PDA

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PDA

  1. 1. Patent DuctusArteriousus<br />
  2. 2. History <br />In 1593 GiambattistaCarcano described ductusarteriosus in book “great cardiac vessels of the fetus”<br />Leo bottani falsely associated with “ ductus”<br />
  3. 3.
  4. 4. Anatomy <br />Normal fetal vascular channel between aorta and pulmonary artery.<br />The pulmonary end is located to left of bifurcation of pulmonary trunk<br />Aortic end is just beyond the origin of left subclavian artery<br />With a right aortic arch, the ductusarteriosus may be on the right, joining the right pulmonary artery and the right aortic arch just distal to the right subclavian artery<br />
  5. 5. Introduction <br />
  6. 6.
  7. 7. microscopic structure of the ductusarteriosus differs<br />the media of the ductusarteriosus consist largely of layers of smooth muscle arranged spirally in both leftward and rightward directions <br />The intimal layer of the ductusarteriosus is thicker than that of the adjoining arteries and contains an increased amount of mucoid substance<br />
  8. 8. Embryology <br />
  9. 9. Physiology <br />Role in the Fetus<br />6 weeks of gestation, the ductusarteriosus is developed sufficiently to carry most of the right ventricular output<br />The right ventricle ejects about two thirds of combined ventricular output<br />ductusarteriosus permits flow to be diverted away from the high-resistance pulmonary circulation <br />
  10. 10. Normal Postnatal Closure<br />closure of the ductusarteriosus is effected in two phases<br />Immediately after birth, contraction and cellular migration of the medial smooth muscle in the wall of the ductus<br />resulting in functional closure <br />commonly occurs within 12 hours after birth <br />
  11. 11. Normal Postnatal Closure<br />The second stage usually is completed by 2 to 3 weeks<br />produced by infolding of the endothelium, disruption and fragmentation of the internal elastic lamina<br />replacement of muscle fibers with fibrosis <br />permanent sealing of the lumen to produce the ligamentumarteriosum<br />
  12. 12. mechanisms responsible for the initial postnatal closure of the ductusarteriosus are not fully understood<br />increase in pO2, as occurs with ventilation after birth, constricts the ductusarteriosus<br />prostaglandins play an active role in maintaining the ductusarteriosus in a dilated state<br />PGE1, PGE2, and PGI2 dilate isolated ductusarteriosus strips or rings from term fetal lambs <br />
  13. 13. At birth, the placental source is removed, and the marked increase in pulmonary blood flow allows effective removal of circulating PGE2<br />
  14. 14. INCIDENCE OF PDA<br /> increased dramatically over the last two decades<br /> improved survival rate of premature infants<br />incidence is approximately 0.02 to 0.04 percent among term infants born at sea level<br />slight female predominance<br /> incidence is as high as 60 percent in infants born before 28 weeks gestation<br />
  15. 15. Clinical History <br />The diagnosis of PDA canot be made at birth<br />The murmur emerges after few days as the pulmonary vascular resistance falls<br />History of prematurity is very important.<br />Premature babies with respiratory distress tend to have large shunts<br />PDA is moe common in females with a ratio of 2:1<br />
  16. 16. Family history is important , as it tends to recur in siblings<br />Rubella infection to mother during the first trimester is a common cause<br /> maternal coxsackie virus infection is another cause<br />Low birth weight is common, even in small shunts<br />More common in children born in October to January<br />
  17. 17.
  18. 18.
  19. 19.
  20. 20. Another interesting point is the relation to the altitude the patient was born<br />
  21. 21. Small DuctusArteriosus<br />the resistance to flow across the ductusarteriosus is high<br />only a small left-to-right shunt develops<br />Pulmonary blood flow is increased only minimally<br />left ventricular failure does not occur<br />Most of the infants are asymptomatic<br />Murmur is detected on routine physical examination.<br />
  22. 22. Moderate DuctusArteriosus<br />In infants a moderate shunt produces symptoms of heart failure<br />Poor feeding, irritability, and tachypnea are present<br />symptoms ordinarily increase until about the second to third month <br />
  23. 23. Large DuctusArteriosus<br />Infants with a large PDA are invariably symptomatic<br />They are irritable, feed poorly, fail to gain weight and sweat excessively<br />They have increased respiratory effort and respiratory rates<br />prone to develop recurrent upper respiratory infections and pneumonia<br />symptoms indicative of severe left ventricular failure with pulmonary edema may occur early in infancy<br />
  24. 24. Patients with reversed shunt<br />Small number of cases<br />High pulmonary vascular resistance, from infancy<br />Effort dyspnea is the most common symptom<br />Symptoms of left ventricular failure are absent<br />Hoaseness of voice may be present.<br />Cyanosis may be overlooked.<br />There is marked leg fatigue and absence of dyspnea<br />Rarely patients may have swelling and pain in lower limbs.<br />
  25. 25. Physical apperance<br />Physical underdevelopment due to a large shunt<br />Maternal rubella syndrome: cataract, deafness and mental retardation<br />Rocker bottom feet and loose skin is present in trisomy 13<br />In this syndrome assosiated VSD is usually present<br />
  26. 26. Examination <br />Differential cyanosis and clubbing is pesent in shunt reversal<br />It can be brought out by exersise or a warm water bath<br />Useful to have patient sit with hands and feet together.<br />
  27. 27.
  28. 28. Arterial pulse<br />A wide pulse pressure is present<br />Pulse has a brisk rise, single peak and rapid collapse<br />Diastolic pressure is low, systolic is high<br />The peripheral pulses are bounding<br />If the shunt is small or if there is pulmonary hypertension the bounding pulse is absent<br />
  29. 29. JVP<br />JVP is normal in small shunts<br />In patients of cardiac failure the jvp is elevated and prominent A and V waves are present<br />Prominent A waves are present in high pulmonary resistance<br />
  30. 30. Auscultation <br />The classic murmur of uncomplicated PDA rises to peak in latter systole<br />Continues without interruption through the second heart sound<br />Declines in intensity in diastole <br />a silent interval may be present towards the end of diastole<br />
  31. 31. Continious murmur<br />A small duct results in a soft , high frequency continuous murmur <br />A larger duct causes a loud noisy machinery murmur<br />Loud murmur becomes soft if there is narrowing of the duct.<br />The murmur is dependent on the pressure difference between aorta and pulmonary artery<br />
  32. 32. Progression of murmur<br />As the diastolic pressure of pulmonary artery increases the patient is left with a holosystolic murmur<br />As pulmonary hypertension progresses further the systolic component also disappears <br />Right to left flow across PDA does not have a murmur<br />With increasing PH Gibson murmur is abolished<br />Findings of pulmonary hypertension are present<br />
  33. 33. Newborn <br />In newborns the classic murmur is absent <br />Only a soft systolic murmur may be present<br /> this is due to high pulmoary pressures<br />However the signs of cardiac failure are present<br />
  34. 34. Second heart sound<br />Paradoxical spitting is present in patients of large left to right shunts<br /> due to Prolonged LV ejection and short RV ejection<br />Difficult to detect on auscultation<br />With shunt reversal the second heart sound is closely split with loud pulmonary component<br />
  35. 35. ECG <br />Small ductus ECG may be normal<br />Variation in ecg depend on the volume overload of LV and pressure overload of RV <br />Usually have sinus rhythm<br />P waves are notched, bifid and prolonged<br />s/o left atrial enlargement<br />With development of pulmonary hypertension signs of biatrial enlargement are present<br />
  36. 36. PR interval is prolonged in 10 to 20 percent of patients<br />QRS axis is normal<br />Volume overload of left ventricle results in deep s waves in v1, tall r waves I v5 to v6, deep q waves and tall t waves<br />A large shunt with pulmonary hypertension results in features of biventricular hypertrophy<br />Large equidiphasic complexes are present from v1 to v6<br />
  37. 37. ECG in right to left shunt<br />In PDA with right to left shunt peaked narrow right atrial P waves appear in 2,3,and v1<br />QRS axis shows right axis deviation<br />Right ventricular hypertrophy<br />R waves in v5, v6 remain tall bur the q waves and the tall t waves disappear <br />
  38. 38. X ray chest<br />Variation in XRAY depend on size, duration and direction and pulmonary pressures<br />The ductus may be seen as a convexity between aorta and pulmonary artery<br />In older patients calcium may be depoisted<br />
  39. 39.
  40. 40. Left to right shunt causes increase in pulmoary plethora<br />Pulmonary trunk and main branches are dilated<br />Ascending aorta is enlarged in adults<br />LA and LV are enlarged<br />RA and RV dilatation occurs when pulmonary hypertension is present<br />
  41. 41. Right to left shunt<br />RV is hypertrophied<br />Pulmonary trunk and main branches are dilated<br />Peripheral vasculature is reduced<br />Ascending aorta is normal sized<br />Patients who have shunt reversal have larger hearts<br />Both RV and LV enlargement is seen<br />
  42. 42. Echocardiography <br />A complete echocardiographic evaluation of the PDA includes <br />two-dimensional imaging of the ductus, <br />evaluation of the degree of shunting at the ductus, and <br />evaluation of pulmonary artery pressure using Doppler echocardiography<br />
  43. 43. Anatomic assessment<br /> Most commonly, the ductus is imaged in the parasternal and suprasternal notch views<br /> In the high parasternal short axis view, with the transducer oriented leftward toward the pulmonary artery bifurcation, the ductus can be imaged coursing between the pulmonary artery and the descending aorta <br />Absolute quantification of its diameter is the best way to determine its presence or absence<br />
  44. 44.
  45. 45. In the suprasternal notch window, the ductus arises from the descending aorta at the level of the left subclavian artery, and courses anteriorly to join the pulmonary artery<br />
  46. 46.
  47. 47.
  48. 48. Color flow mapping is particularly helpful in the setting of a small PDA, <br />Determination of the origin of the retrograde flow into the pulmonary artery using two-dimensional imaging as well as color flow mapping is crucial to avoid confusion of the patent ductus with other aortopulmonary shunts<br />
  49. 49.
  50. 50. The Size of the Left Atrium<br />Left atrial (LA) enlargement signifies increased pulmonary venous return because of left-to-right ductal shunting<br />
  51. 51.
  52. 52. Left Ventricular Size<br />This will enlarge as cardiac output increases with both increased pulmonary venous return and with increased diastolic run-off<br />Descending Aortic Flow in Diastole<br />The presence of a significant ductal shunt results in diastolic run-off to the pulmonary circulation<br />
  53. 53.
  54. 54. Left Pulmonary Artery Diastolic Flow Velocity<br />This is higher with large left-to-right shunts.  Values less than 15cm/sec are seen when the duct is closed<br />
  55. 55.
  56. 56.
  57. 57. Hemodynamic assessment<br />The pulmonary to systemic flow ratio (Qp:Qs) can be determined echocardiographically<br />When the pulmonary artery pressure is lower than systemic arterial pressure, there is continuous left-to-right shunting demonstrated. <br />The velocity of flow across the ductus, measured by either pulsed or continuous wave Doppler,<br />can be translated into the gradient between the aorta and the pulmonary artery<br />
  58. 58.
  59. 59. When the pulmonary artery pressure is equal to systemic pressure, pulsed Doppler within the ductus demonstrates systolic right-to-left shunting, with diastolic left-to-right flow within the vessel <br />
  60. 60. Cardiac Catheterization<br />Color Doppler flow mapping is generally as sensitive as cardiac catheterization for detecting even a small PDA<br />In children with pulmonary hypertension, determining the exact location of the shunt can be difficult<br />Right heart catheterization alone usually suffices to confirm the diagnosis<br />an additional lesion such as ventricular septal defect is suspected<br />
  61. 61. An increase of pulmonary arterial blood oxygen content of >0.5 mL/dL or a saturation increase of >4% to 5% from that in right ventricular blood indicates a significant left-to-right shunt at the pulmonary arterial level<br />An increase in oxygen saturation in pulmonary arterial blood is not diagnostic of a PDA, but may be present in lesions such as aortopulmonary window or a high ventricular septal defect<br />
  62. 62.
  63. 63. a small communication, pulmonary arterial blood pressures are normal, but systemic arterial pulse pressure may be slightly widened<br />a moderate-sized defect,<br />1. pulmonary arterial systolic, diastolic, and mean blood pressures may be slightly elevated. <br />2. Systemic arterial diastolic blood pressure falls, <br />3. whereas systemic arterial pulse pressure increases<br />
  64. 64. large shunt hemodynamics<br /> pulmonary and systemic arterial pressures are equal, <br />left atrial mean pressure may be increased substantially, <br />and a prominent V wave is seen. <br />Left ventricular end-diastolic pressure may be elevated,<br /> a diastolic pressure gradient between the left atrium and left ventricle is demonstrated.<br /> A small systolic pressure difference between the left ventricle and aorta is also encountered<br />
  65. 65. Angiography<br />it is the most effective test for defining the anatomy of the PDA<br />Contrast medium is injected into a catheter passed through the PDA into the aorta from the pulmonary artery or into the aorta retrogradely from the femoral artery<br />PDA usually is widely dilated, and the ductus narrows down at the pulmonary arterial end<br />
  66. 66. the lateral projection, or occasionally the left anterior oblique projection, demonstrates the anatomy most clearly<br />The AP camera can be positioned in the right anterior oblique caudal position to demonstrate the PDA<br />selective descending aortography is essential in patients of VSD or ASD to demonstrate PDA <br />
  67. 67.
  68. 68. Magnetic Resonance Imaging<br />simpler techniques such as two-dimensional echocardiography Doppler evaluation accurately define the anatomy<br />These studies can be of use in adolescents or adults with poor echo windows<br />Velocity-encoded cine MRI imaging for estimation of left-to-right shunting may have additional clinical utility<br />
  69. 69.
  70. 70. Percutaneous closure <br />A variety of devices have been used for percutaneous closure of a PDA<br />It is the standard of care in most patients<br />Exception in premature and small infants with large shunts<br />Have been available for last 20 years<br />
  71. 71. Coils <br />Stainless steel Gianturcocoils<br />Earlier used for AV malformations<br />For duct closure the PDA should be less than 2 mm in diameter, long to accommodate loops and should have sufficient aortic ductaldiverticulum<br />The coils are deployed in a retrograde fashion from the aorta<br />Coil embolisation is a dangerous complication<br />Modified coils with release mechanism are available <br />
  72. 72.
  73. 73.
  74. 74. Multiple coils are used for large PDA<br />PDA closure rate are around 95 to 100% at 2 years<br />Residual shunt causes haemolysis<br />Modifications available are<br />Giantruco-grifika vascular occlusion device<br />Nit occlud PDA occluder<br />
  75. 75. Duct occluder device<br />AMPLATZ duct occluder is only device which is FDA approved<br />Cone shaped device<br />Antegrade venous approach<br />Delivery cable- release notch<br />98% closure at 6 months in large PDA <br />Complications are left pulmonary artery stenosis, aortic coarctation<br />Small ducts are avoided<br />
  76. 76.
  77. 77.
  78. 78.
  79. 79. Follow up<br />Anticoagulation for 6 months<br />Endocarditisprophylaxsis<br />Follow up 2d echo after 6 months<br />
  80. 80. Thank you <br />

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