Palopegteriparatide Treatment Improves Renal Function in Adults with Chronic Hypoparathyroidism: 1-Year Results from the Phase 3 PaTHway Trial

INTRODUCTION

Individuals with chronic hypoparathyroidism managed with conventional therapy (active vitamin D and calcium) have an increased risk for renal dysfunction versus age- and sex-matched controls. Treatments that replace the physiologic effects of parathyroid hormone (PTH) while reducing the need for conventional therapy may help prevent a decline in renal function in this population. This post hoc analysis examined the impact of palopegteriparatide treatment on renal function in adults with chronic hypoparathyroidism.

METHODS

PaTHway is a phase 3 trial of palopegteriparatide in adults with chronic hypoparathyroidism that included a randomized, double-blind, placebo-controlled 26-week period followed by an ongoing 156-week open-label extension (OLE) period. Changes in renal function over 52 weeks (26 weeks blinded + 26 weeks OLE) were assessed using estimated glomerular filtration rate (eGFR). A subgroup analysis was performed with participants stratified by baseline eGFR < 60 or ≥ 60 mL/min/1.73 m2.

RESULTS

At week 52, over 95% (78/82) of participants remained enrolled in the OLE and of those, 86% maintained normocalcemia and 95% achieved independence from conventional therapy (no active vitamin D and ≤ 600 mg/day of calcium), with none requiring active vitamin D. Treatment with palopegteriparatide over 52 weeks resulted in a mean (SD) increase in eGFR of 9.3 (11.7) mL/min/1.73 m2 from baseline (P < 0.0001) and 43% of participants had an increase ≥ 10 mL/min/1.73 m2. In participants with baseline eGFR < 60 mL/min/1.73 m2, 52 weeks of treatment with palopegteriparatide resulted in a mean (SD) increase of 11.5 (11.3) mL/min/1.73 m2 (P < 0.001). One case of nephrolithiasis was reported for a participant in the placebo group during blinded treatment; none were reported through week 52 with palopegteriparatide.

CONCLUSION

In this post hoc analysis of the PaTHway trial, palopegteriparatide treatment was associated with significantly improved eGFR at week 52 in addition to previously reported maintenance and normalization of serum and urine biochemistries. Further investigation of palopegteriparatide for the preservation of renal function in hypoparathyroidism is warranted.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04701203.

Efficacy and Safety of Parathyroid Hormone Replacement With TransCon PTH in Hypoparathyroidism: 26-Week Results From the Phase 3 PaTHway Trial

Conventional therapy for hypoparathyroidism consisting of active vitamin D and calcium aims to alleviate hypocalcemia but fails to restore normal parathyroid hormone (PTH) physiology. PTH replacement therapy is the ideal physiologic treatment for hypoparathyroidism. The double-blind, placebo-controlled, 26-week, phase 3 PaTHway trial assessed the efficacy and safety of PTH replacement therapy for hypoparathyroidism individuals with the investigational drug TransCon PTH (palopegteriparatide). Participants (n = 84) were randomized 3:1 to once-daily TransCon PTH (initially 18 μg/d) or placebo, both co-administered with conventional therapy. The study drug and conventional therapy were titrated according to a dosing algorithm guided by serum calcium. The composite primary efficacy endpoint was the proportion of participants at week 26 who achieved normal albumin-adjusted serum calcium levels (8.3-10.6 mg/dL), independence from conventional therapy (requiring no active vitamin D and ≤600 mg/d of calcium), and no increase in study drug over 4 weeks before week 26. Other outcomes of interest included health-related quality of life measured by the 36-Item Short Form Survey (SF-36), hypoparathyroidism-related symptoms, functioning, and well-being measured by the Hypoparathyroidism Patient Experience Scale (HPES), and urinary calcium excretion. At week 26, 79% (48/61) of participants treated with TransCon PTH versus 5% (1/21) wiplacebo met the composite primary efficacy endpoint (p < 0.0001). TransCon PTH treatment demonstrated a significant improvement in all key secondary endpoint HPES domain scores (all p < 0.01) and the SF-36 Physical Functioning subscale score (p = 0.0347) compared with placebo. Additionally, 93% (57/61) of participants treated with TransCon PTH achieved independence from conventional therapy. TransCon PTH treatment normalized mean 24-hour urine calcium. Overall, 82% (50/61) treated with TransCon PTH and 100% (21/21) wiplacebo experienced adverse events; most were mild (46%) or moderate (46%). No study drug-related withdrawals occurred. In conclusion, TransCon PTH maintained normocalcemia while permitting independence from conventional therapy and was well-tolerated in individuals with hypoparathyroidism. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Coronary CT Angiography and Carotid MRI Improve Phenotyping of Disease Extent Compared with ACC/AHA Risk Score Alone

PURPOSE

To determine the relationship between the American College of Cardiology/American Heart Association (ACC/AHA) risk score and plaque phenotype of the coronary and carotid arteries assessed directly using CT angiography and MRI.

MATERIALS AND METHODS

Asymptomatic subjects eligible for statin therapy by risk score were enrolled in a prospective study of disease burden using coronary artery calcium (CAC) scoring, coronary CT angiography, and MRI of the carotid arteries. Quartiles were calculated for noncalcified plaque, CAC, and average carotid wall volume and were compared with ACC/AHA risk quartiles.

RESULTS

Two hundred three subjects were studied (60% men; mean age, 65 years). There were weak correlations between risk and carotid wall volume (Kendall tau = 0.29), noncalcified plaque (tau = 0.16), and CAC (tau = 0.33). ACC/AHA risk alone misclassified plaque extent compared with measurement by carotid wall volume, CAC, and noncalcified plaque in 22.1%, 24.1%, and 29.6% of subjects, respectively. On average, 13% of the subjects were underclassified, and 12.5% were overclassified.

CONCLUSION

Approximately 25% of subjects had large discrepancies between ACC/AHA risk and plaque burden at imaging. These results suggest that clinical risk score models alone do not fully reflect the amount of atherosclerotic disease present.© RSNA, 2020See also the commentary by Truong and Villines in this issue.

Metabolically Healthy Obesity, Transition to Metabolic Syndrome, and Cardiovascular Risk

BACKGROUND

Debate over the cardiometabolic risk associated with metabolically healthy obesity (MHO) continues. Many studies have investigated this relationship by examining MHO at baseline with longitudinal follow-up, with inconsistent results.

OBJECTIVES

The authors hypothesized that MHO at baseline is transient and that transition to metabolic syndrome (MetS) and duration of MetS explains heterogeneity in incident cardiovascular disease (CVD) and all-cause mortality.

METHODS

Among 6,809 participants of the MESA (Multi-Ethnic Study of Atherosclerosis) the authors used Cox proportional hazards and logistic regression models to investigate the joint association of obesity (≥30 kg/m²) and MetS (International Diabetes Federation consensus definition) with CVD and mortality across a median of 12.2 years. We tested for interaction and conducted sensitivity analyses for a number of conditions.

RESULTS

Compared with metabolically healthy normal weight, baseline MHO was not significantly associated with incident CVD; however, almost one-half of those participants developed MetS during follow-up (unstable MHO). Those who had unstable MHO had increased odds of CVD (odds ratio [OR]: 1.60; 95% confidence interval [CI]: 1.14 to 2.25), compared with those with stable MHO or healthy normal weight. Dose response for duration of MetS was significantly and linearly associated with CVD (1 visit with MetS OR: 1.62; 95% CI: 1.27 to 2.07; 2 visits, OR: 1.92; 95% CI: 1.48 to 2.49; 3+ visits, OR: 2.33; 95% CI: 1.89 to 2.87; p value for trend <0.001) and MetS mediated approximately 62% (44% to 100%) of the relationship between obesity at any point during follow-up and CVD.

CONCLUSIONS

Metabolically healthy obesity is not a stable or reliable indicator of future risk for CVD. Weight loss and lifestyle management for CVD risk factors should be recommended to all individuals with obesity.

Myocardial T1 mapping and determination of partition coefficients at 3 tesla: comparison between gadobenate dimeglumine and gadofosveset trisodium

Objective

To compare an albumin-bound gadolinium chelate (gadofosveset trisodium) and an extracellular contrast agent (gadobenate dimeglumine), in terms of their effects on myocardial longitudinal (T1) relaxation time and partition coefficient.

Materials and Methods

Study subjects underwent two imaging sessions for T1 mapping at 3 tesla with a modified look-locker inversion recovery (MOLLI) pulse sequence to obtain one pre-contrast T1 map and two post-contrast T1 maps (mean 15 and 21 min, respectively). The partition coefficient was calculated as ΔR1_myocardium /ΔR1_blood , where R1 is 1/T1.

Results

A total of 252 myocardial and blood pool T1 values were obtained in 21 healthy subjects. After gadolinium administration, the myocardial T1 was longer for gadofosveset than for gadobenate, the mean difference between the two contrast agents being −7.6 ± 60 ms (p = 0.41). The inverse was true for the blood pool T1, which was longer for gadobenate than for gadofosveset, the mean difference being 56.5 ± 67 ms (p < 0.001). The partition coefficient (λ) was higher for gadobenate than gadofosveset (0.41 vs. 0.33), indicating slower blood pool washout for gadofosveset than for gadobenate.

Conclusion

Myocardial T1 times did not differ significantly between gadobenate and gadofosveset. At typical clinical doses of the contrast agents, partition coefficients were significantly lower for the intravascular contrast agent than for the extravascular agent.

Three-Dimensional Volumetric Assessment of Diastolic Function by Cardiac Magnetic Resonance Imaging: The Multi-Ethnic Study of Atherosclerosis (MESA)

Background:

Cardiac Magnetic Resonance is in need of a simple and robust method for diastolic function assessment that can be done with routine protocol sequences.

Objective:

To develop and validate a three-dimensional (3D) model-based volumetric assessment of diastolic function using cardiac magnetic resonance (CMR) imaging and compare the results obtained with the model with those obtained by echocardiography.

Methods:

The study participants provided written informed consent and were included if having undergone both echocardiography and cine steady-state free precession (SSFP) CMR on the same day. Guide points at the septal and lateral mitral annulus were used to define the early longitudinal relaxation rate (E'), while a time-volume curve from the 3D model was used to assess diastolic filling parameters. We determined the correlation between 3D CMR and echocardiography and the accuracy of CMR in classifying the diastolic function grade.

Results:

The study included 102 subjects. The E/A ratio by CMR was positively associated with the E/A ratio by echocardiography (r = 0.71, p < 0.0001). The early diastolic relaxation velocity by tissue Doppler and longitudinal relaxation rate for the lateral mitral annulus displacement were positively associated (p = 0.007), as were the ratio between Doppler E/e' and CMR E/E' (p = 0.01). CMR-determined normalized peak E (NE) and deceleration time (DT) were able to predict diastolic dysfunction (areas under the curve [AUCs] = 0.70 and 0.72, respectively). In addition, the lateral E/E' ratio showed good utility in identifying diastolic dysfunction (AUC = 0.80). Overall, echocardiography and CMR interobserver and intraobserver agreements were excellent (intraclass correlation coefficient range 0.72 - 0.97).

Conclusion:

3D modeling of standard cine CMR images was able to identify study subjects with reduced diastolic function and showed good reproducibility, suggesting a potential for a routine diastolic function assessment by CMR.

Fundamento:

A ressonância magnética cardíaca necessita de um método simples e robusto para a avaliação da função diastólica que pode ser feito com sequências protocolares de rotina.

Objetivo:

Desenvolver e validar a avaliação volumétrica da função diastólica através de um modelo tridimensional (3D) com utilização de imagens de ressonância magnética cardíaca (RMC) e comparar os resultados obtidos com este modelo com os obtidos por ecocardiografia.

Métodos:

Os participantes do estudo assinaram um termo de consentimento e foram incluídos se tivessem sido submetidos no mesmo dia tanto à ecocardiografia quanto à cine RMC com precessão livre no estado estacionário (steady-state free precession, SSFP). Pontos-guia foram utilizados no anel mitral septal e lateral para definir a velocidade de estiramento no início da diástole (E'), enquanto curvas de volume-tempo do modelo 3D foram utilizadas para avaliar os parâmetros de enchimento diastólico. Foram determinadas a correlação entre a RMC 3D e a ecocardiografia, além da acurácia da RMC em classificar o grau de função diastólica.

Resultados:

Ao todo, 102 sujeitos foram incluídos no estudo. A razão E/A pela RMC esteve positivamente associada com a razão E/A obtida pela ecocardiografia (r = 0,71, p < 0,0001). Estiveram positivamente associadas a velocidade de relaxamento diastólico inicial ao Doppler tecidual e a velocidade de relaxamento longitudinal de deslocamento do anel mitral lateral (p = 0,007), bem como a razão entre E/e' por Doppler e E/E' pela RMC (p = 0,01). A velocidade normalizada de pico de enchimento (EM) determinada pela RMC e o tempo de desaceleração (TD) foram capazes de predizer a disfunção diastólica (áreas sob a curva [AUCs] = 0,70 e 0,72, respectivamente). Além disso, a razão E/E' lateral mostrou boa utilidade para a identificação da disfunção diastólica (AUC = 0,80). No geral, a ecocardiografia e a RMC apresentaram excelente concordância interobservador e intraobservador (coeficiente de correlação intraclasse 0,72 - 0,97).

Conclusão:

Uma modelagem 3D de imagens padrões de cine RMC foi capaz de identificar os indivíduos do estudo com função diastólica reduzida e mostrou uma boa reprodutibilidade, sugerindo ter potencial na avaliação rotineira da função diastólica por RMC.

Obesity Is Associated With Progression of Atherosclerosis During Statin Treatment

Background

This study aimed to determine the relationship of statin therapy and cardiovascular risk factors to changes in atherosclerosis in the carotid artery.

Methods and Results

Carotid magnetic resonance imaging was used to evaluate 106 hyperlipidemic participants at baseline and after 12 months of 3‐hydroxy‐3‐methylglutaryl coenzyme A reductase inhibitor (statin) treatment. Multivariable logistic regression was used to determine factors associated with progression (change in carotid wall volume >0) or regression (change ≤0) of carotid atherosclerosis. Computed tomography coronary calcium scores were obtained at baseline for all participants. The median age was 65 years (interquartile range 60–69 years), and 63% of the participants were male. Body mass index >30, elevated C‐reactive protein, and hypertension were associated with increased carotid wall volume (obesity: odds ratio for progression 4.6, 95% CI 1.8–12.4, P<0.01; C‐reactive protein: odds ratio for progression 2.56, 95% CI 1.17–5.73, P=0.02; hypertension: odds ratio 2.4, 95% CI 1.1–5.3, P<0.05). Higher statin dose was associated with regression of carotid wall volume (P<0.05). In multivariable analysis, obesity remained associated with progression (P<0.01), whereas statin use remained associated with regression (P<0.05). Change in atheroma volume in obese participants was +4.8% versus −4.2% in nonobese participants (P<0.05) despite greater low‐density lipoprotein cholesterol reduction in obese participants.

Conclusions

In a population with hyperlipidemia, obese patients showed atheroma progression despite optimized statin therapy.

Clinical Trial Registration

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01212900.

Utility of Nontraditional Risk Markers in Atherosclerotic Cardiovascular Disease Risk Assessment

BACKGROUND

The improvement in discrimination gained by adding nontraditional cardiovascular risk markers cited in the 2013 American College of Cardiology/American Heart Association cholesterol guidelines to the atherosclerotic cardiovascular disease (ASCVD) risk estimator (pooled cohort equation [PCE]) is untested.

OBJECTIVES

This study assessed the predictive accuracy and improvement in reclassification gained by the addition of the coronary artery calcium (CAC) score, the ankle-brachial index (ABI), high-sensitivity C-reactive protein (hsCRP) levels, and family history (FH) of ASCVD to the PCE in participants of MESA (Multi-Ethnic Study of Atherosclerosis).

METHODS

The PCE was calibrated (cPCE) and used for this analysis. The Cox proportional hazards survival model, Harrell's C statistics, and net reclassification improvement analyses were used. ASCVD was defined as myocardial infarction, coronary heart disease-related death, or fatal or nonfatal stroke.

RESULTS

Of 6,814 MESA participants not prescribed statins at baseline, 5,185 had complete data and were included in this analysis. Their mean age was 61 years; 53.1% were women, 9.8% had diabetes, and 13.6% were current smokers. After 10 years of follow-up, 320 (6.2%) ASCVD events occurred. CAC score, ABI, and FH were independent predictors of ASCVD events in the multivariable Cox models. CAC score modestly improved the Harrell's C statistic (0.74 vs. 0.76; p = 0.04); ABI, hsCRP levels, and FH produced no improvement in Harrell's C statistic when added to the cPCE.

CONCLUSIONS

CAC score, ABI, and FH were independent predictors of ASCVD events. CAC score modestly improved the discriminative ability of the cPCE compared with other nontraditional risk markers.

Role of Coronary Artery Calcium Score of Zero and Other Negative Risk Markers for Cardiovascular Disease: The Multi-Ethnic Study of Atherosclerosis (MESA)

BACKGROUND

Limited attention has been paid to negative cardiovascular disease (CVD) risk markers despite their potential to improve medical decision making. We compared 13 negative risk markers using diagnostic likelihood ratios (DLRs), which model the change in risk for an individual after the result of an additional test.

METHODS AND RESULTS

We examined 6814 participants from the Multi-Ethnic Study of Atherosclerosis. Coronary artery calcium score of 0, carotid intima-media thickness <25th percentile, absence of carotid plaque, brachial flow-mediated dilation >5% change, ankle-brachial index >0.9 and <1.3, high-sensitivity C-reactive protein <2 mg/L, homocysteine <10 µmol/L, N-terminal pro-brain natriuretic peptide <100 pg/mL, no microalbuminuria, no family history of coronary heart disease (any/premature), absence of metabolic syndrome, and healthy lifestyle were compared for all and hard coronary heart disease and all CVD events over the 10-year follow-up. Models were adjusted for traditional CVD risk factors. Among all negative risk markers, coronary artery calcium score of 0 was the strongest, with an adjusted mean DLR of 0.41 (SD, 0.12) for all coronary heart disease and 0.54 (SD, 0.12) for CVD, followed by carotid intima-media thickness <25th percentile (DLR, 0.65 [SD, 0.04] and 0.75 [SD, 0.04], respectively). High-sensitivity C-reactive protein <2 mg/L and normal ankle-brachial index had DLRs >0.80. Among clinical features, absence of any family history of coronary heart disease was the strongest (DLRs, 0.76 [SD, 0.07] and 0.81 [SD, 0.06], respectively). Net reclassification improvement analyses yielded similar findings, with coronary artery calcium score of 0 resulting in the largest, most accurate downward risk reclassification.

CONCLUSIONS

Negative results of atherosclerosis-imaging tests, particularly coronary artery calcium score of 0, resulted in the greatest downward shift in estimated CVD risk. These results may help guide discussions on the identification of individuals less likely to receive net benefit from lifelong preventive pharmacotherapy.

Implications of Coronary Artery Calcium Testing Among Statin Candidates According to American College of Cardiology/American Heart Association Cholesterol Management Guidelines: MESA (Multi-Ethnic Study of Atherosclerosis)

BACKGROUND

The American College of Cardiology (ACC)/American Heart Association (AHA) cholesterol management guidelines have significantly broadened the scope of candidates eligible for statin therapy.

OBJECTIVES

This study evaluated the implications of the absence of coronary artery calcium (CAC) in reclassifying patients from a risk stratum in which statins are recommended to one in which they are not.

METHODS

MESA (Multi-Ethnic Study of Atherosclerosis) is a longitudinal study of 6,814 men and women 45 to 84 years of age without clinical atherosclerotic cardiovascular disease (ASCVD) risk at enrollment. We excluded 1,100 participants (16%) on lipid-lowering medication, 87 (1.3%) without low-density lipoprotein levels, 26 (0.4%) with missing risk factors for calculation of 10-year risk of ASCVD, 633 (9%) >75 years of age, and 209 (3%) with low-density lipoprotein <70 mg/dl from the analysis.

RESULTS

The study population consisted of 4,758 participants (age 59 ± 9 years; 47% males). A total of 247 (5.2%) ASCVD and 155 (3.3%) hard coronary heart disease events occurred over a median (interquartile range) follow-up of 10.3 (9.7 to 10.8) years. The new ACC/AHA guidelines recommended 2,377 (50%) MESA participants for moderate- to high-intensity statins; the majority (77%) was eligible because of a 10-year estimated ASCVD risk ≥7.5%. Of those recommended statins, 41% had CAC = 0 and had 5.2 ASCVD events/1,000 person-years. Among 589 participants (12%) considered for moderate-intensity statin, 338 (57%) had a CAC = 0, with an ASCVD event rate of 1.5 per 1,000 person-years. Of participants eligible (recommended or considered) for statins, 44% (1,316 of 2,966) had CAC = 0 at baseline and an observed 10-year ASCVD event rate of 4.2 per 1,000 person-years.

CONCLUSIONS

Significant ASCVD risk heterogeneity exists among those eligible for statins according to the new guidelines. The absence of CAC reclassifies approximately one-half of candidates as not eligible for statin therapy.

Can Antihypertensive Treatment Restore the Risk of Cardiovascular Disease to Ideal Levels?: The Coronary Artery Risk Development in Young Adults (CARDIA) Study and the Multi-Ethnic Study of Atherosclerosis (MESA)

Background

It is unclear whether antihypertensive treatment can restore cardiovascular disease risk to the risk level of persons with ideal blood pressure (BP) levels.

Methods and Results

Data from the Multi-Ethnic Study of Atherosclerosis (MESA) and the Coronary Artery Risk Development in Young Adults (CARDIA) study were analyzed. Outcomes were compared among participants without or with antihypertensive treatment at 3 BP levels: <120/<80 mm Hg, systolic BP 120 to 139 mm Hg or diastolic BP 80 to 89 mm Hg (120 to 129/≤80 mm Hg for participants with diabetes), and systolic BP ≥140 or diastolic BP ≥90 mm Hg (systolic BP ≥130 or diastolic BP ≥80 mm Hg for participants with diabetes). Among MESA participants aged ≥50 years at baseline, those with BP <120/<80 mm Hg on treatment had higher left ventricular mass index, prevalence of estimated glomerular filtration rate <60 mL/min per 1.73 m², prevalence of coronary calcium score >100, and twice the incident cardiovascular disease rate over 9.5 years of follow-up than those with BP <120/<80 mm Hg without treatment. In CARDIA at year 25, persons with BP <120/<80 mm Hg with treatment had much longer exposure to higher BP and higher risk of end-organ damage and subclinical atherosclerosis than those with BP <120/<80 mm Hg without treatment. An exploratory analysis suggested that when cumulative systolic BP was high (eg, >3000 mm Hg–years in 25 years), the increase in left ventricular mass index accelerated.

Conclusions

The data suggest that based on the current approach, antihypertensive treatment cannot restore cardiovascular disease risk to ideal levels. Emphasis should be placed on primordial prevention of BP increases to further reduce cardiovascular disease morbidity and mortality.

Utility of Nontraditional Risk Markers in Individuals Ineligible for Statin Therapy According to the 2013 American College of Cardiology/American Heart Association Cholesterol Guidelines

BACKGROUND

In the general population, the majority of cardiovascular events occur in people at the low to moderate end of population risk distribution. The 2013 American College of Cardiology/American Heart Association guideline on the treatment of blood cholesterol recommends consideration of statin therapy for adults with an estimated 10-year atherosclerotic cardiovascular disease (ASCVD) risk ≥7.5% based on traditional risk factors. Whether use of nontraditional risk markers can improve risk assessment in those below this threshold for statin therapy is unclear.

METHODS AND RESULTS

Using data from the Multi-Ethnic Study of Atherosclerosis (MESA), a population sample free of clinical CVD at baseline, we calibrated the Pooled Cohort Equations (cPCE). ASCVD was defined as myocardial infarction, coronary heart disease death, or fatal or nonfatal stroke. Adults with an initial cPCE <7.5% and elevated levels of additional risk markers (abnormal test) whose new calculated risk was ≥7.5% were considered statin eligible: low-density lipoprotein cholesterol ≥160 mg/dL; family history of ASCVD; high-sensitivity C-reactive protein ≥2 mg/dL; coronary artery calcium score ≥300 Agatston units or ≥75th percentile for age, sex, and ethnicity; and ankle-brachial index <0.9. We compared the absolute and relative ASCVD risks among those with versus without elevated posttest estimated risk. We calculated the number needed to screen to identify 1 person with abnormal test for each risk marker, defined as the number of participants with baseline cPCE risk <7.5% divided by the number with an abnormal test reclassified as statin eligible. Of 5185 participants not taking statins with complete data (age, 45-84 years), 4185 had a cPCE risk <7.5%. During 10 years of follow-up, 57% of the ASCVD events (183 of 320) occurred among adults with a cPCE risk <7.5%. When people with diabetes mellitus were excluded, the coronary artery calcium criterion reclassified 6.8% upward, with an event rate of 13.3%, absolute risk of 10%, relative risk of 4.0 (95% confidence interval [CI], 2.8-5.7), and number needed to screen of 14.7. The corresponding numbers for family history of ASCVD were 4.6%, 15.1%, 12%, 4.3 (95% CI, 3.0-6.4), and 21.8; for high-sensitivity C-reactive protein criteria, 2.6%, 10%, 6%, 2.6 (95% CI, 1.4-4.8), and 39.2; for ankle-brachial index criteria, 0.6%, 9%, 5%, 2.3 (95% CI, 0.6-8.6), and 176.5; and for low-density lipoprotein cholesterol criteria, 0.5%, 5%, 1%, 1.2 (95% CI, 0.2-8.4), and 193.3, respectively. Of the 3882 with <7.5% cPCE risk, 431 (11.1%) were reclassified to ≥7.5% (statin eligible) by at least 1 of the additional risk marker criteria.

CONCLUSIONS

In this generally low-risk population sample, a large proportion of ASCVD events occurred among adults with a 10-year cPCE risk <7.5%. We found that the coronary artery calcium score, high-sensitivity C-reactive protein, family history of ASCVD, and ankle-brachial index recommendations by the American College of Cardiology/American Heart Association cholesterol guidelines (Class IIB) identify small subgroups of asymptomatic population with a 10-year cPCE risk <7.5% but with observed ASCVD event rates >7.5% who may warrant statin therapy considerations.

Coronary Plaque Burden at Coronary CT Angiography in Asymptomatic Men and Women

Purpose To assess the relationship between total, calcified, and noncalcified coronary plaque burdens throughout the entire coronary vasculature at coronary computed tomographic (CT) angiography in relationship to cardiovascular risk factors in asymptomatic individuals with low-to-moderate risk. Materials and Methods This HIPAA-compliant study had institutional review board approval, and written informed consent was obtained. Two hundred two subjects were recruited to an ongoing prospective study designed to evaluate the effect of HMG-CoA reductase inhibitors on atherosclerosis. Eligible subjects were asymptomatic individuals older than 55 years who were eligible for statin therapy. Coronary CT angiography was performed by using a 320-detector row scanner. Coronary wall thickness and plaque were evaluated in all epicardial coronary arteries greater than 2 mm in diameter. Images were analyzed by using dedicated software involving an adaptive lumen attenuation algorithm. Total plaque index (calcified plus noncalcified plaque) was defined as plaque volume divided by vessel length. Multivariable regression analysis was performed to determine the relationship between risk factors and plaque indexes. Results The mean age of the subjects was 65.5 years ± 6.9 (standard deviation) (36% women), and the median coronary artery calcium (CAC) score was 73 (interquartile range, 1-434). The total coronary plaque index was higher in men than in women (42.06 mm(2) ± 9.22 vs 34.33 mm(2) ± 8.35; P < .001). In multivariable analysis controlling for all risk factors, total plaque index remained higher in men than in women (by 5.01 mm(2); P = .03) and in those with higher simvastatin doses (by 0.44 mm(2)/10 mg simvastatin dose equivalent; P = .02). Noncalcified plaque index was positively correlated with systolic blood pressure (β = 0.80 mm(2)/10 mm Hg; P = .03), diabetes (β = 4.47 mm(2); P = .03), and low-density lipoprotein (LDL) cholesterol level (β = 0.04 mm(2)/mg/dL; P = .02); the association with LDL cholesterol level remained significant (P = .02) after additional adjustment for the CAC score. Conclusion LDL cholesterol level, systolic blood pressure, and diabetes were associated with noncalcified plaque burden at coronary CT angiography in asymptomatic individuals with low-to-moderate risk. (©) RSNA, 2015 Online supplemental material is available for this article.

Abnormal Myocardial Function Is Related to Myocardial Steatosis and Diffuse Myocardial Fibrosis in HIV-Infected Adults

BACKGROUND

Impaired cardiac function persists in the era of effective human immunodeficiency virus (HIV) therapy, although the etiology is unclear. We used magnetic resonance imaging (MRI) to measure intramyocardial lipid levels and fibrosis as possible contributors to HIV-associated myocardial dysfunction.

METHODS

A cross-sectional study of 95 HIV-infected and 30 matched-healthy adults, without known cardiovascular disease (CVD) was completed. Intramyocardial lipid levels, myocardial fibrosis, and cardiac function (measured on the basis of strain) were quantified by MRI.

RESULTS

Systolic function was significantly decreased in HIV-infected subjects as compared to controls (mean radial strain [±SD], 21.7 ± 8.6% vs 30.5 ± 14.2%; P = .004). Intramyocardial lipid level and fibrosis index were both increased in HIV-infected subjects as compared to controls (P ≤ .04 for both) and correlated with the degree of myocardial dysfunction measured by strain parameters. Intramyocardial lipid levels correlated positively with antiretroviral therapy duration and visceral adiposity. Further, impaired myocardial function was strongly correlated with increased monocyte chemoattractant protein 1 levels (r = 0.396, P = .0002) and lipopolysaccharide binding protein levels (r = 0.25, P = .02).

CONCLUSIONS

HIV-infected adults have reduced myocardial function as compared to controls in the absence of known CVD. Decreased cardiac function was associated with abnormal myocardial tissue composition characterized by increased lipid levels and diffuse myocardial fibrosis. Metabolic alterations related to antiretroviral therapy and chronic inflammation may be important targets for optimizing long-term cardiovascular health in HIV-infected individuals.

Lipoprotein particles and incident type 2 diabetes in the multi-ethnic study of atherosclerosis

OBJECTIVE

In the Multi-Ethnic Study of Atherosclerosis (MESA), we evaluated associations of baseline levels of a lipoprotein-based insulin resistance (IR) index (LP-IR), IR-related lipoprotein particles, mean particle sizes, and lipids, with incident type 2 diabetes, independent of confounders, glucose, insulin, and HOMA-IR.

RESEARCH DESIGN AND METHODS

Among 5,314 adults aged 45-84 years without baseline diabetes or cardiovascular disease, 656 cases of diabetes were identified during a mean follow-up of 7.7 years. Lipoprotein particle concentrations, size, and LP-IR were determined by nuclear magnetic resonance spectroscopy of stored baseline plasma. Potential effect modification, by race/ethnicity, sex, baseline use of lipid-lowering medications or hormone therapy, or glucose strata (<90, 90-99, and ≥ 100 mg/dL), was also evaluated.

RESULTS

Higher levels of LP-IR, large VLDL particles (VLDL-P), small LDL particles, triglycerides (TG), and TG-to-HDL cholesterol (HDL-C) ratio and lower levels of large HDL particles, smaller HDL and LDL size, and larger VLDL size were significantly associated with incident diabetes adjusted for confounders and glucose or insulin. These also were similar by race/ethnicity, sex, and treatment group. Associations were similar for LP-IR, large VLDL-P, mean VLDL size, TG, and TG-to-HDL-C ratio; they persisted for LP-IR, large VLDL-P, or mean VLDL size adjusted for HOMA-IR or TG-to-HDL-C ratio and glucose but not for the TG-to-HDL-C ratio adjusted for LP-IR or for HOMA-IR or insulin if adjusted for LP-IR and glucose.

CONCLUSIONS

Among ethnically diverse men and women, LP-IR, large VLDL-P, large VLDL size, TG, and TG-to-HDL-C ratio were associated with incident diabetes independent of established risk factors, glucose, insulin, or HOMA-IR, as well as the use of lipid-lowering medications or hormone therapy.

Association of parity with carotid diameter and distensibility: multi-ethnic study of atherosclerosis

Pregnancy and childbirth are associated with hemodynamic changes and vascular remodeling. It is not known whether parity is associated with later adverse vascular properties such as larger arterial diameter, wall thickness, and lower distensibility. We used baseline data from 3283 women free of cardiovascular disease aged 45 to 84 years enrolled in the population-based Multi-Ethnic Study of Atherosclerosis. Participants self-reported parity status. Ultrasound-derived carotid artery lumen diameters and brachial artery blood pressures were measured at peak-systole and end-diastole. Common carotid intima-media thickness was also measured. Regression models to determine the association of carotid distensibility coefficient, lumen diameter, and carotid intima-media thickness with parity were adjusted for age, race, height, weight, diabetes mellitus, current smoking, blood pressure medication use, and total and high-density lipoprotein cholesterol levels. The prevalence of nulliparity was 18%. In adjusted models, carotid distensibility coefficient was 0.09×10−5 Pa−1 lower (P=0.009) in parous versus nulliparous women. Among parous women, there was a nonlinear association with the greatest carotid distensibility coefficient seen in women with 2 live births and significantly lower distensibility seen in primiparas (P=0.04) or with higher parity >2 (P=0.005). No such pattern of association with parity was found for lumen diameter or carotid intima-media thickness. Parity is associated with lower carotid artery distensibility, suggesting arterial remodeling that lasts beyond childbirth. These long-term effects on the vasculature may explain the association of parity with cardiovascular events later in life.

Assessment of atherosclerosis in chronic granulomatous disease

BACKGROUND

Patients with chronic granulomatous disease (CGD) experience immunodeficiency because of defects in the phagocyte NADPH oxidase and the concomitant reduction in reactive oxygen intermediates. This may result in a reduction in atherosclerotic injury.

METHODS AND RESULTS

We prospectively assessed the prevalence of cardiovascular risk factors, biomarkers of inflammation and neutrophil activation, and the presence of magnetic resonance imaging and computed tomography quantified subclinical atherosclerosis in the carotid and coronary arteries of 41 patients with CGD and 25 healthy controls in the same age range. Univariable and multivariable associations among risk factors, inflammatory markers, and atherosclerosis burden were assessed. Patients with CGD had significant elevations in traditional risk factors and inflammatory markers compared with control subjects, including hypertension, high-sensitivity C-reactive protein, oxidized low-density lipoprotein, and low high-density lipoprotein. Despite this, patients with CGD had a 22% lower internal carotid artery wall volume compared with control subjects (361.3±76.4 mm(3) versus 463.5±104.7 mm(3); P<0.001). This difference was comparable in p47(phox)- and gp91(phox)-deficient subtypes of CGD and independent of risk factors in multivariate regression analysis. In contrast, the prevalence of coronary arterial calcification was similar between patients with CGD and control subjects (14.6%, CGD; 6.3%, controls; P=0.39).

CONCLUSIONS

The observation by magnetic resonance imaging and computerized tomography of reduced carotid but not coronary artery atherosclerosis in patients with CGD despite the high prevalence of traditional risk factors raises questions about the role of NADPH oxidase in the pathogenesis of clinically significant atherosclerosis. Additional high-resolution studies in multiple vascular beds are required to address the therapeutic potential of NADPH oxidase inhibition in cardiovascular diseases.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov. Unique identifier: NCT01063309.

Association of albumin-creatinine ratio and cystatin C with change in ankle-brachial index: the Multi-Ethnic Study of Atherosclerosis (MESA)

BACKGROUND

Low ankle-brachial index (ABI) is a reflection of atherosclerotic disease, and high ABI is an indicator of calcified vessels. The associations of albuminuria and cystatin C level with incidence of either low or high ABI are unknown.

STUDY DESIGN

Prospective longitudinal cohort study.

SETTING & PARTICIPANTS

MESA (Multi-Ethnic Study of Atherosclerosis) enrolled community-dwelling adults (N=6,814) aged 45-84 years who were free of clinical cardiovascular disease at baseline.

PREDICTORS

Baseline albumin-creatinine ratio (ACR) and serum cystatin C level.

OUTCOMES

Development of low (<0.90), and high (>1.40) ABI using multinomial regression among persons with ABI of 0.90-1.40 at baseline.

RESULTS

During 9.8 years of follow-up, 221 and 89 participants progressed to low and high ABIs, respectively. Baseline ACR and cystatin C level were higher among progressors compared with nonprogressors. In multivariable analyses, doubling of ACR was associated with increased risk of progression to low (OR, 1.08; 95% CI, 0.99-1.20) and high (OR, 1.16; 95% CI, 1.01-1.32) ABIs. Compared to the lowest quintile, the highest quintile of ACR had a significantly increased risk of progression to low (OR, 1.79; 95% CI, 1.03-3.12) and high (OR, 2.76; 95% CI, 1.32-5.77) ABIs. Higher cystatin C levels were associated with progression to low (OR per 1-SD greater, 1.12; 95% CI, 1.00-1.26) but not high (OR per 1-SD greater, 1.01; 95% CI, 0.81-1.25) ABI, but the highest quintile of cystatin C was not associated independently with either outcome.

LIMITATIONS

Single measure of albuminuria and low number of progressors to high ABI.

CONCLUSIONS

In adults free of clinical cardiovascular disease, albuminuria was a strong independent risk factor for the development of both high and low ABIs, important and different measures of peripheral artery disease.

Mediation of cardiovascular risk factor effects through subclinical vascular disease: the Multi-Ethnic Study of Atherosclerosis

OBJECTIVE

It is unclear to what extent subclinical cardiovascular disease (CVD) such as coronary artery calcium (CAC), carotid intima-media thickness (CIMT), and brachial flow-mediated dilation (FMD) are mediators of the known associations between traditional cardiovascular risk factors and incident CVD events. We assessed the portion of the effects of risk factors on incident CVD events that are mediated through CAC, CIMT, and FMD.

APPROACH AND RESULTS

Six thousand three hundred fifty-five of 6814 Multi-Ethnic Study of Atherosclerosis participants were included. Nonlinear implementation of structural equation modeling (STATA mediation package) was used to assess whether CAC, CIMT, or FMD are mediators of the association between traditional risk factors and incident CVD event. Mean age was 62 years, with 47% men, 12% diabetics, and 13% current smokers. After a mean follow-up of 7.5 years, there were 539 CVD adjudicated events. CAC showed the highest mediation while FMD showed the least. Age had the highest percent of total effect mediated via CAC for CVD outcomes, whereas current cigarette smoking had the least percent of total effect mediated via CAC (percent [95% confidence interval]: 80.2 [58.8-126.7] versus 10.6 [6.1-38.5], respectively). Body mass index showed the highest percent of total effect mediated via CIMT (17.7 [11.6-38.9]); only a negligible amount of the association between traditional risk factors and CVD was mediated via FMD.

CONCLUSIONS

Many of the risk factors for incident CVD (other than age, sex, and body mass index) showed a modest level of mediation via CAC, CIMT, and FMD, suggesting that current subclinical CVD markers may not be optimal intermediaries for gauging upstream risk factor modification.

A framework to measure myocardial extracellular volume fraction using dual-phase low dose CT images

PURPOSE

Myocardial extracellular volume fraction (ECVF) is a surrogate imaging biomarker of diffuse myocardial fibrosis, a hallmark of pathologic ventricular remodeling. Low dose cardiac CT is emerging as a promising modality to detect diffuse interstitial myocardial fibrosis due to its fast acquisition and low radiation; however, the insufficient contrast in the low dose CT images poses great challenge to measure ECVF from the image.

METHODS

To deal with this difficulty, the authors present a complete ECVF measurement framework including a point-guided myocardial modeling, a deformable model-based myocardium segmentation, nonrigid registration of pre- and post-CT, and ECVF calculation.

RESULTS

The proposed method was evaluated on 20 patients by two observers. Compared to the manually delineated reference segmentations, the accuracy of our segmentation in terms of true positive volume fraction (TPVF), false positive volume fraction (FPVF), and average surface distance (ASD), were 92.18% ± 3.52%, 0.31% ± 0.10%, 0.69 ± 0.14 mm, respectively. The interobserver variability measured by concordance correlation coefficient regarding TPVF, FPVF, and ASD were 0.95, 0.90, 0.94, respectively, demonstrating excellent agreement. Bland-Altman method showed 95% limits of agreement between ECVF at CT and ECVF at MR.

CONCLUSIONS

The proposed framework demonstrates its efficiency, accuracy, and noninvasiveness in ECVF measurement and dramatically advances the ECVF at cardiac CT toward its clinical use.

Coronary artery plaque volume and obesity in patients with diabetes: the factor-64 study

PURPOSE

To determine the relationship between coronary plaque detected with coronary computed tomographic (CT) angiography and clinical parameters and cardiovascular risk factors in asymptomatic patients with diabetes.

MATERIALS AND METHODS

All patients signed institutional review board-approved informed consent forms before enrollment. Two hundred twenty-four asymptomatic diabetic patients (121 men; mean patient age, 61.8 years; mean duration of diabetes, 10.4 years) underwent coronary CT angiography. Total coronary artery wall volume in all three vessels was measured by using semiautomated software. The coronary plaque volume index (PVI) was determined by dividing the wall volume by the coronary length. The relationship between the PVI and cardiovascular risk factors was determined with multivariable analysis.

RESULTS

The mean PVI (±standard deviation) was 11.2 mm(2) ± 2.7. The mean coronary artery calcium (CAC) score (determined with the Agatston method) was 382; 67% of total plaque was noncalcified. The PVI was related to age (standardized β = 0.32, P < .001), male sex (standardized β = 0.36, P < .001), body mass index (BMI) (standardized β = 0.26, P < .001), and duration of diabetes (standardized β = 0.14, P = .03). A greater percentage of soft plaque was present in younger individuals with a shorter disease duration (P = .02). The soft plaque percentage was directly related to BMI (P = .002). Patients with discrepancies between CAC score and PVI rank quartiles had a higher percentage of soft and fibrous plaque (18.7% ± 3.3 vs 17.4% ± 3.5 [P = .008] and 52.2% ± 7.2 vs 47.2% ± 8.8 [P < .0001], respectively).

CONCLUSION

In asymptomatic diabetic patients, BMI was the primary modifiable risk factor that was associated with total and soft coronary plaque as assessed with coronary CT angiography.

Atrial septal angulation varies widely in patients undergoing pulmonary vein isolation

PURPOSE

Transseptal puncture (TSP) allows left atrial access for curative procedures. Intracardiac echocardiography (ICE) provides direct visualization of the interatrial septum (IAS), but adds time and expense. We reviewed 100 cardiac multidetector computed tomography (MDCT) scans of patients undergoing AF ablation to determine if the angulation and orientation of the IAS are conserved or variable. Significant variability may suggest a potential role for direct visualization of the IAS during TSP.

METHODS

We reviewed 100 MDCT scans obtained prior to AF ablation. The IAS plane at the fossa ovalis was identified in axial and coronal images. We measured the angle of the septum relative to an orthogonal plane. Optimal needle orientation was defined as perpendicular to the fossa ovalis.

RESULTS

The mean axial plane angle was -60.6 ± 10.6°; range, -29.5° to -88.7°). The mean coronal plane angle was 142.6 ± 9.1°; range, 115° to 162°). The axial angle corresponded to variation in the "clock-face" orientation of the needle during puncture, and was calculated between 4 and 6 o'clock. Coronal plane angulation corresponds to the curvature of the needle tip, which varied by 47°. We found no association between patient characteristics and IAS angle.

CONCLUSION

The septal orientation in the axial plane varied widely and was not predicted by clinical variables such as atrial size or prior valve surgery. The high degree of interpatient variability observed suggests that direct visualization of the septum may be helpful in the performance of TSP.

Impact of coronary artery calcium on coronary heart disease events in individuals at the extremes of traditional risk factor burden: the Multi-Ethnic Study of Atherosclerosis

AIMS

We sought to evaluate the impact of coronary artery calcium (CAC) in individuals at the extremes of risk factor (RF) burden.

METHODS AND RESULTS

6698 individuals from the Multi-Ethnic Study of Atherosclerosis (MESA) were followed for coronary heart disease (CHD) events over mean 7.1 ± 1 years. Annualized CHD event rates were compared among each RF category (0, 1, 2, or ≥3) after stratification by CAC score (0, 1-100, 101-300, and >300). The following traditional modifiable RFs were considered: cigarette smoking, LDL cholesterol ≥3.4 mmol/L, low HDL cholesterol, hypertension, and diabetes. There were 1067 subjects (16%) with 0 RFs, whereas 1205 (18%) had ≥3 RFs. Among individuals with 0 RFs, 68% had CAC 0, whereas 12 and 5% had CAC >100 and >300, respectively. Among individuals with ≥3 RFs, 35% had CAC 0, whereas 34 and 19% had CAC >100 and >300, respectively. Overall, 339 (5.1%) CHD events occurred. Individuals with 0 RFs and CAC >300 had an event rate 3.5 times higher than individuals with ≥3 RFs and CAC 0 (10.9/1000 vs. 3.1/1000 person-years). Similar results were seen across categories of Framingham risk score.

CONCLUSION

Among individuals at the extremes of RF burden, the distribution of CAC is heterogeneous. The presence of a high CAC burden, even among individuals without RFs, is associated with an elevated event rate, whereas the absence of CAC, even among those with many RF, is associated with a low event rate. Coronary artery calcium has the potential to further risk stratify asymptomatic individuals at the extremes of RF burden.

Point-guided modeling and segmentation of myocardium for low dose cardiac CT images

Cardiac CT is emerging as a preferable modality to detect myocardial stress/rest perfusion; however the insufficient contrast of myocardium on CT image makes its segmentation difficult. In this paper, we present a point-guided modeling and deformable model-based segmentation method. This method first builds a triangular surface model of myocardium through Bézier contour fitting based on a few points selected by clinicians. Then, a deformable model-based segmentation method is developed to refine the segmentation result. The experiments on 8 cases show the accuracy of the segmentation in terms of true positive volume fraction, false positive volume fractions, and average surface distance can reach 91.0%, 0.3%, and 0.6mm, respectively. The comparison between the proposed method and a graph cut-based method is performed. The results demonstrate that this method is effective in improving the accuracy further.

Interpretation of the coronary artery calcium score in combination with conventional cardiovascular risk factors: the Multi-Ethnic Study of Atherosclerosis (MESA)

BACKGROUND

The coronary artery calcium (CAC) score predicts coronary heart disease (CHD) events, but methods for interpreting the score in combination with conventional CHD risk factors have not been established.

METHODS AND RESULTS

We analyzed CAC scores and CHD risk factor measurements from 6757 black, Chinese, Hispanic, and white men and women aged 45 to 84 years in the Multi-Ethnic Study of Atherosclerosis (MESA). CAC was associated with age, sex, race/ethnicity, and all conventional CHD risk factors. Multivariable models using these factors predicted the presence of CAC (C statistic=0.789) and degree of elevation (16% of variation explained) and can be used to update a "pretest" CHD risk estimate, such as the 10-year Framingham Risk Score, that is based on an individual's conventional risk factors. In scenarios in which a high CAC score is expected, a moderately elevated CAC score of 50 is reassuring (eg, reducing risk from 10% to 6% in a healthy older white man), but when a low/zero CAC score is expected, even with identical pretest CHD risk, the same CAC score of 50 may be alarmingly high (eg, increasing risk from 10% to 20% in a middle-aged black woman with multiple risk factors). Both the magnitude and direction of the shift in risk varied markedly with pretest CHD risk and with the pattern of risk factors.

CONCLUSIONS

Knowledge of what CAC score to expect for an individual patient, based on their conventional risk factors, may help clinicians decide when to order a CAC test and how to interpret the results.

MRI-measured regression of carotid atherosclerosis induced by statins with and without niacin in a randomised controlled trial: the NIA plaque study

OBJECTIVE

To evaluate the benefit of niacin in addition to statin therapy on plaque regression among older individuals with established atherosclerosis.

DESIGN

Randomised, controlled, double-blind clinical trial.

SETTING

University outpatient center.

PATIENTS

145 patients older than 65 years, half of them older than 75 years of age, with established atherosclerosis were enrolled.

INTERVENTIONS

Participants received either extended release niacin (1500 mg daily) or placebo in addition to statin therapy to reach their National Cholesterol Education Program-defined low density lipoprotein (LDL) cholesterol target.

MAIN OUTCOME MEASURES

The primary endpoint was reduction in the wall volume of the internal carotid artery (ICA) measured by MRI.

RESULTS

After 18 months, high density lipoprotein cholesterol was higher with statins plus niacin compared with statins alone (1.6 ± 0.4 vs 1.4 ± 0.4 mmol/L p<0.001). Both groups had significant decreases in the main outcome measure of ICA wall volume, which regressed at 0.5%/month (SEM 0.2, p=0.004) in the statins plus placebo group and at 0.7%/month in the statins plus niacin group (SEM 0.2, p<0.001). There was no difference in the rate of regression between groups (p=0.49).

CONCLUSIONS

Treatment with statin therapy to presently recommended LDL levels, with or without niacin, resulted in significant atherosclerosis reduction.

Low-risk lifestyle, coronary calcium, cardiovascular events, and mortality: results from MESA

Unhealthy lifestyle habits are a major contributor to coronary artery disease. The purpose of the present study was to investigate the associations of smoking, weight maintenance, physical activity, and diet with coronary calcium, cardiovascular events, and mortality. US participants who were 44-84 years of age (n = 6,229) were followed in the Multi-Ethnic Study of Atherosclerosis from 2000 to 2010. A lifestyle score ranging from 0 to 4 was created using diet, exercise, body mass index, and smoking status. Coronary calcium was measured at baseline and a mean of 3.1 (standard deviation, 1.3) years later to assess calcium progression. Participants who experienced coronary events or died were followed for a median of 7.6 (standard deviation, 1.5) years. Participants with lifestyle scores of 1, 2, 3, and 4 were found to have mean adjusted annual calcium progressions that were 3.5 (95% confidence interval (CI): 0.0, 7.0), 4.2 (95% CI: 0.6, 7.9), 6.8 (95% CI: 2.0, 11.5), and 11.1 (95% CI: 2.2, 20.1) points per year slower, respectively, relative to the reference group (P = 0.003). Unadjusted hazard ratios for death by lifestyle score were as follows: for a score of 1, the hazard ratio was 0.79 (95% CI: 0.61, 1.03); for a score of 2, the hazard ratio was 0.61 (95% CI: 0.46, 0.81); for a score of 3, the hazard ratio was 0.49 (95% CI: 0.32, 0.75); and for a score of 4, the hazard ratio was 0.19 (95% CI: 0.05, 0.75) (P < 0.001 by log-rank test). In conclusion, a combination of regular exercise, healthy diet, smoking avoidance, and weight maintenance was associated with lower coronary calcium incidence, slower calcium progression, and lower all-cause mortality over 7.6 years.

Using imputed pre-treatment cholesterol in a propensity score model to reduce confounding by indication: results from the multi-ethnic study of atherosclerosis

Background

Studying the effects of medications on endpoints in an observational setting is an important yet challenging problem due to confounding by indication. The purpose of this study is to describe methodology for estimating such effects while including prevalent medication users. These techniques are illustrated in models relating statin use to cardiovascular disease (CVD) in a large multi-ethnic cohort study.

Methods

The Multi-Ethnic Study of Atherosclerosis (MESA) includes 6814 participants aged 45-84 years free of CVD. Confounding by indication was mitigated using a two step approach: First, the untreated values of cholesterol were treated as missing data and the values imputed as a function of the observed treated value, dose and type of medication, and participant characteristics. Second, we construct a propensity-score modeling the probability of medication initiation as a function of measured covariates and estimated pre-treatment cholesterol value. The effect of statins on CVD endpoints were assessed using weighted Cox proportional hazard models using inverse probability weights based on the propensity score.

Results

Based on a meta-analysis of randomized controlled trials (RCT) statins are associated with a reduced risk of CVD (relative risk ratio = 0.73, 95% CI: 0.70, 0.77). In an unweighted Cox model adjusting for traditional risk factors we observed little association of statins with CVD (hazard ratio (HR) = 0.97, 95% CI: 0.60, 1.59). Using weights based on a propensity model for statins that did not include the estimated pre-treatment cholesterol we observed a slight protective association (HR = 0.92, 95% CI: 0.54-1.57). Results were similar using a new-user design where prevalent users of statins are excluded (HR = 0.91, 95% CI: 0.45-1.80). Using weights based on a propensity model with estimated pre-treatment cholesterol the effects of statins (HR = 0.74, 95% CI: 0.38, 1.42) were consistent with the RCT literature.

Conclusions

The imputation of pre-treated cholesterol levels for participants on medication at baseline in conjunction with a propensity score yielded estimates that were consistent with the RCT literature. These techniques could be useful in any example where inclusion of participants exposed at baseline in the analysis is desirable, and reasonable estimates of pre-exposure biomarker values can be estimated.

Statin therapy and levels of hemostatic factors in a healthy population: the Multi-Ethnic Study of Atherosclerosis

BACKGROUND

HMG-CoA reductase inhibitors (statins) reduce the risk of venous thromboembolism (VTE) in healthy people. Statins reduce levels of inflammation biomarkers; however, the mechanism for the reduction in VTE risk is unknown.

AIM

In a large cohort of healthy people, we studied associations of statin use with plasma hemostatic factors related to VTE risk.

METHODS

Cross-sectional analyses were performed in the Multi-Ethnic Study of Atherosclerosis (MESA), a cohort study of 6814 healthy men and women aged 45-84 years, free of clinical cardiovascular disease at baseline; 1001 were using statins at baseline. Twenty-three warfarin users were excluded. Age, race and sex-adjusted mean hemostatic factor levels were compared between statin users and non-users, and multivariable linear regression models were used to assess associations of statin use with hemostatic factors, adjusted for age, race/ethnicity, education, income, aspirin use, hormone replacement therapy (in women), and major cardiovascular risk factors.

RESULTS

Participants using statins had lower adjusted levels of D-dimer (- 9%), C-reactive protein (- 21%) and factor VIII (- 3%) than non-users (P < 0.05). Homocysteine and von Willebrand factor levels were non-significantly lower with statin use. Higher fibrinogen (2%) and plasminogen activator inhibitor-1 (22%) levels were observed among statin users than among non-users (P < 0.05). Further adjustment for LDL and triglyceride levels did not attenuate the observed differences in these factors with statin use.

CONCLUSIONS

Findings of lower D-dimer, FVIII and C-reactive protein levels with statin use suggest hypotheses for mechanisms whereby statins might lower VTE risk. A prospective study or clinical trial linking these biochemical differences to VTE outcomes in statin users and non-users is warranted.

Competing cardiovascular outcomes associated with subclinical atherosclerosis (from the Multi-Ethnic Study of Atherosclerosis)

Subclinical atherosclerosis measured by coronary artery calcium (CAC) is associated with increased risk for multiple cardiovascular disease (CVD) outcomes and non-CVD death simultaneously. The aim of this study was to determine the competing risks of specific CVD events and non-CVD death associated with varying burdens of subclinical atherosclerosis. A total of 3,095 men and 3,486 women from the Multi-Ethnic Study of Atherosclerosis (MESA), aged 45 to 84 years, from 4 ethnic groups were included. Participants were stratified by CAC score (0, 1 to 99, and ≥100). Competing Cox models were used to determine competing cumulative incidences and hazard ratios within a group (e.g., those with CAC scores ≥100) and hazard ratios for specific events between groups (e.g., CAC score ≥100 vs 0). Risks were compared for specific CVD events and also against non-CVD death. In women, during a mean follow-up period of 7.1 years, the hazard ratios for any CVD event compared with a non-CVD death occurring first for CAC score 0 and CAC score ≥100 were 1.40 (95% confidence interval 0.97 to 2.04) and 3.07 (95% confidence interval 2.02 to 4.67), respectively. Coronary heart disease was the most common first CVD event type at all levels of CAC, and coronary heart disease rates were 9.5% versus 1.6% (hazard ratio 6.24, 95% confidence interval 3.99 to 9.75) for women with CAC scores ≥100 compared with CAC scores of 0. Similar results were observed in men. In conclusion, at all levels of CAC, coronary heart disease was the most common first CVD event, and this analysis represents a novel approach to understanding the temporal sequence of cardiovascular events associated with atherosclerosis.

Association of lipids with incident heart failure among adults with and without diabetes mellitus: Multiethnic Study of Atherosclerosis

BACKGROUND

Dyslipidemia is a known risk factor for coronary disease, but its role in heart failure (HF) development is less well-defined.

METHODS AND RESULTS

We included 5688 participants, aged 45 to 84 years, without clinical cardiovascular disease, and not receiving lipid-lowering medications at baseline, from the Multiethnic Study of Atherosclerosis. Cox-proportional hazards models were used to evaluate associations of triglyceride, total cholesterol/high-density lipoprotein-cholesterol (HDL-C) ratio, HDL-C, and non HDL-C with incident HF. We investigated for effect-modification by diabetes mellitus status and sex. During a median follow-up of 8.5 years, there were 152 incident HF cases. There were no interactions by sex. We observed significant interactions between triglyceride and diabetes mellitus (P(interaction)<0.05). We stratified our analyses by diabetes mellitus status. In participants with diabetes, the hazard ratios were 2.03 (0.97-4.27) and 1.68 (1.18-2.38) for high triglyceride and log of triglyceride, respectively, after adjusting for confounders, comorbidities, and diabetes mellitus severity/treatment. The association of high triglyceride with incident HF was attenuated by interim myocardial infarction. The hazard ratios were greatest in participants with diabetes who also had high triglyceride, low HDL-C, or high total cholesterol/HDL-C ratio (3.59 [2.03-6.33], 3.62 [2.06-6.36], and 3.54 [1.87-6.70], respectively). Lipid measures were not associated with incident HF in individuals without diabetes.

CONCLUSIONS

The risk of incident HF is greater in individuals with diabetes mellitus who also have high triglyceride, low HDL-C, or high total cholesterol/HDL-C ratio. The association of high triglyceride with incident HF is partly mediated by myocardial infarction.

3.0-T whole-heart coronary magnetic resonance angiography: comparison of gadobenate dimeglumine and gadofosveset trisodium

Gadolinium enhanced coronary magnetic resonance angiography (MRA) at 3 T appears to be superior to non-contrast methods. Gadofosveset is an intravascular contrast agent that may be well suited to this application. The purpose of this study was to perform an intra-individual comparison of gadofosveset and gadobenate for coronary MRA at 3 T. In this prospective randomized study, 22 study subjects [8 (36%) male; 27.9 ± 6 years; BMI = 22.8 ± 2 kg/m(2)] underwent two studies using a contrast-enhanced inversion recovery three-dimensional fast low angle shot MRA at 3 T. The order of contrast agent administration was varied randomly, separated by an average of 30 ± 5 days, using either gadobenate dimeglumine (Gd-BOPTA; Bracco, 0.1 mmol/Kg) or gadofosveset trisodium (MS-325; Lantheus Med, 0.03 mmol/Kg). Acquisition time, signal-to-noise ratio (SNR) of coronary vessels and contrast-to-noise ratio (CNR) were evaluated. Of 308 coronary arteries and veins segment analyzed, overall SNR of coronary arteries and veins segments were not different for the two contrast agents (132 ± 79 for gadofosveset vs. 135 ± 78 for gadobenate, p = 0.69). Coronary artery CNR was greater for gadofosveset in comparison to gadobenate (73.5 ± 46.9 vs. 59.3 ± 75.7 respectively, p = 0.03). Gadofosveset-enhanced MRA images displayed better image quality than gadobenate-enhanced MRA images (2.77 ± 0.61 for gadofosveset vs. 2.11 ± 0.51, p < .001). Inter- and intra-reader variability was excellent (ICC > 0.90) for both contrast agents. Gadofosveset trisodium appears to show slightly better performance for coronary MRA at 3 T compared to gadobenate.

Does elevated plasma triglyceride level independently predict impaired fasting glucose?: the Multi-Ethnic Study of Atherosclerosis (MESA)

OBJECTIVE

Elevated plasma triglycerides (TGs) have been included in diabetes risk prediction models. This study examined whether elevated TGs predict risk for impaired fasting glucose (IFG).

RESEARCH DESIGN AND METHODS

This study used the baseline and longitudinal follow-up data from the Multi-Ethnic Study of Atherosclerosis (MESA). The analysis included non-Hispanic whites, African Americans, Hispanics, and Chinese Americans 45-84 years of age who had fasting glucose <100 mg/dL at baseline and who did not have clinically evident cardiovascular disease or diabetes. Cox proportional regression models were used to examine the association of elevated TGs with incidence of IFG adjusting for central obesity, low HDL cholesterol, elevated blood pressure, baseline fasting glucose, and BMI. Area under the receiver operating characteristic curve (AUC), sensitivity, and specificity of elevated TGs in predicting IFG were calculated.

RESULTS

The incidence rate of developing IFG was 59.1 per 1,000 person-years during the median 4.75 years of follow-up. African Americans and Hispanics had a higher incidence rate of IFG compared with non-Hispanic whites among people with normal TG concentrations. Elevated TGs (>150 mg/dL) at baseline were independently associated with the incidence of IFG with an adjusted hazard ratio of 1.19 (95% CI 1.04-1.37). However, its predictive value for identifying people at risk for IFG was poor, with <57% AUC. Interactions of elevated TGs with race/ethnicity in predicting IFG were not statistically significant.

CONCLUSIONS

Elevated TGs were moderately associated with risk for IFG, and it was a poor risk prediction tool for IFG.

Prediction and classification of cardiovascular disease risk in older adults with diabetes

AIMS/HYPOTHESIS

We sought to derive and validate a cardiovascular disease (CVD) prediction algorithm for older adults with diabetes, and evaluate the incremental benefit of adding novel circulating biomarkers and measures of subclinical atherosclerosis.

METHODS

As part of the Cardiovascular Health Study (CHS), a population-based cohort of adults aged ≥65 years, we examined the 10 year risk of myocardial infarction, stroke and cardiovascular death in 782 older adults with diabetes, in whom 265 events occurred. We validated predictive models in 843 adults with diabetes, who were followed for 7 years in a second cohort, the Multi-Ethnic Study of Atherosclerosis (MESA); here 71 events occurred.

RESULTS

The best fitting standard model included age, smoking, systolic blood pressure, total and HDL-cholesterol, creatinine and the use of glucose-lowering agents; however, this model had a C statistic of 0.64 and poorly classified risk in men. Novel biomarkers did not improve discrimination or classification. The addition of ankle-brachial index, electrocardiographic left ventricular hypertrophy and internal carotid intima-media thickness modestly improved discrimination (C statistic 0.68; p = 0.002) and classification (net reclassification improvement [NRI] 0.12; p = 0.01), mainly in those remaining free of CVD. Results were qualitatively similar in the MESA, with a change in C statistic from 0.65 to 0.68 and an NRI of 0.09 upon inclusion of subclinical disease measures.

CONCLUSIONS/INTERPRETATION

Standard clinical risk factors and novel biomarkers poorly discriminate and classify CVD risk in older adults with diabetes. The inclusion of subclinical atherosclerotic measures modestly improves these features, but to develop more robust risk prediction, a better understanding of the pathophysiology and determinants of CVD in this patient group is needed.

Differentiation of myocardial scar from potential pitfalls and artefacts in delayed enhancement MRI

Delayed enhancement cardiac magnetic resonance (DE-CMR) imaging is used increasingly to identify and quantify focal myocardial scar. Our objective is to describe factors used in the interpretation of DE-CMR images and to highlight potential pitfalls and artefacts that mimic myocardial scar. Inversion recovery gradient recalled echo sequence is commonly accepted as the standard of reference for DE-CMR. There are also alternative sequences that can be performed in a single breath-hold or with free breathing. Radiologists need to be aware of factors affecting image quality, and potential pitfalls and artefacts that may generate focal hyperintense areas that mimic myocardial scar.

Diffuse myocardial fibrosis evaluation using cardiac magnetic resonance T1 mapping: sample size considerations for clinical trials

BACKGROUND

Cardiac magnetic resonance (CMR) T1 mapping has been used to characterize myocardial diffuse fibrosis. The aim of this study is to determine the reproducibility and sample size of CMR fibrosis measurements that would be applicable in clinical trials.

METHODS

A modified Look-Locker with inversion recovery (MOLLI) sequence was used to determine myocardial T1 values pre-, and 12 and 25min post-administration of a gadolinium-based contrast agent at 3 Tesla. For 24 healthy subjects (8 men; 29 ± 6 years), two separate scans were obtained a) with a bolus of 0.15mmol/kg of gadopentate dimeglumine and b) 0.1mmol/kg of gadobenate dimeglumine, respectively, with averaged of 51 ± 34 days between two scans. Separately, 25 heart failure subjects (12 men; 63 ± 14 years), were evaluated after a bolus of 0.15mmol/kg of gadopentate dimeglumine. Myocardial partition coefficient (λ) was calculated according to (ΔR1myocardium/ΔR1blood), and ECV was derived from λ by adjusting (1-hematocrit).

RESULTS

Mean ECV and λ were both significantly higher in HF subjects than healthy (ECV: 0.287 ± 0.034 vs. 0.267 ± 0.028, p=0.002; λ: 0.481 ± 0.052 vs. 442 ± 0.037, p < 0.001, respectively). The inter-study ECV and λ variation were about 2.8 times greater than the intra-study ECV and λ variation in healthy subjects (ECV:0.017 vs. 0.006, λ:0.025 vs. 0.009, respectively). The estimated sample size to detect ECV change of 0.038 or λ change of 0.063 (corresponding to ~3% increase of histological myocardial fibrosis) with a power of 80% and an alpha error of 0.05 for heart failure subjects using a two group design was 27 in each group, respectively.

CONCLUSION

ECV and λ quantification have a low variability across scans, and could be a viable tool for evaluating clinical trial outcome.

T1 Mapping in cardiomyopathy at cardiac MR: comparison with endomyocardial biopsy

PURPOSE

To determine the utility of cardiac magnetic resonance (MR) T1 mapping for quantification of diffuse myocardial fibrosis compared with the standard of endomyocardial biopsy.

MATERIALS AND METHODS

This HIPAA-compliant study was approved by the institutional review board. Cardiomyopathy patients were retrospectively identified who had undergone endomyocardial biopsy and cardiac MR at one institution during a 5-year period. Forty-seven patients (53% male; mean age, 46.8 years) had undergone diagnostic cardiac MR and endomyocardial biopsy. Thirteen healthy volunteers (54% male; mean age, 38.1 years) underwent cardiac MR as a reference. Myocardial T1 mapping was performed 10.7 minutes ± 2.7 (standard deviation) after bolus injection of 0.2 mmol/kg gadolinium chelate by using an inversion-recovery Look-Locker sequence on a 1.5-T MR imager. Late gadolinium enhancement was assessed by using gradient-echo inversion-recovery sequences. Cardiac MR results were the consensus of two radiologists who were blinded to histopathologic findings. Endomyocardial biopsy fibrosis was quantitatively measured by using automated image analysis software with digital images of specimens stained with Masson trichrome. Histopathologic findings were reported by two pathologists blinded to cardiac MR findings. Statistical analyses included Mann-Whitney U test, analysis of variance, and linear regression.

RESULTS

Median myocardial fibrosis was 8.5% (interquartile range, 5.7-14.4). T1 times were greater in control subjects than in patients without and in patients with evident late gadolinium enhancement (466 msec ± 14, 406 msec ± 59, and 303 msec ± 53, respectively; P < .001). T1 time and histologic fibrosis were inversely correlated (r = -0.57; 95% confidence interval: -0.74, -0.34; P < .0001). The area under the curve for myocardial T1 time to detect fibrosis of greater than 5% was 0.84 at a cutoff of 383 msec.

CONCLUSION

Cardiac MR with T1 mapping can provide noninvasive evidence of diffuse myocardial fibrosis in patients referred for evaluation of cardiomyopathy.

Comparison of novel risk markers for improvement in cardiovascular risk assessment in intermediate-risk individuals

CONTEXT

Risk markers including coronary artery calcium, carotid intima-media thickness, ankle-brachial index, brachial flow-mediated dilation, high-sensitivity C-reactive protein (CRP), and family history of coronary heart disease (CHD) have been reported to improve on the Framingham Risk Score (FRS) for prediction of CHD, but there are no direct comparisons of these markers for risk prediction in a single cohort.

OBJECTIVE

We compared improvement in prediction of incident CHD/cardiovascular disease (CVD) of these 6 risk markers within intermediate-risk participants (FRS >5%-<20%) in the Multi-Ethnic Study of Atherosclerosis (MESA).

DESIGN, SETTING, AND PARTICIPANTS

Of 6814 MESA participants from 6 US field centers, 1330 were intermediate risk, without diabetes mellitus, and had complete data on all 6 markers. Recruitment spanned July 2000 to September 2002, with follow-up through May 2011. Probability-weighted Cox proportional hazard models were used to estimate hazard ratios (HRs). Area under the receiver operator characteristic curve (AUC) and net reclassification improvement were used to compare incremental contributions of each marker when added to the FRS, plus race/ethnicity.

MAIN OUTCOME MEASURES

Incident CHD defined as myocardial infarction, angina followed by revascularization, resuscitated cardiac arrest, or CHD death. Incident CVD additionally included stroke or CVD death.

RESULTS

After 7.6-year median follow-up (IQR, 7.3-7.8), 94 CHD and 123 CVD events occurred. Coronary artery calcium, ankle-brachial index, high-sensitivity CRP, and family history were independently associated with incident CHD in multivariable analyses (HR, 2.60 [95% CI, 1.94-3.50]; HR, 0.79 [95% CI, 0.66-0.95]; HR, 1.28 [95% CI, 1.00-1.64]; and HR, 2.18 [95% CI, 1.38-3.42], respectively). Carotid intima-media thickness and brachial flow-mediated dilation were not associated with incident CHD in multivariable analyses (HR, 1.17 [95% CI, 0.95-1.45] and HR, 0.95 [95% CI, 0.78-1.14]). Although addition of the markers individually to the FRS plus race/ethnicity improved AUC, coronary artery calcium afforded the highest increment (0.623 vs 0.784), while brachial flow-mediated dilation had the least (0.623 vs 0.639). For incident CHD, the net reclassification improvement with coronary artery calcium was 0.659, brachial flow-mediated dilation was 0.024, ankle-brachial index was 0.036, carotid intima-media thickness was 0.102, family history was 0.160 and high-sensitivity CRP was 0.079. Similar results were obtained for incident CVD.

CONCLUSIONS

Coronary artery calcium, ankle-brachial index, high-sensitivity CRP, and family history were independent predictors of incident CHD/CVD in intermediate-risk individuals. Coronary artery calcium provided superior discrimination and risk reclassification compared with other risk markers.

CKD, plasma lipids, and common carotid intima-media thickness: results from the multi-ethnic study of atherosclerosis

BACKGROUND AND OBJECTIVES

Altered levels of atherogenic lipoproteins have been shown to be common in mild kidney dysfunction. This study sought to determine the associations between plasma lipids (including LDL particle distribution) and subclinical atherosclerosis measured by the common carotid intima-media thickness (IMT) across levels of estimated GFR (eGFR) and to assess whether inflammation modifies these associations.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Cross-sectional analyses of 6572 participants in the Multi-Ethnic Study of Atherosclerosis enrolled from 2000 to 2002 were performed.

RESULTS

CKD, defined as eGFR <60 ml/min per 1.73 m(2), was present in 853 individuals (13.0%). Associations of total cholesterol and LDL cholesterol (LDL-C) with IMT were J shaped, particularly among participants with CKD (P value for interaction, P=0.01). HDL cholesterol (HDL-C) and small-dense LDL-C were consistently and linearly associated with IMT across levels of eGFR. The results showed differences in IMT of -21.41 (95% confidence interval, -41.00, -1.57) in eGFR ≥60 and -58.49 (-126.61, 9.63) in eGFR <60 per unit difference in log-transformed HDL-C, and 4.83 (3.16, 6.50) in eGFR ≥60 and 7.48 (1.45, 13.50) in eGFR <60 per 100 nmol/L difference in small-dense LDL. Among participants with CKD, inflammation significantly modified the associations of total cholesterol and LDL-C with IMT (P values for interaction, P<0.01 and P<0.001, respectively).

CONCLUSIONS

Compared with total cholesterol and LDL-C, abnormalities in HDL-C and small-dense LDL-C are more strongly and consistently associated with subclinical atherosclerosis in CKD. Inflammation modifies the association between total cholesterol and LDL-C with IMT.

Dietary intake of saturated fat by food source and incident cardiovascular disease: the Multi-Ethnic Study of Atherosclerosis

BACKGROUND

Although dietary recommendations have focused on restricting saturated fat (SF) consumption to reduce cardiovascular disease (CVD) risk, evidence from prospective studies has not supported a strong link between total SF intake and CVD events. An understanding of whether food sources of SF influence these relations may provide new insights.

OBJECTIVE

We investigated the association of SF consumption from different food sources and the incidence of CVD events in a multiethnic population.

DESIGN

Participants who were 45-84 y old at baseline (n = 5209) were followed from 2000 to 2010. Diet was assessed by using a 120-item food-frequency questionnaire. CVD incidence (316 cases) was assessed during follow-up visits.

RESULTS

After adjustment for demographics, lifestyle, and dietary confounders, a higher intake of dairy SF was associated with lower CVD risk [HR (95% CI) for +5 g/d and +5% of energy from dairy SF: 0.79 (0.68, 0.92) and 0.62 (0.47, 0.82), respectively]. In contrast, a higher intake of meat SF was associated with greater CVD risk [HR (95% CI) for +5 g/d and a +5% of energy from meat SF: 1.26 (1.02, 1.54) and 1.48 (0.98, 2.23), respectively]. The substitution of 2% of energy from meat SF with energy from dairy SF was associated with a 25% lower CVD risk [HR (95% CI): 0.75 (0.63, 0.91)]. No associations were observed between plant or butter SF and CVD risk, but ranges of intakes were narrow.

CONCLUSION

Associations of SF with health may depend on food-specific fatty acids or other nutrient constituents in foods that contain SF, in addition to SF.

High-density lipoprotein cholesterol and particle concentrations, carotid atherosclerosis, and coronary events: MESA (multi-ethnic study of atherosclerosis)

OBJECTIVES

The purpose of this study was to evaluate independent associations of high-density lipoprotein cholesterol (HDL-C) and particle (HDL-P) concentrations with carotid intima-media thickness (cIMT) and incident coronary heart disease (CHD).

BACKGROUND

HDL-C is inversely related to CHD, and also to triglycerides, low-density lipoprotein particles (LDL-P), and related metabolic risk. HDL-P associations with CHD may be partially independent of these factors.

METHODS

In a multiethnic study of 5,598 men and women ages 45 to 84 years old, without baseline CHD, excluding subjects on lipid-lowering medications, triglycerides >400 mg/dl, or missing values, we evaluated associations of HDL-C and nuclear magnetic resonance spectroscopy-measured HDL-P with cIMT and incident CHD (myocardial infarction, CHD death, and angina, n = 227 events; mean 6.0 years follow-up). All models were adjusted for age, sex, ethnicity, hypertension, and smoking.

RESULTS

HDL-C and HDL-P correlated with each other (ρ = 0.69) and LDL-P (ρ = -0.38, -0.25, respectively, p < 0.05 for all). For (1 SD) higher HDL-C (15 mg/dl) or HDL-P (6.64 μmol/l), cIMT differences were - 26.1 (95% confidence interval [CI]: -34.7 to -17.4) μm and -30.1 (95% CI: -38.8 to - 21.4) μm, and CHD hazard ratios were 0.74 (95% CI: 0.63 to 0.88) and 0.70 (95% CI: 0.59 to 0.82), respectively. Adjusted for each other and LDL-P, HDL-C was no longer associated with cIMT (2.3; 95% CI: - 9.5 to 14.2 μm) or CHD (0.97; 95% CI: 0.77 to 1.22), but HDL-P remained independently associated with cIMT (-22.2; 95% CI: - 33.8 to -10.6 μm) and CHD (0.75; 95% CI: 0.61 to 0.93). Interactions by sex, ethnicity, diabetes, and high-sensitivity C-reactive protein were not significant.

CONCLUSIONS

Adjusting for each other and LDL-P substantially attenuated associations of HDL-C, but not HDL-P, with cIMT and CHD. Potential confounding by related lipids or lipoproteins should be carefully considered when evaluating HDL-related risk.

Interstitial myocardial fibrosis assessed as extracellular volume fraction with low-radiation-dose cardiac CT

PURPOSE

To develop a cardiac computed tomographic (CT) method with which to determine extracellular volume (ECV) fraction, with cardiac magnetic resonance (MR) imaging as the reference standard.

MATERIALS AND METHODS

Study participants provided written informed consent to participate in this institutional review board-approved study. ECV was measured in healthy subjects and patients with heart failure by using cardiac CT and cardiac MR imaging. Paired Student t test, linear regression analysis, and Pearson correlation analysis were used to determine the relationship between cardiac CT and MR imaging ECV values and clinical parameters.

RESULTS

Twenty-four subjects were studied. There was good correlation between myocardial ECV measured at cardiac MR imaging and that measured at cardiac CT (r = 0.82, P < .001). As expected, ECV was higher in patients with heart failure than in healthy control subjects for both cardiac CT and cardiac MR imaging (P = .03, respectively). For both cardiac MR imaging and cardiac CT, ECV was positively associated with end diastolic and end systolic volume and inversely related to ejection fraction (P < .05 for all). Mean radiation dose was 1.98 mSv ± 0.16 (standard deviation) for each cardiac CT acquisition.

CONCLUSION

ECV at cardiac CT and that at cardiac MR imaging showed good correlation, suggesting the potential for myocardial tissue characterization with cardiac CT.

T1 mapping of the myocardium: intra-individual assessment of the effect of field strength, cardiac cycle and variation by myocardial region

BACKGROUND

Myocardial T1 relaxation time (T1 time) and extracellular volume fraction (ECV) are altered in the presence of myocardial fibrosis. The purpose of this study was to evaluate acquisition factors that may result in variation of measured T1 time and ECV including magnetic field strength, cardiac phase and myocardial region.

METHODS

31 study subjects were enrolled and underwent one cardiovascular MR exam at 1.5 T and two exams at 3 T, each on separate days. A Modified Look-Locker Inversion Recovery (MOLLI) sequence was acquired before and 5, 10, 12, 20, 25 and 30 min after administration of 0.15 mmol/kg gadopentetate dimeglumine (Gd-DTPA; Magnevist) at 1.5 T (exam 1). For exam 2, MOLLI sequences were acquired at 3 T both during diastole and systole, before and after administration of Gd-DTPA (0.15 mmol/kg Magnevist).Exam 3 was identical to exam 2 except gadobenate dimeglumine was administered (Gd-BOPTA; 0.1 mmol/kg Multihance). T1 times were measured in myocardium and blood. ECV was calculated by (ΔR1myocardium/ΔR1blood)*(1-hematocrit).

RESULTS

Before gadolinium, T1 times of myocardium and blood were significantly greater at 3 T versus 1.5 T (28% and 31% greater, respectively, p < 0.001); after gadolinium, 3 T values remained greater than those at 1.5 T (14% and 12% greater for myocardium and blood at 3 T with Gd-DTPA, respectively, p < 0.0001 and 18% and 15% greater at 3 T with Gd-BOPTA, respectively, p < 0.0001). However, ECV did not vary significantly with field strength when using the same contrast agent at equimolar dose (p = 0.2). Myocardial T1 time was 1% shorter at systole compared to diastole pre-contrast and 2% shorter at diastole compared to systole post-contrast (p < 0.01). ECV values were greater during diastole compared to systole on average by 0.01 (p < 0.01 to p < 0.0001). ECV was significantly higher for the septum compared to the non-septal myocardium for all three exams (p < 0.0001-0.01) with mean absolute differences of 0.01, 0.004, and 0.07, respectively, for exams 1, 2 and 3.

CONCLUSION

ECV is similar at field strengths of 1.5 T and 3 T. Due to minor variations in T1 time and ECV during the cardiac cycle and in different myocardial regions, T1 measurements should be obtained at the same cardiac phase and myocardial region in order to obtain consistent results.

T1 mapping of the myocardium: intra-individual assessment of post-contrast T1 time evolution and extracellular volume fraction at 3T for Gd-DTPA and Gd-BOPTA

PURPOSE

Myocardial T1 relaxation time (T1 time) and extracellular volume fraction (ECV) are altered in patients with diffuse myocardial fibrosis. The purpose of this study was to perform an intra-individual assessment of normal T1 time and ECV for two different contrast agents.

METHODS

A modified Look-Locker Inversion Recovery (MOLLI) sequence was acquired at 3 T in 24 healthy subjects (8 men; 28 ± 6 years) at mid-ventricular short axis pre-contrast and every 5 min between 5-45 min after injection of a bolus of 0.15 mmol/kg gadopentetate dimeglumine (Gd-DTPA; Magnevist®) (exam 1) and 0.1 mmol/kg gadobenate dimeglumine (Gd-BOPTA; Multihance®) (exam 2) during two separate scanning sessions. T1 times were measured in myocardium and blood on generated T1 maps. ECVs were calculated as ΔR1 myocardium/ΔR1 blood*1-hematocrit.

RESULTS

Mean pre-contrast T1 relaxation times for myocardium and blood were similar for both the first and second CMR exam (p > 0.5). Overall mean post-contrast myocardial T1 time was 15 ± 2 ms (2.5 ± 0.7%) shorter for Gd-DTPA at 0.15 mmol/kg compared to Gd-BOPTA at 0.1 mmol/kg (p < 0.01) while there was no significant difference for T1 time of blood pool (p > 0.05). Between 5 and 45 minutes after contrast injection, mean ECV values increased linearly with time for both contrast agents from 0.27 ± 0.03 to 0.30 ± 0.03 (p < 0.0001). Mean ECV values were slightly higher (by 0.01, p < 0.05) for Gd-DTPA compared to Gd-BOPTA. Inter-individual variation of ECV was higher (CV 8.7% [exam 1, Gd-DTPA] and 9.4% [exam 2, Gd-BOPTA], respectively) compared to variation of pre-contrast myocardial T1 relaxation time (CV 4.5% [exam 1] and 3.0% [exam 2], respectively). ECV with Gd-DTPA was highly correlated to ECV by Gd-BOPTA (r = 0.803; p < 0.0001).

CONCLUSION

In comparison to pre-contrast myocardial T1 relaxation time, variation in ECV values of normal subjects is larger. However, absolute differences in ECV between Gd-DTPA and Gd-BOPTA were small and rank correlation was high. There is a small and linear increase in ECV over time, therefore ideally images should be acquired at the same delay after contrast injection.

Extracellular volume imaging by magnetic resonance imaging provides insights into overt and sub-clinical myocardial pathology

AIMS

Conventional late gadolinium enhancement (LGE) cardiac magnetic resonance can detect myocardial infarction and some forms of non-ischaemic myocardial fibrosis. However, quantitative imaging of extracellular volume fraction (ECV) may be able to detect subtle abnormalities such as diffuse fibrosis or post-infarct remodelling of remote myocardium. The aims were (1) to measure ECV in myocardial infarction and non-ischaemic myocardial fibrosis, (2) to determine whether ECV varies with age, and (3) to detect sub-clinical abnormalities in 'normal appearing' myocardium remote from regions of infarction.

METHODS AND RESULTS

Cardiac magnetic resonance ECV imaging was performed in 126 patients with T1 mapping before and after injection of gadolinium contrast. Conventional LGE images were acquired for the left ventricle. In patients with a prior myocardial infarction, the infarct region had an ECV of 51 ± 8% which did not overlap with the remote 'normal appearing' myocardium that had an ECV of 27 ± 3% (P < 0.001, n = 36). In patients with non-ischaemic cardiomyopathy, the ECV of atypical LGE was 37 ± 6%, whereas the 'normal appearing' myocardium had an ECV of 26 ± 3% (P < 0.001, n = 30). The ECV of 'normal appearing' myocardium increased with age (r = 0.28, P = 0.01, n = 60). The ECV of 'normal appearing' myocardium remote from myocardial infarctions increased as left ventricular ejection fraction decreased (r = -0.50, P = 0.02).

CONCLUSION

Extracellular volume fraction imaging can quantitatively characterize myocardial infarction, atypical diffuse fibrosis, and subtle myocardial abnormalities not clinically apparent on LGE images. Taken within the context of prior literature, these subtle ECV abnormalities are consistent with diffuse fibrosis related to age and changes remote from infarction.

Myocardial T1 and extracellular volume fraction mapping at 3 tesla

BACKGROUND

To compare 11 heartbeat (HB) and 17 HB modified lock locker inversion recovery (MOLLI) pulse sequence at 3T and to establish preliminary reference values for myocardial T1 and the extracellular volume fraction (ECV).

METHODS

Both phantoms and normal volunteers were scanned at 3T using 11 HB and 17 HB MOLLI sequence with the following parameters: spatial resolution = 1.75 × 1.75 × 10 mm on a 256 × 180 matrix, TI initial = 110 ms, TI increment = 80 ms, flip angle = 35°, TR/TE = 1.9/1.0 ms. All volunteers were administered Gadolinium-DTPA (Magnevist, 0.15 mmol/kg), and multiple post-contrast MOLLI scans were performed at the same pre-contrast position from 3.5-23.5 minutes after a bolus contrast injection. Late gadolinium enhancement (LGE) images were also acquired 12-30 minutes after the gadolinium bolus.

RESULTS

T1 values of 11 HB and 17 HB MOLLI displayed good agreement in both phantom and volunteers. The average pre-contrast myocardial and blood T1 was 1315 ± 39 ms and 2020 ± 129 ms, respectively. ECV was stable between 8.5 to 23.5 minutes post contrast with an average of 26.7 ± 1.0%.

CONCLUSION

The 11 HB MOLLI is a faster method for high-resolution myocardial T1 mapping at 3T. ECV fractions are stable over a wide time range after contrast administration.

Electrocardiographic abnormalities associated with the metabolic syndrome and its components: the multi-ethnic study of atherosclerosis

BACKGROUND

The association between metabolic syndrome and electrocardiographic (ECG) abnormalities is not well established.

METHODS

ECG tracings of 6,765 men and women aged 45-84 years, free of clinical cardiovascular disease, from the Multi-Ethnic Study of Atherosclerosis were obtained (2000-2002) and classified as normal or having major or minor abnormalities. We evaluated the associations of metabolic syndrome and its components with ECG abnormalities, adjusting for age, ethnicity, and gender and testing for effect modification by ethnicity and gender.

RESULTS

The associations of metabolic syndrome, hypertension, and high triglycerides with ECG abnormalities varied significantly by gender. In males, metabolic syndrome and hypertension were significantly associated with major ECG abnormality [1.69 (1.33-2.13), and 2.22 (1.72-2.86), respectively] after adjusting for ethnicity and gender. Hypertension was also associated significantly with minor ECG abnormality in males after adjusting for age and ethnicity. In females, metabolic syndrome and hypertension were significantly associated with major [1.84 (1.44-2.37), and 1.68 (1.27-2.22), respectively] and minor [1.38 (1.19-1.59), and 1.53 (1.32-1.79), respectively] ECG abnormalities after adjusting for age and ethnicity. High triglycerides were only significantly associated with major ECG abnormality in females after adjusting for age and ethnicity. After adjusting for age, ethnicity, and gender, central obesity and high fasting blood glucose were significantly associated with major and minor ECG abnormalities, whereas low high-density lipoprotein cholesterol was significantly associated with major ECG abnormality only.

CONCLUSIONS

Metabolic syndrome and its components are associated with major and/or minor ECG abnormalities. The relationship of metabolic syndrome, hypertension, and high triglycerides with ECG abnormalities varied according to gender.