Is niacin ineffective? Or did AIM-HIGH miss its target?

The AIM-HIGH trial (Atherothrombosis Intervention in Metabolic Syndrome With Low HDL/High Triglycerides: Impact on Global Health Outcomes) found, in an interim analysis, no cardiovascular benefit from taking extended-release niacin (Niaspan). In fact, there was a trend toward a greater risk of ischemic stroke, which did not reach statistical significance. But questions remain about this complex trial, which included intensive statin therapy in the active-treatment group and the control group.

Relationship of antihypertensive treatment to plasma markers of vascular inflammation and remodeling in the Comparison of Amlodipine versus Enalapril to Limit Occurrences of Thrombosis study

BACKGROUND

Antihypertensive agents lower the risk of cardiovascular events, but whether they affect pathways important in inflammation and plaque remodeling in atherosclerosis is uncertain. We assessed whether 2 commonly used antihypertensive agents affected plasma biomarkers reflecting specific inflammatory and remodeling processes over 2 years in the Comparison of Amlodipine versus Enalapril to Limit Occurrences of Thrombosis (CAMELOT) study.

METHODS

The study was a randomized controlled trial of 2 antihypertensives (amlodipine and enalapril) compared with placebo in patients with coronary artery disease and diastolic blood pressure less than 100 mm Hg. In 196 subjects who had baseline and 2-year intravascular coronary ultrasound examinations, we measured plasma interleukin 18, interleukin 1 receptor antagonist, matrix metalloproteinase 9, neopterin, and C-reactive protein. Results for both treatment groups were pooled and compared with placebo.

RESULTS

Antihypertensive treatment with either agent significantly lowered diastolic blood pressure (-4.7 vs placebo 1.3 mm Hg, P = .002) and progression of coronary atheroma (Δ percent atheroma volume 0.6 vs placebo 2.1, P = .031). Antihypertensive therapy did not affect plasma biomarkers of inflammation or plaque remodeling in the 135 subjects with baseline and 2-year biomarker samples. Progression in percent atheroma volume was significantly less in subjects taking statins at baseline (-2.5%, P = .0008).

CONCLUSIONS

In patients with coronary artery disease and well-controlled risk factors, antihypertensive therapy lowered blood pressure and progression of coronary atherosclerosis but did not affect plasma biomarkers of inflammation and remodeling. Antihypertensives may decrease atheroma progression by mechanisms other than those reflected by these plasma biomarkers.

Peroxisome proliferator-activated receptor (PPAR α/γ) agonists as a potential target to reduce cardiovascular risk in diabetes

The disappointing results of glucose lowering studies have highlighted the ongoing need to develop new therapeutic strategies to reduce cardiovascular risk in patients with type 2 diabetes. The presence of a range of metabolic abnormalities in diabetic patients presents a number of potential targets for therapeutic intervention. While modulation of peroxisome proliferator activated receptors (PPARs) represents an attractive approach, the results of studies of pharmacological agonists have been variable. The findings of these studies and rationale for development of dual PPAR-α/γ agonists will be reviewed.

Multiple risk factor intervention and progression of coronary atherosclerosis in patients with type 2 diabetes mellitus

BACKGROUND

Diabetic patients with coronary artery disease (CAD) demonstrate accelerated progression of coronary atherosclerosis. The impact of multiple risk factor intervention on disease progression has not been investigated.

DESIGN

We investigated 448 diabetic patients with angiographic CAD who underwent serial intravascular ultrasound imaging to monitor the change in atheroma burden in seven clinical trials.

METHODS

Disease progression was compared in patients stratified according to whether they achieved increasing numbers of treatment goals of individual risk factors (HbA1c <7.0%, LDL cholesterol <2.5 mmol/l, triglyceride <1.7 mmol/l, systolic blood pressure <130 mmHg, high sensitivity C-reactive protein <2.0 mg/l).

RESULTS

A high rate of established medical therapies was used in all patients (89% statins, 94% aspirin, 76% β-blockers, 66% ACE inhibitors, 66% metformin, 62% thiazolidinediones, 17% insulin). No differences were observed with regard to percentage atheroma volume (PAV) and total atheroma volume (TAV) at baseline. On serial evaluation, slowing of progression of PAV (p = 0.01) and TAV (p < 0.001) was observed with increasing numbers of risk factors achieving treatment goals. On multivariate analysis adjusting for baseline risk factors, increasing the number of factors meeting treatment goals continued to be associated with a beneficial impact on progression of PAV (p = 0.03) and TAV (p < 0.001).

CONCLUSION

The benefit of achieving optimal control of multiple risk factors underscores the need for modification of global risk in patients with diabetes.

The emerging role of plasma lipidomics in cardiovascular drug discovery

INTRODUCTION

With the rising global incidence of cardiovascular disease, the challenge for the pharmaceutical industry is to identify novel biomarkers that will allow not only for the development of the next generation of cardiometabolic therapeutics, but also to serve as a sensitive mechanism to monitor and predict drug efficacy and potential toxicity. The advent of an 'omics' (systems biological) approach has vast implications for future disease treatment and prevention. Lipidomics is the latest addition to the 'omics' family and is rapidly gaining attention due to the technological improvements in mass spectrometry, allowing for the characterization of large number of lipids (and their respective subclasses) in a short amount of time with relatively minimal preparation.

AREAS COVERED

The authors discuss the various techniques involved in plasma lipidomics as well as outline the role that lipidomics will play in phenotyping disease processes and corresponding therapeutic strategies. The article was formed through comprehensive Medline search of relevant publications in this area.

EXPERT OPINION

Despite the wealth of data that will emerge regarding the various lipid-molecular interactions and the functions of lipids within cells, a major challenge will be the parallel emergence of novel bioinformatics platforms in order to integrate this enormous data set with information generated from the emerging fields of genomics and proteomic analysis. Despite these challenges, lipidomics is likely to result in the reclassification of diseases from a molecular perspective and play a key role the eventuation of personalized medicine.

Effect of two intensive statin regimens on progression of coronary disease

BACKGROUND

Statins reduce adverse cardiovascular outcomes and slow the progression of coronary atherosclerosis in proportion to their ability to reduce low-density lipoprotein (LDL) cholesterol. However, few studies have either assessed the ability of intensive statin treatments to achieve disease regression or compared alternative approaches to maximal statin administration.

METHODS

We performed serial intravascular ultrasonography in 1039 patients with coronary disease, at baseline and after 104 weeks of treatment with either atorvastatin, 80 mg daily, or rosuvastatin, 40 mg daily, to compare the effect of these two intensive statin regimens on the progression of coronary atherosclerosis, as well as to assess their safety and side-effect profiles.

RESULTS

After 104 weeks of therapy, the rosuvastatin group had lower levels of LDL cholesterol than the atorvastatin group (62.6 vs. 70.2 mg per deciliter [1.62 vs. 1.82 mmol per liter], P<0.001), and higher levels of high-density lipoprotein (HDL) cholesterol (50.4 vs. 48.6 mg per deciliter [1.30 vs. 1.26 mmol per liter], P=0.01). The primary efficacy end point, percent atheroma volume (PAV), decreased by 0.99% (95% confidence interval [CI], -1.19 to -0.63) with atorvastatin and by 1.22% (95% CI, -1.52 to -0.90) with rosuvastatin (P=0.17). The effect on the secondary efficacy end point, normalized total atheroma volume (TAV), was more favorable with rosuvastatin than with atorvastatin: -6.39 mm(3) (95% CI, -7.52 to -5.12), as compared with -4.42 mm(3) (95% CI, -5.98 to -3.26) (P=0.01). Both agents induced regression in the majority of patients: 63.2% with atorvastatin and 68.5% with rosuvastatin for PAV (P=0.07) and 64.7% and 71.3%, respectively, for TAV (P=0.02). Both agents had acceptable side-effect profiles, with a low incidence of laboratory abnormalities and cardiovascular events.

CONCLUSIONS

Maximal doses of rosuvastatin and atorvastatin resulted in significant regression of coronary atherosclerosis. Despite the lower level of LDL cholesterol and the higher level of HDL cholesterol achieved with rosuvastatin, a similar degree of regression of PAV was observed in the two treatment groups. (Funded by AstraZeneca Pharmaceuticals; ClinicalTrials.gov number, NCT000620542.).

Risk prediction with serial myeloperoxidase monitoring in patients with acute chest pain

BACKGROUND

Although myeloperoxidase (MPO) monitoring is predictive for cardiovascular outcomes in suspected acute coronary syndromes, the value of serial testing is unknown.

METHODS

We investigated the relationship between serial MPO concentrations in 490 individuals with acute chest pain and incident major adverse cardiac events (MACE) during 6 months of follow-up. We measured MPO with the CardioMPO assay, and cardiac troponin I (cTnI), with the Abbott Architect assay.

RESULTS

Plasma MPO concentrations during the first 16 h were higher in individuals who experienced MACE. Higher MPO quartiles predicted a greater likelihood of 6-month MACE at baseline [OR (95% CI), 2.4 (1.4-4.1), P = 0.001 for highest vs lowest quartile] and all subsequent time points, with strongest predictive ability found in 16-h postbaseline samples [9.9 (4.7-20.9), P < 0.001 for highest vs lowest quartile]. MPO was predictive for MACE among individuals whose cTnI remained within reference intervals (<0.028 μg/L). The lowest rate of missed cases was found when MPO was <640 pmol/L at baseline and all other time points. Serial MPO monitoring predicted MACE risk better than baseline MPO measurements alone (c statistic 0.813 vs 0.602; P = 0.002), including in individuals whose cTnI remained within reference intervals (c statistic 0.903; P = 0.009). Combined serial cTnI and MPO testing improved accuracy for predicting 6-month MACE, reduced the number of missed MACE events from cTnI testing alone, and improved risk classification in 26.1% of patients.

CONCLUSIONS

MPO concentrations are predictive of outcome up to 16 h after presentation with chest pain and predict events missed by cTnI testing, supporting a potential role in rapid patient triage.

Effects of the CETP inhibitor evacetrapib administered as monotherapy or in combination with statins on HDL and LDL cholesterol: a randomized controlled trial

CONTEXT

Interest remains high in cholesteryl ester transfer protein (CETP) inhibitors as cardioprotective agents. Few studies have documented the efficacy and safety of CETP inhibitors in combination with commonly used statins.

OBJECTIVE

To examine the biochemical effects, safety, and tolerability of evacetrapib, as monotherapy and in combination with statins, in patients with dyslipidemia.

DESIGN, SETTING, AND PARTICIPANTS

Randomized controlled trial conducted among 398 patients with elevated low-density lipoprotein cholesterol (LDL-C) or low high-density lipoprotein cholesterol (HDL-C) levels from April 2010 to January 2011 at community and academic centers in the United States and Europe.

INTERVENTIONS

Following dietary lead-in, patients were randomly assigned to receive placebo (n = 38); evacetrapib monotherapy, 30 mg/d (n = 40), 100 mg/d (n = 39), or 500 mg/d (n = 42); or statin therapy (n = 239) (simvastatin, 40 mg/d; atorvastatin, 20 mg/d; or rosuvastatin, 10 mg/d) with or without evacetrapib, 100 mg/d, for 12 weeks.

MAIN OUTCOME MEASURES

The co-primary end points were percentage changes from baseline in HDL-C and LDL-C after 12 weeks of treatment.

RESULTS

The mean baseline HDL-C level was 55.1 (SD, 15.3) mg/dL and the mean baseline LDL-C level was 144.3 (SD, 26.6) mg/dL. As monotherapy, evacetrapib produced dose-dependent increases in HDL-C of 30.0 to 66.0 mg/dL (53.6% to 128.8%) compared with a decrease with placebo of -0.7 mg/dL (-3.0%; P < .001 for all compared with placebo) and decreases in LDL-C of -20.5 to -51.4 mg/dL (-13.6% to -35.9%) compared with an increase with placebo of 7.2 mg/dL (3.9%; P < .001 for all compared with placebo). In combination with statin therapy, evacetrapib, 100 mg/d, produced increases in HDL-C of 42.1 to 50.5 mg/dL (78.5% to 88.5%; P < .001 for all compared with statin monotherapy) and decreases in LDL-C of -67.1 to -75.8 mg/dL (-11.2% to -13.9%; P < .001 for all compared with statin monotherapy). Compared with evacetrapib monotherapy, the combination of statins and evacetrapib resulted in greater reductions in LDL-C (P <.001) but no greater increase in HDL-C (P =.39). Although the study was underpowered, no adverse effects were observed.

CONCLUSIONS

Compared with placebo or statin monotherapy, evacetrapib as monotherapy or in combination with statins increased HDL-C levels and decreased LDL-C levels. The effects on cardiovascular outcomes require further investigation.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01105975.

Coronary β2-adrenoreceptors mediate endothelium-dependent vasoreactivity in humans: novel insights from an in vivo intravascular ultrasound study

AIMS

The interaction between coronary β(2)-adrenoreceptors and segmental plaque burden is complex and poorly understood in humans. We aimed to validate intracoronary (IC) salbutamol as a novel endothelium-dependent vasodilator utilizing intravascular ultrasound (IVUS), and thus assess relationships between coronary β(2)-adrenoreceptors, regional plaque burden and segmental endothelial function.

METHODS AND RESULTS

In 29 patients with near-normal coronary angiograms, IVUS-upon-Doppler Flowire imaging protocols were performed. Protocol 1: incremental IC salbutamol (0.15, 0.30, 0.60 μg/min) infusions (15 patients, 103 segments); protocol 2: salbutamol (0.30 μg/min) infusion before and after IC administration of N(G)-monomethyl-L-arginine (L-NMMA) (10 patients, 82 segments). Vehicle infusions (IC dextrose) were performed in 4 patients (21 segments). Macrovascular response [% change segmental lumen volume (ΔSLV)] and plaque burden [per cent atheroma volume (PAV)] were studied in 5-mm coronary segments. Microvascular response [per cent change in coronary blood flow (ΔCBF)] was calculated following each infusion. Intracoronary salbutamol demonstrated significant dose-response ΔSLV and ΔCBF from baseline, respectively (0.15 μg/min: 3.5 ± 1.3%, 28 ± 14%, P = 0.04, P = NS; 0.30 μg/min: 5.5 ± 1.4%, 54 ± 17%, P = 0.001, P < 0.0001; 0.60 μg/min: 4.8 ± 1.6%, 66 ± 15%, P = 0.02, P < 0.0001), with ΔSLV responses further exemplified in low vs. high plaque burden groups. Salbutamol vasomotor responses were suppressed by l-NMMA, supporting nitric oxide-dependent mechanisms. Vehicle infusions resulted in no significant ΔSLV or ΔCBF. Multivariate analysis including conventional cardiovascular risk factors, PAV, segmental remodelling and plaque eccentricity indices identified PAV as the only significant predictor of a ΔSLV to IC salbutamol (coefficient -0.18, 95% CI -0.32 to -0.044, P = 0.015). Conclusions Intracoronary salbutamol is a novel endothelium-dependent epicardial and microvascular coronary vasodilator. Intravascular ultrasound-derived regional plaque burden is a major determinant of segmental coronary endothelial function.

Impact of statins on progression of atherosclerosis: rationale and design of SATURN (Study of Coronary Atheroma by InTravascular Ultrasound: effect of Rosuvastatin versus AtorvastatiN)

BACKGROUND

Previous imaging studies have demonstrated that the beneficial impact of high-dose statins on the progression of coronary atherosclerosis associates with their ability to lower levels of low-density lipoprotein cholesterol (LDL-C) and C-reactive protein (CRP) and to raise high-density lipoprotein cholesterol (HDL-C). The Study of Coronary Atheroma by InTravascular Ultrasound: Effect of Rosuvastatin versus AtorvastatiN (SATURN, NCT00620542) aims to compare the effects of high-dose atorvastatin and rosuvastatin on disease progression.

METHODS

A total of 1385 subjects with established coronary artery disease (CAD) on angiography were randomized to receive rosuvastatin 40 mg or atorvastatin 80 mg for 24 months. The primary efficacy parameter will be the nominal change in percent atheroma volume (PAV), determined by analysis of intravascular ultrasound (IVUS) images of matched coronary artery segments acquired at baseline and at 24-month follow-up. The effect of statin therapy on plasma lipids and inflammatory markers, and the incidence of clinical cardiovascular events will also be assessed. The study does not have the statistical power to directly compare the treatment groups with regard to clinical events.

CONCLUSION

Serial IVUS has emerged as a sensitive imaging modality to assess the impact of treatments on arterial structure. In this study, IVUS will be used to determine whether high-dose statins have different effects on plaque progression.

ETC-216 for coronary artery disease

INTRODUCTION

Increasing attention has focused on the role of high-density lipoprotein function as a target for cardiprotection. Apolipoprotein A-I(Milano) (AIM) involves a single amino-acid mutation of the major wild-type protein carried on high-density lipoprotein (HDL) particles. Early evidence of beneficial activities of AIM has stimulated support in its development as a potential therapy to reduce cardiovascular risk.

AREAS COVERED

The importance of HDL as a target and early data supporting the beneficial effects of AIM are reviewed. All clinical studies of AIM found in PubMed are reviewed.

EXPERT OPINION

ETC-216 represents a lipid-deplete form of HDL containing recombinant AIM. While early evidence suggests that administration of ETC-216 promotes rapid regression of coronary atherosclerosis, bringing this compound to clinical practice will require further trials that evaluate its impact on cardiovascular events.

Intravascular imaging of vulnerable coronary plaque: current and future concepts

Advances in coronary imaging are needed to enable the early detection of plaque segments considered to be 'vulnerable' for causing clinical events. Pathological studies have contributed to our current understanding of these vulnerable or unstable segments of plaque. Intravascular ultrasonography (IVUS) has provided insights into the morphology of atherosclerosis, the mediators of plaque progression and the factors associated with acute coronary syndrome (ACS). In addition, the demonstration of pancoronary arterial instability has highlighted that ACS involves a multifocal disease process. Various second-generation intravascular imaging technologies-employing advanced processing of ultrasound radiofrequency backscatter signals, light-based imaging, spectroscopic imaging and molecular targeting-possess inherent advantages for the identification of meaningful surrogates of plaque instability. The fusion of these imaging technologies within a single imaging catheter is likely to allow for greater synergism in image quality and early disease detection. However, natural-history studies to validate the use of these novel imaging tools for enhanced risk prediction are needed before these strategies can be incorporated into mainstream clinical practice.

Efficacy and safety of a novel oral inducer of apolipoprotein a-I synthesis in statin-treated patients with stable coronary artery disease a randomized controlled trial

OBJECTIVES

The purpose of this study was to investigate the safety, tolerability, and efficacy of RVX-208, the first oral agent designed to enhance apolipoprotein (apo) A-I synthesis.

BACKGROUND

No agent that selectively induces synthesis of apoA-I has reached an advanced stage of clinical development.

METHODS

A total of 299 statin-treated patients with coronary artery disease were treated with placebo or with RVX-208 at a dose of 50, 100, or 150 mg twice daily for 12 weeks. Changes in lipid-related biomarkers, in addition to safety and tolerability, of RVX-208 were investigated.

RESULTS

For each dose of RVX-208, individual pairwise comparisons of apoA-I changes with placebo, the primary end point, did not achieve statistical significance. However, treatment with RVX-208 was associated with a dose-dependent increase in apoA-I levels by up to 5.6% (p = 0.035 for trend). Administration of RVX-208 resulted in significant increases in levels of high-density lipoprotein cholesterol (HDL-C) ranging from 3.2% to 8.3% (p = 0.02), and large HDL particles increased by 11.1% to 21.1% (p = 0.003). ApoA-I levels increased rapidly from 8 to 12 weeks, suggesting that peak pharmacological effect has not been achieved by the end of the 12-week study. Transient and reversible elevations in liver transaminases >3 times the upper limit of normal were observed in 18 patients treated with RVX-208, with no associated increase in bilirubin levels.

CONCLUSIONS

Administration of RVX-208 for 12 weeks was associated with increases in apoA-I, HDL-C, and concentration of large HDL particles, consistent with facilitation of cholesterol mobilization. Maximal increases in apoA-I may require longer exposure. An increase in liver enzymes was observed with active treatment. (Clinical Trial for Dose Finding and Safety of RVX000222 in Subjects With Stable Coronary Artery Disease; NCT01058018).