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

Assessment of Operability in CHD with PAH

Krishna KumarAmrita Institute of Medical Sciences and Research Center

CochinKerala, India

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

1940 1950 1960 1970 1980 1990 2000

0

100%

Percentage of infants with large VSD receiving timely surgery

Developed world

Developing world

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

Estimated proportion of infants with critical CHD undergoing surgery within the first year of life in India

Estimated number of infants with critical CHD

Number undergoing surgery in the first year of life

2012

Deciding operability of L-R shunts

• Clinical evaluation• Chest X-ray and ECG• Measurement of oxygen saturation• Echocardiography• MRI• Cardiac catheterization

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?

What determines the development of What determines the development of pulmonary vascular obstructive disease?pulmonary vascular obstructive disease?

Anatomy of defect

Time

Pre vs. post tricuspidSize

Associated lesions: pulmonary venous

hypertension

Lungs and airways obstructionAltitudeSyndromes: Tri-21

Genetic???

*

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)

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???

Conceptual framework:

Hypoxia elevates pulmonary vascular resistance • Diseases of pulmonary parenchyma• Airways (upper and lower)• Hypoventilation• High altitude

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

Large Fossa ovalis ASD

SV ASD

Unrestrictive VSD or PDA

TruncusTGA VSD/PDA

100%Li

kelih

ood

of o

pera

bilit

y

Age

Infancy Early childhood

Adolescence Adulthood

Defect vs. PVOD Risk

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 adultPrediction for an individual patient is sometimes

quite challenging

Other (?Genetic) Influences

N

Risk of PVOD

Least Most IPAH??

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

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

Congenital Heart Disease (L-R shunts) and Pulmonary Hypertension

Maurice Beghetti, and Nazzareno Gali, J. Am. Coll. Cardiol. 2009;53;733-740

Clinical Spectrum of PAH in CHD

• Clear evidence of a large L-R shunt

• Typically younger patients

Operable

Inoperable: Eisenmenger physiology

• Shunt reversal

• Typically older patients

Borderline situation: PVR elevated ; operability uncertain.

LV

RVLA

LV

RA

RV

Clearly Operable: Cath not required

26 year old

Blue

Single loud S2

Clearly Inoperable: Cath not required

RVLV

RALA

Clinical spectrum of post-tricuspid shunts with PAH

Clear clinical /noninvasive evidence of a large left – right shunt

Operable

Clear evidence of shunt reversal resulting from high PVR.

•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

Inoperable

•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

Borderline clinical non-invasive data: uncertain operability

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

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.

ECG

SR @ 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

ECHO

Cath Data (Room Air)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

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

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?

FLOW AND RESISTANCE CALCULATIONS

Parameter Condition 1

( room air)

Condition 2

(FiO2 100)

Condition 3

(NO 40PPM + O2)

O2 Consumption 156 152 152

Qp 6.01 8.66 8.9

Qs 4.47 4.05 3.68

Qep 3.5 4.05 3.68

Qp/Qs 1.34 2.14 2.14

PVRI 11.82 7.5 6.74

SVRI 16.78 19.25 18.2

Our Management Plan

• The family was counseled• Underwent fenestrated VSD closure + PDA

ligation

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

Follow Up Echo

Small Fenestration in VSD patch L->R

Mild TR. RVSP 65+ RA.

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

Cath

Operable

Inoperable

Operable

Inoperable

Ideally…..

Borderline

Operable

Inoperable

PVR Estimation by Cardiac Catheterization

Pulmonary artery mean pressure

Pulmonary venous mean pressure

Trans-pulmonary gradientPVR =

Pulmonary blood flow

Oxygen consumption

PVO2 content PA O2 Content

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”

AIMS, Kochi

Limitations of Echo for CHD

Operable

Inoperable

Borderline

Operable

Inoperable

Borderline

In the Real World……

Inoperable

Borderline

Operable

AIMS, Kochi

Limitations of Echo for CHD

Favorable Unfavorable

PVRI (Wood U) <6 (Ideally < 4) >8

PVR/SVR ratio <0.3 >0.5

Cath criteria (Baseline Room Air)

Positive vasodilator: > 20% fall in PVR

Lopes et al Pulmonary Circulation 2013

Indication for Cath in ASD

• Clinical clues may be less obvious than VSD or PDA

• Echo evidence of elevated PA pressure (RVSP > 50-60 mm Hg: Suggests need for cath

• Clear evidence of flow reversal (sats < 90%) suggestive of PVR do not require cardiac cath

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

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

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: 18.75 Wood Units;

PVRI/SVRI ratio: 0.66

Illustrative Example

PAAo

Balloon Occlusion

Illustrative Example

Ao: 125/77 (96)PA: 66/18 (41)

5 minutes after balloon occlusion

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