This document discusses ductus arteriosus dependent congenital heart diseases. It begins by defining ductus dependent circulation as abnormalities where ductus arteriosus patency is required to maintain systemic perfusion. It then describes the anatomy and physiology of the ductus arteriosus, noting its role in diverting blood from the pulmonary to systemic circulation in fetal life. The document outlines conditions of ductus dependent pulmonary and systemic blood flow. It discusses goals of management as minimizing hypoxemia and balancing pulmonary and systemic circulations. Maintaining ductal patency with prostaglandins is emphasized as critical for stabilization in ductus dependent lesions.

1. Ductus dependent congenital heart
diseases
Dr Raghu kishore

2. Congenital heart defects with ductus-dependent
circulation are defined as abnormalities, in which the
permeability of the ductus arteriosus is mandatory in
order to maintain systemic perfusion

3. Anatomy of Ductus Arteriosus
Connects the main
pulmonary artery to
descending aorta.

4. Physiology of Ductus Arteriosus
• Carries 60% of combined
ventricular Output
• Diverts blood from high resistance
pulmonary circulation to low
resistance descending aorta and
placental circulation.
• PGE1 and PGI2 formed intra
murally and in placenta maintain
ductal patency in fetal life

5. Post Natal Closure of PDA
Functional closure
• In 15 hr., contraction of medial
smooth muscles due to ↑ PO2 & ↓
PGE1.
Anatomical closure
• In 3 wk., replacement of muscle
fibres with fibrosis creating
ligamentum arteriosus & the duct
loses the ability to reopen

6. • Cassels et al. defined the true persistence of the PDA when it persists in an
infant beyond 3 months of age.
• Takizava et al concluded that endogenous NO has a major role in
regulating the patency of the DA in earlier fetal stages, while dilator
prostaglandins may play a role in the near-term fetus

7. • The PGE1 was beneficial in opening the ductus and raising the systemic
arterial oxygen saturation in neonatal patients with duct-dependent
congenital heart defects.
• According to Mc Namara, the period of 1946 to 1982 saw the revolution
in pediatric cardiac care due to the evolution of the methods to keep
open the PFO and PDA.
• Successful medical manipulation of PDA became the routine practice
now a days .

8. Regulators of ductal patency

9. Regulators of ductal patency

10. • 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
BEFORE BIRTH AFTER BIRTH

11. DUCTUS ARTERIOSUS DEPENDENT
PULMONARY BLOOD FLOW
• Pulmonary Atresia with or without VSD
• Critical Pulmonary Stenosis
• Tricuspid atresia
• Tetralogy of Fallot (severe form)
• Severe Ebstein’s anomaly
• Severe TR

12. DUCTUS ARTERIOSUS DEPENDENT
SYSTEMIC BLOOD FLOW
• Critical aortic stenosis
• Coarctation of the aorta
• Interruption of aortic arch
• Hypoplastic left heart syndrome

13. DUCTUS ARTERIOSUS DEPENDENT
PULMONARY & SYSTEMIC
CIRCULATIONS
TWO PARALLEL CIRCULATIONS
MIXING IS NEEDED
Transposition of Great Arteries

14. Duct-dependent pulmonary Circulation
• Lungs are underperfused in these babies.
• PDA diverts partially saturated systemic blood towards the pulmonary
circulation to improve the overall saturation.
• Rarely, a widely open duct may raise the PaO2 > 49 mm Hg. Therefore, the
concentration of oxygen, to start ductal constriction, is seldom achieved by
oxygen supplementation
• PaO2 remains in the range of 35 to 40 mm Hg
• least benefitted by oxygen administration and the administration of 100
percent oxygen only increases the dissolved oxygen level.

15. OBSTRUCTION OF PULMONARY
FLOW
RVH
RIGHT ATRIAL PRESSURE ↑
SYSTEMIC CYANOSIS
PERSISTENT OPENING
FORAMEN OVALE
Resistance Blood Flow
Fails
Shunting of unoxygenated blood from
the right atrium into the left atrium

16. Duct-dependent systemic Circulation
• Obstructive left-sided lesions are responsible for the decreased perfusion to the
body leading to acidosis of the vital organs including the brain and kidney.
• The aortic stenosis leads to pressure overload of the heart.
• Clinically present with hepatomegaly and right ventricular dominance.
• The duct in such cases becomes not only a decompressing channel, but also
provides volume and perfusion pressure for the whole body.
• Echocardiographic evaluation shows characteristic reverse filling of the arch and
ascending aorta.

17. Hypoplastic left heart syndrome (HLHS)
• Leads to complete intracardiac mixing of pulmonary and
systemic venous blood and the PA is the single outlet for
the total cardiac output.
• When PVR falls in the early postnatal period, the Qp
increases at the cost of the systemic (Qs) and coronary
blood flow.
Qp & Qs mismatch
1. Excessive Qp leads to pulmonary edema and tachypnea
augments the overall metabolic rate
2. Excessive Qp results in an added volume load to the
single ventricle resulting in ventricular dysfunction and
valvular regurgitation
3. Qs falls leading to diminished oxygen delivery ,
acidosis, necrotizing enterocolitis, renal and hepatic
dysfunction and other complications

18. Effect of hypoxemia in duct-dependent CHD

19. Differential Diagnoses
• Pulmonary hypertension of the New born (PPHN)
• Neonatal Sepsis
• Metabolic disorders
• Primary lung pathology
• Obstructed TAPVC
• Methemoglobinemia
• Other disorders - choanal atresia, Pierre Robin sequence, vascular ring,
diaphragmatic hernia, acyanotic CHDs with shunt reversal, chest infections,
hypothermia and hypoglycemia.

20. Clinical presentation
• Usually coincide with the time of ductal constriction or closure .
• Often present in the first few days of life with incremental cyanosis.
• Neonatal cyanosis becomes more conspicuous due to their higher
hemoglobin levels.
• Central cyanosis is dependent on absolute concentration of deoxygenated
Hb and is more than 3 grams/L in arterial blood and more than 5 grams/L
in capillary blood.

23. Clinical presentation
• babies with higher fetal Hb level will have late visible cyanosis.
• Very sick babies usually have cyanotic spell or congestive heart failure and
circulatory collapse without clinical cyanosis.
• An inaudible murmur must not be criteria for exclusion of CHD, and some times,
the deterioration of the clinical condition with disappearance of murmur is a
pointer for an urgent intervention.
• Involvement of multiple organs like kidney, brain or skeletal system, which may
add up to the morbidity and mortality. Hence a detailed examination and parental
counseling is required.

24. What to do…?

28. Pulmonary oligemia

30. Confirmation of Cyanosis
• Central cyanosis must be confirmed by monitoring saturation with pulse
oximetry (PO) and subsequently with ABG.
• Monitor pre- and postductal oxygen saturations.
• If there is a difference of saturation in upper and lower limb of more than
3 to 7 % , the chances of having ductal flow from the pulmonary artery to
aorta are high.
• In first few hours, differential saturation may be fallacious due to high
pulmonary artery pressure and patent duct.

31. Apply hyperoxia test
• In the absence of fixed cardiac shunts, 100 percent oxygen will increase alveolar
PO2, leading to an increase in pulmonary venous and systemic arterial PO2.
• In cyanotic CHDs (e.g. decreased pulmonary blood flow or TGA), little or no rise in
PaO2 would be expected after breathing 100 percent O2.
• However, the same finding may occur in infants with significant pulmonary
hypertension, if significant right-to-left shunting persists through extrapulmonary
shunts (ductus arteriosus and foramen ovale).

33. Interpretation of the hyperoxia test

34. Validity of pulse oximetry in screening for CHD
• Ten studies (44,969 newborns,71 severe defects) evaluating the usefulness of
neonatal PO screening in timely detection of CHDs showed a high specificity
(99.99%) and the overall rate of detection of 15 individual defects with PO was 72
% (range 46-100%), exceeding that of the clinical examination, 58 % (9-86%).
• PO should be documented at preductal and postductal sites to assess for
differential or reverse differential cyanosis. If the preductal saturation is higher than
the post ductal saturation (3 to 7% difference), differential cyanosis exists.
• In Sweden the use of PO and clinical examination led to an increased sensitivity of
82.8 % and specificity of 100 % for the duct dependent lesions

36. Goals of management
• To establish the diagnosis after initial stabilization or
resuscitation
• Intubation whenever indicated
• To minimize hypoxemia
• Ensure balance between Qp & Qs

39. When there is doubt…..?
BLUE BABY BABY IN SHOCK
START PROSTAGLANDIN

40. PGE1 infusion

41. Adverse effects of Prostaglandins

42. • Increase the FiO2 once ductal patency is maintained.
• Do not try to achieve complete abolition of cyanosis
• A saturation of 75 to 85 % can be adequate to avoid tissue hypoxemia and
eventual lactic acidosis
• PCO2 levels should be optimized between 35 to 45 mm Hg, with or
without ventilation
• Give IV fluids, blood transfusion, address the underlying cause for acidosis

43. Ductal stenting - Advantages
1. Eliminating the need for neonatal palliative surgery.
2. Reducing the number of operations required.
3. Optimizing the time of definitive surgical correction.
4. High-flexibility coronary stent is an effective alternative in
high-risk surgical candidates

44. Procedure of PDA stenting
• Under GA
• Antegrade through FV or retrogtade through FA
• 4F Mullin sheeth
• Coronary stent on 0.14 wire
• Ensure to cover whole length especially PA end
• After dilatation with balloon may be done
• Asprin 1-3mg/kg as long as duct patency required

47. D-TGA Non surgical options
• Key is to ensure
mixing
• Fluid boluses
• PGE1

48. Balloon atrial septostomy

50. Bioengineering in duct patency
• Transfection is the delivery of DNA, RNA, proteins, and macromolecules into the
eukaryotic cells.
• A protein called fibronectin, the concentration of which increases in the advanced
stage of gestation, is responsible for closure of the duct.
• The gene for a fibronectin decoy was introduced directly in utero in the ductal
tissue to keep ductal patency in animal experiments.
• Percutaneous postnatal transfection of gene for PG in ductal tissue also ensured
prolonged patency of duct.
• These and several other projects are underway to get the safest technique to keep
duct open.

51. The key to successful outcomes in duct
dependent lesions is……
to realize that the patient IS duct
dependent…….!!
Thank you