The role of plasma lipids in carotid bifurcation atherosclerosis

276

128

We related risk factors, cardiovascular symptoms, and coronary status to the extent of extracranial carotid atherosclerosis as measured by B-mode ultrasonography in 376 volunteers hospitalized for elective coronary angiography. In a first analysis, we correlated risk factors and cardiovascular symptoms with carotid atherosclerosis. Univariate analysis showed that relations between many continuous risk factors and carotid atherosclerosis were graded and consistent for men and women. Multivariate analysis identified 6 significant variables (age, hypertension, pack-years smoked, and inversely, plasma concentrations of high density lipoprotein cholesterol and uric acid, and Framingham Type A score) that together accounted for 35% of the variability in extent of carotid atherosclerosis. In a second multivariate analysis, addition of coronary status (presence or absence of coronary stenosis as evaluated by coronary angiography) to the roster of candidate independent variables produced a new equation that accounted for an additional 5% of the variability in carotid atherosclerosis extent. Although much of the variability in extent of carotid atherosclerosis remains unexplained, these data define an association between coronary and carotid atherosclerosis that depends partly on shared exposure of both arteries to the same risk factors. They are also consistent with the concept that as yet undiscovered risk factors and/or genetic (e.g., arterial wall) factors common to both arterial beds also contribute to the relation between coronary and carotid atherosclerosis in human beings. (Stroke 1987; 18:990-996) T he relation between extracranial carotid atherosclerosis and transient ischemic attacks (TIAs) and cerebral infarction is similar to that between coronary atherosclerosis and angina pectoris, myocardial infarction, and sudden death. The extent to which investigators express interest in risk factors for coronary atherosclerosis is reflected by 200 citations referenced in a 1983 review.1 In contrast, relatively few publications have related risk factors to atherosclerosis of the intracranial and/or extracranial arterial system. 2~23 Approximately one third of these are autopsy studies, 18 " 23 and the remaining two thirds are studies of living people.In all studies, age is the most important risk factor for carotid atherosclerosis; sex may also be important.

Section: O -21supporting

confidence: 89%

Risk factors for extracranial carotid artery atherosclerosis.

Crouse

Toole

McKinney

et al. 1987

276

128

“…20,21 IMT was found to correlate with LDL-C and triglyceride and to correlate inversely with HDL-C. 13 In the fasting state, LDL-C, but not HDL-C and plasma triglycerides, was related to IMT in 50-year-old white men. 22 Lp(a) was also suggested as a risk factor for carotid atherosclerosis.…”

Section: Potential Role Of Lipoprotein Metabolism In Carotid Atheroscmentioning

confidence: 96%

Early-Onset Carotid Atherosclerosis Is Associated With Increased Intima-Media Thickness and Elevated Serum Levels of Inflammatory Markers

Magyar

Szikszai

Balla

et al. 2003

131

Background and Purpose-Several factors have been held responsible for the development of atherosclerosis. To avoid the masking effect of age, we evaluated correlates of carotid atherosclerosis in patients Ͻ55 years of age. Methods-Plasma lipids, oxidative resistance of low-density lipoprotein, homocysteine, inflammatory markers, plasma viscosity, and red cell deformability were measured in fasting blood samples of 100 subjects: 45 patients with Ͼ30% stenosis of the internal carotid artery, 20 patients with carotid occlusion, and 35 control subjects. Stenosis and intima-media thickness (IMT) of the carotid artery were evaluated by duplex ultrasound. Results-White blood cell (WBC) count, plasma fibrinogen, C-reactive protein (CRP), and lipoprotein(a) levels were significantly higher in patients than in control subjects, and patients had increased IMT (PϽ0.01 for all comparisons). There was a tendency for higher homocysteine levels in patients. Smokers had higher WBC, fibrinogen, and CRP levels. After the effect of smoking was controlled for, WBC count, natural logarithmic transform of homocysteine, and online-measured IMT remained significantly higher in patients than in control subjects. WBC, fibrinogen, and CRP levels were highest in the highest IMT quartile (Pϭ0.012, Pϭ0.007, and Pϭ0.036, respectively). Conclusions-Inflammatory markers and homocysteine have a more important role than lipid factors in early-onset carotid atherosclerosis. We cannot recommend the measurement of low-density lipoprotein peroxidation as a routine screening test to identify high-risk patients for early-onset carotid atherosclerosis. The confounding effect of smoking on inflammatory markers should be considered in studies on atherosclerosis.

“…15 ' 16 One study 15 found that the average stenosis of the two internal carotid arteries was correlated with age, total cholesterol concentration, the high density lipoprotein cholesterol: total cholesterol ratio, history of smoking, and hypertension; however, that study assessed the variables individually, with no adjustment for the confounding effects of any variables other than age. The Italian Multicenter Study 16 included only patients with symptomatic cerebrovascular disease, and the authors found that history of cigarette smoking, age, and cholesterol level were related to the presence of extracranial CAS; however, only cigarette smoking was related to the severity of extracranial CAS.…”

Section: Discussionmentioning

confidence: 99%

Duration of cigarette smoking is the strongest predictor of severe extracranial carotid artery atherosclerosis.

Whisnant

Homer

Ingall

et al. 1990

137

The effect of cigarette smoking on extracranial carotid atherosclerosis was studied by obtaining cigarette smoking histories and information on other potential risk factors from consecutive patients undergoing carotid arteriography. At least one extracranial carotid artery was visualized in 752 patients in whom the extent of carotid atherosclerosis was assessed. The total years of cigarette smoking was the most significant independent predictor of the presence of severe carotid atherosclerosis. Other independent predictors, in order of significance, were age, hypertension, diabetes mellitus, male sex, and current systolic blood pressure. By age 60 years, the risk of having severe carotid atherosclerosis for a person who had smoked for 40 years was approximately 3.5 times that for a never smoker. The major benefit of smoking cessation is in limiting the accumulation of smoking years. (Stroke 1990;21:707-714)