Conduit

A conduit in cardiac surgery is a tube or vessel used to create a new pathway connecting one part of the cardiovascular system to another, typically to bypass an obstruction, replace a damaged structure, or reconstruct an abnormal anatomy. Conduits can be biological (such as a segment of the patient’s own vein or artery, or a preserved donor vessel called a homograft) or synthetic (such as polyester or PTFE fabric tubing).

Conduits are widely used in congenital heart surgery, where complex reconstructions may require replacing absent or abnormal connections. A classic example is the replacement of the right ventricular outflow tract (the connection from the right ventricle to the pulmonary arteries) in conditions such as tetralogy of Fallot or pulmonary atresia. Pulmonary homografts (preserved donor pulmonary valves and vessels) are preferred in these situations because they include a functioning valve to prevent backflow.

In coronary artery bypass grafting (CABG), the conduit is the bypass graft itself: a segment of saphenous vein from the leg, or the internal mammary artery from the chest wall. It is anastomosed (attached) to the aorta at one end and to the coronary artery beyond the blockage at the other, creating a new channel for blood to reach the heart muscle.

All biological conduits have a finite lifespan. Homograft conduits in children tend to calcify and obstruct as the child grows, often necessitating reoperation. Monitoring of conduit function with echocardiography and MRI is a standard part of follow-up for patients with conduit repairs.