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B-mode ultrasound common carotid artery intima-media thickness and external diameter: cross-sectional and longitudinal associations with carotid atherosclerosis in a large population sample.

Eigenbrodt ML, Bursac Z, Tracy RE, Mehta JL, Rose KM, Couper DJ - Cardiovasc Ultrasound (2008)

Bottom Line: Each standard deviation increment of baseline RCCA diameter was associated with increasing carotid lesion prevalence (unadjusted odds ratio [OR] = 1.54, 95% confidence interval [CI] = 1.47-1.62) and with progression of carotid atherosclerosis (unadjusted hazards ratio (HR) = 1.37, 95% CI = 1.28-1.46); and the associations remained significant even after adjustment for IMT and risk factors (prevalence OR = 1.11, 95% CI = 1.04-1.18; progression HR = 1.11, 95% CI = 1.03-1.19).Controlling for gender, age and race, persons with both RCCA IMT and diameter in the upper 50th percentiles had the greatest risk of progressing to clearly defined carotid atherosclerotic lesions (all HR = 1.71, 95% CI = 1.47-2.0; men HR = 1.88, 95% CI = 1.48-2.39; women HR = 1.59, 95% CI = 1.31-1.95) while RCCA IMT or diameter alone in the upper 50th percentile produced significantly lower estimated risks.RCCA IMT and external diameter provide partially overlapping information relating to carotid atherosclerotic lesions.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Epidemiology, Fay W, Boozman College of Public Health, University of Arkansas for Medical Sciences, Little Rock, AR, USA. meigenbrodt@sbcglobal.net

ABSTRACT

Background: Arterial diameter and intima-media thickness (IMT) enlargement may each be related to the atherosclerotic process. Their separate or combined enlargement may indicate different arterial phenotypes with different atherosclerosis risk.

Methods: We investigated cross-sectional (baseline 1987-89: n = 7956) and prospective (median follow-up = 5.9 years: n = 4845) associations between baseline right common carotid artery (RCCA) external diameter and IMT with existing and incident carotid atherosclerotic lesions detected by B-mode ultrasound in any right or left carotid segments. Logistic regression models (unadjusted, adjusted for IMT, or adjusted for IMT and risk factors) were used to relate baseline diameter to existing carotid lesions while comparably adjusted parametric survival models assessed baseline diameter associations with carotid atherosclerosis progression (incident carotid lesions). Four baseline arterial phenotypes were categorized as having 1) neither IMT nor diameter enlarged (reference), 2) isolated IMT thickening, 3) isolated diameter enlargement, and 4) enlargement of both IMT and diameter. The association between these phenotypes and progression to definitive carotid atherosclerotic lesions was assessed over the follow-up period.

Results: Each standard deviation increment of baseline RCCA diameter was associated with increasing carotid lesion prevalence (unadjusted odds ratio [OR] = 1.54, 95% confidence interval [CI] = 1.47-1.62) and with progression of carotid atherosclerosis (unadjusted hazards ratio (HR) = 1.37, 95% CI = 1.28-1.46); and the associations remained significant even after adjustment for IMT and risk factors (prevalence OR = 1.11, 95% CI = 1.04-1.18; progression HR = 1.11, 95% CI = 1.03-1.19). Controlling for gender, age and race, persons with both RCCA IMT and diameter in the upper 50th percentiles had the greatest risk of progressing to clearly defined carotid atherosclerotic lesions (all HR = 1.71, 95% CI = 1.47-2.0; men HR = 1.88, 95% CI = 1.48-2.39; women HR = 1.59, 95% CI = 1.31-1.95) while RCCA IMT or diameter alone in the upper 50th percentile produced significantly lower estimated risks.

Conclusion: RCCA IMT and external diameter provide partially overlapping information relating to carotid atherosclerotic lesions. More importantly, the RCCA phenotype of coexistent wall thickening with external diameter enlargement indicates higher atherosclerotic risk than isolated wall thickening or diameter enlargement.

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Related in: MedlinePlus

Representation of four arterial phenotypes based on enlargement of arterial wall thickness and external diameter. EEM = interface of media and adventitia. IMT = indicates normal intima-media thickness. L = interface of intima with lumen. Large bracket indicates normal external diameter.
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Figure 1: Representation of four arterial phenotypes based on enlargement of arterial wall thickness and external diameter. EEM = interface of media and adventitia. IMT = indicates normal intima-media thickness. L = interface of intima with lumen. Large bracket indicates normal external diameter.

Mentions: We also investigated the association of four arterial phenotypes at baseline with carotid atherosclerosis progression. The baseline arterial phenotypes consisted of isolated or concurrent enlargement of RCCA diameter and IMT or neither (See Figure 1). The 50th percentile value of each vascular parameter for men and women was used to classify persons as having an enlarged RCCA IMT (men: ≥0.66 mm; women: ≥0.61 mm) and/or diameter (men: ≥8.06 mm; women: ≥7.30 mm). To check the robustness of this approach, separate categorizations were based on the observed to expected ratio values for IMT and diameter. Expected IMT and diameter values were calculated for each participant based on gender-specific betas for age, race, and height determined from linear regression analyses performed on a subset of participants who were free of atherosclerotic-related conditions (carotid atherosclerotic lesions, stroke, coronary heart disease, diabetes mellitus, hypertension [definition includes use of medication], ever smokers, use of cholesterol lowering medication, BMI ≥ 30, or LDL-cholesterol >160 mg/dl) at baseline. The observed/expected ratios for the RCCA parameter were ranked and persons in the upper 50th percentile were classified as having the RCCA measure enlarged.


B-mode ultrasound common carotid artery intima-media thickness and external diameter: cross-sectional and longitudinal associations with carotid atherosclerosis in a large population sample.

Eigenbrodt ML, Bursac Z, Tracy RE, Mehta JL, Rose KM, Couper DJ - Cardiovasc Ultrasound (2008)

Representation of four arterial phenotypes based on enlargement of arterial wall thickness and external diameter. EEM = interface of media and adventitia. IMT = indicates normal intima-media thickness. L = interface of intima with lumen. Large bracket indicates normal external diameter.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2277382&req=5

Figure 1: Representation of four arterial phenotypes based on enlargement of arterial wall thickness and external diameter. EEM = interface of media and adventitia. IMT = indicates normal intima-media thickness. L = interface of intima with lumen. Large bracket indicates normal external diameter.
Mentions: We also investigated the association of four arterial phenotypes at baseline with carotid atherosclerosis progression. The baseline arterial phenotypes consisted of isolated or concurrent enlargement of RCCA diameter and IMT or neither (See Figure 1). The 50th percentile value of each vascular parameter for men and women was used to classify persons as having an enlarged RCCA IMT (men: ≥0.66 mm; women: ≥0.61 mm) and/or diameter (men: ≥8.06 mm; women: ≥7.30 mm). To check the robustness of this approach, separate categorizations were based on the observed to expected ratio values for IMT and diameter. Expected IMT and diameter values were calculated for each participant based on gender-specific betas for age, race, and height determined from linear regression analyses performed on a subset of participants who were free of atherosclerotic-related conditions (carotid atherosclerotic lesions, stroke, coronary heart disease, diabetes mellitus, hypertension [definition includes use of medication], ever smokers, use of cholesterol lowering medication, BMI ≥ 30, or LDL-cholesterol >160 mg/dl) at baseline. The observed/expected ratios for the RCCA parameter were ranked and persons in the upper 50th percentile were classified as having the RCCA measure enlarged.

Bottom Line: Each standard deviation increment of baseline RCCA diameter was associated with increasing carotid lesion prevalence (unadjusted odds ratio [OR] = 1.54, 95% confidence interval [CI] = 1.47-1.62) and with progression of carotid atherosclerosis (unadjusted hazards ratio (HR) = 1.37, 95% CI = 1.28-1.46); and the associations remained significant even after adjustment for IMT and risk factors (prevalence OR = 1.11, 95% CI = 1.04-1.18; progression HR = 1.11, 95% CI = 1.03-1.19).Controlling for gender, age and race, persons with both RCCA IMT and diameter in the upper 50th percentiles had the greatest risk of progressing to clearly defined carotid atherosclerotic lesions (all HR = 1.71, 95% CI = 1.47-2.0; men HR = 1.88, 95% CI = 1.48-2.39; women HR = 1.59, 95% CI = 1.31-1.95) while RCCA IMT or diameter alone in the upper 50th percentile produced significantly lower estimated risks.RCCA IMT and external diameter provide partially overlapping information relating to carotid atherosclerotic lesions.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Epidemiology, Fay W, Boozman College of Public Health, University of Arkansas for Medical Sciences, Little Rock, AR, USA. meigenbrodt@sbcglobal.net

ABSTRACT

Background: Arterial diameter and intima-media thickness (IMT) enlargement may each be related to the atherosclerotic process. Their separate or combined enlargement may indicate different arterial phenotypes with different atherosclerosis risk.

Methods: We investigated cross-sectional (baseline 1987-89: n = 7956) and prospective (median follow-up = 5.9 years: n = 4845) associations between baseline right common carotid artery (RCCA) external diameter and IMT with existing and incident carotid atherosclerotic lesions detected by B-mode ultrasound in any right or left carotid segments. Logistic regression models (unadjusted, adjusted for IMT, or adjusted for IMT and risk factors) were used to relate baseline diameter to existing carotid lesions while comparably adjusted parametric survival models assessed baseline diameter associations with carotid atherosclerosis progression (incident carotid lesions). Four baseline arterial phenotypes were categorized as having 1) neither IMT nor diameter enlarged (reference), 2) isolated IMT thickening, 3) isolated diameter enlargement, and 4) enlargement of both IMT and diameter. The association between these phenotypes and progression to definitive carotid atherosclerotic lesions was assessed over the follow-up period.

Results: Each standard deviation increment of baseline RCCA diameter was associated with increasing carotid lesion prevalence (unadjusted odds ratio [OR] = 1.54, 95% confidence interval [CI] = 1.47-1.62) and with progression of carotid atherosclerosis (unadjusted hazards ratio (HR) = 1.37, 95% CI = 1.28-1.46); and the associations remained significant even after adjustment for IMT and risk factors (prevalence OR = 1.11, 95% CI = 1.04-1.18; progression HR = 1.11, 95% CI = 1.03-1.19). Controlling for gender, age and race, persons with both RCCA IMT and diameter in the upper 50th percentiles had the greatest risk of progressing to clearly defined carotid atherosclerotic lesions (all HR = 1.71, 95% CI = 1.47-2.0; men HR = 1.88, 95% CI = 1.48-2.39; women HR = 1.59, 95% CI = 1.31-1.95) while RCCA IMT or diameter alone in the upper 50th percentile produced significantly lower estimated risks.

Conclusion: RCCA IMT and external diameter provide partially overlapping information relating to carotid atherosclerotic lesions. More importantly, the RCCA phenotype of coexistent wall thickening with external diameter enlargement indicates higher atherosclerotic risk than isolated wall thickening or diameter enlargement.

Show MeSH
Related in: MedlinePlus