CONGENITAL CYANOTIC HEART DISEASES I - ABSUTH.pptx

A guide to understanding congenital cyanotic heart diseases in paediatric patient

1. CONGENITAL CYANOTIC HEART DISEASES DR MRS ODOCHI EWURUM DEPT OF PAEDIATRICS ABIA STATE UNIVERSITY, UTURU

2. INTRODUCTION Cyanotic congenital heart defects occur with cyanosis. Cyanosis is the bluish discoloration of the skin and mucus membranes due to reduced O 2 to the tissue. It manifests when the amount of deoxygenated blood is up to 5g/dl.

3. INTRODUCTION Cyanotic congenital heart defects accounts for about 30% of all congenital cardiac defects. Without other symptoms, cyanosis makes it easier for these defects to be recognized on time.

4. INTRODUCTION Congenital heart disease produces cyanosis through the following ways: when obstruction to right ventricular outflow causes intracardiac right-to-left shunting - when complex anatomic defects, unassociated with pulmonary stenosis , cause an admixture of pulmonary and systemic venous return in the heart.

5. INTRODUCTION - by persistence of fetal pathways ( e.g right-to-left shunting across the foramen ovale and ductus arteriosus in the presence of pulmonary outflow tract obstruction) persistent pulmonary hypertension of the newborn ( PPHN) It is important to determine the cause of cyanosis early to differentiate cardiac from non-cardiac causes.

6. INTRODUCTION The hyperoxia test is one method of distinguishing cyanotic congenital heart disease from pulmonary disease with cyanosis It is carried out as follows; ( i )Determine the initial arterial blood gas (ABG) in room air (ii)Administer 100% oxygen (iii)Then repeat ABG after 10 minutes of 100% oxygen.

7. INTRODUCTION (iv)There should be only minimal change in PaO2 rarely exceeding 100mmHg after 10 minutes of oxygen if the cause is cardiac.  (v)Pulmonary disease is suspected if the partial pressure of oxygen increases to above 150 mmHg with oxygen.

8. CLASSIFICATION Cyanotic Heart Disease( CHDx ) with decreased pulmonary blood flow. These lesions must include both ; An obstruction to pulmonary blood flow (at the tricuspid valve or pulmonary valve level) A pathway by which systemic venous blood can shunt from right to left and enter the systemic circulation (via a patent foramen ovale , atrial septal defect, or VSD).

9. CLASSIFICATION Examples of CHDx with ↓ pulmonary blood flow include; - tetralogy of Fallot -pulmonary atresia with an intact septum, -tricuspid atresia

10. CLASSIFICATION (b) Cyanotic Heart Disease with increased pulmonary blood flow; -This group of lesions is not associated with obstruction to pulmonary blood flow. -Cyanosis is caused by either abnormal ventricular-arterial connections or total mixing of systemic venous and pulmonary venous blood within the heart.

11. CLASSIFICATION Examples of CHDx with ↑ pulmonary blood flow include; - transposition of the great vessels -single ventricle - truncus arteriosus -total anomalous pulmonary venous return without obstruction

12. TETRALOGY OF FALLOT INTRODUCTION Tetralogy of Fallot (TOF) is the commonest cyanotic congenital heart defect beyond the neonatal period. Accounts for 8-10% of all cardiac defects. Occurs equally in both males and females.

13. TETRALOGY OF FALLOT INTRODUCTION TOF has four components, two anatomic and two physiologic and they include; Anatomic; -Ventricular septal defect (non-restrictive) -Pulmonary stenosis ( Obstruction to right ventricular outflow) (b) Physiologic; -Overriding of the aorta -Right ventricular hypertrophy

14. TETRALOGY OF FALLOT COMPONENTS OF TOF VSD Sub-pulmonary stenosis Overriding aorta Right ventricular hypertrophy

15. TETRALOGY OF FALLOT

16. PATHOPHYSIOLOGY OF TOF Systemic venous return to the right atrium and right ventricle is normal. When the right ventricle contracts in the presence of marked pulmonary stenosis , blood is shunted across the VSD into the aorta. Persistent arterial desaturation and cyanosis result.

17. PATHOPHYSIOLOGY OF TOF Pulmonary blood flow, when severely restricted by the obstruction to right ventricular outflow, may be supplemented by the bronchial collateral circulation such as the major aortopulmonary collateral arteries (MAPCAs) arising from the ascending and descending aorta, and in the newborn, by a PDA. The degree of right ventricular outflow obstruction determines the timing of the onset of symptoms, the severity of cyanosis, and the degree of right ventricular hypertrophy.

18. PATHOPHYSIOLOGY OF TOF When obstruction to right ventricular outflow is mild to moderate and a balanced shunt is present across the VSD, the patient may not be visibly cyanotic ( acyanotic or “pink” tetralogy of Fallot ). When obstruction is severe, cyanosis will be present from birth and worsen when the ductus begins to close.

19. PATHOPHYSIOLOGY OF TOF Most children with unrepaired TOF instinctively assume the squatting position to increase the Systemic venous return and treat the TET spell. The muscle contractions caused by squatting literally squeeze venous blood to the heart, thus increasing preload.  Moreover, the muscle contractions also compress arterioles and thus increase systemic vascular resistance ( afterload ).

20. PATHOPHYSIOLOGY OF TOF The net effect of squatting is that there is an increase  in  pulmonary blood flow  and this is made possible by the relative reduction of right to left shunt as the aortic and systemic  resistance is raised  by this  posture.

21. PATHOPHYSIOLOGY OF TOF SQUATTING

22. PATHOPHYSIOLOGY OF TOF

23. CLINICAL MANIFESTATION Cyanosis not often present at birth but occurs later in the first year of life. Prominent in the mucous membranes of the lips and mouth and in the fingernails and toenails. dusky blue skin, gray sclerae with engorged blood vessels. marked clubbing of the fingers and toes. Polycythemia

24. CLINICAL MANIFESTATION CYANOSIS

25. CLINICAL MANIFESTATION Dyspnea on exertion Characteristically, children assume a squatting position for the relief of dyspnea . Paroxysmal hypercyanotic attacks (hypoxic, “blue,” or “ tet ” spells) are a particular problem during the 1st 2 yr of life. The spells occur most frequently in the morning on initially awakening or after episodes of vigorous crying.

26. CLINICAL MANIFESTATION “TET Spells” or hypercyanotic spells are acute episodes of arterial oxygen desaturation secondary to intermittent worsening of right ventricular outflow tract obstruction causing right to left shunting across the VSD. The infant may become extremely irritable, cyanotic and may lose consciousness The cause is spasm of the infundibular muscle in the RVOT, usually provoked by pain or anxiety.

27. CLINICAL MANIFESTATION Severe spells may progress to unconsciousness and, occasionally, to convulsions or hemiparesis . It can also lead to severe systemic hypoxia and metabolic acidosis. Heart failure and its symptoms are rare in TOF. This is because the volume of work of the heart is less than normal since the right ventricular pressure cannot exceed that of the left due to the non-restrictive VSD.

28. CLINICAL MANIFESTATION left anterior hemithorax may bulge anteriorly because of right ventricular hypertrophy. a systolic thrill is felt along the LLSB Murmurs (ejection systolic at LUSB or pan systolic at LLSB) Either the 2nd heart sound is single, or the pulmonic component is soft.

29. CLINICAL MANIFESTATION Growth and development may be delayed in patients with severe untreated tetralogy of Fallot , particularly when oxygen saturation is chronically <70%. Puberty may also be delayed in patients who do not undergo surgery.

30. INVESTIGATION FBC- Polycythemia , low or normal platelets Low Iron on blood film. SEUCR- low bicarbonate. Arterial blood gases- show  paO 2 both in room air and after breathing 100% O 2 . There is ↓PH and↑PCO2

31. INVESTIGATION CHEST X-RAY Normal heart size with right ventricular contour Has an upturned apex and appears to be “sitting on the diaphragm” (boot or wooden shoe (“ coeur en sabot”) shaped cardiac silhouette) Pulmonary vascular marking may be normal or decreased depending on the degree of obstruction. Right aortic arch in 25% of patients.

32. INVESTIGATION CHEST X-RAY

33. INVESTIGATION ELECTROCARDIOGRAM Right axis deviation. Right ventricular hypertrophy. A dominant R wave in the right precordial chest leads (Rs, R, qR , qRs ) or an RSR′ pattern. In some cases a positive T wave in leads V 3 R and V 1 . The P wave is tall and peaked or sometimes bifid

34. INVESTIGATION 2D-ECHOCARDIOGRAPHY This provides information on; ( i ) The extent of aortic override of the septum, (ii)The location and degree of the right ventricular outflow tract obstruction (iii)The size of the proximal branch pulmonary arteries, and the side of the aortic arch.

35. INVESTIGATION CARDIAC CATHETERIZATION; demonstrates; a systolic pressure in the right ventricle equal to systemic pressure. Pulmonary arterial pressure is usually lower than normal, in the range of 5–10 mm Hg. VENTRICULOGRAPHY - RIGHT- Selective right ventriculography best demonstrates the anatomy of the tetralogy of Fallot .

36. INVESTIGATION -LEFT: Left ventriculography demonstrates the size of the left ventricle, the position of the VSD, and the overriding aorta; it also confirms mitral-aortic continuity, thereby ruling out a double-outlet right ventricle.

37. TREATMENT Treatment of the tetralogy of Fallot depends on the severity of the right ventricular outflow tract obstruction. Infants with severe tetralogy require medical treatment and surgical intervention in the neonatal period. Therapy is aimed at providing an immediate increase in pulmonary blood flow to prevent the sequelae of severe hypoxia.

38. TREATMENT OF TOF MEDICAL TREATMENT The intravenous administration of prostaglandin E 1 (0.01–0.20 μg /kg/min), a potent and specific relaxant of ductal smooth muscle, causes dilatation of the ductus arteriosus and usually provides adequate pulmonary blood flow until a surgical procedure can be performed.

39. TREATMENT OF TOF Prevention or prompt treatment of dehydration is important to avoid hemoconcentration and possible thrombotic episodes. I ron therapy may decrease the frequency of Paroxysmal dyspneic attacks in infancy or early childhood and also improve exercise tolerance and general well-being.

40. TREATMENT OF TOF Oral propranolol (0.5–1 mg/kg every 6 hr) is used more commonly to decrease the frequency and severity of hypercyanotic spells. NaHCO 3 used to treat attendant acidosis. Infective endocarditis prophylaxis when indicated. plasmapheresis for polycythemia .

41. TREATMENT OF TOF TREATMENT OF HYPERCYANOTIC SPELL (1) Placement of the infant on the abdomen in the knee-chest position while making certain that the infant's clothing is not constrictive. (2) Administration of oxygen (although increasing inspired oxygen will not reverse cyanosis caused by intracardiac shunting).

42. TREATMEN OF TOF (3) Injection of morphine subcutaneously in a dose not in excess of 0.2 mg/kg. It provides sedation and usually is sufficient to relax the infundibular spasm and break the spell. (4)For more severe spells, SVR can be augmented with phenylephrine and the infundibular muscle can be relaxed with betablocker .

43. TREATMENT OF TOF (5) Intravenous administration of sodium bicarbonate is necessary if the spell is unusually severe.

44. TREATMENT OF TOF PALLIATIVE SURGERY

45. TREATMENT OF TOF SURGICAL TREATMENT (1) Palliative: This involves a systemic-to-pulmonary artery shunt performed to augment pulmonary artery blood flow. (2) Total: Total correction could be done at any age by VSD closure with a patch and infundibulum resection. Primary repair is performed electively at between 4 and 6 months of age.

46. COMPLICATIONS OF TOF ( i ) Cerebral thromboses usually occurs in the cerebral veins or dural sinuses and occasionally in the cerebral arteries in the presence of polycythemia and dehydration. RX is supportive, ensure adequate hydration. (ii) Polycythemia (PCV > 65%). Treated with Phlebotomy and volume replacement with albumin or saline.

47. COMPLICATIONS OF TOF (iii) Brain Abscess which can present with features of fever, headache, change in behaviour , vomiting, convulsions, paralysis. It could be due to venous blood bypassing the normal filtering action of the lungs. Rx is the use of antibiotics and surgical drainage of abscess.

48. COMPLICATIONS OF TOF (iv) Bacterial endocarditis . This may occur in the right ventricular infundibulum or on the pulmonic , aortic, or, rarely, tricuspid valves. Antibiotic prophylaxis is essential before and after dental and surgical procedures associated with a high incidence of bacteremia .

49. PULMONARY ATRESIA WITH INTACT SEPTUM Pulmonary atresia is one of the rarer cardiac defects causing cyanosis in the newborn period. It accounts for about 1% of all cardiac defects. Occurs equally in both sexes.

50. PULMONARY ATRESIA WITH INTACT SEPTUM PATHOPHYSIOLOGY the pulmonary valve leaflets are completely fused to form a membrane. the right ventricular outflow tract is atretic . Because of the absence of a VSD no blood from the right ventricle enters into the left. The right ventricle is usually hypoplastic , although the degree of hypoplasia varies considerably

51. PATHOPHYSIOLOGY OF PULM ONARY ATRESIA PATHOPHYSIOLOGY Right atrial pressure increases, and blood shunts via the foramen ovale into the left atrium, where it mixes with pulmonary venous blood and enters the left ventricle. The combined left and right ventricular output is pumped solely by the left ventricle into the aorta. In a newborn with pulmonary atresia , the only source of pulmonary blood flow occurs via a PDA.

52. PATHOPHYSIOLOGY OF PULM ONARY ATRESIA

53. CLINICAL MANIFESTATION As the ductus arteriosus closes in the 1st hours/days of life, infants become markedly cyanotic. Severe respiratory distress. 2nd heart sound is single and loud. A systolic or continuous murmur can be heard secondary to ductal blood flow. Untreated, most patients die within the 1st wk of life.

54. INVESTIGATION ( i ) CHEST X-RAY decreased pulmonary vascularity The heart may be variable in size. (ii) ELECTROCARDIOGRAPHY Tall, spiked P waves indicate right atrial enlargement. QRS voltages are consistent with left ventricular dominance or hypertrophy.

55. INVESTIGATION occasionally, patients with larger, thickened right ventricular cavities may have evidence of right ventricular hypertrophy . (iii) ECHOCARDIOGRAPHY estimates right ventricular dimensions and the size of the tricuspid valve annulus, which have been shown to be of prognostic value

56. INVESTIGATION (iv)CARDIAC CATHETERIZATION Necessary for complete evaluation and reveals right atrial and right ventricular hypertension. (v) VENTRICULOGRAPHY This demonstrates the size of the right ventricular cavity, the atretic right ventricular outflow tract, the degree of tricuspid regurgitation, and the presence or absence of intramyocardial sinusoids filling the coronary vessels.

57. TREATMENT MEDICAL Infusion of prostaglandin E 1 (0.01–0.20 μg /kg/min) to keep the ductus arteriosus open before intervention, thus reducing hypoxemia and acidemia before surgery. SURGICAL Pulmonary valvotomy and an aortopulmonary shunt is carried out to preserve adequate pulmonary blood flow.

58. TREATMENT -Through interventional catheterization the imperforate pulmonary valve is first punctured either with a wire or a radiofrequency ablation catheter, followed by a balloon valvuloplasty . If the right ventricular chamber remains hypoplastic , a modified Fontan procedure allows blood to bypass the hypoplastic right ventricle by flowing to the pulmonary arteries directly from the venae cavae .

59. TRICUSPID ATRESIA INTRODUCTION -It accounts for 1-2% of all cardiac defects in infancy. - Occurs equally in both sexes.

60. TRICUSPID ATRESIA PATHOPHYSIOLOGY There is no outlet from the right atrium to the right ventricle. the entire systemic venous return enters the left side of the heart by means of the foramen ovale or an associated atrial septal defect.

61. TRICUSPID ATRESIA

62. TRICUSPID ATRESIA PATHOPHYSIOLOGY -Left ventricular blood usually flows into the right ventricle via a VSD. -Pulmonary blood flow depends on the size of the VSD and the presence and severity of pulmonic stenosis . -Pulmonary blood flow may be augmented by or be totally dependent on a PDA.

63. TRICUSPID ATRESIA PATHOPHYSIOLOGY -If the ventricular septum is intact, the right ventricle is completely hypoplastic and pulmonary atresia is present. -Although the inflow portion of the right ventricle is always missing the outflow portion is of variable size.

64. CLINICAL MANIFESTATION OF TRICUSPID ATRESIA Cyanosis is usually evident at birth. An increased left ventricular impulse may be noted. Holosystolic murmurs audible along the left sternal border. The 1 st heart sound is usually single with increased intensity, while the 2 nd heart sound may be single or normally split. The diagnosis is suspected in 85% of patients before 2 months of age.

65. CLINICAL MANIFESTATION OF TRICUSPID ATRESIA Polycythemia . Easy fatigability. Exertional dyspnea . Occasional hypoxic episodes. At risk for spontaneous closure of the VSD leading to a marked increase in cyanosis.

66. INVESTIGATION CHEST X-RAY Pulmonary Oligaemia in normally related great vessels. Pulmonary plethora if TGA is present. ELECTROCARDIOGRAPHY -Left axis deviation and left ventricular hypertrophy. -The P waves are usually biphasic.

67. INVESTIGATION ECHOCARDIOGRAPHY 2D-Echo reveals the presence of; -a fibromuscular membrane in place of a tricuspid valve. -the variably small right ventricle. -VSD. -the large left ventricle. - The large aorta.

68. INVESTIGATION CARDIAC CATHETERIZATION -Shows normal or slightly elevated right atrial pressure with a prominent a wave.

69. TREATMENT MEDICAL -Intravenous infusion of prostaglandin E 1 (0.01–0.20 μg /kg/min). Treatment of heart failure.

70. TREATMENT SURGICAL ( i )The Blalock- Taussig procedure as a palliative systemic to pulmonary artery anastomosis aimed at increasing pulmonary blood flow. (ii) Rashkind balloon atrial septostomy or surgical septectomy for restrictive atrial level communication. ( iii)Pulmonary arterial banding

71. TREATMENT ( iv)Bidirectional Glenn shunt which involves the creation of an anastomosis between the supe-rior vena cava and the pulmonary arteries. It is done at 4-8 months of age. (v)The modified Fontan operation is the preferred approach to later surgical management. It is often performed between 1.5 and 3 yr of age.

72. TREATMENT -A modification of the Fontan procedure, known as a cavopulmonary isolation procedure, involves anastomosing the inferior vena cava to the pulmonary arteries, either via a baffle that runs along the lateral wall of the right atrium or via a homograft or Gore-Tex tube running outside the heart.

73. . THANKS FOR YOUR ATTENTION

74. SUGGESTED READING Bernstein D. Cyanotic Congenital Heart Disease: Lesions Associated with increased Pulmonary Blood Flow. In: Kleigman MR, Berham ER, Jenson BH, Stanton FB, editors. Nelson’s Textbook of Paediatrics.19 th ed. Elsevier; 2011. Okoroma E.O,Bodethomas F. Congenital heart diseases. In Azubuike JC, Nkanginieme KEO. Paediatrics and Child Health in a Tropical region.3 rd ed. Owerri : African Educational services; 2007. Jaiyesimi F. Cardiovascular diseases. In: Stanfield P, Brueton M, Chan M, Parkin M, Waterston T, editors. Diseases of Children in the Subtropics and Tropics. 4 th ed. Educational Low priced books. Internet.