Bradley S. Marino, MD, MPP, MSCE Critical Congenital Heart Disease in the Newborn: Anatomy, Physiology and Surgical Management Bradley S. Marino, MD, MPP, MSCE Associate Professor of Pediatrics Staff Cardiac Intensivist, Cardiac Intensive Care Unit The Divisions of Cardiology and Critical Care Medicine Cincinnati 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

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 - Cyanosis PO2<50 with Decreased PBF ECG and Cardiac Exam Tricuspid Atresia with PS vs Tricuspid Atresia/Pulmonary Atresia Tetralogy of Fallot vs Tetralogy of Fallot/Pulmonary Atresia Pulmonary Stenosis vs Pulmonary Atresia with IVS

Cyanotic Congenital Heart 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 Connections in PA-IVS

“Critical” Pulmonary Stenosis -“Duct-Dependant” PBF -Non-compliant RV -RL atrial shunt through ASD or PFO

- Anterior Malalignment VSD - Aortic Override - Sub PS - RVH 25% 22q11 Microdeletion

Anterior Malalignment VSD Tetralogy of Fallot- Anterior Malalignment VSD

Severe Sub PS in TOF with Hypoplastic PAs

Truncus 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)

Congestive Heart Failure CHF may be the result of: Increased demand - volume or pressure overload Normal demand but decreased function - Inflammatory or metabolic disease

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

Interrupted Aortic Arch AP View Lateral View Restrictive PDA

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 Upon Ductal Closure NEC Hypoxic-Ischemic CNS Damage Myocardial Failure

CHF/Shock--Metabolic Acidosis Usually due to decreased tissue perfusion rather than hypoxemia Multifactorial - closing PDA, myocardial dysfunction, shunting of systemic circulation into lungs Treatment: NaHCO3/Inotropic Support/Sedation/Paralysis PGE1

Physiology of HLHS Qs Qp SVC IVC atrial septum RA SINGLE VENT LA LV pv Let me take you through the physiology of HLHS. Systemic venous return enters the RA. In the absence of a patent mitral valve, or if the LV or aorta cannot allow for normal egress of blood, pulmonary venous return will obligatorily exit the LA via the atrial septal communication. Systemic venous blood and pulmonary venous blood then mix in the RA. Further mixing occurs as the 2 flows enter the single vent (RV). With contraction of the RV, blood enters the MPA and may take one of 2 routes: it may descend the ductus arteriosus and perfuse the body, or it may go to the lungs via the branch pulmonary arteries. Obviously both systemic flow to the body and pulmonary flow to the lungs are necessary for survival, however any one blood cell that goes to the lung is one that does not perfuse the body and vice-versa. Hence the key management of this physiology is creating an appropriate balance and distribution of blood flow bbetween the 2 parallel circuits . What are the Factors influencing the distribution of blood flow? One may think of this set-up in terms of a pump and 2 resistors. There are variable resistors and fixed resistor in this set-up. Variable resistors: 1) Ductus Arterious, constriction, 2) SVR (sepsis lowers svr, unnecessary pressors increase SVR, as does oxygen) 3) PVR : with PVR continues to drop and is progressively lowewr than SVR, hence pulm overcirculation is the rule (lung function, atelectasis, pneumonia, RDS, prematurity, oxygen) Fixed Resistors: anatomic 4) pulmonary venous connection and atrial septal morphology Discuss arterial blood gases and mixed venous saturations, Barnea paper SVC IVC atrial septum RA SINGLE VENT LA LV pv Qp LUNGS (PVR) PA PDA-Ao BODY (SVR) Qs

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 >2 KG KG ______________________________________ CV 37% 17% CNS 16 16 Respiratory 42 10 Metabolic 5 2 Infectious 11 2 GI 11 3 Hematologic 5 2 Renal 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)

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 increases, systemic oxygen delivery decreases

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 CHD Echocardiography 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” in the 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%