Alessandra Malato

Residual vein thrombosis to establish duration of anticoagulation after a first episode of deep vein thrombosis : the Duration of Anticoagulation based on Compression UltraSonography (DACUS) study

Residual vein thrombosis (RVT) indicates a prothrombotic state and is useful for evaluating the optimal duration of oral anticoagulant treatment (OAT). Patients with a first episode of deep vein thrombosis, treated with OAT for 3 months, were managed according to RVT findings. Those with RVT were randomized to either stop or continue anticoagulants for 9 additional months, whereas in those without RVT, OAT was stopped. Outcomes were recurrent venous thromboembolism and/or major bleeding. Residual thrombosis was detected in 180 (69.8%) of 258 patients; recurrent events occurred in 27.2% of those who discontinued (25/92; 15.2% person-years) and 19.3% of those who continued OAT (17/88; 10.1% person-years). The relative adjusted hazard ratio (HR) was 1.58 (95% confidence interval [CI], 0.85-2.93; P = .145). Of the 78 (30.2%) patients without RVT, only 1 (1.3%; 0.63% person-years) had a recurrence. The adjusted HR of patients with RVT versus those without was 24.9 (95% CI, 3.4-183.6; P = .002). One major bleeding event (1.1%; 0.53% person-years) occurred in patients who stopped and 2 occurred (2.3%; 1.1% person-years) in those who continued OAT. Absence of RVT identifies a group of patients at very low risk for recurrent thrombosis who can safely stop OAT. This trial was registered at http://www.ClinicalTrials.gov as no. NCT00438230.

Diagnosis and treatment of disseminated intravascular coagulation: Guidelines of the Italian Society for Haemostasis and Thrombosis (SISET)☆

BACKGROUND The diagnosis and treatment of disseminated intravascular coagulation (DIC) remain extremely controversial. PURPOSE The Italian Society for Thrombosis and Haemostasis commissioned a project to develop clinical practice guidelines for the diagnosis and treatment of DIC. METHODS Key questions about the diagnosis and treatment of DIC were formulated by a multidisciplinary working group consisting of experts in clinical medicine and research. After a systematic review and discussion of the literature, recommendations were formulated and graded according to the supporting evidence. In the absence of evidence, evidence of low quality, or contradictory evidence, a formal consensus method was used to issue clinical recommendations. RESULTS AND CONCLUSIONS In suspected DIC, we suggest the use of the diagnostic scores ISTH (grade C), JMHW (grade C) or JAAM (grade D) over stand alone tests. The cornerstone of the management of DIC remains the treatment of the underlying triggering disease. We do not suggest the use of antithrombin (grade D), dermatan sulphate (grade D), gabexate (grade D), recombinant factor VIIa (grade D), activated protein C (grade D), thrombomodulin (grade B). The use of unfractionated heparin or low-molecular-weight heparin is not suggested except for thromboembombolic prophylaxis in patients a high risk who do not have active bleeding (grade D). In patients with severe sepsis/septic shock and DIC we suggest the use of human recombinant activated protein C (grade D). In patients with DIC and active bleeding we suggest the use of transfusion therapy (platelets, plasma, cryoprecipitate) (grade D).

Long-term Clinical Outcomes of Splanchnic Vein Thrombosis: Results of an International Registry

IMPORTANCE Little information is available on the long-term clinical outcome of patients with splanchnic vein thrombosis (SVT). OBJECTIVE To assess the incidence rates of bleeding, thrombotic events, and mortality in a large international cohort of patients with SVT. DESIGN, SETTING, AND PARTICIPANTS A prospective cohort study was conducted beginning May 2, 2008, and completed January 30, 2014, at hospital-based centers specialized in the management of thromboembolic disorders; a 2-year follow-up period was completed January 30, 2014, and data analysis was conducted from July 1, 2014, to February 28, 2015. Participants included 604 consecutive patients with objectively diagnosed SVT; there were no exclusion critieria. Information was gathered on baseline characteristics, risk factors, and antithrombotic treatment. Clinical outcomes during the follow-up period were documented and reviewed by a central adjudication committee. MAIN OUTCOMES AND MEASURES Major bleeding, defined according to the International Society on Thrombosis and Hemostasis; bleeding requiring hospitalization; thrombotic events, including venous and arterial thrombosis; and all-cause mortality. RESULTS Of the 604 patients (median age, 54 years; 62.6% males), 21 (3.5%) did not complete follow-up. The most common risk factors for SVT were liver cirrhosis (167 of 600 patients [27.8%]) and solid cancer (136 of 600 [22.7%]); the most common sites of thrombosis were the portal vein (465 of 604 [77.0%]) and the mesenteric veins (266 of 604 [44.0%]). Anticoagulation was administered to 465 patients in the entire cohort (77.0%) with a mean duration of 13.9 months; 175 of the anticoagulant group (37.6%) received parenteral treatment only, and 290 patients (62.4%) were receiving vitamin K antagonists. The incidence rates (reported with 95% CIs) were 3.8 per 100 patient-years (2.7-5.2) for major bleeding, 7.3 per 100 patient-years (5.8-9.3) for thrombotic events, and 10.3 per 100 patient-years (8.5-12.5) for all-cause mortality. During anticoagulant treatment, these rates were 3.9 per 100 patient-years (2.6-6.0) for major bleeding and 5.6 per 100 patient-years (3.9-8.0) for thrombotic events. After treatment discontinuation, rates were 1.0 per 100 patient-years (0.3-4.2) and 10.5 per 100 patient-years (6.8-16.3), respectively. The highest rates of major bleeding and thrombotic events during the whole study period were observed in patients with cirrhosis (10.0 per 100 patient-years [6.6-15.1] and 11.3 per 100 patient-years [7.7-16.8], respectively); the lowest rates were in patients with SVT secondary to transient risk factors (0.5 per 100 patient-years [0.1-3.7] and 3.2 per 100 patient-years [1.4-7.0], respectively). CONCLUSIONS AND RELEVANCE Most patients with SVT have a substantial long-term risk of thrombotic events. In patients with cirrhosis, this risk must be balanced against a similarly high risk of major bleeding. Anticoagulant treatment appears to be safe and effective in most patients with SVT.

Natural history of mesenteric venous thrombosis in patients treated with vitamin K antagonists - A multi-centre, retrospective cohort study

Knowledge on the natural history of mesenteric vein thrombosis (MVT) and of the efficacy and safety of long-term oral anticoagulant therapy (OAT) in this setting is based on small uncontrolled series of patients with a limited follow-up. It was the aim of the study to assess the natural history of MVT in a cohort of patients treated with OAT. The charts of all MVT patients currently attending or who have attended four anticoagulation clinics were reviewed. Information on risk factors, treatment, recurrence, major bleeding and mortality was collected. Seventy-seven patients (mean age 49.2 years; 45 males) were included with a median follow-up of 36 months (range 2-204 months). Forty-six patients were treated with long-term OAT. Seven patients had venous thromboembolism (VTE) recurrence (5 splanchnic vein thromboses and two pulmonary emboli) for an incidence rate of 23.4 events /1,000 year patients. In two patients recurrent VTE occurred during OAT, for an incidence rate of 10.5 events /1,000 year patient. Five patients had VTE recurrence when OAT was suspened for an incidence rate of 45.9 events /1,000 year patient. Two patients (2.6%) had a major bleeding event. 97.3% of patients were alive at one year, and seven patients (9.1%) died during follow up. In conclusion, patients with MTV seem to have a low risk of recurrent VTE while receiving OAT. This risk appears increased after treatment is stopped.

Patients requiring interruption of long-term oral anticoagulant therapy: the use of fixed sub-therapeutic doses of low-molecular-weight heparin.

Summary.  Introduction: We tested the efficacy and safety of fixed doses of low‐molecular‐weight heparin (LMWH) in patients requiring interruption of vitamin‐K antagonist (VKA) because of invasive procedures. Methodology: Preoperatively, patients discontinued VKA for 5 ± 1 days; in those at low risk for thrombosis, LMWH was given at a prophylactic dosage of 3800 UI (nadroparin) or 4000 UI (enoxaparin) anti‐factor (F) Xa once daily the night before the procedure. In patients at high risk for thrombosis, LMWH was started early after VKA cessation and given at fixed sub‐therapeutic doses (3800 or 4000 UI anti‐FXa twice daily) until surgery. Postoperatively, LMWH was reinitiated 12 h after procedure while VKA was reinitiated the day after. Heparin was continued until a therapeutic INR value was reached. The primary efficacy endpoints were the incidence of thromboembolism and major bleeding from VKA suspension (because of surgery) up to 30 ± 2 days postprocedure. Results: A total of 328 patients (55.4% at low risk and 44.6% at high risk for thrombosis) were enrolled; 103 (31.4%) underwent major surgery and 225 (68.6%) non‐major invasive procedures. Overall, thromboembolic events occurred in six patients (1.8%, 95% confidence interval 0.4–3.2), five belonging to the high‐risk group and one belonging to the low‐risk group. Overall, major bleeding occurred in seven patients (2.1%, 95 confidence interval 0.6–3.6), six patients belonged to the high‐risk group and one belonged to the low‐risk group; most of the events occurred in the high‐risk group during major surgery. Conclusion: LMWH given at fixed sub‐therapeutic doses appears to be a feasible and safe approach for bridging therapy in chronic anticoagulated patients.

Relapsing or refractory idiopathic thrombotic thrombocytopenic purpura-hemolytic uremic syndrome: the role of rituximab

Idiopathic thrombotic thrombocytopenic purpura–hemolytic uremic syndrome (TTP‐HUS) is a rare disease responsive to treatment with plasma exchange (PE) but with a high percentage of relapse or refractory patients. A severe deficiency of ADAMTS‐13 (<5% of normal activity), congenital or caused by an autoantibody, may be specific for TTP and it has been proposed that severe ADAMTS‐13 deficiency now defines TTP. B cells play a key role in both the development and the perpetuation of autoimmunity, suggesting that B‐cell depletion could be a valuable treatment approach for patients with idiopathic TTP‐HUS. This review of the literature focuses on the role of rituximab, a chimeric monoclonal antibody directed against CD20 antigen expressed by B lymphocytes, in patients with relapsing or refractory TTP‐HUS with or without ADAMTS‐13 deficiency, suggesting that rituximab may produce clinical remission in a significant proportion of patients. Rituximab therapy reduces plasma requirement and avoids complications related to salvage‐immunosuppressive therapy. In conclusion, rituximab provides an effective, well‐tolerated, and safe treatment option for patients with idiopathic TTP‐HUS, thus giving an alternative approach to the current treatment based on PE.

Optimal Duration of Low Molecular Weight Heparin for the Treatment of Cancer-Related Deep Vein Thrombosis: The Cancer-DACUS Study

PURPOSE We evaluated the role of residual vein thrombosis (RVT) to assess the optimal duration of anticoagulants in patients with cancer who have deep vein thrombosis (DVT) of the lower limbs. PATIENTS AND METHODS Patients with active cancer and a first episode of DVT treated with low molecular weight heparin (LMWH) for 6 months were eligible. Patients were managed according to RVT findings: those with RVT were randomly assigned to continue LMWH for an additional 6 months (group A1) or to discontinue it (group A2), and patients without RVT stopped LMWH (group B). The primary end point was recurrent venous thromboembolism (VTE) during the 1 year after disconinuation of LMWH, and the secondary end point was major bleeding. Analyses are from the time of random assignment. RESULTS Between October 2005 and April 2010, 347 patients were enrolled. RVT was detected in 242 patients (69.7%); recurrence occurred in 22 of the 119 patients in group A1compared with 27 of 123 patients in group A2. The adjusted hazard ratio (HR) for group A2 versus A1 was 1.37 (95% CI, 0.7 to 2.5; P = .311). Three of the 105 patients in group B developed recurrent VTE; adjusted HR for group A1 versus B was 6.0 (95% CI, 1.7 to 21.2; P = .005). Three major bleeding events occurred in group A1, and two events each occurred in groups A2 and B. The HR for major bleeding in group A1 versus group A2 was 3.78 (95% CI, 0.77 to 18.58; P = .102). Overall, 42 patients (12.1%) died during follow-up as a result of cancer progression. CONCLUSION In patients with cancer with a first DVT, treated for 6 months with LMWH, absence of RVT identifies a population at low risk for recurrent thrombotic events. Continuation of LMWH in patients with RVT up to 1 year did not reduce recurrent VTE.

Residual vein thrombosis for assessing duration of anticoagulation after unprovoked deep vein thrombosis of the lower limbs: The extended DACUS study

The safest duration of anticoagulation after idiopathic deep vein thrombosis (DVT) is unknown. We conducted a prospective study to assess the optimal duration of vitamin K antagonist (VKA) therapy considering the risk of recurrence of thrombosis according to residual vein thrombosis (RVT). Patients with a first unprovoked DVT were evaluated for the presence of RVT after 3 months of VKA administration; those without RVT suspended VKA, while those with RVT continued oral anticoagulation for up to 2 years. Recurrent thrombosis and/or bleeding events were recorded during treatment (RVT group) and 1 year after VKA withdrawal (both groups). Among 409 patients evaluated for unprovoked DVT, 33.2% (136 of 409 patients) did not have RVT and VKA was stopped. The remaining 273 (66.8%) patients with RVT received anticoagulants for an additional 21 months; during this period of treatment, recurrent venous thromboembolism and major bleeding occurred in 4.7% and 1.1% of patients, respectively. After VKA suspension, the rates of recurrent thrombotic events were 1.4% and 10.4% in the no‐RVT and RVT groups, respectively (relative risk = 7.4; 95% confidence interval = 4.9–9.9). These results indicate that in patients without RVT, a short period of treatment with a VKA is sufficient; in those with persistent RVT, treatment extended to 2 years substantially reduces, but does not eliminate, the risk of recurrent thrombosis. Am. J. Hematol. 2011.

Rituximab for managing relapsing or refractory patients with idiopathic thrombotic thrombocytopenic purpura--haemolytic uraemic syndrome.

Thrombotic thrombocytopenic purpura (TTP) is a rare disorder characterized by thrombocytopenia, microangiopathic haemolytic anaemia, neurological and renal abnormalities and fever1, with a mortality rate, in the absence of treatment, of almost 90%. Since such criteria do not distinguish TTP from haemolytic uraemic syndrome (HUS), the comprehensive term TTP-HUS is more approriate2. The standard therapy is urgent plasma exchange (PE)1, which reduces mortality to 10% or less3–9. Because of its dramatic effect on short and long-term outcome, it is now accepted that PE can be begun, in the absence of an alternative diagnosis, even when not all of the above criteria are fulfilled3,4,6,9,10. The evident advantage of early initiation of therapy along with the decreased diagnostic threshold has resulted in a 7-fold increase of patients treated with PE for TTP-HUS from 1981 to 199711. The symptoms of TTP are related to the presence of von Willebrand factor (VWF)-rich platelet thrombi in arterioles and capillaries. VWF is a multimeric plasma glycoprotein crucial for both platelet adhesion and aggregation, especially at the high shear rates present in the microvasculature. The size of VWF multimers is physiologically regulated in vivo by a specific metalloprotease, ADAMTS-13 (a disintegrin-like and metalloprotease with thrombospondin type 1 repeats)12. A severe deficiency of ADAMTS-13 (< 5% of normal activity) may be specific for TTP13 and it has been proposed that severe ADAMTS-13 deficiency now defines TTP14,15. Because ADAMTS-13 deficiency, whether idiopathic or caused by an autoantibody, provides a possible explanation for the effectiveness of PE (removal of the autoantibody by apheresis; supply of ADAMTS-13 by plasma replacement), it has been suggested that the levels of this metalloprotease can be used to guide treatment decisions14,16–19. At present it is not possible to establish the sensitivity of ADAMTS-13 deficiency for identifying patients who may respond to PE. In seven reports, 45% to 100% of patients with TTP were reported to have severe deficiency of ADAMTS-13 activity19–25 while such a high rate has not been described in those with HUS19,20,23. However, the interpretation of these studies is limited by the absence of explicit criteria for distinguishing patients with TTP from patients with HUS. PE has been proven effective even in patients without deficiency of ADAMTS-13 activity, which makes it difficult to understand how PE is benificial2. In conclusion, the role of ADAMTS-13 activity in the diagnosis and treatment decisions in patients with TTP or HUS remains unknown. Therapy with PE should be implemented in all patients with TTP-HUS and continued until the resolution of signs and/or symptoms and normalisation of laboratory tests; this can require long-term therapy. PE has some other disadvantages: first of all, it is not a risk-free procedure since a substantial number of major complications have been reported26,27. Furthermore, about 10% to 20% of TTP-HUS patients do not respond or have only an incomplete response2. Various different types of immunosuppressive treatment have been proposed for refractory patients14,29,30,32, including steroids and immunosuppressive or immune-modulating agents; however, the lack of robust data does not allow proper suggestion of such agents in the setting of acute refractory or chronic relapsing TTP28,32. Splenectomy has been proposed for patients with refractory or relapsing TTP, with reported remission rates of 50–100%29, but relapses have occurred in a considerable proportion of patients, most of them with severe ADAMTS-13 deficiency2,29,33,35. It has recently been shown that splenectomy can cause the disappearance of antibodies, normalisation of ADAMTS-13 activity and clinical remission in cases of refractory/relapsing TTP associated with anti-ADAMTS-13 autoantibodies. Other authors reported a low frequency of relapses in a large cohort of patients who underwent splenectomy30. Rituximab, a chimaeric monoclonal antibody directed against the CD20 antigen present on B lymphocytes, is used in lymphoma patients and those with rheumatoid arthritis33. Its action relies on clearance of the B lymphocytes responsible for antibody production by complement-dependent cytotoxicity, antibody-dependent cellular cytotoxicity or directly by inducing apoptosis31,33. The understanding that ADAMTS-13 deficiency could be antibody-mediated first provided the rationale for the use of rituximab in TTP-HUS12, but its reported effectiveness even in TTP-HUS patients without antibody-mediated ADAMTS-13 deficiency as well as in cases of refractory/relapsing cases makes this monoclonal antibody a very attractive therapeutic agent33–35. The data suggest that the drug may not simply decrease ADAMTS-13 autoantibody production by depleting B cells, but that it may have additional mechanisms of action. Kameda et al.34 suggested that B-cell depletion by rituximab reduces excessive cytokine production in patients with secondary TTP, thus containing the level of VWF multimers within the normal range. At present, only data from case series have been published and many questions remain open regarding the target population, timing of initiation, duration of treatment and concomitant PE34–49. Here we describe four patients with refractory/relapsing idiopathic TTP-HUS who were successfully treated with rituximab (Table I). Table I Patients’ characteristics

Incidence of thromboembolic complications in patients with mechanical heart valves with a subtherapeutic international normalized ratio

OBJECTIVE Subtherapeutic international normalized ratios are frequently encountered in clinical practice, and patients with mechanical heart valves with inadequate anticoagulation may be exposed to an increased risk of thromboembolic events. There are no data on thromboembolic event risk for these patients. METHODS We assessed the current practice patterns in the management of patients with mechanical heart valves with subtherapeutic international normalized ratios and assessed the risk of thromboembolic complications in this setting. The charts of patients with mechanical heart valves followed up in two anticoagulation clinics were reviewed. Patients with a history of stable, therapeutic anticoagulation but with a subtherapeutic international normalized ratio were included. Patients who underwent invasive procedures requiring temporary suspension of antithrombotic therapy were excluded. Data on use and dose of low-molecular weight heparin bridging therapy were collected. RESULTS The incidence of objectively confirmed thromboembolic events within 90 days after obtaining the index international normalized ratio was assessed. Two hundred ninety-four patients with mechanical heart valves were included (mean age 63.3 years, 47.3% male). Low-molecular weight heparin was prescribed in 14 cases (4.8%). At 90 days, 1 patient had a thromboembolic complication (0.3%, 95% confidence interval 0%-1.9%). CONCLUSION Patients with previously stable, therapeutic anticoagulation with a subtherapeutic international normalized ratio have a low risk of thromboembolic events. Withholding low-molecular weight heparin bridging therapy is a reasonable therapeutic option in these cases.