[Haemostatic aspects in clinical oncology]. / Hämostaseologische Aspekte in der Onkologie.

The clinical link between cancer and thrombosis has been recognized by Armand Trousseau in 1865. It has now become clear that clotting activation in malignancy not only plays an important role in the evolution of venous thromboembolism (VTE) or systemic coagulation disorders such as disseminated intravascular coagulation, but that multiple components of the haemostatic and fibrinolytic systems are directly involved in tumour progression. In particular, tissue factor (TF) appears to be involved in several pathways relevant to cancer growth and metastasis. Increasing evidence emerges that haemostatic perturbances in cancer patients are, at least in part, controlled by defined genetic events in molecular tumourigenesis including activating and inactivating mutations of oncogenes and tumour suppressor genes, respectively. Long-term therapy with low-molecular-weight heparin (LMWH) is considered as standard treatment for cancer-associated VTE. However, several experimental studies and clinical trials suggest that LMWH may also be beneficial as an adjunct in the treatment of patients with malignant disease. This article provides an overview on the significance, pathogenesis and treatment of cancer-related clotting disorders as well as on the cellular and molecular mechanisms, by which haemostatic components such as TF, platelets and fibrin(ogen) drive tumour progression.

Experimental metastasis and primary tumor growth in mice with hemophilia A.

During experimental lung metastasis, tumor cells adhere to the pulmonary microvasculature and activate coagulation via surface-expressed tissue factor (TF), leading to local fibrin deposition and platelet aggregation. While interventional studies have demonstrated great efficacy of anticoagulants and antiplatelet agents in inhibiting metastasis, no information is available on how tumor biology may be affected by congenital bleeding disorders such as hemophilia A. We therefore used a syngeneic model to study experimental metastasis and primary tumor growth in factor VIII (FVIII)-deficient mice. By conventional reverse transcription-polymerase chain reaction, flow cytometry, and one-stage clotting assays, we demonstrated constitutive expression of TF mRNA, antigen, and procoagulant activity in the murine B16F10 melanoma cell line. In hemophilic mice, B16F10 lung metastasis was significantly (P < 0.001) enhanced by a single dose of human FVIII (100 U kg(-1)), suggesting that FVIII played a critical role during the early blood-borne phase of the metastatic cascade. In contrast, lung seeding was significantly (P < 0.05) reduced by lepirudin, a direct thrombin inhibitor, suggesting that thrombin generation contributed to pulmonary metastasis even in the absence of FVIII. Consistent with this finding, intravenous injection of B16F10 cell-evoked laboratory changes of a hemolytic thrombotic microangiopathy and consumptive coagulopathy in both hemophilic and non-hemophilic mice. Subcutaneous implantation of B16F10 cells into mice with hemophilia A gave rise to primary tumors in an exponential growth pattern similar to that observed in non-hemophilic mice. Although TF expression by B16F10 cells may promote thrombin-dependent metastasis in mice with hemophilia A, amplification of coagulation by host FVIII appears to be necessary for maximum lung seeding.

Non-overt disseminated intravascular coagulation in patients during treatment with antithymocyte globulin for unrelated allogeneic hematopoietic stem cell transplantation.

We assessed the effect of rabbit antithymocyte globulin manufactured by Fresenius (ATG-F) on the hemostatic system in patients (n=12) with various hematological malignancies undergoing hematopoietic stem cell transplantation (HSCT) from HLA-matched unrelated donors. For this purpose, we monitored different parameters of coagulation before, during and after the administration of ATG-F. As a control group, we recruited patients (n=10) undergoing HSCT from their HLA-identical siblings who did not receive ATG-F as part of their preparative regimens. At 24 and 48 h after ATG-F treatment had been initiated, we found a temporary rise in D-Dimer, tissue factor, soluble thrombomodulin and thrombin-antithrombin III complex levels and a significant decrease of platelet counts in patients treated with ATG-F as compared to the control group. No differences between the two groups could be detected with regard to global coagulation tests as well as the incidence of bleeding manifestations, thromboembolic complications or the development of vascular-occlusive-disease of the liver. This temporary state of a stressed but compensated coagulation system under ATG-F therapy can be addressed as nonovert disseminated intravascular coagulation (DIC). The effect was independent from the different conditioning regimens and eased off after cessation of ATG-F. We conclude that ATG-F can induce nonovert DIC in patients receiving antithymocyte globulin as part of their conditioning regimen for HSCT.

Exacerbation of antiphospholipid antibody syndrome after treatment of localized cancer: a report of two cases.

Patients with malignancy often present with a variety of coagulation abnormalities which may ultimately lead to recurrent arterial and venous thromboses. Recently the presence of antiphospholipid antibodies in cancer patients has been proposed as one of the potential mechanisms promoting hypercoagulability. Here we report two consecutive patients with localized tumors, one suffering from breast cancer and another presenting with colorectal cancer, who experienced dramatic exacerbation of the antiphospholipid antibody syndrome (APAS) within 4 weeks after surgery. In the first patient who had also received one course of adjuvant chemotherapy, major ischemic stroke and recurrent venous thromboembolism were paralleled by the development of ulcerative livedoid vasculitis and pancytopenia, constituting the diagnosis of systemic lupus erythematosus with secondary APAS. In the second patient, progressive thrombotic occlusion of the superior and inferior vena cava was associated with bilateral pulmonary embolism, acute renal failure, and disabling soft tissue edema. Although not fulfilling the classic criteria of "catastrophic" APAS, the clinical features were life threatening and appeared to be refractory to oral anticoagulation with phenprocoumon. In addition, a diagnosis of Trousseau's syndrome was unlikely due to missing evidence of gross metastatic disease. Besides a suggested treatment strategy comprising high doses of low-molecular-weight heparin, potential pathogenic mechanisms are discussed in consideration of a recently proposed "thrombotic storm," which may cause multiple thromboses after an initial provocation in patients with known hypercoagulability.

[Complicated antiphospholid antibody syndrome]. / Kompliziertes Antiphospholipidantikörper-Syndrom - Eine interdisziplinäre Herausforderung -

HISTORY AND CLINICAL FINDINGS: A 51-year-old female patient suffered from recurrent ischemic strokes and venous thromboembolism although treated with ASS and phenprocoumon, which mainly occurred after diagnosis and treatment of an invasive-ductal mamma carcinoma. The severely ill patient presented with right-sided hemiparesis and dysarthria, a swollen leg, a painful necrotic-ulcerative lesion at the left-lateral ankle and a systolic heart murmur. INVESTIGATIONS: Laboratory data revealed a haemoglobin of 8,4 g/dl, a leucocyte count of 3,1 x 10 (9)/l and a platelet count of 87 x 10 (9)/l. C-reactive protein, ESR and plasma fibrinogen were markedly increased. Levels of antinuclear, IgG-anticardiolipin and anti-doublestranded-DNA antibodies were excessively elevated. A test for lupus anticoagulant was strongly positive. Sonographic examinations showed deep vein thrombosis and significant mitral valve regurgitation. Suspected pulmonary embolism was demonstrated by CT scan. We diagnosed systemic lupus erythematosus with secondary antiphospholipid antibody syndrome (APAS). TREATMENT AND COURSE: Phenprocoumon was stopped and full-dose anticoagulation with low-molecular-weight heparin initiated. Additional immunosuppressive therapy consisted of cyclophosphamide, azathioprin and prednisone resulting in prevention of further thromboembolism and significant improvement of clinical symptoms. The observed severe interference of LA with the prothrombin time after cessation of phenprocoumon (INR 3,6; FII activity 81 %) suggested that the effect of oral anticoagulation had been overestimated in the past. CONCLUSION: APAS may present as an acute and life-threatening disorder. In this case interdisciplinary co-operation and a highly individualised treatment strategy are mandatory.

Enhanced platelet aggregation with TRAP-6 and collagen in platelet aggregometry in patients with venous thromboembolism.

The role of platelet hyperaggregability as a possible risk factor for venous thromboembolism is not well defined. Some authors described enhanced maximal platelet aggregation in platelet aggregometry as a contributing factor for arterial and venous thrombosis. This syndrome has been termed "sticky-platelet syndrome" (SPS). The diagnosis of SPS is based on the demonstration of platelet hyperaggregability in aggregometry after stimulation with epinephrine (EPI) and/or adenosine diphosphate (ADP). We investigated platelet hyperaggregability in platelet-rich plasma (PRP) of patients (n = 34) with unexplained venous thromboembolism in comparison to healthy individuals (n = 53). For analysis, platelet aggregometry was performed and the influence of epinephrine, adenosine diphosphate, collagen (Coll) and thrombin receptor-activated peptide (TRAP-6) as agonist were determined. Compared to the control group, patients with venous thromboembolism showed an enhanced maximal platelet aggregation with low concentrations of TRAP-6 (2 microM) and collagen (0.05 microM). In contrast, we could not detect an increased platelet aggregation with EPI or ADP. Our results indicate that platelet hyperaggregability may represent an independent risk factor in patients with otherwise unexplained venous thromboembolism. In our study, low concentrations of TRAP-6 and collagen are superior to EPI and ADP to define platelet hyperreactivity in platelet aggregometry.

Biocompatibility of a new cell separator studied by flow cytometry: analyses of platelet antigens during apheresis and storage.

BACKGROUND: Alterations of platelet antigens are known to occur during cytapheresis and storage. These changes have been shown to be dependent on the biomaterials, techniques, and devices used. In this study, the influence of a new cell separator (AMICUS) and storage container (PL-2410) on platelet glycoproteins was analyzed. STUDY DESIGN AND METHODS: During plateletpheresis and storage, the levels of platelet glycoproteins and binding of fibrinogen were determined by flow cytometry. RESULTS: During apheresis, mean channel fluorescence intensity of CD41 a did not change significantly (p = 0.06). A small increase was evident in CD42b mean channel fluorescence intensity, which rose from a baseline level of 178.6 +/- 68.3 to 231.5 +/- 97.9 at the end of the procedure (p<0.05); in CD62p-positive platelets, which increased from 2.0 +/- 0.9 percent to 9.9 +/- 3.9 percent (p<0.05); in CD63-positive platelets, which increased from 1.7 +/- 0.7 percent to 7.9 +/- 2.6 percent (p<0.05); and in the binding of fibrinogen, which increased from 1.9 +/- 0.8 percent positive platelets to 10.5 +/- 2.6 percent (p<0.05). During storage, the mean channel fluorescence intensity of CD41a and CD42b, the percentage of CD62p- and CD63-positive platelets, and the binding of fibrinogen to platelets showed no significant change. CONCLUSION: These studies show that alterations in platelet antigens and platelet activation occur to a small degree during apheresis and storage. These findings demonstrate generally good biocompatibility of this new cell separator.

[Intraoperative coagulation activity--a defined group of trauma surgery patients]. / Intraoperative Gerinnungsaktivierung--Untersuchungen an einem definierten Patientengut der Unfallchirurgie.

Analyses of blood coagulation in a defined group of patients before, during, and after trauma-surgery confirms an intraoperative trigger-mechanism, that causes postoperative thromboembolic complications. They also proof the correlation between extent of tissue-lesion and extent of triggering, this was previously presumed from the postoperative incidence of thromboembolic complications. Apart from the usual blood coagulation tests the following parameters where analysed: Factor VIII: C, Ristocetin-Co-factor, Factor Xa, AT III, TAT, Reptilase-time, tPA, D-dimers, and FPA. Simultaneously, it was shown, that a preoperative prophylaxis of thrombosis can prevent an intraoperative increase of Factor Xa, that plays a key role in postoperative thromboembolic complication. The increased intraoperative turnover of coagulation factors, which is necessary for physiologic blood coagulation, is not prevented.