"Aggressive lipid (fat) lowering may become part of our armamentarium for the treatment of ischemic coronary syndromes," reports Charles B. Treasure, assistant professor of medicine (cardiology) at the School of Medicine. "In addition, clinical assessment of endothelial tone regulation may become a starting point for directing preventive approaches and an endpoint for evaluation of therapeutic efficacy in coronary atherosclerosis."
Not only do blood vessels in patients with coronary artery disease get dangerously clogged with plaque, impeding blood flow, vessels also get out of shape and become more prone to tightening than relaxing. This increased coronary tone is associated with high cholesterol levels and coronary atherosclerosis, and may further obstruct blood flow in the artery. The endothelium, the single layer of cells that line the inner arterial wall, is responsible for maintaining vascular tone.
The group studied 23 patients with established coronary artery disease for six months. All subjects were asked to follow the American Heart Association Step 1 lipid-lowering diet. Twelve patients were randomized to take the drug lovastatin, and 11 took placebo pills. At six months, the arteries of the lovastatin-treated group narrowed an average of only 1 percent, compared to 14 percent for the control group.
When comparing the most constricting segments of each patient, the researchers found after six months that even the most contracted arteries of the lovastatin-treated group constricted only 4 percent, compared to an average of 19 percent constriction among the control group.
Lovastatin is a member of the class of cholesterol-lowering agents known as HMG CoA reductase inhibitors.
"It is possible that improved endothelial function will be associated with diminished symptoms and clinical events in patients with coronary atherosclerosis," the authors report. "If so, these observations may have considerable impact on our future management of this disease. Treatment strategies would focus on converting active, potentially unstable atherosclerotic lesions (plaque) to quiescent, stable lesions with little potential for causing devastating clinical events. An ability to improve vascular function and stabilize atherosclerotic plaques combined with a reliable, inexpensive means to detect this effect could potentially avert, for many patients, the need for costly surgical or catheter-based therapies," the authors report.
Other Emory cardiology collaborators on the paper include: R. Wayne Alexander, professor and division director; William S. Weintraub, professor; J. Larry Klein, assistant professor; and Jian Zhang, research project coordinator. Andrzej S. Kosinski of the Division of Biostatistics in the Rollins School of Public Health also collaborated on the study.
-- Lorri Preston