1. Chris Burke, MD

2. What is the Ductus Arteriosus?

3. Ductus Arteriosus  Allows blood from RV to bypass fetal lungs  Between the main PA (or proximal left PA) and the descending thoracic aorta  Maintains patency in utero by low O2 tension and high circulating prostaglandin levels

4. Ductus Arteriosus  During final trimester, ductus becomes much less sensitive to prostaglandins  Following birth, rise in O2 tension and lack of placental prostaglandins usually results in closure  Usually complete by 12-24 hours, but sometimes days-weeks  Becomes ligamentum arteriosum

5. Patent Ductus Arteriosum  Roughly 1 out of 1200 live births, more common in premature infants  thought to be related to immature ductal wall being less sensitive to O2 tension  Constitutes 7% of congenital heart defects  Desirable in some defects including many cyanotic heart lesions; this has led to the use of PGE4 clinically

6. Pathophysiology  Shunt volume determined by the size of ductus and ratio of pulmonary to systemic vascular resistance  PVR declines over first several weeks of life, increasing left-to-right shunt across PDA  Excessive shunting can lead to right heart failure

7. Pathophysiology  Over time, pulmonary vascular obstructive disease will develop  Eisenmenger syndrome is the end result, when shunting reverses to right-to-left; this is associated with irreversible pulmonary hypertension and cyanosis, eventually leading to RV failure

8. Morphologies

9. Clinical Manifestations  Infants with large shunt volume may develop CHF leading to tachypnea, tachycardia, and poor feeding  Physical exam findings include: widened pulse pressure and continuous “machinery murmur”, heard best along the left sternal border radiating to the back

10. Clinical Manifestations  CXR may show increased pulmonary markings and left heart enlargement  EKG may have LVH and/or left atrial enlargement  Echo  diagnostic method of choice  Diagnostic cardiac catheterization generally only performed in adults to evaluate for pulmonary hypertension

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13. Treatment  Pharmacologic  Endovascular  Surgical

14. Considerations  Closure is performed for all symptomatic patients with left-to-right shunt  Indications for closure in Asx patients:  signs of left heart volume overload  reversible pulmonary hypertension  murmur  Closure NOT recommended when Eisenmenger physiology is present or PDA is silent (controversial)

15. Considerations  In patients with PVR greater than 8 Woods Units, closure is generally not recommended  This is especially true when right-to-left or bi- direction flow is present or elevated PVR not reversed with high O2 or iNO  This can lead to catastrophic RV failure, due to loss of “pop-off” mechanism

16. Pharmacologic Closure  Indomethacin, a prostaglandin inhibitor, can be used to close a PDA  0.1-0.2 mg/kg IV at 12 or 24- hour intervals for a total of three doses  Rarely effective in term infants  80% effective in premature infants

17. Surgical Closure  Dates back to 1939  Generally reserved for infants and children with lesions deemed unsuitable for percutaneous closure  Good choice for larger PDAs (~ 8mm)  Posterolateral thoracotomy classically, but VATS approach described

19. Percutaneous Closure  First performed in 1967  Access via femoral artery or vein  Most commonly use coils or occlusion devices  Proven benefit with PDAs < 3mm  Major limitation of these techniques is ductus size  in one study a PDA diameter greater than 4mm had a 24-fold increased risk of incomplete closure  Morphology is another significant issue!

20. Percutaneous Closure

22. Surgical Closure Still Has a Role  Galal et al reported a 20% conversion or failure rate with 236 attempted percutaneous closures  Hsiao et al reported reduced number of ventilator days and improved outcomes in VLBW ( 14 days old) surgical repair

23. Management Summary  Who gets closed?  Sxs with left-to-right shunt  Audible murmur  Reversible pulmonary HTN  Left sided volume overload/heart failure

24. Management Summary  Premies  indomethacin; surgery if unsuccessful  Term infants  medical treatment to optimize for percutaneous closure; if this fails, then surgery  Children/Adults: in general, percutaneous closure