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Although lipoprotein-associated phospholipase A₂ (Lp-PLA₂) levels are associated with cardiovascular events, Lp-PLA₂ is physically linked to LDL cholesterol (LDL-C). Whether measures of Lp-PLA₂ mass or activity continue to predict risk after LDL-C reduction by statin therapy is uncertain.

Lp-PLA₂ mass concentration and activity were evaluated at baseline and after treatment in the Justification for the Use of Statins in Prevention: an Intervention Trial Evaluating Rosuvastatin (JUPITER) trial comparing rosuvastatin 20 mg to placebo among 17 802 men and women without cardiovascular disease or diabetes at study entry. The relationships of Lp-PLA₂ mass and activity with risk of future vascular events were evaluated in the placebo and rosuvastatin groups.

Before randomization, levels of Lp-PLA₂ mass and activity correlated moderately with each other and with LDL-C. The magnitude of these correlations increased after statin therapy. Rosuvastatin reduced Lp-PLA₂ mass by 33.8%, Lp-PLA₂ activity by 33.2%, and LDL-C by 48.7% (all P < 0.0001). Among those study participants allocated to placebo, increasing quartiles of Lp-PLA₂ activity (P_trend = 0.04) but not Lp-PLA₂ mass (P_trend = 0.92) were associated with incident cardiovascular events after adjustment for LDL-C and conventional risk factors. Comparable analyses conducted among those allocated to rosuvastatin revealed no significant relationship between Lp-PLA₂ levels and subsequent vascular events. The ability of rosuvastatin to reduce vascular events was not significantly modified by baseline Lp-PLA₂ level.

Among JUPITER trial participants allocated to placebo, levels of Lp-PLA₂ activity, but not mass, were associated with cardiovascular risk. However, Lp-PLA₂ no longer predicted risk or modified clinical outcomes when participants were treated with rosuvastatin.

Fetuin-A is a hepatic secretory protein that inhibits arterial calcification in vitro. The association of fetuin-A with coronary arterial calcification (CAC) in the general population is uncertain.

Among 2457 community-living individuals without cardiovascular disease (CVD), we measured serum fetuin-A concentrations by ELISA and evaluated the cross-sectional association of fetuin-A with CAC prevalence (any vs none) and severity; on follow-up 3.2 years (median) later, we evaluated the association of fetuin-A with CAC incidence and progression.

The mean age was 62 (SD 10) years, and the mean fetuin-A concentration was 0.48 (0.10) g/L. At baseline, 1200 individuals (49%) had CAC, and 272 individuals developed CAC during follow-up. At baseline, there was a threshold effect at the lowest fetuin-A quartile with CAC prevalence. In models adjusted for demographics, traditional cardiovascular disease (CVD) risk factors and kidney function, the lowest fetuin-A quartile had 7% (95% CI 1%–13%; P = 0.04) greater CAC prevalence compared with quartiles 2–4. Similar associations were observed with CAC severity at baseline, but the association was more linear. Each SD (0.10 g/L) lower fetuin-A was associated with a 12% (95% CI 3%–21%; P = 0.01) greater CAC severity in adjusted models. There was no significant association of fetuin-A with CAC incidence or progression.

Fetuin-A is inversely associated with CAC severity among community-living individuals without CVD. Whether fetuin-A concentrations are associated with incident CVD event in the general population requires future study.

The CDC's Lipid Standardization Program established the chromotropic acid (CA) reference measurement procedure (RMP) as the accuracy base for standardization and metrological traceability for triglyceride testing. The CA RMP has several disadvantages, including lack of ruggedness. It uses obsolete instrumentation and hazardous reagents. To overcome these problems the CDC developed an isotope dilution GC-MS (ID-GC-MS) RMP for total glycerides in serum.

We diluted serum samples with Tris-HCl buffer solution and spiked 200-μL aliquots with [¹³C₃]-glycerol. These samples were incubated and hydrolyzed under basic conditions. The samples were dried, derivatized with acetic anhydride and pyridine, extracted with ethyl acetate, and analyzed by ID-GC-MS. Linearity, imprecision, and accuracy were evaluated by analyzing calibrator solutions, 10 serum pools, and a standard reference material (SRM 1951b).

The calibration response was linear for the range of calibrator concentrations examined (0–1.24 mmol/L) with a slope and intercept of 0.717 (95% CI, 0.7123–0.7225) and 0.3122 (95% CI, 0.3096–0.3140), respectively. The limit of detection was 14.8 μmol/L. The mean %CV for the sample set (serum pools and SRM) was 1.2%. The mean %bias from NIST isotope dilution MS values for SRM 1951b was 0.7%.

This ID-GC-MS RMP has the specificity and ruggedness to accurately quantify total glycerides in the serum pools used in the CDC's Lipid Standardization Program and demonstrates sufficiently acceptable agreement with the NIST primary RMP for total glyceride measurement.

Soluble intercellular adhesion molecule 1 (sICAM-1) is associated with endothelial dysfunction and clinical cardiovascular disease. We investigated the relationship of subclinical atherosclerosis with sICAM-1 concentration.

sICAM-1 concentration was assayed at year 15 of the Coronary Artery Risk Development in Young Adults (CARDIA) Study (black and white men and women, average age 40 years). We assessed progression of coronary artery calcification (CAC) through year 20 (n = 2378), and both carotid artery stenosis (n = 2432) and intima-media thickness (IMT) at year 20 (n = 2240).

Median sICAM-1 was 145.9 μg/L. Among a subgroup with advanced atherosclerotic plaque (either CAC or stenosis), IMT was 0.010 (95% CI 0.003–0.017 mm) higher per SD of sICAM-1 (44 μg/L) in a model adjusted for age, race, sex, clinic, smoking, exercise, body size, education, blood pressure, antihypertensive medication, plasma lipids, and cholesterol-lowering medication. With the same adjustment, the odds ratio (OR) for the presence of year-20 carotid artery stenosis per SD of sICAM-1 was 1.12 (95% CI 1.01–1.25, P < 0.04), whereas for occurrence of CAC progression the OR was 1.16 (1.04–1.31, P < 0.01). The associations with CAC and carotid stenosis were strongest in the top 20th of the sICAM-1 distribution.

sICAM-1 concentration may be an early biomarker that indicates changes in the artery wall that accompany atherosclerosis, as well as the presence of advanced plaque in the coronary and carotid arteries. This finding holds in people with low total burden of atherosclerosis, decades before the development of clinical CVD.

Growth differentiation factor 15 (GDF-15) is produced by cardiomyocytes and atherosclerotic lesions under stress conditions. Although higher circulating GDF-15 concentrations are associated with mortality across a spectrum of cardiovascular conditions, the relationship of GDF-15 with atherosclerosis and mortality in the general population remains undefined.

We measured plasma GDF-15 in 3219 participants of the Dallas Heart Study, a population sample of adults ages 30–65 years (55% women, 49% black). GDF-15 was analyzed in prespecified categories (<1200; 1200–1799; and ≥1800 ng/L) and continuously. End points included prevalent coronary artery calcium (CAC >10 Agatston units), increased CAC (CAC ≥100 Agatston units) by electron beam computed tomography, and mortality through a median 7.3 years of follow-up (120 deaths, 48 cardiovascular deaths).

Increasing GDF-15 associated with older age, black race, hypertension, diabetes, smoking, left ventricular (LV) mass/body surface area, and worse renal function (P < 0.0001 for each). In multivariable models adjusted for traditional risk factors, renal function, and LV mass/body surface area, GDF-15 ≥1800 ng/L was associated with CAC >10 (odds ratio 2.1; 95% CI 1.2–3.7; P = 0.01), CAC ≥100 (odds ratio 2.6; 95% CI 1.4–4.9; P = 0.002), all-cause mortality (hazard ratio 3.5; 95% CI 2.1–5.9, P < 0.0001), and cardiovascular mortality (hazard ratio 2.5; 95% CI 1.1–5.8, P = 0.03). Adding log GDF-15 to fully adjusted models modestly improved the c statistic (P = 0.025), the integrated discrimination index (0.028; P < 0.0001) and the category-less net reclassification index (0.42; P = 0.002). These findings remained significant with further adjustment for high-sensitivity C-reactive protein, N-terminal pro–B-type natriuretic peptide, and cardiac troponin T.

GDF-15 is independently associated with subclinical coronary atherosclerosis and mortality, and its potential role for risk stratification in the general population merits further evaluation.

Although statin therapy is known to increase concentrations of PCSK9, whether this effect is related to the magnitude of LDL reduction is uncertain. This study was undertaken to understand the extent of this effect and examine the relationship between PCSK9 and LDL cholesterol (LDL-C) reduction.

We measured plasma PCSK9 concentrations by ELISA at baseline and at 1 year in 500 men and 500 women participating in the Justification for Use of Statins in Prevention: an Intervention Trial Evaluating Rosuvastatin (JUPITER) trial that randomly allocated participants to rosuvastatin 20 mg daily or placebo. We also evaluated rs11591147, a single nucleotide polymorphism known to have an impact on plasma PCSK9 concentrations.

At baseline, median (interquartile range) PCSK9 concentrations were higher in women [73 (62–90)] ng/mL than in men [69 (57–81) ng/mL] (P < 0.005). During 1 year, there was no change in PCSK9 concentrations in the placebo arm, suggesting stability in time. In contrast, the rosuvastatin increased PCSK9 by 35% in women [101 (82–117) ng/mL] and 28% in men [89 (71–109) ng/mL] (P < 0.0001). Among those allocated to rosuvastatin, greater reductions in LDL-C were associated with greater increases in PCSK9 on both absolute and relative scales (r = –0.15, P < 0.0005). Furthermore PCSK9 (rs11591147) did not alter the magnitude of LDL-C reduction associated with rosuvastatin use.

In this randomized trial, rosuvastatin increased plasma concentration of PCSK9 in proportion to the magnitude of LDL-C reduction; the LDL-C response to statin could not be inferred by PCSK9 concentrations.

We evaluated the predictive ability of cystatin C and creatinine-based estimations of glomerular filtration rate (eGFR), including the Chronic Kidney Disease–Epidemiology (CKD-EPI) equation, in acute coronary syndrome (ACS) patients with (STE-ACS) or without (NSTE-ACS) ST elevation in a large contemporary ACS population.

Concentrations of cystatin C and creatinine, as well as eGFR at randomization, were measured in 16 401 patients in the Platelet Inhibition and Patient Outcomes (PLATO) study and evaluated as predictors of the composite end point of cardiovascular death or myocardial infarction within 1 year. Two Cox proportional hazards models were used, the first adjusting for clinical characteristics and the second for clinical characteristics plus the biomarkers N-terminal pro–B-type natriuretic peptide, troponin I, and C-reactive protein.

The median cystatin C value was 0.83 mg/L. Increasing quartiles of cystatin C were strongly associated with poor outcome (6.9%, 7.1%, 9.5%, and 16.2%). The fully adjusted hazard ratios per SD of cystatin C in the NSTE-ACS and STE-ACS populations were 1.12 (95% CI 1.04–1.20) (n = 8053) and 1.06 (95% CI 0.97–1.17) (n = 5278), respectively. There was no significant relationship of cystatin C with type of ACS (STE or NSTE). c Statistics ranged from 0.6923 (cystatin C) to 0.6941 (CKD-EPI).

Cystatin C concentration contributes independently in predicting the risk of cardiovascular death or myocardial infarction in NSTE-ACS, with no interaction by type of ACS. CKD-EPI exhibited the largest predictive value of all renal markers. Nevertheless, the additive predictive value of cystatin C or creatinine-based eGFR measures in the unselected ACS patient is small.

Measuring circulating cardiac troponin using novel sensitive assays has revealed that even minute elevations are associated with increased mortality in patients with coronary artery disease or even in the general population. Less well defined, however, is the incremental value of measuring circulating cardiac troponin I (cTnI) by a sensitive assay for risk assessment in primary prevention.

We measured circulating concentrations of cTnI, N-terminal pro–B-type natriuretic peptide (NT-proBNP), and high-sensitivity C-reactive protein (hsCRP) in 5388 individuals free of known cardiovascular disease recruited into the DETECT study, a prospective longitudinal population-based cohort study. We determined the prognostic implications for incident major adverse cardiovascular events (MACE) during 5 years of follow-up.

Circulating cTnI was detectable in 19% of the subjects. Increased cTnI concentrations were associated with established risk factors for atherosclerosis and demonstrated a graded relationship with all-cause mortality and incident MACE during 5-year follow-up. A single measurement of cTnI significantly improved risk prediction over established risk factors, and also added prognostic information, when adjusted for serum concentrations of NT-proBNP and hsCRP.

Minute increases in cTnI are associated with increased mortality and incident MACE in a large primary prevention cohort and, thus, identify contributors to cardiovascular risk not fully captured by traditional risk factor assessment.