tricuspid atresia

 Tricuspid Atresia

Tricuspid valve fails to develop and no communication exists between right atrium and right ventricle.

Pathophysiology

Tricuspid valve fails to develop.

No communication between right atrium and right ventricle.

Right ventricle is usually hypoplastic (small) and Atrial septal defect or patent foramen ovale is present.

Ventricular septal defect is commonly present.

If presence of tricuspid Atresia.

Unoxygenated blood returning to right atrium cannot pass into right ventricle.

Blood passes through atrial septal defect or patent foramen ovale into left atrium and left ventricle.

From left ventricle, portion of blood flows through ventricular septal defect (if present) into small right ventricle and pulmonary circulation.

If no ventricular septal defect present.

Then blood flow to lungs is through patent ductus arteriosus.

Clinical feature

Infant with tricuspid Atresia - usually cyanotic at birth.

If no ventricular septal defect present then, infant is totally dependent on PDA for pulmonary blood flow.

After closer of PDA, infants develops symptoms-

1. Profound cyanosis

2. Hypoxic spell

3. Tachypenea

4. Delayed growth

5. Acidosis

6. Clubbing of nails

7. Congestive heart failure- in presence of large ventricular septal defect which leads to excessive pulmonary blood flow.

Diagnostic Evaluation

1. Cardiac examination - Reveals murmur, heart defect such as ventricular septal defect and patent ductus arteriosus.

2. Electrocardiogram

ECG reveals right and left atrial enlargement, decreased and absent right ventricular pressure and left ventricular hypertrophy.

3. Chest radiograph

Heart size normal or increase pulmonary vascularity usually decreased.

4. Echocardiogram

Absence of tricuspid valve, size of right ventricle and presence of other cardiac defect such as ventricular septal defect - identified with 2D echocardiogrphy.

Therapeutic Management

1. Medical management

Infant who are dependent on patent ductus arteriosus for pulmonary flow, given continuous infusion of prostaglandin (PGE1), to maintain patency of ductus arteriosus untill systemic to pulmonary shunt surgery performed.

2. Surgical management

1. Palliative surgery

a. Blalock- taussig shunt

Right or left subclavian artery connected to pulmonary artery of same, allow for increased blood flow to lung.

b. Balloon Atrial septostomy

Interartrial communication because right atrium has no blood flow.

Infant with VSD, adequate pulmonary blood flow, not require systemic to pulmonary shunt.

2. Corrective surgery

Total repair of tricuspid Atresia involve creation of communication between right atrium and pulmonary artery or right ventricle by direct anastomosis or conduit.

Any ASD or VSD, if present or any previous systemic to pulmonary shunts like blalock taussig shunt or closed. Repair known as Fontan procedure (done at 4-5 year's of age).

Fontan procedure

Inferior vena cava (IVC) disconnected from the heart and connects it to the pulmonary artery using a conduit (tube). It direct anastomosis of the right atrium to the main pulmonary artery through makes a small hole between the conduit and the right atrium.

Post - operative complications

Complication of surgical repair include-

1. Congestive heart failure

2. Renal failure

3. Residual VSD

4. Conduit obstruction

5. Dysrhythmias

6. Infective endocarditis