Balloon Arterial Occlusion Test
A balloon arterial occlusion test is performed to determine whether a patient could live without any problem if one carotid artery is sacrificed during surgery. This test is particularly important in cases of tumor invasion around one of the carotid arteries or in situations when there is a vascular malformation or giant aneurysm. Since an occlusion or blockage of the artery can be part of the strategic approach for the treatment of the condition, it is extremely important for the surgeon to know if the patient could live without any symptoms after the artery is occluded. This information is also crucial when removing tumor from the walls of a carotid artery invaded by tumor. If a rupture occurs the surgeon can safely decide in closing the carotid artery without any consequences for the patient.
Occluding a cerebral artery may be considered in treating an aneurysm or in the treatment of a tumor that is closely linked to the artery. There are four arteries that supply blood to the brain;the carotid arteries travel up the front of the neck and the vertebral arteries travel up the back of the neck. If one artery is blocked, connections between the arteries, called collaterals, can allow the other arteries to continue supplying blood to the area of the brain usually supplied by the blocked artery. However, some people do not have a sufficient network of these connections, and therefore blocking one of the four main arteries would result in an ischemic stroke. The purpose of the balloon test is to establish the adequacy of the collateral arteries in an individual.
The procedure begins with the insertion of a catheter into the femoral artery via an incision in the groin area. The catheter has a tiny balloon on the end. It is threaded through the body to the cerebral artery under investigation, and then the balloon is gently inflated so as to block blood flow. In patients who have good connections, the other arteries are able to take over and there is no change in brain function. The balloon is left in place about 30 minutes. Those patients who do not have sufficient collaterals begin to show symptoms that part of their brain is not receiving enough blood, such as weakness or numbness on one side of the body, or difficulty speaking or understanding speech. In these cases the balloon is deflated immediately and removed. The symptoms go away as soon as the normal blood flow is restored.