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Accumulating evidence indicates that microparticles (MPs) are important mediators of the interaction between cancer and the hemostatic system. We conducted a large prospective cohort study to determine whether the number of circulating procoagulant MPs is elevated in cancer patients and whether the elevated MP levels are predictive of occurrence of venous thrombembolism (VTE). We analyzed plasma samples of 728 cancer patients from the ongoing prospective observational Vienna Cancer and Thrombosis Study. Study endpoint was the occurrence of symptomatic VTE. Sixty-five age- and sex-matched healthy controls were recruited for defining the cut-off point for elevated MPs (4.62 nanomolar phosphatidylserine [nM PS]), which was set at the 95th percentile of MP levels in healthy controls. The measurement of MPs was performed after capture onto immobilized annexin V, and determination of their procoagulant activity was quantified with a prothrombinase assay. During a median observation period of 710 days, 53 patients developed VTE. MP levels (nM PS) were significantly higher in cancer patients than in healthy controls (median [25th-75th percentile], 3.95 [1.74-7.96] vs. 1.19 [0.81-1.67], p<0.001). Multivariate analysis including age, sex, surgery, chemo- and radiotherapy showed no statistically significant association of the hazard ratio of elevated MPs with VTE (0.95 [95% CI, 0.55-1.64], p=0.856). In conclusion, MP levels were elevated in cancer patients compared to healthy individuals in this study. However, elevated MP levels were not predictive of VTE.

The risk of venous thromboembolism (VTE) is increased in cancer patients. To improve prediction of VTE in cancer patients, we performed a prospective and observational cohort study of patients with newly diagnosed cancer or progression of disease after remission. A previously developed risk scoring model for prediction of VTE that included clinical (tumor entity and body mass index) and laboratory (hemoglobin level and thrombocyte and leukocyte count) parameters was expanded by incorporating 2 biomarkers, soluble P-selectin, and D-Dimer. Of 819 patients 61 (7.4%) experienced VTE during a median follow-up of 656 days. The cumulative VTE probability in the original risk model after 6 months was 17.7% in patients with the highest risk score (≥ 3, n = 93), 9.6% in those with score 2 (n = 221), 3.8% in those with score 1 (n = 229), and 1.5% in those with score 0 (n = 276). In the expanded risk model, the cumulative VTE probability after 6 months in patients with the highest score (≥ 5, n = 30) was 35.0% and 10.3% in those with an intermediate score (score 3, n = 130) as opposed to only 1.0% in patients with score 0 (n = 200); the hazard ratio of patients with the highest compared with those with the lowest score was 25.9 (8.0-84.6). Clinical and standard laboratory parameters with addition of biomarkers enable prediction of VTE and allow identification of cancer patients at high or low risk of VTE.

Cancer patients are at high risk for venous thromboembolism (VTE). Laboratory parameters with a predictive value for VTE could help stratify patients into high- or low-risk groups. The cell adhesion molecule P-selectin was recently identified as risk factor for VTE. To investigate soluble P-selectin (sP-selectin) in cancer patients as risk predictor for VTE, we performed a prospective cohort study of 687 cancer patients and followed them for a median (IQR) of 415 (221-722) days. Main tumor entities were malignancies of the breast (n = 125), lung (n = 86), gastrointestinal tract (n = 130), pancreas (n = 42), kidney (n = 19), prostate (n = 72), and brain (n = 80); 91 had hematologic malignancies; 42 had other tumors. VTE occurred in 44 (6.4%) patients. In multivariable analysis, elevated sP-selectin (cutoff level, 53.1 ng/mL, 75th percentile of study population) was a statistically significant risk factor for VTE after adjustment for age, sex, surgery, chemotherapy, and radiotherapy (hazard ratio = 2.6, 95% confidence interval, 1.4-4.9, P = .003). The cumulative probability of VTE after 6 months was 11.9% in patients with sP-selectin above and 3.7% in those below the 75th percentile (P = .002). High sP-selectin plasma levels independently predict VTE in cancer patients. Measurement of sP-selectin at diagnosis of cancer could help identify patients at increased risk for VTE.

Introduction: Protein Z serves as cofactor for the inactivation of factor Xa by the plasma protein Z-dependent protease inhibitor. Deficiency of protein Z was reported to exhibit a clinical manifestation like lupus anticoagulant characterised by thrombosis and fetal loss. As anti-protein Z antibodies may be associated with low protein Z levels, we hypothesised that anti-protein Z antibodies might play a role in lupus anticoagulant (LA)., Materials and Methods: Anti-protein Z antibodies were measured by commercially available ELISA in 102 LA-patients (69 with and 33 without thrombosis) and 33 healthy volunteers., Results: Elevated anti-protein Z IgG and/or IgM, IgG and IgM antibody levels were more prevalent among LA-patients (62%, 35%, 45%) than among controls (50%, 25%, 25%), but the difference was only statistically significant for the IgM subtype (p=0.037). Anti-protein Z IgG (odds ratio [OR] 0.77, 95% confidence interval [CI] 0.33-1.82) and IgM (OR 0.82, CI 0.35-1.88) antibody levels in the highest quartile of controls did not indicate an increased risk for thrombosis among LA-patients. Anti-protein Z IgG (OR 2.0, CI 0.5-7.6) and IgM (OR 1.8, CI 0.5-6.6) antibody levels in the highest quartile of controls were more prevalent in women with pregnancy loss than in those with normal pregnancy, but the difference was not statistically significant., Conclusion: Our data indicate that anti-protein Z antibodies are not associated with thrombosis in LA. However, women with LA and pregnancy loss show a tendency towards elevated anti-protein Z antibody levels.

Lupus anticoagulants (LA) are a surrogate marker for the risk of thromboembolic disease (TE). However, not all individuals with LA acquire TE, and it is desirable to distinguish those at risk for TE from those without. Platelets polymorphisms may contribute to the risk of TE, mainly those of glycoprotein (GP)Ibalpha: these are the variable number of tandem repeats (VNTR) and a dimorphism in the Kozak region, which affect platelet plug formation in healthy individuals under high shear stress rates. We determined polymorphisms within the GPIbalpha in individuals with persistent LA and a history of TE (LA/TE+) and in those without TE (LA/TE-). Further, we measured platelet function, as estimated by the collagen-epinephrine closure time (CEPI-CT) of the platelet function analyzer PFA-100 and compared all data with healthy controls. There was no difference of the VNTR alleles compared to healthy controls. The (-5)C allele of the Kozak dimorphism was significantly more frequent in LA patients compared to controls (p = 0.04), as a result of its increased frequency in LA/TE+ (vs controls p = 0.04), but there was no difference between LA/TE+ and LA/TE-. The increased frequency of the (-5)C allele resulted in an overrepresentation of (-5)TC genotype in the LA/TE+ group (p = 0.02) but not in a subgroup of 18 patients with arterial disease. The CEPI-CT of the PFA-100 was shorter in LA/TE+ than in LA/TE- (p = 0.044), but this difference did not persist after exclusion of patients with low platelet counts or low ristocetin cofactor activity. Unlike in healthy individuals, the CEPI-CT was not related to any Kozak dimorphism, neither in LA/TE-, nor in LA/TE+. Thus, the Kozak dimorphism may just contribute to stronger factors disposing individuals with LA towards TE without any discernible effect on their in vitro platelet function estimated by the PFA-100.

The angiotensin-converting enzyme (ACE) has been suggested to affect blood coagulation and fibrinolysis. Results from literature on the role of the frequent insertion/deletion (I/D) polymorphism in the ACE gene in venous thromboembolism (VTE) are controversial. Only limited data on ACE serum levels inVTE exist. We determined the ACE I/D polymorphism by genotyping and ACE serum levels by an enzymatic assay in 100 high-risk patients with objectively confirmed recurrentVTE and at least one event of an unprovoked deep venous thrombosis or pulmonary embolism. One hundred twenty-five age- and sex-matched healthy individuals served as controls. ACE genotype frequencies were not significantly different between patients (DD: 26.0%, ID: 52.0%, II: 22.0%) and controls (DD: 29.6%, ID: 44.8%, II: 25.6%; p = 0.56). Neither individuals with ACE DD genotype nor those with ACE ID genotype had a higher risk for VTE in comparison to those with ACE II genotype (odds ratio and [95% confidence interval]: 1.0 [0.5-2.1] and 1.4 [0.7-2.6], respectively). Serum ACE levels (U/l) did not differ between patients (median = 25.25, 25th -75th percentile: 20.20-33.70) and controls (24.20, 17.85-34.50, p = 0.49). In the total population involved in the study the ACE DD genotype (n = 63: 36.00 [26.40-43.00]) was associated with higher ACE levels than the ACE ID genotype (n = 108: 24.10 [19.80-31.48], p < 0.001) and the ACE II genotype (n = 54: 19.35 [15.00-22.95], p < 0.001). In conclusion, we found a significant association of the ACE I/D polymorphism with ACE serum levels. However, neither the serum levels nor the I/D genotype were associated with VTE.

Objective: There are only few studies on agonist-inducible platelet activation in chronic idiopathic autoimmune thrombocytopenia (cAITP)., Materials and Methods: We compared agonist (TRAP-6, ADP, Arachidonic acid, Epinephrine, and Ristocetin) -inducible P-selectin expression and PAC-1 binding in 40 patients with cAITP (f/m ratio 23/17) with those in 20 healthy controls. Results were correlated with platelet counts, detectable platelet antibodies, and reticulated platelets., Results: The in vivo activation of platelets determined the in vitro inducible response to agonists. The stronger the in vivo activation the less the number of platelets responding to agonists, as illustrated by the inverse correlation of P-selectin expression ex vivo and the relative increase after the exogenous addition of agonists. The agonist-inducible platelet activation was not associated with the presence of detectable platelet antibodies to GPIb/IX or GPIIb/IIIa. Agonist-inducible platelet activation was also not correlated with counts of reticulated platelets., Conclusion: Agonist-inducible activation of platelets in cAITP is affected mainly by their in vivo activation.

Patients with malignancy, particularly patients with high-grade glioma (HGG; WHO grade III/IV), have an increased risk of venous thromboembolism (VTE). It has been suggested that VTE predicts survival in cancer patients. The aim of our study was to investigate the occurrence of symptomatic VTE and its impact on survival in patients with HGG. Consecutive patients (n = 63; 36 female, 27 male; median age, 58 years) who had neurosurgical intervention between October 2003 and December 2004 were followed after surgery until October 2005. Objectively confirmed VTE was recorded as an event. All patients had received thrombosis prophylaxis with low-molecular-weight heparin (LMWH) during the immediate postoperative period. Subsequently, 56 patients received radiochemotherapy, 6 radiotherapy, and 1 chemotherapy only. Patients were followed over a median time period of 348 days. Fifteen patients (24%) developed VTE. Pulmonary embolism was diagnosed in nine patients (60%) and was fatal twice. The cumulative probability of VTE was 21% after three months and 26% after 12 months. The highest frequency of VTE was observed in patients with biopsy and subtotal tumor resection (n = 37; multivariate hazard ratio, 3.58; 95% CI = 0.98-13.13; P = 0.054) compared with patients with total resection. Survival did not significantly differ among patients with and without VTE and was 53% after 12 months in both groups. Patients with HGG, particularly those with biopsy and subtotal resection, are at high risk to develop VTE postoperatively. Thrombosis was not associated with a significant reduction of survival.

Individuals with lupus anticoagulants (LA) are at risk for thromboembolism (TE). Chronic inflammation is an important characteristic in LA patients which may dispose for TE. Platelets play a key role in inflammation and TE. We therefore investigated gene polymorphisms as well as plasma levels of platelet receptors as predictors of TE in 107 LA patients. We compared 74 patients with a history of thromboembolic disease (TE+), 56 with venous thrombosis (VT), 12 with arterial thrombosis (AT), and six patients who had both, with 33 LA patients without previous thrombosis (TE-). The P-selectin Pro715 allele was slightly more frequent in VT (OR = 3.167,95% CI 0.955-10.503; p = 0.0594), but no patient with AT had this allele (OR = 0.099, 95 % CI 0.001-0.790; p = 0.0238) which therefore may protect from AT. Plasma levels of P-selectin, collected a median of 35 months (range 2-329 months) after the last thrombotic event, were higher in patients withVT (p = 0.0096) than in TE-, but not with AT (p = 0.4713). These high P-selectin levels were not explained by the P-selectin polymorphism. The CA repeat polymorphism in the 3'-noncoding region of CD154 was significantly associated with the development of AT (OR = 4.035,95 % CI 1.329-12.249; p = 0.0138). Plasma levels of CD154 were not significantly different among the subgroups. Thus, the Thr715Pro polymorphism of P-selectin and CA repeats of CD154 are differentiating between the risk for VT and AT. Further, soluble P-selectin is elevated in LA patients with previous VT, but its role to predict VT needs to be evaluated in prospective studies.

Introduction: Elevated lipoprotein (a) (Lp (a)) has been established as a risk factor of coronary heart disease and stroke. Findings concerning the risk of venous thromboembolism (VTE) in adults are contradictory. The aim of our study was to investigate, whether elevated Lp (a) levels are an independent risk factor of spontaneous symptomatic venous thromboembolism (VTE). Our study was further designed to detect differences in risk profiles between thrombosis patients with and without symptomatic PE., Materials and Methods: We investigated Lp (a) in 128 patients with spontaneous symptomatic deep vein thrombosis (DVT, group 1), 105 with spontaneous symptomatic pulmonary embolism with or without DVT (PE, group 2) and 122 healthy controls. Lp (a) was measured with an immunoturbidimetric assay (Tina-quant(R), Roche, Grenzach-Wyhlen, Germany) on a Hitachi-Modular system., Results: Lp (a) levels (mg/L) were not significantly different among groups, median levels (25th-75th percentiles) were 170 (51-386) in group 1, 140 (<20-427) in group 2 and 126 (54-331) in controls, respectively. As continuous variable, odds ratios for VTE for a 100 mg/L increase of Lp (a) were 1.1 [95% confidence interval 0.98-1.2] for group 1 versus controls and 1.1 [0.95-1.2] for group 2 versus controls. The prevalence of Lp (a) above 300 mg/L was not significantly different among patients and controls (group 1: 30%, group 2: 32% and controls: 25%, p=0.4, p=0.2, respectively)., Conclusions: In conclusion we found no association between Lp (a) and VTE regardless whether DVT occurred together with PE or not.

Introduction: Thromboembolism is a common manifestation of lupus anticoagulant (LA), however only a subgroup of LA-patients is affected by thrombosis. Study objective was to investigate whether anti-prothrombin antibodies can identify LA-patients at increased risk for thrombosis., Materials and Methods: In total 79 patients, 50 with (42 men/8 women) and 29 without thrombosis (21 men/8 women), were investigated for their presence of anti-prothrombin IgG and IgM antibodies using assays from two different manufacturers (Aeskulisa=assay I, CoaChrom=assay II)., Results: The prevalence of elevated levels of anti-prothrombin IgG, IgM as well as IgG and/or IgM antibodies was 66% [assayI] (36% [assayII]), 38% (24%) and 72% (50%) in patients with thrombosis and 55% (24%), 28% (28%) and 66% (41%) in patients without thrombosis, respectively. Neither anti-prothrombin IgG or IgM nor IgG and/or IgM antibodies were found to indicate an increased risk for thrombosis. In the subgroup of patients with arterial or venous thrombosis there was also no association between anti-prothrombin antibodies and thrombosis. The comparison of median levels of IgG and IgM anti-prothrombin antibodies between patients with and without thrombosis yielded a borderline statistically significant difference only for anti-prothrombin IgG antibodies by using assay II (p=0.033), all other comparisons were not statistically significant., Conclusions: In conclusion, presence of anti-prothrombin antibodies was not associated with thromboembolism in LA-patients.

Platelets from 42 patients (platelet counts median 42x10(9)/L, range 3-223x10(9)/L) with chronic idiopathic autoimmune thrombocytopenia (cAITP) were investigated for P-Selectin expression and PAC-1 binding. The results showed that the levels of P-Selectin positive platelets (n=20) were higher in cAITP than in controls (P<0.0001), and correlated with platelet counts (P=0.04). PAC-1 binding was increased in only six patients, and not correlated with platelet counts. There was no correlation of P-Selectin or PAC-1 with detectable platelet antibodies. Thus, platelets are activated in cAITP, but platelets, characterized by PAC-1 binding, are rare. These are either needed to maintain vascular integrity, or underwent premature sequestration., (Copyright (c) 2006 Wiley-Liss, Inc.)

Limited data are available regarding complications of pregnancy and pregnancy outcome under prophylaxis with low-molecular-weight heparin (LMWH) in women with a history of thromboembolism (TE). We retrospectively evaluated pregnancy complications in a cohort of 80 women. All had a history of TE (76 venous, two arterial and two venous and arterial) and received prophylactic LMWH during 86 pregnancies. The rate of preeclampsia and stillbirth in these women was compared to that of a control group of 313 women without a history of TE and LMWH. Prophylaxis was started at a median of 10 weeks of gestation and usually continued until six weeks post partum. In 94% of the cases the outcome of pregnancy was favourable with a live birth. Four pregnancies (4.7%) ended in miscarriage. Two (2.3%) pregnancies were complicated by a thromboembolic event (one deep leg vein thrombosis and PRIND, respectively). One patient developed HELLP-syndrome. Severe preeclampsia occurred in three (3.8%) and stillbirth in one (1.3%) of the patients (n = 80), whereas this was the case in four (1.3%, odds ratio 3.01; 95% confidence interval (CI) 0.66-13.73, p = 0.15) and 10 (3.2%, OR = 0.38; 95% CI 0.05-3.04, p = 0.72) control women. Mean birth weight and standard deviation of infants was 3,160 +/- 930 g in patients and 3,300 +/- 540 g in controls (p = 0.11). We conclude that a favourable pregnancy outcome in women with a history of thromboembolism who use prophylactic LMWH during pregnancy can be expected. There was a trend towards a higher risk of preeclampsia, and these women should be carefully monitored for this complication.

Background: Anti-cardiolipin antibodies have been associated with both arterial and venous thrombosis, but their overall impact on all-cause or vascular mortality is unknown. In this study, we evaluated the influence of anti-cardiolipin antibodies on all-cause and vascular mortality., Methods: All individuals who fulfilled the inclusion criteria (completeness of data, no admission from an intensive care unit, unique identification with name and date of birth) and whose anti-cardiolipin antibodies were measured between October 2002 and February 2004 were included in this study (n = 4756; 64% female; median age, 46 years). Death/survival and cause of death were obtained from the Austrian Death Registry. The median observation period was 1.5 years, and the study comprised 7189 person-years., Results: During the study period, 184 patients (3.9%) died. There were no associations between either anti-cardiolipin IgM or IgG antibodies and both vascular death and noncancer mortality as outcome variables in a Cox regression analysis adjusted for age and sex. In contrast, the risk of cancer-related mortality was increased 2.6-fold., Conclusions: Anti-cardiolipin antibodies are associated with cancer mortality, likely as an epiphenomenon of malignancy, but they are not predictive of vascular mortality or noncancer mortality. Hence, although a clear association between anti-cardiolipin antibodies and (mostly nonfatal) vascular events has been described in the literature, our data indicate that this finding is not necessarily associated with an increase in vascular mortality.

Increased levels of interleukin-6 (IL-6) have been reported in patients with a history of venous thromboembolism (VTE); however, prospective studies did not confirm an association between inflammatory markers that are highly correlated with IL-6 and the risk ofVTE. It was the aim of our study to investigate the association of IL-6 and its promoter polymorphism (-174) G > C with the risk of spontaneousVTE. IL-6 was measured in 128 patients with deep venous thrombosis (DVT,70 w/58 m),105 with pulmonary embolism (PE, 58 w/47 m) and 122 healthy controls (60 w/62 m) with a highly sensitive ELISA (Quantikine HS Human IL-6 Immunoassay, RnDSystems). The promoter polymorphism was determined by genotyping, allele specific PCR was followed by high resolution gel-electrophoresis. Median concentrations [interquartile ranges] were 2.37 [1.51-3.89] (pg/ml) in patients with DVT, 2.83 [1.83-4.87] in those with PE and 2.51 [1.71-4.78] in controls (p = 0.6, p = 0.4). Hetero- or homozygous carriers of the C allele (71% in DVT, 67% in PE and 59% among controls) did not have higher IL-6 levels than homozygous carriers of the G allele (median 2.60 vs. 2.59 pg/ml, p = 0.7). In conclusion, we found no association of IL-6 and its promoter polymorphism (-174) G > C with the risk of spontaneous VTE.

Background and Objectives: Haptoglobin (Hp) is a plasma protein that binds free hemoglobin and thus prevents catalysis of reactive oxygen species by the Fenton reaction. A genetic polymorphism has been described that leads to the generation of two distinct alleles, Hp1 and Hp2, which define three major haptoglobin phenotypes, denoted Hp1-1, Hp2-1 and Hp2-2. Hp2-2 has been reported to be associated with the risk of atherosclerosis and coronary heart disease. In our study we investigated the association of haptoglobin genotype and phenotype with the risk of spontaneous venous thromboembolism (VTE)., Design and Methods: One hundred and twenty-eight patients with a history of spontaneous deep vein thrombosis (70 women, 58 men), 105 with spontaneous symptomatic pulmonary embolism (58 women, 47 men) and 122 healthy controls (60 women, 62 men) were enrolled. Haptoglobin levels were measured immunonephelometrically and phenotypes were detected by polyacrylamide gel electrophoresis and subsequent immunoblotting., Results: The Hp2-2 phenotype was significantly more prevalent in patients (42%) than in controls (30%) and significantly increased the risk for VTE in univariable (odds ratio=1.6, 95% confidence interval [1.0-2.6], p=0.04) and multivariable analyses (odds ratio=1.9 [1.0-3.4], p=0.04). Hp2-2 (n=134) was associated with significantly lower haptoglobin levels (median=89.7 mg/dL) than Hp2-1 (n=170, median = 123.5 mg/dL, p<0.001) or Hp1-1 (n=51, median=142.8 mg/dL, p<0.001)., Interpretation and Conclusions: Our study gives the first evidence that Hp2-2 represents a risk factor for spontaneous VTE, presumably through a pathophysiological mechanism similar to that in arterial disease.

Background: Lupus anticoagulant (LA) is a strong risk factor of thrombosis. However, a subgroup of patients positive for LA is unaffected by thrombosis and currently no predictive markers are available to identify patients positive for LA at increased risk for thrombosis., Objective: The aim of the study was to investigate whether anti-beta-2-glycoprotein I (anti-beta2GPI) or anticardiolipin antibodies (ACA) are associated with an increased risk of thrombosis in patients persistently positive for LA., Patients and Methods: A cohort of 87 consecutive patients persistently positive for LA was investigated, 55 with and 32 without a history of thrombosis. Immunoglobulin G (IgG) and M (IgM) antibodies against beta2GPI and cardiolipin were determined by enzyme-linked immunoassay., Results: Patients positive for LA with thrombosis had significantly higher levels of anti-beta2GPI IgG (median 16.7 standard units, interquartile range 3.0-75.2, P = 0.002) and of ACA IgG (41.1 IgG phospholipid units per mL, 8.9-109.0, P = 0.002) than those without thrombosis (2.6, 1.4-7.9 and 9.7, 4.6-22.1, respectively). Levels of anti-beta2GPI IgM and ACA IgM did not differ significantly between LA patients with and without thrombosis (P = 0.25 and 0.12, respectively). Elevated anti-beta2GPI IgG was associated with an increased risk for thrombosis (OR = 4.0, 95% CI 1.2-13.1), especially for venous thromboembolism (OR = 5.2, 95% CI 1.5-18.0)., Conclusions: Increased levels of anti-beta2GPI IgG were associated with thrombosis. We conclude that anti-beta2GPI IgG levels above normal predict an increased risk of thrombosis in patients persistently positive for LA.

Objective: The underlying mechanism of the prothrombotic state associated with the lupus anticoagulant (LAC) has not been fully elucidated. Evidence suggests involvement of inflammation in arterial and venous thrombosis, and it may be hypothesized that subclinical inflammation aggravates the tendency to thrombosis in patients with LAC., Methods: Levels of high sensitivity C-reactive protein (hs-CRP), fibrinogen, and factor VIII (VIII) were measured in 38 patients with LAC and a history of thrombosis, 27 with LAC and no history of thrombosis, and 33 healthy controls., Results: Hs-CRP, fibrinogen, and factor VIII levels were significantly higher in patients with LAC with thrombosis (hs-CRP median = 0.3 mg/dl, interquartile range, IQR, 0.11-0.62, p < 0.001 vs controls; fibrinogen mean = 395 +/- 90 SD mg/dl, p < 0.001; factor VIII mean = 181 +/- 50%, p = 0.005) as well as in those without thrombosis (median = 0.21, IQR 0.10-0.12, p < 0.001; mean = 378 +/- 91, p = 0.003; mean = 179 +/- 39, p = 0.015) compared to controls (median = 0.07, IQR 0.03-0.12; mean = 308 +/- 48; mean = 137 +/- 39). After adjustment for age, body mass index, smoking status, and blood group (only for factor VIII) the differences between LAC groups and controls remained significant, except for the comparison of fibrinogen between patients without thrombosis and controls. The association between LAC and markers of inflammation was confirmed using linear regression analysis. Markers of systemic inflammation did not differentiate between LAC patients with and without thrombosis (p = 0.829 for hs-CRP, p = 0.649 for fibrinogen, p = 0.996 for factor VIII)., Conclusion: Our results show that LAC is associated with an inflammatory state. However, there was no evidence for an association between inflammatory markers and thromboembolism in patients with LAC.

The role of C-reactive protein (CRP) in venous thromboembolism (VTE) is still under discussion because of controversial results in the literature. Conflicting data may have partly been due to bias by exogenous factors altering CRP levels. We investigated CRP concentrations in patients with spontaneous VTE applying a study design that allowed the measurement of basal high sensitivity (hs)-CRP levels. Patients with a history of deep vein thrombosis (DVT, n=117) and pulmonary embolism (PE, n=97) were compared to healthy individuals (n=104). Hs-CRP levels (mg/dl) were significantly higher in patients (n=214, median/interquartile range: 0.171/0.082-0.366) than in controls (0.099/0.053-0.245, p=0.001). The unadjusted odds ratio (OR) for VTE per 1 mg/dl increase of CRP was 2.8 [95% confidence interval (CI): 1.1-6.8, p=0.03]. This association remained significant after adjustment for factor V Leiden, prothrombin G20210A and factor VIII activity above 230% (OR = 2.9, 95% CI [1.1-7.5]), but became remarkably attenuated and lost its statistical significance after adjustment for BMI alone (OR = 1.7 [0.7-4.0]). CRP was also not independently associated with VTE in subgroups of patients (those with DVT without symptomatic PE, those with PE and patients without established risk factor) in multiple regression analysis. In summary, we observed significantly higher basal hs-CRP levels in patients with spontaneous VTE compared to healthy controls. This association was independent of hereditary and laboratory risk factors for VTE, but lost its significance after adjustment for BMI. Increased basal CRP levels do not appear to represent an independent risk factor for VTE.