Findings from one of the largest medical studies in history, published this month in the American Journal of Cardiology, provide clear evidence that the cholesterol-lowering medicine Zocor(R) (simvastatin) lowers the risk of cerebrovascular events in people with coronary heart disease by more than a quarter.
Entitled "Effect of Simvastatin on Ischemic Signs and Symptoms in the Scandinavian Simvastatin Survival Study (4S)", it is the first intervention trial to ever demonstrate a direct link between cholesterol-reduction and stroke prevention.
Stroke is Canada''s third leading cause of death and the leading cause of disability. It kills more than 15,000 Canadians each year, and represents approximately $2.5 billion CDN in annual direct health expenditures. Ischemic strokes, responsible for three quarters of all strokes, occur when a blood clot blocks the flow of blood to the brain. Established drugs used to help prevent stroke (most frequently antiplatelet agents such as aspirin) seek to halt the formation of blood clots and to prevent vascular occlusions.
Although researchers have already proven cholesterol-reduction with Zocor leads to significant reduction in heart attack, it has only now been definitively demonstrated that positive benefits can be achieved in stroke prevention.
"Today''s news is extremely important for Canadians at risk for stroke," said Dr. Marc-André Lavoie, chief of internal medicine, Montreal Heart Institute. "The stroke prevention tool box physicians have traditionally turned to has been limited. Antiplatelet agents are frequently accompanied by side effects which limit their use.
"Reducing the risk of stroke by lowering cholesterol with Zocor represents an extremely promising new treatment strategy and one which is associated with very minor side effects."
The study included 4,444 men and women between 35 and 70 years of age. Each had coronary heart disease (history of heart attack or angina) and moderately elevated cholesterol levels. Patients received daily doses of either 20 mg or 40 mg of Zocor.
As reported this month in the American Journal of Cardiology, Zocor patients in the trial experienced:
-- 28 per cent risk reduction of cerebrovascular events
-- 28 per cent risk reduction of transient ischemic attacks (TIA) or mini-strokes, considered warning signs of imminent full-blown stroke
-- 48 per cent reduction in the development of carotid bruit (a narrowing of the blood vessel in the neck)
"These results clearly indicate that Zocor has a valuable role in preventing strokes and their horrific consequences," stated Dr. Jacques Genest Jr., director of the Cardiovascular Genetics Laboratory at the Clinical Research Institute of Montréal and Staff Cardiologist at the Centre hospitalier de l''Université de Montréal.
Stroke accounts for seven per cent of all deaths in Canada. According to recent Heart and Stroke Foundation statistics, stroke accounted for 88 deaths per 100,000 people in Quebec in 1995.
Stroke is characterized as damage occurring in the brain when blood flow is interrupted by either a blocked or burst artery. This interruption deprives the brain of oxygen causing brain cells to die. Hemorrhagic stroke, usually associated with high blood pressure, occurs when blood vessels in the brain rupture and damage surrounding tissue.
Symptoms of a stroke, such as weakness or paralysis on one side of the body can develop abruptly or gradually. Approximately one-third of major strokes are fatal, a third result in some disability and a third have no lasting ill effects. Risk factors for stroke include hypertension, smoking, alcohol, diet and lack of exercise.
Zocor was approved in Canada in August, 1990. In May, 1996, the product became the first and still is the only medication in its class to receive special Health Canada designation as a life-saving medicine.
Zocor is used in combination with diet to reduce cholesterol levels in patients with primary hypercholesterolemia when diet alone has not been successful.