Shunt Procedures

These shunts all have in common the aim of increasing the pulmonary blood flow either by anastomosing a systemic artery or vena cava to the pulmonary artery. The resultant increased pulmonary flow reduces the level of cyanosis.

Blalock-Taussig Shunt

Blalock and Taussig developed their pioneering operation for blue children in 1945 and it has continued to be a very successful operation to this day. In the classical BT shunt (CBTS) the sublcavian artery is divided and anastomosed directly to the pulmonary artery allowing extra blood from the aorta to pass into the lungs.

The blood supply to the arm is reduced and this caused some children problems and so Klinner (1961) reported a modification (MBTS) using a Dacron tube stitched between the sublcavian and and pulmonary artery. Gore-Tex has been used since 1975.

This operation may be performed by alone eg in pulmonary atresia or in combination with an intracardiac procedure eg the Norwood Operation. In the immediate postoperative period shunts may be too large thereby flooding the lungs leading to difficulty weaning from the ventilator or too small – either due to technical problems or thrombosis. Heparin is usually used for 24-48 hours to reduce this risk.
In the long term the shunts may become too small because of growth of the child or the development of stenosis – often due to intimal peel. Aspirin is usually given to reduce the incidence of the latter.

Cavo-Pulmonary Shunt (Bidirectional Glenn)

This operation was undertaken in 1958 by Glenn. The superior vena cava draining blood from the head and the upper part of the body (40% total systemic venous return) is anastomosed directly to the right pulmonary artery increasing the amount of blood flow to the lungs and decreasing the venous return to the heart - relieving it of part of the volume overload. Glenn originally ligated the proximal RPA proximal to the shunt so blood only flowed to the right lung. This is no longer done and hence the current term "bidirectional" Glenn allowing blood to flow to both lungs. The shunt is usually undertaken on cardiopulmonary bypass at 6-12 months age in those unsuitable for a biventricular repair as part of a staged approach towards the Fontan circulation. The BT shunt (if present) is usually ligated unless small. If the PA is connected to the heart (always associated with severe pulmonary stenosis) then it may be left connected to provide pulsatile flow and encourage PA growth.

The Kawashima Operation is a further modification for those with bilateral SVCs. Each SVC is anastomosed to the ipsilateral pulmonary artery.

Central Shunt

The central shunt was devised to enable blood to flow more equally between the two pulmonary arteries. Additionally it is suitable for very small babies in whom the sublcavian artery or branch pulmonary arteries are too small to insert the shunt.

Potts and Waterston Shunts

These shunts are now rarely performed but many adult congenital patients were treated with them. The Potts shunt (1946) anastomosed the left pulmonary artery to the descending aorta whilst the Waterston shunt (1961) anastomosed the right pulmonary artery to the ascending aorta.

Both share the problem of distortion of the pulmonary artery and difficulty in accurately sizing the "window" between the arteries. This led to a high incidence of pulmonary vascular disease.

This page was last edited 14/2/2004

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