A comparative analysis of different automated von Willebrand factor glycoprotein Ib-binding activity assays in well typed von Willebrand disease patients.

Essentials Von Willebrand ristocetin cofactor activity (VWF:RCo) is not a completely reliable assay. Three automated VWF activity assays were compared within a von Willebrand disease (VWD) cohort. Raw values for all three assays were virtually the same. An overall problem within type 2A/IIE VWD using VWF:GPIb-binding activity/VWF:Ag was observed. SUMMARY: Background von Willebrand disease (VWD) is an inherited bleeding disorder caused by quantitative (type 1 and 3) or qualitative (type 2) von Willebrand factor (VWF) defect. VWD diagnosis and classification require numerous laboratory tests. VWF: glycoprotein Ib (GPIb)-binding activity assays are used to distinguish type 1 from type 2 VWD. Objectives Three different automated VWF:GPIb-binding activity assays were compared. Patients and methods BC-VWF:RCo (Siemens Healthcare Diagnostics), HemosIL® VWF:RCo (Instrumentation Laboratory) and INNOVANCE® VWF:Ac (Siemens Healthcare Diagnostics) were performed in a well typed VWD cohort (n = 142). Results Based on the three most used VWD parameters (FVIII:C, VWF:Ag and VWF:GPIb-binding activity) and using a cut-off of <0.70 for type 2 VWD revealed sensitivity and specificity of, respectively, 92% and 72.4% for VWF:RCo/VWF:Ag, 84% and 89.7% for VWF:GPIbR/VWF:Ag, and 92% and 85.1% for VWF:GPIbM/VWF:Ag, whereas a lowered cut-off of < 0.60 resulted in reduced sensitivity with increased specificity for all assays. Conclusion VWD classification based on FVIII:C, VWF:Ag and VWF:GPIb-binding activity revealed an overall problem with normal VWF:GPIb-binding activity/VWF:Ag within type 2, especially type 2A/IIE. Although all assays were practically identical, BC-VWF:RCo had higher %CV compared with both new assays but comparable lower limit of quantification (LLOQ) ~4 IU dL-1 . No clear improved distinction between type 1 and 2 VWD with new assays was seen. BC-VWF: RCo and HemosIL® are ristocetin dependent, whereas INNOVANCE® does not rely upon ristocetin and is not influenced by VWF polymorphisms increasing VWF:GPIb-binding activity levels. INNOVANCE® seems to be the best choice as a first-line VWF:GPIb-binding activity assay, providing the best balance between sensitivity and specificity for type 2 VWD.

Duplex ultrasound, clinical score, thrombotic risk, and D-dimer testing for evidence based diagnosis and management of deep vein thrombosis and alternative diagnoses in the primary care setting and outpatient ward.

Deep vein thrombosis (DVT) has an annual incidence of 0.2% in the urban population. First episodes of calf vein thrombosis (CVT) and proximal DVT are frequently elicited by risk factors, including varicose veins, cancer, pregnancy/postpartum, oral contraceptives below the age of 50 years, immobility or surgery. Leg pain and tenderness in the calf and popliteal fossa on physical examination may result from other conditions than DVT labeled as alternative diagnosis (AD) Congenital venous thrombophilia is present in every third first DVT, increased FVIII in every fourth first DVT, and FV Leiden/FII mutation in 40% of women on oral anticonceptive pill before reaching the menopause. Routine thrombophilia testing for FV Leiden/prothrombin mutation and FVIII as main risk factor for venous thrombosis is recommended. Primary superficial venous thrombosis (SVT) and DVT patients with a autosomal dominant family history of DVT are candidates for thrombophilia testing for congenital AT, PC and PS deficiency. The requirement for a safe diagnostic strategy of CVT and DVT should be based on an objective post-test incidence of venous thromboembolism (VTE) of less than 0.1% with a negative predictive value for exclusion of DVT of 99.9% during 3 months follow-up. Modification of the Wells score by elimination of the "minus 2 points" for AD is mandatory and will improve the diagnostic accuracy of CVT/DVT suspicion in the primary care setting and outpatient ward. The sequential use of complete DUS, ELISA D-dimer testing and modified clinical Wells' score assessment is safe and effective for the exclusion and diagnosis of CVT, DVT and AD. About 10% to 20% of patients with DVT develop overt post-thrombotic syndrome (PTS) at one year post-DVT, and both PTS and DVT recurrences further increase to about 30% during long-term follow-up. Objective risk stratification of PTS complications using DUS for recanalization and reflux and D-dimer testing will become an integral part in routine clinical practice to assess the optimal duration of wearing medical elastic stockings and anticoagulation for the prevention DVT recurrence as the best option to reduce the incidence and costs of suffering from irreversible PTS.

Application of PRV-1 mRNA expression level and JAK2V617F mutation for the differentiating between polycytemia vera and secondary erythrocytosis and assessment of treatment by interferon or hydroxyurea.

Increased PRV-1 mRNA expression and the presence of Jak2(V617F) mutation in peripheral blood granulocytes are specific markers for chronic myeloproliferative disorders (MPD), which facilitate the differential diagnosis between polycythemia vera (PV) and secondary erythrocytosis (SE) and may be helpful for monitoring treatment efficacy in MPD patients. We evaluated the presence of the Jak2V617F mutation and increased PRV-1 mRNA expression along with previously established markers - erythropoietin (EPO) independent colony formation (EEC) and erythropoietin level for diagnosis of PV and assessment of treatment efficiency. Increased PRV-1 expression was found in 37 out of 46 patients diagnosed with PV (80%), in 4 out of 15 patients diagnosed with essential thrombocythemia (ET) (27%) and in 4 out of 8 patients with chronic idiopathic myelofibrosis (CIMF) (50%), and increased PRV-1 expression plus EEC formation was observed in 19 of 36 examined MPD patients indicating the superiority of PVSG and WHO bone marrow criteria for the diagnosis of ET, PV and CIMF. We could confirm a very high sensitivity, specificity and utility of the Jak2(V617F) mutation for differential diagnosis between PV and SE. Spontaneous EEC, serum EPO levels, PRV-1 expression was evaluated in 22 PV patients who carried the Jak2(V617F) mutation. A concordance of increased PRV-1 expression and presence of Jak2(V617F) mutation in 19/22 (85%); of increased PRV-1/Jak2/EEC in 14/22 (63%); and of Jak2/PRV-1/EEC/low Epo level in 10/22 (45%) patients was found indicating the superiority of the presence of Jak2(V617F) mutation for the diagnosis of PV. IFN-alpha therapy in patients with PV was more effective then hydroxyurea treatment and significantly reduced increased PRV-1 expression together with higher levels of Jak2(V617F) mutation (50-100%) in PV patients treated with hydroxy urea (HU) and lower levels of Jak2(V617F) mutation (35-90%) in PV patients treated with IFN-alpha. Normal PRV-1 expression level was observed in 44% of PV patients who achieved clinical remission and only in 3% of patient who did not. These preliminary observations indicate that the Jak2(V617F) mutation in particular and PRV-1 overexpression appear to be suitable markers for monitoring treatment efficiency in prospective randomised clinical studies comparing pegylated interferon and hydroxyurea in well defined PV patients with a clear indication for cytoreductive therapy.

JAK2(V617F) positive early stage myeloproliferative disease (essential thrombocythemia) as the cause of portal vein thrombosis in two middle-aged women: therapeutic implications in view of the literature.

The present study describes portal vein thrombosis (PVT) in two women as the first and single presenting symptom of latent or masked myeloproliferative disease (MPD). Essential thrombocythemia (ET) was suspected by a sustained increase in platelet count (>400 x 10(9)/l) and slight splenomegaly on echogram. ET could be diagnosed by the presence of large platelet in peripheral blood smear, an increase in clustered large megakaryocytes in bone marrow smear and the presence of the JAK2(V617F) mutation. A subsequent biopsy specimen was consistent with the diagnosis of true ET. In patients with a first episode of splanchnic vein thrombosis (SVT), analysis of any venous thrombophilic risk factors as well as a JAK2(V617F) mutation status indicative for MPD is warranted. Administration of heparin followed by oral anticoagulation with vitamin K antagonists is the treatment of choice in patients with SVT. Anticoagulation therapy combined with low-dose aspirin and proper treatment of the MPD is recommended in patients with SVT associated with the JAK2(V617F) mutation.

A unified definition of clinical resistance/intolerance to hydroxyurea in essential thrombocythemia: results of a consensus process by an international working group.

A widely accepted definition of resistance or intolerance to hydroxyurea (HU) in patients with essential thrombocythemia (ET) is lacking. An international working group (WG) was convened to develop a consensus formulation of clinically significant criteria for defining resistance/intolerance to HU in ET. To this aim, an analytic hierarchy process (AHP), a multiple-attribute decision-making technique, was used. The steps consisted of selecting the candidate criteria for defining resistance/intolerance; identifying the motivations that could influence the preference of the WG for any individual criterion; comparing the candidate criteria in a pair-wise manner; and grading them according their ability to fulfill the motivations. Every step in the model was derived by questionnaires or group discussion. The WG proposed that the definition of resistance/intolerance should require the fulfillment of at least one of the following criteria: platelet count greater than 600,000/micro l after 3 months of at least 2 g/day of HU (2.5 g/day in patients with a body weight over 80 kg); platelet count greater than 400,000/micro l and WBC less than 2500/micro l or Hb less than 10 g/dl at any dose of HU; presence of leg ulcers or other unacceptable muco-cutaneous manifestations at any dose of HU; HU-related fever.

Current diagnostic criteria for the chronic myeloproliferative disorders (MPD) essential thrombocythemia (ET), polycythemia vera (PV) and chronic idiopathic myelofibrosis (CIMF).

The clinical criteria for the diagnosis of essential thrombocythemia (ET) according to the polycythemia vera study group (PVSG) do not distinguish between ET and thrombocythemia associated with early stage PV and prefibrotic chronic idiopathic myelofibrosis (CIMF). The clinical criteria of the PVSG for the diagnosis of polycythemia vera (PV) only detects advanced stage of PV with increased red cell mass. The bone marrow criteria of the World Health Organization (WHO) are defined by pathologists to explicitly define the pathological criteria for the diagnostic differentiation of ET, PV, and prefibrotic and fibrotic CIMF. As the clinical PVSG and the pathological WHO criteria show significant shortcomings, an updated set of European Clinical and Pathological (ECP) criteria combined with currently available biological and molecular markers are proposed to much better distinct true ET from early PV mimicking ET, to distinguish ET from thrombocythemia associated with prefibrotic CIMF, and to define the various clinical and pathological stages of PV and CIMF that has important therapeutic and prognostic implications. Comparing the finding of clustered giant abnormal megakaryocytes in a representative bone marrow as a diagnostic clue to MPD, the sensitivity for the diagnosis of MPD associated with splanchnic vein thrombosis was 63% for increased red cell mass, 52% for low serum EPO level, 72% for EEC, and 74% for splenomegaly indicating the superiority of bone marrow histopathology to detect masked early and overt MPD in this setting. The majority of PV and about half of the ET patients have spontaneous EEC, low serum EPO levels and PRV-1 over-expression and are JAK2 V617F positive. The positive predictive value for the diagnosis of PV of spontaneous growth of endogenous erythroid colonies (EEC) of peripheral blood (PB) and bone marrow (BM) cells is about 80-85% when either PB or BM EEC assays, and up to 94% when BM and PB EEC assays were performed. The diagnostic impact of low serum EPO levels (ELISA assay) in a large study of 186 patients below the normal range (<3.3 IU/l) had a sensitivity specificity and positive predictive value of 87%, 97% and 97.8%, respectively, for the diagnosis of PV. There is a significant overlap of serum EPO levels in PV versus control and controls versus SE. The specificity of a JAK2 V617F PCR test for the diagnosis of MPD is high (near 100%), but only half of ET and MF (50%) and the majority of PV (up to 97%) are JAK2 V617F positive. The use of biological markers including JAK2 V617 PCR test, serum EPO, PRV-1, EEC, leukocyte alkaline phosphatase score and peripheral blood parameters combined with bone marrow histopathology has a high sensitivity and specificity (almost 100%) to diagnose the early and overt stages of ET, PV and CIMF in JAK2 V617F positive and negative MPDs.

[From gene to disease; primary erythermalgia--a neuropathic disease as a consequence of mutations in a sodium pump gene]. / Van gen naar ziekte; de neuropathische ziekte 'primaire erythermalgie' als gevolg van mutaties in een natriumpompgen.

Primary erythermalgia is a rare autosomal dominant inherited disorder characterized by recurrent attacks of red, warm and painful burning extremities. The gene involved in primary erythermalgia, SCN9A, encodes for a voltage dependent sodium channel alpha subunit (NaV1.7). NaV1.7 is located in dorsal root ganglions and in nociceptive peripheral neurons. It has been hypothesized that mutations lead to a gain of function and hyperexcitability of peripheral sensory neurons contributing to symptoms in primary erythermalgia.

Among inflammation and coagulation markers, PAI-1 is a true component of the metabolic syndrome.

OBJECTIVE: To investigate whether leukocyte count, fibrinogen, von Willebrand factor (vWF) and plasminogen activator inhibitor-1 activity (PAI-1) are increased in subjects with the metabolic syndrome as defined by the National Cholesterol Education Program-Adult Treatment Panel III (NCEP-ATPIII) and the World Health Organisation (WHO). DESIGN: Cross-sectional study. SUBJECTS: A total of 520 overweight and obese subjects: 379 women and 141 men, visiting the weight management clinic of a University Hospital. SUBJECTS AND MEASUREMENTS: Waist circumference, triglycerides, HDL cholesterol, blood pressure and fasting glucose were determined, and the presence or absence of the metabolic syndrome according to the NCEP-ATPIII criteria was assessed. In 349 subjects, data on the waist-to-hip ratio (WHR) and albumin excretion rate were available and the WHO criteria were applied. Insulin resistance was defined using the HOMA-IR index. RESULTS: Subjects with the metabolic syndrome according to the NCEP-ATPIII criteria had significantly higher levels of leukocyte count (P < 0.001) and PAI-1 (P < 0.001), while no significant differences were found for fibrinogen or vWF (P > 0.05). Using the WHO criteria, similar results were found except for vWF, where higher levels were found in subjects with the metabolic syndrome. When subjects were classified according to the number of components of the metabolic syndrome, levels of leukocyte count, vWF and PAI-1 activity were significantly different (P < 0.05). In logistic regression analysis PAI-1, gender and leukocyte count were independent determinants of the metabolic syndrome (P < 0.001). CONCLUSION: Evidence for being a true component of the metabolic syndrome is strong for PAI-1, less for leukocyte count and weak for vWF and fibrinogen.

Thrombophilia and venous thromboembolism. International consensus statement. Guidelines according to scientific evidence.

Thrombophilia is the term now used to describe predisposition to increased risk of venous and occasionally arterial thromboembolism due to hematological abnormalities. It can be a multifactorial disorder where congenital defects of anticoagulant or procoagulant factors may be combined with acquired hematological abnormalities. It should be considered in patients with a documented unexplained thrombotic episode or a positive family history. The aim of this document is to provide guidelines for investigation and management of patients with thrombophilia in the presence or absence of venous thromboembolism (VTE).

A critical appraisal of non-invasive diagnosis and exclusion of deep vein thrombosis and pulmonary embolism in outpatients with suspected deep vein thrombosis or pulmonary embolism: how many tests do we need?

The requirement for a safe diagnostic strategy should be based on an overall posttest incidence of venous thromboembolism of less than 1% during 3 month follow-up. Compression ultrasonography (CUS) has a negative predictive value (NPV) of 97% to 98% indicating the need of repeated CUS testing. Serial CUS testing is safe but you have to repeat 100 CUS to find 1 or 2 CUS positive for deep vein thrombosis (DVT), which is not cost-effective indicating the need to improve the diagnostic work-up of DVT by the use of clinical score assessment and D-dimer testing. The combination of a less sensitive D-dimer test (SimpliRed) and low clinical score does not, whereas the combination of a sensitive D-dimer test (ELISA VIDAS or Tinaquant) and low clinical score does safely exclude DVT without the need of CUS. The combination of a first negative CUS and a negative less sensitive D-dimer test (SimpliRed) or a sensitive ELISA D-dimer at a higher cut off level of 1,000 ng/ml safely excludes DVT with a NPV of > 99% without the need to repeated CUS in about 60%. The sequential use of a sensitive D-dimer and clinical score assessment will safely reduce the need for CUS testing by 40% to 60%. Large prospective outcome studies demonstrate that one negative examination with complete duplex color ultrasonography (CCUS) of the proximal and distal veins of the affected leg with suspected DVT is safe to withhold anticoagulant treatment with a NPV of 99.5%. This indicates that CCUS is equal or superior to serial CUS or the combined use of clinical score, D-dimer testing and CUS. Pulmonary angiography is the gold standard for segmental pulmonary embolism (PE) but not for subsegmental PE. A normal perfusion lung scan and a normal rapid ELISA VIDAS D-dimer test safely exclude PE. Helical spiral CT detects all clinically relevant PE and a large number of alternative diagnoses in symptomatic patients with a non-diagnostic ventilation perfusion scan (VP-scan) or a high probability VP-scan. Single-slice helical CT as the primary diagnostic test in patients with suspected PE in 5 retrospective studies and in 3 prospective management studies indicate that the NPV of a normal helical spiral CT, a negative CUS of the legs together with a low or intermediate pretest clinical probability is 99%. Helical spiral CT can replace both the VP-scan and pulmonary angiography to safely rule in and out PE. The combination of clinical assessment, a rapid ELISA VIDAS D-dimer followed by CUS will reduce the need for helical spiral CT by 40% to 50%.

Diagnosis of deep vein thrombosis: how many tests do we need?

The requirement for a safe diagnostic strategy should be based on an overall post-test incidence of venous thromboembolism (VTE) of less than 1% during 3 month follow-up. Compression ultrasonography (CUS) has a negative predictive value (NPV) of 97 to 98% indicating a post-CUS incidence of deep vein thrombosis (DVT) of 2 to 3%. A post-CUS DVT incidence of 3% implicates that 90 to 120 DVTs per 1 million inhabitants will be overlooked each year indicating the need to improve the diagnostic work-up of DVT as much as possible. The qualitative D-dimer test (SimpliRed) has a sensitivity of 82 to 89% and a negative predictive value of 94 to 95% indicating a 5 to 6% post-test incidence of DVT, which is not sensitive enough for venous thrombosis exclusion. The post-test DVT incidence could be reduced from 3.2% to 0.6% in one study and from 11% to 2% in another study by the combination of a normal CUS and low clinical score and from 4.5% to 1.6% by the combination of low clinical score and a negative SimpliRed test in one study. The combination of a negative CUS and a negative SimpliRed test reduced the post-test incidence of DVT from 2.6% to < 1% or even < 1% in two management studies without the need of a repeated CUS on the basis of which anticoagulant therapy can safely be withheld. The rapid quantitative turbidimetric D-dimer assay (Tinaquant) has a sensitivity and a negative predictive value (NPV) of 97.7% with a 2.3% post-test incidence of DVT. The combination of a normal Tinaquant D-Dimer test result plus a low to moderate clinical score reduces the post-test incidence of DVT from 2.3 to 0.6% without the need of CUS testing in 29% of patients with suspected DVT. The rapid ELISA VIDAS D-dimer assay has a sensitivity and NPV of 98.6 and 99.5% in two management studies for the exclusion of DVT irrespective of clinical score. The combination of a normal ELISA VIDAS D-Dimer test with clinical score assessment will reduce the post-test DVT incidence of less than 0.5% and the need for CUS testing by 40 to 50%. It is concluded that the sequential use of a rapid quantitative D-dimer test, clinical score and CUS appears to be safe and the most cost-effective diagnostic work-up of DVT.

Non-invasive diagnosis of pulmonary embolism, anno 2005.

Pulmonary angiography is the gold standard for segmental pulmonary embolism (PE) but no longer for subsegmental PE, because the inter-observer agreement for angiographically documented subsegmental PE is only 60%. Two non-invasive tools exclude PE with a negative predictive value of >99% : a normal perfusion lung scan and a normal rapid ELISA VIDAS D-dimer test. The positive predictive value is 85 to 88% for a high probability ventilation-perfusion lung scan (VP-scan) and >95% for helical spiral CT. The prevalence of PE in management studies of symptomatic patients with a non-diagnostic VP-scan is 20 to 24%. Helical spiral CT detects all clinically relevant PE and a large number of alternative diagnoses in symptomatic patients with a non-diagnostic VP-scan or a high probability VP-scan. Single-slice helical CT as the primary diagnostic test in patients with suspected PE in three retrospective studies and in two prospective management study indicate that the negative predictive value of a normal helical spiral CT, a negative compression ultrasonography of the legs (CUS) together with a low or intermediate pre-test clinical probability is >99%. Therefore, helical spiral CT can replace both the VP-scan and pulmonary angiography to safely rule in and out PE. The combination of clinical assessment, a rapid ELISA VIDAS D-dimer followed by CUS will reduce the need for helical spiral CT by 40 to 50%.

Platelet-mediated microvascular inflammation and thrombosis in thrombocythemia vera: a distinct aspirin-responsive arterial thrombophilia, which transforms into a bleeding diathesis at increasing platelet counts.

Erythromelalgia is the main, pathognomonic and presenting symptom in patients with essential thrombocythemia and thrombocythemia associated with polycythemia vera. Complete relief from erythromelalgic and acrocyanotic pain is obtained with the cyclooxygenase inhibitors aspirin and indomethacin, but not with sodiumsalicylate, dipyridamol, sulfinpyrozone and ticlopedine. Thus, cyclooxygenase metabolites are necessary for erythromelalgia to develop. Local platelet consumption in erythromelalgic areas became evident by the demonstration of arteriolar fibromuscular intimal proliferation and occlusions by platelet-rich thrombi in skin biopsies, by the findings of shortened platelet survival times, significant higher levels of platelet activation markers beta-thromboglobulin, thrombomoduline and increased urinary thromboxane B2 excretion in thrombocythemia patients suffering from erythromelalgia. Aspirin treatment of erythromelalgia in thrombocythemia patients resulted in the disappearance of the erythromelalgic, thrombotic signs and symptoms, correction of the shortened platelet survival times, and a significant reduction of the increased levels of beta-TG, PF4, TM and urinary TxB2 excretion to normal. Erythromelalgia is frequently preceded or followed by atypical transient neurologic, ocular or coronary ischemic symptoms, which specifically respond to low-dose aspirin or reduction of platelet counts to normal. The broad spectrum of acropareshesias, erythromelalgia and acrocyanotic ischemia together with the episodic and transient atypical TIAs and ocular or coronary ischemic symptoms are caused by spontaneous activation and aggregation of hypersensitive platelets in the end-arterial microvasculature involving the peripheral, cerebral and coronary circulation of thrombocythemia patients. These microvascular circulation ischemic disturbances in thrombocythemia vera already occur at platelet counts in excess of 400 x 10(9) l(-1). Low-dose aspirin is highly effective and safe in the cure and prevention of thrombotic and ischemic events and does not elicit bleedings at platelet counts below 1000 x 10(9) l(-1). Spontaneous hemorrhages usually occur at very high platelet counts far in excess of 1000 x 10(9) l(-1) (HT) due to an acquired von Willebrand factor deficiency at increasing platelet counts. At platelet counts between 1000 and 2000 x 10(9) l(-1), thrombosis and bleeding (ETT and HT) frequently occur in sequence or paradoxically and low-dose aspirin does prevent thrombotic complications but aggravates or may elicit bleeding symptoms. Reduction of the platelet count to below 1000 x 10(9) l(-1) by platelet lowering agents usually results in the disappearance of the bleeding tendency and improvement of the von Willebrand syndrome, but the thrombotic tendency persists as long as platelet counts are above the upper limit of normal.

Non-invasive exclusion and diagnosis of pulmonary embolism by sequential use of the rapid ELISA D-dimer assay, clinical score and spiral CT.

Pulmonary angiography is the gold standard for segmental pulmonary embolism (PE) but no longer for its subsegmental PE, because the inter-observer agreement for angiographically documented subsegmental PE is only 60%. Two non-invasive tools exclude PE with a negative predictive value of > 99%: a normal perfusion lung scan and a normal rapid ELISA VIDAS D-dimer test. The positive predictive value of a high probability ventilation-perfusion lung scan (VP-scan) is only 85% to 87%. The combination of a low clinical score and a non-diagnostic VP-scan safely exclude PE without the need of angiography. The prevalence of PE and that of an alternative diagnosis in symptomatic patients with a non-diagnostic VP-scan are 10% to 20% and 30% to 45%, respectively. Helical spiral computed tomography (CT) detects all clinically relevant PE and a large number of alternative diagnoses in symptomatic patients with a non-diagnostic or high probability VP-scan. The positive predictive value of the spiral CT is > 95%. Single-slice helical CT as the primary diagnostic test in patients with suspected PE in retrospective outcome studies and in prospective multicenter management studies indicate that the negative predictive value of a negative spiral CT preceded or followed by a negative compression ultrasonography (CUS) is > 99%. Therefore, a helical spiral CT can replace both the VP-scan and pulmonary angiography to safely rule in and out PE. A negative rapid ELISA VIDAS D-dimer test result will reduce the need for helical spiral CT by 25% to 35%.

Aspirin-responsive painful red, blue, black toe, or finger syndrome in polycythemia vera associated with thrombocythemia.

Five patients with red, purple blue, or black toes or fingers due to thrombocythemia associated with polycythemia vera (polycythemia and thrombocythemia vera) in four and essential thrombocythemia (thrombocythemia vera) in one are described. The microvascular erythromelalgic syndrome of thrombocythemia was overlooked and progressed to cold blue swollen and painful fingers or black toes in three patients with polycythemia and thrombocythemia vera due to arteriographically documented occlusions of digital or large peripheral arteries with no evidence of preexistent atherosclerotic vascular disease. Concomitant erythromelalgia of the hand palm could be confirmed by the histopathological findings of arteriolar thrombotic lesions in the reticular dermis in two patients with polycythemia and thrombocythemia vera. The increased hematocrit in the presented patients with polycythemia and thrombocythemia vera contributed to the progression of the microvascular syndrome of thrombocythemia to major occlusive ischemic events of the extremities. Standard therapy with oral anticoagulants and reduction of the hematocrit to normal by bloodletting did not affect the platelet-mediated microvascular erythromelalgic, ischemic symptoms in the patients with polycythemia vera because thrombocythemia vera persisted. Complete relief of pain and restoration of the ischemic acral circulation disturbances in patients with thrombocythemia vera or thrombocythemia associated with polycythemia vera in maintained remission by bloodletting could be obtained by long-term treatment with low-dose aspirin.

Bilateral adrenal swelling as a cause of chest, back, and upper abdominal pain in essential thrombocythemia and polycythemia vera is due to microvascular ischemic thrombosis rather than to hemorrhage.

Bilateral massive adrenal swelling (BAS) on computed tomography (CT) scan with no enhancement after injection of intravenous contrast media has been observed in two completely different clinical settings. On the one hand, BAS is the result of ischemic necrosis and subsequent hemorrhagic infarction in patients with sepsis and hypotension in critically ill situations. On the other hand, BAS is the result of microvascular thrombosis, ischemia, and secondary inflammatory swelling in the setting of thrombotic conditions such as antiphospholipid syndrome (APS), heparin-induced thrombocytopenia and thrombosis (HITT), and thrombocythemia. In this study we present evidence that the etiology of unilateral or BAS in reported cases of essential thrombocythemia (ET) and polycythemia vera (PV) is similar to the etiology of microvascular circulation disturbances in thrombocythemia caused by platelet-mediated inflammation and thrombosis in the peripheral, cerebral, and/or coronary endarterial microvascular circulation.

Comparison of antiplatelet effect of loading dose of clopidogrel versus abciximab during coronary intervention.

Randomized clinical trials have evidently shown that the addition of thienopyridines or abciximab to standard aspirin results in a significant reduction of ischaemic complications after coronary stent implantation. A head-to-head comparison of these antithrombotic drug regimens during coronary intervention is, however, lacking, and this was the main aim of the present study. Thirty-nine patients with angina pectoris who were scheduled for coronary stent implantation were assigned to either group 1 (160 mg aspirin + 500 mg ticlopidine post-stent), group 2 (160 mg aspirin + abciximab + 500 mg ticlopidine post-stent) or group 3 (160 mg aspirin + loading dose (375/450 mg) clopidogrel pre-stent and 75 mg clopidogrel post-stent). A loading dose of 450 mg clopidogrel was found to be more effective than the standard loading dose of 375 mg. Platelet aggregation induced by 4 micromol/l adenosine diphosphate (ADP) was assessed in samples collected before intervention and 10 min, 4 h and 20 h after intervention. Before intervention, a moderate antiplatelet effect because of aspirin intake was observed (ADP aggregation level, +/- 50%) in all study groups. After intervention, platelet aggregation tended to be enhanced in group 1 while it was strongly inhibited in the groups pre-treated with clopidogrel or abciximab: ADP induced an aggregation level early after intervention of 60 +/- 12% in group 1 (ticlopidine post-stenting) versus 30 +/- 10% in group 3 (loading dose clopidogrel) versus 3 +/- 6% in group 2 (abciximab). Abciximab achieved a more complete inhibition of aggregation than clopidogrel (P = 0.007). The overall complication rate was low with only one major bleeding and one death due to side-branch occlusion with re-infarction occurring, both in the abciximab group. Platelet aggregation during coronary intervention is strongly inhibited by both abciximab and by high loading dose of clopidogrel. Although abciximab showed a stronger antiplatelet effect than clopidogrel, it remains to be established whether this ex vivo superiority of abciximab also translates into an overall clinical benefit in patients with elective stent implantation.

Distal deep venous thrombosis in a hemophilia A patient with inhibitor and severe infectious disease, 18 days after recombinant activated factor VII transfusion.

We describe a 38 year old hemophilia A patient with a factor VIII inhibitor who was admitted to our Hematology Department in January 2001 with a seriously infected and bleeding perianal ulcer. To treat infection and bleeding the patient received broad spectrum antibiotics and recombinant activated factor VII (rFVIIa) (Novoseven(R)) for about 1 month (see detailed time of administration and dosing schedule of rFVIIa further in text). Eighteen days after his last rVIIa infusion the patient developed an ultrasound proven right calf vein thrombosis. In the whole period of admission, preceding the thrombotic event the patient biologically showed a picture of severe systemic inflammatory disease as indicated by persistent increased levels of D-dimer and fibrinogen (table). It is an interesting point of discussion whether the calf thrombosis was provoked as a consequence of rFVIIa infusion (with symptoms 18 days after the last infusion) or as a consequence of long-standing immobilization and severe inflammatory disease immobilization and severe infection are conditions well known for promoting venous thromboembolic disease.

Exclusion and diagnosis of deep vein thrombosis in outpatients by sequential noninvasive tools.

Phlebography is the reference gold standard for the diagnosis of deep vein thrombosis (DVT), but due to its invasive nature and associated side effects it has been replaced by compression ultrasonography (CUS). Patients suspected of DVT are subjected to leg vein CUS that actually confirms DVT in only 16 to 28% of outpatients in large prospective management studies. CUS has a high positive predictive value of more than 98% for proximal DVT but usually misses calf vein thrombosis. Its negative predictive value for proximal DVT is about 97-98%, on the basis of which repeated scanning at day 7 after a negative first CUS (serial CUS) in outpatients with a first suspicion of DVT is advocated. Serial ultrasonography is costly and can be simplified and improved by the addition of clinical score and D-dimer testing. The safe exclusion of DVT by a rapid sensitive D-dimer test in combination with clinical score and/or CUS requires a negative predictive value of >99%. The negative predictive value for DVT is determined by the sensitivity of the rapid ELISA D-dimer test and the prevalence of DVT in subgroups of outpatients suspected of the condition. The prevalence of DVT in outpatients with a low, moderate and high clinical score varies widely from 3-10%, 15-30% and >70%, respectively. The combination of a low clinical score (prevalence DVT 3-5%) and a negative rapid ELISA D-dimer alone test will have a very high negative predictive value of >99.9% to exclude DVT without the need of CUS testing. The combination of a negative CUS and a negative rapid ELISA D-dimer test safely excludes DVT in patients with suspected DVT irrespective of the clinical score. The combination of a negative CUS, a low clinical score and a positive ELISA D-dimer but <1000 ng/ml excludes DVT with a negative predictive value of >99% without the need to repeat CUS. Patients with a negative CUS, scan but a positive ELISA D-dimer, and a moderate or high clinical score are still at risk with a probability of DVT of 3-5% and 20-30%, respectively and are thus candidates for repeated ultrasound scanning. The rapid ELISA D-dimer first followed by risk-based no, single or repeated CUS will be the most cost-effective strategy.

Acquired von Willebrand syndromes: clinical features, aetiology, pathophysiology, classification and management.

Acquired von Willebrand syndrome (AVWS) associated with hypothyroidism is of type I, results from a decreased synthesis of factor VIII and von Willebrand factor (VWF), responds to desmopressin with normal half-life times for factor VIII and VWF parameters, and disappears after treatment with I-thyroxine. AVWS type I or III, which occurs in a minority of patients with Wilms' tumour in the complete absence of an inhibitor against VWF and no absorption of factor VIII or VWF onto nephroblastoma cells, responds to chemotherapy and/or tumour resection. Hyaluronic acid produced by nephroblastoma cells may be the causative factor in atypical AVWS in Wilms' tumour. AVWS associated with thrombocythaemia of various myeloproliferative disorders is characterized by normal factor VIII and von Willebrand factor antigen (VWF: Ag) levels and a selective deficiency of functional ristocetin co-factor activity (VWF: RCo) and collagen-binding activity (VWF: CBA). AVWS type II in thrombocythaemia is caused by a platelet-dependent proteolysis of large VWF multimers, given the inverse relationship between platelet count and large VWF multimers in plasma and specific increases in the number of proteolytic VWF fragments in plasma. The laboratory findings of AVWS associated with systemic lupus erythematosus or IgG benign monoclonal gammopathy are characterized by a prolonged bleeding time and activated partial thromboplastin time, decreased or absent ristocetin-induced platelet activity, low to very low levels of factor VIII coagulant activity (mean 15%), VWF: Ag (mean 10.7%) and VWF: RCo (mean 6.2%), and a type II multimeric pattern of VWF. Neutralizing and non-neutralizing anti-VWF autoantibodies, usually IgG, have been detected in patient plasma either free or tightly bound to the intermediate and high molecular weight VWF factor VIII particles. The bound auto antibody-antigen complex is rapidly cleared from the circulation, resulting in low levels of factor VIII, VWF parameters as documented by a poor response to desmopressin and VWF factor VIII concentrate. High-dose intravenous immunoglobulin transiently corrects the factor VIII coagulant and VWF levels, lasting for a few weeks in AVWS type II associated with systemic lupus erythematosus or IgG benign monoclonal gammopathy. Prednisolone is effective in AVWS associated with autoimmune disorder. Prednisolone and chemotherapy will not affect AVWS associated with IgG benign monoclonal gammopathy because the monoclonal IgG protein remains to act as an anti-VWF autoantibody. An absorption of VWF to malignant cells has been documented in a few patients with various lymphoproliferative disorders or adrenal carcinoma and suggested to result in a depletion of VWF. The clinical picture of AVWS associated with early-stage IgG multiple myeloma, chronic lymphocytic leukaemia or non-Hodgkin's lymphoma without a paraprotein or no detectable underlying disorder is similar to that of AVWS type II in IgG benign monoclonal gammopathy but poorly documented with regard to the underlying immune mechanism of AVWS. The mechanical destruction of large VWF multimers may be of relevance in conditions in which the shear rate of flowing blood is increased, as may occur in cases of aortic stenosis, other heart valve defects or stenosed vessels. Drug-induced AVWS has been described in association with the use of pesticides valproic acid, ciprofloxacin, griseofulvin, tetracycline, thrombolytic agents and hydroxyethyl starch.