1. Assessment of Operability in CHD with PAH
Krishna Kumar
Amrita Institute of Medical Sciences and Research Center
Cochin
Kerala, India

2. Congenital Heart Disease
Surgery for PDA
Paul Wood: Eisenmenger syndrome,
Open heart surgery for common shunts
Early Open Heart surgery in Infants
Infant open heart surgery widely established in developed countries
Infant open heart surgery in selected parts of the developing world
100%
Developed world
Percentage of infants with large VSD receiving timely surgery
Developing world

3. Pulmonary Vascular Obstructive Disease
Definition:
 PVR in CHD (Qp)
Precludes safe closure
PAp high after closure; may further 
Timely CHD correction: prevents (but not eliminates)
Common in developing world

4. Estimated proportion of infants with critical CHD undergoing surgery within the first year of life in India
Number undergoing surgery in the first year of life
Estimated number of infants with critical CHD
2012

5. CHD Services in Selected Asian Countries
Sources: 1: Children’s HeartLink, 2: Dr. Sukman Putra, 3. Dr. Masood Sadiq ,4. Dr. Euneil Solinap, 5. Dr. Duminda Samarasinghe

6. Parts of The World Where the Average Child in the Region has Access to Congenital Heart Surgery

7. Deciding operability of L-R shunts
Clinical evaluation
Chest X-ray and ECG
Measurement of oxygen saturation
Echocardiography
MRI
Cardiac catheterization

8. Agenda
Basic concepts
How do we decide on operability of L-R shunts today?
What are the indications to perform catheterization?
What are the limitations of the tools that we have with us?

9. What determines the development of pulmonary vascular obstructive disease?
Pre vs. post tricuspid
Size
Associated lesions: pulmonary venous hypertension
Lungs and airways obstruction
Altitude
Syndromes: Tri-21
Anatomy of defect
Associated conditions
Time
Unknown influences *
Genetic???

10. Conceptual framework:
Pre-tricuspid shunts: gradual increase in Qp as RV accommodates and enlarges – ASD, PAPVC, TAPVC*
Post tricuspid shunts: Direct transmission of pressure head: VSD (systolic), PDA, AP-Window (systolic and diastolic)

11. Conceptual framework:
Pulmonary venous hypertension, associated mitral stenosis, other forms of LV inflow obstruction:
May introduce a substantial element of reversibility
May protect pulmonary vasculature from the effects of increased pulmonary blood flow???

12. Conceptual framework:
Hypoxia elevates pulmonary vascular resistance
Diseases of pulmonary parenchyma
Airways (upper and lower)
Hypoventilation
High altitude

13. Conceptual framework:
Time
The likelihood of development of PVOD increases with time
The rate of increase in PVR varies depending on a number of influences

14. Defect vs. PVOD Risk 100% TGA VSD/PDA Unrestrictive VSD or PDA
Large Fossa ovalis ASD
Truncus
SV ASD
Likelihood of operability
Age
Early childhood
Infancy
Adolescence
Adulthood

15. Risk of development of PVOD: Other (unknown) influences
Remarkable individual variability
ASD with severe PAH in a child
VSD with shunt reversal in an infant
Operable AP window in a teenager
Operable large VSD in an adult
Prediction for an individual patient is sometimes quite challenging

16. Other (?Genetic) Influences
Least
Most
IPAH??
Risk of PVOD

17. What principles govern decision on operability?
Post tricuspid shunts: Generally operable if there is evidence of a significant shunt in the basal state irrespective of PA pressure
Pre-tricuspid shunts: Pulmonary hypertension (anything more than mild) warrants concern especially if basal shunt is not obvious

18. Deciding operability: Principles
Age is an important variable and benefit of doubt must be given to younger patients.
E.g. a 1 year old with VSD and severe PAH where basal shunt is not obvious
Lung, airway and ventilation issues can elevate PVR and confound assessment
Pulmonary venous hypertension can result in reversible elevations in PVR

19. Congenital Heart Disease (L-R shunts) and Pulmonary Hypertension
Maurice Beghetti, and Nazzareno Gali, J. Am. Coll. Cardiol. 2009;53;

21. Clinical Spectrum of PAH in CHD
Operable
Clear evidence of a large L-R shunt
Typically younger patients
Borderline situation: PVR elevated ; operability uncertain.
Inoperable: Eisenmenger physiology
Shunt reversal
Typically older patients

23. Clearly Operable: Cath not requiredLV RV LA LV RA RV
Clearly Operable: Cath not required

24. 26 year old
Blue
Single loud S2

25. Clearly Inoperable: Cath not requiredRV LV RA LA
Clearly Inoperable: Cath not required

26. Clinical spectrum of post-tricuspid shunts with PAH
Operable
Failure to thrive,  precordial activity, mid diastolic murmur at apex,
Cardiac enlargement, pulmonary blood flow
Q in lateral leads on ECG, good LV forces
LA/LV enlargement, exclusively L-R flows across the defect
Clear clinical /noninvasive evidence of a large left – right shunt
Borderline clinical non-invasive data: uncertain operability
Cyanosis, quiet precordium, no MDM
Normal heart size, peripheral pruning
No Q in lateral leads, predominent RV forces
No LA LV enlargement, significant R-L flows across the defect
Clear evidence of shunt reversal resulting from high PVR.
Inoperable

27. Another Example…… 10 yr old boy
Detected to have congenital heart disease in early infancy but did not undergo surgery.
Asymptomatic except for an occasional respiratory infection

28. Evaluation Normal Growth & Development. Pulse: 88/min, BP: 104/70mmHg
SPO2: 100%
CVS:
S1 normal .S2 split normally. A2=P2
Harsh ESM at LUSB. S3+.
RS: B/L Clear.
No hepatomegaly.

30. ECG
75/min. P axis 60deg, QRS axis: 75deg. No e/o atrial enlargement
R/S: V1=25/5, V6=35/20. tiny q waves in V6

31. ECHO

33. Cath Data (Room Air) Dias(a) Mean O2 % SVC 3 6 2 74.7 RA PA 105 46 75
Chamber
Sys(v)
Dias(a)
Mean
O2 %
SVC 3 6 2
74.7 RA PA
105 46 75 85
PA wedge 5 PV
98 (a) RV
120
ED= 4 Ao
114 54 77
94.3
PV was not entered. Saturation was assumed
Oxygen consumption was assumed

34. Parameter
Condition 1
( room air)
O2 Consumption
156 ml/m2 Qp
6.01 Qs
4.47
Qep
3.5
Qp/Qs
1.34
PVRI
11.82
SVRI
16.78
L-R shunt
2.51

35. Decision Has cath data helped to make a decision
Is he suitable for VSD closure?
Do we significantly alter his natural history by intervention?
Should we test with pulmonary vasodilators?

36. FLOW AND RESISTANCE CALCULATIONS
Parameter
Condition 1
( room air)
Condition 2
(FiO2 100)
Condition 3
(NO 40PPM + O2)
O2 Consumption
156
152 Qp
6.01
8.66
8.9 Qs
4.47
4.05
3.68
Qep
3.5
Qp/Qs
1.34
2.14
PVRI
11.82
7.5
6.74
SVRI
16.78
19.25
18.2

37. Our Management Plan The family was counseled
Underwent fenestrated VSD closure + PDA ligation

38. Post op course Uneventful PA pressure 1/3 to ½ systemic
Extubated by day 2
Echo at discharge:
Fenestration L->R
IVG: 60mmHg
Discharged on PDE5 inhibitors

39. Small Fenestration in VSD patch L->R Mild TR. RVSP 65+ RA.
Follow Up Echo
Small Fenestration in VSD patch L->R
Mild TR. RVSP 65+ RA.

40. CATH Data (On Sildenafil, 1 year later)
Chamber
Sys(v)
Dias(a)
Mean
O2 %
PO2
SVC
79.8
45.9 RA 2 PA 66 30 50
82.7
48.2 PV
99(a)
PA wedge 5 LV
120
ED 6 Ao
118 78 98
97.7
93.4
PVRI: 7.96 WU; PVR/SVR ratio: 0.4

41. Ideally….. Cath Operable Operable Operable Borderline Inoperable

42. PVR Estimation by Cardiac Catheterization
Pulmonary artery mean pressure
Pulmonary venous mean pressure
Trans-pulmonary gradient
PVR =
Pulmonary blood flow
Oxygen consumption
PVO2 content
PA O2 Content

43. Sources of Error / Limitations in Catheterization Data
Assumed oxygen saturations
Assumed pulmonary vein saturation
“Non-physiologic” state
Calculated PVRI (basal and post-pulmonary vasodilator) has not been adequately standardized against the gold standard “surgical outcome”

44. In the Real World…… Operable Inoperable Borderline Operable Inoperable

45. Cath criteria (Baseline Room Air)
Favorable
Unfavorable
PVRI (Wood U)
<6 (Ideally < 4)
>8
PVR/SVR ratio
<0.3
>0.5
Positive vasodilator: > 20% fall in PVR
Lopes et al Pulmonary Circulation 2013

46. Indication for Cath in ASD
Clinical clues may be less obvious than VSD or PDA
Echo evidence of elevated PA pressure (RVSP > mm Hg: Suggests need for cath
Clear evidence of flow reversal (sats < 90%) suggestive of  PVR do not require cardiac cath

47. Indications for Cardiac Cath: Data From Amrita Institute: 1998-2001

48. Interventricular and Transductal velocity by Doppler
Clear understanding of the hemodynamics
Comprehensive clinical assessment
Influenced by the pulmonary artery and aortic pressures at the time of examination
Proper alignment is essential
Left parasternal view or high parasternal view for ductus; no ‘best’ view for VSD
Record peak systolic and end diastolic gradients in PDA

49. Deciding operability of L-R shunts
Clinical evaluation
Chest X-ray and ECG
Measurement of oxygen saturation
Echocardiography
Resting and post exercise ABG (PO2)
Cardiac catheterization
?MRI
Viswanathan S, Kumar RK, Assessment of operability in congenital cardiac shunts with increased pulmonary vascular resistance, Cathet Cardiovasc Interv. 2008; 71:665-70

50. What else can be done in the cath lab?
Test occlusion of the defects:
ASD
PDA
Little validation with long term data
Immediate reduction of PA pressure may not translate into long term benefits

51. Illustrative Example 16 year old boy, 9.4 mm duct
Nearly systemic PA pressures (Ao 120/60, mean: 90; PA 110/60: mean: 80)
LL O2 Saturation: 96%
Qp/Qs: 1.15:1 (Qp 3.8; Qs: 3.3)
Basal PVRI: Wood Units; PVRI/SVRI ratio: 0.66

52. Illustrative Example
Balloon Occlusion PA Ao

53. Illustrative Example 5 minutes after balloon occlusion Ao: 125/77 (96)
PA: 66/18 (41)

54. Conclusions
Comprehensive clinical evaluation supplemented by echocardiography:
Allows adequate hemodynamic assessment of for decision making in > 95% of patients with L-R shunts.
Cardiac cath and pulmonary vasodilator testing is often done for borderline situations ?uncertain incremental value
Some exceptions: Test occlusion of PDA

55. VSD: Case 1 8 months old boy
6mm perimembranous VSD, partly covered by STL
IVG 60mmHg
CFM: turbulent jet across the VSD
Mild LA, LV dilatation

56. VSD: Case 2 3 year old girl 7 mm perimembranous VSD IVG 10mmHg
CFM: Nonturbulent flow across the VSD, transient right to left flow in diastole
LA, LV dilatation

57. VSD: Case 3 8 months old girl 2mm perimembranous VSD IVG 10mmHg
CFM: Nonturbulent flow across the VSD

58. VSD: Case 4 1.5 year old, Intracardiac repair done for TOF
Weaning from ventilator not possible
Echo: 3mm residual VSD, IVG 70mmHg, IVS motion paradoxical, mild LA and LV dilatation
Cath: RVSP 70mmHg, LVSP 90mmHg, Qp:Qs 2.2

59. PA Pressure Estimation: Ideal Situation
Ideally, the peak instantaneous gradient measured by Doppler in VSD should be quite similar to the peak-peak gradient by cath.
Peak-peak (cath)
Peak instantaneous (Doppler)

60. PA Pressure Overestimation by Doppler Because of Change in Slope of the RV Pressure Upstroke
If the slope (dp/dt) of the RV systolic pressure trace is slowed (green) because of RBBB or RV dysfunction there can be a significant difference in Doppler vs. cath gradients and Doppler may underestimate PA pressures
Peak-peak (cath)
Peak instantaneous (Doppler)

61. In the presence of RBBB or RV dysfunction, IV doppler gradient is unreliable in predicting RVSP/size of the VSD

62. PDA: Case 1 “2mm” PDA Systolic PG 80, Diastolic PG 50
PA pressure 25/15,
Ao 110/70

63. PDA: Case 2 “2.5mm” PDA Systolic PG 80, Diastolic PG 30
PA pressure 25/15,
Ao 110/50

64. PDA: Case 3 “3mm” PDA SPG 60, DPG 20 PA pressure 60/20, Ao 120/40
An anxious patient or unsedated child will have systolic hypertension and would record high systolic PG even with a relatively large PDA
Low (30mmHg) Diastolic gradient predicts significant flow and hence a larger duct

65. PDA: Case 4 5mm PDA PA pressure 110/30, Ao 120/38 SPG 10, DPG 8
“Large but short duct”

66. Transductal velocity
Large ‘short’ duct: Aortic pressure gets transmitted directly, can have near systemic or systemic pulmonary pressures. Systolic PG also would be small.
Corollary: Small systolic PG may suggest shallow ampulla
Large ‘long’ duct: Length of the duct offers resistance, no direct transmission of aortic pressure. Hence systolic PG would be moderately high

67. Flow Reversal in the Abdominal Aorta

68. Transductal velocity
If DPG is recorded high, ductus is usually small, probably 2D echo is missing the narrowest PA end
Patients with pulmonary vascular disease: small PG or bi-directional flow; duct has to be large
Small PG or bi-directional flow but ductus size is small by 2D: Patients with high PVR due to other causes e.g. pneumonia. Corollary: Small gradient does not automatically mean a large duct.