Ductus-Dependent Circulation
Ductus-Dependent Circulation
Q1. Which of the following is an example of ductus-dependent systemic circulation?
Q2. Closure of ductus arteriosus in a pulmonary atresia baby leads to:
Q3. Which drug is lifesaving in ductus-dependent CHD?
Q4. Ductus-dependent systemic circulation lesions typically present with:
Q5. Transposition of great arteries with intact septum is ductus-dependent for:
Q6. Which of the following is NOT ductus-dependent?
Q7. Clinical deterioration in ductus-dependent lesions usually occurs:
Q8. Which prostaglandin side effect is most important in neonates?
Q9. Which lesion is ductus-dependent for pulmonary circulation?
Q10. In HLHS, ductal closure causes:
Q11. First-line stabilization in suspected ductus-dependent CHD is:
Q12. Which condition is ductus-dependent for systemic flow?
Q13. Which finding suggests ductus-dependent systemic lesion?
Q14. Which CHD may present with severe cyanosis soon after ductal closure?
Q15. Which drug closes ductus arteriosus and must be avoided here?
Q16. Which of the following is a ductus-dependent mixing lesion?
Q17. Prostaglandin infusion is started at:
Q18. Ductus-dependent pulmonary lesions present mainly with:
Q19. Which of the following is TRUE?
Q20. A neonate collapses 2 days after birth with severe shock, mottling, and absent femoral pulses. Most likely diagnosis?
The ductus arteriosus is a vital fetal vascular connection between the pulmonary artery and descending aorta.
In utero, it shunts blood away from the lungs (high resistance) toward systemic circulation.
After birth, as pulmonary vascular resistance falls and oxygen rises, the ductus normally constricts within hours to days.
However, in certain congenital heart diseases (CHDs), survival depends on ductal patency.
🔹 Types of Ductus-Dependent Circulations
1. Ductus-Dependent Systemic Circulation
- The ductus provides systemic blood flow (aorta supplied from pulmonary artery).
- Closure leads to shock, acidosis, weak pulses, collapse.
- Examples:
- Hypoplastic Left Heart Syndrome (HLHS)
- Critical Aortic Stenosis
- Interrupted Aortic Arch
- Coarctation of Aorta (critical)
2. Ductus-Dependent Pulmonary Circulation
- The ductus provides pulmonary blood flow (pulmonary artery supplied from aorta).
- Closure leads to severe cyanosis, hypoxemia, acidosis.
- Examples:
- Pulmonary Atresia
- Critical Pulmonary Stenosis
- Tricuspid Atresia
- Tetralogy of Fallot with severe RVOTO
3. Ductus-Dependent Mixing Circulation
- Ductus is required for adequate mixing of systemic & pulmonary blood.
- Examples:
- Transposition of Great Arteries (TGA) with intact septum
⚠️ Clinical Presentation
- Severe cyanosis (if pulmonary flow dependent)
- Cardiogenic shock, poor perfusion (if systemic flow dependent)
- Collapsed infant after ductal closure (24–48 hrs after birth)
- Differential diagnosis: cyanotic vs shock presentations
💊 Management
- Prostaglandin E1 (PGE1, alprostadil) infusion → keeps ductus open
- Dose: 0.05–0.1 µg/kg/min IV (then titrate to lowest effective dose)
- Side effects: apnea, hypotension, fever, flushing, seizures
- Supportive care: ventilation, fluids, correction of acidosis
- Definitive therapy: surgery or catheter-based palliation
📊 Quick Comparison Table
| Type of dependence | Examples | Effect of ductal closure | Clinical clue |
|---|---|---|---|
| Systemic | HLHS, critical AS, IAA, CoA | Shock, poor pulses | Gray, mottled baby |
| Pulmonary | PA, critical PS, TOF, TA | Severe cyanosis | “Blue” baby |
| Mixing | TGA with intact septum | Severe cyanosis | Cyanosis refractory to O₂ |
✅ In summary: Ductus-dependent circulation = CHDs where neonatal survival depends on keeping the ductus arteriosus patent until definitive repair or palliation.
| # | Key Point | Explanation |
|---|---|---|
| 1 | Definition | CHDs where neonatal survival depends on keeping the ductus arteriosus open. |
| 2 | Ductus role | Connects pulmonary artery to descending aorta in fetal life. |
| 3 | Closure timing | Usually begins within 24–48 hrs after birth → critical for presentation. |
| 4 | Systemic dependent lesions | HLHS, critical AS, interrupted aortic arch, critical coarctation. |
| 5 | Pulmonary dependent lesions | Pulmonary atresia, critical PS, tricuspid atresia, severe TOF. |
| 6 | Mixing dependent lesions | TGA with intact septum. |
| 7 | Systemic closure effect | Shock, weak/absent pulses, metabolic acidosis, collapse. |
| 8 | Pulmonary closure effect | Severe cyanosis, hypoxemia refractory to O₂. |
| 9 | Mixing closure effect | Inadequate mixing → profound cyanosis. |
| 10 | Clinical onset | Typically 1–2 days after birth (as ductus closes). |
| 11 | Presentation clue | Cyanosis → pulmonary/mixing; shock → systemic lesions. |
| 12 | Physical exam systemic | Mottled skin, poor pulses, weak femorals, acidosis. |
| 13 | Physical exam pulmonary | “Blue baby,” severe hypoxemia, relatively preserved pulses. |
| 14 | Diagnostic tool | Echocardiography confirms ductus dependency and anatomy. |
| 15 | Lifesaving therapy | Prostaglandin E1 infusion to reopen/maintain ductus. |
| 16 | PGE1 dose | Start at 0.05–0.1 µg/kg/min IV infusion. |
| 17 | PGE1 side effects | Apnea, hypotension, fever, flushing, seizures. |
| 18 | Contraindicated drug | Indomethacin → promotes ductal closure. |
| 19 | Definitive therapy | Surgical or catheter-based palliation/repair once stabilized. |
| 20 | Mnemonic | “S.P.M.” → Systemic, Pulmonary, Mixing → 3 types of ductus dependency. |
Q1. Ductus-dependent systemic circulation is seen in:
Q2. A neonate presents with severe cyanosis 36 hours after birth. Which lesion is most likely?
Q3. Which drug keeps ductus arteriosus open?
Q4. Critical coarctation of aorta is ductus-dependent for:
Q5. TGA with intact septum is dependent on ductus for:
Q6. Typical time of clinical deterioration in ductus-dependent CHD is:
Q7. A ductus-dependent pulmonary lesion causes:
Q8. Which lesion is NOT ductus-dependent?
Q9. The first-line emergency management in suspected ductus-dependent lesion is:
Q10. Which is a common complication of prostaglandin E1 infusion?
Q11. Which lesion causes systemic collapse if ductus closes?
Q12. Which drug must be avoided in ductus-dependent CHD?
Q13. Critical pulmonary stenosis is ductus-dependent for:
Q14. Which lesion is ductus-dependent mixing lesion?
Q15. Dose of PGE1 infusion in neonates:
Q16. In systemic ductus-dependent lesions, which feature is most prominent?
Q17. What is the hallmark presentation of ductus-dependent pulmonary lesions?
Q18. Which of the following is a systemic ductus-dependent lesion?
Q19. Which therapy is definitive for ductus-dependent lesions?
Q20. A neonate collapses 2 days after birth with mottling, shock, absent femoral pulses. Likely lesion?
Short Q&A on Ductus-Dependent Circulation
Q1. What is ductus-dependent circulation?
A congenital heart disease condition in which systemic or pulmonary circulation depends on a patent ductus arteriosus for survival.
Q2. Which drug is used to keep the ductus arteriosus open?
Prostaglandin E1 (Alprostadil).
Q3. What happens when the ductus closes in systemic-dependent lesions?
Severe shock, metabolic acidosis, and collapse due to loss of systemic blood flow.
Q4. What happens when the ductus closes in pulmonary-dependent lesions?
Severe cyanosis due to loss of pulmonary blood flow.
Q5. Give two examples of systemic ductus-dependent lesions.
- Hypoplastic left heart syndrome (HLHS)
- Critical coarctation of the aorta
Q6. Give two examples of pulmonary ductus-dependent lesions.
- Pulmonary atresia
- Critical pulmonary stenosis
Q7. Give an example of a mixing ductus-dependent lesion.
Transposition of the Great Arteries (TGA).
Q8. What is the initial emergency management of suspected ductus-dependent CHD?
Start Prostaglandin E1 infusion immediately.
Q9. What is the starting dose of Prostaglandin E1 (PGE1)?
0.05–0.1 µg/kg/min IV infusion.
Q10. Name a common side effect of PGE1 infusion.
Apnea.
Q11. Which drug is used to close the ductus arteriosus?
Indomethacin or Ibuprofen.
Q12. What clinical clue suggests systemic ductus dependence?
Weak pulses, shock, and metabolic acidosis.
Q13. What clinical clue suggests pulmonary ductus dependence?
Profound cyanosis with minimal improvement in oxygen.
Q14. How does oxygen therapy affect pulmonary ductus-dependent lesions?
Minimal effect on cyanosis (does not improve significantly).
Q15. What is the definitive treatment for ductus-dependent CHD?
Surgical or catheter-based correction/palliation.
Q16. Why does ductus closure typically occur after birth?
Falling prostaglandin levels and rising oxygen tension.
Q17. What is the usual age of presentation for ductus-dependent CHD?
Within the first few days after birth, often after ductus closure (24–72 hours).
Q18. Which investigation confirms ductus-dependent circulation?
Echocardiography.
Q19. What is the mnemonic “SPM” for ductus-dependent lesions?
Systemic, Pulmonary, Mixing types.
Q20. Why is early recognition of ductus-dependent lesions critical?
Delay can result in shock, metabolic acidosis, multiorgan failure, and death.
