Long term central venous catheters for haemodialysis causing an extra-cardiac right-to-left shunt.

Central venous catheters can provide long-term access for haemodialysis patients who cannot have an arteriovenous fistula or graft fashioned. However, long-term central venous catheter use for haemodialysis may lead to complications including central venous stenosis, and superior vena cava obstruction in its worst form. Here, we describe the case of a patient on haemodialysis via central venous catheters for over 20 years, in whom chronic superior vena cava obstruction led to the development of mediastinal collateral vessels. These drained deoxygenated systemic venous blood into the oxygenated pulmonary venous system. Over time, this caused a significant right-to-left shunt and resulting hypoxaemia. This is the first reported case of central venous catheters used for haemodialysis resulting in an acquired, extra-cardiac, right-to-left shunt.