Peripheral arterial disease has a strong impact on cardiovascular outcome in patients with acute coronary syndromes: from the START Antiplatelet registry.

BACKGROUND: Peripheral arterial disease (PAD) was reported to increase the risk of new cardiovascular events in patients with acute coronary syndromes (ACS). However, most of the evidence comes from randomized clinical trials. We aimed to assess the impact of PAD on cardiovascular outcome and treatment decisions in ACS patients in a current real-life setting. METHODS: START-ANTIPLATELET is a multicenter registry enrolling ACS patient. Baseline clinical characteristics and treatment at discharge were recorded and follow-up was repeated at 6-months and 1-year. PAD was defined as intermittent claudication and/or previous revascularization. RESULTS: Among 1442 patients enrolled, 103 (7.1%) had PAD. PAD patients were older (71.8 ± 10.6vs66.2 ± 12.6 yrs., p < 0.0001), more frequently hypertensive (90.3vs68.6%, p< 0.0001), hypercholesterolemic (66vs52%, p= 0.037), diabetic (51.5vs24%, p= 0.0001), obese (28.2vs19.3%, p= 0.029) and with previous TIA (7.8vs2.8%, p= 0.005) or stroke (11.7vs3.1%, p< 0.0001). Clinical presentation and acute treatment were similar in non-PAD and PAD patients, but the latter were discharged significantly less frequently on dual antiplatelet therapy (DAPT) (68.9vs85%, p= 0.005). After a median follow-up time of 11.1 months, major cardio/cerebrovascular event-free survival [MACCE, including cardiovascular death, MI, TIA and stroke, target-vessel revascularization (TVR) and major arterial ischemic events] was significantly shorter (9.0vs11.2 months, p= 0.02; HR 3.2, 2.4-8.4) in PAD patients and net adverse cardiovascular events (NACE = MACCE plus major hemorrhages) were significantly more frequent (19.1%vs10.5%, p = 0.049). CONCLUSIONS: PAD identifies a subgroup of ACS patients at significantly increased cardiovascular risk, but these patients tend to be undertreated. Patients admitted for ACS should be screened for PAD and optimal medical therapy at discharge should be implemented.

The American College of Chest Physician score to assess the risk of bleeding during anticoagulation in patients with venous thromboembolism.

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.

Low drug levels and thrombotic complications in high-risk atrial fibrillation patients treated with direct oral anticoagulants.

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 CHA2 DS2 -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 CHA2 DS2 -VASc score. Larger studies are warranted to confirm these preliminary observations.

Comparison of five specific assays for determination of dabigatran plasma concentrations in patients enrolled in the START-Laboratory Register.

INTRODUCTION: Several specific assays are commercially available to determine dabigatran anticoagulant activity. Aims of this multicenter and multiplatform study were to compare five methods for dabigatran measurement and investigate their performances in the low concentration range. METHODS: Dabigatran levels were analyzed in 295 plasma samples from patients enrolled in the START-Laboratory Register by the following methods using dedicated calibrators and controls: STA-ECA II (Diagnostica Stago), standard and low range Hemoclot Thrombin Inhibitors (Hyphen BioMed), Direct Thrombin Inhibitor Assay (Instrumentation Laboratory), Direct Thrombin Inhibitor Assay (Siemens), Technoclot DTI (Technoclone). RESULTS: Methods showed variable agreement with the Hemoclot Thrombin Inhibitors assay used as reference test, with modest under- or overestimations (Bland-Altman bias from -17.3 to 4.0 ng/mL). Limits of detection and quantification varied depending on the assay (4-52 and 7-82 ng/mL, respectively). Between-run precision and accuracy were good for all methods for both quality control levels. Assay's repeatability assessed at very low dabigatran concentrations (from 10 to 60 ng/mL) was also acceptable, variability generally increased at lower drug levels. CONCLUSION: The five dabigatran-specific assays evaluated in this study provided reliable assessment of dabigatran plasma levels, although showing different performances.

External validation of the DASH prediction rule: a retrospective cohort study.

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.

Ultrasound Characteristics of Calf Deep Vein Thrombosis and Residual Vein Obstruction After Low Molecular Weight Heparin Treatment.

OBJECTIVE/BACKGROUND: Calf deep vein thrombosis (CDVT) is frequently found in symptomatic outpatients, but CDVT ultrasound diagnostic criteria are still debated. It has been proposed that only clots with ≥5 mm maximum diameter can be considered as CDVT. AIMS: To assess clot diameters and characteristics of CDVT, and to assess the recanalization rate of CDVT after anticoagulant treatment. METHODS: In a prospective, multicenter cohort study symptomatic outpatients in whom CDVT was diagnosed by ultrasound were enrolled. Posterior tibial, fibular, medial and lateral gastrocnemius, and soleal veins were compressed transversally over their entire length. Clot diameter was measured during maximum compression and ultrasound was repeated after 6 weeks of low molecular weight heparin treatment. RESULTS: In 172 patients (age 70 ± 1 y, male 32%) CDVT was detected in 132 (76.7%) muscle veins only, and in 24 (14%) axial veins only, while 16 (9.3%) patients had both muscular and axial CDVT. A total of 212 clots were found with a diameter of 5.8 ± 1.8 mm (IQR 4.5-6.8 mm) with the 10th percentile being ≥3.5 mm. A cut off value of ≥5 mm had a sensitivity of 0.76 (95% CI 0.69-0.82), whereas a value of ≥3.5 mm had a sensitivity of 0.94 (95% CI 0.89-0.97). Recanalization (i.e. residual vein obstruction ≤2 mm) was found in 51% of patients and the recanalization rate was not correlated with clot diameter at enrolment (rho -0.128 p = 0.93) or with type of CDVT (axial vs. muscular thrombosis). Patients with significantly reduced mobility had lower probability of CDVT recanalization. CONCLUSION: A clot diameter ≥5 mm is found in only 76% of CDVT patients and a clot diameter ≥3.5 mm may be more appropriate as a threshold for CDVT. After 6 weeks of anticoagulant treatment, half of CDVT patients had recanalization and recanalization was not correlated with clot characteristics at enrolment, but with mobility of the patients.

Poor comparability of coagulation screening test with specific measurement in patients receiving direct oral anticoagulants: results from a multicenter/multiplatform study.

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.

OC-15 - Risk factors for cancer development after idiopathic venous thromboembolism.

INTRODUCTION: Idiopathic venous thromboembolism (VTE) is associated with the risk of cancer but the risk factors for cancer development in such patients are still uncertain. AIM: To assess risk factors for the development of cancer after a standard course of anticoagulation in patients with first episode of idiopathic VTE. MATERIALS AND METHODS: Subjects were enrolled in the three large prospective multicentre studies: PROLONG (NEJM 2006) PROLONG II (Blood 2010) and DULCIS (Blood 2014). Women whose index event was hormone related were excluded from the analysis. The development of cancer was recorded during a 2-year follow-up. RESULTS: 1,805 patients were enrolled (M/F: 510/453), mean age: 62, median: 67; range:18-87 years). Cancer developed in 55 patients (3% ; 1.7% pt-years) of whom 15 (2.0%; 1.1% pt-years) had PE with or without DVT and 40 (3.8%; 2.1% pt-years) had DVT without PE (p=0.03). The development of cancer was associated with DVT without PE (HR:1.8; 95% CI: 1.1-3.3) and age >65 (HR: 2.5; 95%: 1.3-4.9). Among patients with DVT, with or without PE, the development of cancer was associated with the presence of residual vein obstruction>4mm (RVO) at compression ultrasound (HR: 1.8, 95% CI: 1.1-3.3) and age>65 (HR: 2.8; 95% CI: 1.3-6.2). CONCLUSIONS: Age>65 years, DVT without PE and the presence of RVO are significantly associated with the risk of developing cancer after a first episode of idiopathic VTE over a two-year follow-up.

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

INTRODUCTION: 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). METHODS: Commercial D-dimer assays, evaluated according to predetermined cutoff levels for each assay, specific for age (lower in subjects <70 years) and gender (lower in males), were used in the recent DULCIS study. The present analysis compared the results obtained in the DULCIS with those that might have been had using the following different cutoff criteria: traditional cutoff for VTE exclusion, higher levels in subjects aged ≥60 years, or age multiplied by 10. RESULTS: In young subjects, the DULCIS low cutoff levels resulted in half the recurrent events that would have occurred using the other criteria. In elderly patients, the DULCIS results were similar to those calculated for the two age-adjusted criteria. The adoption of traditional VTE exclusion criteria would have led to positive results in the large majority of elderly subjects, without a significant reduction in the rate of recurrent event. CONCLUSION: The results confirm the usefulness of the cutoff levels used in DULCIS.

Risk of recurrence after a first unprovoked venous thromboembolism: external validation of the Vienna Prediction Model with pooled individual patient data.

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.

D-dimer use for deep venous thrombosis exclusion in elderly patients: a comparative analysis of three different approaches to establish cut-off values for an assay with results expressed in D-dimer units.

INTRODUCTION: The use of adapted cut-off values in the elderly, combined with clinical probability (PTP), increases the proportion of patients in whom venous thromboembolism (VTE) can be safely excluded, compared with the conventional cut-off value of 500 µg/L fibrinogen equivalent units (FEU). We evaluated the clinical performance of three different approaches to establish cut-off values for a D-dimer assay whose results are expressed in D-dimer units (D-DU). METHODS: HemosIL D-dimer HS assay (Instrumentation Laboratory) was performed in 279 consecutive outpatients with suspected deep venous thrombosis (DVT) and nonhigh PTP. RESULTS: Considering patients >60 years, the number of negative D-dimer results increased using the modified (376 ng/mL if ≥60 years) and the age-adjusted cut-off (age years × 5 ng/mL if >50 years) compared to the conventional one (230 ng/mL for all patients; 54.6%, 58.2%, and 25.0%, respectively), with no false-negative results. The higher increase was observed in patients >80 years (43.9%, 56.1%, and 8.8%, respectively). CONCLUSION: For the HemosIL D-dimer HS, the use of specific cut-off values in older subjects with suspected DVT and nonhigh PTP increases the number of patients in whom DVT can be safely excluded.

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.

The predictive ability of bleeding risk stratification models in very old patients on vitamin K antagonist treatment for venous thromboembolism: results of the prospective collaborative EPICA study.

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.

II Italian intersociety consensus statement on antithrombotic prophylaxis in orthopaedics and traumatology: arthroscopy, traumatology, leg immobilization, minor orthopaedic procedures and spine surgery.

Pharmacological prophylaxis for preventing venous thromboembolism (VTE) is a worldwide established procedure in hip and knee replacement surgery, as well as in the treatment of femoral neck fractures, but few data exist in other fields of orthopaedics and traumatology. Thus, no guidelines or recommendations are available in the literature except for a limited number of weak statements about knee arthroscopy and lower limb fractures. In any case, none of them are a multidisciplinary effort as the one here presented. The Italian Society for Studies on Haemostasis and Thrombosis (SISET), the Italian Society of Orthopaedics and Traumatology (SIOT), the Association of Orthopaedic Traumatology of Italian Hospitals (OTODI), together with the Italian Society of Anesthesia, Analgesia, Resuscitation and Intensive Care (SIAARTI) and the Italian Society of General Medicine (SIMG) have set down easy and quick suggestions for VTE prophylaxis in a number of surgical conditions for which only scarce evidence is available. This inter-society consensus statement aims at simplifying the approach to VTE prophylaxis in the single patient with the goal to improve its clinical application.

The Wells rule and D-dimer for the diagnosis of isolated distal deep vein thrombosis.

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.

Phase III studies on novel oral anticoagulants for stroke prevention in atrial fibrillation: a look beyond the excellent results.

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.