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Tga rakesh edited ppt
This document discusses the anatomy, pathophysiology, and clinical presentation of transposition of the great arteries (TGA). Key points include: - In TGA, the aorta arises from the right ventricle and the pulmonary artery arises from the left ventricle, compared to the normal arrangement. This results in deoxygenated and oxygenated blood mixing through a ventricular septal defect or patent ductus arteriosus. - Survival without treatment is poor, particularly for those with an intact ventricular septum. Common associated anomalies include ventricular septal defects. Long term complications include pulmonary vascular disease and left ventricular outflow tract obstruction. - The document provides detailed descriptions of the anatomical variations and abnormalities
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- 1. DR RAKESH KUMAR MCHCTVS,AIIMS,NEW DELHI
- 2. • TGA liketetralogy and DORV is an anomaly of conotruncal development. • Two basic theories that attempt to explain the development of conotruncal anomalies.
- 3. • Conotruncus whichwill ultimately form the aorta and pulmonary artery formed as a single tube. • A process of spiral septation divides the conotruncus into the two great vessels which should wrap around each other. • If the septum does not ‘spiral’ in the usual fashion at all, the great vessels will be parallel to each other and there will be transposition of the great arteries.
- 4. Usually theaortic, tricuspid and mitral valves are in fibrous continuity, united by the fibrous skeleton of the heart. Only the pulmonary valve is separate, being lifted superiorly from the other three valves by the subpulmonary conus (infundibulum)
- 5. • Van Praaghsuggested that there is no subpulmonary conus and the aorta comes to lie anterior to the pulmonary artery. • There is a fibrous continuity between the pulmonary and mitral valves rather than the usual continuity between the aortic and mitral valves. • Only the aortic valve is separate from the other three valves.
- 6. NORMAL HEART TGAHEART
- 7. • RIGHT VENTRICLE •LEFT VENTRICLE • VENTRICULAR WALL THICKNESS, CAVITY SHAPE & FUNCTION • ATRIA • CONDUCTION SYSTEM • GREAT ARTERIES • CORONARY ARTERIES • PULMONARY VASCULAR DISEASE • CO-EXISTING CARDIAC ANOMALIES
- 8. Normally positioned,hypertrophied, and large in TGA. In about 90% of cases: ◦ Subaortic conus is seen, ◦ Aorta is rightward and anterior and ascends parallel to the posterior and leftward pulmonary trunk.
- 10. INFUNDIBULAR SEPTUM JOINING NORMALLY WITH THE VENTRICULAR SEPTUM BETWEENTHE LIMBS OF THE TSM HYPERTROPHIED RV
- 11. Less wedgingof the pulmonary trunk between the mitral and tricuspid valves in TGA than of the aorta in normal hearts. Larger area of contiguity exists between the mitral and tricuspid valves than normally.
- 12. These atrioventricular(AV) valves may be at virtually the same level, and the AV septum and membranous interventricular septum are then smaller than usual or (rarely) absent. The right fibrous trigone is abnormally shaped and attenuated.
- 13. • Infrequently contains a conus typically pulmonary mitralfibrous continuity exists, comparable with aortic mitral continuity in the normal heart. MITRAL VALVE PULMONARY VALVE
- 14. In about8% of hearts with TGA, and most often in those with a VSD, a subpulmonary conus is present in the LV. The subpulmonary conus is frequently stenotic.
- 15. RV wallis considerably thicker than normal at birth and increases in thickness with age. LV wall is of normal thickness at birth. Wall thickness remains static, however, leading to less-than-normal thickness within a few weeks of birth and a relatively thin wall by age 2 to 4 months.
- 17. LV cavityis the usual ellipsoid in shape at birth but soon becomes banana shaped. RV function is usually normal in TGA in the perinatal period.
- 18. Thereafter, whenthe ventricular septum is intact, RV end-diastolic volume is increased and RV ejection fraction decreased. Depressed RV function results from relative myocardial hypoxia or the geometry of the chamber & unlikely by increased afterload or decreased preload.
- 19. Are normallyformed in TGA. Right atrial size is usually larger than normal, particularly when the ventricular septum is intact.
- 20. • AV nodeand bundle of His lie in a normal position. • The left bundle branch originates more distally from the bundle of His than usual and arises as a single cord rather than a sheath.
- 21. Damage tothe bifurcation of the bundle at VSD closure is more likely to produce complete heart block than in the normally structured heart.
- 22. • The aortais most often directed anterior or slightly to the right. • In 13% to 30% of patients with TGA, aortic and pulmonary commissures are not precisely aligned because of malalignment of either the aortic or mitral valve. • Recognition of commissural malalignment is important in planning the coronary transfer as well as preventing neoaortic valve regurgitation.
- 23. Usually arisefrom the aortic sinuses that face the pulmonary trunk, regardless of the inter- relationships of the great arteries. Thus, the noncoronary sinus is usually the anterior one.
- 24. • A moreuniversally applicable scheme is the Leiden convention – proposed by the anatomists Gittenberger-DeGroot and Sauer who were working in Leiden, Holland.
- 25. • According toLeiden convention Using the perspective of an individual looking from the aorta to the pulmonary artery: sinus 1 – adjacent to the pulmonary artery on the right-handside of the observer sinus 2 – adjacent to the pulmonary artery on the left handside of the observer sinus 1 Usually gives rise to the anterior descending and circumflex coronary arteries. sinus 2 usually gives rise to the right coronary artery. This can be abbreviated as (1AD,CX; 2R)
- 27. Originally described byYacoub and Radley-Smith in 1978.
- 29. Usually thearteries all arise from a single ostium in the center of the sinus. Alternatively, they may arise from a double barreled ostium consisting of two ostia immediately adjacent to each other and constituting essentially a single ostium.
- 31. Now thatrepair of simple TGA is usually performed in the first few weeks of life, and repair of TGA with VSD is usually performed in the first few months of life, pulmonary vascular disease has almost disappeared.
- 32. About 75%of neonates presenting with TGA have no important coexisting cardiac anomaly other than a patent foramen ovale or an atrial septal defect. About 25% to 40% have a large or small VSD. Only about 5% have associated LVOTO.
- 33. Same typesof VSD occur with TGA as occur in hearts with a primary VSD. Conoventricular defects of the several different varieties are most common.
- 34. In somehearts with conoventricular VSDs, the infundibular septum is malaligned and fails to insert within the Y of the TSM. The septum may be displaced leftward, resulting in a variable degree of LVOTO and or rightward, tending to result in RV (subaortic) obstruction.
- 35. • Development ofLVOTO, which produces subpulmonary obstruction, is part of the natural history of many patients with TGA. • The obstruction may be dynamic or anatomic. • LVOTO occurs in an important way at birth or within a few days in only 0.7% of patients with TGA and intact ventricular septum.
- 36. Obstruction ispresent in about 20% of patients born with TGA and VSD. LVOTO may become apparent or develop after birth in other patients, thus reaching an overall prevalence of 30% to 35%.
- 38. RV SIDE LVSIDE MALALIGNED INFUNDIBULUM DEVIATED TOWARDS LV TSM RV VSD PV MALALIGNED INFUNDIBULAR SEPTUM MERGING WITH LV WALL VSD AORTIC VALVE
- 39. PRV>PLV LEFT WARD BULGING OFIVS DYNAMIC OBSTRUCTI ON
- 40. Particularly likelyto occur if the aorta lies anterior and more to the left than usual, with increased wedging of the subpulmonary area.
- 41. • Important structuralanomalies of the mitral valve are present in 20% to 30% of hearts with TGA, mostly in combination with a VSD, • But the majority are not functionally important. • The most important from a surgical standpoint are those of mitral valve overriding or straddling, in which the mitral valve leaflet is frequently cleft.
- 42. Coexisting aorticobstruction can be discrete (coarctation or less often, interrupted aortic arch) or caused by distal arch hypoplasia. Rarely, it occurs when the ventricular septum is essentially intact, but it occurs in 7% to 10% of patients with TGA and VSD.
- 43. In thenormal heart the systemic and pulmonary circulations are in series, in transposition they function as two separate and parallel circuits. After birth, the oxygenated pulmonary venous blood does not reach the systemic circuit, and the systemic venous return does not circulate to the lungs.
- 46. This resultsin severe systemic arterial desaturation. Absence of any communication between the pulmonary and systemic circulations is incompatible with life.
- 49. • Depends upon: –pulmonary vascular resistance, – Inter-atrial communication. • When inter-atrial communication is non-restrictive &
- 50. • The presenceof a ventricular septal defect can have a variable influence on the circulation. • This in part depends on the: – size of the defect, – the presence of interatrial mixing, and – the pulmonary vascular resistance • A large interventricular communication may lead to unrestricted flow to the lungs may result in symptomatic heart failure.
- 51. PREVALENCE: Commonform of congenital heart disease, occurring in 1 : 2100 to 1 : 4500 births Accounts for 7-8% of all congenital heart disease.
- 52. 2 : 1Malepredominance increases to 3.3 : 1 when the ventricular septum is essentially intact
- 53. • When patientswith all varieties of TGA are considered: – 55% survive 1 month, – 15% survive 6 months, and – only 10% survive 1 year • Survival without treatment is different among subsets.
- 54. • It isparticularly poor in untreated patients with TGA and essentially intact ventricular septum: – 80% at 1 week – 17% at 2 months and – 4% at 1 year
- 55. • In patientswith TGA and VSD, early survival is higher: – 91% at 1 month, – 43% at 5 months, and – 32% at 1 year
- 56. The combinationof large VSD and aortic obstruction (coarctation, interrupted aortic arch) is particularly lethal: all patients die within a few months of birth with severe heart failure.
- 57. In patientswith TGA, VSD, and LVOTO, early survival is still better, reaching ◦ 70% at 1 year and ◦ 29% at 5 years, This is because in many patients LVOTO is only moderate initially.
- 58. Poor survivalin patients with TGA and essentially intact ventricular septum is related primarily to hypoxia. Intercurrent pulmonary infections may develop and are particularly lethal because they reduce Qep and lead rapidly to increasing hypoxia, acidemia, and death.
- 59. • Death inthis group may also result from cerebro- vascular events, usually caused by: – the polycythemia and – increased blood viscosity (both secondary to severe cyanosis) particularly in association with dehydration. • Nonfatal cerebrovascular events occur in about 6% of patients treated by BAS and include cerebral abscess.
- 60. Patients withTGA and VSD usually die with heart failure. Hypoxia is the primary cause of morbidity and mortality in patients with TGA, VSD and LVOTO.