WASHINGTON (Reuters) - A modified magnetic scan can tell patients whether cholesterol-lowering statin drugs are actually unblocking their clogged arteries, U.S. researchers reported on Monday.

The magnetic resonance imaging (MRI) scans also can be used to settle arguments about how the drugs, which no one disputes work well to save lives, actually do it, the researchers, at Johns Hopkins University in Baltimore, said.

The MRI showed artery-blocking plaque thinning after six months of statin treatment, the team reported.

MRI has been used to monitor blocked arteries before but it typically took a year or more to show results. The Hopkins team improved their MRI's sensitivity by putting extra coil rings around the chest of each of the 29 patients in the study.

An antenna was inserted through the nose and down the esophagus of each patient to amplify the signal.

"Our study increases the likelihood that MRI could eventually be used as a predictive technology for determining which patients should be placed on statin therapy for atherosclerosis," said cardiologist Dr. Joao Lima, who led the study.

"While it has been proven that patients can benefit from even a short period of statin therapy, as early as 16 weeks, our abilities to harness modern technology for monitoring this condition -- and tracking the effectiveness of our treatments -- have not kept pace until now."

Statins work well but not for everyone, and some people may not think they are worth the side effects, which can include muscle pain or even damage in rare cases. The scans may show whether benefits outweigh risks early in treatment.

Statins can reduce plaque formation by as much as 40 percent, and death rates by 30 percent.

Writing in the American Heart Association's journal Circulation, the Hopkins team said it followed 29 patients who took Merck and Co's simvastatin, sold under the brand name Zocor, for three years.

They said their findings suggested the statins save lives because they take cholesterol out of the blood, not because of their secondary effects reducing inflammation.

They found that low-density lipoprotein (LDL) cholesterol -- the "bad" cholesterol -- was lowest in patients in whom plaque was reduced the most.

The American Heart Association says that atherosclerosis or clogged arteries accounts for nearly three-fourths of all deaths from cardiovascular disease.

SOURCE: Circulation, October 11, 2004.

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