2001.7

Double Switch Operation for Failing Systemic Ventricle

Yong Jin Kim, M.D.Department of Thoracic & Cardiovascular Surgery

Seoul National University Hospital

2001.7

Introduction

• Conventional managements of AV discordant heart ( At

rial switch operation in TGA) place morphologic right ve

ntricle & tricuspid valve in the systemic position

• The morphologic RV shows significant incidence of progressive ventricular dysfunction & TV regurgitation

• Double switch operation(conversion switch operation) as an alternative in selected patients

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Natural History of CC-TGA

1. Incidence

0.5% of CHD, slightly male predominating

2. Heart Block 1) Complete heart block

5 - 10% at birth. 10 - 15% in adolescence, 30% in adult

2) 1st or 2nd degree A-V block ; 40 - 50% at birth

3) 40% retain normal PR interval & QRS through their lives

3. Ventricular functionNot truly normal, but sufficiently good in most

Tendency to deteriorate after 2nd –3rd decade of life.

4. Effect of coexisting cardiac anomalies VSD, PS, left A-V valve incompetence

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Characteristics of Both Ventricles

1. Ventricle Shape Cylindric vs. crescent-shaped cavity

2. Contraction pattern Concentric vs. bellow-like contraction

3. Pumping action Pressure pump vs. low pressure-volume pump Its large internal surface area-to-volume ratio

4. Coronary artery supply Two system vs. one system

5. Embryology Primitive ventricle vs. bulbus cordis

6. Papillary muscles Two papillary vs. small and numerous(septophylic)

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Corrected TGA

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Corrected TGA

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CC-TGA morphologic left ventricle

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CC-TGA

morphologic right ventricle

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Operative Indications of CC-TGA

The presence of corrected TGA is not an indication for a reparative operation

1. Ventricular septal defect

· same as normal heart 2. VSD & Important PS · same as TOF 3. Left-sided tricuspid incompetence · same as mitral incompetence 4. Complete heart block

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Classic Operation of CC-TGA

1. Repair of ventricular septal defect

2. Repair of coexisting VSD & PS

· Extracardiac conduit

· Without extracardiac conduit

3. Correction of incompetent tricuspid valve

· Repair ( annuloplasty )

· Replacement

4. Fontan-type repair

Straddling, A-V canal defect & hypoplastic

ventricle

2001.7

“ Classic” Repair of Congenitally Corrected TGA and VSD

(Termignon JL, et al. Ann Thorac Surg 1996)

• From 1974 to 1994, 52 CCTGA patients• CCTGA and VSD + LVOTO(Group I) : 37• CCTGA and Isolated VSD(Group II) : 15• Tricuspid plasty or replacement

– 1 (3%) in group I, 8 (53%) in group II

• Overall operative mortality : 15% (8/52)– Incidence of postop. AV block 27% (14/52)

– Redo tricuspid plasty or replacement in 12

1. The operative mortality and the incidences of TVR & AV block are high

2. Secondary heart failure is frequent

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Tricuspid Regurgitation & RV dysfunction in CC-TGA

• High risk of TR development by the 3rd decade of life(20 to 50%)

• Most important risk factor for death after classic repairs

• Poorly supported tricuspid annulus – RV dysfunction may induce important TR

• Measurable deterioration of RV within 3 years of classic repairs

• RV dysfunction appears to be almost always secondary to

long-standing TR(Prieto, et al. Circulation.1998)

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Morphologic RV after Atrial Switch Operation

• Natural difference of ventricle– One coronary ventricle– One conduction radiation– Without well-balanced papillary muscle

• Tricuspid Regurgitation

1. Stretching of the originally noncircular tricuspid ring2. Organic damage of tricuspid valve as a results of VS

D patching

3. Failure of systolic leaflet coaptation

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Surgical Management for Failing Systemic RV

• Double Switch Operation Correction of AV discordance and VA discordance simultaneou

sly

– Senning(Mustard) + ASO

– Senning(Mustard) + Rastelli

– Senning(Mustard) + REV

• Conversion Switch Operation – previous atrial switch take-down and ASO

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Surgical Considerations

• Left Ventricular Outflow Tract• Right Ventricular Size• Atrioventricular Valves• Ventricular Function• Heart Block and Arrhythmias• Coronary Arteries• Atrial Switch Operation• Reoperations• Potential Technical Problems for ASO• Timing of Operation• Role of Left Ventricular Retraining

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Proposed Patient Selection Criteria

1. Unobstructed LV to PA and RV to aortic connections

2. Balanced ventricular and AV valve sizes

3. Septatable heart, without major AV valve straddling

4. Translocatable coronary arteries

5. Current(or recent) LV/RV pressure ratio greater than 0.7

6. Competent mitral valve with good LV function

(Karl TR, et al. ATS 1997)

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Preparation for Systemic Left Ventricle

• Naturally occurring preparation • Pulmonary Artery Banding

– age

– banding(LV retraining) duration

• Preoperative Selection Criteria– Age

– Wall thickness

– LV/RV pressure ratio

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Senning Procedure

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Mustard Procedure

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Operative Technique - Senning plus ASO

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Operative Technique – Conversion Switch Operation

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Senning Plus Arterial Switch Operation for Congenitally Corrected Transposition

(TR Karl, et al. Ann Thorac Surg 1997)

• From 1989 to 1996• 14 Senning + ASO : age ranged 0.5 to 120mo

– 1 hospital Mortality– Actuarial survival beyond 10 months : 81%– Median grade of TR : preop ¾ to ¼ postop– Normal RV function : 11/12 current survivors

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Results of the Double Switch Operation in the Current Era (Imamura, et al. Ann Thorac Surg 2000)

• From 1993 to 1998

• 22 Double Switch Operations in 27 CCTGA patients : age ranged 3mo to 55yrs– Senning & ASO : 10– Senning & Rastelli : 12– No early and late Mortality– Epicardial pacemaker insertion in 2

• Significantly improved degree of TR with normal LV and RV function

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Systemic Right Ventricular Failure After Atrial Switch Operation: Midterm Results of Conversion Into an Arterial Switch (Daebritz S

H, et al. Ann Thorac Surg 2001)

• 4 patients age 38 to 59 months of RV failure underwent arterial switch operation

• previous operation : Senning and VSD closure

• 1 late death(43.5 mo follow up) due to LV dysfunction

• Survivors : improved FS, NYHA class I – II

• Conversion switch operation is an alternative to cardiac transplantation in children

• Long-term morbidity is caused by rhythm disturbance

2001.7

Experience in SNUCH

• From 1990 to 2001• 20 double switch operations• 1 conversion switch operation • Age : ranged 1month to 16 years (mean 46months)• M : F = 11 : 9• Dx : CCTGA(with VSD, PS or PA) – 18 DORV, PS, VSD – 2 dTGA, VSD – 1 (Conversion switch after Senning procedure)

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Experience in SNUCH

• Preop. procedures– PAB : 2– LMBTS : 3– RMBTS : 1– LMBTS + RMBTS : 2– VSD closure : 2– BAS : 1– PPM insertion : 1– RV-PA conduit interposition : 1

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Experience in SNUCH

• Operative technique– Senning + ASO : 6– Senning + Rastelli : 9– Mustard + ASO : 1– Mustard + Rastelli : 1– Senning + REV : 2– Mustard + REV : 1

– * 1 conversion arterial switch operation after Senning and PAB

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Experience in SNUCH

• Operative mortality : 7 (33%)

– Number of death according to period

– 1990 - 1993 : 5 (23.8%) / 10 initial learning period LCOS 4 / sepsis 1 * 3 immediate myocardial failure– 1994 - 2001 : 2 (9.5%) / 11 LCOS 1 / sepsis 1

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Experience in SNUCH

• Complications– Postop. AV block : permanent pacemaker insertio

n in 3– Chylothorax in 4

• Reoperation in 3– Senning pathway reaugmentation– Redo Rastelli op d/t residual PS– Conduit change with Homograft

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Experience in SNUCH

• Overall outcomes– Postoperative TR : all survivors in minimal

or grade I – Preserved postoperative ventricular

function in survivors : NYHA functional class I or II

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Operative Technique

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Conclusion

• Double switch operation in selected patients in optimal anatomic & physiologic subsets has encouraging early outcomes with its theoretical advantage.

• TR and subsequent RV dysfunction represent the major risk factor for CCTGA patients.

• Conversion switch operation can be performed with acceptable risk and may provide long-term survival advantage if adequate patient preparation is warranted.