Determinants of plasma vitamin D levels in patients with acute coronary syndromes.

BACKGROUND: Vitamin D is implicated in various biological functions ranging from cellular proliferation to immunity. Vitamin D deficiency is associated with an increased risk of several diseases including coronary atherosclerosis. MATERIALS AND METHODS: We measured plasma 25(OH)D3 level in 224 patients with acute coronary syndromes (ACS) and 209 control individuals by ELISA. We genotyped the study populations for 11 single nucleotide polymorphisms (SNPs) in seven genes involved in vitamin D biosynthesis and metabolism by 5' nuclease assays. RESULTS: The mean and median plasma 25(OH)D3 levels were not significantly different between patients with ACS and controls (median: 22·06 vs. 22·24 ng mL(-1) , respectively, P = 0·618). Plasma 25(OH)D3 level was < 20 ng mL(-1) in 175/433 (40%) and < 30 ng mL(-1) in 333/433 (77%) participants. Only four individuals had plasma 25(OH)D3 levels of above 60 ng mL(-1) . African-American and Hispanic populations, women and those with diabetes mellitus had significantly lower plasma 25(OH)D3 levels. In multivariable regression analysis, age, sex, diabetes mellitus, body weight, rs2762933 (CYP24A1) and rs6055987 (PLCB1) SNPs were independent predictors of plasma 25(OH)D3 level in the Caucasian population. CONCLUSIONS: We found no difference in mean plasma vitamin D levels between patients with ACS and controls. Differences in population characteristics between the two study groups including medications use and the lack of data on vitamin D, calcium and multivitamin supplements intake as well as the relatively small sample size of the populations could confound the results. Ethnic background, sex, age, body weight and SNPs in CYP24A1 and PLCB1 were independent determinants of plasma vitamin D levels.

Heparin-associated anti-Xa activity and platelet-derived prothrombotic and proinflammatory biomarkers in moderate to high-risk patients with acute coronary syndrome.

Heparin compounds, to include fractionated and unfractionated preparations, exert both antithrombotic and antiinflammatory effects through combined inhibition of factor Xa and thrombin. The contribution of modulated platelet activity in vivo is less clearly defined. The SYNERGY library was a prospectively designed repository for candidate clinical, hemostatic, platelet, and molecular biomarkers from patients participating in SYNERGY--a large-scale, randomized clinical trial evaluating the comparative benefits of unfractionated heparin (UFH) and enoxaparin in high-risk patients with acute coronary syndrome (ACS). Samples were collected from 201 patients enrolled at 26 experienced, participating sites and shipped to established core laboratories for analysis of platelet, endothelium-derived, inflammatory and coagulation activity biomarkers. Tissue factor pathway inhibitor (TFPI)--a vascular endothelial cell-derived factor Xa regulatory protein-correlated directly with plasma anti-Xa activity (unadjusted: r = 0.23, P < 0.0001; adjusted: ß = 0.10; P = 0.001), as did TFPI-fXa complexes (unadjusted: r = 0.34, P < 0.0001; adjusted: ß = 0.38; P = < 0.0001). In contrast, there was a direct and inverse relationship between anti-Xa activity and two platelet-derived biomarkers-plasminogen activator inhibitor-1 (unadjusted: r = -0.18, P = 0.0012; adjusted: ß = -0.10; P = 0.021) and soluble CD40 ligand (unadjusted: r = -0.11, P = 0.05; adjusted: ß = -0.13; P = 0.049). All measured analyte relationships persisted after adjustment for age, creatinine clearance, weight, sex, and duration of treatment. Differences in biomarkers between patients receiving UFH and those randomized to enoxaparin were not observed. The ability of heparin compounds to affect the prothrombotic and proinflammatory states which characterize ACS may involve factor Xa-related modulation of platelet activation and expression. Whether this potentially beneficial effect is direct or indirect and achieved, at least in part, through the release of endothelial cell-derived coagulation regulatory proteins will require further investigation.

Comparison of site-reported and core laboratory-reported creatine kinase-MB values in non-ST-segment elevation acute coronary syndrome (from the international trial SYNERGY).

The effect of nonstandardized creatine kinase (CK)-MB assays on the assessment of myocardial infarction (MI) end points in multicenter international trials has not been evaluated. We compared the site-reported and corresponding core laboratory CK-MB measures from 5 countries participating in the Superior Yield of the New Strategy of Enoxaparin, Revascularization, and Glycoprotein IIb/IIIa Inhibitors (SYNERGY) trial. Samples for CK-MB were collected locally, with corresponding samples sent to a core laboratory at enrollment and after recurrent ischemic events, percutaneous coronary intervention, or coronary artery bypass grafting. The measured values were compared to the reported assay upper limits of normal (ULN) used at the site (or core laboratory for the core laboratory samples). The CK-MB results were available locally and from the core laboratory for 913 patients, constituting 4,693 time-matched laboratory values. The agreement between the core and site laboratory CK-MB/ULN ratio was moderate (concordance correlation coefficient 0.45) and varied considerably by geographic location and site. The CK-MB values were elevated (>or=2 times the ULN) by the core laboratory but normal (<2 times the ULN) by local standards in 708 instances (15%). There were 162 MI end points according to the core laboratory values versus 91 MI end points using the site-reported CK-MB data (kappa statistic 0.48). Compared with patients with no MI by the core or site laboratory values, patients with MI, as determined by both the core and the site laboratories, had significantly lower unadjusted 1-year survival rates (80.6% vs 93.5%, p <0.0001). Patients with MI, as determined by the core laboratory but not by the site laboratory, showed a trend toward a lower 1-year survival rate (89.8% vs 93.5%, p = 0.20). In conclusion, a substantial variation in CK-MB ratios and MI outcomes between the site and core laboratory data was observed in the SYNERGY trial. More MI outcomes were identified by the core laboratory, and patients with MI as defined by core laboratory data had lower 1-year survival, making these events potentially clinically important.

Rationale and design of the Acute Study of Clinical Effectiveness of Nesiritide in Decompensated Heart Failure Trial (ASCEND-HF).

BACKGROUND: Acute decompensated heart failure (ADHF) is a major public health burden with significant mortality and morbidity. Nesiritide is a recombinantly produced intravenous formulation of human B-type natriuretic peptide that promotes vasodilation and increases salt and water excretion, which results in reduced cardiac filling pressures. Prior studies have shown that dyspnea is improved in patients with ADHF 3 hours after nesiritide infusion with significant dose-related reductions in cardiac filling pressures and systemic vascular resistance without significant arrhythmias. However, the effect of nesiritide on dyspnea at 6 or 24 hours is unknown, and no clinical outcome trials have been done to provide a reliable estimate of the effect of nesiritide on morbidity and mortality. METHODS: The Acute Study of Clinical Effectiveness of Nesiritide in Decompensated Heart Failure trial (ASCEND-HF) is a phase III study evaluating the efficacy and safety of nesiritide in patients with ADHF. Patients hospitalized for hear failure will be randomly assigned to receive either intravenous nesiritide or matching placebo for 24 hours to 7 days. The 2 coprimary end points are (1) assessment of acute dyspnea at 6 or 24 hours and (2) death or rehospitalization for hear failure within 30 days. A total of 7,000 patients will be enrolled worldwide between 2007 and 2010. CONCLUSIONS: The data from the ASCEND-HF trial will establish whether nesiritide safely improves acute dyspnea as well as morbidity and mortality at 30 days.

Integrating ancillary studies in a large clinical trial: the design and rationale of the APEX library.

The APEX library was a coordinated and integrated set of ancillary analyses and substudies that were a part of the large APEX-AMI trial. The library included electrocardiogram, angiographic, blood biomarker, genetics, and MRI components. Operationally, the goals and administration of the APEX library were developed concurrently with the design of the parent trial. The goal recruitment in the library was met due to this approach. These data will provide important insights into the pathobiology of acute myocardial infarction and the relationships between inflammation, thrombosis, genetics, and classic clinical markers from angiograms, electrocardiograms, and patient demographics. In conclusion, the APEX library is an example of successful collaboration among academic trial leaders, site investigators, and pharmaceutical sponsors. The operational paradigm of this effort should be considered in future investigations so that important advances in clinical care of disease can be realized efficiently.

High-risk patients with acute coronary syndromes treated with low-molecular-weight or unfractionated heparin: outcomes at 6 months and 1 year in the SYNERGY trial.

CONTEXT: The SYNERGY trial comparing enoxaparin and unfractionated heparin in high-risk patients with acute coronary syndromes (ACS) showed that enoxaparin was not inferior to unfractionated heparin in reducing death or nonfatal myocardial infarction (MI) at 30 days. OBJECTIVE: To evaluate continued risk in this patient cohort through 6-month and 1-year follow-up. DESIGN, SETTING, AND PATIENTS: Overall, 9978 patients were randomized from August 2001 through December 2003 in 487 hospitals in 12 countries. Patients were followed up for 6 months and for 1 year. MAIN OUTCOME MEASURES: Six-month outcomes were death, nonfatal MI, revascularization procedures, stroke, and site-investigator-reported need for rehospitalization; 1-year outcome was all-cause death. RESULTS: Six-month and 1-year follow-up data were available for 9957 (99.8%) and 9608 (96.3%) of 9978 patients, respectively; 541 patients (5.4%) had died at 6 months and 739 (7.4%) at 1 year. Death or nonfatal MI at 6 months occurred in 872 patients receiving enoxaparin (17.6%) vs 884 receiving unfractionated heparin (17.8%) (hazard ratio [HR], 0.98; 95% confidence interval [CI], 0.89-1.07; P = .65). In the subgroup of patients receiving consistent therapy, ie, only enoxaparin or unfractionated heparin during the index hospitalization (n = 6138), a reduction in death or nonfatal MI with enoxaparin was maintained at 180 days (HR, 0.85; 95% CI, 0.75-0.95; P = .006). Rehospitalization within 180 days occurred in 858 patients receiving enoxaparin (17.9%) and 911 receiving unfractionated heparin (19.0%) (HR, 0.94; 95% CI, 0.85-1.03; P = .17). One-year all-cause death rates were similar in the 2 treatment groups (380/4974 [7.6%] for enoxaparin vs 359/4948 [7.3%] for unfractionated heparin; HR, 1.06; 95% CI, 0.92-1.22; P = .44). One-year death rates in patients receiving consistent therapy were also similar (251/3386 [7.4%] for enoxaparin vs 213/2720 [7.8%] for unfractionated heparin; HR, 0.95; 95% CI, 0.79-1.14; P = .55). CONCLUSIONS: In the SYNERGY trial, patients continued to experience adverse cardiac events through long-term follow-up. The effect of enoxaparin on death or MI compared with that of unfractionated heparin at 6 months was similar to that observed at 30 days in the overall trial and in the consistent-therapy group. One-year death rates were also similar in both groups. High-risk patients with ACS remain susceptible to continued cardiac events despite aggressive therapies.ClinicalTrials.gov Identifier: NCT00043784.

Coordinated series of studies to evaluate characteristics and mechanisms of acute coronary syndromes in high-risk patients randomly assigned to enoxaparin or unfractionated heparin: design and rationale of the SYNERGY Library.

Clinical trials and accompanying substudies in patients with acute coronary syndromes (ACS) have over the last several years yielded a wealth of knowledge about the pathophysiology and management of this high-risk condition. The Superior Yield of the New strategy of Enoxaparin, Revascularization, and GlYcoprotein IIb/IIIa inhibitors (SYNERGY) trial is a large-scale, randomized, controlled trial evaluating the effect of enoxaparin and unfractionated heparin on death and myocardial infarction in high-risk patients presenting with non-ST-segment elevation ACS. The SYNERGY Library has been designed as a coordinated series of investigations with simultaneous data acquisition on the same cohort of approximately 500 SYNERGY patients at 60 centers in North America. Specifically, electrocardiograms, coronary arteriograms, inflammatory markers, coagulation studies, and genetic samples will be collected and processed at core laboratory facilities, and the results will be stored in a central repository. This novel strategy for substudy investigation is unprecedented in cardiovascular clinical trials. The goal is to gain significant understanding about this patient population, discover new principles of pathophysiology, identify novel pharmacologic targets, and streamline further drug development. It is hoped that the SYNERGY Library will serve as a model for future substudy design to maximize academic insight within the framework of a large-scale, multicenter trial.