Etiologic factors in progression of carotid stenosis: A 10-year study in 905 patients

Purpose: The purpose of this study was to determine the etiologic factors i n the progression of carotid stenosis. Methods: We performed prospective serial duplex scan surveillance of 1470 c arotid arteries in 905 asymptomatic patients during a 10-year period, with an average follow-up interval of 29 months and an average of 3.0 scans per carotid artery. Vascular laboratory and hospital records were used to colle ct risk factor information. The data were analyzed with proportional hazard s modeling. Results: We examined several demographic, clinical, and laboratory risk fac tors that were chosen because of their potential relevance to atherosclerot ic disease. These factors were analyzed with univariate proportional hazard s modeling, in which time to progression of stenosis was the outcome variab le. The six significant predictors (P < .05) were age, sex, systolic pressu re, pulse pressure (systolic pressure - diastolic pressure), total choleste rol, and high-density lipoprotein (HDL). All, except HDL, were positive pre dictors of time to disease progression. With multivariate modeling, only pu lse pressure and HDL remained as significant independent predictors of sten osis progression. The risk ratio for a 10-mm Hg rise in pulse pressure was 1.12, and the risk ratio for a 10-mg/dL decrease in HDL was 1.20. Conclusion: In this large cohort of patients who were followed prospectivel y for carotid stenosis, pulse pressure and HDL were found to be the key ris k factors for carotid stenosis progression. The fact that pulse pressure su perseded systolic pressure in multivariate modeling may shed light on the b iology of carotid plaque progression. Further, our identification of these modifiable risk factors may help in the design of therapeutic trials for th e prevention of progression of carotid atherosclerosis.