Transcript Echocardiographic assessment of Patent Ductus Arteriosus

Echocardiographic assessment of
Patent Ductus Arteriosus
Dr Sandeep Mohanan
Senior resident, Cardiology
GMC, Kozhikode
TOPIC OVERVIEW
• PDA anatomy and classification
• Echocardiographic identification
• Echocardiographic quantification
• Role of Echo in corrective management
• Role of 3D Echo and TEE
Anatomy
~ 10 * 5mm
5-10mm from the L-SCA
Embryology
Distal part of Left
6th arch
Classification – Angiographic
(Krichenko et al,1989)
Conical
Window- like
Tubular
Complex with multiple constrictions
Elongated with a remote
constriction
Krichenko et al. Angiographic classification of the isolated, persistently patent ductus arteriosus and implications for
percutaneous catheter occlusion. Am J Cardiol.1989 Apr 1;63(12):877-80.
Why the PDA is often difficult to Echo-image?
TTE??
TEE??
When should the echocardiographer
look for a PDA?
• All neonatal echo s
• All paediatric referral for Echo
• Any unexplainable cause of heart failure in
adults
• Unexplained central cyanosis
• Any unexplained PAH, LV volume overload
• Any referral for suspicion of IE
TTE- PSAX view
The 1st step in imaging the ductus is knowing where to look for it.
Superior and leftward
sweep of a routine
Basal PSAX view
TTE-PSAX view for PDA
1. Three-legged pant view
-high left PSAX view
A large PDA shunting L to R is often easily visualized
However smaller PDA required help of Colour Doppler
2. Horizontal short axis view
PSAX – Colour Doppler Echo
-Identify the ‘central
flame in the blue stream’
(red - PDA
blue-LPA, RPA, Desc Ao)
- A flow that appears to
come from the left
corner of the LPA origin
and directed usually
towards the left PV
However again confusion arises in the case of a predominant R to L shunt through the PDA.
Doppler echo
CWD - Normal PA vs PDA
3. Ductal view
– high parasternal sagittal view
Ductal view with colour Doppler
Echo measurement of the Pulmonary end
4. TTE- Suprasternal view
The value of suprasternal view above
parasternal views
Zhang et al. Value of the Echocardiographic Suprasternal View for Diagnosis of Patent Ductus
Arteriosus Subtypes. JUM September 1, 2012vol. 31 no. 9 1421-1427
PDA type characterisation by
suprasternal view
Measurements from the suprasternal view
-Ampulla
-Adjacent aortic
diameter.
PDA significance
• The direction of shunting
• The shunt gradient
• PA pressures
• Size of the PDA
Direction of predominant shunting
-PWD
Increasing PA pressures
Appearance of an early systolic R to L shunt with
increasing PA pressures
Widening and deepening of
early systolic R to L shunt in parallel
with a lesser L to R gradient.
PDA-Eisenmenger
• Very difficult to demonstrate the Doppler flow
• Corroborative evidence and clinical picture should guide
suspicion : Septal flattening, RVH, dilated PA, high velocity
PR etc
• Contrast Echo : reveal bubbles in the descending aorta and
not in the ascending aorta
PDA with suprasystemic pressures
PDA shunt quantifcation
• LA/ Aorta ratio -- >1.5 – moderate to large PDA
(Sens -79%, Spec-95%)1
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LV dimensions
LV output
Qp/Qs
PDA pressure gradient
Colour Doppler ductal diameter
Diastolic flow reversal in descending aorta
1. Re-evaluation of the left atrial to aortic root ratio as a marker of patent ductus arteriosus.
Archives of Disease in Childhood 1994; 70: Fl 12-Fl 17
Qp/Qs in PDA vs ASD/VSD
• In VSD Qs- Qp = shunt
• In ASD Qs - Qp = shunt
Any output from LV goes to the systemic circulation ...
So, Qs= LV output
Any output from RV goes only to pulm circulation
ie, Qp = RV output
So Qp/Qs = RV output/ LV output for ASD & VSD
--- Continuity equation )
• However in PDA the shunt is extracardiac
Therefore, Qp ≠ RV output (will be more) and Qs ≠ Lv output (will be
less)
Qp/Qs in PDA
• Counterintuitively ,Qs = RV output & Qp = LV output
• Thus, Qp/Qs = LV output / RV output
..... FOR AN ISOLATED PDA
However, for most neonates this is unusual.
Coexisting L to R shunts makes simple ventricular output
ratios unreliable
Colour Doppler ductal diameter
• Optimal gain settings
(not too high)
•Maximum Doppler
scale settings
• Duct should be
imaged
along its entire length
Colour Doppler diameter > 2mm ~ Qp/Qs >2:1 in neonates
Evans N, Iyer P. Assessment of ductus arteriosus shunt in preterm infants supported by mechanical ventilation: effect of interatrial shunting.
J Pediatr.1994;125:778–785
Diastolic flow reversal in Descending Ao
PWD
NORMAL
in PDA
FLOW
Retrograde diastolic flow –VTId/VTIs >30% ~ QP/Qs>1.6
Increased diastolic flow in branch PAs
PDA in a Right aortic arch
• The PDA is commonly left in origin
Ductal aneurysm
• ~8%
• May present at any age
• In adults may present as a thoracic mass or with
cardiovocal syndrome
• In children may spontaneously resolve
• Requires surgical excision / covered stent
placement
Infective endocarditis
TEE image showing vegetations on the MPA wall at the pulmonary end of PDA
Use of 2D Echo in pre-interventional
work up
• Minimum diameter (A)
• Length (B)
• Ampulla diameter (C)
• PDA type
Use of 2D Echo in pre-interventional
work up
• Echo classification corresponding to Krichenko’s
A- Conical with a narrow pulmonary end
B- Short with narrow aortic end
C- Tubular without constriction
D- Multiple constrictions
E- Long and tortuous requiring >1
echo plane for complete imaging
Comprehensive Assessment of Patent Ductus Arteriosus by Echocardiography Before
Transcatheter Closure. J Am Soc Echocardiogr 2002;15:1154-9.
Important to define the Ampulla
• Adequate Ampulla: Length of PDA> Narrowest
portion of the PDA
(usually at pulm end)
• Inadequate ampulla: Short PDA
- Worst example : WINDOW type (Type B)
• Tubular ductus: Same diameter from aorta to
pulmonary end
Echo classification
• CONICAL DUCT ( common)
• WINDOW DUCT
• TUBULAR DUCT
Correlation of 2D echo and Angio
• Wong et al found poor correlation between colour
Doppler and angiographic measurements1
• 2DE imaging overestimates the minimal diameter in
comparison with angiography but in the majority
difference was <1mm2
• In ~14% there is discrepancy in classification type2
• Ampulla and length measurement were the most
discordant
1. Wong et al. Validation of color Doppler measurements of minimum patent ductus arteriosus
diameters: significance for coil embolization. Am Heart J 1998;136:714-7.
2. Comprehensive Assessment of Patent Ductus Arteriosus by Echocardiography Before
Transcatheter Closure. J Am Soc Echocardiogr 2002;15:1154-9.
TEE for PDA
• TEE is not that popular among the PDA cohort in
its incremental benefit in echo diangnosis,
compared to ASD, VSD and complex congenital
heart disease
• Inherent difficulties in imaging
TEE imaging
-In high esophageal position (~20-35cm), probe rotated completely backward to image
decending aorta in the short axis (0 deg)....
-Then slowly rotated to around 60 to 80 deg will help visualize the PDA to PA connection
Doppler TEE of PDA
Evaluation of Shunt Flow by Multiplane Transesophageal Echocardiography in Adult
Patients with Isolated Patent Ductus Arteriosus. JASE 2002.
TEE vs TTE
• 40 patients with PDA
• Gold standard--- angiography
TEE sensitivity –97% vs 42%
and
TEE NPV 98% vs 68%, ;
p<0.001) for confirming the
presence of PDA
For PDA Eisenmenger's
syndrome, the sensitivity of
TEE in confirming diagnosis
of PDA was 100% vs 12%
(p<0.01),
Diagnostic Accuracy of Transesophageal Echocardiography for Detecting Patent Ductus Arteriosus in
Adolescents and Adults. CHEST 1995; 108:1201-05
3D echo for PDA
Full volume 3D acquisition from a modified parasternal short-axis view, cropped so as to show the
entrance of the PDA into the left pulmonary artery
3D vs 2D echo for PDA
• 42 patients with PDA (mean ~3 years)
- 3D was better than 2D for type, length,
ampulla as well as constrictions
- Both 2D & 3 D Echo overestimated Type A
- Type C was overdiagnosed by Echo
- Type D is poorly defined in echo
- Both underestimated Type E
Roushdy et al. Visualization of patent ductus arteriosus using real-time three-dimensional
echocardiogram: Comparative study with 2D echocardiogram and angiography. J Saudi Heart
Assoc 2012;24:177–186
3D TEE
3D TEE cropped view from aortic side
3D TEE guided device occlusion
Device closure guided by transaortic
phased-array imaging
Bartel et al. Device closure of patent ductus arteriosus: optimal guidance by transaortic phased-array
imaging. Eur J Echocardiogr (2011) 12 (2):E9.
THANK YOU