H. K. Nieuwenhuis

Patients with antiphospholipid antibodies and venous thrombosis should receive long term anticoagulant treatment.

OBJECTIVE--To determine whether the finding of antiphospholipid antibodies in patients with venous thromboembolic episodes should influence the duration of treatment with anticoagulant drugs by mouth. METHODS--A retrospective study was carried out in 19 patients with antiphospholipid antibodies and a history of venous thromboembolic episodes. The median follow up from the first venous thromboembolic episode was 93 months and the median age at this episode was 26 years. The patients had in total 34 venous thromboembolic episodes. The total follow up period comprised 32 periods with and 23 periods without anticoagulant drugs. RESULTS--The probability of being free of recurrent venous thromboembolic episodes, calculated by the Kaplan-Meier method, was significantly influenced by the use of anticoagulant drugs. Patients receiving oral anticoagulants had at eight years a 100% probability of survival without recurrence, whereas patients in whom anticoagulant drugs were stopped had a 50% probability of a recurrent venous thromboembolic episode at two years, and a 78% probability of recurrence at eight years. CONCLUSION--Patients with venous thromboembolic episodes and antiphospholipid antibodies have a high risk for recurrent venous thromboembolic episodes and long term treatment with anticoagulant drugs by mouth is an effective prophylaxis.

Recombinant factor VIIa reverses the in vitro and ex vivo anticoagulant and profibrinolytic effects of fondaparinux.

Summary.  Background: Fondaparinux is a synthetic pentasaccharide, which selectively inhibits coagulation factor (F) Xa, and is registered for prevention of venous thromboembolism following hip fracture, hip replacement, and knee replacement surgery. Recently, it was shown that recombinant FVIIa (rFVIIa) reverses anticoagulant effects of fondaparinux in healthy volunteers. Objectives: In this study, we have explored the in vitro and ex vivo effects of rFVIIa on clot formation and thrombin‐activatable fibrinolysis inhibitor (TAFI)‐mediated down‐regulation of fibrinolysis after fondaparinux administration. Methods: In vitro clot lysis assays were performed in pooled normal plasma from healthy volunteers to which fondaparinux was added, and in serial samples from healthy volunteers who received a single bolus dose of fondaparinux, a single bolus dose of rFVIIa, or both. Results and conclusions: Fondaparinux significantly delayed clot formation, and clot lysis was significantly increased due to decreased activation of TAFI. Addition of recombinant FVIIa corrected the inhibited clot formation induced by fondaparinux, and the acceleration of clot lysis was partially reversed. In vivo administration of fondaparinux (10 mg) to healthy volunteers similarly resulted in accelerated plasma clot lysis. Subsequent administration of rFVIIa (90 µg kg−1) normalized the clot lysis time up to 6 h postadministration. rFVIIa might be a good therapeutic option in patients treated with fondaparinux who develop bleeding complications, since both clot formation as well as fibrinolytic resistance are improved.

Risk factors for thrombosis in lupus patients

Lupus anticoagulant, concentrations of anticardiolipin antibodies, antithrombin III, plasminogen, (free) protein S, protein C, prothrombin, platelet counts, and bleeding times were determined in 74 lupus patients (58 with systemic lupus erythematosus; 16 with lupus-like disease) to establish the presence of risk factors for thrombosis in these patients. Of the variables evaluated, lupus anticoagulant had the strongest association with a history of thrombosis. Both positive anticardiolipin antibody concentrations and the presence of (mild) thrombocytopenia were significantly associated with a history of thrombosis and the presence of lupus anticoagulant. Reduced concentrations of antithrombin III, plasminogen, (free) protein S, and protein C were found in some patients but were not associated with either thrombosis or lupus anticoagulant. Mean concentrations of total protein S were significantly lower in patients with thrombosis than in those without and in patients with lupus anticoagulant than in those without. The antigenic concentration of prothrombin was reduced in 3/74 (4%) lupus patients. These three patients had lupus anticoagulant but no history of thrombosis, which suggests that a low prothrombin concentration protects patients with lupus anticoagulant from the development of thrombosis. A prolonged bleeding time was associated with the presence of lupus anticoagulant but not with a history of thrombosis. Analysis by stepwise logistic regression did not disclose additional risk factors for thrombosis in lupus patients with lupus anticoagulant. Increased antithrombin III concentrations and decreased free protein S concentrations are often found in lupus patients, unrelated to lupus anticoagulant or thrombosis.

Autologous bone marrow transplantation for adult poor-risk lymphoblastic lymphoma in first remission.

PURPOSE Adult patients with poor-risk lymphoblastic lymphoma (LBL) treated with intensive multiagent chemotherapy (acute lymphoblastic leukemia [ALL]-like regimens) have a poor prognosis, with a disease-free long-term survival rate of less than 20%, caused by a very high relapse rate. Thus, adult patients with poor-risk LBL are candidates for alternative intensive consolidation therapy. PATIENTS AND METHODS Nine adult patients with poor-risk LBL in first remission after treatment with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP; six patients) or ALL-like regimens (three patients), were treated with high-dose cyclophosphamide and total body irradiation (TBI) followed by nonpurged autologous bone marrow transplantation (ABMT). RESULTS Two of nine patients relapsed at 4 and 8 months, respectively, after BMT, and one patient died of acute myeloblastic leukemia (AML) 7 months after ABMT without recurrence of his lymphoma. Six patients are in unmaintained first remission with a follow-up of 12 to 113 months (median, 53 months) after transplantation. CONCLUSIONS These results suggest that intensive consolidation therapy with high-dose cyclophosphamide and TBI followed by nonpurged ABMT may improve the long-term prognosis of this disease.

The usefulness of five D-dimer assays in the exclusion of deep venous thrombosis.

Summary.  d‐Dimer measurement is a promising tool in the exclusion of venous thrombosis. New d‐dimer assays have been introduced, but need clinical validation. Our objective was to evaluate the clinical usefulness of four relatively new d‐dimer assays and a classical ELISA in outpatients suspected for deep venous thrombosis. In 537 patients, participants in a large prospective management study using a clinical probability score and a d‐dimer measurement (Tina‐quant®), additional samples were taken for d‐dimer measurement using the Asserachrom ELISA®, the VIDAS New®, the STA‐LIA® and the Miniquant® assay. Performances of each test were calculated using clinical data during a 3‐month follow‐up. Thrombosis was detected in 224 patients (42%). The area under the ROC curve was significantly higher for the Tina‐quant as compared to the other assays. Using standard cut‐off values, sensitivity, negative predictive value (NPV) and specificity of the Asserachrom were 97, 94 and 33%, respectively. For the VIDAS New, values were 100, 96 and 8%, respectively. The Tina‐quant showed values of 99, 98 and 41%, respectively, and the STA‐LIA 98, 95 and 32%. Values for the Miniquant were 95, 94 and 52%. The d‐dimer assays in our study all show a high sensitivity and negative predictive value, but none of the assays reached an NPV of > 98% at standard cut‐off values. d‐Dimer assays with a low specificity still necessitate additional diagnostic tests in the majority of the patients.

Absence of ligands bound to glycoprotein IIB-IIIA on the exposed surface of a thrombus may limit thrombus growth in flowing blood.

We examined the distribution of glycoprotein IIb-IIIa (GPIIb-IIIa) and its ligands fibrinogen and von Willebrand factor (vWf) on platelets which had adhered under flow conditions. Immunoelectron microscopy was performed on whole mounts and frozen thin sections of adhering platelets. GPIIb-IIIa was homogeneously distributed on dendritic platelets and on interplatelet membranes of formed thrombi. Fibrinogen and vWf were predominantly associated with interplatelet membranes and membranes facing the substrate. On whole mounts, vWf appeared in clumps and linear arrays, representing the tangled or extended forms of the multimeric molecule. From semiquantitative analysis, it appeared that fibrinogen and vWf were, respectively, nine- and fourfold higher on interplatelet membranes than on surface membranes facing the blood stream, while GPIIb-IIIa was evenly distributed over all platelet plasma membranes. Ligand-induced binding sites (LIBS) of GPIIb-IIIa, as measured with conformation specific monoclonal antibodies RUU 2.41 and LIBS-1, were present on the surface of adhered platelets and thrombi. A redistribution of LIBS-positive forms of GPIIb-IIIa towards interplatelet membranes was not observed. Our data support the hypothesis that, under flow conditions, ligands have first bound to activated GPIIb-IIIa but this binding is reversed on the upper surface of adhering platelets. This relative absence of ligands on the exposed surface of thrombi may play a role in limiting their size.

Salvage therapy with ProMACE-MOPP followed by intensive chemoradiotherapy and autologous bone marrow transplantation for patients with non-Hodgkin's lymphoma who failed to respond to first-line CHOP.

PURPOSE We used alternative chemotherapy immediately followed in early-response patients by high-dose chemoradiotherapy and autologous bone marrow transplantation (ABMT) to treat patients with non-Hodgkins lymphoma (NHL) who had failed to respond to first-line chemotherapy. PATIENTS AND METHODS Thirty-one patients with NHL of intermediate- or high-grade malignancy who had failed to respond to first-line cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) chemotherapy were treated. Seventeen patients had primary refractory disease and 14 had relapsed from first complete response (CR). The treatment consisted of prednisone, methotrexate, doxorubicin, cyclophosphamide, etoposide, mechlorethamine, vincristine, and procarbazine (ProMACE-MOPP) salvage chemotherapy, followed, in case of responsive disease (at least partial response [PR]), by high-dose cyclophosphamide and total-body irradiation (TBI) with ABMT. RESULTS Twenty-eight of 31 (90%) patients achieved PR (23 patients) or CR (five patients) with ProMACE-MOPP, and three failed to respond. Seventeen of 28 (61%) patients who responded underwent the ABMT procedure, which resulted in CR in 14 patients (82%); three failed to respond. Eleven responsive patients were not transplanted because of residual bone marrow infiltration (five patients), patient refusal (four patients), and ProMACE-MOPP-related mortality (two patients). To date, nine patients are alive and in CR, seven with a median follow-up of 41 months (range, 17 to 84 months). Referring to the original CHOP treatment, five of 17 (29%) patients with primary refractory disease remain free of disease at a median of 36 months after ABMT, and four of 14 (29%) patients in first relapse remain free of disease at a median of 33 months after ABMT. One patient died of AMBT-related toxicity. CONCLUSION ProMACE-MOPP salvage chemotherapy produces a high early-response rate in patients who fail to respond to first-line CHOP, and more than half of the responding patients can be scheduled to receive ABMT, resulting in disease-free survival (DFS) at 3 years in 50% of the transplanted patients and in 25% of the original number of patients intended to receive this treatment.

Aggregate formation is more strongly inhibited at high shear rates by dRGDW, a synthetic RGD-containing peptide.

The effect of D-Arg-Gly-Asp-Trp (dRGDW), a synthetic RGD-containing peptide, on platelet adhesion and aggregate formation on various purified adhesive proteins and the extracellular matrix of endothelial cells was investigated with anticoagulated blood recirculating through a parallel-plate perfusion chamber. Aggregate formation on the extracellular matrix of phorbol myristate acetate (PMA)-stimulated endothelial cells and on collagen type I was more strongly inhibited by dRGDW at higher shear rates than at a low shear rate. Platelet adhesion to the extracellular matrix of nonactivated and PMA-stimulated endothelial cells was inhibited by dRGDW, especially at high shear rates, probably as a consequence of the inhibition of platelet spreading. Inhibition by dRGDW of platelet adhesion to von Willebrand factor, fibronectin, and fibrinogen was almost complete, indicating that platelet adhesion to these substrates is mediated through RGD-directed receptors. Platelet adhesion to laminin was not inhibited by the peptide, whereas platelet adhesion to collagen was increased as a consequence of the inhibition of aggregate formation. Our results show that dRGDW is a strong inhibitor of platelet adhesion and aggregate formation, especially at high shear rates.