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1.  Variations in Common Carotid Artery Intima-Media Thickness (cIMT) during the Cardiac Cycle: Implications for Cardiovascular Risk Assessment 
Introduction
Common carotid artery (CCA) intima-media thickness (cIMT), a measure of atherosclerosis, varies between peak-systole (PS) and end-diastole (ED). This difference might affect cardiovascular risk assessment.
Materials and methods
IMT measurements of the right and left CCA were synchronized with an electrocardiogram: R-wave for ED and T-wave for PS. IMT was measured in 2930 members of the Framingham Offspring Study. Multivariable regression models were generated with ED-IMT, PS-IMT and change in IMT as dependent variables and Framingham risk factors as independent variables. ED-IMT estimates were compared to the upper quartile of IMT based on normative data obtained at PS.
Results
The average age of our population was 57.9 years. Average difference in IMT during the cardiac cycle was 0.037 mm (95% CI: 0.035–0.038 mm). ED-IMT and PS-IMT had similar associations with Framingham risk factors (total R2= 0.292 versus 0.275) and were significantly associated with all risk factors. In a fully adjusted multivariable model, a thinner IMT at peak-systole was associated with pulse pressure (p < 0.0001), LDL-cholesterol (p = 0.0064), age (p = 0.046), and no other risk factors. Performing ED-IMT measurements while using upper quartile PS-IMT normative data lead to inappropriately increasing by 42.1% the number of individuals in the fourth IMT quartile (high cardiovascular risk category).
Conclusion
The difference in IMT between peak-systole and end-diastole is associated with pulse pressure, LDL-cholesterol, and age. In our study, mean IMT difference during the cardiac cycle lead to an overestimation by 42.1% of individuals at high risk for cardiovascular disease.
doi:10.1016/j.echo.2012.05.007
PMCID: PMC3544292  PMID: 22721828
Ultrasonics; Risk Factors; Carotid Arteries; Blood Pressure; systole; diastole
2.  Examining the association between salivary cortisol levels and subclinical measures of atherosclerosis: the Multi-Ethnic Study of Atherosclerosis 
Psychoneuroendocrinology  2012;38(7):1036-1046.
Objective
To investigate the association between salivary cortisol and two markers of subclinical cardiovascular disease (CVD), coronary calcification (CAC), and ankle-brachial index (ABI).
Methods
Data from an ancillary study to the Multi-Ethnic Study of Atherosclerosis (MESA), the MESA Stress Study, were used to analyze associations of salivary cortisol data collected six times per day over three days with CAC and ABI. The authors used mixed models with repeat cortisol measures nested within persons to determine if specific features of the cortisol profile were associated with CAC and ABI.
Results
total of 464 participants were included in the CAC analysis and 610 in the ABI analysis. The mean age of participants was 65.6 years. A 1-unit increase in log coronary calcium was associated with a 1.77% flatter early decline in cortisol (95% CI: 0.23, 3.34) among men and women combined. Among women low ABI was associated with a steeper early decline (−13.95% CI:−25.58, −3.39) and a marginally statistically significant flatter late decline (1.39% CI: −0.009, 2.81). The cortisol area under the curve and wake to bedtime slope were not associated with subclinical CVD.
Conclusions
This study provides weak support for the link between cortisol and measures of subclinical atherosclerosis. We found an association between some features of the diurnal cortisol profile and coronary calcification and ABI but associations were not consistent across subclinical measures. There are methodological challenges in detecting associations of cortisol measures at a point in time with health outcomes that develop over a lifetime. Studies of short-term mechanisms linking stress to physiological processes related to the development of early atherosclerosis may be more informative.
doi:10.1016/j.psyneuen.2012.10.007
PMCID: PMC4020284  PMID: 23146655
salivary cortisol; ankle brachial index; coronary calcification; atherosclerosis; stress; cortisol awakening response; cortisol diurnal pattern; Multi-Ethnic Study of Atherosclerosis
3.  Changes in Carotid Intima-Media Thickness During the Cardiac Cycle: The Multi-Ethnic Study of Atherosclerosis 
Background
Common carotid artery intima-media thickness (IMT), a measure of subclinical cardiovascular disease, changes during the cardiac cycle. The magnitude of this effect and its implications have not been well studied.
Methods and Results
Far-wall IMT measurements of the right common carotid artery were measured at end diastole and peak systole in 5633 individuals from the Multi-Ethnic Study of Atherosclerosis (MESA). Multivariable regression models were generated with end-diastolic IMT, peak-systolic IMT, and change in IMT during the cardiac cycle as dependent variables and traditional cardiovascular risk factors as independent variables. The average age of our population was 61.9 (45 to 84) years. Average change in carotid IMT during the cardiac cycle was 0.041 mm (95% confidence interval: 0.039 to 0.042 mm), with a mean IMT of 0.68 mm. End-diastolic IMT and peak-systolic IMT were similarly associated with risk factors. In a fully adjusted model, change in carotid IMT during the cardiac cycle was associated with ethnicity and pulse pressure (P=0.001) and not age, sex, or other risk factors. Chinese and Hispanics had less of a change in IMT than did non-Hispanic whites. With peak-systolic IMT reference values used as normative data, 31.3% more individuals were classified as being in the upper quartile of IMT and at high risk for cardiovascular disease than would be expected when IMT is measured at end diastole.
Conclusions
Measurable differences in IMT are seen during the cardiac cycle. This affects the interpretation of IMT measurements used for cardiovascular risk assessment, given published normative data with IMT measured at peak systole.
Clinical Trial Registration
URL: www.ClinicalTrials.gov. Unique identifier: NCT00063440. (J Am Heart Assoc. 2012;1:e001420 doi: 10.1161/JAHA.112.001420.)
doi:10.1161/JAHA.112.001420
PMCID: PMC3487346  PMID: 23130162
atherosclerosis; blood pressure; carotid arteries; diastole; epidemiology; risk factors; systole; ultrasonics
4.  Associations Between a Parental History of Premature Cardiovascular Disease and Coronary Calcium and Carotid Intima-Media Thickness: The Coronary Artery Risk Development In Young Adults (CARDIA) Study 
Background
It is unclear if associations between a parental history of premature CVD (pCVD) and subclinical atherosclerosis are attenuated by adjustment for long-term risk factors levels through middle adulthood.
Design
Prospective community-based cohort study
Methods
CARDIA participants who attended the year 20 exam (N=2283, mean age 45 years) were grouped by pCVD status: maternal only, paternal only, any parental, and no parental history (referent). We used separate logistic regression models, adjusted for average risk factor levels over 20 years' follow-up to assess associations of parental pCVD and subclinical atherosclerosis in offspring.
Results
White participants with any parental history of pCVD had a higher odds of CAC>0 than participants with no parental history (OR 1.55; 95% CI, 1.01-2.37). This was largely driven by the association of a paternal history of pCVD with CAC>0 (OR 2.15; 95% CI, 1.42-3.23), which was minimally attenuated by multivariable adjustment (OR 2.09; 95% CI, 1.31-3.32). Similarly, adjusted associations between parental pCVD and IMT > 90%tile were observed in white participants with a paternal history of pCVD (OR=1.93; 95% CI, 1.10-3.39) and any parental history pCVD (OR 1.67; 95% CI, 1.02-2.74). No significant associations between a parental history of pCVD and the odds of subclinical atherosclerosis were observed in black participants.
Conclusions
Parental pCVD is independently associated with early development of subclinical atherosclerosis; these associations may be race-specific for participants in their 5th decade of life.
doi:10.1177/2047487312462801
PMCID: PMC3779512  PMID: 23027592
Family History of Premature Cardiovascular Disease; Coronary Artery Calcium; Carotid Intima-Media Thickness
5.  Carotid intima-media thickness progression to predict cardiovascular events in the general population (the PROG-IMT collaborative project): a meta-analysis of individual participant data 
Lancet  2012;379(9831):2053-2062.
Summary
Background
Carotid intima-media thickness (cIMT) is related to the risk of cardiovascular events in the general population. An association between changes in cIMT and cardiovascular risk is frequently assumed but has rarely been reported. Our aim was to test this association.
Methods
We identified general population studies that assessed cIMT at least twice and followed up participants for myocardial infarction, stroke, or death. The study teams collaborated in an individual participant data meta-analysis. Excluding individuals with previous myocardial infarction or stroke, we assessed the association between cIMT progression and the risk of cardiovascular events (myocardial infarction, stroke, vascular death, or a combination of these) for each study with Cox regression. The log hazard ratios (HRs) per SD difference were pooled by random effects meta-analysis.
Findings
Of 21 eligible studies, 16 with 36 984 participants were included. During a mean follow-up of 7·0 years, 1519 myocardial infarctions, 1339 strokes, and 2028 combined endpoints (myocardial infarction, stroke, vascular death) occurred. Yearly cIMT progression was derived from two ultrasound visits 2–7 years (median 4 years) apart. For mean common carotid artery intima-media thickness progression, the overall HR of the combined endpoint was 0·97 (95% CI 0·94–1·00) when adjusted for age, sex, and mean common carotid artery intima-media thickness, and 0·98 (0·95–1·01) when also adjusted for vascular risk factors. Although we detected no associations with cIMT progression in sensitivity analyses, the mean cIMT of the two ultrasound scans was positively and robustly associated with cardiovascular risk (HR for the combined endpoint 1·16, 95% CI 1·10–1·22, adjusted for age, sex, mean common carotid artery intima-media thickness progression, and vascular risk factors). In three studies including 3439 participants who had four ultrasound scans, cIMT progression did not correlate between occassions (reproducibility correlations between r=−0·06 and r=−0·02).
Interpretation
The association between cIMT progression assessed from two ultrasound scans and cardiovascular risk in the general population remains unproven. No conclusion can be derived for the use of cIMT progression as a surrogate in clinical trials.
Funding
Deutsche Forschungsgemeinschaft.
doi:10.1016/S0140-6736(12)60441-3
PMCID: PMC3918517  PMID: 22541275
6.  Vascular Responses to Long- and Short-Term Exposure to Fine Particulate Matter 
Objectives
This study evaluated the association of long- and short-term air pollutant exposures with flow-mediated dilation (FMD) and baseline arterial diameter (BAD) of the brachial artery using ultrasound in a large multicity cohort.
Background
Exposures to ambient air pollution, especially long-term exposure to particulate matter <2.5 μm in aerodynamic diameter (PM2.5), are linked with cardiovascular mortality. Short-term exposure to PM2.5 has been associated with decreased FMD and vasoconstriction, suggesting that adverse effects of PM2.5 may involve endothelial dysfunction. However, long-term effects of PM2.5 on endothelial dysfunction have not been investigated.
Methods
FMD and BAD were measured by brachial artery ultrasound at the initial examination of the Multi-Ethnic Study of Atherosclerosis. Long-term PM2.5 concentrations were estimated for the year 2000 at each participant’s residence (n = 3,040) using a spatio-temporal model informed by cohort-specific monitoring. Short-term PM2.5 concentrations were based on daily central-site monitoring in each of the 6 cities.
Results
An interquartile increase in long-term PM2.5 concentration (3 μg/m3) was associated with a 0.3% decrease in FMD (95% confidence interval [CI] of difference: −0.6 to −0.03; p = 0.03), adjusting for demographic characteristics, traditional risk factors, sonographers, and 1/BAD. Women, nonsmokers, younger participants, and those with hypertension seemed to show a greater association of PM2.5 with FMD. FMD was not significantly associated with short-term variation in PM2.5 (−0.1% per 12 μg/m3 daily increase [95% CI: −0.2 to 0.04] on the day before examination).
Conclusions
Long-term PM2.5 exposure was significantly associated with decreased endothelial function according to brachial ultrasound results. These findings may elucidate an important pathway linking air pollution and cardiovascular mortality.
doi:10.1016/j.jacc.2012.08.973
PMCID: PMC3665082  PMID: 23103035
air pollution; atherosclerosis; cardiovascular mortality; endothelial function; flow-mediated dilation; traffic
7.  Association of number of live births with left ventricular structure and function. The Multi-Ethnic Study of Atherosclerosis (MESA) 
American heart journal  2012;163(3):470-476.
Background
Pregnancy is associated with marked maternal cardiovascular/hemodynamic changes. A greater number of pregnancies may be associated with long-term subclinical changes in left ventricular (LV) remodeling.
Methods
Among 2,234 white, black, Hispanic, and Chinese women (mean age 62 years) in the MESA, we used linear regression to relate live births and cardiac magnetic resonance imaging LV measures. Covariates included age, ethnicity, height, income, education, birth country, smoking, menopause, and oral contraceptive duration. Models were additionally adjusted for potential mediators: systolic blood pressure, antihypertensive use, total/high-density lipoprotein cholesterol, triglycerides, diabetes, and body mass index. We performed sensitivity analyses excluding 763 women in the lowest socioeconomic group: annual income <$25,000 and lower high school level of education.
Results
With each live birth, LV mass increased 1.26 g; LV end-diastolic volume, 0.74 mL; and LV end-systolic volume, 0.45 mL; LV ejection fraction decreased 0.18% (P trend <0.05). Changes were most notable for the category of women with ≥5 pregnancies. Upon adjustment for potential biologic mediators, live births remained positively associated with LV mass and end-systolic volume. Live births remained significantly associated with LV end-systolic, end-diastolic volumes, and LV mass (P trend ≤0.02) after excluding women in the lowest socioeconomic group.
Conclusions
Number of live births is associated with key LV structural and functional measures in middle to older ages, even after adjustment for sociodemographic factors and cardiovascular disease risk factors. Hemodynamic changes during pregnancy may be associated with cardiac structure/function beyond childbearing years.
doi:10.1016/j.ahj.2011.12.011
PMCID: PMC3656723  PMID: 22424019

Results 1-7 (7)