Congenital Heart Disease in Down Syndrome

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Congenital Heart Disease in Down Syndrome

• Dr Rachael Hatton
• Cardiology Clinical Meeting
• 4th Feb 2009

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Case History Baby N

• Born at 384 weeks.
• Normal vaginal delivery following an
  uncomplicated pregnancy.
• At delivery was noted to be dysmorphic.
• Long torso, short limbs. Single palmar creases,
  low set ears, moon-like facies, 3 fontanelles.
• Provisional diagnosis of Down Syndrome

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Case History Baby N

• Loud single S2. No murmur.
• Liver palpable 2 cm below costal margin.
• PDx pulmonary hypertension due to pre-birth
  asphyxia (meconium staining of the amniotic fluid)

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Day 5

• Respiratory distress.
• Tachypnoea RR 80. Occasional desaturations to 82
  on room air. 99 on oxygen.
• No accessory muscle use.
• 1/6 systolic murmur at the left lower sternal edge

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Investigations

• Chest XRay Normal
• ECG

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ECG

• Extreme left axis deviation (abnormally superior
  axis)
• No conduction disturbance

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Differential Diagnosis?

• - AV septal defect
• - Univentricular heart
• - Hypoplastic right ventricle
• Where to next?

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Echo
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Echo
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Echo
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Cardiac Embyrology
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Cardiac Embryology
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Development of the Interatrial Septum
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By day 50
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Congenital Heart Disease in Down Syndrome

• 40 of Down Syndrome newborns have one or more
  major cardiac defect
• Down Syndrome accounts for 35 of all AVSDs

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Complete AVSD - Pathology

• Large septal defect
• Common atrioventricular valve
• Regurgitation

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Complete AVSD - Pathology

• Three subtypes
• Type A frequent in Down syndrome, usually an
  isolated defect

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Clinical Manifestations

• Tachypnoea, failure to thrive
• Pulmonary hypertension
• Murmurs

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Echocardiography

• Primary diagnostic tool
• Assessment of differential diagnoses
• Assess for coexisting malformations
• Assess for ventricular imbalance

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Radiography

• Cardiomegaly
• Right atrial enlargement
• Left atrial enlargement
• Pulmonary markings

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ECG

• Prolonged PR interval
• Atrial enlargement
• Frontal axis deviation
• Ventricular hypertrophy

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Cardiac Catheterisation

• Rarely needed
• Gooseneck deformity of the LVOT on LV gram

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Down Syndrome and AVSD

• More likely to have complete AVSD and associate
  ToF.
• Extent and progression of pulmonary vascular
  changes is controversial.
• Haemodynamic assessment must incorporate
  comorbidities seen in Down Syndrome.

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Surgical Repair

• Untreated, complete AVSDs carry a poor
  prognosis.
• Surgery usually undertaken in infancy
• Patch repair and valve reconstruction

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Reoperation after Repair

• 17 during 20 years post repair
• Long-term echocardiographic monitoring is required

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Long-term outcomes Is Down Syndrome a Risk
Factor for Poor Outcome after Repair of
Congenital Heart Defects?

• Journal of Paediatrics 1998
• 3965 patients
• 289 (7) had Down Syndrome

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Long-term outcomes Is Down Syndrome a Risk
Factor for Poor Outcome after Repair of
Congenital Heart Defects?
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Long-term outcomes Is Down Syndrome a Risk
Factor for Poor Outcome after Repair of
Congenital Heart Defects?

• No significant difference for other malformations

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Long-term outcomes Is Down Syndrome a Risk
Factor for Poor Outcome after Repair of
Congenital Heart Defects?

• Age at reparative surgery younger for Down
  Syndrome patients
• Why?

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Reasons for Reoperation

• Incompetence of the LAVV
• Others

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Conduction Disturbance

• No significant difference
• Small proportion requiring PPM

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A Short Note on Genetic Counselling for Down
Syndrome

• Extra chromosome 21 vs translocational trisomy 21
• Genotype testing of the affected infant

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