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.