Sophie Testa

Clinical course of high‐risk patients diagnosed with antiphospholipid syndrome

See also Galli M. The antiphospholipid triangle. This issue, pp 234–6.

Incidence of a first thromboembolic event in asymptomatic carriers of high-risk antiphospholipid antibody profile: a multicenter prospective study

Persistent antiphospholipid (aPL) antibodies are occasionally found in subjects without prior history of thromboembolic events (TEs), raising the dilemma of whether to initiate or not a primary thromboprophylaxis. A first TE is considered rare in aPL carriers, but previous studies did not consider the aPL profile nor was the test positivity confirmed in a reference laboratory. In this study, 104 subjects with high-risk aPL profile (positive lupus anticoagulant, anticardiolipin, and anti-β(2)-glycoprotein I antibodies, triple positivity) confirmed in a reference laboratory, were followed up for a mean of 4.5 years. There were 25 first TEs (5.3% per year): the cumulative incidence after 10 years was 37.1% (95% confidence interval [CI], 19.9%-54.3%). On multivariate analysis, male sex (hazard ratio = 4.4; 95% CI, 1.5-13.1, P = .007) and risk factors for venous thromboembolism (hazard ratio = 3.3; 95% CI, 1.3-8.5, P = .01) were independent predictors for TEs. Aspirin did not significantly affect the incidence of TE. In conclusion, the occurrence of a first TE in carriers of high-risk aPL profile is considerable; it is more frequent among male subjects and in the presence of additional risk factors for venous TE. These data can help in the decision to initiate primary thromboprophylaxis in these subjects.

Questions and answers on the use of dabigatran and perpectives on the use of other new oral anticoagulants in patients with atrial fibrillation: A consensus document of the Italian Federation of Thrombosis Centers (FCSA)

Dabigatran and other new oral anticoagulants (OAC) represent a step forward in stroke prevention in patients with atrial fibrillation (AF). They indeed have been shown to be an alternative to vitamin K antagonists (VKAs) without the burden of laboratory control. However, these new drugs compete with an effective and well-established therapy, thus bringing about a series of questions and doubts. In this report members of the board of the Italian Federation of Thrombosis Centers (FCSA) answer some questions every clinician might be confronted with.

Standardized Low–Molecular-Weight Heparin Bridging Regimen in Outpatients on Oral Anticoagulants Undergoing Invasive Procedure or Surgery An Inception Cohort Management Study

Background— Bridging therapy with low–molecular-weight heparin is usually recommended in patients who must stop oral anticoagulants before surgical or invasive procedures. To date, there is no universally accepted bridging regimen tailored to the patient’s thromboembolic risk. This prospective inception cohort management study was designed to assess the efficacy and safety of an individualized bridging protocol applied to outpatients. Methods and Results— Oral anticoagulants were stopped 5 days before the procedure. Low–molecular-weight heparin was started 3 to 4 days before surgery and continued for 6 days after surgery at 70 anti–factor Xa U/kg twice daily in high-thromboembolic-risk patients and prophylactic once-daily doses in moderate- to low-risk patients. Oral anticoagulation was resumed the day after the procedure with a boost dose of 50% for 2 days and maintenance doses afterward. The patients were followed up for 30 days. Of the 1262 patients included in the study (only 15% had mechanical valves), 295 (23.4%) were high-thromboembolic-risk patients and 967 (76.6%) were moderate- to low-risk patients. In the intention-to-treat analysis, there were 5 thromboembolic events (0.4%; 95% confidence interval, 0.1 to 0.9), all in high-thromboembolic-risk patients. There were 15 major (1.2%; 95% confidence interval, 0.7 to 2.0) and 53 minor (4.2%; 95% confidence interval, 3.2 to 5.5) bleeding episodes. Major bleeding was associated with twice-daily low–molecular-weight heparin administration (high-risk patients) but not with the bleeding risk of the procedure. Conclusions— This management bridging protocol, tailored to patients’ thromboembolic risk, appears to be feasible, effective, and safe for many patients, but safety in patients with mechanical prosthetic valves has not been conclusively established.

Usefulness of repeated D-dimer testing after stopping anticoagulation for a first episode of unprovoked venous thromboembolism: the PROLONG II prospective study

The PROLONG randomized trial showed that a normal D-dimer (D-d) 1 month after anticoagulation suspension for unprovoked venous thromboembolism (VTE) was associated with a low risk of late recurrences (4.4% patient years). However, it is unknown whether D-d changes subsequently. The aim of this prospective multicenter study was to assess D-d time course and its relation with late recurrences in patients with normal D-d 1 month after anticoagulation suspension for a first episode of unprovoked VTE. D-d was measured with a qualitative method (Clearview Simplify D-dimer; Inverness Medical Professional Diagnostics). Patients with a normal D-d 1 month after stopping anticoagulation repeated D-d testing every 2 months for 1 year. D-d was normal in 68% (243/355) of patients 1 month after anticoagulation suspension. Patients in whom D-d became abnormal at the third month and remained abnormal afterward had a higher risk of recurrence (7/31; 27% patient years; 95% confidence interval [CI]: 12-48) than patients in whom D-d remained normal at the third month and afterward (4/149; 2.9% patient years; 95% CI: 1-7; adjusted hazard ratio: 7.9; 95% CI: 2.1-30; P = .002). Repeated D-d testing after anticoagulation suspension for a first episode of unprovoked VTE could help tailor the duration of treatment. This trial is registered at http://clinicaltrials.gov as NCT00266045.

Prevention and treatment of bleeding complications in patients receiving vitamin K antagonists, Part 1: Prevention

Oral anticoagulant therapy with coumarins is widelyused for the prevention and treatment of venous andarterial thrombosis. The most common complication ofvitamin K antagonist therapy is bleeding, with majorbleeding events occurring in 1–3% of patients annually.Although a number of potential predictors for bleedinghave been described, little research is available to pro-vide evidence-based guidelines for the prevention ofbleeding. To address this knowledge gap, we assembleda panel of international experts and posed a series offocused clinical questions. The experts were asked toperform a systematic literature review and summarize theresults of that review within the context of their clinicalquestion. In many cases, data were lacking and theexperts were asked to supplement their answer with clin-ical expertise. To minimize bias the reviews were vettedby three internationally recognized scholarly bodies. Ourgoal in this project is to provide ‘‘best evidence’’ forclinicians faced with the problem of minimizing the riskof bleeding in patients on vitamin K antagonist therapy.The number of patients receiving vitamin K antagonisttherapy increases annually and probably exceeds three mil-lion in the United States. Despite monitoring and carefuldose adjustment, the time spent in the therapeutic Interna-tional Normalized Ratio (INR) range varies from below 47%to a maximum of 81% of the time [1]. Major bleedingevents occur in up to 3% of ‘‘standard risk’’ patients treatedwith an oral vitamin K antagonist in one year. Despite thehigh frequency of use of vitamin K antagonists, very littleresearch has been performed examining techniques toreduce the risk of bleeding. In particular, the role of clinicalbleeding prediction rules is uncertain and further study ofthe role of drug and food interactions, the impact of patienteducation, the risk to benefit ratio of combining differentantithrombotic drugs, the role of pharmacogenomic testing,and on the optimal management of patients presentingwith elevated INR values is required. However, despitethese needs clinicians are still required to initiate andmonitor vitamin K antagonists while mitigating the risks ofbleeding and thrombosis. This article provides recommen-dations designed to assist clinicians in estimating andmanaging bleeding risk in patients receiving oral vitamin Kantagonists.Clinical questions were formulated by three of theauthors (WA, MC, DG) and authors were selected basedon their published experience. In each case, a North Ameri-can and Italian expert were asked to co-author theresponse to the question. The authors were asked to per-form a comprehensive literature review and make specificrecommendations on the basis of this review in concertwith their clinical experience. Given the anticipated lack ofevidence, the recommendations are largely opinion-based.To increase the rigor of the recommendations, each sectionwas carefully reviewed by members of the Italian Societyfor Studies on Haemostasis and Thrombosis, the Federa-tion of Centers for the Diagnosis of Thrombosis and Sur-veillance of Antithrombotic Therapies, and the Anticoagula-tion Forum.To provide readers with information on the strength of therecommendations, we have asked the authors to use theAmerican College of Chest Physicians GRADE system toevaluate the quality of the recommendations [2]. In thissystem, grades of 1A, 1B, 1C, 2A, 2B, and 2C are possible.A 1A recommendation is a strong recommendation basedon evidence from randomized trials or exceptional qualityobservational data which is thought to apply to mostpatients, in most circumstances. A 2C recommendation is avery weak recommendation, based on poor quality evi-dence, and for which there is doubt as to which patientsthe recommendation applies. Our goal with this project is toboth provide guidance to clinicians and to stimulate addi-tional research designed to improve the quality of evidenceon which treatments for vitamin K antagonist associatedbleeding are based.Clinical Scenario 1A 79-year-old woman with atrial fibrillation and well-con-trolled hypertension is assessed for anticoagulant therapy.She has no history of diabetes, congestive heart failure,stroke, or transient ischemic attack (TIA). Two years agoshe had an upper gastrointestinal bleed treated with a pro-

Survey of lupus anticoagulant diagnosis by central evaluation of positive plasma samples.

Summary.  Objective: To determine whether the diagnosis of lupus anticoagulant (LAC) in a large cohort of positive patients was confirmed at a reference laboratory. Methods: Over a 1‐year period, each participating center collected samples from LAC‐positive patients. Plasma was filtered and kept deep‐frozen until it was sent on dry ice to the reference laboratory by express courier. Centers returned detailed laboratory information and clinical data from each patient. The reference laboratory screened plasma samples by diluted Russell viper venom time (dRVVT) and kaolin clotting time (KCT). When these were prolonged, 1:1 mixing studies were carried out, and confirmatory tests were performed as appropriate. Positive samples were further tested by thrombin time (TT). The presence of heparin was checked by measuring antifactor Xa activity when TT was prolonged. Negative samples were tested by activated partial thromboplastin time using hexagonal phospholipids. Results: Plasma samples from 302 patients from 29 anticoagulation clinics were analyzed. LAC was excluded in 71 samples (24%), because dRVVT and KCT screening test results were normal (34) or reversed to normal by mixing studies (35). The remaining two samples were considered negative because they contained heparin. LAC‐negative patients showed different characteristics from those in whom diagnosis was confirmed. They were significantly older (49.7 vs. 45.0 years, P < 0.03), were more often first diagnosed (66% vs. 41%, P < 0.001), and were more frequently judged as mild in LAC potency (60% vs. 25%, P < 0.0001). Moreover, anticardiolipin and anti‐β2‐glycoprotein I antibody values were more often normal in LAC‐negative (82%) than in LAC‐positive (42%) samples (P < 0.0001). LAC‐positive samples identified by both dRVVT and KCT (146/231, 63%) showed a LAC potency that was significantly stronger than that in samples in which LAC diagnosis was made by a single test. Conclusions: A false‐positive LAC diagnosis is not uncommon across specialized centers. Patients’ characteristics and a complete antiphospholipid antibody profile may help to identify these individuals.

Comparison between different D-Dimer cutoff values to assess the individual risk of recurrent venous thromboembolism: analysis of results obtained in the DULCIS study

D‐dimer assay, generally evaluated according to cutoff points calibrated for VTE exclusion, is used to estimate the individual risk of recurrence after a first idiopathic event of venous thromboembolism (VTE).

Accuracy of a portable prothrombin time monitor (Coagucheck) in patients on chronic oral anticoagulant therapy: a prospective multicenter study.

A portable prothrombin time (PT) monitor allows patients on oral anticoagulant therapy (OAT) to measure their PT at home. The purpose of the study was to evaluate the accuracy and precision of a portable PT monitor (Coagucheck, Roche Diagnostics, Mannheim, Germany) as compared with laboratory methods. The prospective study was conducted in four centers of the Italian Federation of Anticoagulation Clinics. A one-month instruction phase was followed by a six-month surveillance phase. Seventy-eight subjects on stable OAT (48 men, 30 women, age range: 18-75) were selected on a volunteer basis. Dual measurements of INR values were performed in each subject both from finger capillary blood by the monitor and from venous blood by the Anticoagulation Clinic laboratory in three instruction sessions. The mean difference (bias) of the monitor INR results when compared with the average of laboratory INR and monitor INR results was -0.025 (limits of agreement-LA: -0.84/+0.81 INR units). The mean bias was -0.0675 (LA: -0.37/+0.23), +0.018 (LA: -0.39/+0.35), and +0.039 (LA: -0.49/+0.55), respectively, for INR values lower than 2.0, between 2.0 and 3.0, and greater than 3.0. The overall precision coefficient of monitor INR was 0.370, while it was 0.23, 0.46, 0.29, and 0.21, respectively, in Centers 1, 2, 3, and 4. The overall variation coefficient was 6.5% while it was 3.7%, 8.5%, 4.7%, and 4.9%, respectively, in Centers 1, 2, 3, and 4. Coagucheck has an acceptable level of accuracy for INR values in the range between 2.0 and 3.0. A wide variation in monitor performance was found among centers.

Residual venous obstruction, alone and in combination with D-dimer, as a risk factor for recurrence after anticoagulation withdrawal following a first idiopathic deep vein thrombosis in the prolong study.

OBJECTIVE This study aims to assess the predictive value of residual venous obstruction (RVO) for recurrent venous thrombo-embolism (VTE) in a study using D-dimer to predict outcome. DESIGN This is a multicentre randomised open-label study. METHODS Patients with a first episode of idiopathic VTE were enrolled on the day of anticoagulation discontinuation when RVO was determined by compression ultrasonography in those with proximal deep vein thrombosis (DVT) of the lower limbs. D-dimer was measured after 1 month. Patients with normal D-dimer did not resume anticoagulation while patients with abnormal D-dimer were randomised to resume anticoagulation or not. The primary outcome measure was recurrent VTE over an 18-month follow-up. RESULTS A total of 490 DVT patients were analysed (after excluding 19 for different reasons and 118 for isolated pulmonary embolism (PE)). Recurrent DVT occurred in 19% (19/99) of patients with abnormal D-dimer who did not resume anticoagulation and 10% (31/310) in subjects with normal D-dimer (adjusted hazard ratio: 2.1; p = 0.02). Recurrences were similar in subjects either with (11%, 17/151) or without RVO (13%, 32/246). Recurrent DVT rates were also similar for normal D-dimer, with or without RVO, and for abnormal D-dimer, with or without RVO. CONCLUSIONS Elevated D-dimer at 1 month after anticoagulation withdrawal is a risk factor for recurrence, while RVO at the time of anticoagulation withdrawal is not.