Critical Congenital Heart Disease in the Newborn: Anatomy, Physiology and Surgical Management

Critical Congenital Heart Disease in the Newborn:

Anatomy, Physiology and Surgical Management

Bradley S. Marino, MD, MPP, MSCE

Associate Professor of PediatricsStaff Cardiac Intensivist, Cardiac Intensive Care Unit

The Divisions of Cardiology and Critical Care MedicineCincinnati Children’s Hospital Medical Center University of Cincinnati College of Medicine

Background

• Congenital Heart Disease 8/1000 live births

• “Critical” CHD 3/1000 live births- Death- Cardiac catheterization- Surgery

Scope of the Problem

• In the USA:

- ~ 32,000 children born/year with CHD

- ~ 11,000/year with “Critical” CHD

- ~ 150,000 children in US school system with “repaired” CHD

0

250

500

750

1000

Incidence of Common Childhood Diseases/100,000 Popluation

0

10

20

30

40

Incidence/100,000

CHD Presenting in the Neonatal Period

0-6 days 7-13 days 14-28 days(n=1603) (n=311) (n=306)TGA (15%) Coarct (20%) VSD (18%)HLHS (12%) VSD (14%) TOF (17%)TOF (8%) HLHS (9%) Coarct (12%)Coarct (7%) TGA (8%) TGA (10%)VSD (6%) TOF (7%) PDA (5%)Other (52%) Other (42%) Other (38%)

Clinical Presentation of CHD in the Neonate

• Fetal Diagnosis

• Cyanosis

• CHF/Shock/Circulatory Collapse

• Arrhythmia

• Asymptomatic Heart Murmur

Clinical Presentation of CHD in the Neonate

Timing and Symptoms depend on

(1) anatomic defect(2) in utero effects (if any)(3) physiologic changes – transitional circulation

closure of the ductus arteriosus and fall in pulmonary vascular resistance

Newborn Presentation of CHD• Cyanosis

- Usually minimal symptoms- First 48-72 hours of life- Duct-dependent pulmonary blood flow

- Mixing lesion:TGA, TAPVC, Truncus Arteriosus

• CHF/Circulatory Collapse/Shock- First 2 weeks of life- Duct-dependent systemic blood flow- Secondary end-organ dysfunction

Heart, Brain, Kidneys, GI

Evaluation of the Cyanotic Neonate• Cyanosis occurs if there is >3.0g/dL of

deoxygenated hemoglobin:– ambient lighting– skin color – hemoglobin; for O2 saturation of 80%

• if Hg is 20 gm/dl; 4 gm desaturated-visible cyanosis

• if Hg is 10 gm/dl; 2 gm desaturated-not cyanotic

• Hyperoxia Test to Determine Intrapulmonary vs. Intracardiac Shunt

Neonatal Presentation-Cyanosis Hyperoxia Test

• Room air (if tolerated)• pO2 directly measured or TCOM• 100% FIO2 - “blow-by”, mask, intubated• Repeat mesurement of pO2 right radial artery

Must note site of measurement Pulse oximetry not acceptable

Hyperoxia Test - Interpretation

• pO2 < 100; cyanotic CHD likely

• pO2 100-250; cyanotic CHD possible

• pO2 > 250; cyanotic CHD unlikely

A “failed” hyperoxia test is a neonatal emergency - urgent intervention.

CHD in the Neonate - Cyanosis

• For PO2<50 there is a limited number of diagnoses possible• Chest Xray VERY Helpful

- Massive Cardiomegaly = Ebstein’s Anomaly- Pulmonary Edema = TAPVC- Increased PBF = d-TGA with IVS- Decreased PBF right sided obstructive lesion with intracardiac R to L shunting

CHD in the Neonate - CyanosisPO2<50 with Decreased PBF

• ECG and Cardiac Exam

Pulmonary Stenosis vs Pulmonary Atresia with IVS

Tricuspid Atresia with PS vs Tricuspid Atresia/Pulmonary Atresia

Tetralogy of Fallot vs Tetralogy of Fallot/Pulmonary Atresia

Cyanotic CongenitalHeart Disease

“Right Sided”Early Presentation

VSD-PS; if severe-

may require

open PDA for PBF

Ebstein’s Anomaly •In-utero TR hydrops• SVT common• Sub PS from TV tissue• iNO helpful to lower PVR and encourage antegrade PBF

Pulmonary Atresia-Intact Ventricular Septum

- Suprasystemic RV pressure-TR- CoronarySinusoids

RV-Coronary Connectionsin PA-IVS

“Critical” Pulmonary Stenosis

-“Duct-Dependant” PBF

-Non-compliant RV

-RL atrial shunt through ASD or PFO

- Anterior Malalignment VSD- Aortic Override- Sub PS- RVH-25% 22q11Microdeletion

Tetralogy of Fallot-Anterior MalalignmentAnterior Malalignment VSD

Severe Sub PS in TOF with Hypoplastic PAs

Truncus ArteriosusTruncus Arteriosus

Conotruncal Defect• VSD• Abnormal Truncal Valve• Single Great Artery Gives Rise to:

• coronary arteries• pulmonary arteries• brachiocephalic arteries

• 35% 22q11 Microdeletion

Profound hypoxemia-Low pO2-High pCO2-Shock in the first 48 hours

CXR-small heart, white lungs

Supracardiac TAPVR Lateral Angiogram

Survival Dependant Upon Mixing Between Systemic and Pulmonary Circuits (PFO, VSD, PDA)

- 40% with VSD- PDA PGE1

-Balloon Atrial Septostomy in most cases of TGA/IVS

Balloon Atrial Septostomy-Cath

Clinical Presentation of CHD in the Neonate

• Cyanosis

• Congestive Heart Failure

• Asymptomatic Heart Murmur

• Arrhythmia

Congestive Heart Failure

• Clinical Syndrome marked by inability of the heart to meet the metabolic demands of the body

• After the first 24-48 hours of life, the neonate with CHF/shock has duct-dependent, left-sided heart disease until proven otherwise

• Coarctation of the Aorta• Interrupted Aortic Arch• Critical Aortic Stenosis• Hypoplastic Left Heart Syndrome (HLHS)

CHF may be the result of:• Increased demand

- volume or pressure overload• Normal demand but decreased function

- Inflammatory or metabolic disease

Congestive Heart Failure

CHF/Shock in the Neonate

• Evaluation for and treatment of presumptive sepsis should be undertaken simultaneously.

Upon Closure of PDA:

- acute LV afterload- gut, renal perfusion- CHF and acidosis

Posterior Malalignment VSD:

- Sub-Aortic Stenosis- 75% 22q11 Microdeletion

Lateral ViewRestrictive PDA

Interrupted Aortic ArchAP View

LV dysfunction in utero

- Endocardial Fibroelastosis (EFE)- PDA necessary for systemic perfusion- PFO necessary for PV return to reach systemic circulation

1/5000 Live Births

Lower Body, CNS and Coronaries Dependant Upon Patent Ductus

Profound CHF-Shock UponDuctal Closure

• NECNEC• Hypoxic-IschemicHypoxic-Ischemic CNS DamageCNS Damage• Myocardial FailureMyocardial Failure

CHF/Shock--Metabolic Acidosis

Usually due to decreased tissue perfusionrather than hypoxemia

Multifactorial - closing PDA, myocardial dysfunction, shunting of systemic circulation into lungs

Treatment:NaHCO3/Inotropic Support/Sedation/ParalysisPGE1

RARA

SINGLESINGLEVENTVENT

SVCSVC

IVCIVC

PDA-AoPDA-AoBODY(SVR)

QsQs

atrial

septum

QpQp

LUNGS(PVR)

PAPA

LALA

LVLV

pvpv

Physiology of HLHS

Critical CHD Is Suspected• Hyperoxia Test indicates Cyanotic CHD (Ductal Dependent PBF) or Shock >48 hours of age (Ductal Dependent SBF) – Heart Disease Likely

- PGE1 0.05-0.1 mcg/kg/min

- Observe 20-30 minutes

- Repeat ABG and Vital Signs

- Umbilical lines

Side Effects of PGE-1 By Birth Weight<2 >2KG KG

______________________________________CV 37% 17%CNS 16 16Respiratory 42 10Metabolic 5 2Infectious 11 2GI 11 3Hematologic 5 2Renal 0 2

Prostaglandin E1• Apnea

• Vasodilation/Hypotension

• Fever

• Seizures (rare)

• May “unmask” CHD with obstruction to PV return– TGA with intact atrial septum– TAPVR– Mitral atresia with small PFO (DORV/MA, HLHS)

Critical Neonatal CHD- CHOP 1997-1999

21%

45%

18%

7%

4%

5%

Duct-Dependant PBFDuct-Dependant SBFTGATAPVRTruncusOther

Supplemental O2 in Critical CHD

• Oxygen is a potent pulmonary vasodilator• In lesions with duct-dependant systemic or pulmonary blood flow (~80% of critical CHD)• Lowering PVR “steals” systemic cardiac output through PDA• PBF increases at the expense of SBF• As systemic oxygen saturation increasesincreases, systemic oxygen delivery decreasesdecreases

Supplemental O2 in Critical CHD

• If systemic cardiac output is normal• If hemoglobin and O2 consumption are normal• An oxygen saturation of ~75-85% provides adequate oxygen delivery to prevent metabolic acidosis• Titrate supplemental O2 to saturation ~ 80%

Perioperative Management

• Initial Stabilization– Airway management– Vascular Access– Newborns-maintenance of PDA

• Echocardiographic Diagnosis• Evaluation and Treatment of Secondary Organ

Dysfunction• Cardiac Catheterization, if necessary• Surgical Management

The Neonate with Critical CHDEchocardiography

• Anatomic and Physiologic Assessment• Serial Changes• Not “Non-Invasive”

- Temperature Instability- Subcostal View- Suprasternal Notch View - ? Airway Compromise- Time Consuming

Echo is not“non-invasive” inthe sick neonate

Evaluation of Other Organ Systems

• Genetics– dysmorphism– multiple congenital anomalies (25% of

CHD)– conotruncal malformations– A-V canal malformations (T21)– diffuse arteriopathies (Williams)

Evaluation of Other Organ Systems

• Central Nervous System– Hypoxia-ischemia at Presentation– Multiple Congenital Anomalies– Seizures– Prematurity

Evaluation of Other Organ Systems

• Renal (3-6% CHD)– Two Vessel Cord– VACTERL association

• Gastrointestinal (1-3% CHD)– Necrotizing enterocolitis– Malrotation (heterotaxy)– Functional Asplenia (heterotaxy)– Duodenal Atresia (Trisomy 21)– Esophageal Atresia (VACTERL)

Conclusion

• Critical CHD 1/300 live births• Cyanosis Right-sided lesions or Mixing Lesions• CHF/Shock Left-sided lesions• The term neonate who presents with

CHF/shock after the first 24-48 hours of life

has duct-dependant CHD until proven otherwise

• PGE1 necessary in ~80% of critical CHD

• Titrate supplemental O2 to saturation ~ 80%