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 Patent Ductus Arteriosus (PDA)

The ductus arteriosus is the vessel leading from the bifurcation of the pulmonary artery to the aorta distal to the left subclavian artery. It is open normally in the fetus but closes functionally in I -2 days after birth. It closes anatomically in 10 - 21 days. In PDA there is a failure of this vessel to close, resulting in a continuous AV shunt.

Associated Lesions 

A. VSD

B. ASD

C. Aortic stenosis

D. Coarctation of aorta

E. Endocardial fibroelastosis

F. Pulmonary stenosis

Associated Syndromes 

A. Downs Syndrome Trisomy 21

B. Congenital Rubella Syndrome (Deafness, Cataract and PDA or Pulmonary Stenosis)

C. Fetal Hydantoin Syndrome due to phenytoin.

Diagnosis 

Symptoms: Recurrent respiratory infection in childhood, dyspnea and angina. 

Signs 

A. Signs of wide pulse pressure

B. Pulsations of pulmonary artery and pulsations in suprasternal notch

C. Heaving apex beat

Central Venous Catheter: Indication Anatomy Preparation Technique Procedure Complications

D. Gibson's murmur: It is a continuous murmur increased at the end of systole and early diastole and accentuated by exercise and expiration. It is best heard in the pulmonary area or higher up (below the clavicle in 2"d intercostal space). It is 'machinery' or 'train in tunnel' in character. It is absent:

l. Below the age of 3 years

2. In heart failure

3. If there is right to left shunt

E. Mid-diastolic mitral flow murmur may be heard.

F. If there is pulmonary hypertension there will be signs of pulmonary hypertension as described in mitral stenosis. In addition, there will be:

     l. Differential cyanosis i.e. cyanosis more in the lower limbs than upper limbs, more apparent after a hot bath

    2. Disappearance of Gibson's and mitral mid-diastolic murmurs

Investigations of Patent Ductus Arteriosus (PDA)

I. ECG

1. Normal in infancy

2. Left ventricular and left at rial hypertrophy

3. If associated pulmonary hypertension there will be right ventricular hypertrophy 

4. Prolonged PR interval

5. Atrial fibrillation sometimes

II. X-rays

l. Left atrial and left ventricular hypertrophy

2. Marked pulmonary plethora

3. Aortic knuckle prominent

4. Notch between the aortic knuckle and the pulmonary artery is obliterated

5. Calcified ductus

Echocardiogram would demonstrate the patent ductus and color Doppler would suggest the direction of flow.

Complications of Patent Ductus Arteriosus (PDA) 

A. Pulmonary hypertension

B. Infective endocarditis

C. Congestive cardiac failure

Differential Diagnosis of Patent Ductus Arteriosus (PDA)

This includes all causes of continuous murmur as given above. 

Treatment of Patent Ductus Arteriosus (PDA)

A. Medical Treatment:Indomethacin - O.lmg/kg/ dose 12 hourly for 3 doses (if diagnosed within

2 weeks of birth)

B. Surgical Treatment: Ligation and excision of the ductus. All these cases require surgery unless contraindicated.

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Contraindications of surgery

Absolute contraindications:

l. Eisenmenger's complex

2. Where ductus is compensatoryalongwith:-

a. Preductal coarctation

b. Transposition of great vessels

c. Tricuspid or pulmonary atresia

Relative contraindications: 

l. Infective endocarditis (for 3 months).

2. Congestive cardiac failure.

C. Trans-catheter closure - using coils, plugs or umbrellas