Treatment for a subarachnoid hemorrhage requires emergency medical assistance and ideally takes place in an intensive care unit. Once patients are admitted to the hospital, physicians will first attempt to correctly diagnose the event, stabilize the patient and locate the hemorrhage. During this time, preventing rebleeding and cerebral infarction (death of brain tissue due to lack of oxygen) are primary considerations, along with preventing vasospasm of the arteries. Vasospasm typically occurs no earlier than day three after the original event, and it is a major source of death and disability. In this early stage of treatment, a number of drugs might be used to prevent vasospasm, normalize blood pressure and reduce the risk of blood clots forming in the brain.

Whenever it is feasible, the patient will undergo surgery. The timing of surgery depends on complicated factors, including the risk of rebleeding and vasospasm versus the presence of swelling in the brain in the days immediately after the surgery. In some cases, surgery may be delayed by 14 days. In other cases, early surgery is warranted.

The approach toward an unruptured aneurysm is dictated by the risk of eventual rupture, with an eye toward reducing the risk. Surgery is generally considered the treatment of choice for an unruptured cerebral aneurysm, but when to do surgery, and for whom, remain controversial. The many factors under consideration include the patient’s age, general health and history of any previous ruptures, as well as characteristics of the aneurysm itself, including its size, location and whether it is growing, bleeding or putting pressure on the brain.

The most common surgical approach to a cerebral aneurysm is to use a small clip to cut off the blood supply to the aneurysm. The blood vessel that feeds the aneurysm is located and the clip is placed at the base of aneurysm. Clipping has been shown to be very effective depending on the type, location and size of the aneurysm. Overall, patients who have their aneurysms completely clipped do not experience a recurrence of the aneurysm. In some patients, the entire artery may be clamped off (occluded) and a blood vessel graft is used to reroute the blood flow around the damaged area.

Before surgery, the patient’s head will be shaved over the area of the aneurysm, and he or she will be given a sleep-inducing medication (general anesthesia). Then the surgeon will carefully cut open a small section of the skull, exposing the aneurysm. The surgeon will repair the aneurysm with the most appropriate procedure for the patient's condition.

An alternative to surgery is embolization. During this procedure, a thin, hollow tube catheter is inserted through an artery (usually in the groin or wrist) up to the site of the aneurysm. Once the catheter reaches the aneurysm, tiny balloons or coils inserted into the aneurysm. These devices block the blood from circulating in the aneurysm, causing the blood to clot. When the blood clots, it essentially destroys the aneurysm. Patients may need to undergo emobolization more than once in their lifetime.

If balloons are used, the procedure is also called balloon embolization. If the coils are used, the procedure is also called microcoil thrombosis. Though this technique is not used as often as clipping, it is less invasive and may offer an option for some aneurysm patients who are not candidates for surgery.

Because some cerebral aneurysms develop as a result of heart defects or other conditions that cannot be prevented, there are no specific prevention strategies for cerebral aneurysms. People who want to reduce their risk of suffering a ruptured cerebral aneurysm are encouraged to control their blood pressure, avoid or quit smoking and avoid heavy alcohol use. Physicians may also provide recommendations regarding medications (e.g. taking aspirin, discontinuing oral contraceptives).

Researchers continue to study various factors that can help determine which unruptured aneurysms should be surgically repaired. The findings of one large study suggested that aneurysms less than 7 millimeters (slightly smaller than a half an inch) have a low probability of rupture. Scientists examined vascular defects that also may contribute to the risk of rupture.

Researchers are currently working on additional strategies to treat and detect aneurysms. These strategies include a new drug, called proliNO, which may help treat cerebral vasospasms after an aneurysm rupture. They are also studying antibodies to molecules that promote vasospasm.

Additional research for the treatment of cerebral aneurysms includes:

• Less invasive, high resolution x-rays that can help physicians use stents (mesh-like tubes) to widen the artery and restore blood flow.
  
  
• Balloon angioplasty following a ruptured aneurysm to destroy the clot and control blood flow in the artery.
  
  
• Hypothermia during surgery to reduce the risk of postoperative complications and neurological damage.
  
  
• New coils for embolization treatment as well as improved techniques for replacing the coils.
  
  
• New methods for evaluating tissue for response to devices used in surgical repair of an aneurysm.
  
  
• Computer simulation model that assesses the outcomes of various surgical techniques in patients with cerebral aneurysms.

To evaluate risk factors for cerebral aneurysms, several groups of researchers are studying genetics, family medical histories and ethnic backgrounds for patterns of inheritance. They are examining the use of blood and tissue sampling for genetic linkage and molecular analysis. Other studies are focusing on prevention and treatment strategies for individuals who are at high risk for developing aneurysms based on genetic factors.