Download ductus arteriosus dependent congenital heart disease

Ductus Arteriosus Dependent
Congenital Heart Disease
Amjad Kouatli MD. FAAP. FACC.
Consultant Pediatric Cardiologist
King Faisal Specialist Hospital and Research Center
Jeddah
Anatomy of Ductus Arteriosus
• Large channel found in
mammalian fetuses.
• Connects the main
pulmonary artery to
descending aorta.
• Its media consists mainly
of smooth muscles
compared to elastic fibres
in MPA, DAO.
Physiology of Ductus Arteriosus
• Carries 60% of combined
vent. output
• Diverts blood from high
resistance pulmonary
circulation to low resistance
descending aorta and
placental circulation.
• PGE1 and PGI2 formed
intramurally and in placenta
maintain ductal patency
in fetal life
Post Natal Closure of PDA
• Functional closure
In 12 hr., contraction of
medial smooth muscles
due to  PO2 &  PGE1.
• Anatomical closure
In 3 wk., replacement of
muscle fibres with fibrosis
creating ligamentum arteriosus.
• Silent without hemodynamic
compromise to either pulmonary
or systemic circulation
Before
Birth
After
Birth
If ductal closure causes significant decrease in
systemic circulation, the condition is called
ductus dependent systemic blood flow
If ductal closure causes significant decrease in
pulmonary circulation, the condition is called
ductus dependent pulmonary blood flow
DUCTUS ARTERIOSUS DEPENDENT
SYSTEMIC BLOOD FLOW
Lesions characterized by the entire or part of
the systemic blood flow depends solely on
the patency of the ductus arteriosus.
– Coarctation of Aorta (severe)
– Interrupted Aortic Arch
– Hypoplastic Left Heart
Critical Coarctation
Interrupted Aortic Arch
IAA between LCC, LSC
Hypoplastic Left Heart
Clinical Presentation
• Normal birth weight and initial examination
• Symptoms start suddenly when the duct closes.
• 40% are symptomatic first 2 days of life.
• Tachypnea, dyspnea, grunting, flaring, ashen
colour, and cyanosis.
• Hyperactive precordium, tachycardia, hypotension,
weak or absent femoral pulses, single S2,
systolic heart murmur.
Investigations
• Laboratory
Metabolic acidosis,
hypoglycemia
hyperkalemia.
• ECG: RAD, RVH
• Chest X ray:
mild cardiomegaly
mild to severe
increased pulmonary vascular markings.
Echocardiogram
Aortic Atresia
Hypoplastic LV
Echocardiogram
Interrupted Aortic Arch
Critical Coarctation
DUCTUS ARTERIOSUS DEPENDENT
PULMONARY BLOOD FLOW
• Hypoxic lesions characterized by the
pulmonary blood flow depends solely on
the patency of the ductus arteriosus.
– Pulmonary atresia
– Severe pulmonary stenosis
– TOF with severe pulmonary stenosis
TOF Critical PS
Pulmonary Atresia
Clinical Presentation
• Normal birth weight and initial examination
• Symptoms start suddenly when the duct
closes.
• Progressive cyanosis, tachypnea.
• Hyperactive precordium, tachycardia, single
S2, TR systolic murmur, normal pulses.
Investigations
• Laboratory
hypoxemia not responding to O2
hypocarbia (hyperventilation).
• ECG:
LAD, LVH .
• Chest X ray;
mild to severe cardiomegaly,
decrease in pulmonary
vascular markings.
Echocardiogram
Critical Pulmonary Stenosis
Pulmonary Atresia
Intact ventricular septum
Hypoplastic RV
Treatment
Prostaglandin E1
• IV via a large vein, 0.05- 0.1 ug/kg/min
• Side effects: apnea 10%, hypotension,
inhibition of platelets aggregation, fever,
diarrhea, flushing, bradycardia, seizures,
arrhythmia.
• Therapeutic response is judged
– Femoral pulses restoration, pH in DDSBF
– Resolved cyanosis in DDPBF
Treatment cont.
• Correction of metabolic acidosis with sodium
bicarbonate, acidosis decreases actin and
myosin coupling.
• Correction of hypoglycemia and hypothermia.
• Surgical or transcatheter intervention:
Palliation:
Complete correction:
HLHS
Norwood
Hybrid
PA-IVS
BT Shunt
PDA Stent
Treatment cont.
Cardiac Catheterization
For balloon valvuloplasty in critical PS
RV injection, AP view
Critical PS, Severe TR
RV hypertrophy
RV injection, lateral view
PV annulus 4.4 mm
Effective opening < 1 mm
0.014 wire crossed
Pulmonary valve
Balloon inflated
Waist is visible
Balloon inflated
Waist disappeared
Pre Balloon dilatation
Decreased pulmonary blood flow
RA dilatation
After Balloon dilatation
More blood to lungs
Decreased RA size
Treatment cont.
Oxygenation, Ventilation
• Oxygen and hyperventilation are excellent
pulmonary vasodilator leading to decrease
pulmonary vascular resistance.
• Hypo oxygenate and hypo ventilate in ductus
dependent systemic blood flow.
• Oxygenate and ventilate in ductus
dependent pulmonary blood flow.
Effect of oxygen on pulmonary and systemic circulation.
Oxygen decreases PVR
5
2.5
2
5
2.5 10
2.5
5
100%
80 %
4
10
4
92 %
5
8
100%
100%
5
2
60%
60%
PVR = SVR
PVR  SVR
2
60%
Summary
• Ductus dependent congenital heart disease
should be considered in every newborn
– presenting with shock or cyanosis
– physical examination shows hyperactive
precordium, heart murmur, or weak pulses
• Prognosis improves dramatically with early
diagnosis, early infusion of Prostaglandin and
early understanding of the disease physiology