Tetralogy of Fallot C A R D I O L O G Y C L I N I C A L M E E T I N G R A C H A E L H A T T O N 1 2 / 1 0 /

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1 Tetralogy of Fallot C A R D I O L O G Y C L I N I C A L M E E T I N G R A C H A E L H A T T O N 1 2 / 1 0 /

2 Embryology

3 Embryology

4 Embryology

5 Embryology

6 What is Tetralogy of Fallot? Constellation of cardiac findings and spectrum of clinical disease A large malaligned VSD Over-riding of the aorta over the septal defect Right ventricular outflow tract obstruction Right ventricular hypertrophy

7 Historical Aspects Niels Stensen 1672 Fallot 1888 la maladie bleue 1945 first surgical treatment by Alfred Blalock, Vivien Thomas and Helen Taussig the first aortopulmonary shunt 1955 Lillihei first intracardiac repair

8 Epidemiology The most common form of cyanotic congenital heart disease Reported prevalence varies greatly between studies depending on the diagnostic techniques and morphologic classification 0.26 to 0.48 per 1000 live births 1998 study from Malta 0.8 per 1000 TOF comprises 3.5-9% of CHD No ethnic variation 80% have TOF with PS, 20% with PA

9 Recurrence risks 2.5% with one affected sibling Up to 8% with two or more siblings Risk to offspring somewhat higher % Slightly higher risk if father is affected compared to mother Depends on the specific genetic and environmental cause of the parent s defect

10 Environmental factors Environmental teratogens associated with TOF with PS Maternal diabetes Retinoic acids Maternal PKU trimethadione

11 Genetic factors Family studies have found monogenic and polygenic modes of inheritance Autosomal dominant with reduced penetrance Autosomal recessive Heterogeneous supported by the finding of different morphologies within a single family

12 Genetic factors A significant proportion of patients are found to be syndromic or to have chromosomal abnormalities Baltimore-Washington Infant Study ( ) found 11.9% of patients hade chromosomal abnormalities (Trisomy 21, 18, 13) 7.2% syndromic 2.1% multiple abnormalities 11.4% other single organ defects

13 Genetic Factors DiGeorge/Velocardiofacial syndrome DGS - conotruncal defects, aplasia of the thymus, parathyroid gland Deletion of 22q11 VCFS distinct facies, palate abnomalies, learning and speech defects and CHD 8-23% of patients with TOF have 22q11 deletion Increases the risk of associated vascular abnormalities such as right sided aortic arch Clinical phenotype highly variable

14 Alagille Syndrome Dominant inheritance Bile duct paucity with associated cardiac, skeletal and ocular abnormalities Jagged1 gene codes for a cell surface protein 10-15% have TOF Phenotype highly variable

15 Developmental Considerations Defect occurs between 28 and 50 days of gestation

16 Developmental Considerations Abnormal rotation of the conotruncus and faulty partitioning of the conotruncus Malalignment of the outlet and trabecular septum Anterior and cephalid deviation of the outlet septum Saddling of the AV across a membranous VSD Abnormal anterior septation results in the RVOT obstruction

17 Anatomy Subpulmonic obstruction Normal pulmonary artery pressures Distal obstruction to the RVOT PV apparatus uni and bicuspid Supravalvular Proximal and distal pulmonary artery bed VSD fibrous continuity between the tricuspid and aortic valves Additional VSD s may occur Large and non-restrictive equalisation of LV and RV pressure

18 Anatomy Terminology Over-riding vs double outlet Degree of over-ride varies from 15 to 95%

19 Associated Abnormalities Variations in coronary arteries LAD arising from the RCA and therefore coursing across the RVOT (5%) Large conal branch, accessory LAD (15%) Single origin (4%) Coronary-to-pulmonary artery fistulas Arch abnormalities Right sided arch in 25% Aortopulmonary collaterals Other Cardiac defects ASD/PFO in up to 83% Left SVC in 11% Anomolous pulmonary drainage, Ebstein s

20 Clinical Presentation Great variation depending on the degree of RVOT obstruction and right to left shunting Diagnosis by foetal ultrasound is now common Neonate systolic murmur or cyanosis Critical RVOT obstruction may be initially only mildly cyanotic Hypercyanotic episodes and squatting Severe, prolonged decrease in oxygen saturation due to an abrupt increase in right to left shunting Iron deficiency anaemia Changes in catecholamine levels or hypovolaemia Squatting increases SVR and reduces right to left shunting

21 Examination Cyanosis of varying degrees Clubbing Right ventricular heave Single second heart sound Systolic murmur at the upper left sternal edge Crescendo-decrescendo or plateau, harsh quality Inversely parallels the degree of RVOT obstruction Diastolic murmurs are uncommon except in APV syndrome

22 ECG Diagnostic studies

23 CXR Diagnostic Studies

24 Diagnostic Studies Haemoglobin Polycythaemia common Hct >65% can pose problems with hyperviscosity Any degree of anaemia is poorly tolerated Echocardiography Cornerstone of non-invasive diagnosis TOF Associated lesions

25 Echocardiography

26 Echocardiography

27 Cardiac Catheterization Less relevant with the improvements in non-invasive imaging Still useful in the setting of severe pulmonary artery stenoses or hypoplasia intervention Help define aortopulmonary collaterals for coil closure Pressures, saturations, cardiac output, Qp:Qs Definition of coronary arteries, right ventricular anatomy

28 MRI Emerging as an immensely valuable tool in congenital heart disease Non-invasive Accurate analysis of morphology Coronary anatomy Planning surgical strategies

29 MRI

30 Therapeutic Considerations Surgery Adequate, complete relief of RVOT obstruction Closure of the VSD Medical Assess degree of RVOT obstruction EARLY PDA Parental education re cyanotic spells All patients with right-to-left shunts are at risk of paradoxical emboli Watch for symptoms of hyperviscosity Monitor for anaemia

31 Surgical Correction Blalock-Thomas-Taussig shunt Pulmonary artery distortion Additional ventricular volume loading Surgical risk associated with thoracotomy Primary repair Cardiopulmonary bypass RVOT patch (homograft, dacron) (avoiding transannular patching) VSD patch closure

32 Surgical Correction

33 When to Operate? Natural History (Circulation. 2000;102[suppl III]:III-123-III- 129) 227 children repaired isolated tetralogy of fallot between 1993 and 1998

34 When to Operate?

35 When to Operate?

36 When to Operate?

37 When to Operate? Patients receiving a trans-annular patch tolerated the repair less well. Each of the deaths occurred in a child who received a trans-annular patch. In the multivariate model, however, a trans-annular patch was not a risk factor for prolonged time to lactate clearance, extubation, or hospital stay. Conclusion: The optimal age for elective repair of Tetralogy of Fallot is 3 to 11 months

38 Predictors of Poor Outcome Knauth et al. Heart 2006 Independent predictors of poor outcome (death, sustained VT, NYHA III/IV CCF) Late repair (>6yr old) Increased RV end diastolic volume Reduced RV and LV EF Longer QRS RVESV >45mL 100% sensitive RVEF <30% 96% specific

39 Long-Term Follow-Up 35 year survival following reparative surgery is now >85% The most typical adult patient with TOF will have undergone a complete repair Follow-up must focus on: Residual shunts or RVOT obstruction Pulmonary valve insufficiency RV dysfunction PA stenosis and distortions Arrhythmia/SCD risk 100x general population

40 Long Term Follow-Up Arrhythmia Burden (Circulation. 2010;122: ) 556 patients (54% female) Mean age 36yrs 11 centres in North America

41 Arrhythmia Burden

42 Arrhythmia Burden

43 Arrhythmia Burden

44 Arrhythmia Burden

45 Pulmonary Incompetence and RV dysfunction With the recognition that long term outcomes could be closely linked to RV function, researchers began investigating the role of PV replacement PVR reduces PI and RV dilatation but what is the impact on survival and VT? Circulation. 2009;119: Single centre control-matched cohort study 98 patients undergoing PVR for RV dilatation at least 5 years after TOF repair

46 Role of PVR following TOF repair

47 Role of PVR following TOF repair Groups were well matched according to age at review, age at repair, QRS duration, presence of LV dysfunction, most echo parameters RV dysfunction RVEDVi 196 vs 132mL/m2 PVR did not result in improved mortality nor freedom from VT

48 What are the Guidelines for Managing Adults with Repaired TOF? ESC Guidelines 2010 Adult Congenital Heart Disease Diagnostic Work-up Echo CMR CPET Holter / event monitoring Cardiac Catheterization

49 ESC Guidelines Indications for intervention AVR for severe AR in symptomatic patients or with LV dysfunction (1C) Pulmonary valve replacement in symptomatic patients with sever e PI or PS (1C) Consider PVRep in asymptomatic patients if (IIaC) Decreased exercise capacity on CPET Progressive RV dilatation or dysfunction Progressive TR RVOTO with RVSP>80mmHg Sustained arrhythmias VSD closure if significant LV volume overload or if undergoing PV surgery (IIaC)

50 ESC Guidelines Indications for EP testing / ICD Symptomatic patients with suspected or documented arrhythmia should be considered for EPS ICD as for general population. No ideal risk stratification scheme for this population. Primary prevention is controversial Risk markers RV/LV dysfunction, extensive fibrosis on CMR, QRS>180ms, significant PI, non-sustained VT on Holter, inducible VT at EPS, long-lasting palliative shunts, older age at repair

51 EPS guidelines Follow-up At least annually at a specialised GUCH centre PI RVOTO RV dilatation and dysfunction Residual VSD Aortic root dilatation and AI LV dysfunction Arrhythmias

52 Summary Tetralogy of Fallot is a broad spectrum of clinical and pathological disease Each case has to be approached individually Consideration must be given to the mode of palliation and/or repair Regular follow up is essential Utilise a range of assessment tools Watch for RV dysfunction and arrhythmias

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