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Patent Ductus Arteriosus. Seoul National University Hospital Department of Thoracic & Cardiovascular Surgery. Patent Ductus Arteriosus. 1. Definition An open communication usually between upper descending aorta and proximal portion of left pulmonary
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Patent Ductus Arteriosus Seoul National University Hospital Department of Thoracic & Cardiovascular Surgery
Patent Ductus Arteriosus • 1. Definition • An open communication usually between upper • descending aorta and proximal portion of left pulmonary • artery and is the result of persistent patency of fetal • ductus arteriosus • 2. History • * Galen : 1st description(Born in AD131) • * Gibson : Continuous murmur in 1900 • * John Strieder : Attempted to close in 1937 • * Robert E. Gross : Successful ligation in 1938 • * Rashkind & Cuaso : Catheter closure in 1977
Pathophysiology of PDA • Left-to-right shunt from the thoracic aorta to the pulmonary artery leads to augmented pulmonary blood flow, pulmonary hypertension, and congestive heart failure. • Demonstrating blood from across the ductus with associated left ventricular hypertrophy and left atrial enlargement and comprises 12~15% of congenital heart defects
Anatomy of Ductus Arteriosus • 1. Position • * Unilateral • * Bilateral • * Absence ( 35-40% in TOF ) • 2. Histology of PDA • * Thick intima with unfragmented elastic lamina • * Media contains mucoid material with spiral muscular • intricate helicoid arrangement and elastic material • 3. PDA as a coexisting anomaly • * Orientation of ductus to aortic arch varies
Morphology of Ductus Arteriosus • 1. At birth • * Resembles a muscular artery • * Intima : intact wavy internal elastic lamina, split up • into several layers and interrupted • underneath intimal cushion • * Media : mainly circular smooth muscle cells with • minimal elastic fibers ( mucoid lake ) • 2. Anatomic closure • * Necrosis of cellular component of the media and • diffuse fibrous proliferation of intima • 3. Aneurysms of ductus arteriosus • * Spontaneous infantile form • * Childhood or adult form
PDA PDA
Postnatal Closure of Ductus Arteriosus • 1. First Stage ( Functional closure ) • * Within 10~15 hours after birth ( contraction of smooth muscle • & approximation of intimal cushion ) • 2. Second Stage (Anatomic closure ) • * Completed by 2~3weeks ( fibrous proliferation of intima, • necrosis of media, hemorrhage in the wall and sealing of • the lumen ) • * Ductus arteriosus is closed by 8 weeks in 88% • 3. Physiology • * Vasoactive substances ( acetylcholine, bradykinin, endogenous • catecholamine and others ) by variations in PH, but chiefly by • 02 tension and prostaglandins ( PGE1, PGE2, prostacyclin, • PGI2 )
Natural History of PDA • 1. Incidence • * Isolated PDA : 1/2000 birth, 5-10% of CHD • * Sex ratio ; male : female = 1 : 2 • 2. Spontaneous closure • * 0.6% of patients per year. ( 20% by age of 60 ) • * Uncommon over 3~5 months of age ( full term baby ) • 3. Death • * Untreated large PDA is high in infancy ( 30%) • * 42% of patients with PDA will die by age of 45 • 4. Mode of Death • * CHF in infancy • * CHF by 2nd or 3rd decade in large PDA ( PVR ) • * CHF 3rd or 4th decade in moderate PDA • * Rare SBE
Clinical Features of PDA • 1. Large PDA • * Severe congestive heart failure within a month • * Tachypnea, sweating, irritability, poor feeding, • 2. Moderate PDA • * Large shunt from the 2nd or 3rd months of age • * Compensatory LVH with improvement & stabilization • 3. Small PDA • * Symptoms are absent in infancy and childhood • * Continuous murmur • 4. Silent PDA • * Controversial in surgical treatment
Operation of PDA • 1. Indication • 1) Large PDA is indicated beyond the 1st month of life, but • symptoms of heart failure is present, surgery is indicated • 2) In the absence of symptom, operation delayed until • the age of about 6 months • 2. Contraindication :severe pulmonary vascular disease • 3. Technique of operation • 1) Division :divided rather than ligation • 2) Ligation : In neonate or some infant • 3) Closure of PDA in older adults • * Using CPB (calcified aortic end, short ductus, PH) • 4. Percutaneous closure ( Rashkind, Amplatzer, Coil ) • 5. Thoracoscopic closure
Anatomy of PDA • PDA as visualized from a left anterior oblique view
Operative Exposure of PDA • PDA through a left thoracotomy & the mediastinal pleura • is opened and reflected anteriorly and posteriorly
Median Approach of PDA • Closure of PDA from a median sternotomy approach
Thoracoscopic Surgery (VATS) • Indications Isolated PDA associated with or without other minor cardiac lesions • Contraindications Complex congenital defects requiring CPB Ductus diameter larger than 9 mm Calcification of ductus Pleural adhesion or right aortic arch
Thoracoscopic Surgery (VATS) • Why VATS PDA ligation -- Potential thoracotomy morbidity Long-term post-thoracotomy pain Postoperative pulmonary complication Thoracic scoliosis -- VATS PDA ligation Decrease chest wall trauma Minimize nerve injury & rupture of intercostal ligament Cosmetic effect Painless
PDA Ligation by VATs • An endoscopic vascular clip is placed to interrupt • the patent ductus arteriosus. The arrow denotes • the recurrent laryngeal nerve
Operative Results of PDA 1) Mortality 2) Incremental risk factors for early death * old age • * pulmonary vascular disease • 3) Survival • 4) Symptomatic and functional status • 5) Physical development • 6) Recurrence • 7) False aneurysm • 8) Vocal cord paralysis 9) Phrenic nerve paralysis 10) Chylothorax
Management of Pre-term PDA • General management Fluid restriction Ventilatory support Correction of anemia Correction of metabolic acidosis Diuretics; lasix decrease ECF volume, but increase prostaglandin production • Indomethacin • Other cyclooxygenase inhibitor Ibuprofen Mefenamic acid • Surgical treatment
PDA in Pre-term Baby (1) 1. Incidence • Increase with decreasing gestational age & birth weight, • but hemodynamic significancy is less. • 28 ~ 30wks : 77% Wt under 1000gr : 40% • 31 ~ 33wks : 44% Wt under 1750gr : 10% • 34 ~ 36wks : 21% • 2. Operative indications • Failure of indomethacin trial • Respiratory distress • Necrotizing enterocolitis • Intracranial hemorrhage
PDA in Pre-term Baby (2) • 3. Operative results • Early mortality : 10~30% • Respiratory distress • Intracranial hemorrhage • Diffuse coagulopathy • Late : BPD in 1/3 of survivor • Complications (CP, retrolental fibroplasia) • in 1/6 of survivor