Management of Tetralogy of Fallot

Surgical management of TOF

1. SURGICAL MANAGEMENT OF TETRALOGY OF FALLOT Dr.ANUJ MEHTA

2. Blalock and Taussig described the first systemic artery-to-pulmonary artery shunt in 1945 Lillehei and Varco (1954) first repair by an open-heart procedure. Surgical mortality decreased from 50% in the late 1950’s to < 2% in the modern surgical era Residual anatomic and haemodynamic abnormalities are nearly universal. Repaired TOF, with considerable cardiac and non-cardiac disease burden, is growing rapidly. Evolution of surgical repair of TOF

3. Shunt Anastomosis Year BT SCA- PA shunt Classical-1944
Modified- 1982 Pott’s Descending aorta-LPA 1946 Davidson’s Direct anastomosis MPA-> aorta 1956 Waterston Ascending aorta- RPA posterior to SVC 1962 Waterston- Cooley Ascending aorta- RPA anterior to SVC 1966 Gazzaniga Aorta to PA using PTFE tube 1976 Melbourne Direct end to side anastomosis of PA to ascending aorta

4. BT SHUNT De Leval ,1982 @ Great Ormond Street

5. INDICATIONS : CCHD not fit for ICR, with severe symptoms. TOF with pulmonary artery atresia TOF with- unresolved spell Age <6 months with low weight/ failure to thrive/ repeated spells. Hypoplastic pulmonary arteries. Underdeveloped LV (<60% of normal) Mitral valve annulus < -2 Z Institutional criteria for performing ICR. Mitral valve annulus <-2Z

6. CLASSICAL MODIFIED Historical current Prosthetic material - + Dissection ++++ ++ Subclavian artery sacrificed preserved Upper limb ischaemia + _ Anastomosis opposite to arch any side Take down challenging easy Shunt blockage + ++ Growth potential ++ _

7. MBTS Preferably on same side longer length of SCA available less chance of damage to RLN. Approach- right/ left thoracotomy median sternotomy- (+) significant desaturation (CPB) ( - ) adhesions during redo PTFE graft size 2-4 kg - 3.5 mm 4-5 kg - 4 mm >5 kg - 5 mm BUT, ultimately - SCA size

8. Causes of bradycardia RPA absent/ ostial stenosis/hypoplastic/nonconfluent Vagus nerve included in clamp. Signs of good shunt Graft sweating thrill over PA Improved saturation by 10-15% Fall in diastolic B.P. Heparin is NOT reversed, unless excessive bleeding

9. COMPLICATIONS Early shunt blockade oversize-heart failure undersize- inadequate perfusion bleeding seroma kinking of shunt limb ischaemia- CBTS Late distortion of PA Chylothorax Disparity in arm- CBTS Horner’s syndrome

10. m anagement of blocked BT shunt ??????? when to suspect ??????? Significant desaturation , shunt murmur (-) EtCO2 - falls arterial CO2 - rises More dangerous- infundibular obstruction has worsened collaterals are already closed. Resuscitate urgent echo GOAL- to increase SVR Decrease PVR hand ventilate sedate and paralyse Human albumin start dopamine or noradrenaline

11. Management of Pulmonary overcirculation high saturation CXR- congested lungs low mixed venous saturation acidosis low diastolic B.P. GOAL decrease SVR, Increase PVR fluid restriction reduce O2 allow PCO2 to rise gently increase PEEP Reduce vasopressors, consider vasodilators Shunt clipping to be considered

12. Indices Mc Goon ratio- angiographic [d RPA +d LPA (prebranching)/ d DTA (just above diaphragm- in systole] Normal- 2-2.5 Nakata index echo CSA [LPA+ RPA(mm2) / BSA ] Normal 330+/- 30 Kirklin index Z value

13. ICR Indications McGoon ratio > 1.5 Nataka index >200 Z value > -3 LV volume > 60% of the normal(>30 ml/m2) Absent peripheral pulmonary artery stenosis No major coronaries crossing RVOT

14. Unfavourable PA anatomy in infant Multiple VSD in infant Coronary artery crossing RVOT in infant Hypolplastic LV LVEDV < 30 ml/m2 LVED(D) <60% of normal PV annulus <-7 Z Institutional criteria Contraindications for ICR TOF

15. Technical challenges Transatrial / trans ventricular TAP/valve sparing TAP- width of patch Preserving or sacrificing RCA branches RVOT management when Anomalous coronary is present Preserving PV cusps during TAP Preserving tricuspid valve function during VSD closure. Dividing and resecting obstructing septal and parietal bands

16. Approaches RA-PA RVOT- longitudinal/ transverse PA only RA only

17. The original repairs - closure of the VSD through a large right ventriculotomy and correction of the right ventricular outflow tract (RVOT) obstruction with a transannular patch (TAP)

18. Repair of tetralogy of Fallot with separate infundibular and pulmonary arterial patches

19. Good RVOT coring PA- complete VSD, Tricuspid valve, apex of RV RA- PV, aortic across the VSD

20. Pathophysiology of RV complications post TOF repair

21. Advantages and disadvantages of various techniques

22. RV performance Acute change from pressure from pressure loaded to volume loaded RV Right ventriculotomy PR The time of greatest instantaneous hazard to survival - when the volume overload is first evident after CPB the early hours thereafter, only the functional myocardial reserve of the RV is available for adaptation.

23. To eliminate volume overload, 1) valved conduits, disadvantages are lack of durability, lack of growth, and valvular dysfunction. 2)in the short term, some groups have advocated monocusp valve insertion as an effective alternative

24. Monocuspid valve Length- distance from apex of RVOT incision to the pulmonary annulus Width- free edge equal to circumference of native annulus fixed to apex of RVOT incision and the edges sutured to muscle in continuous fashion, free edge finally opposed to the annulus Hegar dilator is passed to check adequacy of the opening A liberal transannular patch is placed above it.

25. Showing measurement of monocuspid valve. B. showing suturing technique C. Showing mechanism of action of monocuspid valve during diastolic and systolic phase.

26. Post repair RVOTO assessment Residual RVOTO After repair and seperation from CPB preferably with cannula in position post repair P RV/LV. Valve sparing - P RV/LV > 0.7 —> Transannular patch

27. Adequacy of Repair TEE/ Pressure measurement : Standard of care

28. Hypolplastic LPA - Double patch technique To be divided

29. Anomalous LAD crossing RVOT Key factor- exact course and morphology of infundibulum if Coronary high near the annulus + low infundibular obstruction + well developed infundibular chamber - procedure can be done without endangering coronary BUT , if severe diffuse hypoplasia- RV to PA conduit. Bicuspid PV- to be inspected and incision can be made through anterior most commisure- reduces PR

30. ICR for MAPCAS embolise MAPCAS on day of surgery and Sx Dissect and ligate MAPCA

31. RECENT ADVANCES Significant risk factors: Prematurity low birth weight poor PA anatomy non cardiac comorbidities. Bridging options ???

32. THANK YOU