FOLLOW UP OF rTOF

1. Long term management
of post TOF/ICR (rTOF)
Murtaza Kamal
Aug 20, 2019
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2. Scope of the talk
• Introduction
• Post op pathophysiology
• RV in rTOF
• RV-LV interactions
• Assessment of rTOF: Imaging modalities
• Aortic root in rTOF
• Arrhythmias and SCD risk
• Pulmonary valve replacement
• Neurodevelopmental outcomes
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3. Lets not forget …
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4. Introduction
Sx repair: Imp landmark: 1954 Lillhei n team
Complete repair: Dramatically alters life
expectancy; not curative: Anatomically,
physiologically, electro-physiologically abnormal
Long term survival: Not equal to general population:
Annual mortality risk increases by 0.1%per decade
rTOF: Disease needing follow up
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5. Natural n Unnatural h/o
TOF
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6. Abnormalities in rTOF
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7. Re-interventions in
rTOF
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8. PR
Key hemodynamically significant lesion: Progressive RV
dilatation+ Ventricular dysfunction
Increases with time—> RV volume overload (exacerbated by
distal PA stenosis)
Indications/ methods/ optimal timing of PV replacement:
Debatable
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9. Determinants of PR
Regurgitant orifice area
RV compliance
Diastolic pressure difference b/w MPA+ RV
Capacitance of PAs
Duration of diastole
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10. Determinants of PR
cont…
Torricelli principal:
PR Volume= ROA X C X DT X (P2-P1)
ROA: Regurgitation orifice area
C: Constant (empiric number)
DT: Diastolic time
P2-P1: Mean diastolic pressure
difference b/w MPA and RV
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11. PR pathophysiology
PR depends on:
Diastolic PA/RV gradient: Very little
PV orifice size
PA diastolic pressure depends on vessel recoil after
systole and transmitted pressure from LA
RV diastolic pressure depends on RV compliance
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12. Why is post op PR
progressive?
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13. RV post TOF repair
Pathophysiology of RV remodelling in response to altered hemodynamic
conditions after rTOF: Similar to response of LV to ch. volume overload
Differences with regard to:
Chamber geometry
Myofiber artitecture
Chamber contraction pattern
Coronary artery anatomy and flow dynamics
Disposition of conduction system
Dependency on LV size and function
Although RV function impacts LV function: Reverse much more
pronounced with 63%of RV pressure rise accounted for by LV contraction
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14. RV post TOF repair
cont…
Relief of RVOT obstruction involves:
Incision of infundibular free wall
Resection of obstructive muscle bundles
Disruption of PV with partial/complete excision
Placement of an outflow patch , often
extending to the plane of PV into MPA
Conduit: RV to PA
VSD patch closure (can impair TV function)
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15. rTOF issues
PR:
Akinesis/ Dyskinesis of RVOT
Outflow patch aneurysm
RV free wall fibrosis
Conduction delay
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16. Insights from CMR
Similar to LV function in severe chronic AR—> Once
compensatory mechanisms of RV fails, Mass: volume ratio
decreases, ES volume increases, EF decreases
Kurotobi et al: Demonstrated association b/w increase in RV
wall stress (afterload), decreased RV EF and symptoms in
rTOF
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17. rTOF: Factors
affecting RV mechanics
Size of outflow patch
RV fibrosis
Impaired RV diastolic function
LV dysfunction
Prolonged conduction time
Dyssynchrony of RV contraction
Older age of repair
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18. RV in rTOF
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19. RV-LV interaction after
TOF repair
RV+ LV functions in series: Similar net outputs in absence of
shunts
Bernheim: 1910
Bernheim effect: Alterations in size+ functions of LV—>
Adversely impact geometry+ function of RV eg: Sev MR—>
Displaces IVS into RV—> Elevates JVP
Reverse Bernheim effect: Alterations in size+ functions of
RV leads to LV dysfunction
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20. RV-LV interaction after
TOF repair cont…
Superficial spiralling layer of RV myofibers—> Continuous with
superficial layer of LV; Deep layer continuous through IVS
V-V interactions: Ventricles share myofibers, septum, coronary
blood flow, pericardial space
RV volume load—> Septum shifts towards left—> Leftward
shift of LV pressure- volume loop—> Reduced LV volumes
Progressive RV dysfunction—> LV function deteriorates
Ventricular dyssynchrony (Both intra+ inter ventricular):
Contributes to adverse RV-LV interactions
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21. Physiological factors
linking 2 ventricles…
Blood moved through lungs by RV—> LV preload+ CO
PS+ PR: Threatens LV preload+ CO
Change in shape/ size of RV—> LV also alters
Trans septal pressure gradient: Determines position of
ventricular septum at ED
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22. Pre op factors affecting
LV function in rTOF
Abnormal CA anatomy
Prolonged periods of deep cyanosis
LV volume overload: Palliative shunts
LVEF on CMR late after TOF repair influenced by:
RVEF
Duration of palliation pre repair
AR
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23. rTOF: How to follow
up?
History:
Effort intolerance, palpitation, neuro
developmental+ psychiatric evaluation
Examination:
Growth+ development, BP, JVP (Commonly raised-
Restrictive physiology, Prominent V waves if TR)
Cardiomegaly, RV outflow pulsations
Aortic enlargement
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24. ECG
Rhythm: Sinus/ CHB/ A flutter/ PCVs VT
Axis: RBBB/ QRS duration/ QRS fragmentation
Rt axis: Common, lt axis due to inlet VSD or post op
bifascicular block
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25. CXR
Heart size
Infundibular enlargement, RVOT aneurysm
RA enlargement in severe TR
Ascending aortic enlargement
Lung vascularity: Differential vascularity from PA
stenosis, collaterals
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26. ECHO assessment of
rTOF
Residua/ Sequelae/ complications
Residual VSD/ RVOTO
PA stenosis
PR
TR
RV/ LV function
Ascending aorta
Collaterals
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27. Doppler study
Non invasive hemodynamic information: Useful for
decision making
Assessment of PR severity
Diastolic flow reversal—> Severe PR, esp if in BPAs
PHT (<100msec)+ Jet annulus ratio (>1/3): Best
correlates with CMR severity
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28. 3D ECHO
Better assessment of PV morphology
Better characterisation of pulmonary flow
Underestimates RV volumes and EF
Low spacial+ temporal resolution
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29. CMR
Gold standard
Timing a major challenge in India: Availability and
cost
PR fraction
PR volume
RVEDV, RVESV
RV/LV Ratio
RVEF
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30. Late issues
Interventions: PA stenting, PV replacement,
Pacemaker implantation
Endocarditis
Contraception/ Pregnancy after rTOF
Neurodevelopmental outcomes
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31. Indications of PVR in patients with
rTOF/ similar physiology with
moderate- severe PR (RF≥25%)
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32. For symptomatic
patients…
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33. Special situations
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34. Benefits of PV
replacement
RV systolic pressure decreases
RVH decreases
RV dilatation decreases
TR decreases
RVEF increases
CI response to exercise increases
Exercise tolerance increases
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35. Life after PV
replacement
4.4/100 patient years need interventions
75%: Restenosis
15%: Endocarditis
2%: PR
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36. Dr. Phillip Bonhoeffer
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37. Melody PV
16+ 18 mm
22F Delivery sheath
Medtronic Inc.
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38. Edwards Sapien PV
23+26 mm
22 and 24 F del sh.
Edward’s life sciences
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39. 39

40. Arrhythmias after
rTOF
Bradyarrhythmias:
1% CHB after TOF repair—> May recover
Delayed recovery may predict late CHB+SCD
SV arrhythmias:
30% in late f/up
A fib, A flu, focal or re entrant recurrent
tachycardia—> All occur+ cause morbidity—>
CHF/ stroke/ VT/ reoperation/ mortality
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41. Electromechanical
interactions
Arrhythmias+ SCD: MCC of death post rTOF
Risk factors for SCD (1-5%):
Older age at sx repair
Moderate- severe PR
Sy+ Di dysfunction
Prolonged QRS interval (>180 msec)
CHB beyond 3rd POD
Repair via atriotomy
Male sex
Advanced NYHA class
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42. Electromechanical
interactions cont…
All pathophysiological mechanisms for arrhythmias present
Electrical instability:
Anatomical modifications following sx
Mechanical events like ventricular dilatation+ stretching
Abnormal fibrous tissues at different sites in RV/LV
Fibrofatty substitution around sx scar- Anatomical substrate
for re-entrant tachycardia
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43. Contraception/
pregnancy after rTOF
Early education to teenage girls
Recurrence risk/ males too
Mostly can choose from full range on contraception
Cautions with combined hormonal preparations in those with
significant vent dysfunction/ atrial arrhythmias- associated risks
of TE risks of oestrogen
Pregnancy generally well tolerated
Risks of pregnancy depends on severity of residual lesions, deg
of vent dysfunction, likelihood of developing arrhythmia
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44. IE
Rare after rTOF; but frequency increases after PV
replacement
Patients educated/ oral hygiene
Prophylaxis for those with conduits+ prosthetic
valves
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45. Aortic root post TOF
repair
Fetus with TOF: Normal aortic root diameter at
diagnosis—> Serial measurement—> Accelerated
growth (esp with severe RVOTO)
At birth: Absolute diameter of aorta increased
Increased volume load on developing aorta
?Histologic/ elastic abnormalities
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46. Aortic root dilatation
Can cause aortic insufficiency in adults: AV
replacement needed
Extremely rare: Aortic dissection
Studies revealed regression of aortic sinus years
after rTOF

47. Neurodevelopmental
outcomes
Long term f/up: Some impairment in cognitive+
motor development
All pts of rTOF: Appropriate developmental
behavioural surveillance+ screening
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48. 22q11.2 micro deletion
in TOF
Common association (8-15%)
May be diagnosed for 1st time in adulthood
Dyslexia, behavioural abnormalities+ psychiatric
disorders: Common
Genetic diagnosis allows early recognition+
treatment of non cardiac problem
AD: 50% risk to offspring
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49. So summing up with take home
message:
Current results of TOF repair
Child with TOF expected corrective surgery by 6 months: >96%
survival to hospital discharge
During childhood: 5% reoperation; 6% catheter interventions
PV replacement needed for 0.8%/year—>TOF-PA or TOF-APV
more likely
For a 30 yrs old rTOF: Annual risk of death 0.5%( Normal risk
0.15% males; 0.06% females)—> Risk increases by 0.1%/ decade
Increasing adverse outcomes with age: Related to
pathophysiology of rTOF
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50. Thank you…
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