Cyanotic congenital heart diseases - Single Ventricle

The topic describes the Cyanotic congenital heart disease - Single ventricle physiology. It will be useful for fellows in training for preparing presentations as well as clinicians in practice.

1. Single Ventricle Dr Anish P G 20.04.15

2. Nomenclature Different terms S ingle ventricle U niventricular heart Common ventricle S ingle functional ventricle Van Pragh : “Single Ventricle” – Inaccurate Anderson et al. Defined characteristics of a ‘Ventricle’ Inlet Trabecular Outlet

3. In a normal heart Normal ventricles Inlet From AV annulus to insertions of papillary m Doesnot require a perforate AV valve annulus Trabecular Between inlet and outlet portions Includes apex Outlet Nontrabeculated region beneath the semilunar valves The inlet and outlet portions of the morphological LV are in fibrous continuity; In RV they are separated by Crista supraventricularis E ach trabecular zone receives its own inlet

4. Anderson etal …. Ventricle A chamber which has ≥50% of the inlet part Rudimentary chambers A chamber which has ≤ 50% of the inlet portion Outlet chamber Rudimentary chamber with an outlet portion Trabecular pouches Rudimentary chambers with only a trabecular zone

5. Univentricular heart of LV type Univentricular heart of RV type Anderson etal (1984) “ Univentricular AV connection” Both inlets are committed primarily to one dominant ventricle Sequential segmental approach to define dominant ventricle, position and morphology of the rudimentary ventricle, AV connection & position of semilunar valve

6. Edwards & Maleszewski 6 possible AV connections 2 biventricular – concordance & discordance Ambiguous – atrial isomerism 3 univentricular – double inlet, single inlet & common inlet

7. Pathologic Anatomy Ventricular Morphology AV connections VA connections Interventricular connnections

8. Ventricular morphology M.C type is DILV with a hypoplastic RV Rudimentary RV – antr and supr to dominant LV & most commonly connects to Aorta- VA discordance If hypoplastic RV on the right shoulder of the heart – D loop If hypoplastic RV on the left shoulder of the heart – L loop Dominant chamber is LV if: Direct continuity between on or both AV valves and the and the semilunar valves Short axis – P lane of ventricular septum A ngled rather than perpendicular to the diaphragmatic ventricular wall D isplaced superiorly

9. DIRV – rare Hypoplastic LV Along the inferior aspect of heart towards right or left Great artery from the hypoplastic chamber is very rare VA connections Almost always – RV and Double outlet Common outlet ( Truncus ) Single outlet (pulmonary atresia or aortic atresia) RV if: Separation of AV valves from the semilunar valves by a collar of myocardium ( conus , infundibulum or outflow tract)

10. Single functional ventricle of undifferentiated or indeterminate type When morphology uncertain

11. AV connections M orphology of AV valves in DILV Mirror image morphologic MV When both atria drain to dominant ventricle MV-TV h ybrid morphology W hen one valve is straddled into the hypoplastic RV Here, AV valves are labelled as Right or Left In Common inlet AV connection Dominant chamber is almost always  RV Single inlet AV cconnection Includes – Mitral atresia & Tricuspid atresia Charact . By Imperforate valve orifice with a fibrous plug Absence of AV connection & corresponding atria & ventricles are completely separated

12. Univentricular AV connection

13. Annular features Overriding: Partial commitment of an AV valve annulus to the contralateral ventricular chamber Results from malalignment of the atrial and ventricular septa Annular commitment of ≥ 50% to a ventricular chamber establishes the valve connection to that ventricular chamber If ≥ 75% of the annulus of a common AV valve empties into one ventricular chamber  Common inlet ventricle

14. Features of the cordae & PM Straddling: Cordae and PM insert into the contralateal ventricle through a VSD DILV  AV valve may straddle into hypoplastic RV The valve that straddles is almost always on the same side as the hypoplastic outlet chamber Straddling AV valves are often large and redundant and can develop regurgitation Occasionally, stenosis of an AV valve may be seen most commonly the left-sided valve. Parachute mitral valve can also occur

15. AV Commitment

16. VA Connections A ny ventriculoarterial connection can occur C oncordant connection D iscordant connections D ouble outlet from the dominant ventricular mass or from the hypoplastic rudimentary outlet chamber Single outlet from the dominant ventricular mass VA relationship is defined by the ventricle from which most (>50 % ) of an overriding semilunar valve originates

17. In uni­ventricular heart of left ventricular morphology Majority will have discordant VA connections Shiraishi and Silverman etal 86% had TGA 63% of TGA had L Loop A orta - from the rudimentary RV anterior , and leftward of the AV valves PA- from the morphologic LV For the rest of the patients in the series 23 % had TGA of D-loop variety 14% had NRGA (Holmes heart )

18. U niventricular heart of RV morphology Double outlet from the dominant ventricular mass Single outlet with pulmonary atresia. Univentricular heart of inde­terminate morphology Often is no outlet chamber There can only be a double outlet or a single outlet

19. Pulmonary outflow tract obstruction frequent with a univentricular heart. This can occur with either Concordant D iscordant ventricular-arterial connections When subpul ­ monary obstruction occurs T ypically in the ventricle of LV morphology D ue to posterior deviation of the infundibular septum Also due to A nomalous attachments of the right AV valve Herniation of valvular tissue into the pulmonary outflow tract

20. Interventricular Communications Can be VSD Bul­boventricular foramen O utlet foramen . DILV the defect will be in the muscular portion of the trabecu­lar septum in most cases may extend into the outlet septum underneath the semilu­nar valve ( subaortic VSD ) the outlet foramen often can be restrictive The defect can be restrictive or unre­strictive at birth but often will become restrictive over time

21. Common types of SV Double Inlet Lef Ventricle Double- Inlet Right Ventricle Double- Inlet Ventricle of Mixed Morphology Double- Inlet Ventricle with Indeterminate or Undiffrentiated Morphology Single-Inlet Ventricle Common-Inlet Ventricle

22. Double Inlet Left Ventricle Van Praagh classification B ased on the great artery rela­ t ionships : I -normally related great arteries (Holmes heart) II - right-anterior aorta III - left-anterior aorta IV - left-posterior aorta (inverted ). T hree clinically observed forms A-I A-II A-III In each of these clinical forms, other common associa­tions include subaortic obstruction pulmonary outflow tract obstruction conduction abnormalities

23. Subaortic obstruction usually occurs with VA discordance L ocated primarily at the VSD ( bulboventricular foramen type) A lso secondary to severe ventricular hypertrophy within the hypoplastic RV O ccurs more often in patients with associated right AV valve atresia and in patients who have had previous PA banding procedures Pulmonary artery banding Progressive ventricular hypertrophy and obstruc­tion These patients often present in infancy with asso­ciated coarctation of the aorta

24. Pulmonary outflow tract obstruction frequent in DILV May occur with either concordant or discordant VA connections . When occurs within the left ventricular chamber due to pos­terior deviation of the infundibular septum anomalous attachments of the right AV valve herniation of valvular tissue into the pulmonary outflow tract Severe pulmonary valve stenosis and annular hypoplasia can occur . The valve is often bicuspid and thickened

25. Conduction abnormalities Similar to corrected transposition of the great arteries can be present In double inlet type The connecting AV node always is located anterolaterally at the acute margin of the right AV valve orifice perforates the annulus of the right AV valve to enter the main left ventricular chamber The nonbranching bundle courses along the right-sided rim of the VSD (outlet foramen) to reach the trabecular septum.

26. The nonbranching bundle is located on the left ventricular aspect of the trabecular septum and descends down the right rim of the ventricular septum, branching below the septal crest Although the nonbranching bundle appears to be in a different location with right­ or left-sided hypoplastic RVwhen viewed from the hypoplastic right ventricle. If the hypoplastic RV is left-sided , the conduction tissue appears to run above the ventricular defect when viewed from the MVC. If the hypoplastic RV is right sided, the conduction bundle appears to run beneath the VSD when viewed from the MVC .

27. 3 Clinically observed forms DILV with Normally Related Great Arteries (A-1 Single Ventricle, "Holmes Heart ) DILV with Right-Sided Hypoplastic Subaortc Right Ventricle (A- ll Single Ventricle ) DILV with LeftSided Subaortc Hypoplastic Right Ventricle (A-111 Single Ventricle )

28. A-1 Single Ventricle R elatively rare 15% of the Van Praagh series Embryologically , the VSD providing communication between the main left ventricular chamber and the hypoplastic RV represents the primitive bulboventricular foramen. T he VSD creates signifiant subpulmonary obstruction, resulting in a somewhat balanced circulation with some hypoxia and low pulmonary artery pressure

29. A- ll Single Ventricle 25% of the cases reviewed by Van Praagh et al S hares many anatomic features with Complete TGA with severe override and straddling of the right AV valve into the morphologic LV and associated hypoplasia of the morpho­logic RV Various types of DILV represents the extreme forms of AV valve straddling AV valve morphology also may follow this pattern Left AV valve - fea­tures of MV Right AV valve - features of TV. With VA discordance The aorta also typically  right-anterior in location. Subaortic and pulmonary stenosis may occur

30. A-111 Single Ventricle 38 % of the series review by Van Praagh et al DILV with left-sided subaortic hypoplastic right ventricle - the most common type of univentricular connection F eatures similar to corrected transposition of the great arteries but that severe overriding and straddling of the left-sided tricuspid valve ultimately resulted in predominant commitment of the left AV valve to the morphologic LV T he AV valve anatomy is not sufficiently distinct to allow accurate differentiation of morphologic MV or TV S ignifcant variation in the size of the morphologic right ventricular cavity extremely hypoplastic -a tiny slit-like chamber can be 75 % or 80% of the size of a normal right ventricular chamber

31. Associated AV valve, semilunar valve, and outflow tract anomalies may occur. Subaortic obstruction Must be assessed when considering a modifid Fontan procedure. Signifiant ventricular hypertro­phy substantially increases operative risk for Fontan operation The conduction tissue abnormalities are similar to those described for LTGA ECG features Abnormal ini­tial septal depolarization with the initial horizontal plane QRS vector directed leftward and anteriorly rather than rightward. There is an absence of a precordial Q wave

32. Double- Inlet Right Ventricle

33. Double- Inlet Right Ventricle 5 % of the series reviewed by Van Praagh et al. virtual absence of the LV Recent reviews H ypoplastic rudimentary LV Recognized by angio or echo Both AV valves either have >75 % of the total AV valve orifices or complete connection to the morphologic RV The hypoplastic LV located posteri­orly and slightly to the left of the morphologic RV C onsistent with  D -ventricular loop .

34. Less common  L-ventricular loop. V ariability in the size of the hypoplastic LV Most often it is very hypoplastic . VA connections Concordant or discordant Double-outlet right ventricle is usually present Pulmonary stenosis or atresia Frequent with infundibular and pulmonary annular hypoplasia. If there is signifiant straddling of the AV valve, the LV may be large

35. The path of the conduction tissue R elated to the location of the hypoplastic LV and Normal when the hypoplastic LV is leftward and posterior V entricular inversion Similar to Congenitally corrected transposition of the great arteries

36. Double- Inlet Ventricle of Mixed Morphology

37. Double- Inlet Ventricle of Mixed Morphology R are 5 % of the series by Van Praagh et al Also called a com­mon ventricle D esignated by Van Praagh as the C type of single ventricle with absence of the ventricular septum or undivided ventricles with a rudimentary septum. A small api­cal ridge of ventricular septum may often separate the right and left ventricular zones of the heart. Relationships of the ventricular zones are usually consistent with D-ventricular looping. T he great arteries are normally related Malposition with right- or left anterior aorta may occur. Pulmonary stenosis may be present Subvalvular or Valvular

38. The conduction system Normal R egular posterior position for the AV node There may be dual AV nodes with a sling of conduction tissue con­necting the two. The nonbranching bundle appears to descend into the remnant of ventricular septum that separates the right and left ventricular zones

39. Double- Inlet Ventricle with Indeterminate or Undifferentiated Morphology

40. Double- Inlet Ventricle with Indeterminate or Undifferentiated Morphology P rimitive form  without a rudimentary chamber. S hares many features of both DIRV and double-inlet of mixed morphology D iagnosed when no clear-cut differentiation or distinction of ventricular myocardium can be determined AV valve abnormalities Valvular stenosis or hypoplasia AV valves often are regurgitant . The great arteries Most commonly, the aorta is located anteriorly and to the right or left of the pulmonary artery Pulmonary stenosis Subbvalvular and V alvular stenosis or pulmonary atresia may be present

41. C onduction system Variable Can be normally positioned The nonbranching bundle either penetrates directly into the right lateral wall of the ventricular chamber or descends through a large trabeculation toward the ventricular apex

42. Single-Inlet Ventricle

43. Single-Inlet Ventricle I nclude all forms of univentricular AV connection resulting from atresia or absence of either the right or left AV valve. I nlet connection may be to either a morphologic right ventricle with mitral valve atresia or a morphologic LV with tricuspid valve atresia. AV concordance is common, but the AV connection can be discordant. Either ventriclec an be hypoplastic . VA concordance or discordance occurs with a range of great artery relationships from normal to transposition with a right or left anterior aorta. Subvalvular and valvular pulmonary stenosis Subaortic obstruction may occur predominantly with discordant VA connections .

44. Conduction system In AV concordance with absent right AV connection or classic tricuspid atresia  similar to that seen in isolated VSD . T he nonbranching bundle is located on the left ventricular aspect of the right rim of the VSD In AV discordance, the regular posterior node cannot make contact with the ventricular myocardium. Instead, the anterior AV node is the connecting node T he nonbranching bundle encircles the anterior aspect of the pulmonary valve to reach the right rim of the VSD In single-inlet right ventri­cle T he nonbranching bundle on the ventricular septum makes contact with the normally located posterior AV node

45. Common-Inlet Ventricle

46. Common-Inlet Ventricle Communication of both atria to a single-ventricular chamber by a common AV valve A form of AV septal defect Frequently associated with situs ambiguus , particularly asplenia Van Praagh series 33 % - Common AV inlet, with 40 % o f these having asplenia T he main ventricular chamber may be M orphologic LV (type A Van Praagh ) Morphologic RV (type B) V entricle with undifferentiated myocardium (type D) There often is double-outlet right ventricle or VA discordance with a right or left anterior aorta Stenosis or atresia of the pulmonary valve

47. MVC of left ventricular type, the right ventricular portion of the common AV valve may be stenotic or partially atretic , resulting in predominant commitment of the common AV valve to the morphologic LV. Both posterior and anterolateral node structures give rise to the penetrating bundles and a sling of conduction tissue

48. Clinical features

49. D etermined by the presence or absence of pulmonary outflow obstruction. W ithout obstruction to pulmonary blood flow Signs and symptoms typical of large, left-to-right shunting VSDs. Severe congestive heart failure with tachypnea, tachycardia , diaphoresis, hepatomegaly , and failure to thrive may manifest within thefist 3 months of life Symptoms of congestive heart failure earlier in the neonatal period will more often be secondary to associated lesions AV valve abnormalities Aortic outflw obstruction C oarctation of the aorta. Because of increased pulmonary blood flow , cyanosis may not be evident .

50. “Favorable streaming“ DILV and subaortic RV to the left (inverted) Systemic venous blood preferentially directed into the pulmonary artery and pulmonary venous return directed to the aorta “Unfavorable streaming“ Right-sided subaortic RV and various degrees of straddling right AV valve S treaming with transposition-like blood flow patterns result­ing in significant systemic hypoxemia and cyanosis

51. S oft systolic ejection murmur Flow-related relative pulmonary outflow obstruction F low - through the VSD to the hypoplastic RV Diastolic AV valve inflow murmur L arge pulmonary blood flow Pulmonary congestion and pneumonia can be the presenting findings .

52. M oderate pulmonary outflow obstruction or atresia H ypoxemia and cyanosis may be observed dur­ing the neonatal period. S ystolic thrill P ulmonary or subaortic outflow obstruction. A systolic ejection murmur and single second heart sound may be heard. The pulmonary valve closure sound may be audible and have mild degrees of pulmonary obstruction No murmur or a soft continuous murmur Patent ductus arteriosus Systemic pulmonary collateral artery with pulmonary atresia

53. Natural history W ithout PS, CHF and growth failure develop in early infancy, in association with pulmonary hypertension. Without surgery - 50% die befor reaching 1 yr of age Develop pulmonary vascular obstructive disease after the first year of life with clinical improvement of CHF Cyanosis increases if PS worsens . Progressive AV valve regurgitation is poorly tolerated Complete heart block develops in about 12% of patients SBE or cerebral complications may develop as in TOF . The cause of death CHF , arrhythmias, or sudden death

54. ECG U nusual ventricular hypertrophy pattern S imilar QRS complexes across most or all precordial leads is common (e.g., RS, rS , QR pattern ) Abnormal Q waves representing abnormalities in septal depolarization Q waves in the right precordial leads no Q waves in any precordial leads Q waves in both the right and left precordial leads AV blocks : Left Isomerism: No SAN – junctional rhythm First- or second-degree AV block may be present CHB – in L looped Single ventricles due to long course of bundle Arrhythmias occur SVT W andering pacemaker – Right Isomerism: 2 pacemakers

55. Radiographic Features DILV with hypoplastic subaortic right ventricle located anteriorly and to the left Prominent upper left-sided heart border consisting of the right ventricular infundibulum, the aortic root, and the ascending aorta ‘Waterfall right hilum’ MPA & RPA  dilated and produce a prominent upper right-sided heart border and right pulmonary hilum M oderate degree of pulmonary stenosis the pulmonary vascularity may appear normal or slightly decreased . The heart size may be normal or only mildly enlarged . P ulmonary atresia Vascularity may be reduced or asymmetric as a result of systemic-to-pulmonary artery shunting .

56. MRI For demonstration of extracardiac abnormalities of systemic and pulmonary venous connections aortic arch and central and proximal pulmonary artery branch abnormalities. C oronal images useful for segmental descriptions of congenital cardiovascular anomalies Visceroatrial situs and types of AV and VA connections. ECG-gated transverse images Useful for accurate assessment of ventricular mass E xcellent noninvasive method for preoperative assessment of ventricular mass, volume, and function for the irregularly shaped ventricular chambers

57. Echocardiographic Features The most important diagnostic sign S ingle ventricular chamber into which two AV valves open Important features to be identified from a surgical point of view 1. Morphology of the single ventricle double-inlet LV? double-inlet RV ? 2. Location of the rudimentary outflow chamber U sually left and anterior

58. 3. Size of the BVF and if there is an obstruction Obstruction is present if the Doppler gradient is more than 1.5 m/sec if the area of the foramen is less than 2 cm 2 /m 2 . A foramen that is nearly as large as the aortic annulus is considered ideal 4. Identify: Presence or absence of D-TGA or L-TGA S tenosis of the pulmonary or aortic valve S ize of the PAs

59. 5. Anatomy of the AV valves Position of the MV & TV Presence of stenosis, regurgitation, hypoplasia, or straddling 6. The size of the ASD 7. Associated defects COA Interrupted aortic arch PDA

60. Cardiac Catheterization and Angiography

61. Objectives A ssessment of hemodynamics S ystemic and pulmonary venous anatomy AV and ventricular-arterial connections V entricular morphology and function P ulmonary vascular resistance A ortic arch integrity Systemic-pulmonary collaterals

62. Venous Connections Demonstration of hepatic and inferior venacaval con­nections D emonstration of the innominate vein should establish its drainage through the right superior vena cava and exclude the presence of a persistent left superior venacava Anomalous pulmonary venous connections and pulmonary venous stenoses should be excluded If a single-inlet or an atretic AV connection is present, the presence and adequacy of an interatrial communication should be assessed

63. AV and VA Connections Cineangiography D emonstration of AV valve commitment, annulus size, and leaflt abnormalities Reliable assessment of the presence and severity of valvular regurgitation. Severe AV valvular regurgitation results in ventricular volume overload and elevated filing pressures. Preoperative recognition is mandatory for accurate assessment of the potential benefis , morbidity , and mortality of the modifid Fontan procedure compared with staged palliative procedures

64. Standard AP & Lateral projections Demonstration of the AV valves and function. D emonstration of the VA connections and great artery relationships In DILV , the AP view S ize and adequacy of the VSD Presence of s ubaortic obstruction at the VSD or within the hypoplastic RV Resting subaortic pressure gradients of ≥40 mm Hg high operative mortality for the modifid Fontan procedure

65. Ventricular Morphology and Function S tandard AP and lateral projections Intracardiac anatomy and ventricular morphology by selective injection into the MVC Further measurements Ventricular end-diastolic vol­ume V entricular mass V entricular mass to end-diastolic volume ratio C oncomitant measurement of atrial filing pressures and ventricular end-diastolic pressures. Mean atrial pressures and ventricular end-diastolic pressures exceeding 14 mm Hg may reflct ventricular volume load states decreased ventricular compliance Intermediate combinations of both hemodynamic conditions .

66. Pulmonary Circulation Adequate pulmonary artery size and distribution For planning palliative surgical procedures For predicting successful definitive surgical repair T o exclude distortion or stenoses of the central pulmonary arteries and the distal pulmonary arterial distribution using cranially angulated right and left oblique views to delineate the cen­tral and distal pulmonary arteries Previously placed surgical systemic-to-pulmonary artery shunts and Glenn-type cavopulmonary artery shunts must be demonstrated angiographically to exclude pulmonary artery distortion or stenosis

67. Angiographic study of Glenn shunts to detect the presence of venous collaterals pulmonary artery stenoses pulmonary arteriovenous fistulae

68. Systemic circulation Aortic arch anatomy Ventricular angiography Selective injections to delineate the location of the aortic arch to obtain the status of the brachiocephalic branches to exclude signifiant coarctation of the aorta Exclude systemic hypertension & Coarctation Assess patency of surgically placed systemic pulmonary shunts persistent ductus arteriosus systemic pulmonary collateral vessels

69. Management

70. Medical Management PGE 1 infusion and other supportive measures before surgery S evere PS or pulmonary atresia Interrupted aortic arch or coarctation Anticongestive measures if CHF develops digoxin and diuretics

71. Surgical management General objectives of initial surgical palliation T o provide unobstructed systemic outflow U nobstructed systemic and pulmonary venous return C ontrolled pulmonary blood flow Accomplished by Aortopulmonary shunt Modified Blalock- Taussig shunt Bidirectional cavopulmonary anastomosis Glenn shunt

72. Pulmonary circulations solely dependent on aortopulmonary collaterals may require unifocalization of collaterals as a component of a staged surgical approach U nrestrictive pulmonary blood flow P ulmonary artery banding Division with creation of an aortopulmonary shunt to limit pulmonary blood flow Pulmonary banding has been associated with adverse outcomes after the Fontan procedure

73. A bidirectional Glenn shunt or superior cavopulmonary shunt is performed at about 6 months of age Obstructions or distortions to the pulmonary arterial tree are corrected during this intervention. Fontan procedure C ompleted between 18 months and 4 years of age

74. Initial surgical choices Blalock- Taussig shunt for cyanotic patients with PS or pulmonary atresia mortality rate 5 % to 10 % PA banding for infants with CHF and pulmonary edema resulting from increased PBF high mortality rate—around 25% or even higher major risk factor the presence or development of an obstructed bulboventricular foramen. Most infants with obstructed foramen do not tolerate the banding well. Performed only when the bulboventricular foramen is normal or unobstructed

75. Classic BTS End to side anastomosis of Subclavian to PA

76. Modified BTS Interposition of tube graft between Subclavian A and ipsilateral PA

77. Waterston’s shunt Ascending aorta to PA

78. Pott’s shunt Descending Aorta to PA

79. If the bulboventricular foramen is too small Damus -Kaye- Stansel operation P referred procedure in the absence of pulmonary or subpulmonary stenosis. This is combined with Blalock- Taussig shunt, single ventricle to PA (Sano) shunt or bidirectional Glenn shunt Fontan -type operation can be performed later E nlargement of the bulboventricular foramen by a transaortic approach and without cardiopulmonary bypass. Performed especially when PS is present. The mortality rate is 15 % Surgery for interrupted aortic arch or coarctation should be performed, if present.

80. Second-stage surgical palliative procedures B idirectional Glenn operation (or bidirectional cavopulmonary connection) carried out between the ages of 3 and 6 months H emi- Fontan procedure

81. BDG E nd-to side anastomosis of the divided superior vena cava to the undivided pulmonary artery

82. After the second-stage surgical procedure C hild is followed up with attention to the O 2 saturation. Initially there is a remarkable improvement in O 2 saturation (approximately 85 %) Gradual deterioration in O 2 saturation may occur in the months postoperatively Opening of venous collaterals that decompress the upper body The development of pulmonary AV fistula If the child's O 2 saturation is 75% or less Proceed with the Fontan procedure. Cardiac catheterization by 12 months after the second-stage operation. Ideal candidates should have low mean PA pressure (<16 to 18 mm Hg) low PVR (<2 units) low end diastolic pressure less than 12 mm Hg.

83. Definitive procedures Fontan -type operation Classic: - Valved conduit between the right atrium and pulmonary artery Modified:- D irect anastomosis of the right atrium to pulmonary artery Performed at 18 to 24 months of age. Lateral tunnel Fontan procedure (also called cavopulmonary connection ) Fenestrated Fontan F enestrations in the baffle Creation of an ASD (4- to 6-mm) in the baffle or patch to provide an escape valve that allows right-to-left shunting, which may be beneficial E xtracardiac conduit modification of the Fontan procedure. If an AV valve is incompetent, it may need to be closed during surgery. The surgical mortality rate - 5% to 10%

84. Modified Classic Fontan Direct anastomosis of the right atrium to pulmonary artery

85. Intracardiac Lateral Tunnel Fontan E nd-to-side anastomosis of SVC to the undivided RPA Composite intraatrial tunnel with the right atrial posterior wall P rosthetic patch to channel the IVC to the transected SVC de Leval et al

86. Extracardiac Fontan Total cavopulmonary connections are performed as extracardiac tunnels IVC flow directed to the PA via an external conduit

87. Norwood Procedure In patients with univentricular hearts and systemic outflow obstruction, a variation of Norwood stages that culminate in a Fontan -type circulation is often indicated.

88. Norwood Procedure Stage I The MPA is divided, the proximal portion is anastomosed to the ascending aorta T he aortic arch is repaired and augmented PBF is maintained from RV via M odified BTS Gore-Tex shunt

89. Sano modification RV-to-PA shunt, using PTFE graft, rather than the Gore-Tex shunt 4 mm for patients < 2 kg 5 mm for those > 2 kg

90. Summary

91. Thank you