Silvia Koder

High plasma levels of soluble P-selectin are predictive of venous thromboembolism in cancer patients - results from the Vienna Cancer and Thrombosis Study (CATS)

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.

Microparticle-associated tissue factor activity in patients with metastatic pancreatic cancer and its effect on fibrin clot formation

Highly elevated microparticle (MP)-associated tissue factor (TF) activity was found in patients with pancreatic cancer, one of the most prothrombotic malignancies. It remains to be elucidated whether MP-TF activity reflects the prothrombotic state in these patients. MP-TF activity levels and the TF-dependent and -independent effect of MPs on fibrin clot formation were determined in patients with metastatic pancreatic cancer (n = 27), in healthy individuals (n = 10) and in plasma samples from lipopolysaccharide (LPS)-stimulated blood (LPS-plasma), which is rich in monocyte-derived TF-bearing MPs. The median MP-TF activity was 1.06 pg/mL (range, from 0.19 to 10.34 pg/mL) in patients with pancreatic cancer, 0.61 pg/mL (range, from 0.36 to 0.79 pg/mL) in LPS-plasma, and 0.18 pg/mL (range, from 0.04 to 0.39 pg/mL) in healthy individuals. MPs derived from LPS-plasma had the strongest impact on fibrin clot formation time (median, 157.6 seconds; range, from 149.5 to 170.4 seconds). Fibrin clot formation occurred significantly later in MPs derived from patients with pancreatic cancer (median, 273.4 seconds; range, from 146.6 to 354.4 seconds; P < 0.001) and in healthy individuals (median, 299.0 seconds; range, from 261.1 to 417.9 seconds; P < 0.001). Only in MPs derived from LPS-plasma the fibrin clot formation time dependent strongly on TF (median prolongation after TF blockade: 68% in LPS-plasma, 10% in patients with pancreatic cancer, and 4% in healthy individuals). In conclusion, highly elevated MP-TF activity was found in patients with metastatic pancreatic cancer, but TF-bearing MPs had a small effect on fibrin clot formation. TF-bearing MPs might not be the main mediators of the prothrombotic state associated with pancreatic cancer. However, the small but significant increase in coagulation potential by TF-bearing MPs might contribute to the multifactorial pathogenesis of venous thromboembolism in pancreatic cancer.

P-selectin gene haplotypes modulate soluble P-selectin concentrations and contribute to the risk of venous thromboembolism

The cell adhesion molecule P-selectin mediates the interaction of activated platelets or endothelial cells with leukocytes. In arterial and venous thromboembolism (VTE) increased soluble P-selectin (sP-selectin) concentrations have been found, and associations of P-selectin genotypes with thrombotic disease have been proposed. We assessed the effect of four single nucleotide polymorphisms (SNPs) [one in the promoter region (c.-2123C>G) and three (S290N, c.1087G>A; D562N, c.1902G>A; T715P, c.2363A>C) in the coding region] and the calculated haplotypes in the P-selectin gene (SELP) on sP-selectin concentrations and VTE risk. The analysis was carried out in 116 high-risk patients with a history of objectively confirmed recurrent VTE and 129 age- and sex-matched healthy individuals. Haplotypes were generated using computer-assisted haplotype reconstruction with Phase 2.1. sP-selectin (microg/l) was measured by ELISA. Frequencies of all four individual SNPs were not statistically significantly different between patients and controls. Ten haplotypes were obtained for the control population, and nine for the patient group. The most frequent haplotype among controls was CGGA (major allele at all positions) (27.8%; frequency in patients 19.0%), which was used as reference for statistical analyses. Among patients GGAA was most frequent (23.3%; frequency in controls 17.5%). Haplotypes were significantly associated with sP-selectin concentrations in patients and in controls (p<0.001 and p=0.011). Compared to CGGA some but not all haplotypes conferred an increased risk for VTE with odds ratios (ORs) between 5.4 (95% CI: 2.5-12.2) for CAGA, 3.3 (1.2-9.2) for CGAC, and 2.4 (1.3-4.7) for GGAA. All ORs remained statistically significant after adjustment for the factor V Leiden mutation, located in close proximity to SELP on chromosome 1, as well as all other established risk factors for VTE. In conclusion, SELP haplotypes modulate plasma concentrations of sP-selectin and affect the risk of recurrent VTE.

Impact of environmental and hereditary risk factors on the clinical manifestation of thrombophilia in homozygous carriers of factor V:G1691A

Summary.  Background: Limited data exist on the clinical manifestations of homozygous factor (F)V:G1691A mutation (FV Leiden) and the impact of environmental and genetic risk factors. Objectives: To assess the contribution of these factors on the thrombophilic phenotype. Patients and methods: In a retrospective multicenter cohort study 165 individuals with homozygous FV:G1691A mutation, of whom 129 had previous venous thromboembolism (VTE), were included. To study the role of environmental risk factors, patients were compared by the use of a standardized questionnaire to 165 sex‐ and age‐matched individuals (reference group A); of these, two had previous VTE. To assess the role of genetic risk factors, factor (F)II:G20210A and MTHFR:C677T were determined in individuals homozygous for FV:G1691A and in 177 healthy individuals without previous VTE (reference group B). Results: The first VTE occurred significantly earlier in women (median age 25 years) than men (35.5 years). In 81% of women and 29% of men an environmental risk factor was present before first VTE. Oral contraceptives increased the risk of thrombosis 4‐fold [odds ratio (OR) 4.0, 95% confidence interval (CI) 1.7, 10.4] in women with homozygous FV:G1691A. Postoperative and post‐traumatic VTE as first manifestation occurred in 13% and 15% of surgical/traumatic events in patients and in 0.7% and 1.8% in reference group A, respectively (OR 19.7, 95% CI 2.5, 154 and OR 9.2, 95% CI 1.1, 79.4). Heterozygous FII:G20210A was more prevalent in symptomatic patients (11.7%) compared with reference group B (2.8%, OR 4.6, 95% CI 1.6, 13.2). The prevalence of homozygous MTHFR:C677T genotype was similar in patients and reference group B. Conclusions: Our study supports the concept of thrombophilia as a multifactorial disorder. The knowledge of coexisting factors predisposing to VTE is useful for medical advice for primary and secondary prophylaxis in these patients.

Increased mortality in patients with the lupus anticoagulant: the Vienna Lupus Anticoagulant and Thrombosis Study (LATS)

Data on the clinical course of lupus anticoagulant (LA)-positive individuals with or without thrombotic manifestations or pregnancy complications are limited. To investigate mortality rates and factors that might influence mortality, we conducted a prospective observational study of LA-positive individuals. In total, 151 patients (82% female) were followed for a median of 8.2 years; 30 of the patients (20%) developed 32 thromboembolic events (15 arterial and 17 venous events) and 20 patients (13%) died. In univariable analysis, new onset of thrombosis (hazard ratio [HR] = 8.76; 95% confidence interval [CI], 3.46-22.16) was associated with adverse survival. Thrombosis remained a strong adverse prognostic factor after multivariable adjustment for age and hypertension (HR = 5.95; 95% CI, 2.43-14.95). Concomitant autoimmune diseases, anticoagulant treatment at baseline, or positivity for anticardiolipin- or anti-β2-glycoprotein I antibodies were not associated with mortality. In a relative survival analysis, our cohort of LA positives showed a persistently worse survival in comparison with an age-, sex-, and study-inclusion-year-matched Austrian reference population. The cumulative relative survival was 95.0% (95% CI, 88.5-98.8) after 5 years and 87.7% (95% CI, 76.3-95.6) after 10 years. We conclude that occurrence of a thrombotic event is associated with higher mortality in patients with LA. Consequently, the prevention of thromboembolic events in LA positives might improve survival.

Soluble Vascular Endothelial Growth Factor (sVEGF) and the Risk of Venous Thromboembolism in Patients with Cancer: Results from the Vienna Cancer and Thrombosis Study (CATS)

Purpose: Cancer patients are at an increased risk of venous thromboembolism (VTE). VEGF promotes the growth of highly thrombogenic tumor vessels. Here, we explored the utility of soluble plasma VEGF-A (sVEGF) as a biomarker for the prediction of VTE in patients with cancer. Experimental Design: Eight hundred four patients with newly diagnosed cancer or progression after remission were prospectively followed for 2 years until the occurrence of VTE or death [tumor sites: brain (n = 87), breast (n = 137), lung (n = 120), gastrointestinal (n = 143), pancreas (n = 53), prostate (n = 95), kidney (n = 22), myeloma and lymphoma (n = 99), and others (n = 48)]. Primary endpoint was symptomatic or fatal VTE. sVEGF was measured by immunoassay in baseline plasma. Results: Fifty-five patients developed VTE (6.8%) and 364 patients (45.3%) died. Five-hundred and forty-two (68.3%) participants had sVEGF levels above the detection limit of 0.5 pg/mL. The median sVEGF level (25th–75th percentile) was 8.1 pg/mL (0–17.7). The cumulative 2-year incidence of VTE was 10.2% [95% confidence interval (CI), 6.4–14.9] in patients with sVEGF greater than the 75th percentile of the sVEGF distribution (Q3, cutoff: 17.7 pg/mL), and 5.9% (95% CI, 4.2–7.9) in patients with lower levels (P = 0.03). The corresponding 2-year risk of death was 52.8% (95% CI, 46.0–60.0) and 43.9% (95% CI, 40.0–48.0), respectively (P = 0.02). In univariable time-to-VTE regression, elevated sVEGF was associated with VTE [subhazard ratio (SHR) per 10 pg/mL increase, 1.04; 95% CI,1.00–1.09; P = 0.04)]. The association between sVEGF and risk of VTE prevailed after multivariable adjustment for high-risk tumor sites, age, gender, factor VIII, thrombin generation potential, and soluble P-Selectin (adjusted SHR, 1.04; 95% CI, 1.00–1.09, P = 0.05). Conclusions: Elevated sVEGF is associated with an increased risk of VTE in patients with cancer. Clin Cancer Res; 22(1); 200–6. ©2015 AACR.

Thrombin generation in type 2 diabetes with albuminuria and macrovascular disease.

Eur J Clin Invest 2012; 42 (5): 470–477

Platelet activation and function during eltrombopag treatment in immune thrombocytopenia

We monitored platelet activation by means of P-selectin and platelet monocyte aggregates (PMA) and platelet function by whole blood multiple electrode aggregometry and platelet adhesion under high shear in chronic immune thrombocytopenia patients to define changes in platelet activation during treatment with eltrombopag. Overall, platelet activation and function normalized with increasing platelet counts. However, P-selectin, which was already elevated before treatment, and PMA increased further transiently during the first weeks. The increases in P-selectin and in PMA indicate ongoing platelet activation during the early period of treatment.

Association of platelet activation markers with cancer-associated venous thromboembolism

Abstract Venous thromboembolism (VTE) is a frequent complication in cancer patients. Platelet activation is thought to be involved in cancer-associated VTE. Here, we determined the association between evolving markers of platelet activation (soluble P-selectin [sP-selectin], soluble CD40 ligand [sCD40L], thrombospondin-1 [TSP-1] and platelet factor-4 [PF-4]) and the development of cancer-associated VTE. A nested matched case–control study was applied within a cohort of 1779 patients with different types of cancer that had been included in the Vienna Cancer and Thrombosis Study (CATS), a prospective, observational study on patients with newly diagnosed or progressive cancer after remission. Primary endpoint is symptomatic VTE during a maximum follow-up of 2 years. Cases (patients who developed VTE during follow-up) were matched in a 1:2 ratio to controls without VTE during follow-up with respect to tumor type, stage and time of observation in the study. In total, 131 VTE cases were compared to 262 controls. In logistic regression analysis, only sP-selectin was associated with risk of VTE. The odds ratios (OR) per double increase of sP-selectin, sCD40L, TSP-1 and PF-4 were 1.66 (95% confidence interval: 1.17–2.35, p = 0.005), 1.04 (0.89–1.21, p = 0.635), 1.09 (0.90–1.32, p = 0.360) and 1.03 (0.87–1.21, p = 0.737), respectively. In conclusion, sP-selectin, but not sCD40L, TSP-1 or PF-4 were associated with risk of VTE in cancer patients in this nested case–control study.

Thrombin generation in patients with a bleeding tendency of unknown origin

There are a number of persons with a mild to moderate bleeding tendency, in whom no underlying bleeding disorder can be detected despite thorough investigation of all known heritable and acquired haemostatic abnormalities. Thrombin is the central enzyme in the coagulation cascade, which is important for sufficient haemostasis. The measurement of an individuals potential to generate thrombin has been proposed for estimating the individual coagulation potential and predicting a hyper- or hypo-coagulable phenotype. The aim of our study was to investigate in vivo thrombin generation in a case-control study of patients with a bleeding tendency of unknown origin and in age- and sex-matched healthy individuals. Bleeding tendency was classified according to a standardized bleeding score. Thrombin generation was measured with a commercially available assay (Technothrombin-TGA, Technoclone, Vienna, Austria). In total, 101 patients (76 female; median age [25th–75th percentile], 44 [35–60] years) and 102 controls (67 women; median age, 47 [38–55] years) were enrolled. The distribution of parameters of thrombin generation among patients and controls showed no statistically significant difference: lag phase (14.4 [11.1–18.1] vs. 14.1 [12.1–17.1] min, p = 0.720), peak thrombin (179.8 [135.6–242.6] vs. 175.1 [143.1–261.4] nM, p = 0.576), time to peak thrombin (23.6 [18.1–28.6] vs. 22.6 [18.6–27.1] min, p = 0.790), velocity index (19.7 [13.0–39.0] vs. 22.6 [14.5–36.5] nM/min, p = 0.233) and area under the thrombin generation curve (3,491 [3,069–3,880] vs. 3,414 [3,045–3,750] nM thrombin, p = 0.673). In conclusion, the thrombin generation potential in patients with a bleeding tendency of unknown origin was not different from that of healthy individuals.