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Biomedical subjects

Susan E Aeschlimann

Publications and source records attributed to Susan E Aeschlimann.

11 recordsLinked to original sources

Validation of a carotid intima-media thickness border detection program for use in an office setting.

BACKGROUND: A unique semiautomated border detection program (BDP) designed for use on a personal computer was evaluated to determine whether: (1) carotid intima-media thickness (CIMT) measurements were bioequivalent to a reference laboratory; and (2) it would allow a novice (NOV) reader with no medical training to accurately and reproducibly measure CIMT. METHODS: Far-wall CIMT was measured blindly and in duplicate by an experienced and NOV reader using BDP and by a reference laboratory. RESULTS: Mean CIMT using BDP was bioequivalent to the reference laboratory (two 1-sided T-test, P < .05) with small absolute differences (experienced 0.011 +/- 0.004 mm, NOV 0.022 +/- 0.004 mm). Reproducibility was high, with small coefficients of variation when used by either the experienced (3.1%) or NOV (7.8%) reader. CONCLUSION: CIMT measurements using BDP were accurate and reproducible. It was mastered easily by a NOV reader and appeared suitable for use in an office setting.

Adult↗

Use of carotid intima-media thickness and vascular age to modify cardiovascular risk prediction.

BACKGROUND: This study identified predictors of patients for whom carotid artery intima-media thickness (CIMT) measurement and determination of vascular age could change cardiovascular disease (CVD) risk assessment. METHODS: We studied consecutive patients who were asymptomatic and nondiabetic, referred for ultrasound measurement of CIMT. Individuals with CIMT 75th percentile or greater for age, sex, and race were defined as having advanced subclinical atherosclerosis. CIMT values were converted to vascular age estimates and were used to modify Framingham 10-year CVD risk estimates. RESULTS: Of 506 patients, 261 (51.6%) were not taking lipid-lowering therapy. Advanced subclinical atherosclerosis was present in 77 (30%). There were 62 patients (23.8%) with a change in CVD risk of 5% or more. Predictors of 5% or more change in CVD risk were systolic blood pressure (P < .001), total/high-density lipoprotein cholesterol ratio (P < .001), and male sex (P < .001). Of the 97 patients at moderate or moderately high risk, 56.7% changed risk classification. CONCLUSIONS: Measurement of CIMT and determination of vascular age can identify individuals with advanced subclinical atherosclerosis, resulting in clinically meaningful alterations in CVD risk estimates.

Adult↗

Use of hand-held ultrasound by a nonsonographer clinician to measure carotid intima-media thickness.

OBJECTIVE: We sought to evaluate the accuracy of carotid intima-media thickness (CIMT) measurements by a nonsonographer clinician using hand-held ultrasound (HHU). BACKGROUND: Use of a HHU for point-of-care CIMT measurement has not been tested previously. METHODS: Participants underwent reference ultrasound and HHU studies. HHU validity was tested by an expert sonographer. Nonsonographer clinician accuracy using the HHU was tested against the expert sonographer. CIMT bioequivalence was tested with .5 pixel limits. RESULTS: The 75 participants were (mean [SD]) 55 [7] years old. CIMT values were bioequivalent (0.714 [0.029] vs 0.685 [0.029] mm, phase I; 0.697 [0.015] vs 0.687 [0.015] mm, phase II; P(two 1-sided t test) < .05). Agreement was 80% for CIMT classifications (intraclass correlation coefficient = 0.451, P < .001) and 90% for plaque presence (intraclass correlation coefficient = 0.797, P < .001). CONCLUSIONS: CIMT measured by HHU was bioequivalent to a reference ultrasound system, when used by an expert sonographer or nonsonographer clinician. Clinical classifications by CIMT quartile and plaque presence were similar. HHU may be suitable for office-based atherosclerosis screening.

Carotid Arteries↗

Is the ankle-brachial index a useful screening test for subclinical atherosclerosis in asymptomatic, middle-aged adults?

BACKGROUND: Measurement of the ankle-brachial index (ABI) is recommended as a screening test for cardiovascular risk prediction in individuals > or = 50 years old; however, there is little data regarding the utility of the ABI as a screening test in individuals for whom physicians actually order non-invasive testing for cardiovascular risk prediction. METHODS: This study included 493 consecutive asymptomatic patients without known atherosclerotic vascular disease who were referred by their physician for measurement of the ABI and ultrasound measurement of carotid intima-media thickness (CIMT). ABI values were classified as "reduced" (<0.9), "normal" (0.9-1.3), and "increased" (>1.3). RESULTS: The mean age of the patients was 55.3 (standard deviation 7.5) years. Only 1 patient had a reduced ABI (0.2%). ABI values tended to be higher in those with increased CIMT (P=0.051); however, CIMT was not significantly different between those with normal and increased ABI values (P=0.802). There were no significant differences in the prevalence of traditional cardiovascular risk factors or carotid plaque presence among the ABI groups. CONCLUSIONS: Despite recommendations, the ABI is not sensitive as a screening tool for detecting subclinical atherosclerosis in asymptomatic middle-aged individuals.

Ankle↗

Skin cholesterol content identifies increased carotid intima-media thickness in asymptomatic adults.

BACKGROUND: A noninvasive assay to measure skin Tc recently has become available for use in the outpatient setting as a cardiovascular (CV) risk prediction tool. The purpose of this study was to determine whether skin tissue cholesterol content (skin Tc) levels are associated with increased carotid intima-media thickness (CIMT) after adjusting for known CV risk factors and Framingham CV risk. METHODS: Consecutive patients without known vascular disease who were referred for determination of CIMT underwent B-mode ultrasonography of the carotid arteries and measurement of skin Tc using a noninvasive assay. Use of medications, cardiac risk factors, and Framingham 10-year CV risk were determined prospectively. Multivariable regression was used to determine predictors of increased CIMT. RESULTS: Among 81 subjects, the mean (SD) age was 55.6 (7.7) years and the mean skin Tc was 95.9 (18.3) U. Carotid intima-media thickness was significantly higher among individuals in the highest quartile of skin Tc (0.87 vs 0.76 mm, P = .011). In multivariable analyses, skin Tc was associated with increased CIMT even after adjusting for age, sex, glucose, systolic blood pressure, total/high-density lipoprotein cholesterol ratio, and use of lipid-lowering therapy (odds ratio [OR] per 10-unit increase = 1.590, 95% CI 1.525-1.658, P = .031). Skin Tc also was associated with increased CIMT after adjustment for Framingham risk (OR = 1.341, 95% CI 1.302-1.380, P = .048). CONCLUSIONS: Skin Tc is an easy-to-measure, noninvasive marker that can help identify subclinical atherosclerosis in asymptomatic middle-aged adults, even after controlling for risk factors and CV risk predicted by the Framingham model.

Adult↗

Ultrasound-detected carotid plaque as a screening tool for advanced subclinical atherosclerosis.

BACKGROUND: There is great need for a simple, noninvasive tool that can be used in an office setting to screen for subclinical atherosclerosis. In patients referred for cardiovascular (CV) risk assessment, we evaluated the ability of ultrasound screening for carotid plaque to identify patients with advanced subclinical atherosclerosis. METHODS: Consecutive asymptomatic patients without vascular disease referred by their physician for measurement of the ankle-brachial pressure index and carotid intima-media thickness (CIMT) were included. Carotid intima-media thickness was measured using the standardized ultrasound protocol from the Atherosclerosis Risk in Communities (ARIC) study. Advanced atherosclerosis was defined as CIMT > or = 75th percentile for age, sex, and race in ARIC. RESULTS: The mean age of the 327 subjects was 55.4 years (SD 7.7 years). The 10-year Framingham CV risk was 5.1% (4.8%). In a multiple logistic regression model that included Framingham CV risk, ankle-brachial pressure index, and use of lipid-lowering medications, plaque presence significantly predicted advanced atherosclerosis (odds ratio 3.08, 95% CI 1.91-4.96, P < .001). In stepwise regression models that included age, body mass index, current tobacco use, family history of premature CV disease, fasting glucose, sex, systolic blood pressure, total/high-density lipoprotein cholesterol ratio, and use of antihypertensive and lipid-lowering medications, plaque presence independently predicted advanced atherosclerosis (P < .001). CONCLUSION: Ultrasound detection of carotid plaque helped identify asymptomatic patients with advanced subclinical atherosclerosis. Screening for carotid plaque is easier than determination of CIMT and may help detect asymptomatic patients at increased CV risk.

Carotid Artery Diseases↗

Vascular age: integrating carotid intima-media thickness measurements with global coronary risk assessment.

BACKGROUND: An imaging test that quantifies atherosclerotic burden and that can be integrated with existing risk stratification paradigms would be a very useful clinical tool. HYPOTHESIS: Measurement of carotid intima-media thickness (CIMT) is feasible in a clinical setting. Such measurements can be integrated into coronary risk assessment models. METHODS: Carotid intima-media thickness was measured by B-mode ultrasound in 82 consecutive patients without manifest atherosclerotic vascular disease. The values were used to determine "vascular age" (VA) based on nomograms from the Atherosclerosis Risk in Communities study. Vascular age was substituted for chronological age and standard and vascular age-adjusted 10-year coronary heart disease (CHD) risk estimates were compared. RESULTS: The mean chronological age was 55.8 +/- 9.0 years. The mean VA using CIMT was 65.5 +/- 18.9 years (p < 0.001). The Framingham 10-year hard CHD risk estimate was 6.5 +/- 4.9%. Substituting CIMT-derived VA for chronological age increased the 10-year CHD risk estimate to 8.0 +/- 6.8% (p < 0.001). Of 14 subjects initially at intermediate risk, 5 (35.7%) were reclassified as higher risk and 2 (14.3%) were reclassified as lower risk. Significant predictors of reclassification were tobacco use, high-density lipoprotein cholesterol, systolic blood pressure, and low-density lipoprotein cholesterol. CONCLUSIONS: Measurement of CIMT, a noninvasive estimate of current atherosclerotic burden, is feasible in a clinical setting and can be integrated into CHD risk assessment models. Determining VA using CIMT values may help individualize the age component of population-based CHD risk estimates. This strategy should be tested in a large trial with hard clinical endpoints.

Adult↗

Effects of pravastatin on lipoproteins and endothelial function in patients receiving human immunodeficiency virus protease inhibitors.

BACKGROUND: Although recommended as initial therapy for patients with dyslipidemia who are taking human immunodeficiency virus protease inhibitors (HIV PIs), the effects of pravastatin on lipoproteins and arterial reactivity have not been elucidated. The purpose of this study was to determine the effects of pravastatin on lipoprotein subfractions and endothelial function in patients with dyslipidemia who are receiving HIV PIs. METHODS: This was a placebo-controlled, double-blind, crossover study comparing pravastatin (40 mg) to placebo in 20 patients who were taking HIV PIs. Lipoprotein subfractions were measured with nuclear magnetic resonance spectroscopic analysis. Flow-mediated vasodilation (FMD) of the brachial artery was evaluated with high-resolution ultrasound scanning. RESULTS: At baseline, subjects had an increased concentration of low-density lipoprotein (LDL) particles (1756 +/- 180 nmol/L), which tended to be small (19.9 +/- 0.2 nm), a low concentration of large high-density lipoproteins (HDL; 0.94 +/- 0.07 mmol/L), and an increased concentration of large very low-density lipoproteins (VLDL; 1.90 +/- 0.58 mmol/L). FMD was impaired (4.5% +/- 1.1%). Compared with placebo, pravastatin resulted in a 20.8% reduction in LDL particles (P =.030), a 26.7% reduction in small LDL (P =.100), and a 44.9% reduction in small VLDL (P =.023). Total and non-HDL cholesterol levels decreased by 18.3% (P <.001) and 21.7% (P <.001), respectively. FMD tended to increase in patients receiving pravastatin (0.7% +/- 0.6%); however, the difference between treatment phases was not statistically significant (P =.080). CONCLUSIONS: This is the first double-blind, placebo-controlled study of the effects of statin therapy on lipids, lipoprotein subfractions, and endothelial function in patients taking HIV PIs. Pravastatin reduced concentrations of atherogenic lipoproteins, particularly those most associated with future coronary events.

Adult↗

Effects of multivitamins and low-dose folic acid supplements on flow-mediated vasodilation and plasma homocysteine levels in older adults.

BACKGROUND: Hyperhomocysteinemia is associated with aging, endothelial dysfunction, and increased risk of coronary heart disease in older adults; however, the effects of homocysteine-lowering therapy on vascular reactivity in older persons are unknown. The objective of this study was to determine the effects of multivitamins (MV) and folic acid (FA) supplements on flow-mediated vasodilation (FMD) in older adults. METHODS: Individuals > or =70 years old with homocysteine levels > or =10 micromol/L were recruited for this 40-week, prospective, single-blinded study. All subjects were treated sequentially, with each of the following daily therapies for 10 weeks: (1) placebo, (2) MV (400 microg FA, 6 mg vitamin B6, 25 microg vitamin B12), (3) placebo, then (4) MV + FA (total FA, 1400 microg). FMD, folate intake, and laboratory values were measured at each visit. Investigators were blinded to subject treatment phase when measuring vessel diameters and calculating FMD. RESULTS: Twenty subjects (mean +/- SEM age, 78.0 +/- 1.2 [range, 70 to 88] years, 9 women) completed the MV and 17 completed the MV + FA interventions. FMD was impaired at baseline (2.0% +/- 1.2%). During the 40-week study, homocysteine levels decreased by 1.4 +/- 0.9 micromol/L (p(trend) = 0.034) from a baseline of 12.8 +/- 0.6 micromol/L; however, FMD did not change significantly (p(trend) = 0.874). FMD did not improve after therapy with MV alone (3.0% +/- 0.9% [week 10] vs 2.4% +/- 1.1% [week 20], P =.716) or with MV + FA (2.6% +/- 0.9% [week 30] vs 1.9% +/- 0.7% [week 40], P =.484). CONCLUSIONS: At doses commonly prescribed in clinical practice, MV and FA supplements did not improve FMD in older adults with hyperhomocysteinemia.

Aged↗