Hypoplastic Left Heart Syndrome (and the single ventricle repair)

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Hypoplastic Left Heart Syndrome (and the single
ventricle repair)

• Henaro Sabino, MD
• Sibley Heart Center Cardiology at Childrens
  Healthcare of Atlanta Emory University

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CHEST PAIN, SYNCOPE

• IM COMIN HOME!

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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.

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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).

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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

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1980s
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Xenotransplantation, Baby Fae

• Dr. Leonard Bailey, Loma Linda University Medical
  Center, November 1984.
• http//www.babyfae.com

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Anatomy
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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.

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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.

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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

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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

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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!)

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Positive Hyperoxitest

• Seriously consider initiation of prostaglandin
  (PGE) at a low dose (0.03 mcg/kg/min) until
  diagnosis is confirmed.

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Initial Assessment

• ALWAYS
• A - Airway
• B - breathing
• C circulation
• CXR and ECG usually not very helpful in Dx.

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Physical Findings

• Comfortable or in distress?
• Cyanosis w/out respiratory distress is cardiac
  until proven otherwise
• Active or lethargic?
• Cyanosis?
• Degree - saturation usually lt85 to be seen
• Anemia makes cyanosis difficult to notice
• Pallor
• Vasoconstriction from circulatory shock
• Perfusion and Peripheral pulses
• End organs (i.e. watch UOP)

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Respiratory Status

• Tachypnea but with minimal distresscardiac until
  proven otherwise.

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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

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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

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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

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Arterial Blood Gases

• In congenital heart disease typically
• Compensated or partially compensated metabolic
  acidosis
• Arterial PO2 usually low lt50 with cyanotic heart
  diseasebut not always
• If PCO2 is rising, think respiratory failure - be
  ready to intubate!

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Blood Gases
Arterial Capillary Venous
PH accurate accurate lower PO2 accurate invari
able lower PCO2 accurate accurate higher HCO3
(calculated) accurate accurate accurate
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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

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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.

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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

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Prostaglandins continued

• Side effects -
• Apnea - be prepared to intubate
• Fever
• Hypotension - have volume and inotropes available
• Flushing

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Access

• Umbilical is preferred in a newborn
• UVC even if in suboptimal position
• UAC
• PIC line
• PIV
• AVOID groin line if possible

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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.

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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)

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Metabolic Acidosis

• Treat metabolic acidosis aggressively (base
  deficit lt -3)
• 1 meq/kg Na bicarbonate
• Repeat blood gas

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Other Systems

• Renal function
• Urine output
• BUN/Cr
• Renal ultrasound
• Head ultrasound
• Liver function tests
• Coagulopathy

• Thrombocytopenia
• R/O sepsis
• Genetics

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Fetal Diagnosis
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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

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HLHS
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NORMAL FETAL 4-CHAMBER
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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.

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Case Presentation

• Airway-Breathing-Circulation
• Respiratory rate (60-90 bpm)
• Work of breathing (no retractions)
• Saturations (80)
• Warm extremities good cap refill

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Case Presentation

• No obvious dysmorphic features.
• More Cardiac Exam Findings
• No murmur.
• Single second heart sound (S2).
• Hyperdynamic precordium.

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Case Presentation

• Urgent Cardiology Consult
• 404-256-2593!!
• Cardiac History Physical
• Echocardiogram

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Echocardiogram HLHS
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Hypoplastic Left Heart Syndrome
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Case Presentation

• BUT
• No beds available at Egleston immediately
• Need to manage infant for 24 hours before
  transport
• NOW what do we do?

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Case Presentation

• Intravenous access
• UVC (double lumen)
• UAC
• PIV
• PIC
• Remember AVOID groin lines

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Case Presentation

• Prostaglandins
• 0.03 mcg/kg/min
• Side effects
• Apnea
• Options ?
• Intubate vs nasal cannula air

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Case Presentation

• Labs
• Arterial (or venous) blood gas
• Electrolytes (normalize)
• CBC
• LFT
• Genetics
• Lactic acid
• Head and Renal ultrasound
• ECHO/EKG

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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

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Blood Pressure

• Blood pressure - systolic and diastolic blood
  pressures are equally importantnot just mean!!
• Coronary flow to heart dependant on diastolic BP

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Case Presentation

• Saturations 95
• pO2 50
• Decreased urine output
• Metabolic acidosis
• Rising lactic acid
• Whats going on?!?

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Chest X-Ray
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Case Presentation

• Pulmonary Over Circulation with systemic
  compromise
• Intubate/hypoventilate
• CO2

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Hypoplastic Left Heart Syndrome
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Case Presentation

• Y- tube Physiology

To Body
To Lungs
Pulmonary Resistance Lowered by - Oxygen -
Prostaglandin - Resp alkalosis Raised by -
PPV - Hypoxia - Resp acidosis
Systemic Resistance Raised by - Dopamine -
Epinephrine
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Monitoring Innovations

• Lactic Acid
• Mixed venous oxygen saturation
• Near infrared spectroscopy

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Pulmonary Atresia
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Hypoplastic RIGHT Heart
Flow begets growth
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Same Y-tube Physiology
To Body
To Lungs
But now not enough blood flow to lungs
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Ideal Saturation for PDA-dependant

• For balanced amount of blood flow to both the
  lungs and the body in a single ventricle (i.e.
  Y-tube physiology infant) is
• 75 to 85 oxygen saturation
• (in upper extremity)

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Options for HLHS in 2010

• Comfort Care
• Transplant
• 3-Stage Palliative Repair
• Fetal Intervention

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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.

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HLHS Palliative Repair

• HLHS (sats 80s)
• Norwood repair in 2wks
• - Provide systemic BF
• - Balance pulmonary BF
• Glenn repair (SVC to PA)
• - More pulmonary BF
• Fontan repair (IVC to PA)
• - Relieve volume load to RV
• - Venous blood totally bypasses heart (sats 100)

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Norwood (Stage I)
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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

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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

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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.

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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.
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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.

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Thank You!
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Questions ?