Pediatric Cardiac Anesthesia 3: Obstructive Lesions

Intensive Review of Pediatric Anesthesia 2015

Pediatric Cardiac Anesthesia 3: Obstructive Lesions

Emad B Mossad, MD Susan R Staudt, MD, MSEd

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Disclosures

• None • Acknowledgement:

– Dean B Andropoulos, MD MHCM (TCH/BCM)

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Learning Objectives

• Review Left sided obstructive congenital heart defects

• Discuss Right sided obstructive lesions • Evaluate perioperative management of

children with pacemakers/defibrillators

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

Right Sided Obstructive Lesions Transposition of the Great Arteries

Single Ventricle Lesions Miscellaneous

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Coarctation of the Aorta

Andropoulos and Gottlieb; Congenital Heart Disease,

Anesthesia and Uncommon Diseases, 6th Ed., Fleisher L., (ed.) 2012, p. 105 5


Coarctation of the Aorta

• Coarctation is normally an isolated narrowing at the juxtaductal region

• Symptoms vary from cardiovascular collapse in the PDA-dependent neonate, to late presentation with hypertension in the upper extremities

• Blood pressure monitoring in the right arm is essential

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Pre and Post-Ductal Coarctation


Surgical Repairs: Coarctation of Aorta • Repair by surgery when diagnosed

– Left thoracotomy without CPB; stenting in cath lab for recurrence – PGE1 may be required for ductal patency in neonates – Infants with severe coarct may have LV dysfunction

• Anesthetic considerations: – Right radial arterial line – 34-35° C for crossclamping (0.1% risk paraplegia) – Corticosteroids or heparin (100 units/kg) for some – Maintain high-normal BP during clamping – 15-25 minutes crossclamp, volume loading – Acidosis, hypotension, myocardial dysfunction – BP control: esmolol, nitroprusside

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Coarctation: End-to-End Repair


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

(ed.) 2012, p. 106

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Mitral Stenosis


Mitral Stenosis

• Congenital MS is rare as an isolated lesion • Often part of Shone Complex: multiple left sided

obstructive lesions: MS, AS, Coarctation of aorta • MS also caused by rheumatic heart disease, or

defect post-AV canal repair • Pulmonary congestion, respiratory infections,

wheezing, pulmonary hypertension – Loud, low-pitched mid-diastolic murmur

• Maintain afterload, preload, normal to slow HR, and NSR

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Aortic Stenosis

Andropoulos and Gottlieb; Congenital Heart Disease, Anesthesia and Uncommon Diseases, 6th Ed., Fleisher

L., (ed.) 2012, p. 107

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Aortic Stenosis • Aortic stenosis may be subvalvar, valvar, or

supravalvar • Hemodynamic goals are to maintain afterload,

normal to slow heart rate, maintain preload, and avoid increases in contractility

• Williams’ Syndrome (chromosome 7 elastin gene defect) often have coronary involvement out of proportion to supravalvar AS

• After AS repair, patients are often hypertensive 13


Aortic Stenosis Repairs • Critical AS in neonate treated with balloon

angioplasty • Subaortic membrane or LVOT muscle resection • Aortic valve repair done whenever possible • Mechanical valves rare in children • Cryopreserved homograft • Autograft: pulmonary valve to aortic position,

RV-PA conduit (Ross Procedure) – Ross-Konno involves enlarging subaortic area by

cutting down on ventricular septum, placing patch

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Ross Procedure

www.synapstudios.com

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Interrupted Aortic Arch


L., (ed.) 2012, p. 107 16


Interrupted Aortic Arch • Relative frequency:

– Type A: 35-40% – Type B: 50-75% – Type C: 5%

• Type B usually have DiGeorge Syndrome: – Chromosome 22q11.2 deletion, velocardiofacial

syndrome, hypocalcemia, absent thymus, T-cell immune deficiency: variable phenotype

• Most IAA have VSD and aortic stenosis 17


Hypertrophic Cardiomyopathy • Increase in LV muscle mass resulting in LVOTO • Genetic and familial causes • Hypertrophied septum and systolic anterior

motion of the mitral valve • Hemodynamic goals are to limit contractility,

avoid increases in heart rate and decreases in afterload, maintain preload

• Short acting β-blockers are important

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Pathophysiology: Obstructive Lesions



(ed.) 2012, p. 77

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

Right Sided Obstructive Lesions Transposition of the Great Arteries

Single Ventricle Lesions Miscellaneous

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Pulmonary Stenosis


Pulmonic Stenosis

• Valvar, subvalvar, supravalvar levels • Valvar PS can be mild, moderate, severe, or

critical • PGE1 may be needed to maintain PDA in

neonate with severe/critical PS • Percutaneous valvuloplasty is employed for

most neonates

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Systemic to Pulmonary Artery Shunt • For neonates and infants with pulmonary atresia

or severe pulmonic stenosis with cyanosis – Also termed Blalock-Taussig (BT) shunt – 3.0-4.0 mm PTFE graft

• PGE1 often required for PDA until surgery – May also stent PDA in cath lab

• Sternotomy with or without bypass, or right thoracotomy without bypass

• Beware large shunt in small infant especially with single ventricle

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Systemic to Pulmonary Artery Shunt



(ed.) 2012, p. 112

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Tetralogy of Fallot: Anatomy

R aortic arch (25%)


L., (ed.) 2012, p. 111 25


Tetralogy of Fallot • Cyanosis ranges from none (“Pink Tet”) with

minimal RVOTO to severe with pulmonary atresia

• “Tet Spell” is hypercyanosis from increased RVOTO, tachycardia, hypovolemia, causing increased right-to-left shunting – Catecholamine surge from pain or light anesthesia

• Treatment is increasing FiO2 to 1.0, deepening anesthetic (fentanyl), volume infusions, IV phenylephrine, B-blockade

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Tetralogy of Fallot Repair • Normally a complete repair is performed in the

first 6 months of life • If pulmonary atresia, or cyanotic as young infant

– Complete repair or systemic to pulmonary artery shunt

• Transatrial, transpulmonary approach with CPB • VSD patch, resect RVOT muscle, relieve PS

– Transannular incision often necessary, RVOT patch – Often varying degrees PI – RV-PA conduit if pulmonary atresia – Beware R coronary across RVOT

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Tetralogy of Fallot Repair

pediatricheartspecialists.com 28


Rastelli Repair

• Utilized for Tetralogy of Fallot with pulmonary atresia, Truncus arteriosus, D-TGA with pulmonic stenosis

• VSD repair, and RV to PA valved conduit • Takedown of PAs from truncus • Tunnel-patch for D-TGA and PS

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Rastelli Repair

www.med.umich.edu 30


Pulmonary Atresia/Intact Septum


Anesthesia and Uncommon Diseases, 6th Ed., Fleisher

L., (ed.) 2012, p. 113 31


Pulmonary Atresia/Intact Septum

• Pathophysiology and treatment depend on RV size

• Small RV often leads to coronary sinusoids and RV dependent coronary circulation – Coronary ischemia is common in these patients

• Patients with larger RV can undergo two ventricle or one-and-a-half ventricle repairs

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Pathophysiology: Obstructive Lesions



(ed.) 2012, p. 77

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Management of Pacemakers/Defibrillators • Consult EP service/pacemaker manufacturer • Clearly understand indications for pacemaker/defibrillator • Understand underlying rhythm

– AV node ablation or very slow/no ventricular escape • Interrogate function of device • Convert to asynchronous mode (DDD), suspend

antitachycardia functions • Backup pacemaker/defibrillator capability • No electrocautery through generator/leads • Monitor perfusion at all times: pulse ox, art line • Interrogate device/restore baseline settings after case

Anesthesiology 2011;114:247

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Pacing, Cardioversion, Defibrillation for CHD patients with hemodynamically significant

arrhythmias Treatment Dose Indications Comments

Atrial overdrive pacing with temporary wires/permanent PM

10-20% faster than SVT rate for up to 15 sec

SVT

Atrial pacing with temporary wires

Desired rate for optimal hemodynamics

Sinus /junctional bradycardia JET

Output double the capture threshold

AV sequential pacing with temporary wires

Desired rate for optimal hemodynamics

AV block Output double the capture threshold

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Anesthesia and Uncommon Diseases, 6th Ed., Fleisher L., (ed.) 2012, p. 82


Pacing/Cardioversion/Defibrillation (continued) Treatment Dose Indications Comments

Synchronized cardioversion

0.5-1 joule/kg SVT, Atrial Flutter, A fibrillation

Sedation, analgesia needed

Defibrillation 3-5 joules/kg VT, VF

External transcutaneous pacing

Increase output till capture; desired rate for optimal hemodynamics

Sinus/junctional bradycardia, AV block

Temporary therapy in emergencies

Esophageal pacing Overdrive for SVT; desired rate for optimal hemodynamics

Sinus bradycardia, SVT

Not effective for AV block

Trans-venous pacing Increase output till capture; desired rate for optimal hemodynamics

AV block; sinus/junctional bradycardia

Temporary therapy; ineffective for SV patients

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Reference Sources

1. Andropoulos DB, Gottlieb EA: Chapter 3: Congenital Heart Disease. In Fleisher L. (ed.), Anesthesia and Uncommon Diseases, 6th Ed., Philadelphia, Elsevier, 2012.

2. Andropoulos DB, Stayer SA, Russell IA, Mossad EB (eds.) Anesthesia for Congenital Heart Disease, 2nd Edition. Oxford UK, Wiley-Blackwell, 2010.

3. Odegard KC, DiNardo JA, Laussen PC. Chapter 25: Anesthesia for Congenital Heart Disease. In Gregory GA, Andropoulos DB (eds.) Pediatric Anesthesia, 5th Edition. Oxford UK, Wiley-Blackwell, 2012.

4. de Souza, McDaniel, Baum, DiNardo, Shukla, McGowan, Kussman: Chapters 4, 20, 21 . In Davis /Cladis/ Motoyama (eds.) Smiths Anesthesia for infants and Children, 8th edition . Philadelphia, Mosby- Elsevier 2011.

5. Slesnick, Gertler, Miller-Hance, McEwan, Shukla, Steven, McGowan, Andropoulos, Diaz, Chang, Davidson, Skinner, Lane : chapters 14-16, 19-21 In Cote, Lerman, Todres (eds.) A Practice of Anesthesia For infants and Children, 4th Edition. Philadelphia, Saunders- Elsevier, 2011.

6. Society for Pediatric Anesthesia, Critical Events Checklists; www. pedsanesthesia.org

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Pediatric Cardiac Anesthesia 3: Obstructive Lesions

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