Transluminal ballooning is a procedure that opens blood vessels, allowing blood flow and oxygen to get to the brain more easily. Researchers believe that this dilation of the blood vessels lasts for at least 7 days. This procedure is used to treat severe vasospasm although it is not commonly used to prevent vasospasm. The purpose of this trial is to find out if this procedure, performed immediately after the aneurysm is secured, prevents spasm in the brain and improves patient outcome.