Critical Congenital Heart Disease in the Newborn: Anatomy, Physiology and Surgical Management
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Transcript of 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
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250
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Incidence of Common Childhood Diseases/100,000 Popluation
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10
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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%