Download LOW GRADIENT AORTIC STENOSIS Sokolović S, Mundigler G

UNIVERSITY OF SARAJEVO
University Clinical Center
Clinic for heart and rheumatic diseases
AKH, University of Wien, Austria
STRESS ECHOCARDIOGRAPHY
in diagnosis of LOW FLOW - LOW GRADIENT
AORTIC STENOSIS
Sokolović S, Mundigler G. Naser N.
V. Kongres Kardiologa & Angiologa BiH, Sarajevo 27-29.5.2010.
Epidemiology of Aortic Stenosis
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AS is common
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> age 75:
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Long asymptomatic phase: risk of sudden death low
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Mortality ↑: exertional chest pain, syncope,
breathlessness
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Mortality up to 12% soon after onset of symptoms
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Significant AS and LV dysfunction: poor prognoses
3% SAA
Aortic Stenosis
Severity of AS with preserved LV :
Straightforward to evaluate
. Low Flow-Low Gradient AS, with
significantly reduced LV :
Dg challenge
STRESS TEST
 Stress
modalities:
Exercise
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Sitting bicycle
Supine bicycle
Threadmill
STRESS TEST
Pharmacological
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Dipyridamole – vasodilating
Adenosine – vasodilating
Dobutamine: as predominantly a B1adrenergic stimulating agent:Contractility
and HR ↑
Dobutamine: plasma half-life about 2 min.
DST INDICATIONS
INDICATION I:
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Diagnosis of ischemia:
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Better accuracy than exercise ECG
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DSE possible in patients unable to
exercise
DST INDICATIONS
After AMI:
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Early wall motion abnormality predicts new event
Remote wall motion abnormality predicts
multivessel disease.
Viability of akinetic area:
Sustained improvement: Good prognosis
Biphasic response: Good prognosis with
revascularisation, poor without.
DST INDICATIONS
Indications II:
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Before PCI / CABG: Significance of stenosis. : only
most severe stenosis usually responsive
Viability
After PCI / CABG: control for restenosis / graft
patency
CONTRAINDICATIONS
Dobutamine:
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Uncontrolled hypertension: >220/120 resting
Known hypertrophic obstructive cardiomyopathy.
Known malignant ventricular arrhythmia
Dipyridamole:
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AV-block
COPD
Aminofilin
TECHICAL REQUIREMENTS
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Personnel requirement: doctor and nurse minimum.
Patient fasting for 2 hours previously
Basic and advanced CPR available
Beta blockers discontinued for at least 24 hours
ECG & blood pressure monitoring
Echocardiography: continuous monitoring.
Recording of cine loops at baseline, low dose, high
dose, and recovery (optional)
Record 3 cycles
TERMINATION
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Side-by side comparison: Termination criteria:
Positive finding by echo: New wall motion abnormality
ST depression > 3 mm
BP limits:
> 220/120
< 70/systolic if good ventricular function
any BP drop > 100 mmHg if poor or reduced LV function
Arrhythmia: Non-sustained VT or sustained SVT
Intolerable symptoms (Angina, nausea)
Target Heart rate (> 85% of 220 -age)
Maximum dose (40 µg/kg/min + up to 1 mg atropine)
Positive stress echo test:
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.1 segment with new a-or dyskinesia or
. 3 segments with new hypokinesia
(= WMSI > 1.25 or increase by 0.25)
Additional criteria:
Post-systolic thickening
Diastolic abnormalities
Diagnostic value OF DST:
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Sensitivity: 80 -90%
If target HR reached
Specificity: 80 – 100 %
Comparable to perfusion scintigraphy
Definition of LF-LG AS
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Low gradient AS as severe aortic stenosis (valve
area <1.0 cm2) with a transvalvular PG <30 mmHg
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Low gradient AS occurs in LV systolic dysfunction
with low EF, which results in low flow rate across AV
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Contractile reserve: the ability to increase
transvalvular flow and not defined by an
improvement in wall motion score or EF
LF-LG AS
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Low gradient AS: a) caused by critical AS causing LV
impairment (fibrosis)
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b) moderate AS coexisting with another cause of LV
impairment: CAD, alcohol, cardiomyopathy
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The main challenges:
- to differentiate these two states
- to determine whether the LV is likely to recover after
AV surgery
Epidemiology
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Difficulty to assess true severity of stenosis at low CO
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PG & calculated AVA flow-dependent
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LV dysfunction: Presence of low flow rather than
significant valve disease
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Morbidity & Mortality LG AS + low EF, A. surgery is consid
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50% do not survive or post op persistent symptoms
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> 600 AS, pts. >125 mmHg = best postop. survival, pts
MPG <35 mmHg had worst (Lund, Circulation)
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The risk is increased with CAD
DOBUTAMIN STRESS ECHO TEST
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Assess aortic stenosis with poor LV function
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Generally low gradient and low area with low dose D
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Increase in gradient: significant AS
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increase in aortic valve area: poor hemodynamics
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non-significant AS
Continuous infusion up to 20mcg/kg/min
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DOBUTAMIN STRESS ECHO
..
To differentiate between:
True vs Pseudo-severe AS
SEVERE AS
. AV area remains almost the same after test
. PG. MPG & PVsignificantly 
MILD TO MODERATE AS
All parameters 
Pseudo-severe AS:
. AVA significantly  (0,3cm2)
. PG, MPG, PV remain more or less
constant despite flow improvement
INDICATIONS FOR DSE
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In symptomatic patient with AS where
echocardiography findings during the rest
do not correlate with the symptoms.
DSE
DSE
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Fixed low-gradient AS: benefit from valve
replacement surgery
pseudo-AS : valve replacement surgery is
not indicated
Patients and Method
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A male 62 y/o, at least moderate AS with low
flow and low TG
72 kg, 172cm, BSA 1,86cm2,
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DST starting: 2,5mcg/kg/min increasing at 3
min.intervals to 5, 10, 15 and 20 mcg/kg/min
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Monitoring: 12-lead ECG, RR
Results
At rest
- LV: normal sized
- Akinesis: apical anteroseptal, inferoapical,
posterorolateral, mid segment of anteroseptal
- Hypokinesis: basal and mid posterior, inferior
and lateral
- EF : 33%
- PG: 55mmHg, MPG: 35mmHg
- EOA: 0,8cm2. (0,4cm2/cm2)
At Peak:
Contractility improved in: basal, mid lateral
segment
decreased in: basal segment of anterior
septum
. The other LV wall segments: no change after the
test
. EF ↑ up to 40%
. PG ↑ 64mmHg, MPG 46mmHg
RESULTS
Final diagnosis:
Severe aortic stenosis with
preserved contractile reserve
DECISION
Surgical Valve Replacement
CONCLUSION
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Dobutamin Stress Echocardiography:
- Relevant Dg info in AS of unclear
significance & reduced LV function
- Better outcome if management decisions
based on the result of DST
- Moderate AS after DSE: conservative th.
THANK YOU !