Calcium-Blocker Drug Slows Artery Clogging Better Than Beta Blocker

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The study tested two high blood pressure medications: lacidipine, a calcium channel blocker, and atenolol, a beta blocker. Beta blockers reduce the heart's tendency to beat faster as it tries to compensate for weakened pumping ability. Allowing the heart to maintain a slower rate lowers blood pressure. Calcium channel blockers interfere with calcium's role in the contraction of these muscles. This causes the muscles to relax, lowering blood pressure and improving blood circulation in the heart.

Ultrasound images taken at the start of the study revealed that patients had measurable atherosclerosis in the carotid arteries. After four years of treatment, the yearly progression rate for this narrowing was 40 percent lower in lacidipine-treated patients than in the patients treated with atenolol.

Researchers tracked plaque progression by measuring intima-media thickness (IMT) in participants' carotid arteries, which carry blood to the brain. IMT is a measurement of the interior lining of blood vessels. During the four-year study, researchers found that people taking atenolol showed an increase in IMT by 0.0145 millimeters per year (mm/yr), while IMT in people taking lacidipine increased by 0.0087 mm/yr.

Alberto Zanchetti, M.D., lead researcher of the European Lacidipine Study on Atherosclerosis (ELSA), says this difference was apparent even though average ambulatory blood pressure reduction among patients taking lacidipine was less than the average reduction achieved by patients taking atenolol.

Zanchetti, who is a professor of medicine at the University of Milan and scientific director of Istituto Auxologico Italiano in Milan, says the finding suggests "it is some specific property of the calcium antagonist we have used in addition to the lowering of blood pressure, that slows down the progression of atherosclerosis."

Calcium channel blockers, also called calcium antagonists, decrease the rate at which calcium flows into the heart and blood vessel walls. This, says Zanchetti, appears to have the beneficial effect of slowing the growth of cells that line the blood vessels and arteries and reducing the size of plaques, the fat deposits that accumulate in arteries.