MRI Used to Monitor Cholesterol Drugs

Magnetic resonance imaging (MRI) scanning could become an important new tool fo revaluating how well cholesterol drugs are working.

Loyola University Health System (Maywood, IL, USA) cardiologist Binh An P. Phan, MD, coauthor of an MRI study of patients who had recently begun taking cholesterol medications, found that intensive treatment with cholesterol drugs significantly reduced the amount of cholesterol in artery-clogging plaque.

The study’s findings were published in the September 2011 issue of the JACC (Journal of the American College of Cardiology) Cardiovascular Imaging. Imaging technologies conventionally used to monitor cardiovascular disease, such as angiograms and ultrasounds, show the overall size of the plaque buildup. In the new study, MRI scans were more exact, showing the amount of cholesterol within the plaque.

The study was conducted at the University of Washington (Seattle, WA, USA), where Dr. Phan completed a cardiovascular clinical and research fellowship. The study included 120 patients who were randomly assigned to receive one of three cholesterol treatments: Lipitor; Lipitor plus Niaspan (extended-release niacin); or Lipitor plus Niaspan and colesevelam.

After three years, the 33 patients with identified carotid plaques had a considerable reduction in the cholesterol within the plaque. The volume of cholesterol decreased from 60.4 cubic mm2 to 37.4 mm2, and the percentage of plaque volume consisting of cholesterol decreased from 14.2% to 7.4%.

The scans were conducted on patients’ carotid arteries in the neck, instead of on their coronary arteries. Carotid arteries are easier for capturing images of because they are closer to the surface of the body and do not move as much as coronary arteries of a beating heart. Because atherosclerosis occurs in blood vessels throughout the body, plaque buildup in carotid arteries is a good representation of what is occurring in coronary arteries.

The study’s findings confirmed the researchers’ theory that the reason why cholesterol medications shrink the overall size of the plaque is because cholesterol is being removed from within the plaque. Therefore, using MRI scans to track the amount of cholesterol in plaque may help doctors to better determine how well cholesterol medications are working. If an MRI revealed that cholesterol was not being reduced, more aggressive therapy might be needed, according to Dr. Phan.

“In the future, MRI scans may become important and powerful tools to see how medication therapy is working inside arteries,” Dr. Phan concluded. “However, our study is just the first step. Additional studies will be needed.”

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Loyola University Health System
University of Washington