Presentation is loading. Please wait.

Presentation is loading. Please wait.

D-TGA Dr. Tahsin.N. TRANSPOSITION Abnormal origin of the Aorta and Pulmonary Artery from the ventricular complex Atrioventricular concordance with ventriculo-arterial.

Similar presentations


Presentation on theme: "D-TGA Dr. Tahsin.N. TRANSPOSITION Abnormal origin of the Aorta and Pulmonary Artery from the ventricular complex Atrioventricular concordance with ventriculo-arterial."— Presentation transcript:

1 D-TGA Dr. Tahsin.N

2 TRANSPOSITION Abnormal origin of the Aorta and Pulmonary Artery from the ventricular complex Atrioventricular concordance with ventriculo-arterial discordance Abnormal spatial relationship of the great arteries Results in two circulations in parallel

3 Incidence & Prevalence 5% to 7% of all congenital cardiac malformations The incidence is reported to range from 20.1 to 30.5/100,000 live births strong (60%–70%) male preponderance

4 Embryology

5 1. Spiral aortico-pulmonary septum forms but does not spiral or twist during its partitioning of the truncus arteriosus a. Aorta arises from right ventricle b. Pulmonary trunk arises from the left ventricle 2. Result is two closed circuits a. Systemic – unoxygenated – repeatedly re-circulated b. Pulmonary - oxygenated - repeatedly re-circulated

6 Embryology The normal conus is subpulmonary, left-sided and anterior ; it prevents fibrous continuity between the pulmonary and tricuspid valve rings. In TGA, the infundibulum is usually subaortic, right-sided and anterior; it prevents fibrous continuity between the aortic and tricuspid valve rings and further results in abnormal pulmonary to mitral valve ring fibrous continuity.

7 Anatomy The common clinical type - situs solitus of the atria, concordant AV and discordant ventriculoarterial alignments - complete TGA. TGA {S,D,D} - TGA with situs solitus (S) of the atria and viscera, usual (D) looping of the ventricles and an anterior and rightward (D) aorta.

8 Anatomy- Great artery relationship Situs solitus and intact ventricular septum - the aortic root is directly anterior or anterior and to the right of the pulmonary trunk in a slightly oblique relationship Less commonly, the aorta may be positioned anterior and to the left or, rarely, posterior and to the right of the pulmonary trunk.

9 Coronary Anatomy The two aortic sinuses of Valsalva adjacent to the aorticopulmonary septum that “face” the pulmonary artery contain the ostia of the coronary arteries in more than 99% of cases

10 Coronary anatomy Usual-66.9 CX from RCA-16.1 Single RCA-3.9 Single LCA-1.7 Inverted-2.4 Intramural LCA-2.1 Other-1.6

11 SA node artery Origin and proximal course of artery may be variable; reaches the sinus node by the interatrial groove on the anterior surface of the heart, occasionally with an intramyocardial course in the anterosuperior rim of the fossa ovalis. It can be damaged easily during balloon atrial septostomy, during surgical septectomy or when this portion of the septum is widely excised as in the Mustard or Senning atrial switch operation.

12 Anatomy - Coexisting Anomalies Nearly half of the hearts have no other anomaly except a PFO or a PDA. The VSD is the most frequent coexisting anomaly-40% to 45%. - perimembranous (conoventricular 33%) - AV canal (inlet septum 5%) - muscular (27%) - malalignment (30%) - conal septal hypoplasia type (5%)

13 VSD The subaortic stenosis caused by the anterior malalignment of the infundibular septum is frequently associated with aortic arch hypoplasia, coarctation or even complete interruption of the aortic arch Posterior (leftward) malalignment is associated with varying degrees of LVOTO–subpulmonary stenosis, annular hypoplasia or even pulmonary valvar atresia

14 Subpulmonary Stenosis 25% [5%] Fixed -Circumferrential fibrous membrane /diaphragm - Fibromuscular ridge - Herniating tricuspid leaflet tissue - Anomalous MV septal attachments - Tissue tags from membranous septum Dynamic-associated with SAM

15 Subaortic Obstruction Rightward and anterior displacement of the infundibular septum Associated aortic arch anomalies - hypoplasia - coarctation - interruption Asso. RV hypoplasia & tricuspid valve anomalies

16 TV anomalies Nearly 31% Functionally imp 4% Ratio of tricuspid to mitral anulus circumference is less than 1 in almost 50% of cases, whereas in normal hearts this ratio is always greater than 1

17 TV anomalies Straddling/overriding of chordae Overriding of the tricuspid annulus Abnormal chordal atatchments Dysplasia Accessory tissue Double orifice

18 MV anomalies Nearly 20% Functionally imp 4% – Cleft anterior mitral valve leaflet – anomalous papillary muscles and chordae – Straddling – redundant tissue tags

19 Juxtaposition of atrial appendages Both appendages or left + part of right are adjacent 2-6% Left > right -6x Female preponderance often additionally associated with major cardiac pathology, including dextrocardia, VSD, bilateral infundibulum, right ventricular hypoplasia and tricuspid stenosis or atresia. Imp in BAS

20 Bronchopulmonary Collateral Circulation Bronchopulmonary anastomotic channels > 30% of infants with TGA under 2 years of age Persistence of a significant bronchopulmonary collateral circulation after surgical repair - large enough left-to-right shunt – CCF - warrant catheter embolization

21 PBF 50% of the patients - greater proportion of blood flow to the right lung than normal due to rightward alignment of MPA associated with some degree of hypoplasia of the left pulmonary arterial vessels and is further manifested in the occasional reports of unilateral, always left-sided, pulmonary vein stenosis or hypoplasia.

22 PBF

23 Postnatal Physiology of TGA

24 Determinants of effective gas exchange Effective ventilation Effective Pulmonary circulation – Pulmonary blood flow – Pulmonary vascular resistance Existence of a communication between pulmonary and systemic circuits – Persistent fetal channel – PFO or DA – Abnormal channels – ASD, VSD Effective delivery of oxygenated blood to the tissues

25 Definition of shunts Anatomical shunts – Left to Right: Blood flowing from left sided chambers to the right sided chambers – Right to Left: Blood flowing from right sided chambers to the left sided chambers

26 Definition of shunts Physiological shunts – Left to right: The volume of oxygenated pulmonary venous return recirculated to pulmonary circulation (Qp – Qep) – Right to left shunt: The volume of systemic venous return that contributes to cardiac output (reentering the systemic circulation) without having passed through the pulmonary circulation (Qs – Qep)

27 Definition of shunts Effective pulmonary blood flow (Qep): – The volume of systemic venous return that is effectively oxygenated in the lungs Effective systemic blood flow (Qes): – The volume of oxygenated pulmonary venous return that enters the systemic circulation and perfuses the systemic capillary bed

28 = Effective Systemic Blood Flow TGA: Atrial and Ventricular level shunts From LA to RA / LV to RV – Anatomically left to right – Physiologically, this volume of oxygenated blood enters systemic circulation. Hence, they contribute to Qes

29 TGA: Atrial and Ventricular level shunts From RA to LA/ RV to LV – Anatomically, right to left shunt – Physiologically, this volume of systemic venous blood enters pulmonary circulation. Hence they contribute to Qep = Effective PBF

30 Recirculating Oxy Blood Recirculating systemic blood

31 TGA: Shunt at PDA level Aorta to PA flow: – Anatomically it is left to right – Here the deoxygenated systemic venous blood enters pulmonary circulation. Hence, this volume contributes to Qep PA to Aorta flow: – Anatomically it is right to left – Here the oxygenated blood enters systemic circulation. Hence, this volume contributes to Qes Thus, the flow across the ductus is functionally opposite to that of flow across ASD or VSD in TGA

32 Systemic venous return Pulmonary venous return Anat R-L Anat L-R Physio R-L Physio L-R BODY LUNGS RIGHT HEART LEFT HEART

33 Unique feature Net inter-circulatory mixing volume is constant: net R-L, L-R, Qep and Qes are equal to each other Any major difference in the volumes would result in depletion of blood volume of one circulation at the expense of overloading the other circulation

34 Precise factors controlling intercirculatory exchange SPECULATIVE, MULTIPLE – LOCAL PRESSURE GRADIENTS Compliance of the cardiac chambers Phase of respiratory cycle Vascular resistances Heart rate Volume of blood flow

35 Flow across the communications “Rules of the Heart” With only ASD, the flow has to be bidirectional If the flow is only or predominantly left to right across the ASD, it suggests presence of additional shunt (VSD or PDA) Unrestrictive VSD - flow is bidirectional Except in the initial few days, PDA flow is always left to right (Ao to PA). Presence of right to left flow across ductus may suggest the presence of coarctation of aorta

36 Right to Left Shunt Systole Left to Right Shunt Diastole

37 Initially, bidirectional flow across the ductus Later, once the PVR falls, the flow essentially becomes aorta to PA The pulmonary circulation becomes overloaded fast, especially if the PFO is restrictive

38 Factors influencing systemic saturation Extent of inter-circulatory mixing and Total pulmonary blood flow High PBF results in increased oxygenated blood available in the left sided chambers for mixing: higher systemic SO2 if there is good mixing Reduced PBF will result in low systemic SO2 in spite of adequate anatomic shunts

39 Factors influencing systemic saturation If there is delay in the fall of PVR (PPHN), hypoxemia will persist despite adequate ASD Need ECMO or urgent ASO Hypoxemia provokes a fall in SVR and increase the recirculating systemic volume Fall in SVR may deplete the pulmonary circulation further

40 Role of bronchopulmonary collaterals Systemic arterial hypoxemia may stimulate development of bronchpulmonary collaterals Usually in TGA with solely a restrictive inter-atrial communication Prolonged survival of such infants may be due to this extra- cardiac site of shunting/mixing

41 History M:F – 4:1;unless juxtaposition of atrial appendages Usually in multigravida-2X increase in > 3 pregnancies Familial recurrence-monogenic inheritance

42 Cyanosis As early as day 1 in pts with IVS(1 st hr-56%;1 st day-90%) More intense if associated PS/atresia Mild if associated non restrictive VSD PS often responsible for hypercyanotic spells-intense cyanosis, tachypnea, extreme irritability and hypothermia Squatting is rare Reverse differrential cyanosis

43 CHF In patients with a large PDA Large VSD

44 Mortality 1 st week-30% 1 st month-50% 1 st year-90% Depends on the degree of shunting Moderate PS improves survival Predilection for brain abscess but rare < 2 years

45 Appearance Birth weight greater than normal Reverse differential cyanosis Varicosities of scalp and arms

46 Arterial Pulse Bounding pulse - due to large volume of highly unsaturated blood - Not due to PDA-since only systolic shunt from aorta to PA Diminished femoral pulses - CoA - Subaortic stenosis-anterior and rightward displacement of septum

47 Palpation Nomal in neonates RV impulse in patients with CHF LV impulse – non restrictive VSD with low PVR Palpable S2  A2

48 Auscultation Loud A2 LV S3-mildly cyanosed patients,increased PBF,LV failure RV S3-deeply cyanosed patients, increased systemic flow, RV failure

49 Auscultation Ejection click-pulmonary;does not decrease with inspiration Aortic-subaortic stenosis  dilated aortic root MSM-aortic:hypervolemic and hyperkinetic circulation Pulmonary: valvular- after few weeks of birth, progressively increases Subvalvar dynamic obstruction-3 rd LICS and radiates to the right

50 Auscultation VSD: absent  holosystolic  shortens  abolished PDA: Systolic if large PDA since high PVR curtails diastolic flow Continuous if restrictive PDA Continuous murmurs may arise in large systemic arterial collaterals but rare MDM may be heard across AV valves

51 ECG Normal in first few days of life RAE-increased pressure(CHF)/volume (hypervolemic systemic circulation) LAE-large ASD,increased PBF RAD-occurs when LV volume overload is curtailed by pulmonary vascular disease or PS

52 ECG RVH - NR VSD +high PVR/PS BVH - NR VSD + low PVR Right precordial T waves not inverted but rather distinctly taller than the left sided T waves

53

54 CXR Absent thymic shadow after 12 hours of life Narrow vascular pedicle bcoz - AP orientation of great vessels Right aoric arch % Egg on side appearance Juxtaposition-localised bulge along the mid left cardiac border which represents contiguous mass of the 2 appendages together PBF & Heart size inversely proportional

55

56 ECHO

57 Diagnosis Detection & quantitation of shunt Detection of outfow obstructions Asso anomalies Coronary Anatomy Post op Detection of Complications

58

59 Cardiac catheterization in TGA

60 Fallacies in application of Fick’s Principle in calculating shunts and flows in TGA Oxygen consumption is not normal, so assumed values are unreliable Arteriovenous oxygen differences may be very small, so magnitudes of errors in calculated values would be very large. Effect / contribution of Bronchopulmonary collaterals to PBF – can result in overestimation.

61 TGA and PVOD

62 Changes in Pulmonary Vascular Resistance Accelerated PVD is common With unrestrictive VSD, Grade 3 or 4 changes seen in 20% before 2 months and in 80% by 1 year Without VSD or PDA, it is seen in 6%, progression is slower than with VSD The number of intra acinar pulmonary arteries are also shown to be decreased

63 In TGA/ASD, regression of PVR occurs as in simple ASD but subsequently PVOD may develop rapidly. Reduced saturation Increased hematocrit Increased shear stress PVOD Bronchial artery collaterals bring poorly saturated blood to pulmonary vessels Short MPA

64 Metabolism in TGA physiology Oxygen demands are high while delivery and uptake is poor – at baseline Metabolic acidemia, lactic acidosis HYPOTHERMIA can KILL – EXAGGERATING TISSUE HYPOXIA AND METABOLIC ACIDEMIA Hypoglycemia Hyperinsulinemia

65 Management

66 Definitive Repair at three levels: the atrial level : Senning or Mustard Sx ventricular level : Rastelli operation great artery level : arterial switch operation or Jatene operation Damus-Kaye-Stansel operation in conjunction with the Rastelli operation can be used in patients with VSD and subaortic stenosis Lecompte Operation-VSD+subpulmonary stenosis

67 Arterial switch operation (Jatene operation) Advantages physiologic correction fewer long-term complications – Arrhythmias – RV dysfunction – baffle stenosis – tricuspid regurgitation (TR).

68 Arterial switch operation (or Jatene operation)

69 Pre requisite An LV that can support the systemic circulation after surgery The LV pressure should be near systemic levels at the time of surgery, or the switch should be performed shortly after birth (i.e., before 2 weeks of age). In patients whose LV pressure is low, it can be raised by PA banding, either with or without a shunt, for 7 to 10 days (in cases of a rapid, two-stage switch operation) or for 5 to 9 months before undertaking the switch operation. LV pressure >85% and LV posterior wall thickness >4.5 mm appear to be satisfactory.

70 Pre-op Coronary artery pattern amenable to transfer to the neoaorta without distortion or kinking. Risk is high when the left main or LAD coronary artery passes anteriorly between the aorta and the PA.

71 Pre-op The left ventricular inflow and outflow tracts must be free of significant structural abnormality. The right ventricular outflow tract should be free of significant stenosis.

72 Anatomic variants that may impact operative mortality include – An intramural course of a coronary artery – A retropulmonary course of the left coronary artery – Multiple VSDs – Coexisting abnormalities of the aortic – Straddling AV valves – Longer duration of global myocardial ischemic (cross-clamp) – prolonged circulatory arrest times

73 Complications PA stenosis at the site of reconstruction - 5% to 10% complete heart block - 5% to 10%. Aortic regurgitation (AR) – late complication > 20% of patients especially PA banding – An important cause of AR may be unequal size of the pulmonary cusps that leads to eccentric coaptation Coronary artery obstruction – myocardial ischemia, infarction, and even death.

74 Atrial level Surgery Mustard operation: This oldest surgical technique redirects the pulmonary and systemic venous return at the atrial level by using either a pericardial or a prosthetic baffle.

75 Senning operation: This is a modification of the Mustard operation. It uses the atrial septal flap and the RA free wall to redirect the pulmonary and systemic venous return

76

77 Complications a.Obstruction to the pulmonary venous return (<5% of all cases) b.Obstruction to the systemic venous return (<5% of all cases) c.Residual intra-atrial baffle shunt (=20% of all cases) d.Tricuspid valve regurgitation (rare) e.Absence of sinus rhythm (>50% of all cases) and frequent supraventricular arrhythmias f.Depressed RV (i.e., systemic ventricular) function during exercise g.Sudden death attributable to arrhythmias (3% of survivors) h.Pulmonary vascular obstructive disease

78 Rastelli operation In patients with VSD and severe PS The LV is directed to the aorta by creating an intraventricular tunnel between the VSD and the aortic valve. A conduit is placed between the RV and the PA

79 Rastelli operation

80 Complications conduit obstruction (especially in those containing porcine heterograft valves) complete heart block (rarely occurs). This conduit needs to be replaced as the child grows.

81 Medical Prostaglandin E1 infusion should be started to improve arterial oxygen saturation by reopening the ductus. This should be continued throughout the cardiac catheterization and until the time of surgery. Oxygen should be administered for severe hypoxia. Oxygen may help lower pulmonary vascular resistance and increase PBF, resulting in increased systemic arterial oxygen saturation.

82 Role of PGE1 in TGA Considerable benefit in first few days till PVR is elevated, especially if PFO is small Enables bidirectional shunting, improves mixing If valve of FO is competent, it would result in increased LA pressure and pulmonary edema

83 Atrial Septostomy Before surgery, cardiac catheterization and a balloon atrial septostomy (i.e., the Rashkind procedure) are often carried out to have some flexibility in planning surgery. a balloon-tipped catheter is advanced into the left atrium (LA) through the PFO. The balloon is inflated with diluted radiopaque dye and abruptly with-drawn to the right atrium (RA) under fluoroscopic or echo monitoring.

84

85 Atrial Septostomy For older infants and those for whom the initial balloon atrial septostomy was only temporarily successful, blade atrial septostomy may be performed. Following this, the balloon procedure can be repeated for a better result.

86 Pulmonary Artery Banding Transposition associated with large VSD without LVOTO To prevent Heart failure Pulmonary vascular disease Present Indications Presence of complex/multiple VSDs Coexisting medical conditions that cause a delay in surgery To train LV before switch in TGA/IVS

87 Systemic-Pulmonary Anastomosis TGA/VSD and severe LVOTO Operative mortality - as low as 5%. Reassessment of pulmonary vascular resistance

88

89 D-TGA (Complete Transposition of great arteries) Severe cyanosis in a large newborn Male preponderance (3:1) Single S2 Signs of CHF (±) Usually no heart murmur “Egg-shaped” heart with narrow waist (on x-ray film) ECG: Normal or RVH

90 THANK U


Download ppt "D-TGA Dr. Tahsin.N. TRANSPOSITION Abnormal origin of the Aorta and Pulmonary Artery from the ventricular complex Atrioventricular concordance with ventriculo-arterial."

Similar presentations


Ads by Google