CASE PRESENTATION

1
CASE PRESENTATION

• This is a two-day old male infant, born weighting
  2730 grams (six pounds, two ounces) after a
  full-term pregnancy complicated by influenza in
  the first trimester, was found to be tachypneic
  on the second day of life. Examination at that
  time also revealed weak peripheral pulses. He was
  transferred to the university hospital.

2
CASE PRESENTATION (cont.)

• On admission, physical examination revealed a
  small tachypneic infant with grayish cyanosis of
  the lips. The respiratory rate was 89 per minute
  and the heart rate 170 per minute. The lungs were
  clear to auscultation. A right ventricular lift
  was noted at the left sternal border and in the
  epigastric area. No thrills were present.

3
CASE PRESENTATION (cont.)

• The first heart sound was normal but the second
  sound was closely split with a loud, snappy
  pulmonic component. A short, soft ejection
  systolic murmur was present at the fourth left
  intercostal space. The peripheral pulses could
  not be palpated in either the upper or lower
  extremities. The liver edge was palpable 3-4 cm
  below the RCM.

4
QUESTIONS

• The differential diagnosis of congestive heart
  failure in the first few days of life include all
  the following except
• A. TAPVR
• B. Myocarditis
• C. Hypoplastic left heart syndrome
• D. Preductal coarctation of the aorta
• E. VSD

5
QUESTIONS (cont.)

• Anatomical components of the hypoplastic heart
  syndrome include all the following except
• A. Aortic atresia
• B. Minute left ventricle
• C. Mitral atresia, stenosis or hypoplasia
• D. PDA
• E. Pulmonary atresia

6
QUESTIONS (cont.)

• 3. Which of the following findings is not a
  typical one in patients with HLHS?
• A. Fairly sudden onset of tachypnea and dyspnea
  during the first week of life.
• B. Loud aortic component of the S2.
• C. Loud pulmonary component of the S2.
• D. Weak peripheral pulses.
• E. Cyanosis

7
HYPOPLASTIC LEFT HEART SYNDROME

• Gerardo Gonzalez, MD

8
HLHS - History

• First described in 1952 by Lev as the pathologic
  complex hypoplasia of the aortic tract,
  including cases of
• isolated hypoplasia of the aorta
• hypoplasia of the aorta and VSD
• hypoplasia of the aorta with aortic stenosis or
  atresia, with or without mitral stenosis or
  atresia
• In 1958, Noonan and Nadas termed these lesions as
  hypoplastic left heart syndrome.

9
HLHS - Embryology

• The embryologic cause is not fully understood.
• It probably results from a limitation of either
  LV inflow or outflow, such as the development of
  severe AS early.

10
HLHS - Genetics

• Familial inheritance
• Autosomal recessive and multifactorial
  inheritance have both been postulated.
• Sibling recurrence risk 0.5
• Sibling recurrence for all other cardiac
  malformations 2.2
• Definable genetic disorder (28)
• Turner Syndrome
• Noonan Syndrome
• Trisomy 13, 18, 21, or other microdeletion
  syndromes

11
HLHS - Epidemiology

• Each year, approximately 1000 infants with HLHS
  are born in the US.
• Prevalence 0.016-0.27 per 1000 live births.
• In pathologic series, it accounts for 1.4-3.8 of
  congenital heart disease.
• Third cause of critical CHD in the newborn.
• Male predominance 57-70.
• 23 of all neonatal mortality from CHD.

12
HLHS Epidemiology (cont.)

• Infants with HLHS are usually full term they
  have a normal birth weight and few significant
  extracardiac malformations.
• Prematurity and SGA at birth are observed in
  5.5.
• Noncardiac malformations are uncommon (12).
• Serious or major malformations are rare (2.3)

13
Anatomy
14
HLHS - Pathophysiology

• The term HLHS is used to describe a related
  group of anomalies that include underdevelopment
  of the left side of the heart (e.g. atresia of
  the aortic or mitral orifice) and hypoplasia of
  the ascending aorta.
• The left ventricle may be small and nonfunctional
  or totally atretic.

15
HLHS - Pathophysiology

• The right ventricle maintains both pulmonary and
  systemic circulations.
• Pulmonary venous blood passed through an atrial
  defect or dilated foramen ovale from the left to
  the right side of the heart, where it mixes with
  systemic venous blood (TOTAL MIXING LESION).
• The ventricular septum is usually intact.

16
HLHS - Pathophysiology

• The major hemodynamic abnormalities are
• Inadequate maintenance of the systemic
  circulation.
• Pulmonary venous hypertension (if restrictive
  foramen ovale).
• Pulmonary overcirculation (if moderate or large
  ASD).

17
Anatomy
18
HLHS Clinical manifestations

• Most infants are diagnosed in the first few hours
  or days of life.
• A grayish blue color of the skin is soon apparent
  (denoting a mix of cyanosis and hypoperfusion).
• If the PDA partially closes, signs of systemic
  hyporperfusion and shock predominate.

19
HLHS Clinical manifestations

• Signs of HF usually appear within the first few
  days or weeks of life (dyspnea, hepatomegaly, low
  cardiac output).
• Peripheral pulses may be weak or absent.
• Cardiac enlargement is usual, with a right
  ventricular parasternal lift.
• A nondescript systolic murmur is usually present.

20
HLHS Clinical manifestations

• Extracardiac anomalies (particularly of the
  kidney and CNS, but also diaphragmatic hernia,
  omphalocele and hypospadia) may be present.

21
HLHS Diagnostic tools

• CXR
• Heart variable in size (1st day of life).
• Cardiomegaly develops rapidly, associated with
  increased pulmonary vascularity.

22
Chest X-ray of a two-day- old boy with HLHS
23
HLHS Diagnostic tools

• Electrocardiogram
• Initially, may show only the normal right
  ventricular predominance.
• Later, P waves become prominent and right
  ventricular hypertrophy is usual.

24
ECG
25
ECG
26
HLHS Diagnostic tools

• Echocardiogram
• Is diagnostic.
• There is absence or hypoplasia of the mitral
  valve and aortic root, a variable small left
  atrium and left ventricle, and a large right
  atrium and right ventricle.
• The size of the atrial communication can be
  assessed directly and by pulsed and color flow
  Doppler studies.

27
HLHS Diagnostic tools

• Echocardiogram (cont.)
• Suprasternal notch views identify the small
  ascending aorta and transverse aortic arch (may
  also demonstrate a discrete CoAo).
• Doppler demonstrates the absence of anterograde
  flow in the ascending aorta and retrograde flow
  via the ductus arteriosum.

28
NORMAL 4-CHAMBER VIEW
LA
RA
LA
RV
LV
29
4-CHAMBER VIEW - HLHS
30
4-CHAMBER VIEW AORTIC ATRESIA WITH MITRAL
ATRESIA
31
NORMAL SHORT-AXIS VIEW
RV
AO
PA
RA
LA
32
SHORT-AXIS VIEW - HLHS
33
NORMAL LONG-AXIS VIEW
RV
LV
AO
LA
34
LONG-AXIS VIEW - HLHS
35
HLHS Diagnostic tools

• Cardiac Catheterization and Angiography
• These are no longer routinely necessary for the
  diagnosis of HLHS.
• In patient with severe restriction at the
  interatrial level, a ballon septostomy would be
  indicated if the patient is not a candidate for
  surgical palliation at that time.

36
HLHS - Treatment

• There is variable success in the surgical therapy
  of HLHS.
• Management options include
• Norwood procedure
• Heart transplantation
• Supportive expectant care

37
HLHS - Treatment

• Norwood procedure Preoperative
  management
• correction of acidosis and hypoglycemia
• maintenance of the patency of the PDA (with PGE1)
  to support systemic blood flow
• prevention of hypothermia
• 21 FiO2, with addition of 2 to 4 CO2 (PCO2
  aimed at 50, pH 7.30)
• Selective use of small amount of inotropic agents
  (sepsis or RV failure)

38
BEFORE NORWOOD PROCEDURE
39
HLHS - Treatment

• Norwood Procedure First Stage
• Atrial septectomy.
• Transection and ligation of the main pulmonary
  artery.
• Connection of the proximal pulmonary artery to
  the transversely opened hypoplastic aortic arch
  (neoaorta). The coarcted segment of the aorta
  is repaired.

40
HLHS - Treatment

• Norwood Procedure First Stage (cont.)
• Modified Blalock-Taussig shunt.
• 90 early survival (if in a timely fashion at
  selected institutions).

41
Norwood Stage I
42
AFTER NORWOOD STAGE I
43
HLHS - Treatment

• Norwood Procedure Second Stage
• All prior shunts are removed.
• Glenn anastomosis (bidireccional cavopulmonary
  procedure) the superior vena cava is connected
  to the pulmonary arteries.
• 5 mortality.
• Usually performed around 6 months of age.

44
AFTER NORWOOD STAGE II
45
HLHS - Treatment

• Norwood procedure Third Stage
• Modified Fontan Procedure (cavopulmonary
  isolation) the inferior vena cava is connected
  to the pulmonary arteries, via either an
  intra-atrial of external baffle.
• 10-12 mortality.
• Usually performed around the age of 2 years.

46
After Stage III of Norwood Procedure
47
HLHS - Treatment

• After the third stage, all systemic venous return
  enters the pulmonary circulation directly.
• Pulmonary venous flow enters the left atrium and
  is directed across the atrial septum to the
  tricuspid valve, and subsequently to the right
  (now the systemic) ventricle.

48
HLHS - Treatment

• Blood leaves the right ventricle via the
  neoaorta, which supplies the systemic
  circulation.
• Coronary blood flow is provided by the old aortic
  root, now attached to the neoaorta.

49
HLHS - Treatment

• Cardiac Transplantation
• It is an alternative, either
• In the immediate neonatal period (obviating stage
  I of the Norwood procedure)
• After a successful stage I Norwood procedure
• Patients have the chronic risk of an organ
  rejection and lifelong immunosuppressive therapy.

50
HLHS Treatment

• Five year survival
• 70 for staged palliation (Norwood procedure).
• 75 for transplantation.

51
HLHS - Treatment

• Supportive expectant care (do nothing)
• Especially true when multiple noncardiac
  congenital anomalies exist or when serious
  multiorgan system damage is present.

52
HLHS Pitfalls for the Nursery

• Avoid using oxygen despite low pulse oximetry
  saturation.
• Increasing FiO2 will lower pulmonary vascular
  resistance and increase blood flow to the lungs,
  which are already overcirculated, thereby
  worsening systemic perfusion.

53
HLHS Pitfalls for the Nursery

• Avoid overventilating the infant.
• Carbon dioxide is a pulmonary vasoconstrictor
  and may improve systemic perfusion and cardiac
  output. Try to maintain normal or mildly elevated
  PaCO2 levels.

54
HLHS - Summary

• It is a collective term describing a group of
  cardiac malformations that share various degrees
  of hypoplasia of the structures of the left side
  of the heart.
• Over 95 of patients with HLHS will die if left
  untreated during the first month of life.
• Echocardiogram is the diagnostic procedure.
• Surgical intervention has become a medical
  standard.