVOT diameter – midsystole ; at the site of measurement of LVOT velocity measurement parallel to AV 3. LVOT velocity - apical 4C / 5C ; V max / VTI 4. AS jet velocity (CW) – V max; peak and mean gr; VTI 5. SVI 6. DSE ( SOS)

AORTIC STENOSIS Primary data AS jet velocity – V max mean gradient valve area flow .. SVI Continuity equation Planimetry .. TTE / TEE / 3D Gradient …. Diagnostic value Flow ………. Prognostic value

AORTIC STENOSIS Continuity equation Flow across LVOT and aortic valve is same Flow = area x VTI A LVOT x VTI LVOT = A AV x VTI AV AAV = A LVOT x VTI LVOT A1 x V1_ VTI AV V2

AORTIC STENOSIS Dimensionless valve index (velocity ratio) Very simple method Variable of area is taken away from the continuity equation LVOT velocity Aortic valve velocity Value < 0.25 .. Severe AS

SEVERE AS Mean gradient = 71 mm Hg Dimensionless index = 0.5 / 5.5 = 0.1

V1 = 1. 5 m /sec V 2 = 4 m / sec DI = 1.5 / 4 = 0.375

AORTIC STENOSIS Severity Parameters sclerosis mild AS moderate severe Vmax..m/sec < 2.5 2.6 – 2.9 3.0 – 3.9 ≥ 4.0 MPG mm Hg -- < 20 20 – 39 ≥ 40 AVA cm2 -- > 1.5 1.0 – 1.5 < 1.0 AVAI cm2 / m2 -- > 0.85 0.6 – 0.85 < 0.6 Dimensionless -- > 0.5 0.25 – 0.5 < 0.25 index

AORTIC STENOSIS Global LV hemodynamic load Valvuloarterial impedance ( Z va ) Valvular resistance + vascular resistance Mean gradient SBP Zva = SBP + mean gradient Stroke volume index > 4.5 … severe AS

AORTIC STENOSIS Dobutamine stress echo change in mean gradient change in valve area change in SVI effort tolerance , symptoms BP response increase in mean gradient Exercise test in severe “asymptomatic” AS BNP .. Limitations + ; > 500 pg / ml …poor prognosis

AORTIC STENOSIS CT best method to assess annulus, aorta and calcium assess GOA assess coronaries severity of AS .. < 700 AU .. excludes severe AS > 2000 AU .. severe AS > 1650 .. optimal sensitivity & specificity evaluation of prosthetic valve planning TAVR assess myocardial fibrosis CMR

AORTIC STENOSIS Terminologies Low flow low gradient severe AS Paradoxical low flow AS Pseudosevere AS

AORTIC STENOSIS Low flow low gradient AS Valve area < 1.0 cm2 Mean gr. < 40 mm Hg SVI < 35 ml / m2 ? Possibilities EF < 50 % EF > 50 % severe AS with reversible LV dysfunction AS with severe myocardial failure pseudo severe AS paradoxical low flow severe AS (EF > 50 %)

AORTIC STENOSIS Physiologic discrepancies V max > 4.0 m /sec Mean gr. > 40 mm Hg Valve area > 1.0 cm2 Valve area < 1.0 cm2 ; normal flow ; low gradient Gradient under assessed due to hypertension Prolonged LVET ; reduced flow rate > lower Vmax Moderate AS ; small body size ; AVA index - > 0.6 cm2 1. 2. associated AR high output states Large BSA … calculate AVAI

AORTIC STENOSIS DSE Valve area mean gr. SVI change assessment (cm2) (mm Hg) ( %) < 1.0 > 40 > 20 severe AS myocardium OK < 1.0 < 40 < 20 myocardial failure ↑ by > 0.3 no change > 20 pseudo severe AS

AORTIC STENOSIS Paradoxical low flow severe AS ( Hachicha et al 2007) 1/3 rd of cases ; poor surgical outcome Severe true AS … area < 1.0 cm2 Low flow … SVI < 35 ml / m2 Preserved EF .. > 50 % 1. Impaired LVEDV 2. Impaired LV longitudinal strain severe LVH AF , tachycardia MS , MR, PAH, TR

D2 (low flow < 4.0 < 40 < 50 DSE .. gr > 40 Stages of valvular AS Stage type Vmax mean gr EF other data (m/sec) (mm Hg) A at risk of AS < 2 -- N -- (BAV) B progressive AS 2.0 – 3.9 upto 39 N valve area > 1.0 Asymptomatic ≥ 4.0 ≥ 40 N ( C1) valve area < 1.0 severe AS < 50 % (C2) D Symptomatic severe AS (valve area < 1.0) D1 (high gr) ≥ 4.0 ≥ 40 N D2 (low flow < 4.0 < 40 < 50 DSE .. gr > 40 low gr) SVI > 35 D3 (paradoxical < 4.0 < 40 > 50 DSE .. SVI < 35 low flow low gr)

AORTIC STENOSIS Surgery Class I Class II a Class II b symptomatic severe AS .. Stage D1 asymptomatic severe AS ; EF < 50 % .. C2 asymptomatic severe AS + other cardiac surgery very severe AS ( Vmax > 5 m/sec ; mean gr . 60 mmHg) abnormal ETT low flow low gradient AS with contractile reserve on DSE pseudo low flow severe AS asymptomatic severe AS with rapid progression V max > 0.3 m / s / year

AS .. (Vmax, mean gr., AVA, LVEF, SVI) MPG > 40 < 40 < 40 EF > 50 > 50 < 50 SVI > 35 < 35 < 35 Normal flow paradoxical low flow low flow low gr high gr. Vs pseudo severe AS DSE symptomatic symptomatic ? contractile reserve present absent AVR MPG > 40 AVA increase AVA < 1.0 by > 0.3 OMT