1. Echocardiographic assessment of Patent Ductus Arteriosus
Dr Sandeep Mohanan
Senior resident, Cardiology
GMC, Kozhikode

2. TOPIC OVERVIEW PDA anatomy and classification
Echocardiographic identification
Echocardiographic quantification
Role of Echo in corrective management
Role of 3D Echo and TEE

3. Anatomy ~ 10 * 5mm 5-10mm from the L-SCA
Connects to the LPA-MPA junction( actually embryologically from the distal 6th left arch (proximal of which forms the proximal LPA)
Around 5-10mm distal to the LSCA origin.
At birth it has a diameter of ~ 10mm and in newborn it is almost as if a continuation from the MPA
It runs parallel to the arch in same direction and joins at an angle of 30-35degree..... In an AP projection the PDA actually overlaps its aortic entrance

4. Embryology
Distal part of Left 6th arch

5. Classification – Angiographic (Krichenko et al,1989)
Conical
Window- like
Elongated with a remote constriction
Tubular
Complex with multiple constrictions
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):

6. Why the PDA is often difficult to Echo-image?
TTE??
TEE??

7. 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

8. 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

9. TTE-PSAX view for PDA
Start in the high parasternal view...initially angle slightly to the right where the ascending aorta is visualized and RPA crosssection posteriorly...then slightly keep rotating probe to left till the MPA a body is seen...A further slighter angulation foreshortens the MPA and body and brings a good view of the bifurcation.... This reveals the root of the LPA and the origin of the PDA... In this view the PDA is seen to arise superiorly from the LPA root as an arch that is in continuity with the MPA

10. 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

11. 2. Horizontal short axis view

12. 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.

13. Doppler echo

14. CWD - Normal PA vs PDA

15. 3. Ductal view – high parasternal sagittal view

16. Ductal view with colour Doppler

17. Echo measurement of the Pulmonary end

18. 4. TTE- Suprasternal view

19. 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 

20. PDA type characterisation by suprasternal view

21. Measurements from the suprasternal view
-Ampulla
Adjacent aortic
diameter.
For the purpose of device sizing it is important to assess aortic size...so as to avoid luminal encroachment.

22. PDA significance The direction of shunting The shunt gradient
PA pressures
Size of the PDA

23. Direction of predominant shunting -PWD

24. 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.

25. 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

26. PDA with suprasystemic pressures

27. PDA shunt quantifcation
LA/ Aorta ratio -- >1.5 – moderate to large PDA
(Sens -79%, Spec-95%)1
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

28. 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)

29. Qp/Qs in PDA Thus, Qp/Qs = LV output / RV output
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

30. 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

31. Diastolic flow reversal in Descending Ao
PWD in PDA
NORMAL FLOW
Retrograde diastolic flow –VTId/VTIs >30% ~ QP/Qs>1.6

32. Increased diastolic flow in branch PAs

33. PDA in a Right aortic arch
The PDA is commonly left in origin

34. 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

36. Infective endocarditis
TEE image showing vegetations on the MPA wall at the pulmonary end of PDA

37. Use of 2D Echo in pre-interventional work up
Minimum diameter (A)
Length (B)
Ampulla diameter (C)
PDA type

38. 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:

39. Important to define the Ampulla
Adequate Ampulla: Length of PDA> Narrowest portion of the PDA
(usually at pulm end)

40. Inadequate ampulla: Short PDA
- Worst example : WINDOW type (Type B)

41. Tubular ductus: Same diameter from aorta to pulmonary end

42. Echo classification
CONICAL DUCT ( common)
WINDOW DUCT
TUBULAR DUCT

43. 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 – 27 children...difference of upto 1.7mm in assessing minimum diameter, Colour doppler excluded 11% patients on the premise that it was large (>4mm)...angiographically <4mm
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.
Comprehensive Assessment of Patent Ductus Arteriosus by Echocardiography Before
Transcatheter Closure. J Am Soc Echocardiogr 2002;15:

44. 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

45. 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

46. Doppler TEE of PDA
Evaluation of Shunt Flow by Multiplane Transesophageal Echocardiography in Adult
Patients with Isolated Patent Ductus Arteriosus. JASE 2002.

47. 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:

48. 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

49. 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

50. 3D TEE

51. 3D TEE cropped view from aortic side

52. 3D TEE guided device occlusion

53. 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.

54. THANK YOU