Angiography (DSA - digital subtraction angiography) | CLINICAL CENTRE

Angiography is the imaging technique used to visualize the vascular system and the blood supply of some organs, which combines traditional radiology methods and modern computing techniques.  It is done by injecting a contrast agent into the blood vessel. Examinations may be targeted at the arterial system (for example to visualize stenosis in the lower limbs, kidneys, heart, or cerebral arteries) or the venous system. To look at the arterial system, access to the blood vessels is gained through an artery, whereas to look at the venous system, a vein is used. There is usually no need for sedatives, only a local anesthetic is used before the examination which should not cause more pain than a blood draw. In most cases access to the vessels is gained in the groin as the femoral artery and vein in the inguinal region are located close to the surface which makes puncture easier and also the procedure easy to control. After local anesthesia a catheter, that is a thin, flexible tube, is inserted into the vessel. The catheter is carefully guided to the organ being examined (such as the heart, kidney or brain), then contrast agent (a special dye) is injected to visualize the condition of the vessels in the area or the blood supply of the organ being examined.  Right after the injection of the contrast agent, often in a few minutes, patients may feel warm and flushed but this reverses spontaneously - something the patient is always informed about beforehand. After the procedure the catheter is removed, and if the intervention had been done through an artery, pressure is placed on the cut to stop any bleeding.  The most common - but usually not serious - side effect is the formation of a swelling of blood (hematoma) at the site of the insertion.  To prevent it, patients should lie still after the examination. The risk of developing hematomas is much more increased in patients with different coagulation disorders.  In such cases consideration should be given whether to have the examination at all or to have it at a later time after the normalization of coagulation values.  More serious side effects like vessel rupture (dissection) or clot formation due to the intervention are very rare and can generally be treated immediately on spot.  If needed, treatment may be done at the same time; this is known as angioplasty. During this procedure the abnormally narrowed vessel segment is dilated with the help of some special procedures (special catheters). Compared to surgery, this intervention is much less risky and demanding for patients; however, it cannot be performed in all cases (it depends on the site and the type of the abnormality).