Pediatric Cardiac Anesthesia 2: Complex Shunts

Intensive Review of Pediatric Anesthesia 2015

Pediatric Cardiac Anesthesia 2: Complex Shunts

Susan R Staudt, MD, MSEd With co-authorship attribution to

Dean Andropoulos, MD & Emad B Mossad, MD


Learning Objectives

• Follows/builds on simple shunts (Dr. Mossad) • Review complex shunts and mixing lesions: Truncus

Arteriosus, d-TGA, TAPVR • Discuss Single ventricle lesion types • Refresh knowledge of anatomy and physiology of the

3 stages of single ventricle palliation • Examine remaining miscellaneous cardiac and

extracardiac congenital heart defects • NOTE: NO DISCLOSURES or COI


Incidence/Prevalence of Congenital Heart Disease

• 8 per 1000 infants in the U.S. are born with CHD – Most common birth defect requiring treatment – 32,000 neonates annually; 8-9000 surgeries

• Survival now >95% for CHD surgery – ≈30,000 CHD surgeries annually in US: 25,000 <18yrs; 5,000 >18 yrs

• ≈ 1 million children with CHD • > 1 million adults with CHD—1 in 150

– 55% simple lesions: ASD, VSD most common – 30% moderately complex: TOF most common – 15% complex lesions: TGA, single ventricle lesions

Circulation 2013;127:e153 4


Incidence of Common CHDz Lesions in Children • Ventricular septal defect: 20.1% • Atrial septal defect: 16.8% • Valvar pulmonic stenosis: 12.6% • Patent ductus arteriosus: 12.4% • Tetralogy of fallot: 7% • Coarctation of aorta: 6.8% • Valvar aortic stenosis: 5.5% • Atrioventricular septal defects: 3.9% • Transposition of the great vessels: 3.6% • Other (11.3% )

Circulation 2012;125:e97 5


VSD 15.4 15.7 31 5

AoCoA 10.5 7.5 5.6 11

Transposition (TGA) 10.4 9.9 4.5 2

Tetralogy of Fallot 9.9 8.9 5.5 3

Patent Ductus Arteriosus 6.7 6.1 7.1 -

AV canal 3.9 5.0 4.4 17.5

ASD 0.5 3.0 7.5 -

Hypoplastic Left Heart (HLHS) 3.7 7.4 3.1 16

Single ventricle, other >10% 4.3 2.4 1.5 2

Tricuspid atresia (HRHS) 4.7 2.6 2.4 4

Pulmonary Stenosis 3.0 3.3 7.0 5

Truncus Arteriosus 2.1 1.4 1.4 1.5

Pulmonary Atresia 1.9 3.1 1 -

TAPVC (total anomalous pulm vein connection) 3.6 2.6 1.4 1

Double outlet Rt Venticle 3.0 1.5 1.2 3

Ebstein’s Anomaly 0 1 1 7

4 Recent Reports Relative Incidence CHDz lesions presenting for surgical repair…

Adapted from Table 16-3 COTE et al.

Conclusions: Most common Surgically repaired lesions: VSD+CoA+TGA+TOF+ HLHS/SV +PDA = > 63% lesions (include asd and av canal =75%)


Truncus Arteriosus • Major types are I,II,III and depend on

location/degree of PA branching • Common arterial trunk results in systemic,

pulmonary, and coronary circulations in parallel

• Lowering PVR with excessive FiO2 and hyperventilation creates systemic/coronary steal and myocardial ischemia

7


Andropoulos and Gottlieb; Congenital Heart Disease,

Anesthesia and Uncommon Diseases, 6th Ed., Fleisher L., (ed.) 2012, p. 101

Truncus Arteriosus

8

Type I Type II


Truncus Arteriosus

9 Andropoulos and Gottlieb; Congenital Heart Disease,


Type III Type IV

REPAIR: VSD Closure-- place RV-PA valved conduit and if needed build PA confluence and PA-plasty (type 4 worst outcome)


Anomalous Pulmonary Venous Return • Major types are partial (PAPVR) and total (TAPVR) • PAPVR usually has mild symptoms of small left-to-

right shunt and sinus venosus ASD • TAPVR symptomatology depends on degree of

obstruction to pulmonary venous return • Infradiaphragmatic TAPVR prone to severe

obstruction, hypoxia, respiratory failure – Increasing PBF with high FiO2 and iNO may

paradoxically worsen obstruction before repair 10


Total Anomalous Pulmonary Venous Return

11

Supracardiac Cardiac Andropoulos and Gottlieb; Congenital Heart Disease,

Anesthesia and Uncommon Diseases, 6th Ed., Fleisher L.,

(ed.) 2012, p. 103


Total Anomalous Pulmonary Venous Return



(ed.) 2012, p. 103

Infracardiac Mixed


Left-to-Right Shunt Lesions Left-Sided Obstructive Lesions

Right Sided Obstructive Lesions Transposition of the Great Arteries

Single Ventricle Lesions Miscellaneous

13


D-Transposition of the Great Arteries

14




D-Transposition of the Great Arteries

• Aorta arises from right ventricle, pulmonary artery from left ventricle , resulting in parallel circulation with “transposition physiology”

• Oxygenation depends on mixing at the atrial level (most important), PDA, or VSD (15-25%)

• Balloon atrial septostomy is often necessary in the neonatal period

15


Arterial Switch for D-TGA • Procedure of choice since mid 1980’s • Performed as neonate; CPB without DHCA • 15-25% also have VSD • Beware coronary problems after repair

– Global myocardial dysfunction – ST segment changes – Segmental wall motion abnormalities

• LV can be deconditioned – Intolerant of high preload or afterload – LAP 4-6, systolic BP 60s often desirable

16


Arterial Switch Operation




Congenitally Corrected Transposition of the Great Arteries (L-TGA)

• Ventricles are inverted, aorta arises from LV and PA from LV

• RA empties to LV, and LA to RV • Other associated anomalies include VSD and

pulmonic stenosis • Complete atrioventricular block is common in

cc-TGA (2% per year) • Right (systemic) ventricle usually fails over time

18


Congenitally Corrected Transposition of the Great Arteries (L-TGA)

19



(ed.) 2012, p. 117

Mitral valve


Double Outlet Right Ventricle

• VSD with both aorta and pulmonary artery arising completely or partially from RV

• Pathophysiology depends on degree of RVOTO • Cyanosis and TOF physiology are seen with

significant RVOTO • Acyanosis with CHF can be seen with no

RVOTO; in this case a VSD patch may be only needed surgery

20


Spectrum of DORV – Taussig Bing

REPAIR: Rastelli procedure-valved RV to PA homogaft, as patching of VSD precludes native PA from use (Also this is used in TGA with PS)




Single Ventricle Lesions Miscellaneous

22


Notes on “single ventricle lesions” • Broad Spectrum of pathology- hence a not uncommon

“type”-40%-50% of all cyanotic congenital heart disease is treated via this path!

• Classic HRHS: (tricuspid atresia, stenosis) • Classic HLHS :(mitral and/or aortic atresia, stenosis) • In addition are other lesions precluding a 2 ventricle repair:

PA/IVS, severe Ebsteins anomaly, unbalanced AV canals, double inlet LV, various “mixed lesions”

• Prognosis is better with: HRHS, more than 1 mass of ventricle, full term, no associated anomalies, absence of lung or airways disease


Single Ventricle Notes -2

Norwood /Sano/ stage 1

palliation

Hemifontan /BDG Fontan

HLHS HRHS

Ventricle-PA conduit Create Aorta from PA Ligate PDA NO V WORK REDUCTION PT CYANOTIC

Connect SVC to PA (remove V-PA conduit) UNLOADS V WORK (partially) PT CYANOTIC

Connect IVC to PA RETURNS V to NL Workload PT CAN BECOME ACYANOTIC


Tricuspid Atresia • Plate-like obstruction instead of tricuspid valve • Neonatal presentation depends on degree of

obstruction to pulmonary blood flow: – Severe: profound cyanosis when PDA closes – Mild/moderate: mild/moderate cyanosis, no CHF – None: mild or no cyanosis, CHF

• Systemic ventricle is the left ventricle – Good long term outcomes despite single ventricle

physiology

25


Tricuspid Atresia

26




Hypoplastic Left Heart Syndrome • 0.7% of CHD but one of most common neonatal

operations • Severe mitral and aortic stenosis or atresia • Very small or non-existent LV • Depends on PDA for systemic and coronary

circulation • Diagnosis: fetal echo; cyanosis at birth; acidosis,

murmur, poor peripheral perfusion • Formerly 100% fatal in first month; now 70-75%

survive long term 27


Hypoplastic Left Heart Syndrome



(ed.) 2012, p. 120 28


29


Pathophysiology: Mixing Lesions

30


Anesthesia and Uncommon Diseases, 6th

Ed., Fleisher L., (ed.) 2012, p. 78


Surgical Repairs: Norwood Stage I Palliation

• Done as neonate: PDA dependent on PGE1

• Delicate balance between systemic and pulmonary circulations – Often FiO2 0.21, PaCO2 40-50 mm Hg

• CPB with DHCA or RCP for aortic arch reconstruction

• Can also be done a hybrid procedure in cath lab – Sternotomy, PDA stent, PA banding, ASD stent

31


Classic Norwood repair or stage 1 palliation

Aortic arch reconstructed from PA, pulm valve and homograft; 3.5 mm B-T shunt placed for pulm blood flow

Shunt can over or undercirculate; can thrombose or kink; runoff aorta to pa lowers diastolic pressure; least risk of distorting PA’s and no ventricular incision

SANO modification

Same aortic arch repair; larger 5.0 mm RV-PA conduit instead of BT shunt

Requires a ventriculotomy (scars ventricle); higher diastolic pressure; ? Less risk of thrombosis, kinking and early complications?

Hybrid procedure

Off CPB- PA band placed via sternotomy and pda is stented (cath)

No CPB required; arch reconstruction occurs at 2nd stage of repair-infant left with retrograde coronary perfusion down tiny aorta until 2nd stage

HLHS-Three Different Approaches to Stage One Palliation


Surgical Repairs: Norwood Stage I Palliation

33

“Classic” Norwood Sano Modification

NEJM 2010;362:1980


Hybrid Approach for Stage I Palliation

34


Anesthesia and Uncommon Diseases, 6th Ed., Fleisher

L., (ed.) 2012, p. 121


Bidirectional Cavopulmonary Connection (Glenn, Hemifontan)

• Stage II or first palliation for essentially all single ventricle patients

• Performed at age 2-6 months, following cath, echo possibly MRI to risk stratify

• CPB, often no crossclamp unless intracardiac or aortic repair

• After repair desire transpulmonary pressure gradient of ≈ 10 mm Hg with low atrial pressure

35


Bidirectional Cavopulmonary Connection (Glenn)

36


Cardio-Cerebro-Pulmonary Circulation & Glenn SVC anastomosis

37

Andropoulos and Chang. Chapter 20: Pediatric Cardiac Intensive Care. In, Allen H. et al (eds.) Moss & Adams’ Heart

Disease…, 8th ed. p. 514.

êPaCO2èêCBFè êSVC flowèêPBFè êSaO2, CO, and DO2

Systemic ventricle

(both PVR and cerebral autoregulation of SVC flow can impact Qp)


Fontan Completion • Total cavopulmonary connection • Final palliation for any single ventricle

– Repair at 2-4 years, as the 2nd(HRHS) or 3rd (HLHS) stage • CPB with or without crossclamping • Fenestration allows “pop-off” for R-L shunting, preserving

C.O. with some arterial desaturation • CVP is driving force for C.O.: no right sided pulmonary

ventricle • Spontaneous Ventilation/Early tracheal extubation highly

desirable 38


Fontan Completion

39

Lateral Tunnel Extracardiac Andropoulos and Gottlieb;

Congenital Heart Disease, Anesthesia and Uncommon

Diseases, 6th Ed., Fleisher L., (ed.) 2012, p. 119


Fontan Ten Commandments • Age > 4 years • Sinus Rhythm • Normal systemic venous return • Normal Right Atrial volume • Mean PAP <15 mmHg • PVR <4 Wood units/m2 • PA/Aorta ratio > 0.75 • LVEF (or SVEF)>0.6 • Competent AVV • Absent PA distortion




Single Ventricle Lesions Miscellaneous Cardiac Lesions

41


Anomalous Left Coronary Artery from Pulmonary Artery

• ALCAPA results in myocardial ischemia and infarction in infants as PVR declines and coronary flow to the LV reverses

• Dilated cardiomyopathy ensues; ALCAPA must be ruled out in infants with DCM

• Maintain elevated PVR with low FiO2 and hypercapnea in unrepaired ALCAPA – Elevate PA pressure, increase L coronary pressure,

minimize steal into PA 42


Anomalous Left Coronary Artery from Pulmonary Artery

43



(ed.) 2012, p. 124

Ao

PA


Valvular Regurgitation • Aortic, mitral, pulmonic, or tricuspid regurgitation

can be isolated or component of more complex lesion

• Severe AI most problematic: low diastolic pressure causing coronary ischemia

• MR can lead to pulmonary hypertension if severe • PR and TR usually well tolerated • Hemodynamic goals: reduce afterload, maintain

preload, high-normal heart rate 44


Valvular Regurgitation

45

Severe MR From Failure of Coaptation of MV Leaflets

Andropoulos and Gottlieb; Congenital Heart Disease, Anesthesia and Uncommon Diseases, 6th Ed., Fleisher L., (ed.) 2012, p. 126


Pathophysiology: Regurgitant Lesions

46



(ed.) 2012, p. 78


Vascular Rings • Many variations; result from abnormal

regression of the developing aortic arches • Respiratory and/or GI symptoms

– Stridor, “wheezing”, dysphagia

• Double aortic arch (60%), right aortic arch with aberrant L subclavian artery are most common

• CT angio (preferred) or MRI for diagnosis 47


Symptoms-Imaging-Monitoring


Pericardial Effusion/Tamponade • Increases in intrapericardial pressure cause equalization

of diastolic pressures in all 4 cardiac chambers, resulting in tamponade physiology

• Distended neck veins, pulsus paradoxus, tachycardia, and low cardiac output result

• Induction of anesthesia with PPV can compromise ventricular filling and cause CV collapse

• Sedation, local anesthesia, needle pericardiocentesis; if GA keep SVR up; PPV destabilizing (? Avoid or ino/pressor “bridge”) -team ready to go ie tap then window

49


Echo imaging – Pulsus Paradoxus

Pediatric Cardiac Anesthesia 2: Complex Shunts

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