High-sensitivity C-reactive protein is not a risk factor for venous thromboembolism: the Tromso study

C-reactive protein is a predictor for lower-extremity deep venous thrombosis in patients with primary intracerebral hemorrhage

OBJECTIVE

Our study aimed to determine whether there exists an association between low-grade systemic inflammation, as measured by serum C-reactive protein (CRP), and the risk of lower-extremity deep venous thrombosis (LEDVT) in patients with primary intracerebral hemorrhage (ICH).

METHODS

This observational study was retrospectively conducted on patients with primary ICH who were presented to two tertiary medical centers between January 2021 and August 2022. The primary outcome was detecting LEDVT occurrence within 14 days from the onset of the acute ICH episode. Weighted logistic regression and restricted cubic spline models were employed to estimate the association between CRP and LEDVT following 1:1 propensity score matching (PSM).

RESULTS

Of the 538 patients with primary ICH who met the inclusion criteria, 76 (14.13%) experienced LEDVT. Based on the cut-off levels of CRP measured upon admission from the receiver operating characteristic (ROC) curve, patients with primary ICH were categorized into two groups: (i) CRP < 1.59 mg/L and (ii) CRP ≥ 1.59 mg/L. After 1:1 PSM, the LEDVT events occurred in 24.6% of patients with CRP ≥ 1.59 mg/L and 4.1% of patients with CRP < 1.59 mg/L (P < 0.001). ROC curve revealed the area under the ROC curve of 0.717 [95% confidence interval (CI) 0.669-0.761, P < 0.001] for CRP to predict LEDVT with a sensitivity of 85.71% and specificity of 56.29%. After adjusting for all confounding variables, the occurrence of LEDVT in ICH patients with higher CRP levels (≥ 1.59 mg/L) was 10.8 times higher compared to those with lower CRP levels (95% CI 4.5-25.8, P < 0.001). A nonlinear association was observed between CRP and an increased risk of LEDVT in the fully adjusted model (P for overall < 0.001, P for nonlinear = 0.001). The subgroup results indicated a consistent positive link between CRP and LEDVT events following primary ICH.

CONCLUSIONS

Higher initial CRP levels (CRP as a dichotomized variable) in patients with primary ICH are significantly associated with an increased risk of LEDVT and may help identify high-risk patients with LEDVT. Clinicians should be vigilant to enable early and effective intervention in patients at high risk of LEDVT.

C-reactive protein, immunothrombosis and venous thromboembolism

C-reactive protein (CRP) is a member of the highly conserved pentraxin superfamily of proteins and is often used in clinical practice as a marker of infection and inflammation. There is now increasing evidence that CRP is not only a marker of inflammation, but also that destabilized isoforms of CRP possess pro-inflammatory and pro-thrombotic properties. CRP circulates as a functionally inert pentameric form (pCRP), which relaxes its conformation to pCRP* after binding to phosphocholine-enriched membranes and then dissociates to monomeric CRP (mCRP). with the latter two being destabilized isoforms possessing highly pro-inflammatory features. pCRP* and mCRP have significant biological effects in regulating many of the aspects central to pathogenesis of atherothrombosis and venous thromboembolism (VTE), by directly activating platelets and triggering the classical complement pathway. Importantly, it is now well appreciated that VTE is a consequence of thromboinflammation. Accordingly, acute VTE is known to be associated with classical inflammatory responses and elevations of CRP, and indeed VTE risk is elevated in conditions associated with inflammation, such as inflammatory bowel disease, COVID-19 and sepsis. Although the clinical data regarding the utility of CRP as a biomarker in predicting VTE remains modest, and in some cases conflicting, the clinical utility of CRP appears to be improved in subsets of the population such as in predicting VTE recurrence, in cancer-associated thrombosis and in those with COVID-19. Therefore, given the known biological function of CRP in amplifying inflammation and tissue damage, this raises the prospect that CRP may play a role in promoting VTE formation in the context of concurrent inflammation. However, further investigation is required to unravel whether CRP plays a direct role in the pathogenesis of VTE, the utility of which will be in developing novel prophylactic or therapeutic strategies to target thromboinflammation.

Plasma lipopolysaccharide-binding protein is a biomarker for future venous thromboembolism: Results from discovery and validation studies

BACKGROUND

Effect-size underestimation impedes biomarker identification. Long follow-up time in prospective studies attenuates effect-size estimates for transient biomarkers, while disease category-specific biomarkers are affected by merging of categories. Venous thromboembolism (VTE) encompasses deep vein thrombosis (DVT) and pulmonary embolism (PE).

OBJECTIVES

(i) To re-analyze untargeted proteomic data to identify biomarker candidates for future VTE that differ between DVT and PE and are attenuated by extended time between sampling and VTE. (ii) To perform targeted candidate validation.

PATIENTS/METHODS

A VTE case-control discovery study and a nested case-control validation study were derived from the general population surveyed in 1994-95. Plasma was obtained at study enrollment, and VTE events were registered until 2007. Untargeted proteomic data were re-analyzed for candidate discovery. Lipopolysaccharide-binding protein (LBP) was validated by enzyme-linked immunosorbent assay.

RESULTS

Elevated LBP was discovered as a candidate DVT biomarker in women with less than 3 years between blood sampling and DVT. In the validation study, the odds ratio (OR) for DVT was 2.03 (95% confidence intervals [CI]: 1.53-2.74) per standard deviation (SD) increase in LBP for women with less than 3 years between blood sampling and DVT. Adjustment for age, body mass index, and C-reactive protein attenuated the OR to 1.79 (95% CI: 1.25-2.62) per SD. In the validation study, we observed an OR for VTE of 0.47 (95% CI: 0.28-0.77) for men in the 25^th to 50^th percentiles when compared to the lowest quartile.

CONCLUSIONS

We discovered and validated increased LBP as a predictive biomarker for DVT in women. We found an increased VTE risk for men in the lowest quartile of LBP.

Hemostatic factors, inflammatory markers, and risk of incident venous thromboembolism: The Multi-Ethnic Study of Atherosclerosis

BACKGROUND

Several hemostatic factors and inflammatory markers are associated with the risk of incident venous thromboembolism (VTE), however, most existing data are from case-control studies in Caucasian populations.

OBJECTIVES

We aimed to prospectively confirm previous findings and explore less studied biomarkers in relation to VTE risk in a multi-racial/multi-ethnic cohort.

METHODS

Circulating levels of factor VIII, fibrinogen, D-dimer, plasmin-antiplasmin complex (PAP), C-reactive protein (CRP), and interleukin-6 (IL-6) were measured at baseline (2000-2002) in 6706 participants of the Multi-Ethnic Study of Atherosclerosis. Incident VTE was identified using hospitalization discharge codes from baseline to December 31, 2015. Hazard ratios (HRs) of VTE were estimated in Cox regression models.

RESULTS

There were 227 events during a median of 14 years of follow-up. Compared with participants in the lowest quartile, the HRs for those above the 95th percentile and p for trend across categories were 3.50 (95% confidence interval [CI] 1.98-6.19; p < .001) for D-dimer, 1.49 (95% CI 0.84-2.63; p = .02) for factor VIII, 1.32 (95% CI 0.76-2.28; p = .99) for fibrinogen, 1.92 (95% CI 1.08-3.42; p = .15) for PAP, 1.68 (95% CI 0.81-3.48; p = .08) for CRP, and 2.55 (95% CI 1.15-5.66; p = .07) for IL-6, after adjustment for demographics and body mass index. For CRP and IL-6, follow-up was restricted to 10 years because of violations of the proportional hazards assumption. No significant interactions by age/ethnicity were observed.

CONCLUSIONS

We demonstrated a fairly novel association between PAP and risk of incident VTE, and contributed further prospective confirmation regarding the associations of D-dimer, factor VIII, and IL-6 with VTE.

Inflammatory Biomarkers in the Short-Term Prognosis of Venous Thromboembolism: A Narrative Review

The relationship between inflammation and venous thrombosis is not well understood. An inflammatory response may be both the cause and consequence of venous thromboembolism (VTE). In fact, several risk factors of VTE modulate thrombosis through inflammatory markers. Acute pulmonary embolism (PE) is burdened by a remarkable mortality rate, up to 34% in severely ill patients presenting with hemodynamic instability. Initial mortality risk stratification is based on hemodynamic instability. Patients with a situation of hemodynamic stability require immediate further risk assessment based on clinical, imaging, and circulating biomarkers, as well as the presence of comorbidities. Some inflammatory biomarkers have shown potential usefulness in the risk stratification of patients with VTE, especially acute PE. C-reactive protein on admission is associated with 30-day mortality and bleeding in VTE patients. P-selectin is associated with right ventricle dysfunction in PE patients and might be associated with VTE recurrences and the extension of thrombosis. Tissue factor microparticles are associated with VTE recurrence in cancer-associated thrombosis. Other inflammatory biomarkers present scarce evidence (inflammatory cytokines, erythrocyte sedimentation rate, fibrinogen, leukocyte count). In this manuscript, we will review the prognostic role of different inflammatory biomarkers available both for clinical practice and research in VTE patients.

Can the Level of CRP in Acute Pulmonary Embolism Determine Early Mortality?

OBJECTIVE

The purpose of this study was to determine the prognostic role of C-Reactive Protein (CRP) in acute PE.

MATERIAL AND METHODS

Two hundred and twenty patients with acute PE were consecutively enrolled and followed for 30 days after discharge. Serum CRP and NT-proBNP were determined. Right ventricular function was evaluated by transthoracic echocardiography.

RESULTS

There was a significant difference in age, S-PESI, and CRP levels between the early mortality group and without early mortality group. There was statistically no significant difference between the groups with and without early mortality in terms of gender distribution and whether or not they received thrombolytic therapy for DVT. Pulmonary infarct, pleural fluid, or both have no effect on early mortality. There was no correlation between CRP and pro-BNP, right/left ventricular ratio. The serum CRP levels at diagnosis were significantly higher in patients with PE and with pleural effusion and pulmonary infarct than those in PE patients without pleural effusion and pulmonary infarct (4.75±4.91 ng/mL, 9.67±8.02 ng/mL; p<0.0003).

CONCLUSION

High levels of CRP owing to inflammation in pulmonary embolism associated with effusion and infarction reveals why early mortality is significant in this group. CRP may help in the risk stratification of patients with acute PE, especially those with effusion and pulmonary infarction. CRP is an inexpensive and easily applicable biochemical marker, which can be used to predict early mortality.

Predicting the Risk of Recurrent Venous Thromboembolism: Current Challenges and Future Opportunities

Acute venous thromboembolism (VTE) is a commonly diagnosed condition and requires treatment with anticoagulation to reduce the risk of embolisation as well as recurrent venous thrombotic events. In many cases, cessation of anticoagulation is associated with an unacceptably high risk of recurrent VTE, precipitating the use of indefinite anticoagulation. In contrast, however, continuing anticoagulation is associated with increased major bleeding events. As a consequence, it is essential to accurately predict the subgroup of patients who have the highest probability of experiencing recurrent VTE, so that treatment can be appropriately tailored to each individual. To this end, the development of clinical prediction models has aided in calculating the risk of recurrent thrombotic events; however, there are several limitations with regards to routine use for all patients with acute VTE. More recently, focus has shifted towards the utility of novel biomarkers in the understanding of disease pathogenesis as well as their application in predicting recurrent VTE. Below, we review the current strategies used to predict the development of recurrent VTE, with emphasis on the application of several promising novel biomarkers in this field.

The role of serum bilirubin levels in determining venous thromboembolism

OBJECTIVE

Venous thromboembolism (VTE) is a disease that includes both deep venous thrombosis (DVT) and pulmonary embolism (PE). Bilirubin is an endogenous anti-inflammatory marker associated with atherothrombosis. The purpose of our study was to investigate the association of serum bilirubin levels with the presence of VTE.

METHODS

A total of 103 patients with VTE (distal DVT, n = 34; proximal DVT, n = 30; PE, n = 39) and 50 control patients were cross-sectionally enrolled. Peripheral venous duplex ultrasound and computed tomography were used for the diagnosis of VTE. Fasting blood samples were drawn for biochemical analyses.

RESULTS

Baseline characteristics were not different between groups. The VTE group had lower bilirubin level (9.0 ± 2.6 μmol/L vs 7.3 ± 3 μmol/L; P = .001) and higher high-sensitivity C-reactive protein (hs-CRP) concentration (0.8 [0.3-2] mg/L vs 1.1 [0.2-3] mg/L; P = .008) and white blood cell count (7.4 ± 1.5 × 10⁹/L vs 8.2 ± 2.7 × 10⁹/L; P = .02) compared with control patients. In the analysis of variance, the levels of total direct bilirubin and hs-CRP were clearly different between the control group and VTE subgroups (distal and proximal DVT and PE). The receiver operating characteristic curve analysis showed a cutoff value of 8.9 μmol/L for total bilirubin (sensitivity, 74%; specificity, 55%) and an area under the curve of 0.659 (P < .001).

CONCLUSIONS

Bilirubin level, hs-CRP concentration, and white blood cell count were independently associated with VTE.

C-reactive protein and risk of venous thromboembolism: results from a population-based case-crossover study

Long-term, low-grade inflammation does not seem to be a risk factor for venous thromboembolism. The impact of acute inflammation, regardless of cause, on risk of venous thromboembolism is scarcely studied. We aimed to investigate the impact of acute inflammation, assessed by C-reactive protein, on short-term risk of venous thromboembolism. We conducted a case-crossover study of patients with venous thromboembolism (n=707) recruited from a general population. Information on triggers and C-reactive protein levels were retrieved from hospital records during the 90 days before the event (hazard period) and in four preceding 90-day control periods. Conditional logistic regression was used to obtain β coefficients for change in natural log (ln) transformed C-reactive protein from control to hazard periods and to determine corresponding odds ratios for venous thromboembolism. Median C-reactive protein was 107 mg/L in the hazard period, and ranged from 7 mg/L to 16 mg/L in the control periods. The level of C-reactive protein was 58% (95% CI 39-77%) higher in the hazard period than in the control periods. A one-unit increase in ln-C-reactive protein was associated with increased risk of venous thromboembolism (OR 1.79, 95% CI 1.48-2.16). The risk estimates were only slightly attenuated after adjustment for immobilization and infection. In stratified analyses, ln-C-reactive protein was associated with increased risk of venous thromboembolism in cases with (OR 1.55, 95% CI 1.01-2.38) and without infection (OR 1.77, 95% CI 1.22-2.57). In conclusion, we found that acute inflammation, assessed by C-reactive protein, was a trigger for venous thromboembolism.

The association between red cell distribution width and venous thromboembolism is not explained by myocardial infarction, stroke, or cancer

BACKGROUND

Red cell distribution width (RDW) is a risk marker of venous thromboembolism (VTE), myocardial infarction (MI), stroke, and cancer. Due to interrelations between these diseases, the association between RDW and VTE may be explained by MI, stroke, or cancer.

OBJECTIVE

To investigate whether the effect of RDW on VTE could be explained by intermediate development of MI, stroke, or cancer.

METHODS

RDW was measured in 24 363 participants of the Tromsø Study in 1994-1995. Incident VTE, MI, stroke, and cancer were registered until December 31, 2010. Conventional and cause-specific Cox-regression models were used to estimate hazard ratios (HR) for VTE with 95% confidence intervals (CI) across categories of RDW.

RESULTS

There were 502 first VTEs during a median follow-up of 16 years. In conventional Cox regression analysis, RDW in the highest quartile was associated with a 71% (HR 1.71, 95% CI 1.09-2.67) and 27% (HR 1.27, 95% CI 0.88-1.85) higher risk of VTE in men and women, respectively, compared to subjects in the lowest quartiles. The risk of VTE among subjects with RDW in the highest quartile was similar for men and women of postmenopausal age. In cause-specific analysis, where each individual contributed with person-time until the first occurring event only, the risk estimates were similar to those of the conventional Cox-regression analysis.

CONCLUSION

Our findings suggest that the association between RDW and future risk of VTE is not explained by intermediate development of MI, stroke, or cancer.

Impaired plasminogen binding in patients with venous thromboembolism: Association with protein carbonylation

INTRODUCTION

Venous thromboembolism (VTE) is associated with hypofibrinolysis. Its mechanisms are poorly understood. We investigated plasminogen-fibrin interaction and its association with fibrinolytic capacity and protein oxidation/carbonylation in VTE patients.

MATERIALS AND METHODS

Plasma-purified plasminogen conversion to plasmin and surface plasmon resonance employed for plasminogen-fibrin interactions were individually evaluated in all healthy controls and non-anticoagulated patients following VTE, 10-23months since the event. We also assessed plasma fibrin clot permeability (K_s), clot lysis time (LT), activators and inhibitors of fibrinolysis together with oxidation/carbonylation markers.

RESULTS

VTE patients had impaired plasminogen binding to fibrin (apparent Kd, +290%, p=0.002), reduced rate of plasmin generation (-4.7%, p=0.001), and longer LT (+18.6%, p<0.001) compared with controls. Fibrinogen and K_s were similar in both groups. Apparent Kd correlated with LT (r=0.43, p=0.037), tissue plasminogen activator-plasminogen activator inhibitor 1 (tPA-PAI-1) complexes (r=0.63, p=0.012), and active PAI-1 (r=0.49, p=0.03). Compared with controls, VTE patients had higher thiobarbituric acid reactive substances (TBARS), total protein carbonyl content (PC), and lower total antioxidant capacity (all p<0.001), that all were associated with LT (r=0.61, r=0.56, and r=-0.47, respectively, all p<0.05). Impaired plasminogen binding to fibrin reflected by apparent Kd positively correlated with TBARS (r=0.48, p=0.032) and PC (r=0.54, p=0.013) in the whole group.

CONCLUSIONS

Plasminogen-fibrin interactions are altered in young and middle-aged VTE patients, without known thrombophilias, except increased factor VIII. The mechanisms underlying these phenomena remain to be established.

Red cell distribution width is associated with incident venous thromboembolism (VTE) and case-fatality after VTE in a general population

Recent studies suggest an association between red cell distribution width (RDW) and incident venous thromboembolism (VTE). We aimed to investigate the impact of RDW on risk of incident and recurrent VTE, and case-fatality, in a general population. RDW was measured in 26,223 participants enrolled in the Tromsø Study in 1994–1995. Incident and recurrent VTE events and deaths during follow-up were registered until January 1, 2012. Multivariate Cox proportional hazards regression models were used to calculate hazard ratios (HR) with 95% confidence intervals (CI). There were 647 incident VTE events during a median of 16.8 years of follow-up. Individuals with RDW in the highest quartile (RDW≥13.3%) had 50% higher risk of an incident VTE than those in the lowest quartile (RDW≤12.3%). The association was strongest for unprovoked deep-vein thrombosis (HR highest vs lowest quartile of RDW: 1.8, 95% CI 1.1–3.1). VTE patients with baseline RDW≥13.3% had 30% higher risk of all-cause mortality after the initial VTE event than VTE patients with RDW<13.3%. There were no association between RDW and risk of recurrent VTE. Our findings suggest that high RDW is a risk factor of incident VTE, and that RDW is a predictor of all-cause mortality in VTE patients.

Heart healthy diet and risk of myocardial infarction and venous thromboembolism

Prudent dietary patterns are associated with reduced risk of arterial cardiovascular diseases (CVD). Limited data exist on the relation between diet and venous thromboembolism (VTE). The aim of our prospective, population based study was to investigate the association of a heart healthy diet on risk of myocardial infarction (MI) and VTE. Information on dietary habits was available in 18,062 subjects, aged 25–69, who participated in the fourth Tromsø study, 1994–1995. Dietary patterns were assessed by a slightly modified version of the validated SmartDiet score; a 13-item questionnaire producing a diet score based on the intakes of fat, fibre, fruit and vegetables. Incident events of MI (n=518) and VTE (n=172) were recorded to the end of follow-up December 31, 2005 (median follow-up 10.8 years). Cox-regression models were used to calculate hazard ratios (HR). A healthy diet score of >27 points (upper tertile) was associated with 17% reduced risk of MI (HR: 0.83, 95% confidence interval [CI]: 0.66–1.06), and no association with VTE (HR: 1.01; 95%CI: 0.66–1.56), compared to <24 points (lower tertile) in multivariable analysis. High intake of fish, fruit, vegetables and polyunsatured fat had a 23% reduced risk of MI (HR 0.77; 95%CI: 0.60–0.98), but no association with VTE (HR 0.95; 95%CI: 0.64–1.40). A heart healthy diet showed an even more favourable association with MI in obese subjects (HR: 0.62; 95%CI: 0.41–0.95), but not with VTE. Our findings suggest that a heart healthy dietary pattern is associated with moderately reduced risk of MI, but not related to risk of VTE.

Serum C-reactive protein increases the risk of venous thromboembolism: a prospective study and meta-analysis of published prospective evidence

Evolving debate suggests that C-reactive protein (CRP) might be associated with the development of venous thromboembolism (VTE); however, the evidence is conflicting. We aimed to assess the prospective association of CRP with VTE risk. C-reactive protein was measured in serum samples at baseline from 2420 men aged 42–61 years, from the Kuopio Ischemic Heart Disease study. Within-person variability in CRP levels was corrected for using repeat measurements of CRP taken 11 years after baseline. Incident VTE events (n = 119) were recorded during a median follow-up of 24.7 years. The age-adjusted regression dilution ratio for log_e CRP was 0.57 [95% confidence interval (CIs): 0.51–0.64]. In age-adjusted Cox regression analysis, the hazard ratio (95% CIs) for VTE per 1 standard deviation (SD) increase in log_e baseline CRP was 1.17 (0.98–1.40). Further adjustment for several established and emerging risk factors did not alter the association. In a meta-analysis of nine population-based studies (including the current study) comprising 81,625 participants and 2225 VTE cases, the fully-adjusted risk estimate for VTE was 1.14 (1.08–1.19) per SD increase in log_e baseline CRP. In a pooled dose–response analysis, a linear association between CRP and VTE risk was suggested (P for nonlinearity = 0.272). The pooled risk estimate for VTE per 5 mg/l increment in CRP levels was 1.23 (1.09–1.38). C-reactive protein was only modestly associated with VTE risk in the primary analysis. Pooled evidence, however, suggests that elevated CRP is associated with greater VTE risk, consistent with a linear dose–response relationship.

C-reactive protein, obesity, and the risk of arterial and venous thrombosis

Essentials We performed repeated measurements of C-reactive protein (CRP) and obesity in a cohort study. CRP was associated with risk of myocardial infarction and venous thromboembolism. CRP was a mediator for risk of myocardial infarction in obese men and women. CRP was a partial mediator for risk of venous thromboembolism in obese women, but not in men.

SUMMARY

Background Low-grade inflammation in obesity may be a shared pathway for the risk of venous thromboembolism (VTE) and myocardial infarction (MI). Objectives To investigate the associations between repeated measurements of C-reactive protein (CRP) and the risks of MI and VTE, and to explore whether CRP mediated these risks in obese subjects. Methods CRP and obesity measures were collected from 15 134 subjects who participated in one or more surveys of the Tromsø study in 1994-1995, 2001-2002, or 2007-2008. Incident VTEs and MIs were registered until 1 January 2011. Time-varying Cox regression models were used to calculate hazard ratios of MI and VTE according to categories of CRP and obesity measures. Results There were 291 VTEs and 920 MIs during follow-up. High levels of CRP (≥ 3 mg L(-1) versus < 1 mg L(-1) ) were associated with increased risks of MI (hazard ratio [HR] 1.73; 95% confidence interval [CI] 1.32-2.26) and VTE (HR 1.84; 95% CI 1.22-2.78) in women, but only with MI in men (HR 1.93; 95% CI 1.53-2.44). All obesity measures showed stronger associations with CRP in women than in men. In obese women (body mass index [BMI] of ≥ 30 kg m(-2) versus < 25 kg m(-2) ), adjustment for CRP attenuated the risk estimate for VTE by 22%, whereas the incidence rates of VTE increased with combined categories of higher BMI and CRP. No association was found in men. Conclusions Our findings suggest that low-grade inflammation, assessed by measurement of CRP, is associated with the risks of MI and VTE, and may be a shared pathway for MI and VTE in obesity.

Comparing effects of different routes of heparin administration on the serum biomarkers of thrombosis

BACKGROUND

Association between thrombosis pathogenesis and inflammatory conditions has been reported. Also inflammatory biomarkers have been proposed for prediction of thrombosis events.

OBJECTIVES

Effects of different methods of heparin administration (subcutaneous vs continuous infusion) as thromboprophylaxis on the biomarkers of thrombosis have been evaluated.

METHODS

Serum levels of hsCRP, IL-10 and P-selectin as the biomarkers of thrombosis were measured at baseline, days 3 and 7 during the patients' hospitalization period.

RESULTS

Changes in the serum levels of thrombosis biomarkers (hsCRP, IL-10 and P-selectin) were comparable between the subcutaneous and continuous infusion groups.

CONCLUSION

Both subcutaneous injection and continuous infusion of heparin as thromboprophylaxis showed same effects on the thrombosis biomarkers.

Red cell distribution width and carotid atherosclerosis progression. The Tromsø Study

Red cell distribution width (RDW), a measure of the size variability of circulating erythrocytes, is associated with cardiovascular morbidity and mortality. We aimed to investigate whether RDW was associated with progression of atherosclerotic plaques in subjects recruited from the general population. Baseline characteristics, including RDW, were collected from 4677 participants in the fourth survey of the Tromsø Study conducted in 1994/95. Prevalence of carotid plaques and total plaque area (TPA) were assessed by ultrasonographic imaging at baseline and after seven years of follow-up. Generalised linear models were used to analyse change in TPA across tertiles of RDW. Change in TPA was significantly higher across tertiles of RDW in crude analysis and in multivariable analysis adjusted for cardiovascular risk factors. The mean change in TPA increased from 5.6 mm² (4.9-6.4) in tertile 1 (RDW ≤ 12.6 %) to 6.7 mm² (5.9-7.6) in tertile 3 (RDW ≥ 13.3) in multivariable analysis adjusted for body mass index, total cholesterol, HDL cholesterol, systolic blood pressure, self-reported diabetes, smoking status, platelet count, white blood cell count, and hs-CRP levels (p for trend 0.003). A 1 % increase in RDW was associated with 0.6 mm² (0.1-1.2) increase in TPA in multivariable analysis (p=0.03). RDW was associated with progression of atherosclerosis after adjustments for traditional atherosclerotic risk factors. Our findings suggest that the link between RDW and cardiovascular morbidity and mortality may be explained by atherosclerosis.

Inflammation markers and incident venous thromboembolism: the REasons for Geographic And Racial Differences in Stroke (REGARDS) cohort

BACKGROUND

Inflammation biomarkers are associated with the venous thromboembolism (VTE) risk factors obesity and age; however, the relationships of inflammation with VTE risk remain controversial.

OBJECTIVES

To examine associations of four inflammation biomarkers, i.e. C-reactive protein (CRP), serum albumin, white blood cell (WBC) count, and platelet count (PLTC), with incident VTE, and to determine whether they mediate the association of age or obesity with VTE.

PATIENTS/METHODS

Hazards models adjusted for VTE risk factors were used to calculate the prospective association of each biomarker with incident VTE in 30,239 participants of the REasons for Geographic And Racial Differences in Stroke (REGARDS) study. Mediation of the associations of obesity and age with VTE were examined by bootstrapping. Over a period of 4.6 years, there were 268 incident VTE events. After adjustment for VTE risk factors, the hazard ratios (HRs) were 1.25 (95% confidence interval [CI] 1.09-1.43) per standard deviation (SD) higher log-CRP and 1.25 (95% CI 1.06-1.48) per SD lower albumin; there were no associations for WBC count or PLTC. The association of body mass index (BMI), but not age, with VTE was partially mediated by CRP and albumin. In risk factor-adjusted models, the percentage attenuations of the BMI HR for VTE after introduction of CRP or albumin into the models were 15.4% (95% CI 7.7-33.3%) and 41.0% (95% CI 12.8-79.5%), respectively.

CONCLUSION

Higher CRP levels and lower serum albumin levels were associated with increased VTE risk, and statistically mediated part of the association of BMI with VTE. These data suggest that inflammation may be a potential mechanism underlying the relationship between obesity and VTE risk.

The Role of the Nonspecific Inflammatory Markers in Determining the Anatomic Extent of Venous Thromboembolism

We aimed to investigate the relationship between the extent of venous thromboembolism (VTE) and nonspecific inflammatory markers such as neutrophil to lymphocyte ratio (NLR) and high-sensitivity C-reactive protein (hs-CRP). We retrospectively enrolled 77 patients with VTE (distal deep vein thrombosis [DVT], n = 19; proximal DVT, n = 32; and pulmonary thromboembolism [PTE], n = 26) and 34 healthy controls. In the performed analysis of variance, the levels of white blood cell, NLR, and hs-CRP were clearly different among the groups (control, distal and proximal DVT, and PTE) ( P < .001). Especially, a significant increase from the control group to the DVT and PTE was observed in the analysis made for NLR. In the performed receiver–operating characteristic curve analysis, area under curve (AUC) = 0.849 and P < .001 were detected for NLR > 1.84. For this value, the sensitivity and specificity were determined as 88.2% and 67.6%, respectively. The NLR is an inexpensive and a readily available marker that may be effective in determining the extent of VTE, and it is useful for risk stratification in patients with VTE.

Atorvastatin favorably modulates proinflammatory cytokine profile in patients following deep vein thrombosis

BACKGROUND

Venous thromboembolism (VTE) has been shown to be associated with inflammation. Statins that might reduce VTE risk have been found to exert anti-inflammatory properties in patients at cardiovascular risk. We sought to investigate whether anti-inflammatory effects of atorvastatin can be observed in VTE patients.

MATERIALS AND METHODS

Atorvastatin 40 mg/d was given for 3 days to 26 consecutive VTE patients following discontinuation of anticoagulant therapy and 25 controls. We evaluated interleukin (IL)-1b, IL-6, IL-8, IL-10, soluble P-selectin and von Willebrand factor (vWF) antigen in peripheral venous blood.

RESULTS

The VTE patients displayed higher C-reactive protein (p=0.013), IL-1b (p=0.03), IL-8 (p=0.03) and vWF (p<0.0001) compared with the controls. In VTE patients atorvastatin decreased IL-6 (p=0.0003), IL-8 (p=0.003) and P-selectin (p<0.0001), but increased IL-10 (p=0.001), with no association with C-reactive protein or cholesterol-lowering effects. Atorvastatin reduced IL-1b (p=0.01), IL-6 (p=0.03) and P-selectin (p=0.002) in controls. Residual venous thrombosis was associated with elevated IL-6 and P-selectin, whereas patients with proximal deep vein thrombosis showed elevated P-selecitn prior to and following statin administration (all p<0.05).

CONCLUSION

A 3-day administration of atorvastatin reduces inflammation without decrease in C-reactive protein in VTE patients.

Abdominal obesity and the risk of venous thromboembolism among women: a potential role of interleukin-6

BACKGROUND

Abdominal obesity increases the risk of venous thromboembolism (VTE). It remains unclear to what extent inflammation contributes to the risk of VTE from abdominal obesity. Our objectives were to investigate the association between abdominal obesity and VTE and the effect of inflammation on this association in a case-control study comprised of women.

METHODS

We included 84 patients with VTE (18-60 years of age) and 100 controls. Waist circumference (WC), interleukin-6 (IL-6), and high-sensitivity C-reactive protein (hsCRP) levels were determined at least 7 months after the thrombotic event.

RESULTS

A total of 51 patients (61%) and 43 (43%) controls had abdominal obesity (WC ≥88 cm). The odds ratios (OR) adjusted for age were 2.40 [95% confidence interval (CI) 1.06-5.41; P=0.035] for a WC ≥88 cm compared to a WC <80 cm; the association was attenuated after adjusting for IL-6 (OR 1.86, 95% CI 0.80-4.33; P=0.149). For every 10-cm increment in WC, the risk of VTE adjusted for age increased by 1.38 (95% CI 1.08-1.77; P=0.010). The effect of an increased WC on the risk of VTE was again attenuated when IL-6 was entered in the regression model (OR 1.24, 95% CI 0.95-1.61; P=0.109). Risk estimates did not substantially change with adjustment for hsCRP.

CONCLUSION

Our data indicate that the association between VTE and an increased WC was attenuated after adjustment for IL-6, suggesting a potential role of this interleukin in mediating the link between abdominal obesity and VTE.