Patent Arterial Duct

London Paediatric Cardiologist - Patent Arterial Duct

Overview

The ductus arteriosus is normal finding in all people in fetal life (before birth). It is a ‘safety feature’, that acts as a bypass channel between the body and lung circulations. The ductus arteriosus is biologically programmed  to shut when babies are born at full-term in response to breathing air. It usually shuts in most people, in the first few days - to - first few weeksafter birth. If it remains open it is referred to as a Patent Ductus Arteriosus or (PDA). A PDA acts as an additional (and abnormal) source of lung blood flow. As a result, there is extra strain on the left-hand side of the heart, which collects and deals with this extra volume of blood.

Presentation

Presentation is variable depending upon the size of the PDA, age of the child and or presence of other cardiac problems. Small ducts

Small ducts - usually come to medical attention following the incidental detection of a murmur at routine health checks. There are no symptoms attributable to them.

Moderate sized ducts - may come to medical attention due to a murmur but also from symptoms of heart failure such as breathlessness and poor feeding. Growth may be impaired and children may be more susceptible to chest infections.

Large ducts - may present with features of severe heart failure. These symptoms may include, breathlessness at rest, failure to thrive and multiple respiratory infections

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Investigations

The diagnosis is made by echocardiography, which is able to visualise the PDA, aorta and pulmonary blood vessels. The size and flow characteristics across the PDA are determined, together with overall haemodynamic effect on the other cardiac structures. An electrocardiogram (ECG) is also performed to assess for dilatation of the left ventricle.

Treatment

The treatment your child will need will depend upon the size of the PDA and any other heart problems they might have.

a)No treatment needed - Tiny PDA’s that are not audible even with the use of a stethoscope are too small to cause any haemodynamic effect and are not associated with any medical problems. Patients may be discharged from further cardiac care.

b) Key-hole procedure (cardiac catheterisation with PDA device occlusion) - For haemodynamic and audible ducts, If the child is a year of age, a catheter procedure may be employed to occlude it. This approach avoids the need for cardiac surgery. A short anaesthetic is given, after which a cannula (or drip) is sited into the blood vessel in the groin. A thin tube (catheter) is then advanced into the leg and then towards and into the heart using special x-rays. A special catheter plug is then deployed across the PDA thereby occluding it. The PDA device remains fixed in position within the ductus. The procedure lasts approximately 2 hrs and patients are discharged home the same day.

c) Cardiac surgery - Child Heart Surgery is reserved for haemodynamically important lesions that are not amenable to catheter intervention, if for example the duct is very large, or baby very small. The aim of surgery is to ligate (tie-off) the duct and remove this abnormal source of blood flow. This type of operation is usually very straightforward and does not require the use of cardio-pulmonary bypass. Commonly, the operation can be performed by performing a small incision at the side of the chest (under the armpit) avoiding a scar on the front of the chest.

Follow Up

The long-term outlook for PDA’s is very good irrespective of the strategy used to close the hole (catheter device closure or cardiac surgery). Further surgical or catheter procedures are not usually required and children lead normal healthy lives.