Atrial septal defect

Atrial Septal Defect in Children- a common congenital heart disease.

1. ATRIAL SEPTAL DEFECT Presenter: Dr. Archana Shrestha Y adav Resident Phase A

2. OBJECTIVES Introduction Embroyology Incidence and Genetic Associations Pathophysiology Types of ASD Natural History E valuation and Management

3. INTRODUCTION ASD is an acyanotic CHD characterized by defect in the interatrial septum causing a left to right flow between the atria Severity depends on : - size of defect - size of shunt - associated anomalies Resulting in spectrum from : asymptomatic to right sided overload, PAH , even atrial arrhythmias

4. EMBROYOLGY OF HEART

5. Septum formation in primitive atrium

6. INCIDENCE ASD constitutes 8-10% of congenital heart defects in children. Incidence = 56 per 100,000 live births Recent estimates are much higher (100 per 100,000 live births), likely due to increased recognition in the era of common use of echocardiography female: male ratio for secundum ASD = 3:1 For sinus venosus ASD= 1:1

7. ETIOLOGY Actual etiology of this congenital defect is unknown . Some factors may play role as there are some evidences of being association with ASD. Factors include: - Genetic factor - Environmental factor including antenatal use of teratogenic drugs, congenital infection

8. GENETICS The genetic basis of ASD is not completely understood. In the majority of cases this is a sporadic lesion , yet some homeobox gene defects have been found to explain some of the well known familial cases of ASDs, such as NKX2-chromosome-5, which has an autosomal dominant inheritence and AV conduction defect.

9. Other genetic syndromes with skeletal abnormalities HOLT-ORAM Syndrome , which is accused by mutations in the transcription factor TBX5 , essential in development of both the heart and upper limbs. ASD can be part of many other syndromes like DOWN syndrome and Noonan syndrome

10. HEMODYNAMICS Desaturated blood enters the right atrium from the vena cava at a volume of 3 L/min/m2 and mixes with an additional 3 L of fully saturated blood shunting left to right across the ASD

11. Results in : increase in oxygen saturation in the right atrium . Six liters of blood flows through the tricuspid valve and causes a mid-diastolic flow rumble . Oxygen saturation may be slightly higher in the right ventricle because of incomplete mixing at the atrial level.

12. The full 6 L flows across the right ventricular outflow tract and causes a systolic ejection flow murmur. Six liters returns to the left atrium, with 3 L shunting left to right across the defect and 3 L crossing the mitral valve to be ejected by the left ventricle into the ascending aorta.

13. Pathophysiology

14. TYPES Ostium Secundum (75-85%) Ostium Primum (10-15%) Sinus Venosus (5-10%) Coronary Sinus septal defect (1%)

15. Ostium Secundum Most common type. Defect in the region of fossa ovalis . Single or Multiple. May be associated with partial anomalous venous return most commonly of the right upper pulmonary vein.

16. Ostium Primum Situated in the lower portion of the artrial septum and overlies the mitral and tricuspid valve . Often associated with clefts in the anterior mitral and septal tricuspid valve leaflets and small VSDs.

17. Sinus Venosus Least common type. Situated in the upper part of atrial septum in close relation to the entry of the Superior venacava . Abnormal fusion between embryologic sinus venosus and atrium .

18. ACCORDING TO SIZE: In younger children – In older children Small defect : <3 mm Small defect: <6 mm Moderate defect: Moderate defect : 3 – 8 mm 6 – 12mm Large defect: >8 mm Large defect: >12 mm

19. ASSOCIATIONS Associated malformations are nearly 30% of Cases. Like : Secundum ASD ● Pulmonic stenosis ● Mitral valve prolapse ● Partial anomalous pulmonary venous connection Primum ASD ● Cleft mitral valve ● Discrete subaortic stenosis Sinus Venosus septal defect ● Partial anomalous pulmonary venous return Coronary Sinus septal defect ● Partial and total anomalous pulmonary venous return ● Persistent left superior vena cava

20. SYMPTOMS AND SIGNS Vary with the size of defect. Small defect : Asymptomatic and is usually diagnosed during a routine health check up. Large defect : Symptomatic and patients usually present with Failure to thrive. Easy f atigability. Increased perspiration Recurrent Pulmonary infections . Platypnea Orthodeoxia

21. On examination General examination Appearance: Usually normal Heart rate: Normal Respiratory rate: Normal Weight and height: may be less than 10 th centile.

22. Precordium Inspection: Slight prominence of precordium Palpation: Apex beat may be shifted to left P2 may be palpable Left parasternal heave may be present

23. Auscultation: S1 is normal S2 is widely splitted and fixed Ejection systolic murmur , medium pitched, soft, grade 1-3/6 & best heard at left 2 nd & 3 rd ICS A diastolic flow rumble across the tricuspid valve region.

24. INVESTIGATIONS Routine tests : ( CBC, septic screening, s.electrolyte , s. creatinine, blood grouping, coagulation profile, etc ) should be done before management. Diagnostic Investigations includes- -X-ray - Ecg -Echocardiography -Sometimes cardiac catheterization

25. Xray Findings Cardiomegaly RA enlargement RV enlargement Full pulmonary conus Increased pulmonary vascular markings Plethoric lung fields

26. ECG Enlarged ‘p’ wave indicating Right atrial hypertrophy rsR ’ seen and tall R wave Indicating RBBB and RVH Also note that the aVF is predominantly upwards as compared to Lead I indicating Right Axis Deviation LAD with rSR ’ in V1 is suggestive of Ostium primum defect

27. Associated lesions- -Right atrial and RV enlargement with diastolic flattening and paradoxical IVS motion are evidence of RV volume overload and a significant left- to-right shunt , - mitral valve prolapse, -cleft mitral valve, -anomalous pulmonary veins. Contrast echocardiography with intravenous agitated saline may be used to confirm the presence of a shunt if color Doppler are not conclusive.

28. RA LA RV Echocardiogram Primary diagnostic imaging modality for ASD. Provides: - exact localization of ASD - size of ASD - measurement of septal rims - Confirmation of the shunt - Abnormal motion of ventricular septum. - Associated lesions can be identified

29. Cardiac catheterization Patients with the classic features of a hemodynamically significant ASD on physical examination and chest radiography, in whom echocardiographic identification of an isolated secundum ASD is made, need not undergo diagnostic catheterization before repair, with the Exception: an older patient, in whom pulmonary vascular resistance may be a concern.

30. NATURAL HISTORY In patients with an ASD < 3 mm in size diagnosed before 3 months of age, spontaneous closure occurs in 100% of patients at 1½ years of age. Spontaneous closure occurs more than 80% in patients with defects between 3-8 mm before 1½ years of age. An ASD with a diameter > 8 mm rarely closes spontaneously.

31. Most children with an ASD remain active and asymptomatic. Rarely, congestive heart failure (CHF) can develop in infancy. If untreated, pulmonary hypertension and subsequent CCF may develop during or after third decade, and reversal of shunt may occur ( rare), it may be progressive with pregnancy With or without surgery, atrial arrhythmias (flutter or fibrillation) may occur in adults.

32. Infective endocarditis does not occur in patients with isolated ASDs. Cerebrovascular accident, resulting from paradoxical embolization through an ASD, is a rare complication . Mitral stenosis may occur as a result of rheumatic fever in a case of ASD ( Lutembacher syndrome).

33. COMPLICATIONS OF ASD Right sided heart failure Frequent pulmonary infections Flow-related PAH Pulmonary vascular obstructive disease Paradoxical embolism Tricuspid and mitral insufficiency Atrial arrhythmias—atrial flutter, atrial fibrillation, and Sick Sinus Syndrome.

34. MANAGEMENT Patients with small shunts and normal RV size are generally asymptomatic and require no therapy but need longtime follow up for spontaneous closure. Moderate to large shunt and/or symptomatic ASD should be managed with following strategies: - Medical therapy - Interventional therapy - Surgical therapy

35. Medical management Aim to reduce volume overload and to strengthen functions of heart muscles. Symptomatic children : Diuretics: - These agents relieve ventricular overload, peripheral and pulmonary congestion Digoxin: -Helps to strengthen the heart muscle, enabling it to pump more efficiently

36. Afterload reducers: - Enalapril - Captopril Exercise restriction is no necessary Prophylaxis for infective endocarditis is not indicated Atrial arrythmias : Appropriate Antiarrhythmic drugs. Atrial fibrillation : Antiarrhythmic drugs + anticoagulants.

37. Irreversible PAH : dobutamine , calcium channel blockers (high dose), diuretics, prostacycline , sildenafil or oxygen therapy . Treatment of Other complications, like- pulmonary infections, thrombo - embolic events or heart failure should also be treated accordingly.

38. Interventional therapy

39. Closure of ASD : In patients with small secundum ASDs and minimal left-to-right shunts without right ventricular enlargement, closure is not required Indications of ASD closure- All symptomatic patients Asymptomatic patients with- Qp : Qs ratio of at least 2 : 1 Right ventricular enlargement Time of closure- usually after the 1st yr and before entry into school

40. Interventional therapy Indication: Echocardiographic evidence of ostium secundum ASD Clinical evidence of RV volume load ( i.e. 1.5:1 degree of left to right shunt or RV enlargement ) ASD diameter less than 36 mm Presence of sufficient rim of tissue( at least 5 mm) Patient with fenestrated Fontan lateral tunnel if temporary balloon occlusion is tolerated

41. Contraindication: Sinus venosus , coronary sinus or primum ASD Extensive congenital cardiac anomaly. Known sepsis within one month prior to implantation or any untreated systemic infection prior to device placement. Bleeding disorder, untreated ulcer or any other contraindications to aspirin therapy. Demonstrated intracardiac thrombi on echo. Any patient whose size or condition would cause to be a poor candidate for cardiac catheterization.

42. Different ASD closure devices: Clamshell(TM) device Buttoned device Angel wings(TM) device Atrial septal defect occluder system device

43. Advantages of device closure- It is safe and cost-effective than surgery Successful implantation rates more than 96%, Fewer complications: Major<1 %, Shortened hospitalization Avoidance of pain and residual thoracotomy scars Reduced need for blood products . Disadvantages of device closure- Higher rate of small residual leak

44. Complications of Device Closure: Device misalignment/embolization Device erosion of atrial wall or aorta Device impingement on adjacent structures AV valve, Coronary sinus, SVC, Pulmonary veins, Aorta Infection including endocarditis Thromboembolic Complication Allergic reaction Valvular regurgitation Residual shunt

45. Follow– Up After Device Closure: Clinical - assessment of symptoms of arrhythmia, chest pain, or embolic events. Echocardiography surveillance - device position, residual shunting, and complications such as thrombus formation or pericardial effusion. Frequency of follow-up echocardiography - usually at 24 hours, 1 month, 6 months, and 1 year and at regular intervals thereafter.

46. Surgical management

47. Surgical management Surgical closure has been the “gold standard” form of treatment of ASD Surgeons need proper training and expertise in performing operations. The surgical approach can be by right thoracotomy or sternotomy, and more limited incisions are feasible with either approach.

48. Procedure - Simple suture or patch closure Timing - Surgery is usually delayed until the patient is 2 to 4 years of age because the possibility of spontaneous closure exists. In infancy- If CCF not respond to medical management

49. Indication: ASD with RA and RV enlargement with / without symptoms. ASD minimum diameter > 10 mm on echocardiography A sinus venosus , coronary sinus or primum ASD Chronic atrial arrythmia with ASD (concomitant Maze procedure) Contraindication : Patients with severe irreversible PAH & reverse shunt SPO2 < 90 %

50. Advantages of Surgery- Can be performed in any type of ASD Associated anatomical abnormality can be corrected concurrently. Excellent late outcome. Disadvantages of Surgery- Costly Needs expertise hands Prolong Hospital stay pain and residual thoracotomy scars

51. Complications: ● Pericardial effusion / constriction ● Residual shunt ● RV systolic and diastolic dysfunction ● Pulmonary artery pressure ● Mitral regurgitation ● Pulmonary vein stenosis or caval vein stenosis (sinus venosus defects) ● Arrhythmia ● Tricuspid regurgitation

52. Follow – Up After Surgical Closure: Early postoperative follow-up: -Symptoms of undue fever, fatigue, vomiting, chest pain, or abdominal pain ( may represent post pericardiotomy syndrome with tamponade and needs immediate evaluation with echocardiography .) Annual clinical F/U : (if following conditions persist or develop) - PAH. - Atrial arrhythmias. - RV or LV dysfunction. - Coexisting valvular or other cardiac lesion

53. PROGNOSIS: Patients generally survive up to adulthood without surgical or percutaneous intervention mainly with small to moderate size ASD and many patients live to advanced age. The results after surgical or device closure in children with moderate to large shunts are excellent. Mortality is less than 2% after surgical closure of uncomplicated ASD Mortality and morbidity increase with pulmonary vascular disease

54. TAKE –HOME MESSAGES Atrial septal defects are relatively common CHD Early symptoms are usually rare except very large deffect . Any kind of closure is safe and effective and associated with improved life expectancy A comprehensive treatment plan should include input from the primary care provider, the Paediatric Cardiologist and the Paediatric Cardiovascular surgeon.

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