Interventional Cardiology

Diagnostic and interventional cardiac catheterisation

Cardiac catheterisation is a minimally invasive way of acquiring information about the heart and circulation. Fine flexible tubes (cardiac catheters) are passed into the vessels and heart under x-ray guidance. The catheters are usually placed from the vessels at the top of the groin although the vessels in the neck, arm and liver may also be used. In children and infants the procedure is carried out under general anaesthetic and can be carried out under local anaesthetic in older children and adults. Information about the circulation is obtained by measuring the pressure and oxygen saturations at various points in the circulation. X-ray pictures of the heart and vessels can also be undertaken by injecting contrast (a type of dye that can been seen on x-ray) a process known as angiography. Two to three decades ago this process of diagnostic cardiac catheterisation was used commonly to work out the precise problem even in relatively straightforward congenital heart disease. Advances in other imaging techniques, in particular echocardiography, CT scanning and MRI has allowed the majority of congenital heart disease to be diagnosed without a cardiac catheter. However diagnostic cardiac catheters continue to be vital in providing additional information particularly when accurate pressure information is required to plan management and for complex cases.

Over the same period of time there have been huge advances in therapies which can be delivered via cardiac catheter- interventional cardiac catheterisation. In some cases this is as a less invasive direct alternative to open heart surgery and in others procedures are carried out in patients who are too high risk for surgery or in whom there is no surgical option. Commonly carried out procedures include passing a balloon over a wire across a narrow valve or vessel and then inflating the balloon to relieve the narrowing (balloon valvuloplasty/ angioplasty), opening up a narrowed vessel with a stent mounted on a balloon and deploying devices passed through the catheters across holes in the heart or abnormal vessels to seal them off. More recently certain valve replacements (in particularly the pulmonary valve) can be carried out interventionally in the catheter lab by passing a folded valve mounted on a stent to the appropriate position and inflating it there.