Stroke

Description

Alternative Names

Surgery

Carotid endarterectomy is a surgical procedure used to clean out and open up the narrowed carotid artery. It is used in patients at high risk for thrombotic ischemic strokes, which are caused by blockage in the internal carotid artery. It is also sometimes used after a stroke in certain patients. In such cases, patients have reported improvements in vision, speech, swallowing, functioning of arms and legs, and general quality of life. The studies showing such high benefits of surgery versus drug therapy were done in institutions whose surgeons are experienced with such operations.

Anyone undergoing this procedure should be sure their surgeon is experienced in recent techniques and that the medical center has complication rates of less than 3%. A 2000 study reported that older surgeons had a worse record than younger ones, possibly because they relied on residents or were less likely to adopt new procedures.

Procedure Description. The procedure generally is as follows:

• The patient is usually given general anesthesia, although it has been reported that using local anesthetic is just as safe and reduces the cost of the procedure.
• A by-pass tube is put in place to transport blood around the blocked area during the procedure.
• The surgeon scrapes away the plaque on the arterial wall.
• The artery is sewn back together and blood flow is restored.
• The patient generally stays in the hospital for about two days. There is often a slight aching in the neck for about two weeks, and the patient should refrain as much as possible from turning the head during this period.

Patients who have this procedure after a stroke are usually advised to wait six weeks. Studies are reporting, however, that having the procedure earlier does not pose greater risks.

Endarterectomy is a surgical procedure removing plaque material from the lining of an artery.

Click the icon to see an illustrated series detailing surgery for unblocking carotid arteries.

Determining Who Should Have Surgery. Evidence strongly suggests that most patients with severe stenosis (over 70% of the carotid artery is obstructed) can benefit from endarterectomy. And, it is also clear that patients with mild stenosis (less than 50% obstruction) would do better with medications--even if they have symptoms.

The benefits of endarterectomy for people with stenosis between 50% to 70% are not clear, however. The best candidates for preventive carotid endarterectomy in such cases may be those that meet all of the following conditions:

• They have symptoms that indicate blockage in the brain.
• They are male. The benefits of this procedure for women are uncertain.
• They have a history of a stroke that occurred three months earlier or less.
• They have access to a medical center in which major complications rates after endarterectomy are less than 3%.

Significant controversy surrounds the treatment of patients who have severe stenosis but who do not have symptoms. A 1995 study estimated that endarterectomy in such patients would reduce the risk for stroke from 11% to 5%. However, these patients were treated in medical centers with highly skilled staff and less experienced centers have reported higher complications and lower success rates. A 2002 study suggested that, in any case, asymptomatic patients even with blockages of well over 50% actually have a low risk for a stroke. In this small study, such patients had only a 9.3% risk for a stroke at 10 years and a 15% risk at 15. Furthermore, an important 2000 study found that only 3.5% of the strokes that occurred in such patients were due to blockage in the carotid arteries--the only condition that is benefited by carotid endarterectomy. Over half of the strokes in that study were caused by embolisms (traveling clots) or lacunar infarcts (very tiny, ischemic strokes). Some experts still believe that many asymptomatic patients are good candidates for the procedure. However, to be beneficial, the procedures should be performed only in experienced medical centers.

Complications. There is a risk of a heart attack or even stroke from the procedure. Studies have reported, in fact, that strokes occur during or immediately after the operation in up to 9% of these operations. The other overall risk of death from postoperative stroke was 2.8%. Women appear to have a significantly higher risk for postoperative stroke than men have.

Carotid Angioplasty and Stenting

Carotid angioplasty is being investigated as an alternative to carotid endarterectomy. It is based on the same principles as angiography done for heart disease.

• An extremely thin catheter tube is inserted into an artery in the groin.
• It is threaded through the circulatory system until it reaches the blocked area in the brain carotid artery.
• The physician either breaks up the clot or inflates a tiny balloon against the blood vessel walls (angioplasty).
• After temporarily inflating the balloon, the doctor typically leaves a circular wire mesh (stent) inside the vessel to keep it open.

This procedure carries a risk for an embolic stroke and other complications. At this time, it is being used in some centers as an alternative to endarterectomy in patients who cannot undergo endarterectomy. A 2002 study, however, from one center reported that complications from stents were equal to or even less than those of endarterectomy. The stent procedure is less costly than endarterectomy and some experts are hoping that it may eventually be performed more often than it is now.

Hemicraniectomy

Hemicraniectomy is surgical removal of a bone patch from the skull to relieve pressure. The bone is stored under sterile conditions and reimplanted a few months latter. It may have be a life-saving option for some patients with severe stroke that has resulted in swelling and injury to a large area in the brain. Studies are showing some benefits for high-risk patients, but more information is needed to determine specific conditions that will respond to this treatment. (In one study, for example, patients with subarachnoid hemorrhage had a poor outlook after this procedure.)

Extracranial-Intracranial Bypass

Extracranial-intracranial (EC-IC) bypass has been under investigation for decades for ischemic stroke, but has had very mixed results, some extremely negative. With this procedure a healthy artery in the scalp is rerouted to an area of the brain that was deprived of blood because of a blocked artery. This procedure is now sometimes used for patients with aneurysms. Some experts hope, however, that, in specific cases chosen via careful imaging and using the latest surgical techniques, EC-IC may prove to be helpful for some stroke patients.

Surgery for Preventing and Treating Hemorrhagic Strokes

Surgical Intervention of the Ruptured Aneurysms. In patients with subarachnoid hemorrhagic stroke, surgery to block off the aneurysm is usually recommended within a few days of the stroke. The standard procedure is to clip the aneurysm and stop bleeding. Alternative approaches are promising.

Surgical Intervention of Unruptured Aneurysms. If an unruptured aneurysm is detected, patients should discuss all options with their physician, including surgical repair. Unruptured aneurysms occur in between 1% and 8% of the general population, however, and controversy exists over when to operate and on which patients.

In general, the decision rests on the size of the aneurysm, but uncertainty still exists. For aneurysms between 10 and 25 mm, for example, in one study the risk of rupture was quite low --slightly less than 1% per year for both groups. Aneurysms over 25 mm, however, had a 6% chance of rupturing within a year. Studies have reported that in general, the risk for rupture is between .05% to 2% a year, but recent evidence suggests that the risks may be even less. In one study, even people with a history of subarachnoid hemorrhage had only a 0.5% annual risk for recurrence when aneurysms were small.

Aneurysms can often cause symptoms, however, even if they do not rupture. Patients should discuss their particular risk factors carefully with their physicians. Individuals with arteriovenous malformation, a condition caused by abnormal associations between arteries and veins, should be monitored for the development of aneurysm.

Clipping the Aneurysm. The standard surgical procedure for treating a ruptured aneurysm is to place a clip across the neck of the aneurysm, which blocks off bleeding. It is usually performed within the first three days. Getting to the aneurysm is often extremely difficult. Deep cooling of the body to stop circulation may be used to allow more time for the operation. Procedures that remove large portions of the bone in the skull are being developed to allow fast access. There is a relatively high risk for newly formed aneurysms, particularly after nine years. Patients may want to discuss follow-up angiography to detect any new aneurysms nine or ten years after the procedure.

Transcatheter Embolization for Sealing off the Aneurysm. Transcatheter embolization is a new technique for ruptured and unruptured aneurysms that is proving to be effective although is still investigative. The surgeon threads a thin tube through the artery leading to the aneurysm through which materials are passed to plug or obstruct the aneurysm. In one version of this procedure, the following occurs:

• A tiny platinum coil is inserted through the tube and positioned into the aneurysm.
• An electric charge is passed through the coil to form blood clots.
• In this case, blood clots benefit the patient by using the coil as a scaffold and sealing off the aneurysm.

A 2002 study suggested it could be attempted safely in over 95% of patients with unruptured aneurysms. In the study, the procedure eliminated the aneurysm in nearly 90% of the patients. In small trials using the coil with a ruptured aneurysm, only 3.7% of patients suffered a second stroke after seven months compared to the usual re-rupture rate of 30% to 40%.

Emergency Surgery for Hemorrhagic Strokes. Emergency surgery for a hemorrhagic stroke usually involves locating and removing large blood clots. In the past, such procedures had little effect on survival. Advances, however, are improving outcome when surgery is performed very early.