Clues to Heart Attack, Stroke Risk From Fat-Filled Artery

MONDAY Aug. 30, 2010 -- A number of factors put patients with abnormal fatty deposits in an artery at high risk for heart attack, stroke and cardiovascular death, a new study shows.

Patients in various stages of this condition -- atherothrombosis -- are at increased risk for heart attack and stroke stemming from reduced blood flow from the artery blockage, but some are at greater risk than others. In an analysis of more than 45,000 patients, the researchers found that patients with abnormal fatty deposits in an artery were at highest risk if they had a prior history of heart attack or other emergencies linked to an artery blockage.

Narrowing of the arteries in various locations also substantially increased the risk for patients with atherothrombosis, as did diabetes for all the patients -- even those with only the risk factors for atherothrombosis.

Knowing that these factors boost the risk can help physicians take preventive action, according to the researchers, who are from the VA Boston Healthcare System, Brigham and Women's Hospital and Harvard Medical School in Boston.

The researchers analyzed data from 45,227 patients enrolled in an international study known as Reduction of Atherothrombosis for Continued Health (REACH) between 2003 and 2004. They collected detailed information from the patients when they enrolled and conducted follow-ups one, two, three and four years later.

They found that 81.3 percent of the patients had hypertension, 70.4 percent had high cholesterol levels in the blood, and 15.9 percent had polyvascular disease (narrowing of the arteries in numerous locations). In addition, 48.4 percent of the patients had "ischemic events" -- prior heart attacks, unstable angina or other problems related to the artery blockage, with 28.1 percent of those patients having had such an event within the previous year.

During the follow-up period, 2,315 patients suffered cardiovascular death, 1,228 had a heart attack, 1,898 had a stroke, and 40 had a heart attack and a stroke on the same day.

The researchers found that patients with atherothrombosis with a prior history of heart attacks and other events related to a blood vessel blockage had the highest rate of subsequent cardiac emergencies linked to blood flow problems. Patients with stable heart, cerebrovascular or peripheral artery disease had a lower risk, while the risk was lowest among those with risk factors for atherothrombosis but without established disease.

"Among all categories of patients, diabetes substantially increase the risk of future ischemic events," the study authors wrote. "In those with established atherothrombosis, polyvascular disease was a particularly strong independent risk factor, even stronger than diabetes."

The findings show that "there is a whole spectrum of [emergencies relating to artery blockage and blood flow] in patients with risk factors or with established cardiovascular disease -- easily ascertainable clinical characteristics are the prominent factors associated with a high risk of future ischemic events," they concluded.

The study appears online and in the Sept. 22 issue of the Journal of the American Medical Association and is slated to be presented Monday at the European Society of Cardiology meeting in Sweden.

More information

The U.S. National Heart, Lung, and Blood Institute has more about heart and vascular diseases.

Posted: August 2010


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