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

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

2. Background • Congenital Heart Disease 8/1000 live births • “Critical” CHD 3/1000 live births • Death • - Cardiac catheterization • - Surgery

3. 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

7. 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%)

8. Clinical Presentation of CHD in the Neonate • Fetal Diagnosis • Cyanosis • CHF/Shock/Circulatory Collapse • Arrhythmia • Asymptomatic Heart Murmur

9. 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

10. 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

11. 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

12. 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

13. 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.

14. 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

15. CHD in the Neonate - CyanosisPO2<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

16. Cyanotic Congenital Heart Disease “Right Sided” Early Presentation

17. VSD-PS; if severe- may require open PDA for PBF

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

19. Pulmonary Atresia-Intact Ventricular Septum • Suprasystemic RV • pressure • TR • CoronarySinusoids

20. RV-Coronary Connections in PA-IVS

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

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

23. Tetralogy of Fallot- Anterior MalalignmentVSD

24. Severe Sub PS in TOF with Hypoplastic PAs

25. Truncus Arteriosus • Conotruncal Defect • VSD • Abnormal Truncal Valve • Single Great Artery • Gives Rise to: • coronary arteries • pulmonary arteries • brachiocephalic arteries • 35% 22q11 Microdeletion

26. Profound hypoxemia • Low pO2 • High pCO2 • -Shock in the first 48 hours • CXR-small heart, white lungs

27. Supracardiac TAPVR Lateral Angiogram

28. 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

29. Balloon Atrial Septostomy-Cath

31. Clinical Presentation of CHD in the Neonate • Cyanosis • Congestive Heart Failure • Asymptomatic Heart Murmur • Arrhythmia

32. 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)

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

34. CHF/Shock in the Neonate • Evaluation for and treatment of • presumptive sepsis should be • undertaken simultaneously.

35. Upon Closure of PDA: - acute  LV afterload -  gut, renal perfusion - CHF and acidosis

36. Posterior Malalignment VSD: • Sub-Aortic Stenosis • - 75% 22q11 Microdeletion

37. Interrupted Aortic Arch AP View Lateral View Restrictive PDA

38. LV dysfunction in utero • Endocardial • Fibroelastosis (EFE) • PDA necessary for • systemic perfusion • PFO necessary for • PV return to reach • systemic circulation

39. 1/5000 Live Births Lower Body, CNS and Coronaries Dependant Upon Patent Ductus

40. Profound CHF-Shock Upon • Ductal Closure • NEC • Hypoxic-Ischemic • CNS Damage • Myocardial Failure

41. 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

42. SVC atrial RA LA IVC septum pv SINGLEVENT LV PA LUNGS (PVR) BODY (SVR) PDA-Ao Qs Qp Physiology of HLHS

43. 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

44. 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

45. 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)

47. 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 deliverydecreases

48. 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%

49. 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

50. 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