DALLAS – Regression of coronary atheroma load was linked with cuts in systolic blood pressure and pulse pressure in an analysis of data from 274 patients.
Patients whose average systolic pressure fell below 120 mm Hg or those whose pulse pressure dropped below about 46 mm Hg had a significant regression in their coronary atheroma load during 2 years of follow-up, Dr. Ilke Sipahi reported at the annual Scientific Sessions of the American Heart Association. Among patients whose average pressures were above these levels, higher pressure was directly associated with increased atheroma load during follow-up, said Dr. Sipahi, a cardiologist at the Cleveland Clinic Foundation.
“Hypertension is involved in initiating atheroma by damaging endothelial cells and making them more permeable to lipids,” explained Dr. Steven E. Nissen, medical director of the Cleveland Clinic Cardiovascular Coordinating Center and a coinvestigator on the study. “In blood vessels there's a battle between the forces that drive oxidized cholesterol into vessel walls and the forces that are trying to pull it out. Everyone focuses on lipids, but we need to think more about blood pressure.”
The analysis used data collected in the CAMELOT study, which compared the ability of amlodipine or enalapril with placebo to prevent cardiovascular events in patients with coronary artery disease and hypertension (JAMA 2004;292:2217-25). The primary finding of the CAMELOTstudy was that amlodipine was more effective than enalapril for preventing cardiovascular events.
In a substudy, 274 patients who required coronary angiography for clinical indications underwent intravascular ultrasound assessment at baseline and 24 months later. Atheroma burden in a representative segment of the coronary artery of each patient was calculated by summing the atheroma areas in a series of cross-sectional ultrasound images taken at 1-mm intervals. Blood pressures were measured in each patient at 3-month intervals, and each patient's average pressures during follow-up were used for this analysis.
In a multivariate analysis that controlled for several clinical and demographic variables, including the ratio of total cholesterol to HDL cholesterol and atheroma burden at baseline, systolic blood pressure and pulse pressure were the only variables that were significantly associated with changes in atheroma burden, Dr. Sipahi said.
“The relationship between systolic blood pressure and pulse pressure and atheroma volume was independent of the treatment that patients received, and was independent of their lipid levels,” he said. The analysis showed no link between changes in diastolic pressure and changes in atheroma volume.