Michael R Lassen

Glostrup Hospital, København, Capital Region, Denmark

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Publications (52)723.59 Total impact

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    ABSTRACT: Aim: To analyze concomitant drug use and its association with outcome in patients (N=17 701) receiving rivaroxaban or standard of care (SOC) for the prevention of venous thromboembolism after major orthopaedic surgery in the non-interventional, phase IV XAMOS study. Methods: Concomitant drug use was at the discretion of the treating physician. Prespecified co-medications of interest were cytochrome P450 (CYP) 3A4/P-glycoprotein inhibitors/inducers, platelet aggregation inhibitors (PAIs) and non-steroidal anti-inflammatory drugs (NSAIDs). Crude event incidences were compared between rivaroxaban and SOC groups. Results: CYP3A4/P-glycoprotein inhibitor/inducer use was infrequent, in contrast to PAI (~7%) and NSAID (~52%) use. Rivaroxaban was associated with a lower incidence of overall symptomatic thromboembolic events compared with SOC regardless of co-medication use. In both treatment groups, PAI users, with higher age and prevalence of cardiovascular co-morbidities, had similar higher (>7-fold) incidences of symptomatic arterial but not venous thromboembolic events compared with non-users. NSAID use had no influence on thromboembolic events. However, odds ratios (ORs) for major bleeding events (European Medicines Agency definition) were higher in NSAID users compared with non-users in rivaroxaban (OR=1.50; 95% confidence interval [CI] 1.06, 2.13) and SOC (OR=1.70; CI 1.16, 2.49) groups. In PAI users ORs for major bleeding events were not different compared with non-users in both the rivaroxaban (OR=1.49; CI 0.84, 2.65) and SOC (OR=1.46; CI 0.82, 2.62) groups. Conclusions: Use of NSAIDs in XAMOS was frequent and associated with higher bleeding events in patients receiving rivaroxaban or SOC, although the benefit-risk profile of rivaroxaban compared with SOC was maintained. This article is protected by copyright. All rights reserved.
    No preview · Article · Nov 2015 · British Journal of Clinical Pharmacology
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    ABSTRACT: This study was undertaken to provide evidence for the mechanism of venous thromboembolism (VTE) in healthy patients with minor lower limb injury (fracture; Achilles tendon rupture) that was medically managed with plaster cast/brace immobilization. The Plaster Cast clinical trial provided a unique opportunity to identify the natural history of VTE using placebo-controlled patients (n = 183) with validation of the mechanism using the low-molecular-weight heparin (LMWH; reviparin)-treated patients (n = 182). Confirmed VTE in this population was associated with a burst of tissue factor release (and a minor fibrinolytic deficit) leading to thrombin generation that was sustained at least 5 weeks, greater with fractures than with soft-tissue injuries and greater with surgery than with conservative treatment. The root cause likely involves platelet/leukocyte activation (inflammation) rather than endothelial cell injury. Thromboprophylaxis with a low dose of LMWH reduced thrombin generation, with patients undergoing surgery benefitting the most.
    No preview · Article · Aug 2014 · Clinical and Applied Thrombosis/Hemostasis
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    ABSTRACT: Introduction We have recently reported that increased levels of urine prothrombin fragment 1 + 2 reflected radiologically verified deep vein thrombosis. In this study we evaluated whether urine prothrombin fragment 1 + 2 was associated with pulmonary embolism in non-selected patients. Materials and methods Patients with clinical suspected pulmonary embolism were interviewed on comorbidities and medications. Urine was collected from each patient before radiological examination and snap frozen until analysed on urine prothrombin fragment 1 + 2 with an ELISA kit. Imaging of the pulmonary arteries were conducted with contrast enhanced computer tomography. Results Pulmonary embolism was diagnosed in 44/197 patients. Non-significantly higher urine prothrombin fragment 1 + 2 levels were found in non-selected patients with pulmonary embolism vs. those without (p = 0.324). Significantly higher urine prothrombin fragment 1 + 2 levels were found in the pulmonary embolism positive patients without comorbidities (n = 13) compared to the control group (n = 28) (p = 0.009). The calculated sensitivity, specificity and negative predictive value using the lowest detectable urine prothrombin fragment 1 + 2 level was 82%, 34% and 87%, respectively. Conclusions There was no significant urine prothrombin fragment 1 + 2 level difference in patients with and without pulmonary embolism. In non-comorbide pulmonary embolism positive patients the urine prothrombin fragment 1 + 2 levels were significantly higher compared to the control group. The negative predictive value found in this study indicates that uF1 + 2 has the potential to identify patients with a low risk of PE.
    Full-text · Article · Jul 2014 · Thrombosis Research

  • No preview · Article · Jun 2014 · American Journal of Hematology
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    ABSTRACT: To compare efficacy and safety of thromboprophylaxis with semuloparin started postoperatively versus enoxaparin started preoperatively in major abdominal surgery. Venous thromboembolism is an important complication following major abdominal surgery. Semuloparin is a novel ultra-low-molecular-weight heparin with high antifactor Xa and minimal antifactor IIa activity. In this double-blind noninferiority trial, adult patients undergoing major abdominal or pelvic operation under general anesthesia lasting more than 45 minutes were assigned to either daily enoxaparin 40 mg commenced preoperatively or daily semuloparin 20 mg commenced postoperatively, for 7 to 10 days. Patients underwent bilateral leg venography between 7 and 11 days postsurgery. The primary efficacy end point was the composite of any deep vein thrombosis, nonfatal pulmonary embolism, or all-cause death. The primary safety outcome was bleeding. Both were independently adjudicated. In total, 4413 patients were randomized; 3030 (1499 in the enoxaparin and 1531 in the semuloparin groups) were evaluable for the primary efficacy end point, which occurred in 97 patients (6.3%) in the semuloparin group and 82 patients (5.5%) in the enoxaparin group [odds ratio (OR) = 1.16, 95% confidence interval (CI): 0.84-1.59]. On the basis of a noninferiority margin of 1.25, postoperative semuloparin did not demonstrate noninferiority to preoperative enoxaparin. Major bleeding occurred in 63 of 2175 patients (2.9%) in the semuloparin group and 98 of 2177 patients (4.5%) in the enoxaparin group (OR = 0.63, 95% CI: 0.46-0.87). Semuloparin commenced postoperatively did not demonstrate noninferiority to enoxaparin initiated preoperatively for thromboprophylaxis after major abdominal surgery. Study registered with clinicaltrials.gov: NCT00679588.
    No preview · Article · Dec 2013 · Annals of surgery
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    ABSTRACT: Introduction: Disturbances in cytokine networks are believed to be associated with increased risk of adverse pregnancy complications. Methods: Plasma samples collected from pregnant women with preterm deliveries, high-risk pregnancy complications including postpartum hemorrhage, hypertensive disorders, and multiple gestations, and normal pregnancies were analyzed at different periods throughout gestation and postpartum. Interleukin (IL) 1β , IL-6, IL-8, IL-10, tumor necrosis factor α, and antiprotein Z antibody levels were measured by enzyme-linked immunosorbent assay. Results: The IL-6 levels in preterm delivery patients were elevated during pregnancy with statistically significant differences observed at 21 to 32 weeks (P < .01) and 33+ weeks (P < .001). The IL-10 levels were increased in normal pregnancy at all time points compared to the other patient groups (P < .05). The TNF-α levels were elevated in the high-risk pregnancy group versus normal controls (P < .001 at <21 weeks and P < .05 at 21-32 weeks). Conclusion: Analysis of the maternal plasma for elevated IL-6 and reduced IL-10 levels may be of value in the early prediction of pregnancy complications.
    No preview · Article · Jul 2013 · Clinical and Applied Thrombosis/Hemostasis
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    ABSTRACT: Introduction: The appearance of prothrombin fragment 1 + 2 (F1 + 2) in urine has been associated with postoperative hypercoagulability and thromboembolism. We wanted to assess if F1 + 2 was released in urine (uF1 + 2) in patients with procoagulant disorders, and if higher levels were found in patients with radiological verified deep vein thrombosis (DVT). Materials and methods: Consecutive patients were interviewed on comorbidities and medications. An unselected total cohort (n = 534) and a control cohort (n = 177) were analysed. A urine sample (10 ml) was collected and snap frozen before levels of uF1 + 2 were measured with an ELISA kit. Visualisation of DVT was done with compression ultrasound, supplied with venography when feasible. All patients were followed up for 3-6 months. Results: DVT was diagnosed in 108/534 patients. Statistical significant higher uF1 + 2 levels were found in patients with DVT (p < 0.001), in DVT positive patients with ongoing malignancy (p = 0.034) and in pregnant women compared to the control cohort (p < 0.001). Non-significant increased urine concentrations were found in DVT positive vs. DVT negative patients with infections and traumas. Conclusions: Levels of uF1 + 2 was associated with DVT both in the total cohort and in the control cohort as well as in most patients with coexisting conditions.
    Full-text · Article · May 2013 · Thrombosis Research
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    ABSTRACT: Venous thromboembolism is a frequent and potentially life-threatening complication of orthopedic surgery. Rivaroxaban is an oral direct factor Xa inhibitor, which was shown to be effective for the prevention of venous thromboembolism after elective hip and knee arthroplasty in the RECORD study program. Rivaroxaban has the potential to overcome the limitations of the current standards of care in the prevention of venous thromboembolism. XAMOS (Xarelto(®) in the prophylaxis of post-surgical venous thromboembolism after elective major orthopedic surgery of hip or knee) is an international, noninterventional, parallel-group study to gain insight into the safety (major bleeding, side effects) and effectiveness (prevention of symptomatic thromboembolic events) of rivaroxaban in daily clinical practice. XAMOS will follow 15,000 patients after major orthopedic surgery in approximately 200 centers worldwide, with about 7500 patients receiving rivaroxaban and about 7500 standard of care. XAMOS will supplement the clinical data obtained in the Phase III RECORD 1, 2, 3, and 4 trials in which rivaroxaban was shown to be superior for the primary efficacy endpoints, and with a safety profile similar to that of enoxaparin after hip or knee replacement surgery. XAMOS was started in 2009 and will complete recruitment and follow-up in 2011.
    Full-text · Article · Jun 2012 · Vascular Health and Risk Management
  • M R Lassen
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    ABSTRACT: Apixaban is an anticoagulant drug that acts by directly inhibiting coagulation factor Xa. Unlike low-molecular-weight heparins and fondaparinux, apixaban can be taken orally; in contrast to vitamin K antagonists, its clinical use does not require dose adjustments according to coagulation monitoring. Apixaban in a regimen of 2.5 mg twice daily has been approved in Europe for the prevention of venous thromboembolism in patients undergoing elective total hip or knee replacement. This approval was based on the results of two large phase III trials showing that, compared to the European approved regimen of enoxaparin for total hip and knee replacement (i.e., 40 mg once daily starting preoperatively), apixaban 2.5 mg twice daily initiated 12-24 hours after wound closure was more effective in preventing venous thromboembolism, without increasing the risk of bleeding. This apixaban regimen may therefore represent a convenient alternative to conventional anticoagulant drug regimens in the prevention of venous thromboembolism in this surgical setting. However, there are several precautions that prescribers should take into account before using this drug regimen. In this article, various points are considered, notably bleeding risk and the use of this novel oral anticoagulant in special populations or in the context of neuraxial anesthesia.
    No preview · Article · Apr 2012 · Drugs of today (Barcelona, Spain: 1998)
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    ABSTRACT: Semuloparin is a novel ultra-low-molecular-weight heparin under development for venous thromboembolism (VTE) prevention in patients at increased risk, such as surgical and cancer patients. Three Phase III studies compared semuloparin and enoxaparin after major orthopedic surgery: elective knee replacement (SAVE-KNEE), elective hip replacement (SAVE-HIP1) and hip fracture surgery (SAVE-HIP2). All studies were multinational, randomized and double-blind. Semuloparin and enoxaparin were administered for 7-10 days after surgery. Mandatory bilateral venography was to be performed between days 7 and 11. The primary efficacy endpoint was a composite of any deep vein thrombosis, non-fatal pulmonary embolism or all-cause death. Safety outcomes included major bleeding, clinically relevant non-major (CRNM) bleeding, and any clinically relevant bleeding (major bleeding plus CRNM). In total, 1150, 2326 and 1003 patients were randomized in SAVE-KNEE, SAVE-HIP1 and SAVE-HIP2, respectively. In all studies, the incidences of the primary efficacy endpoint were numerically lower in the semuloparin group vs. the enoxaparin group, but the difference was statistically significant only in SAVE-HIP1. In SAVE-HIP1, clinically relevant bleeding and major bleeding were significantly lower in the semuloparin vs. the enoxaparin group. In SAVE-KNEE and SAVE-HIP2, clinically relevant bleeding tended to be higher in the semuloparin group, but rates of major bleeding were similar in the two groups. Other safety parameters were generally similar between treatment groups. Semuloparin was superior to enoxaparin for VTE prevention after hip replacement surgery, but failed to demonstrate superiority after knee replacement surgery and hip fracture surgery. Semuloparin and enoxaparin exhibited generally similar safety profiles.
    Full-text · Article · Mar 2012 · Journal of Thrombosis and Haemostasis
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    ABSTRACT: Patients receiving chemotherapy for cancer are at increased risk for venous thromboembolism. Limited data support the clinical benefit of antithrombotic prophylaxis. In this double-blind, multicenter trial, we evaluated the efficacy and safety of the ultra-low-molecular-weight heparin semuloparin for prevention of venous thromboembolism in patients receiving chemotherapy for cancer. Patients with metastatic or locally advanced solid tumors who were beginning to receive a course of chemotherapy were randomly assigned to receive subcutaneous semuloparin, 20 mg once daily, or placebo until there was a change of chemotherapy regimen. The primary efficacy outcome was the composite of any symptomatic deep-vein thrombosis, any nonfatal pulmonary embolism, and death related to venous thromboembolism. Clinically relevant bleeding (major and nonmajor) was the main safety outcome. The median treatment duration was 3.5 months. Venous thromboembolism occurred in 20 of 1608 patients (1.2%) receiving semuloparin, as compared with 55 of 1604 (3.4%) receiving placebo (hazard ratio, 0.36; 95% confidence interval [CI], 0.21 to 0.60; P<0.001), with consistent efficacy among subgroups defined according to the origin and stage of cancer and the baseline risk of venous thromboembolism. The incidence of clinically relevant bleeding was 2.8% and 2.0% in the semuloparin and placebo groups, respectively (hazard ratio, 1.40; 95% CI, 0.89 to 2.21). Major bleeding occurred in 19 of 1589 patients (1.2%) receiving semuloparin and 18 of 1583 (1.1%) receiving placebo (hazard ratio, 1.05; 95% CI, 0.55 to 1.99). Incidences of all other adverse events were similar in the two study groups. Semuloparin reduces the incidence of thromboembolic events in patients receiving chemotherapy for cancer, with no apparent increase in major bleeding. (Funded by Sanofi; ClinicalTrials.gov number, NCT00694382.).
    Full-text · Article · Feb 2012 · New England Journal of Medicine

  • No preview · Conference Paper · Jan 2012
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    ABSTRACT: Thromboembolic disease is a common complication of hip fracture in the elderly. Anticoagulants represent a standard of care in preventing postoperative thrombotic complications following surgical fixation. We asked whether levels of antibody to heparin-platelet factor 4 (PF4) complex were differentially present in unfractionated heparin (UFH) versus Enoxaparin, following hip fracture and whether one particular subtype of antibodies was more prevalent. Plasma samples from elderly patients sustaining a hip fracture treated with either enoxaparin or UFH were collected pre- and postoperatively and analyzed using enzyme-linked immunosorbent assay (ELISA) sandwich method for the prevalence of antiheparin-PF4 antibodies and later subtyped. The prevalence of antiheparin-PF4 antibodies was higher in the UFH group especially on postoperative day 7. Patients treated with UFH showed a greater prevalence of antiheparin-PF4 antibodies and a greater prevalence of immunoglobulin G (IgG) subtype. Heparin and enoxaparin are capable of generating heparin-induced thrombocytopenia (HIT) antibodies in elderly patients undergoing orthopedic surgery but perhaps not to the same extent. When comparing low-molecular-weight heparin (LMWH) with UFH, the incidence of new antiheparin-PF4 antibody production is higher in patients treated with UFH.
    No preview · Article · Nov 2011 · Clinical and Applied Thrombosis/Hemostasis
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    Lars C Borris · Morten Breindahl · Michael R Lassen · Akos F Pap
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    ABSTRACT: Prothrombin fragment 1+2 is excreted in urine (uF1+2) as a result of in vivo thrombin generation and can be a marker of coagulation status after an operative procedure. This study compared uF1+2 levels in patients with symptomatic and non-symptomatic venous thromboembolism (VTE) after total knee replacement (TKR) and in event-free sex- and age-matched controls. Significantly higher median uF1+2 levels were seen in the VTE patients on days 1, 3, and the day of venography (mostly day 7) after TKR compared with controls. The uF1+2 levels tended to be high in some patients with symptomatic VTE; however, the discriminatory efficacy of the test could not be evaluated. In conclusion, this study showed that patients with VTE tend to have significantly higher uF1+2 levels compared with patients without events between days 1 and 7 after TKR surgery. Measurement of uF1+2 could provide a simple, non-invasive clinical test to identify patients at risk of VTE.
    Full-text · Article · May 2011
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    ABSTRACT: Four phase III studies compared oral rivaroxaban with subcutaneous enoxaparin for the prevention of venous thromboembolism (VTE) after total hip or knee arthroplasty (THA or TKA). A pooled analysis of these studies compared the effect of rivaroxaban with enoxaparin on symptomatic VTE plus all-cause mortality and bleeding events, and determined whether these effects were consistent in patient subgroups. Patients (N=12,729) aged ≥18 years and scheduled for elective THA or TKA received rivaroxaban 10 mg once daily or enoxaparin 40 mg once daily or 30 mg every 12 hours. The composite of symptomatic VTE and all-cause mortality, the prespecified primary efficacy endpoint and adjudicated bleeding events were analysed in the day 12± 2 active treatment pool. Subgroup analyses of these outcomes were performed over the total treatment period. In the day 12± 2 pool, the primary efficacy endpoint occurred in 29/6,183 patients receiving rivaroxaban (0.5%) versus 60/6,200 patients receiving enoxaparin (1.0%; p=0.001). Major bleeding occurred in 21 (0.3%) versus 13(0.2%) patients, p=0.23; major plus non-major clinically relevant bleeding in 176(2.8%) versus 152 (2.5%) patients, p=0.19; and any bleeding in 409 (6.6%) versus 384 (6.2%) patients, p=0.38, respectively. The reduction of symptomatic VTE plus all-cause mortality was consistent across prespecified subgroups (age, gender, body weight, creatinine clearance) in the total treatment period. Compared with enoxaparin regimens, rivaroxaban reduces the composite of symptomatic VTE and all-cause mortality after elective THA or TKA, with a small increase in bleeding, no signs of compromised liver safety and fewer serious adverse events.
    No preview · Article · Dec 2010 · Thrombosis and Haemostasis
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    ABSTRACT: There are various regimens for thromboprophylaxis after hip replacement. Low-molecular-weight heparins such as enoxaparin predominantly inhibit factor Xa but also inhibit thrombin to some degree. Orally active, specific factor Xa inhibitors such as apixaban may provide effective thromboprophylaxis with a lower risk of bleeding and improved ease of use. In this double-blind, double-dummy study, we randomly assigned 5407 patients undergoing total hip replacement to receive apixaban at a dose of 2.5 mg orally twice daily or enoxaparin at a dose of 40 mg subcutaneously every 24 hours. Apixaban therapy was initiated 12 to 24 hours after closure of the surgical wound; enoxaparin therapy was initiated 12 hours before surgery. Prophylaxis was continued for 35 days after surgery, followed by bilateral venographic studies. The primary efficacy outcome was the composite of asymptomatic or symptomatic deep-vein thrombosis, nonfatal pulmonary embolism, or death from any cause during the treatment period. Patients were followed for an additional 60 days after the last intended dose of study medication. A total of 1949 patients in the apixaban group (72.0%) and 1917 patients in the enoxaparin group (71.0%) could be evaluated for the primary efficacy analysis. The primary efficacy outcome occurred in 27 patients in the apixaban group (1.4%) and in 74 patients in the enoxaparin group (3.9%) (relative risk with apixaban, 0.36; 95% confidence interval [CI], 0.22 to 0.54; P<0.001 for both noninferiority and superiority; absolute risk reduction, 2.5 percentage points; 95% CI, 1.5 to 3.5). The composite outcome of major and clinically relevant nonmajor bleeding occurred in 129 of 2673 patients assigned to apixaban (4.8%) and 134 of 2659 assigned to enoxaparin (5.0%) (absolute difference in risk, -0.2 percentage points; 95% CI, -1.4 to 1.0). Among patients undergoing hip replacement, thromboprophylaxis with apixaban, as compared with enoxaparin, was associated with lower rates of venous thromboembolism, without increased bleeding. (Funded by Bristol-Myers Squibb and Pfizer; ClinicalTrials.gov number, NCT00423319.).
    Full-text · Article · Dec 2010 · New England Journal of Medicine
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    ABSTRACT: Low-molecular-weight heparins such as enoxaparin are preferred for prevention of venous thromboembolism after major joint replacement. Apixaban, an orally active factor Xa inhibitor, might be as effective, have lower bleeding risk, and be easier to use than is enoxaparin. We assessed efficacy and safety of these drugs after elective total knee replacement. In ADVANCE-2, a multicentre, randomised, double-blind phase 3 study, patients undergoing elective unilateral or bilateral total knee replacement were randomly allocated through an interactive central telephone system to receive oral apixaban 2.5 mg twice daily (n=1528) or subcutaneous enoxaparin 40 mg once daily (1529). The randomisation schedule was generated by the Bristol-Myers Squibb randomisation centre and stratified by study site and by unilateral or bilateral surgery with a block size of four. Investigators, patients, statisticians, adjudicators, and steering committee were masked to allocation. Apixaban was started 12-24 h after wound closure and enoxaparin 12 h before surgery; both drugs were continued for 10-14 days, when bilateral ascending venography was scheduled. Primary outcome was the composite of asymptomatic and symptomatic deep vein thrombosis, non-fatal pulmonary embolism, and all-cause death during treatment. The statistical plan required non-inferiority of apixaban before testing for superiority; analysis was by intention to treat for non-inferiority testing. The study is registered at ClinicalTrials.gov, number NCT00452530. 1973 of 3057 patients allocated to treatment (1528 apixaban, 1529 enoxaparin) were eligible for primary efficacy analysis. The primary outcome was reported in 147 (15%) of 976 apixaban patients and 243 (24%) of 997 enoxaparin patients (relative risk 0.62 [95% CI 0.51-0.74]; p<0.0001; absolute risk reduction 9.3% [5.8-12.7]). Major or clinically relevant non-major bleeding occurred in 53 (4%) of 1501 patients receiving apixaban and 72 (5%) of 1508 treated with enoxaparin (p=0.09). Apixaban 2.5 mg twice daily, starting on the morning after total knee replacement, offers a convenient and more effective orally administered alternative to 40 mg per day enoxaparin, without increased bleeding. Bristol-Myers Squibb; Pfizer.
    No preview · Article · Mar 2010 · The Lancet
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    ABSTRACT: Hip fracture is common in the elderly patients with associated high risk of venous thromboembolic complications. Pathogenic activation results in the generation of various surrogate markers in plasma. This study is designed to identify unique biomarkers in elderly patients with hip fracture using protein chip array enzyme-linked immunosorbent assay (ELISA) methods. Plasma from a randomized hip fracture study (PK-532; n = 341) treated with either enoxaparin (40 mg once daily) or unfractionated heparin (UFH; 5000 IU twice daily) were collected prior to and at 1, 3, 5, and 7 days. A total of 52 samples were analyzed using proteomic surface-enhanced laser desorption/ ionization-time of flight (SELDI-TOF) mass spectrometry to identify unique biomarkers in the molecular weight range of 0 to 150 kd. Twenty-nine healthy volunteer's and pooled plasma from total hip replacement/total knee replacement patients with a unique biomarker at 11.9 kd were used as quality controls. In the 29 healthy individuals, the biomarker profile did not reveal the presence of any unique peak in comparison to the reference normal human plasma (NHP). Plasma obtained prior to surgery exhibits unique biomarkers in 4 of 52 (7.6%) of the samples. On day 1 postoperatively, 41 of 51 (80.3%) showed a distinct peak at 11.9 kd. On day 3, 43 of 49 (87.8%) patients showed the presence of this biomarker most often at its strongest intensity. In all, 22 of 44 (50%) showed this biomarker on day 5 and 4 of 23 (17.9%) on day 7. C-reactive protein (CRP), tumor necrosis factor alpha (TNF-alpha), and serum amyloid A were also increased after surgery. Tissue factor pathway inhibitor (TFPI) antigen levels were increased due to the treatment modalities.
    No preview · Article · Dec 2009 · Clinical and Applied Thrombosis/Hemostasis

  • No preview · Article · Oct 2009 · Chest
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    ABSTRACT: The optimal strategy for thromboprophylaxis after major joint replacement has not been established. Low-molecular-weight heparins such as enoxaparin predominantly target factor Xa but to some extent also inhibit thrombin. Apixaban, a specific factor Xa inhibitor, may provide effective thromboprophylaxis with a low risk of bleeding and improved ease of use. In a double-blind, double-dummy study, we randomly assigned patients undergoing total knee replacement to receive 2.5 mg of apixaban orally twice daily or 30 mg of enoxaparin subcutaneously every 12 hours. Both medications were started 12 to 24 hours after surgery and continued for 10 to 14 days. Bilateral venography was then performed. The primary efficacy outcome was a composite of asymptomatic and symptomatic deep-vein thrombosis, nonfatal pulmonary embolism, and death from any cause during treatment. Patients were followed for 60 days after anticoagulation therapy was stopped. A total of 3195 patients underwent randomization, with 1599 assigned to the apixaban group and 1596 to the enoxaparin group; 908 subjects were not eligible for the efficacy analysis. The overall rate of primary events was much lower than anticipated. The rate of the primary efficacy outcome was 9.0% with apixaban as compared with 8.8% with enoxaparin (relative risk, 1.02; 95% confidence interval, 0.78 to 1.32). The composite incidence of major bleeding and clinically relevant nonmajor bleeding was 2.9% with apixaban and 4.3% with enoxaparin (P=0.03). As compared with enoxaparin for efficacy of thromboprophylaxis after knee replacement, apixaban did not meet the prespecified statistical criteria for noninferiority, but its use was associated with lower rates of clinically relevant bleeding and it had a similar adverse-event profile. (ClinicalTrials.gov number, NCT00371683.)
    No preview · Article · Sep 2009 · New England Journal of Medicine

Publication Stats

9k Citations
723.59 Total Impact Points


  • 2012-2015
    • Glostrup Hospital
      København, Capital Region, Denmark
  • 2007-2014
    • IT University of Copenhagen
      København, Capital Region, Denmark
  • 2004-2013
    • Copenhagen University Hospital
      København, Capital Region, Denmark
  • 2008-2011
    • Nordsjællands Hospital
      Hillerød, Capital Region, Denmark
  • 2009
    • Aalborg University Hospital
      Ålborg, North Denmark, Denmark
  • 2005
    • University of Greifswald
      Griefswald, Mecklenburg-Vorpommern, Germany
  • 2002-2003
    • Hillerød Hospital
      Hillerød, Capital Region, Denmark
    • Sahlgrenska University Hospital
      Goeteborg, Västra Götaland, Sweden
    • Beth Israel Deaconess Medical Center
      • Department of Medicine
      Boston, MA, United States
    • Hamilton Health Sciences
      Hamilton, Ontario, Canada