Hypoplastic Left Heart
Syndrome (and the single
ventricle repair)
Henaro Sabino, MD
Sibley Heart Center Cardiology at Children’s
Healthcare of Atlanta; Emory University
CHEST PAIN, SYNCOPE
• “I’M COMIN’ HOME!”
GOALS
• Appreciation of history of Hypoplastic Left Heart
Syndrome.
• Basic anatomy & physiology.
• (DE-mystify Hypoplastic Left Heart Syndrome.)
• Understand the LOGIC behind the management of
HLHS (& single ventricle lesions in general).
• KEEP YOU ALL AWAKE FOR THE NEXT 1.25
HOURS.
Hypoplastic Left Heart Syndrome
• Spectrum of underdevelopment of the left ventricular
cavity.
 Have underdeveloped aortic & mitral valves (stenosis or
atresia).
 Left ventricle is unable to support systemic circulation
(and, therefore, right ventricle is used as the single
ventricle).
History of HLHS
• First described by Maurice Lev in 1952.
• Term used by Noonan & Nadas in 1958.
• Options offered:
 Comfort care
 Staged palliative repair, i.e. “Norwood procedure”
First successful 3-stage completion in 1983 (after multiple
surgeries from 1979).
 Cardiac transplant
First successful cardiac transplant: Bailey, Nov. 1985
1980s
Xenotransplantation, “Baby Fae”
• Dr. Leonard Bailey, Loma Linda University Medical
Center, November 1984.
• http://www.babyfae.com
Anatomy
HLHS Epidemiology
• Low incidence of 1.6 to 3.6 per 10,000 live births, BUT causes
23% or cardiac deaths during 1st week of life and 15% during
the 1st month of life.
• Makes up about 2-4% of congenital heart disease.
• More commonly males (55% to 67%).
• With ONE affected child, recurrence risk is about 0.5% to 2%.
• 12% prevalence of left-sided obstructive lesions in 1st degree
relatives.
• 15-30% incidence of genetic syndromes and extracardiac
anomalies in patients w/HLHS.
• Genetic markers: dHAND, HRT1, HRT2, NOTCH.
•
Moss & Adams, 2008.
PATHOPHYSIOLOGY
• Cardiac development: “Flow begets growth.”
• Altered flow through the left side of the heart:
 Reduced/altered flow across the foramen ovale.
 Aortic or mitral obstruction.
Typical Clinical Presentation
• Known Congenital Heart Defect
 Prenatal Diagnosis
• Unknown Congenital Heart Defect
 Normal pregnancy, labor and delivery
 Clinically doing okay until the PDA closes **
 Cyanosis that does not improve with
oxygen
 Many have no other obvious anomalies
DUCTAL-DEPENDENT LESION
• PDA needed to:
 Provide systemic perfusion
HLHS **
Critical aortic stenosis
 Provide pulmonary blood flow
Tricuspid atresia
Pulmonary atresia
 Provide mixing of oxygenated & deoxygenated blood
Transposition of the Great Vessels
Hyperoxitest
• ABG is measured on room air.
• Patient is placed on 100% oxygen (intubated) for 10-15
minutes, then ABG is repeated.
 If problem is respiratory (i.e. hypoventilation), then
PaO2 improves (usually above 200mmHg).
 If problem is cardiac (i.e. right-to-left intracardiac
shunt), there is little improvement of PaO2.
 Primary pulmonary hypertension may also result in
little improvement of PaO2.
 (Oxygen may hasten closure of PDA!)
Positive Hyperoxitest
• Seriously consider initiation of prostaglandin (PGE) at
a low dose (0.03 mcg/kg/min) until diagnosis is
confirmed.
Initial Assessment
• ALWAYS
 A - Airway
 B - breathing
 C – circulation
CXR and ECG usually not very helpful in Dx.
Physical Findings
• Comfortable or in distress?
 Cyanosis w/out respiratory distress is cardiac until
proven otherwise
• Active or lethargic?
• Cyanosis?
 Degree - saturation usually <85% to be seen
 Anemia makes cyanosis difficult to notice
• Pallor
 Vasoconstriction from circulatory shock
• Perfusion and Peripheral pulses
• End organs (i.e. watch UOP)
Respiratory Status
• Tachypnea but with minimal distress…cardiac
until proven otherwise.
Respiratory Status
• Respiratory distress
 Inability of the respiratory system to
compensate for the metabolic acidosis
• Concurrent respiratory disease
• Unrelenting metabolic acidosis - decreased
cardiac function
• Exhaustion
Assisted Ventilation
• Intubate if:
 Impending respiratory failure
 Potentially not necessary to intubate just for
PGE therapy if ground transport
 Intubate for air transport in PGE dependent
babies
Assisted Ventilation
• Ventilation strategy
 Volume ventilation if possible to maintain
consistent minute ventilation in the face of
changing lung compliance
 Bigger tidal volumes compared to premature
newborns (10 cc/kg); lower rates
 No need to “over-ventilate”
 “40/40/40 club”
Arterial Blood Gases
• In congenital heart disease typically:
 Compensated or partially compensated
metabolic acidosis
 Arterial PO2 usually low <50 with cyanotic
heart disease…but not always
• If PCO2 is rising, think respiratory failure - be
ready to intubate!
Blood Gases
Arterial
Capillary Venous
PH
accurate
accurate
lower
PO2
accurate
invariable lower
PCO2
accurate
accurate
higher
HCO3 (calculated)
accurate
accurate
accurate
Oxygen
• Oxygen is a drug - use it with respect
• Oxygen is a pulmonary vasodilator
 May worsen pulmonary congestion
• Oxygen is a stimulus for the PDA to close
 May worsen ductal dependent lesions by
speeding up closure of the PDA
• Oxygen is not bad
Saturation Monitoring
• Oxygen saturation reflects tissue
oxygenation and usually does not correlate
with PO2.
• With pulmonary hypertension will see
differential cyanosis - shunts right to left
across the PDA.
• The number is not as important as the
patient.
Prostaglandin Infusion
• Purpose is to open the PDA if a ductal
dependent lesion is suspected
• Can be initiated before a definitive diagnosis
is established
• Need a secure IV (PIV, PIC, or UVC-central or
in the liver)
• Start at low dose 0.03 mcg/kg/min
Prostaglandins continued
• Side effects  Apnea - be prepared to intubate
 Fever
 Hypotension - have volume and inotropes
available
 Flushing
Access
• Umbilical is preferred in a newborn
 UVC – even if in suboptimal position
 UAC
• PIC line
• PIV
• AVOID groin line if possible
Fluid Resuscitation
• Needed if poorly perfused
• 5% albumin bolus (5-10 cc/kg)
• Watch for and treat hypoglycemia - stress
causes epinephrine release which
increases utilization of glucose.
• PRBC to treat anemia - optimize oxygen
carrying capacity.
Hypotension
• Check ionized calcium
 Treat with 50-100mg/kg calcium gluconate or
10 mg/kg calcium chloride via central access
• Dopamine 3mcg/kg/min increase as
needed (no higher than 10 mcg/kg/min)
Metabolic Acidosis
• Treat metabolic acidosis aggressively
(base deficit < -3)
• 1 meq/kg Na bicarbonate
• Repeat blood gas
Other Systems
• Renal function
 Urine output
 BUN/Cr
 Renal ultrasound
• Head ultrasound
• Liver function tests
• Coagulopathy
• Thrombocytopenia
• R/O sepsis
• Genetics
Fetal Diagnosis
Fetal Studies
• Hornberger, 1995: 21 fetuses with prenatal echos that
show left-sided obstruction (small mitral valve &
ascending aorta) developed HLHS.
• Critical aortic stenosis  decreased blood flow through
left heart  LV dilation & dysfunction  endocardial
fibroelastosis (EFE)  backwards flow across PFO 
LV stops growing & eventually shrinks
HLHS
NORMAL FETAL 4-CHAMBER
Case Presentation
•
•
•
•
Term infant born via SVD
Uncomplicated labor and delivery
APGARs of 8 at 1min., 9 at 5min.
Tachypnea noted at 12hrs of life.
Case Presentation
• “Airway-Breathing-Circulation”
 Respiratory rate (60-90 bpm)
 Work of breathing (no retractions)
 Saturations (80%)
 Warm extremities; good cap refill
Case Presentation
No obvious dysmorphic features.
More Cardiac Exam Findings:
 No murmur.
 Single second heart sound (S2).
 Hyperdynamic precordium.
Case Presentation
• Urgent Cardiology Consult
404-256-2593!!
• Cardiac History & Physical
• Echocardiogram
Echocardiogram HLHS
Hypoplastic Left Heart Syndrome
Case Presentation
• BUT:
 No beds available at Egleston
immediately
 Need to manage infant for 24 hours
before transport
• NOW what do we do?
Case Presentation
• Intravenous access
 UVC (double lumen)
 UAC
 PIV
 PIC
Remember: AVOID groin lines
Case Presentation
• Prostaglandins
 0.03 mcg/kg/min
• Side effects
 Apnea
• Options ?
• Intubate vs nasal cannula air
Case Presentation
• Labs






Arterial (or venous) blood gas
Electrolytes (normalize)
CBC
LFT
Genetics
Lactic acid
• Head and Renal ultrasound
• ECHO/EKG
Case Presentation
• R/O Sepsis
 If no clinical suspicion or maternal
indicators no need to start antibiotics
•
•
•
•
Follow ABG frequently (Q 4 hrs)
Monitor urine output
Monitor for acidosis
Watch for hypotension
Blood Pressure
• Blood pressure - systolic and diastolic
blood pressures are equally important…not
just mean!!
 Coronary flow to heart dependant on
diastolic BP
Case Presentation
• Saturations 95%
• pO2 50
• Decreased urine output
• Metabolic acidosis
• Rising lactic acid
What’s going on?!?
Chest X-Ray
Case Presentation
• Pulmonary Over Circulation with systemic
compromise
 Intubate/hypoventilate
 CO2
Hypoplastic Left Heart Syndrome
Case Presentation
• “Y- tube” Physiology:
To Lungs
Pulmonary Resistance
Lowered by:
- Oxygen
- Prostaglandin
- Resp alkalosis
Raised by:
- PPV
- Hypoxia
- Resp acidosis
To Body
Systemic Resistance
Raised by:
- Dopamine
- Epinephrine
Monitoring Innovations
• Lactic Acid
• Mixed venous oxygen saturation
• Near infrared spectroscopy
Pulmonary Atresia
“Hypoplastic RIGHT Heart”
“Flow begets
growth”
Same “Y-tube” Physiology
To Lungs
But now not
enough blood flow
to lungs
To Body
“Ideal” Saturation for PDA-dependant
• For ‘balanced’ amount of blood flow to both the
lungs and the body in a single ventricle (i.e. “Ytube physiology” infant) is:
75% to 85% oxygen saturation
(in upper extremity)
Options for HLHS in 2010
•
•
•
•
Comfort Care
Transplant
3-Stage Palliative Repair
Fetal Intervention
Cardiac Transplant
• Fairly good quality of life as transplant recipient
(…have structurally normal heart).
• Obstacles:
 Availability of donor heart (approximately 25-30% die
awaiting transplant).
 Life-long immunosuppression & risk of infection/CA.
 Usual cause of death/organ death: coronary
vasculopathy.
 Survival: 84% at 1 yr, 76% at 5 yrs., 70% at 7 yrs.
 Organ survival MUCH reduced w/subsequent
transplants.
HLHS Palliative Repair
A. HLHS (sats 80s)
B. Norwood repair in 2wks
- Provide systemic BF
- Balance pulmonary BF
C.
Glenn repair (SVC to PA)
- More pulmonary BF
D. Fontan repair (IVC to PA)
- Relieve volume load to RV
- Venous blood totally
bypasses heart (sats
100%)
Norwood (Stage I)
HLHS Survival
• Standard Risk (i.e. no genetic or extracardiac issues)
 1 month – 85%
 1 year – 80%
 5 year – 73%
• Higher Risk
 1 month – 61%
 1 year – 20%
Fetal Intervention
• VERY small balloon catheter is inserted via mothers
abdomen, across uterus, through fetal heart across
aortic valve. Fetal aortic valvuloplasty is performed.
• Marginal success with select patients
 Must have diagnosis in early 2nd trimester
 Absence of genetic or extracardiac anomalies
 Early stage of critical aortic stenosis (LV is dilated with
some preserved function, but not yet involuted)
 Favorable maternal habitus
Comfort Care/Hospice
• Why is it a viable option in 2010?
 “The Fontan is doomed to fail.” Dr. Reddington, ACC
2003
 Fontan patients will develop protein-losing enteropathy,
ventricular dysfunction, hypoxemia, thromboembolism,
arrhythmias and liver failure.
Why Fontans Fail
As we age, the ventricular EDP rises.
In Fontan patients, the CVP must
exceed the EDP. Eventually, the EDP
will rise to an intolerable level.
Summary
• HLHS is universally lethal w/out treatment.
• A patent foramen ovale & ductus arteriosus are necessary for
survival.
• Echocardiogram is modality of choice for diagnosis.
• Management of the neonate w/HLHS is complicated: PGE is
necessary as well as ventilation/support to permit sats 75% to
85% and no acidosis.
• Transplant and staged repair are not w/out their complications
(survival for both about 70% in 5 yrs).
• Comfort care & fetal interventions are options to be considered.
• Decision-making is a TEAM effort by pt. family & medical team.
Thank You!
Questions ?