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Background: Exertional dyspnea is a frequently encountered complaint in clinical practice. However, the prevalence of pulmonary embolism (PE) among patients with dyspnea on exertion has not been reported., Objective: The objective of this study was to assess the prevalence of objectively confirmed PE among consecutive patients visiting an emergency department because of recent onset of exertional dyspnea., Methods: Patients aged ≤75 years with recent (<1 month) marked exertional dyspnea had a systematic workup for PE, irrespective of concomitant signs or symptoms of venous thromboembolism and alternative explanations for dyspnea. PE was excluded on the basis of a low pretest clinical probability and normal age-adjusted D-dimer. All other patients had computed tomography pulmonary angiography. An interim analysis after inclusion of 400 patients would stop recruitment if the 95% confidence interval (CI) of the PE prevalence had a lower limit exceeding 20%., Results: The study was prematurely terminated after the inclusion of 417 patients. In 134 patients (32.1%), PE was excluded based on low clinical probability and normal D-dimer. PE was found in 134 (47.3%) of the remaining 283 patients, for an overall prevalence of 32.1% (95% CI, 27.8-36.8). PE was present in 40 of 204 (19.6%) patients without other findings suspicious for PE and in 94 of 213 patients (44.1%) with such findings. PE involved a main pulmonary artery in 37% and multiple lobes in 87% of the patients., Conclusion: The angiographic demonstration of PE is common in patients presenting with recent onset of marked exertional dyspnea, including 20% without other findings suggesting pulmonary embolism., Competing Interests: Conflicts of interest No potential conflict of interest relevant to this article was reported., (Published by Elsevier Inc.)

Background: The long-term risk for recurrent venous thromboembolism (VTE) during extended anticoagulation for a first unprovoked VTE is uncertain., Objectives: To determine the incidence of recurrent VTE during extended anticoagulation of up to 5 years in patients with a first unprovoked VTE., Methods: MEDLINE, EMBASE, and the Cochrane CENTRAL were searched to identify randomized trials and prospective cohort studies reporting recurrent VTE among patients with a first unprovoked VTE who were to receive anticoagulation for a minimum of six additional months after completing ≥3 months of initial treatment. Unpublished data on number of recurrent VTE and person-years, obtained from authors of included studies, were used to calculate study-level incidence rate, and random-effects meta-analysis was used to pool results., Results: Twenty-six studies and 15 603 patients were included in the analysis. During 11 631 person-years of follow-up, the incidence of recurrent VTE and fatal pulmonary embolism per 100 person-years was 1.41 (95% CI, 1.03-1.84) and 0.09 (0.04-0.16), with 5-year cumulative incidences of 7.1% (3.0%-13.2%) and 1.2% (0.4%-4.6%), respectively. The incidence of recurrent VTE was 1.08 (95% CI, 0.77-1.44) with direct oral anticoagulants and 1.55 (1.01-2.20) with vitamin K antagonists. The case-fatality rate of recurrent VTE was 4.9% (95% CI, 2.2%-8.7%)., Conclusions: In patients with a first unprovoked VTE, the long-term risk of recurrent VTE during extended anticoagulation is low but not negligible. Thus, clinicians and patients should be aware of this risk and take appropriate and timely action in case of suspicion of recurrent VTE. Estimates from this study can be used to advise patients on what to expect while receiving extended anticoagulation, and estimate the net clinical benefit of extended treatment to guide long-term management of unprovoked VTE., (© 2021 International Society on Thrombosis and Haemostasis.)

Background: Antiviral drugs are administered in patients with severe COVID-19 respiratory syndrome, including those treated with direct oral anticoagulants (DOACs). Concomitant administration of antiviral agents has the potential to increase their plasma concentration. A series of patients managed in the Cremona Thrombosis Center were admitted at Cremona Hospital for SARS-CoV-2 and started antiviral drugs without stopping DOAC therapy. DOAC plasma levels were measured in hospital and results compared with those recorded before hospitalization., Methods: All consecutive patients on DOACs were candidates for administration of antiviral agents (lopinavir, ritonavir, or darunavir). Plasma samples for DOAC measurement were collected 2to 4 days after starting antiviral treatment, at 12 hours from the last dose intake in patients on dabigatran and apixaban, and at 24 hours in those on rivaroxaban and edoxaban. For each patient, C-trough DOAC level, expressed as ng/mL, was compared with the one measured before hospitalization., Results: Of the 1039 patients hospitalized between February 22 and March 15, 2020 with COVID-19 pneumonia and candidates for antiviral therapy, 32 were on treatment with a DOAC. DOAC was stopped in 20 and continued in the remaining 12. On average, C-trough levels were 6.14 times higher during hospitalization than in the pre-hospitalization period., Conclusion: DOAC patients treated with antiviral drugs show an alarming increase in DOAC plasma levels. In order to prevent bleeding complications, we believe that physicians should consider withholding DOACs from patients with SARS-CoV-2 and replacing them with alternative parenteral antithrombotic strategies for as long as antiviral agents are deemed necessary and until discharge., (© 2020 International Society on Thrombosis and Haemostasis.)

Essentials Currently, DOACs are given at fixed doses and do not require laboratory monitoring. Direct oral anticoagulant-specific measurements were performed at trough and peak. Patients who developed bleeding events showed higher DOAC plasma levels at peak. This study suggests the need of a more accurate DOAC dose assessment., Background: Direct oral anticoagulants (DOACs) are administered at fixed dose. The aim of the study was to evaluate the relationship between DOAC C-trough or C-peak plasma levels and bleeding complications in patients with non-valvular atrial fibrillation (NVAF)., Methods: Five hundred sixty five consecutive naive NVAF patients were enrolled. The DOAC measurements at C-trough and at C-peak (available in 411 patients) were performed at steady state, within the first month of treatment. Major bleeding (MB), clinically relevant non-major bleeding (CRNMB), and minor bleeding (MinB), occurring during 1 year of follow-up after blood sampling, were recorded. For each DOAC, interval of C-trough and C-peak levels was subdivided into four equal classes and results were attributed to these classes; the median values of results were also calculated., Results: Two hundred eight patients were on apixaban, 185 on dabigatran, and 172 on rivaroxaban. For 1-[qqqdeletezzz] year follow up for all patients, we observed: 19 MB (3.36%), 6 CRNMB (1.06%), and 47 MinB (8.31%). The prevalence of bleeding patients with anticoagulant levels in the upper classes of C-peak activity (II + III + IV) was higher than that in the lowest class. Normalized results of C-peak levels were higher in patients with bleeding than in those without bleeding., Conclusions: Bleeding complications during DOAC treatment were more frequent among atrial fibrillation (AF) patients with higher C-peak anticoagulant levels. In addition to a previous study that showed an increased risk of thrombotic complications in the patients with low C-trough levels, this study seems to indicate that patients with NVAF on DOACs would need a more accurate definition of their optimal therapeutic window., (© 2019 The Authors. Journal of Thrombosis and Haemostasis published by Wiley Periodicals, Inc. on behalf of International Society on Thrombosis and Haemostasis.)

Essentials The risk of bleeding influences the duration of anticoagulation (AC) after venous thromboembolism. We assessed the ACCP bleeding risk score in an inception-cohort of patients receiving AC. 53% were categorized at high-risk, but their bleeding rate was low during long-term AC. ACCP score had low predictive value for bleeding., Summary: Background The American College of Chest Physicians (ACCP) guideline proposes a score to decide on extended anticoagulation after an unprovoked venous thromboembolism (VTE). Methods We investigated the ACCP score to predict bleeding risk in an inception cohort of 2263 patients on long-term anticoagulation (1522 treated with vitamin K antagonists [VKAs] and the remaining with direct oral anticoagulants [DOACs]) belonging to the Italian START2 Register. Results More than half the patients were categorized as high risk; nevertheless, a higher proportion received anticoagulation for > 1 year compared with those in the low-risk category. For 3130 years (median 12 [interquartile range 6, 24] months), 48 bleeding outcomes occurred (1.53%/year) in the cohort (1.7%/year and 0.95%/year in high- and low-risk categories, respectively). The c-statistic of the ACCP score was 0.55 (0.48-0.63), 0.50 (0.42-0.58) and 0.56 (0.48-0.64) in low-, moderate- and high-risk categories, respectively. The bleeding incidence was higher during the first 90 days of treatment (3.0%/year) than afterwards (1.2%/year; relative risk (RR), 2.5 [1.3-4.7]), and similar among the three categories. The bleeding rate was not different during the initial 3 months of treatment in patients receiving VKAs or DOACs; it was, however, lower in the latter patients in the subsequent period (0.5%/year vs. 1.4%/year, respectively). Conclusion The bleeding rate during extended treatment was rather low in our patients. ACCP score had insufficiently predictive value for bleeding and cannot be used to guide decisions on extended treatment. New prediction tools for bleeding risk during anticoagulant treatments (including DOACs) are required., (© 2018 The Authors. Journal of Thrombosis and Haemostasis published by Wiley Periodicals, Inc. on behalf of International Society on Thrombosis and Haemostasis.)

Essentials Direct oral anticoagulants (DOACs) do not require laboratory monitoring currently. DOAC specific measurements were performed at trough in patients with atrial fibrillation. Patients who developed thromboembolic events showed lower DOAC plasma levels. This study supports the concept of measuring DOAC levels at steady state., Summary: Background Direct oral anticoagulants (DOACs) are administered at fixed doses without the need for dose adjustment according to laboratory testing. High interindividual variability in drug blood levels has been shown with all DOACs. To evaluate a possible relationship between DOAC C-trough anticoagulant levels and thromboembolic events, 565 consecutive naive patients with atrial fibrillation (AF) were enrolled in this study performed within the START Laboratory Registry. Methods DOAC-specific measurements (diluted thrombin time or anti-activated factor II calibrated for dabigatran; anti-activated FX calibrated for rivaroxaban or apixaban) at C-trough were performed locally at steady state within 15-25 days after the start of treatment. For each DOAC, the interval of C-trough levels, from the limit of quantification to the highest value, was subdivided into four equal classes, and results were attributed to these classes; the median values of results were also calculated. Thromboembolic complications occurring during 1 year of follow-up were recorded. Results Thromboembolic events (1.8%) occurred in 10 patients who had baseline C-trough levels in the lowest class of drug levels. The incidence of thromboembolic events among patients with DOAC C-trough levels in the lowest level class was 2.4%, and that in the remaining groups was 0%. The patients with thrombotic complications also had a higher mean CHA 2 DS 2 -VASc score than that of the total patient population: 5.3 (95% confidence interval [CI] 4.3-6.3 versus 3.0 (95% CI 2.9-3.1). Conclusion In this study cohort, thrombotic complications occurred only in DOAC-treated AF patients who had very low C-trough levels, with a relatively high CHA 2 DS 2 -VASc score. Larger studies are warranted to confirm these preliminary observations., (© 2018 The Authors. Journal of Thrombosis and Haemostasis published by Wiley Periodicals, Inc. on behalf of International Society on Thrombosis and Haemostasis.)

Essentials Predicting recurrences may guide therapy after unprovoked venous thromboembolism (VTE). We evaluated the DASH score in 827 patients with unprovoked VTE to verify prediction accuracy. A DASH score ≤ 1 had a cumulative recurrence risk at 1 year of 3.6%, as predicted by the model. The DASH score performed better in younger (< 65 years old) subjects., Summary: Background The DASH prediction model has been proposed as a guide to identify patients at low risk of recurrence of venous thromboembolism (VTE), but has never been validated in an independent cohort. Aims To validate the calibration and discrimination of the DASH prediction model, and to evaluate the DASH score in a predefined patient subgroup aged > 65 years. Methods Patients with a proximal unprovoked deep vein thrombosis (DVT) or pulmonary embolism (PE) who received a full course of vitamin K antagonist or direct oral anticoagulant (> 3 months) and had D-dimer measured after treatment withdrawal were eligible. The DASH score was computed on the basis of the D-dimer level after therapy withdrawal and personal characteristics at the time of the event. Recurrent VTE events were symptomatic proximal or distal DVT/PE, and were analyzed with a time-dependent analysis. Observed 12-month and 24-month recurrence rates were compared with recurrence rates predicted by the DASH model. Results We analyzed a total of 827 patients, of whom 100 (12.1%) had an objectively documented recurrence. As compared with the original DASH cohort, there was a greater proportion of subjects with a 'low-risk' (≤ 1) DASH score (66.3% versus 51.6%, P < 0.001). The slope of the observed versus expected cumulative incidence at 2 years was 0.71 (95% confidence interval 0.51-1.45). The c-statistic was lower for subjects aged > 65 years (0.54) than for younger subjects (0.72). Conclusions These results confirm the validity of DASH prediction model, particularly in young subjects. The recurrence risk in elderly patients (> 65 years) was, however, > 5% even in those with the lowest DASH scores., (© 2017 International Society on Thrombosis and Haemostasis.)

Essentials Prothrombin and partial thromboplastin time (PT/PTT) measure direct oral anticoagulants (DOACs). PT, PTT and specific tests for DOACs were performed on patients treated for atrial fibrillation. Normal PT/PTT don't exclude DOAC activity and their prolongation doesn't confirm DOAC action. The use of PT or PTT to evaluate DOAC activity could cause dangerous misinterpretations., Summary: Background Prothrombin time (PT) and activated partial thromboplastin time (APTT) have been proposed to measure the effect of oral anti-activated factor X (FXa) or anti-activated FII drugs, respectively. Aims To evaluate the relationships and responsiveness of PT and APTT versus direct oral anticoagulant (DOAC) concentrations measured with specific coagulation tests performed with different platforms in four Italian anticoagulation clinics. Methods Six hundred and thirty-five patients with atrial fibrillation participated in the study: 240 were receiving dabigatran, 264 were receiving rivaroxaban, and 131 were receiving apixaban. Blood was taken at trough and peak within the first month (15-25 days) of treatment. PT, APTT, diluted thrombin time (dTT) calibrated for dabigatran and anti-FXa calibrated for rivaroxaban or apixaban were determined. Results For dabigatran, the correlation between APTT and dTT ranged from r = 0.80 to r = 0.62. For rivaroxaban, the correlation between the anti-FXa assay and PT ranged from r = 0.91 to r = 0.73. For apixaban, the correlation between the anti-FXa assay and PT was lower than for the two other drugs (r = 0.81 to r = 0.54). Despite the above significant correlations, the responsiveness of PT or APTT was relatively poor. A discrepancy between global testing and DOAC plasma concentrations was shown in a considerable proportion of patients, depending on the platform and drug, with values ranging from 6% to 62%. Conclusions Overall, poor responsiveness of the screening tests to DOAC concentrations was observed. PT and APTT normal values cannot exclude DOAC anticoagulant activity, and PT or APTT prolongation is not always associated with DOAC anticoagulant effect as determined with specific tests., (© 2016 International Society on Thrombosis and Haemostasis.)

Background: In order to stratify patients with a first unprovoked venous thromboembolism (VTE) according to their recurrence risk and to identify those who would actually benefit from indefinite anticoagulation, three prediction models have been developed so far; none of them has been yet externally validated., Objective: To externally validate the Vienna Prediction Model (VPM), a prediction guide for estimating the recurrence risk after a first unprovoked VTE developed through Cox modeling and including sex, D-dimer and index VTE site as predictors., Patients/methods: Nine hundred and four patients pooled from five prospective studies evaluating the prognostic value of D-dimer for VTE recurrence served as the validation cohort. The validity of the VPM in stratifying patients according to their relative recurrence risk (discrimination) and in predicting the absolute recurrence risk (calibration) was tested with survival analysis methods., Results: The ability of the VPM to distinguish patients' risk for recurrent VTE in the validation cohort was at least as good as in the original cohort, with a calibration slope of 1.17 (95% confidence interval 0.71-1.64; P = 0.456 for the hypothesis of a significant difference from 1), and a c-statistic of 0.626 (vs. 0.651 in the original derivation cohort). The VPM absolute predictions in terms of cumulative rates tended to underestimate the observed recurrence rates at 12 months., Conclusions: By using a pooled individual patient database as a validation cohort, we confirmed the ability of the VPM to stratify patients with a first unprovoked VTE according to their risk of recurrence., (© 2015 International Society on Thrombosis and Haemostasis.)

Background: The optimal duration of anticoagulant treatment after venous thromboembolism (VTE) should be evaluated in relation to bleeding risk. This assessment is particularly difficult with elderly patients, because of their increased risk of both recurrences and hemorrhages. Bleeding risk stratification models have been proposed, but their predictive ability in very elderly patients is unknown. We aimed to assess six bleeding stratification models in this setting, by using information available in our dataset., Patients and Methods: Patients aged ≥ 80 years receiving vitamin K antagonists (VKAs) for the secondary prevention of VTE were eligible for this prospective cohort study. All patients were followed at Italian anticoagulation clinics for monitoring of VKA treatment. Risk factors for bleeding were collected, and major bleeding events and mortality were documented during follow-up. The association of bleeding events with the available risk factors was tested by means of Cox regression analysis; the c-statistic was used to quantify the predictive validity of the classification schemes., Results: A total of 1078 patients (37.2% males; mean age, 84 years) were enrolled in the study, for a total observation period of 1981 patient-years. The rate of major bleeding was 2.4 per 100 patient-years (47 events; one was fatal). The mortality rate was 5.2 per 100 patient-years. None of the considered risk factors were significantly associated with bleeding events. The predictive validity of the risk stratification models was low, and the most accurate model was not specifically developed for VTE patients (HEMORR2 HAGES, c-statistic 0.60, 95% confidence interval 0.49-0.70)., Conclusions: Bleeding risk stratification models appear to have little accuracy in very elderly VTE patients., (© 2013 International Society on Thrombosis and Haemostasis.)

Background: Pretest clinical probability with the Wells rule and D-dimer have been widely investigated for the diagnosis of symptomatic proximal deep vein thrombosis (DVT) of the lower limbs, but they have not been formally tested for symptomatic isolated distal DVT diagnosis., Objective: To evaluate the diagnostic accuracy of the Wells rule and D-dimer for isolated distal DVT., Design, Setting, and Patients: This was a single-center, cross-sectional study including 873 consecutive outpatients with suspected DVT, in whom pretest clinical probability determination, D-dimer determination (STA Liatest; cut-off of < 500 ng mL(-1) ) and complete compression ultrasonography of both lower limbs were performed., Results: The isolated distal DVT prevalence was 12.4% (90/725). The sensitivity of the Wells rule for isolated distal DVT was 47% (95% confidence interval [CI] 36-57%), the specificity was 74% (95% CI 70-77%), and the negative and positive predictive values were 91% (95% CI 88-93%) and 20% (95% CI 15-26%), respectively. Patients with isolated distal DVT had higher D-dimer levels than patients without DVT (1759 ± 1576 vs. 862 ± 1079 ng mL(-1) , P = 0.0001). D-dimer was negative in 13 patients with isolated distal DVT. D-dimer sensitivity and specificity for isolated distal DVT were 84% (95% CI 75-91%) and 50% (95% CI 46-54%), respectively, with a negative predictive value of 96% (95% CI 93-98%). In patients with low pretest clinical probability, the D-dimer negative predictive value was 99% (95% CI 95-100%)., Conclusion: In clinically suspected DVT with negative proximal compression ultrasonography, pretest clinical probability with the Wells rule has a low diagnostic accuracy for isolated distal DVT. D-dimer has a better negative predictive value, but alone it does not exclude isolated distal DVT. In patients with low pretest clinical probability, D-dimer had a negative predictive value of > 95% for isolated distal DVT., (© 2012 International Society on Thrombosis and Haemostasis.)

In this overview we address the three phase III studies that compared new oral anticoagulants (dabigatran, rivaroxaban and apixaban) with warfarin in the setting of stroke prevention in atrial fibrillation. Strengths and weaknesses of the studies were examined in detail through indirect comparison. We analyze and comment the inclusion and exclusion criteria, the characteristics of randomized patients, the primary efficacy and safety end points and side effects. All new oral anticoagulants resulted in being non-inferior to vitamin K antagonists in reducing stroke or systemic embolism in patients with atrial fibrillation. Dabigatran 150 mg and apixaban were superior to vitamin K antagonists. Importantly, new oral anticoagulants significantly reduced hemorrhagic stroke in all three studies. Major differences among new oral anticoagulants include the way they are eliminated and side effects. Both dabigatran and apixaban were tested in low- to moderate-risk patients (mean CHADS2 [Congestive heart failure, Hypertension, Age, Diabetes, Stroke] score = 2.1-2.2) whereas rivaroxaban was tested in high-risk patients (mean CHADS2 score = 3.48) and at variance with dabigatran and apixaban was administered once daily. Apixaban significantly reduced mortality from any cause. The choice of a new oral anticoagulant should take into account these and other differences between the new drugs., (© 2012 International Society on Thrombosis and Haemostasis.)

Background: Little information is available on the long-term clinical outcome of cerebral vein thrombosis (CVT)., Objectives and Methods: In an international, retrospective cohort study, we assessed the long-term rates of mortality, residual disability and recurrent venous thromboembolism (VTE) in a cohort of patients with a first CVT episode., Results: Seven hundred and six patients (73.7% females) with CVT were included. Patients were followed for a total of 3171 patient-years. Median follow-up was 40 months (range 6, 297 months). At the end of follow-up, 20 patients had died (2.8%). The outcome was generally good: 89.1% of patients had a complete recovery (modified Rankin Score [mRS] 0-1) and 3.8% had a partial recovery and were independent (mRS 2). Eighty-four per cent of patients were treated with oral anticoagulants and the mean treatment duration was 12 months. CVT recurred in 31 patients (4.4%), and 46 patients (6.5%) had a VTE in a different site, for an overall incidence of recurrence of 23.6 events per 1000 patient-years (95% confidence Interval [CI] 17.8, 28.7) and of 35.1 events/1000 patient-years (95% CI, 27.7, 44.4) after anticoagulant therapy withdrawal. A previous VTE was the only significant predictor of recurrence at multivariate analysis (hazard ratio [HR] 2.70; 95% CI 1.25, 5.83)., Conclusions: The long-term risk of mortality and recurrent VTE appears to be low in patients who survived the acute phase of CVT. A previous VTE history independently predicts recurrent events., (© 2012 International Society on Thrombosis and Haemostasis.)

Background: Optimal doses and duration of low-molecular-weight heparin (LMWH) for the treatment of superficial vein thrombosis (SVT) are still uncertain., Objectives: To compare the efficacy and safety of different doses and durations of LMWH parnaparin for symptomatic lower limb SVT., Patients and Methods: Outpatients with at least a 4-cm-long SVT of long or short saphenous veins or their collaterals were randomized to receive parnaparin either 8500 UI once daily ( o.d.) for 10 days followed by placebo for 20 days (group A) or 8500 UI o.d. for 10 days followed by 6400 UI once daily (o.d.) for 20 days (group B) or 4250 UI o.d. for 30 days (group C) in a double-blind fashion in 16 clinics. Primary outcome was the composite of symptomatic and asymptomatic deep vein thrombosis (DVT), symptomatic pulmonary embolism (PE) and relapse and/or symptomatic or asymptomatic SVT recurrence in the first 33 days with 60 days follow-up., Results: Among 664 patients, primary outcome occurred in 33/212 (15.6%), 4/219 (1.8%) and 16/217 (7.3%) subjects in groups A, B and C, respectively (B vs. A: absolute risk reduction [ARR]: 13.7%, 95% confidence intervals [CI]: 8-18.9 P<0.001; B vs. C: ARR: 5.5%; 95% CI: 1.6-9.4 P= 0.011; C vs. A: ARR: 8.2%, 95% CI: 2-14 P=0.012). During days 0-93, the event rate was higher in group A (22.6%) than either in group B (8.7%; P=0.001) or C (14.3%, P=0.034). No major hemorrhages occurred., Conclusions: An intermediate dose of parnaparin for 30 days is superior to either a 30-day prophylactic dose or a 10-day intermediate dose for lower limb SVT treatment., (© 2012 International Society on Thrombosis and Haemostasis.)

Background: In patients with unprovoked venous thromboembolism (VTE), the optimal duration of anticoagulation is anchored on estimating the risk of disease recurrence., Objectives: We aimed to develop a score that could predict the recurrence risk following a first episode of unprovoked VTE, pooling individual patient data from seven prospective studies., Methods: One thousand eight hundred and eighteen cases with unprovoked VTE treated for at least 3 months with a vitamin K antagonist were available for analysis. Optimism-corrected Cox regression coefficients were used to develop a recurrence score that was subsequently internally validated by bootstrap analysis., Results: Abnormal D-dimer after stopping anticoagulation, age <50 years, male sex and VTE not associated with hormonal therapy (in women) were the main predictors of recurrence and were used to derive a prognostic recurrence score (DASH, D-dimer, Age, Sex, Hormonal therapy) showing a satisfactory predictive capability (ROC area =0.71). The annualized recurrence risk was 3.1% (95% confidence interval [CI], 2.3-3.9) for a score ≤ 1, 6.4% (95% CI, 4.8-7.9) for a score=2 and 12.3% (95% CI, 9.9-14.7) for a score ≥ 3. By considering at low recurrence risk those patients with a score ≤ 1, life-long anticoagulation might be avoided in about half of patients with unprovoked VTE., Conclusions: The DASH prediction rule appears to predict recurrence risk in patients with a first unprovoked VTE and may be useful to decide whether anticoagulant therapy should be continued indefinitely or stopped after an initial treatment period of at least 3 months., (© 2012 International Society on Thrombosis and Haemostasis.)

Thromboses that are restricted to the infra-popliteal deep veins of the lower limbs (isolated distal deep vein thrombosis, IDDVT) are frequently diagnosed in subjects with suspected pulmonary embolism (PE; 7–10%) or DVT(4–15%), accounting for 31–56% of all diagnosed leg DVTs. Despite their frequency, IDDVTs still remain one of the most debated issues in the field of venous thromboembolism (VTE). Conflicting clinical results have resulted in differing opinions on the need to test for IDDVTs and how to treat them. Due to discordant results, the real risk of IDDVT-associated PE is not well established. IDDVTs are associated with (i) lower risk of recurrence when compared with other VTEs, and (ii) fewer late sequelae than proximal DVT. Diagnosis of IDDVT is based on ultrasound examination of all calf veins, which is more operator-dependent and less sensitive than proximal vein examination. A series of studies has shown, however, that a single complete ultrasound strategy in symptomatic patients has comparable clinical results to serial proximal ultrasound, allowing approximately 15% better DVT diagnosis. Optimal treatment of IDDVT is still controversial. Guidelines recommend anticoagulation for 12 weeks, although 6 weeks may be sufficient. There is, however, insufficient data to support the diagnosis and treatment of all IDDVTs, and the necessary criteria to identify subjects at higher risk of complication are lacking. It also seems likely that different approaches may be better for unprovoked or secondary events and for deep or muscle veins. Specifically designed and adequately powered clinical studies addressing the issue of IDDVT need to be urgently undertaken.

Aim: To determine if the mode of presentation of venous thromboembolism (VTE), as deep vein thrombosis (DVT) or pulmonary embolism (PE), predicts the likelihood and type of recurrence., Methods: We carried out a patient-level meta-analysis of seven prospective studies in patients with a first VTE who were followed after anticoagulation was stopped. We used Kaplan-Meier analysis to determine the cumulative incidence of recurrent VTE according to mode of presentation, and multivariable Cox regression to calculate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for mode of and extent of DVT as potential risk factors for recurrence., Results: The 5-year cumulative rate of recurrent VTE in 2554 patients was 22.6%. In 869 (36.1%) patients with PE, the 5-year rate of any recurrence (DVT or PE) was 22.0%, and recurrence as PE was 10.6%. In 1365 patients with proximal DVT, the 5-year recurrence rate was 26.4%, and recurrence with PE was 3.6%. The risk of recurrence as PE was 3.1-fold greater in patients presenting with symptomatic PE than in patients with proximal DVT (HR, 3.1; 95% CI, 1.9-5.1). Patients with proximal DVT had a 4.8-fold higher cumulative recurrence rate than those with distal DVT (HR, 4.8; 95% CI, 2.1-11.0)., Conclusion: Whilst DVT and PE are manifestations of the same disease, the phenotypic expression is predetermined. Patients presenting with PE are three times more likely to suffer recurrence as PE than patients presenting with DVT. Patients presenting with calf DVT are at low risk of recurrence and at low risk of recurrence as PE., (© 2010 International Society on Thrombosis and Haemostasis.)

Background: The PROLONG randomized study showed that patients with an abnormal D-dimer after anticoagulation suspension for a first unprovoked episode of venous thromboembolism (VTE) benefited from anticoagulation resumption. Patients with normal D-dimer after anticoagulation suspension had a low recurrence rate (4.4% patient-years) but their anticoagulation optimal duration remained uncertain., Objectives: To assess whether sex and age, in combination with normal D-dimer, are risk factors for VTE recurrence in patients enrolled in the PROLONG study extended follow-up., Methods: D-dimer was measured at 1 month after anticoagulation suspension. Patients with a normal D-dimer did not resume anticoagulants, whereas patients with an abnormal D-dimer were randomized either to resume or not anticoagulants. Primary outcome was recurrent VTE., Results: After excluding patients resuming anticoagulants for abnormal D-dimer, recurrences were higher in males than females [7.4% patient-years - 47/639 vs. 4.3% patient-years - 27/626; hazard ratio (HR) = 1.7; P = 0.027] and in patients aged 65 or older than in younger patients (8.4% patient-years - 50/598 vs. 3.6% patient-years - 24/667; HR = 2.1; P = 0.003). In patients with normal D-dimer and younger than 65, recurrences were higher in males than in females (5.1% vs. 0.4% patient-years; adjusted HR = 10.6; P = 0.023) and both females and males aged 65 years or older had more recurrences (6.6% and 8.1% patient-years, respectively, adjusted HR: 16.0; P = .008 and 16.0; P = 0.008, respectively) than females younger than 65., Conclusions: In patients with idiopathic VTE and a normal D-dimer at 1 month after anticoagulation suspension, females younger than 65 had a very low risk of recurrence., (© 2010 International Society on Thrombosis and Haemostasis.)

Background: A number of variables have been evaluated for risk stratification in patients with acute pulmonary embolism (PE). Whereas increased D-dimer levels have been associated with mortality at 3 months, its role in predicting short-term outcome (the period of time during which any therapeutic decision has to be taken) remains unclear., Methods: RIETE is an ongoing, prospective registry of consecutive patients with acute venous thromboembolism. We assessed the prognostic value of D-dimer levels at baseline, measured with an automated latex agglutination test (IL Test D-dimer), on the 15-day outcome in patients with acute PE. Overall mortality, fatal PE and major bleeding rates were compared by quartile., Results: As of February 2008, 1707 patients with acute PE underwent D-dimer testing. Of these, 72 patients (4.2%) died during the first 15 days, 11 (0.6%) had recurrent PE, and 29 (1.7%) had major bleeding. Overall mortality increased with increasing D-dimer levels, from 2.7% in the first quartile (< 1050 ng mL(-1)) to 7.0% in the fourth quartile (>or= 4200 ng mL(-1)). The rates of fatal PE and major bleeding also increased. On multivariate analysis, patients with D-dimer levels in the fourth quartile had an increased risk for overall death (odds ratio, 1.8; 95% CI, 1.1-3.2), fatal PE (odds ratio, 2.0; 95% CI, 1.0-3.8) or major bleeding (odds ratio, 3.2; 95% CI, 1.5-7.0)., Conclusions: PE patients with D-dimer levels in the fourth quartile had an increased incidence of overall death, fatal PE and major bleeding within 15 days both before and after multivariate adjustment.

Background: Increased demand for oral anticoagulation has resulted in wider adoption of computer-assisted dosing in anticoagulant clinics. An economic evaluation has been performed to investigate the cost-effectiveness of computer-assisted dosing in comparison with manual dosing in patients on oral anticoagulant therapy., Methods: A trial-based cost-effectiveness analysis was conducted as part of the EAA randomized study of computer-assisted dosage vs. manual dosing. The 4.5-year multinational trial was conducted in 32 centres with 13 219 anticoagulation patients randomized to manual or computer-assisted dosage. The main outcome measures were total health care costs, clinical event rates and cost-saving per clinical event prevented by computer dosing compared with manual dosing., Results: Mean dosing costs per patient were lower (difference: euro47) for computer-assisted dosing, but with little difference in clinical event costs. Total overall costs were euro51 lower in the computer-assisted dosing arm. There were a larger number of clinical events in the manual dosing arm. The overall difference between trial arms was not significant (difference in clinical events, -0.003; 95% CI, -0.010-0.004) but there was a significant reduction in events with DVT/PE, suggesting computer-assisted dosage with the two study programs (dawn ac or parma 5) was at least as effective clinically as manual dosage. The cost-effectiveness analysis indicated that computer-assisted dosing is less costly than manual dosing., Conclusions: Results indicate that computer-assisted dosage with the two programs (dawn ac and parma 5) is cheaper than manual dosage and is at least as effective clinically, indicating that investment in this technology represents value for money.

Background: The assessment of the risk of recurrent venous thromboembolism (VTE) is important to determine the optimal duration of secondary prophylaxis. The risk can be estimated by measuring individual parameters reflecting hypercoagulability. Because of the large numbers of such putative parameters, the assessment in individual patients is complex. Application of global assays reflecting the pro-/anti-coagulant balance in vivo would be desirable., Objectives: To investigate the relationship between recurrent VTE and thrombin generation (TG)., Patients-Methods: Two hundred and fifty-four patients were followed-up after a first episode of unprovoked, objectively documented VTE for a period of 2.7 years after discontinuation of treatment with vitamin K antagonists. TG was measured 1 month after discontinuation of treatment as endogenous thrombin potential (ETP), peak thrombin and lag-time in the presence or absence of thrombomodulin. The study outcome was objectively documented symptomatic recurrent VTE., Results: Patients with ETP or peak (measured in the presence of thrombomodulin) of >960 nm(*)min or >193 nm had hazard ratios (HR) (95% CI) for recurrent VTE of 3.41 (1.34-8.68) or 4.57 (1.70-12.2) as compared with those with an ETP <563 nm(*)min or peak <115 nm. Patients with lag-time <14.5 min had HR of 3.19 (1.29-7.89) as compared with those with lag-time >20.8 min. HR for ETP, peak or lag-time measured in the absence of thrombomodulin were smaller than those measured in the presence of thrombomodulin., Conclusions: The measurement of TG helps to identify patients at higher risk of VTE recurrence. The increased risk may be better appreciated if the test is performed in the presence of thrombomodulin.

Background: Increased demand for oral anticoagulants is overwhelming facilities worldwide, resulting in increasing use of computer assistance. A multicenter clinical endpoint study has been performed to compare the safety and effectiveness of computer-assisted dosage with dosage by experienced medical staff at the same centers., Methods: A randomized study of dosage of two commercial computer-assisted dosage programs (PARMA 5 and DAWN AC) vs. manual dosage at 32 centers with an established interest in oral anticoagulation in 13 countries. The aim was to recruit a minimum of 16,000 patient-years randomized to medical staff or computer-assisted dosage. In total, 13,219 patients participated, 6503 patients being randomized to medical staff and 6716 to computer-assisted dosage. The safety and effectiveness of computer-assisted dosage were compared with those of medical staff dosage., Results: In total, 13,052 patients were recruited (18,617 patient-years). International Normalized Ratio (INR) tests numbered 193 890 with manual dosage and 193,424 with computer-assisted dosage. The number of clinical events with computer-assisted dosage was lower (P = 0.1), but in the 3209 patients with deep vein thrombosis/pulmonary embolism, they were reduced by 37 (24%, P = 0.001). Time in target INR range was significantly improved by computer assistance as compared with medical staff dosage at the majority of centers (P < 0.001)., Conclusions: The safety and effectiveness of computer-assisted dosage has been demonstrated using two different marketed programs in comparison with experienced medical staff dosage at the centers with established interest in anticoagulation. Significant prevention of clinical events in patients with deep vein thrombosis/pulmonary embolism and the achievement of target INR in all clinical groups has been observed. The reliability and safety of other marketed computer-assisted dosage programs need to be established.

Objectives: To assess the prevalence of risk factors for venous thromboembolism (VTE) and the prevalence of recent (<1 year) VTE [including superficial vein thrombosis (SVT), deep vein thrombosis (DVT) and pulmonary embolism (PE)] amongst patients attending general practitioner (GP) surgeries., Design: Multicentre, cross-sectional, observational study., Setting: A total of 1536 GP surgeries., Participants: A total of 15 180 adult, co-operative subjects, who had consulted their GP for a health disorder and signed the informed consent form., Interventions: None., Main Outcome Measures: Prevalence of known VTE risk factors graded according to importance and prevalence of recent (<1 year) VTE events (including SVT), based on interviews., Results: About 1:5 patients had at least one strong risk factor and about 1:20 had at least two risk factors, with no difference between sexes. The prevalence of strong risk factors increased with age. Most were related to medical conditions: history of SVT and/or DVT/PE, heart failure and malignancy. About 3:4 women and 2:3 men had at least one moderate to weak risk factor; nearly 1:2 women and 1:3 men had at least two moderate to weak risk factors. The most common were: history of VTE, smoking, history of miscarriage, estrogen therapy, obesity, and varicose veins. Overall, 80% women and 67% men had at least one risk factor, and 50% women and 35% men had at least two risk factors. The prevalence of recent (<1 year) VTE was 3.4% in women and 2.4% in men, and increased with age. The majority of cases were SVT in both sexes (2.5% in women and 1.5% in men)., Conclusions: The prevalence of risk factors for VTE amongst patients attending GP surgeries is high. GPs should bear this in mind during their daily practice.

Background and Aim: Several factors are associated with an increased risk of recurrent venous thromboembolism (VTE). The aim of the study was to investigate whether the quality of oral anticoagulation therapy (OAT) is a long-term risk factor for recurrence of VTE after OAT interruption., Methods and Results: A total of 297 patients (170 males) with a recent acute unprovoked VTE episode were prospectively monitored during OAT in our anticoagulation clinic and followed up for 21 months after OAT interruption. Recurrent events were recorded in 42 subjects for 493 years of follow-up [14.1% of patients; 8.5% patient-years (pt-y)] after OAT withdrawal. The rate of recurrence was not correlated to OAT duration. Subjects experiencing recurrence after OAT interruption had spent significantly more time at markedly subtherapeutic international normalized ratio (INR) levels (<1.5) and less time within the therapeutic range (2.0-3.0 INR) during OAT. Relative risk (RR) of recurrence was significantly higher [2.77 (95% confidence interval (CI) 1.49-5.18; P = 0.001) and 2.70 (95% CI 1.39-5.25; P = 0.003) at univariate and multivariate analysis, respectively] in those who spent more time (upper quintile) at INR values <1.5, being especially evident in the first 90 days of OAT. RR was significantly higher at univariate [2.05 (95% CI 1.07-3.96; P = 0.031)] but not at multivariate [1.98 (95% CI 0.98-4.0; P = 0.056)] analysis when the entire OAT period was considered. Subjects in the upper quintile of time spent at INR values <1.5 had significantly higher D-dimer values when OAT was stopped and after 3 months., Conclusions: The amount of time that subjects with an acute unprovoked VTE event spend at near-normal INR values (<1.5) during the first 3 months of treatment is associated with higher D-dimer values measured during OAT and after its interruption and is a significant risk factor for late VTE recurrence.

Background: Reliable risk estimates for venous thrombosis in families with inherited thrombophilia are scarce but necessary for determining optimal screening and treatment policies., Objectives: In the present analysis, we determined the risk of a first venous thrombotic event in carriers of a thrombophilic defect (i.e. antithrombin-, protein C- or protein S deficiency, or factor V Leiden)., Patients and Methods: The asymptomatic carriers had been tested prior to this study in nine European thrombosis centers because of a symptomatic carrier in the family, and were followed prospectively for 5.7 years on average between March 1994 and January 2001. Annually, data were recorded on the occurrence of risk situations for venous thrombosis and events (e.g. venous thrombosis, death)., Results: Twenty-six of the 575 asymptomatic carriers (4.5%) and seven of the 1118 controls (0.6%) experienced a first deep venous thrombosis or pulmonary embolism during follow-up. Of these events, 58% occurred spontaneously in the carriers compared with 43% in the controls. The incidence of first events was 0.8% per year (95% CI 0.5-1.2) in the carriers compared with 0.1% per year (95% CI 0.0-0.2) in the controls. The highest incidence was associated with antithrombin deficiency or combined defects, and the lowest incidence with factor V Leiden., Conclusions: The incidence of venous events in asymptomatic individuals from thrombophilic families does not exceed the risk of bleeding associated with long-term anticoagulant treatment in the literature (1-3%).

Background: We started a large multicenter prospective follow-up study to provide reliable risk estimates of venous thrombosis in families with various thrombophilic defects., Objectives: This paper describes data collected at study entry on venous events experienced before study inclusion, i.e. the baseline data., Patients/methods: All individuals (probands, relatives) registered in nine European thrombosis centers with the factor (F)V Leiden mutation, a deficiency of antithrombin, protein C or protein S, or a combination of these defects, were enrolled between March 1994 and September 1997. As control individuals, partners, friends or acquaintances of the thrombophilic participants were included. Incidence and relative risk of objectively confirmed venous thrombotic events (VTEs) prior to entry were calculated for the relatives with thrombophilia and the controls., Results: Of the 846 relatives with thrombophilia (excluding probands), 139 (16%) had experienced a VTE with an incidence of 4.4 per 1000 person years. Of the controls, 15 of the 1212 (1%) controls had experienced a VTE with an incidence of 0.3 per 1000 person years. The risk of venous thrombosis associated with familial thrombophilia was 15.7 (95% CI 9.2-26.8) and remained similar after adjustment for regional and sex-effects (16.4; 95% CI 9.6-28.0). The highest incidence per 1000 person years was found in relatives with combined defects (8.4; 95% CI 5.6-12.2), and the lowest incidence was found in those with the FV Leiden mutation (1.5; 95% CI 0.8-2.6)., Conclusions: Considerable differences in the lifetime risk of VTE were observed among individuals with different thrombophilia defects.

Background: As the placental vessels are dependent on the normal balance of procoagulant and anticoagulant mechanisms, inherited thrombophilia may be associated with fetal loss., Objectives: We performed a prospective study to investigate the relation between inherited thrombophilia and fetal loss, and the influence of thromboprophylaxis on pregnancy outcome., Patients and Methods: Women were enrolled in the European Prospective Cohort on Thrombophilia (EPCOT). These included women with factor (F)V Leiden or a deficiency of antithrombin, protein C or protein S. Controls were partners or acquaintances of thrombophilic individuals. A total of 191 women (131 with thrombophilia, 60 controls) had a pregnancy outcome during prospective follow-up. Risk of fetal loss and effect of thromboprophylaxis were estimated by frequency calculation and Cox regression modelling., Results: The risk of fetal loss appeared slightly increased in women with thrombophilia without a previous history of fetal loss who did not use any anticoagulants during pregnancy (7/39 vs. 7/51; relative risk 1.4; 95% confidence interval 0.4, 4.7). Per type of defect the relative risk varied only minimally from 1.4 for FV Leiden to 1.6 for antithrombin deficiency compared with control women. Prophylactic anticoagulant treatment during pregnancy in 83 women with thrombophilia differed greatly in type, dose and duration, precluding solid conclusions on the effect of thromboprophylaxis on fetal loss. No clear benefit of anticoagulant prophylaxis was apparent., Conclusions: Women with thrombophilia appear to have an increased risk of fetal loss, although the likelihood of a positive outcome is high in both women with thrombophilia and in controls.

The G20210A prothrombin mutation, associated with elevated prothrombin levels, is a risk factor for venous thromboembolism (VTE) and displays a strong interaction with oral contraceptives (OC). No data are available on VTE risk of OC use in women with high prothrombin levels, either associated or not with the mutation. The aim of this study was to evaluate the risk of VTE in OC users with high prothrombin levels, either including or excluding carriers of the prothrombin mutation. Prothrombin levels were measured by a chromogenic assay in 152 women who suffered from VTE in reproductive age and in 296 healthy women. Subjects carrying thrombophilic alterations other than the G20210A prothrombin mutation were excluded. Prothrombin levels were stratified into quartiles. The OR of subjects in the upper quartile were 3.10 [95% confidence interval (CI) 1.73-5.55] and 2.07 (95% CI 1.11-3.85) in all women and in those not carrying the prothrombin mutation, respectively. Among the 152 patients, 88 had experienced VTE during OC; in the control group we considered as OC users the women who had used OC for at least 6 months in the 2 years before presentation but had stopped the treatment at least 3 months before the time of blood sampling (n = 127). For the interaction between OC and prothrombin levels only the two extreme strata of prothrombin were considered. Women with the lowest prothrombin levels and who did not use OC were used as reference category. The VTE risk of using OC in subjects with prothrombin levels in the upper quartile was increased 5.4-fold (95% CI 2.38-12.3) and 3.5-fold (95% CI 1.48-8.22) in all women and in those not carrying the prothrombin mutation, respectively. We conclude that elevated prothrombin levels, even in women without the G20210A prothrombin mutation, are associated with an increased risk for venous thromboembolism and that oral contraceptive use potentiates such association.