Genome-wide and gene-centric analyses of circulating myeloperoxidase levels in the charge and care consortia.

Increased systemic levels of myeloperoxidase (MPO) are associated with the risk of coronary artery disease (CAD). To identify the genetic factors that are associated with circulating MPO levels, we carried out a genome-wide association study (GWAS) and a gene-centric analysis in subjects of European ancestry and African Americans (AAs). A locus on chromosome 1q31.1 containing the complement factor H (CFH) gene was strongly associated with serum MPO levels in 9305 subjects of European ancestry (lead SNP rs800292; P = 4.89 × 10(-41)) and in 1690 AA subjects (rs505102; P = 1.05 × 10(-8)). Gene-centric analyses in 8335 subjects of European ancestry additionally identified two rare MPO coding sequence variants that were associated with serum MPO levels (rs28730837, P = 5.21 × 10(-12); rs35897051, P = 3.32 × 10(-8)). A GWAS for plasma MPO levels in 9260 European ancestry subjects identified a chromosome 17q22 region near MPO that was significantly associated (lead SNP rs6503905; P = 2.94 × 10(-12)), but the CFH locus did not exhibit evidence of association with plasma MPO levels. Functional analyses revealed that rs800292 was associated with levels of complement proteins in serum. Variants at chromosome 17q22 also had pleiotropic cis effects on gene expression. In a case-control analysis of ∼80 000 subjects from CARDIoGRAM, none of the identified single-nucleotide polymorphisms (SNPs) were associated with CAD. These results suggest that distinct genetic factors regulate serum and plasma MPO levels, which may have relevance for various acute and chronic inflammatory disorders. The clinical implications for CAD and a better understanding of the functional basis for the association of CFH and MPO variants with circulating MPO levels require further study.

MR-proANP and MR-proADM for risk stratification of patients with acute chest pain.

OBJECTIVE: To evaluate mid-regional pro-adrenomedullin (MR-proADM) and mid-regional pro-atrial natriuretic peptide (MR-proANP) as prognostic biomarkers in a representative 'real world' cohort of patients with suspected acute coronary syndrome (ACS). DESIGN: Prospective observational multicentre cohort study. SETTING: Chest pain units of three major hospitals in Germany from 2007 to 2008. PATIENTS: Patients presenting with signs and symptoms suggestive of an ACS. MAIN OUTCOME MEASURES: Primary end point was death or non-fatal myocardial infarction (MI), and secondary end point was death, non-fatal MI, stroke, need for coronary revascularisation, and hospital admission for cardiovascular cause or acute heart failure within 6 months after enrolment. RESULTS: 1386 patients (male/female = 920/466) were enrolled. Follow-up information was available for 97.8% of patients (median follow-up time 183 days). Forty-three patients reached the primary end point, and 132 the secondary end point. Patients who reached a primary end point had significantly higher MR-proANP (271 vs 101 pmol/l, p < 0.001) and MR-proADM (0.86 vs 0.59 nmol/l, p < 0.001) concentrations than those who did not. Cox regression analysis revealed a 2.55-fold risk of death or non fatal MI (95% CI 1.48 to 2.46, p < 0.001) for an increment of the log-transformed MR-proANP concentration by 1 SD after adjustment for cardiovascular risk factors, and a 1.91-fold risk (95% CI 1.48 to 2.46, p < 0.001) for MR-proADM. Both peptides could result in significant reclassification of patients when added to the Global Registry of Acute Coronary Events risk score, with an overall net reclassification improvement of 41.2% for MR-proADM and 35.7% for MR-proANP. CONCLUSIONS: MR-proADM and MR-proANP are predictors of future cardiovascular events in patients presenting with acute chest pain and might facilitate the choice of treatment in those patients complementary to established risk scores.

Sex differences in early carotid atherosclerosis (from the community-based Gutenberg-Heart Study).

The objectives of this study were to describe gender differences in intima-media thickness (IMT) in a community-based population study and to define normal IMT values for healthy men and women. In total, 4,814 participants (aged 35 to 74 years; 2,433 men, 2,381 women) from the Gutenberg-Heart Study (GHS) were included. IMT was measured at both common carotid arteries using an edge detection system. Median IMT was 0.62 mm (25th percentile 0.55, 75th percentile 0.70) in women and 0.65 mm (25th percentile 0.57, 75th percentile 0.75) in men and was significantly associated with age (p <0.0001). On multivariate analysis, advanced age, smoking, and arterial hypertension were positively associated with higher IMT in men and women. A subgroup of 1,025 subjects without cardiovascular risk factors or previous cardiovascular disease was analyzed to define normal IMT values. Nomograms were calculated according to age and gender. For each age group, IMT >95th percentile was defined as abnormal. In this subgroup, gender differences in IMT became nonsignificant at older ages. At the age of 35 years, IMT was 0.71 mm in men and 0.61 mm in women at the 95th percentile. In comparison, at the age of 74 years, IMT at the 95th percentile was 0.90 mm in men and 0.89 mm in women. In conclusion, men had higher carotid IMT than women, but predictors of early carotid atherosclerosis were similar across genders. In young subjects without cardiovascular risk factors, normal values for IMT were lower in women compared with men. In contrast, in older subjects, gender differences in IMT became nonsignificant.

Multiple marker approach to risk stratification in patients with stable coronary artery disease.

AIMS: multimarker approaches for risk prediction in coronary artery disease have remained inconsistent. We assessed multiple biomarkers representing distinct pathophysiological pathways in relation to cardiovascular events in stable angina. METHODS AND RESULTS: we investigated 12 biomarkers reflecting inflammation [C-reactive protein, growth-differentiation factor (GDF)-15, neopterin], lipid metabolism (apolipoproteins AI, B100), renal function (cystatin C, serum creatinine), and cardiovascular function and remodelling [copeptin, C-terminal-pro-endothelin-1, mid-regional-pro-adrenomedullin (MR-proADM), mid-regional-pro-atrial natriuretic peptide (MR-proANP), N-terminal-pro-B-type natriuretic peptide (Nt-proBNP)] in 1781 stable angina patients in relation to non-fatal myocardial infarction and cardiovascular death (n = 137) over 3.6 years. Using Cox proportional hazards models and C-indices, the strongest association with outcome for log-transformed biomarkers in multivariable-adjusted analyses was observed for Nt-proBNP [hazard ratio (HR) for one standard deviation increase 1.65, 95% confidence interval (CI) 1.28-2.13, C-index 0.686], GDF-15 (HR 1.59, 95% CI 1.25-2.02, C-index 0.681), MR-proANP (HR 1.46, 95% CI 1.14-1.87, C-index 0.673), cystatin C (HR 1.39, 95% CI 1.10-1.75, C-index 0.671), and MR-proADM (HR 1.63, 95% CI 1.21-2.20, C-index 0.668). Each of these top single markers and their combination (C-index 0.690) added predictive information beyond the baseline model consisting of the classical risk factors assessed by C-index and led to substantial reclassification (P-integrated discrimination improvement <0.05). CONCLUSION: comparative analysis of 12 biomarkers revealed Nt-proBNP, GDF-15, MR-proANP, cystatin C, and MR-proADM as the strongest predictors of cardiovascular outcome in stable angina. All five biomarkers taken separately offered incremental predictive ability over established risk factors. Combination of the single markers slightly improved model fit but did not enhance risk prediction from a clinical perspective.

Copeptin improves early diagnosis of acute myocardial infarction.

OBJECTIVES: Early identification of myocardial infarction in chest pain patients is crucial to identify patients at risk and to maintain a fast treatment initiation. BACKGROUND: The aim of the current investigation is to test whether determination of copeptin, an indirect marker for arginin-vasopressin, adds diagnostic information to cardiac troponin in early evaluation of patients with suspected myocardial infarction. METHODS: Between January 2007 and July 2008, patients with suspected acute coronary syndrome were consecutively enrolled in this multicenter study. Copeptin, troponin T (TnT), myoglobin, and creatine kinase-myocardial band were determined at admission and after 3 and 6 h. RESULTS: Of 1,386 (66.4% male) enrolled patients, 299 (21.6%) had the discharge diagnosis of acute myocardial infarction, 184 (13.3%) presented with unstable angina, and in 903 (65.2%) an acute coronary syndrome could be excluded. Combined measurement of copeptin and TnT on admission improved the c-statistic from 0.84 for TnT alone to 0.93 in the overall population and from 0.77 to 0.9 in patients presenting within 3 h after chest pain onset (CPO) (p < 0.001). In this group the combination of copeptin with a conventional TnT provided a negative predictive value of 92.4%. CONCLUSIONS: In triage of chest pain patients, determination of copeptin in addition to troponin improves diagnostic performance, especially early after CPO. Combined determination of troponin and copeptin provides a remarkable negative predictive value virtually independent of CPO time and therefore aids in early and safe rule-out of myocardial infarction.

Contribution of 30 biomarkers to 10-year cardiovascular risk estimation in 2 population cohorts: the MONICA, risk, genetics, archiving, and monograph (MORGAM) biomarker project.

BACKGROUND: Cardiovascular risk estimation by novel biomarkers needs assessment in disease-free population cohorts, followed up for incident cardiovascular events, assaying the serum and plasma archived at baseline. We report results from 2 cohorts in such a continuing study. METHODS AND RESULTS: Thirty novel biomarkers from different pathophysiological pathways were evaluated in 7915 men and women of the FINRISK97 population cohort with 538 incident cardiovascular events at 10 years (fatal or nonfatal coronary or stroke events), from which a biomarker score was developed and then validated in the 2551 men of the Belfast Prospective Epidemiological Study of Myocardial Infarction (PRIME) cohort (260 events). No single biomarker consistently improved risk estimation in FINRISK97 men and FINRISK97 women and the Belfast PRIME Men cohort after allowing for confounding factors; however, the strongest associations (with hazard ratio per SD in FINRISK97 men) were found for N-terminal pro-brain natriuretic peptide (1.23), C-reactive protein (1.23), B-type natriuretic peptide (1.19), and sensitive troponin I (1.18). A biomarker score was developed from the FINRISK97 cohort with the use of regression coefficients and lasso methods, with selection of troponin I, C-reactive protein, and N-terminal pro-brain natriuretic peptide. Adding this score to a conventional risk factor model in the Belfast PRIME Men cohort validated it by improved c-statistics (P=0.004) and integrated discrimination (P<0.0001) and led to significant reclassification of individuals into risk categories (P=0.0008). CONCLUSIONS: The addition of a biomarker score including N-terminal pro-brain natriuretic peptide, C-reactive protein, and sensitive troponin I to a conventional risk model improved 10-year risk estimation for cardiovascular events in 2 middle-aged European populations. Further validation is needed in other populations and age groups.

Sensitive troponin I assay in early diagnosis of acute myocardial infarction.

BACKGROUND: Cardiac troponin testing is central to the diagnosis of acute myocardial infarction. We evaluated a sensitive troponin I assay for the early diagnosis and risk stratification of myocardial infarction. METHODS: In a multicenter study, we determined levels of troponin I as assessed by a sensitive assay, troponin T, and traditional myocardial necrosis markers in 1818 consecutive patients with suspected acute myocardial infarction, on admission and 3 hours and 6 hours after admission. RESULTS: For samples obtained on admission, the diagnostic accuracy was highest with the sensitive troponin I assay (area under the receiver-operating-characteristic curve [AUC], 0.96), as compared with the troponin T assay (AUC, 0.85) and traditional myocardial necrosis markers. With the use of the sensitive troponin I assay (cutoff value, 0.04 ng per milliliter) on admission, the clinical sensitivity was 90.7%, and the specificity was 90.2%. The diagnostic accuracy was virtually identical in baseline and serial samples, regardless of the time of chest-pain onset. In patients presenting within 3 hours after chest-pain onset, a single sensitive troponin I assay had a negative predictive value of 84.1% and a positive predictive value of 86.7%; these findings predicted a 30% rise in the troponin I level within 6 hours. A troponin I level of more than 0.04 ng per milliliter was independently associated with an increased risk of an adverse outcome at 30 days (hazard ratio, 1.96; 95% confidence interval, 1.27 to 3.05; P=0.003). CONCLUSIONS: The use of a sensitive assay for troponin I improves early diagnosis of acute myocardial infarction and risk stratification, regardless of the time of chest-pain onset.

Cystatin C and cardiovascular mortality in patients with coronary artery disease and normal or mildly reduced kidney function: results from the AtheroGene study.

AIMS: Chronic kidney disease is associated with increased risk of cardiovascular disease. Cystatin C is a promising marker to reliably mirror renal function. The role of cystatin C in patients with coronary artery disease (CAD) and normal or mildly reduced kidney function is the subject of current investigation. METHODS AND RESULTS: In 2162 patients, over the whole spectrum of CAD, baseline cystatin C concentrations were measured. Patients with an estimated glomerular filtration rate of < or =60 mL/min per 1.73 m(2) (n = 295) were excluded. In patients with complete follow-up information (n = 1827), 66 cardiovascular deaths were registered during a median follow-up of 3.65 years. Logarithmically transformed, standardized cystatin C was associated with cardiovascular death [hazard ratio: 1.94, 95% confidence interval (CI): 1.59-2.37, P < 0.001]. A potential threshold effect was observed; patients in the upper quartile had a 3.87-fold (95% CI: 2.33-6.42; P < 0.001) risk of mortality compared with the pooled lower quartiles. This risk association remained robust after adjustment for potential confounders including classical risk factors and N-terminal pro B-type natriuretic peptide. Serum creatinine was not associated with the outcome in this group of patients with normal renal function. CONCLUSION: Results of this prospective study show that cystatin C is a potent predictor of cardiovascular mortality beyond classical risk factors in patients with CAD and normal or mildly reduced kidney function.

Direct measurement of left ventricular outflow tract by transthoracic real-time 3D-echocardiography increases accuracy in assessment of aortic valve stenosis.

BACKGROUND: Evaluation of aortic valve stenosis is a major clinical application of echocardiography. The widely employed continuity equation requires determination of the left ventricular outflow tract (LVOT) area. We aimed at testing whether direct area measurement in a volume data set is superior to conventional calculation from the LVOT diameter. METHODS: We performed LVOT measurement in 20 normal subjects and 83 patients with moderate to severe aortic stenosis with a transthoracic real-time three-dimensional echocardiography (3D-TTE) technique in two systolic frames. The off-line 3D-evaluation allows full choice of section planes within the acquired volume data set. The aortic valve area was calculated from systolic LVOT areas. These results were compared to area values obtained by M-mode LVOT-diameters (area=pi(*)(d/2)(2)). In addition, the calculated aortic valve orifices were compared to invasive measurements or direct planimetry in the transthoracic or transesophageal examination. RESULTS: Two independent observers found a reduction in LVOT area during systole (p<0.001). Often a more ellipsoid-like shaped LVOT resulted at end-systole which was shown by a reduction (p<0.001) of the LVOT longitudinal to oblique axis ratio. 3D-TTE determination of aortic valve orifice areas (mean difference: -0.04+/-0.09 cm(2)) showed a lesser deviation from the invasively or planimetrically measured areas than conventionally calculated LVOT areas (mean difference: -0.1+/-0.1 cm(2)) using the continuity equation (p<0.001). CONCLUSIONS: The tested transthoracic 3D-echocardiography technique offers non-invasive measurement of the LVOT and aortic valve area based on the continuity equation during systole and thus improves accuracy and, additionally, agreement of aortic valvular area determination with invasive and direct measurements.

Association of adiponectin with adverse outcome in coronary artery disease patients: results from the AtheroGene study.

AIMS: In primary prevention, the adipocytokine adiponectin seems to be protective against diabetes mellitus and cardiovascular disease. Data in patients with manifest coronary artery disease (CAD) are scant stimulating the investigation of the association of adiponectin concentrations and cardiovascular outcome in a prospective CAD cohort. METHODS AND RESULTS: In 1890 consecutive patients with documented CAD [1130 with stable angina (SAP) and 760 with acute coronary syndrome (ACS)] baseline concentrations of adiponectin were measured by enzyme-linked immuno assay. During a median follow-up of 2.5 years cardiovascular events were registered (cardiovascular deaths 70; non-fatal myocardial infarction 46). Baseline adiponectin concentrations were similar in patients presenting with SAP [9.03 microg/mL (6.7, 13.45)] or ACS [9.19 microg/mL (6.72, 13.15)], P = 0.779. Kaplan-Meier survival analysis showed a stepwise decrease in event-free survival across quartiles of adiponectin baseline concentration (P log rank = 0.0188). A similar pattern was observed in both subgroups of patients (SAP P = 0.075 and ACS P = 0.254). In univariate analyses, continuous adiponectin concentration was related to event-free survival in all patients [HR 1.02 (95% confidence interval 1.0-1.04), P = 0.012] as well as in the subgroup of SAP subjects [1.03 (1.01-1.05), P = 0.012]. The relation was less strong in the subgroup presenting with ACS [1.014 (0.99-1.04), P = 0.280]. A correlation of adiponectin with high density cholesterol (r = 0.39) and a negative relation to triglyceride levels (r = -0.22) could be described. An increase of one interquartile distance in adiponectin concentration was associated with a 1.17-fold risk for future cardiovascular events (P = 0.013), in B-type natriuretic peptide (BNP) it meant a 1.13-fold risk (P < 0.001). In the overall patient group, this risk association remained robust after the adjustment for classical risk factors, clinical presentation and cardiac medication. Only after adjustment for BNP adiponectin lost its independent predictive value. CONCLUSION: In contrast to studies including initially healthy individuals, the current prospective study demonstrates that adiponectin is associated with adverse cardiovascular outcome in patients with manifest CAD.

The value of N-terminal fragment of brain natriuretic peptide and tissue inhibitor of metalloproteinase-1 levels as predictors of cardiovascular outcome in the LIPID study.

AIMS: We sought to determine the association between two major biomarkers, the inactive N-terminal fragment of brain natriuretic peptide (NT-proBNP) and tissue inhibitor of metalloproteinase-1 (TIMP-1) and long-term cardiovascular outcomes in a cohort of subjects who had a myocardial infarction or unstable angina 3-36 months previously. METHODS AND RESULTS: Plasma NT-proBNP and TIMP-1 were measured in a nested case control study of 250 randomly matched subject pairs enrolled in the long-term intervention with pravastatin in ischaemic disease (LIPID) and LIPID extended follow-up studies. Cases (n = 250) were defined as those who had a cardiovascular death, non-fatal myocardial infarction or stroke during the studies. Controls (n = 250) remained event-free for the same follow-up duration (average 2.5 years) as the matched cases. The relationships between cases and plasma NT-proBNP and TIMP-1 were adjusted for the LIPID risk score, treatment allocation and other biomarkers (CRP, IL-6 and white cell count), and examined using a multivariable conditional logistic regression model. NT-proBNP levels were significantly higher in the cases than in the controls [389 (152-864) vs. 198 (93-416) pg/mL, median (25%-75% percentiles), P < 0.001]. The odds ratio (OR) of recurrent cardiovascular events in individuals in the highest quartile was three times higher than those in the lowest quartile (95% confidence interval (CI) 1.8-5.1; P < 0.001). Similarly, TIMP-1 levels were significantly higher among cases compared with controls (806 vs. 736 pg/mL, median: highest vs. lowest quartile: OR 2.8, 95% CI 1.6-4.7; P < 0.001). After adjustment for the LIPID risk score, treatment with pravastatin and other biomarkers, both NT-proBNP and TIMP-1 predicted cardiovascular events significantly and independently of each other. CONCLUSION: The study suggests that in subjects with stable ischaemic disease, NT-proBNP and TIMP-1 are independent predictive markers of coronary heart disease outcome.