1. PERSISTANT DUCTUS ARTERIOSUS Lourdes Asiain M.D. October 2004

2. PERSISTENT DUCTUS ARTERIOSUS Definition: Ductus arteriosus is a vessel that connects the pulmonary artery and aorta. Failure of closure and continued patency of fetal channel is termed PERSISENT DUCTUS ARTERIOSUS (PDA)

3. HISTOLOGY Circumferential Increased mucoid Substance in Intima Smooth Muscle Extracel matrix Cylindrical layers Spiral in opposing Directons

4. PDA In the fetus, the ductus diverts blood flow from the pulmonary circulation (high resistance) to the descending aorta. An Increase in PaO2 constricts the ductus. Other factors, such as the release of vasoactive substances, contribute to the closure Balance between constricting/relaxing substances

5. Factors Influencing closure of duct Contractile Apparatus Increased Pa Oxygen Absent Or reduced (asphyxia, high Altitude) Relaxant influences Prostaglandins Unresponsive Or deficient (prematurity, Genetic)

6. PDA In full term healthy newborns, functional closure occurs in 50% by 24 hrs of age, in 90% by 48 hrs. The effects of oxygen and prostaglandins vary at different gestational ages.  Oxygen has less of a constricting effect with decreasing gestational age  Indomethacin constricts the immature ductus more than the term ductus

7. PDA Factors assoc with increased incidence Prematurity RDS Fluid overload Asphyxia

8. PDA: Factors that increase incidence Prematurity: Inversely related to gestational age Found in approx. 45% of infants <1750gm 80% of infants <1000gm

9. PDA: Factors that increase incidence RDS Correlated with severity of RDS. After surfactant treatment increased risk of clinically symptomatic PDA

10. PDA Factors associated with decreased incidence Antenatal steroid administration IUGR Prolonged rupture of membranes

11. Clinical Signs The clinical features assoc with L to R shunt depend on the magnitude of shunt and the ability to handle extra volume. Shunt: magnitude and direction related to vessel diameter and pressure gradient between A and PA.

12. PDA: Clinical Signs Murmur Hyperactive precordium Bounding peripheral pulses Increase in pulse pressure Hypotension Respiratory deterioration

13. PDA: Management Ventilatory support Fluid restriction Maintain hematocrit Non surgical: Indomethacin (PGE1 inhib) Ibuprofen Transcatheter Surgical: Ligation

14. PDA: Indomethacin Prophylactic: 0.1mg/kg/dose q 24 hrs for 6 days Symptomatic: 1 st 0.2mg/kg0.2mg/Kg 2 nd 0.1mg/kg0.2mg/kg 3rd 0.1mg/kg0.2mg/kg Dose <1250gm < 7 days >1250gm > 7 days Prolonged: 4 th,5 th and 6 th dose at 24 hr intervals

15. PDA: Indomethacin Complications: Renal: decreased GFR GI Bleeding Platelet dysfunction Contraindicated if Creatinine >1.7mg, if patient is septic or if NEC present

16. Complications of PDA CHF Pulmonary hypertension Aneurysm of duct (rare) Thromboembolism (rare)

17. Conclusions Common in preterm infants Initial presentation usually DOL 1-4, Cardiopulmonary signs: murmur, bounding pulses, hyperactive precordium, resp deterioration. Management: surgical non surgical

18. References NeoFax 2004.17 th edition.Thomas E. Young, MD and Barry Mangum. Neonatology 5 th edition.2004. Tricia Lacy Gomella. Avery’s diseases of the Newborn. Taeusch et Ballard.