September 28, 2010

Operating On Neck May Reduce Long Term Stroke Risk

(Ivanhoe Newswire) -- Surgeons are narrowing the outcome of stroke for at least 10 years by safely operating on narrowed neck arteries.  The downside of operating on the main arteries that take blood to the brain is the 3 percent risk of immediate stroke.  But does this immediate risk outweigh the long-term benefits?

Among men and women under 75 years of age who are in good health -- with the exception of a narrowed neck artery -- there are likely to be substantial benefits from operating, as long as the surgical risks remain low.

In a randomized trial, Professor Alison Halliday and Professor Sir Richard Peto of the University of Oxford, UK, in addition to their international collaborators from 30 countries, assessed the long-term effects of successful CEA in patients with carotid artery narrowing that has remained asymptomatic, and has furthermore been detected via ultrasound or any other method of scanning.

The study (ACST-1) involved 3120 patients with narrowed carotid arteries, where the doctors and patients alike were uncertain whether or not to go through with surgery.  The researchers randomly allocated half of the patients to have immediate CEA and the other half to have indefinite deferral of a carotid procedure until there arose a more definite need.   Ultimately, several of the allocated deferrals were operated on, and some patients eventually had the artery on the opposite side of their neck operated on as well. A total of 1979 CEA's were done during the study.  Among them, the perioperative risk of stroke or death within 30 days was 3.0 percent (this included 26 non-disabling strokes plus 34 disabling or fatal events.

The median follow-up for the study was 9 years.  Excluding perioperative events, the immediate vs. deferred CEA was 4.1 percent vs. 10.0 percent at 5 years and 10.8 vs. 16.9 percent at 10 years.  The net risks (combing both the perioperative events in addition to strokes) was 6.9 percent vs. 10.9 percent at 5 years and 13.4 percent vs. 17.0 percent at 10 years.  Medical treatment included a combination of antiplatelet, antihypertensive, and lipid-lowering drugs which considerably reduced risk of stroke (used widely in both the immediate CEA and deferral groups).  Throughout the study, most patients were on antithrombotic and antihypertensive therapy although routine use of statin therapy rose precipitously from below 10 percent -- when the study commenced in the mid 1990's -- to an astonishing 80 percent in recent years.  There was net benefit from immediate CEA whether or not statins were being used, along with net benefits for both men and women up to 75 years of age at entry (although not for older patients).

Cartoid artery lesions generally involve indistinguishable sorts of fatty deposits that coronary artery lesions do.  Although, as the left and right carotid arteries provide the main blood supply to the brain, carotid lesions can cause a detrimental or permanently disabling stroke.  "This trial took more than 15 years to complete, because we wanted to know about the long-term effect of surgery," according to Professor Halliday.  "The finding that successful carotid artery surgery can substantially reduce the stroke risk for many years is remarkable because it means that most of the risk of stroke over the next 5 years in patients with a narrowed cartoid artery is caused by that single carotid lesion.  The definite benefits that we have found will be of practical value to doctors and patients deciding the future whether to take the immediate risk of having the surgery.  An alternative to carotid artery surgery is inserting a stent into a narrowed carotid artery to hold it open.  If patients have not yet had a stroke, both carotid surgery and carotid stenting cause an immediate stroke risk of about 3 percent.  Our next trial (ACST-3) is comparing their long-term protective effects, but its final results will take at least another decade to emerge."

SOURCE: The Lancet