National lipid association recommendations for patient-centered management of dyslipidemia: part 1--full report

The leadership of the National Lipid Association convened an Expert Panel to develop a consensus set of recommendations for patient-centered management of dyslipidemia in clinical medicine. An Executive Summary of those recommendations was previously published. This document provides support for the recommendations outlined in the Executive Summary. The major conclusions include (1) an elevated level of cholesterol carried by circulating apolipoprotein B-containing lipoproteins (non-high-density lipoprotein cholesterol and low-density lipoprotein cholesterol [LDL-C], termed atherogenic cholesterol) is a root cause of atherosclerosis, the key underlying process contributing to most clinical atherosclerotic cardiovascular disease (ASCVD) events; (2) reducing elevated levels of atherogenic cholesterol will lower ASCVD risk in proportion to the extent that atherogenic cholesterol is reduced. This benefit is presumed to result from atherogenic cholesterol lowering through multiple modalities, including lifestyle and drug therapies; (3) the intensity of risk-reduction therapy should generally be adjusted to the patient's absolute risk for an ASCVD event; (4) atherosclerosis is a process that often begins early in life and progresses for decades before resulting a clinical ASCVD event. Therefore, both intermediate-term and long-term or lifetime risk should be considered when assessing the potential benefits and hazards of risk-reduction therapies; (5) for patients in whom lipid-lowering drug therapy is indicated, statin treatment is the primary modality for reducing ASCVD risk; (6) nonlipid ASCVD risk factors should also be managed appropriately, particularly high blood pressure, cigarette smoking, and diabetes mellitus; and (7) the measurement and monitoring of atherogenic cholesterol levels remain an important part of a comprehensive ASCVD prevention strategy.

National Lipid Association recommendations for patient-centered management of dyslipidemia: part 1 - executive summary

Various organizations and agencies have issued recommendations for the management of dyslipidemia. Although many commonalities exist among them, material differences are present as well. The leadership of the National Lipid Association (NLA) convened an Expert Panel to develop a consensus set of recommendations for patient-centered management of dyslipidemia in clinical medicine. The current Executive Summary highlights the major conclusions in Part 1 of the recommendations report of the NLA Expert Panel and includes: (1) background and conceptual framework for formulation of the NLA Expert Panel recommendations; (2) screening and classification of lipoprotein lipid levels in adults; (3) targets for intervention in dyslipidemia management; (4) atherosclerotic cardiovascular disease risk assessment and treatment goals based on risk category; (5) atherogenic cholesterol-non-high-density lipoprotein cholesterol and low-density lipoprotein cholesterol-as the primary targets of therapy; and (6) lifestyle and drug therapies intended to reduce morbidity and mortality associated with dyslipidemia.

Human embryonic-stem-cell-derived cardiomyocytes regenerate non-human primate hearts

Pluripotent stem cells provide a potential solution to current epidemic rates of heart failure by providing human cardiomyocytes to support heart regeneration. Studies of human embryonic-stem-cell-derived cardiomyocytes (hESC-CMs) in small-animal models have shown favourable effects of this treatment. However, it remains unknown whether clinical-scale hESC-CM transplantation is feasible, safe or can provide sufficient myocardial regeneration. Here we show that hESC-CMs can be produced at a clinical scale (more than one billion cells per batch) and cryopreserved with good viability. Using a non-human primate model of myocardial ischaemia followed by reperfusion, we show that cryopreservation and intra-myocardial delivery of one billion hESC-CMs generates extensive remuscularization of the infarcted heart. The hESC-CMs showed progressive but incomplete maturation over a 3-month period. Grafts were perfused by host vasculature, and electromechanical junctions between graft and host myocytes were present within 2 weeks of engraftment. Importantly, grafts showed regular calcium transients that were synchronized to the host electrocardiogram, indicating electromechanical coupling. In contrast to small-animal models, non-fatal ventricular arrhythmias were observed in hESC-CM-engrafted primates. Thus, hESC-CMs can remuscularize substantial amounts of the infarcted monkey heart. Comparable remuscularization of a human heart should be possible, but potential arrhythmic complications need to be overcome.

Real time three-dimensional echocardiography evaluation of intracardiac masses

The evaluation of cardiac masses is often a challenge for cardiac imaging techniques. The traditional standby has been two-dimensional echocardiography (2DE). Real time three-dimensional echocardiography (RT3DE) offers incremental value for the evaluation of intracardiac masses by providing more accurate assessment of the size and shape of the mass as well as in some cases, composition of the mass. RT3DE aids with the relationship between the mass and adjacent structures. Therefore, here we discuss the subject of RT3DE evaluation of cardiac masses is reviewed and discussed in detail.

Increased mortality in patients with conflicting diastolic parameters

The aim of this study was to describe the clinical characteristics and mortality of patients with conflicting diastolic function during follow-up. Up to 30% of patients have conflicting diastolic function by echo Doppler and therefore cannot be classified into a distinct diastolic dysfunction category of stage 1, 2 or 3. Using our established echocardiography data base, we studied a cohort of 250 subjects with conflicting diastolic function. Each individual was compared to two controls with normal diastolic and systolic function. The pre-specified goal of the analysis was a 6-year follow-up. Patients with conflicting diastolic function were more likely to have diabetes, hypertension, and established coronary artery disease. The Cox proportional hazards model determined that the risk of death was significantly higher for conflicting patients compared to patients with normal diastolic parameters (HR: 1.83; 95% CI: 1.32-2.53), P < 0.001. After adjustment for covariates, the risk of death remained elevated for the conflicting group (HR: 1.56; 95% CI: 1.11-2.18), P = 0.009. Conflicting diastolic dysfunction is associated with an increased risk of death compared to individuals with normal function. In conclusion, this emphasizes the need to attain a more precise characterization and categorization for patients with diastolic dysfunction.

Common genetic variation, residential proximity to traffic exposure, and left ventricular mass: the multi-ethnic study of atherosclerosis

BACKGROUND

Elevated left ventricular mass (LVM) is a strong predictor of negative cardiovascular outcomes, including heart failure, stroke, and sudden cardiac death. A relationship between close (< 50 m compared with > 150 m) residential proximity to major roadways and higher LVM has previously been described, but the mechanistic pathways that are involved in this relationship are not known. Understanding genetic factors that influence susceptibility to these effects may provide insight into relevant mechanistic pathways.

OBJECTIVE

We set out to determine whether genetic polymorphisms in genes affecting vascular and autonomic function, blood pressure, or inflammation influence the relationship between traffic proximity and LVM.

METHODS

This was a cross-sectional study of 1,376 genotyped participants in the Multi-Ethnic Study of Atherosclerosis, with cardiac magnetic resonance imaging performed between 2000 and 2002. The impact of tagged single-nucleotide polymorphisms (tagSNPs) and inferred haplotypes in 12 candidate genes (ACE, ADRB2, AGT, AGTR1, ALOX15, EDN1, GRK4, PTGS1, PTGS2, TLR4, VEGFA, and VEGFB) on the relationship between residential proximity to major roadways and LVM was analyzed using multiple linear regression, adjusting for multiple potential confounders.

RESULTS

After accounting for multiple testing and comparing homozygotes, tagSNPs in the type 1 angiotensin II receptor (AGTR1, rs6801836) and arachidonate 15-lipoxygenase (ALOX15, rs2664593) genes were each significantly (q < 0.2) associated with a 9-10% difference in the association between residential proximity to major roadways and LVM. Participants with suboptimal blood pressure control demonstrated stronger interactions between AGTR1 and traffic proximity.

CONCLUSIONS

Common polymorphisms in genes responsible for vascular function, inflammation, and oxidative stress appear to modify associations between proximity to major roadways and LVM. Further understanding of how genes modify effects of air pollution on CVD may help guide research efforts into specific mechanistic pathways.

Carotid intima-media thickness for the practicing lipidologist

BACKGROUND

It is well known that cardiovascular disease is the number one killer of men and women in the United States and in many parts of the developed world. However, early detection of atherosclerosis remains a challenging area of research and development. Stress echo and myocardial perfusion studies were not designed to be screening tests and the majority of literature using these tests is in populations with a high probability of disease. It must be emphasized that negative stress echo and stress MPI tests only imply a lack of flow limiting disease; they do not indicate lack of atherosclerotic disease. It is important to remember that when these tests are "negative," the implication is favorable short-term prognosis rather than any implication regarding lack of disease. In contrast, carotid intima-media thickness (CIMT) scanning protocols can detect atherosclerotic disease in early and asymptomatic stages. For a number of reasons reviewed in this article, CIMT may be a more optimal screening and risk-stratifying technology: CIMT directly visualizes vasculature unlike biomarkers such as LDL cholesterol, hsCRP, or PLA2.

METHODS

We performed medline searches for original articles and reviews of carotid IMT from 1985 to the present. We particularly emphasized large multi-center epidemiologic studies of the natural history of patients with carotid IMT measurements.

CONCLUSION

There is substantial evidence that CIMT is a suitable surrogate for the coronary tree. CIMT is also (along with coronary calcium scoring) recognized by the American Heart Association as a surrogate marker for coronary artery disease. A recent commentary by Stein, et al reviewed the comparison of CIMT to coronary calcium scoring, with favorable findings for CIMT especially in the healthy young and middle-aged populations, as well as women and African American individuals where coronary calcification has more limited utility. Recent findings of the Multi-Ethnic Study of Atherosclerosis indicate further that increased CIMT predicted CVD events in individuals without coronary calcification.

Exposure to traffic and left ventricular mass and function: the Multi-Ethnic Study of Atherosclerosis

RATIONALE

Ambient air pollution has been associated with heart failure morbidity and mortality. The mechanisms responsible for these associations are unknown but may include the effects of traffic-related pollutants on vascular or autonomic function.

OBJECTIVES

We assessed the cross-sectional relation between long-term air pollution, traffic exposures, and important end-organ measures of alterations in cardiac function-left ventricular mass index (LVMI) and ejection fraction-in the Multi-Ethnic Study of Atherosclerosis, a multicenter study of adults without previous clinical cardiovascular disease.

METHODS

A total of 3,827 eligible participants (aged 45-84 yr) underwent cardiac magnetic resonance imaging between 2000 and 2002. We estimated air pollution exposures using residential proximity to major roadways and interpolated concentrations of fine particulate matter (less than 2.5 microns in diameter). We examined adjusted associations between these exposures and left ventricular mass and function.

MEASUREMENTS AND MAIN RESULTS

Relative to participants living more than 150 m from a major roadway, participants living within 50 m of a major roadway showed an adjusted 1.4 g/m(2) (95% CI, 0.3-2.5) higher LVMI, a difference in mass corresponding to a 5.6 mm Hg greater systolic blood pressure. Ejection fraction was not associated with proximity to major roadways. Limited variability in estimates of fine particulate matter was observed within cities, and no associations with particulate matter were found for either outcome after adjustment for center.

CONCLUSIONS

Living in close proximity to major roadways is associated with higher LVMI, suggesting chronic vascular end-organ damage from a traffic-related environmental exposure. Air pollutants or another component of roadway proximity, such as noise, could be responsible.

Diesel exhaust inhalation elicits acute vasoconstriction in vivo

BACKGROUND

Traffic-related air pollution is consistently associated with cardiovascular morbidity and mortality. Recent human and animal studies suggest that exposure to air pollutants affects vascular function. Diesel exhaust (DE) is a major source of traffic-related air pollution.

OBJECTIVES

Our goal was to study the effects of short-term exposure to DE on vascular reactivity and on mediators of vascular tone.

METHODS

In a double-blind, crossover, controlled exposure study, 27 adult volunteers (10 healthy and 17 with metabolic syndrome) were exposed in randomized order to filtered air (FA) and each of two levels of diluted DE (100 or 200 microg/m(3) of fine particulate matter) in 2-hr sessions. Before and after each exposure, we assessed the brachial artery diameter (BAd) by B-mode ultrasound and collected blood samples for endothelin-1 (ET-1) and catecholamines. Postexposure we also assessed endothelium-dependent flow-mediated dilation (FMD).

RESULTS

Compared with FA, DE at 200 microg/m(3) elicited a decrease in BAd (0.11 mm; 95% confidence interval, 0.02-0.18), and the effect appeared linearly dose related with a smaller effect at 100 microg/m(3). Plasma levels of ET-1 increased after 200 microg/m(3) DE but not after FA (p = 0.01). There was no consistent impact of DE on plasma catecholamines or FMD.

CONCLUSIONS

These results demonstrate that short-term exposure to DE is associated with acute endothelial response and vasoconstriction of a conductance artery. Elucidation of the signaling pathways controlling vascular tone that underlie this observation requires further study.

Cardiomyocytes derived from human embryonic stem cells in pro-survival factors enhance function of infarcted rat hearts

Cardiomyocytes derived from human embryonic stem (hES) cells potentially offer large numbers of cells to facilitate repair of the infarcted heart. However, this approach has been limited by inefficient differentiation of hES cells into cardiomyocytes, insufficient purity of cardiomyocyte preparations and poor survival of hES cell-derived myocytes after transplantation. Seeking to overcome these challenges, we generated highly purified human cardiomyocytes using a readily scalable system for directed differentiation that relies on activin A and BMP4. We then identified a cocktail of pro-survival factors that limits cardiomyocyte death after transplantation. These techniques enabled consistent formation of myocardial grafts in the infarcted rat heart. The engrafted human myocardium attenuated ventricular dilation and preserved regional and global contractile function after myocardial infarction compared with controls receiving noncardiac hES cell derivatives or vehicle. The ability of hES cell-derived cardiomyocytes to partially remuscularize myocardial infarcts and attenuate heart failure encourages their study under conditions that closely match human disease.

Intraventricular Dyssynchrony Assessment by Real-Time Three-Dimensional Echocardiography

Heart failure is exceedingly prevalent in the United States and in other developed countries. Treatment regimens are complex and now include electrical therapy. Methods for evaluating left ventricular dyssynchrony using echocardiography rather than QRS duration have been developed, with tissue Doppler velocity parameters being the most popular. Real-time three-dimensional echocardiography is another novel method for dyssynchrony evaluation that has potential advantages over existing techniques. The authors describe their experience with three-dimensional echocardiography dyssynchrony evaluation and offer insights into the direction that this technology must move to improve results.

Three-Dimensional Echocardiography: An Alternative Imaging Choice for Evaluation of Tricuspid Valve Disorders

This article presents an approach to real-time three-dimensional imaging of the tricuspid valve from three different views. This is followed by some representative cases that illustrate these views and some unique tricuspid valve abnormalities, including one case of corrected transposition.

Three-Dimensional Echocardiography: An Historical Perspective

Three-dimensional echocardiography (3DE) has made a dramatic transition from predominantly a research tool to a technology useful in everyday clinical practice. This article outlines the history of 3DE from its beginnings to the most current technology.

Interventional Three-Dimensional Echocardiography: Using Real-time Three-Dimensional Echocardiography to Guide and Evaluate Intracardiac Therapies

Real-time three-dimensional echocardiography (RT3DE) already has demonstrated its utility in guiding intracardiac procedures. This article discusses the advantages RT3DE has over the previous standard of 2D echocardiography.

The Use of Three-Dimensional Echocardiography for the Evaluation of and Treatment of Mitral Stenosis

To date, mitral stenosis has been evaluated by both hemodynamic data derived from catheterization as well as 2D and Doppler echocardiography. However, the advent of real-time 3D echocardiography has allowed more precise measurement of the mitral valve orifice by planimetry. In addition, evaluation of the mitral commissures prior to and after percutaneous mitral valvuloplasty is greatly aided by 3D echocardiography. Here we discuss these subjects as well as provide specific clinical trials that support the use of real-time 3D echocardiography for the evaluation and treatment of mitral stenosis.