Sustained prothrombotic profile after hip replacement surgery: the influence of prolonged prophylaxis with dalteparin

Summary.  In a randomized trial on the effect of dalteparin for 5 weeks after HRS we evaluated hemostatic variables in plasma sampled before and 1, 6 and 35 days postoperatively. In 218 patients we found that prothrombin fragment 1 + 2 (F1 + 2), thrombin–antithrombin complexes (TAT), d -dimer and fibrinogen were significantly higher on day 35 as compared with baseline values in the placebo group ( P  < 0.001 for all). The same pattern was found in the dalteparin group, but with significantly lower values for F1 + 2, TAT and d -dimer. In patients in the placebo group with venographically proven deep vein thrombosis (DVT) on day 35 (33%), significantly higher values were found for F1 + 2, TAT and d -dimer than in patients without DVT. Patients in the highest quartile of d -dimer (>2850 ng mL⁻¹) had an odds ratio for the presence of DVT of 24.0 when compared with patients in the lowest quartile (<1625 ng mL⁻¹). It is concluded that a substantial hypercoagulability is sustained until day 35 after HRS, significantly reduced with prolonged administration of dalteparin.     

Low dose heparin versus low molecular weight heparin (Kabi 2165, Fragmin®) in the prophylaxis of thromboembolic complications of abdominal oncological surgery

Eighty patients undergoing pelvic or abdominal surgery for cancer were randomized in two groups for prevention of postoperative thromboembolism: 40 patients received a 15,000 IU day-1 Calciparine prophylaxis and 40 patients a 5000 anti-Xa U/d Fragmin prophylaxis for 10 days. In the Calciparine group, two patients (5%) developed postoperative pulmonary embolism but none developed it in the Fragmin group. Two patients in the Fragmin group (5%) developed isotopic DVT, which was not confirmed by phlebography. There was no deep vein thrombosis of the lower limbs in the two groups. Important postoperative bleeding (one patient in the Calciparine group and two patients in the Fragmin group) was similar in both groups. Moderate and minor bleeding were significantly lower in the Fragmin group. Haemoglobin and haematocrit changes, total blood loss and transfusion requirements were not different in both groups. It is concluded that, over a 10-day period, one daily 5000 U Fragmin prophylaxis was as effective and safe as three daily 5000 IU Calciparine injections.     

A randomized double‐blind study of low‐molecular‐weight heparin (parnaparin) for superficial vein thrombosis: STEFLUX (Superficial ThromboEmbolism and Fluxum)

Summary. 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.     

Dose escalation of low molecular weight heparin to manage recurrent venous thromboembolic events despite systemic anticoagulation in cancer patients

Summary.  Background:  Cancer patients with venous thromboembolism (VTE) are at high risk of recurrent VTE despite standard anticoagulation. To date, very little published literature is available to guide the treatment of cancer patients with recurrent VTE. Objectives:  To evaluate the benefit and risk of low molecular weight heparin (LMWH) dose escalation in cancer patients with recurrent VTE. Patients and methods:  This was a retrospective cohort study of consecutive cancer outpatients referred for management of a symptomatic, recurrent VTE while receiving an anticoagulant. Confirmed episodes of recurrent VTE were treated with either dose escalation of LMWH in patients already anticoagulated with LMWH, or initiation of therapeutic dose LMWH in patients who were taking a vitamin K antagonist (VKA). All patients were followed for a minimum of 3 months after the index recurrent VTE unless they died during this period. Results:  Seventy cancer patients with a recurrent VTE despite ongoing anticoagulation were included. At the time of the recurrence, 67% of patients were receiving LMWH, and 33% were receiving a VKA. A total of six patients [8.6%; 95% confidence interval (CI) 4.0–17.5%] had a second recurrent VTE during the 3-month follow-up period, at an event rate of 9.9 per 100 patient-years (95% CI  2.0–17.8%). Three patients (4.3%; 95% CI  1.5–11.9%), or 4.8 per 100 patient-years (95% CI  0.0–10.3%) of follow-up, had bleeding complications. The median time between the index recurrent VTE to death was 11.4 months (range, 0–83.9 months). Conclusions:  Cancer patients with recurrent VTE have a short median survival. Escalating the dose of LMWH can be effective for treating cases that are resistant to standard, weight-adjusted doses of LMWH or a VKA.     

PRODIGE: a randomized placebo‐controlled trial of dalteparin low‐molecular‐weight heparin thromboprophylaxis in patients with newly diagnosed malignant glioma

Summary. Background and objectives: Venous thromboembolism (VTE) occurs in 20–30% of patients with malignant glioma per year of survival. We tested the efficacy of long‐term dalteparin low‐molecular‐weight heparin (LMWH) for prevention of VTE in these patients. Patients/methods: Adults with newly diagnosed malignant glioma were randomized to receive dalteparin 5000 anti‐Xa units or placebo, both subcutaneously once daily for 6 months starting within 4 weeks of surgery. Treatment continued for up to 12 months. The primary outcome was the cumulative risk of VTE over 6 months. The target sample size was 512 patients. Events were adjudicated by a committee unaware of treatment. Results: The trial began in 2002 and closed in May 2006 because of expiration of study medication. Ninety‐nine patients were randomized to LMWH and 87 to placebo. Twenty‐two patients developed VTE in the first 6 months: nine in the LMWH group and 13 in the placebo group [hazard ratio (HR) = 0.51, 95% confidence interval (CI): 0.19–1.4, P = 0.29]. At 6 months, there were three major bleeds on LMWH and none on placebo; at 12 months, 5 (5.1%) major bleeds on LMWH and 1 (1.2%) on placebo occurred (HR = 4.2, 95% CI: 0.48–36, P = 0.22). All major bleeds were intracranial and occurred while on study medication. The 12‐month mortality rates were 47.8% for LMWH and 45.4% for placebo (HR = 1.2, 95% CI: 0.73–2.0, P = 0.48). Conclusions: Trends suggesting reduced VTE and increased intracranial bleeding were seen in the LMWH thromboprophylaxis group. The role of long‐term anticoagulant thromboprophylaxis in patients with brain tumors remains uncertain.     

利伐沙班预防老年患者髋关节置换术后深静脉血栓效果观察

目的探讨行髋关节置换术老年患者应用利伐沙班预防术后深静脉血栓形成（deep vein thrombosis,DVT）的效果。方法初次行髋关节置换术老年患者145例,依据术后用药分为利伐沙班组75例与肝素组70例。利伐沙班组于术后6~8h口服利伐沙班10mg/次,1次/d;肝素组于术后12~14h腹壁皮下注射低分子肝素0.4mL/次,1次/d,2组均连续应用10d。术后第11天行彩超检查观察2组DVT形成情况,比较2组术后切口出血发生率、引流量、血小板计数、活化部分凝血酶时间（activated partial thromboplastin time,APTT）、凝血酶原时间（prothrombin time,PT）水平。结果利伐沙班组术后发生DVT 5例（6.7%）,切口出血2例（2.7%）,术后引流量（148.3±20.1）mL,血小板计数（223.0±13.1）×109/L,ATPP（35.4±7.8）s,PT（12.6±0.9）s;肝素组术后发生DVT 6例（8.6%）,切口出血3例（4.3%）,术后引流量（155.0±29.3）mL,血小板计数（219.5±12.2）×109/L,ATPP（36.7±8.9）s,PT（12.4±1.1）s,2组比较差异均无统计学意义（P〉0.05）。结论利伐沙班预防老年患者髋关节置换术后DVT形成的效果与低分子肝素相当,但利伐沙班可口服给药,患者依从性高。     

Fixed-dose low-molecular-weight heparin for secondary prevention of venous thromboembolism in patients with disseminated cancer: a prospective cohort study.

INTRODUCTION: Secondary prevention of venous thromboembolism (VTE) with vitamin K antagonists is often problematic in patients with cancer. We prospectively evaluated the effectiveness and safety of long-term subcutaneous dalteparin in a series of consecutive patients with symptomatic VTE and metastatic cancer. PATIENTS AND METHODS : The study included 203 patients, aged 36-96 years. The initial treatment consisted of a 7-day course of subcutaneous dalteparin according to body weight. Then, patients received a fixed dose of 10 000 IU dalteparin once daily for at least 3 months. In patients developing transient thrombocytopenia the dose was reduced to 5000 IU daily while the platelet count remained <50,000; and to 2500 IU daily while it remained <10 000. Patients undergoing any surgical intervention during the study were put on 5000 IU daily during the first 4 days, switching thereafter to 10,000 IU. Patients undergoing any other invasive procedure (i.e. biopsies, punctures) received a 5000 IU dose the same day, instead of 10 000 IU. RESULTS: Eleven patients (5.4%) developed major bleeding complications (6 fatal) during the 3-month study period, and 18 patients (8.9%) developed VTE recurrences (2 patients died). There were no higher complication rates in patients with either liver or brain metastases, nor during thrombocytopenia, surgery or invasive procedures. CONCLUSIONS: Fixed dose 10,000 IU subcutaneous dalteparin once daily for 3 months was not associated with more complications in patients with liver or brain metastases. The dose adjustment for patients with thrombocytopenia, surgery or invasive procedures was safe too.     

The safety of dosing dalteparin based on actual body weight for the treatment of acute venous thromboembolism in obese patients.

Data evaluating the safety of using weight-based low-molecular-weight heparin in the treatment of obese patients with acute venous thromboembolism are limited. The product monograph of dalteparin suggests the maximum dose should be limited to 18,000 U subcutaneously once daily. There are no specific data regarding the risk of recurrence or bleeding in patients given dalteparin in a weight-based dose of 200 IU kg(-1). We report a retrospective chart review of 193 obese patients who weighed more than 90 kg and who received dalteparin at or near to 200 IU kg(-1) actual body weight for 5-7 days for acute venous thromboembolism with 90 day follow-up information. Of the patients, 77% had idiopathic venous thromboembolism, 16% had an underlying malignancy, and 7% had a transient risk factor. Warfarin was initiated within 2 days with a target International Normalized Ratio range of 2.0-3.0. All patients were followed for 12 weeks post diagnosis. Only two patients had a major hemorrhage, 4 and 8 weeks from diagnosis. This study supports the safety of dosing dalteparin based on actual body weight in obese patients.     

A randomized,double‐blind study of certoparin vs. unfractionated heparin to prevent venous thromboembolic events in acutely ill,non‐surgical patients: CERTIFY Study

Summary. Background: In medically ill patients, no contemporary double‐blind head‐to‐head evaluation of low molecular weight heparin vs. unfractionated heparin (UFH) for the prevention of venous thromboembolic events is available. Objectives: To compare the efficacy and safety of certoparin with those of UFH. Patients/Methods: In this double‐blind, randomized, controlled trial, acutely ill, non‐surgical patients aged ≥ 70 years were randomized to certoparin (3000 U of anti‐factor Xa once daily) or to UFH (5000 IU t.i.d.). The primary endpoint was the composite of proximal deep vein thrombosis as assessed by bilateral compression ultrasonography, symptomatic non‐fatal pulmonary embolism and venous thromboembolism‐related death, and was assessed by a blinded central adjudication committee. Non‐inferiority margins were set at 1.8 for the odds ratio (OR) and 3.45% for the absolute difference. Results: Three thousand two hundred and thirty‐nine patients aged 78.8 ± 6.3 years were treated for 9.1 ± 3.4 days. The incidence of the primary endpoint was 3.94% in the certoparin group and 4.52% in the UFH group, with a difference in proportions of ? 0.59% [95% confidence interval (CI) ?2.09 to 0.92; P < 0.0001 for non‐inferiority], and an OR of 0.87 (95% CI 0.60–1.26; P = 0.0001 for non‐inferiority). Major bleeding occurred in 0.43% of certoparin‐treated patients and 0.62% of UFH‐treated patients (OR 0.69; 95% CI 0.26–1.83). Any bleeding occurred at 3.20% in certoparin‐treated patients vs. 4.58% in UFH‐treated patients (OR 0.69; 95% CI 0.48–0.99; P < 0.05), and 5.73% of certoparin‐treated patients and 6.63% of UFH‐treated patients experienced serious adverse events. All‐cause mortality was 1.27% in certoparin‐treated patients and 1.36% in UFH‐treated patients. Conclusions: In acutely ill, non‐surgical elderly patients, thromboprophylaxis with certoparin (3000 U of anti‐FXa once daily) was non‐inferior to 5000 IU of UFH t.i.d., with a favorable safety profile.     

Current perspectives on the treatment of venous thromboembolism: need for effective, safe and convenient new antithrombotic drugs

Treatment of venous thromboembolism (VTE) has evolved significantly over the last decade. Low-molecular-weight heparins have largely replaced unfractionated heparin in the treatment of deep-vein thrombosis (DVT) but the majority of patients with pulmonary embolism (PE) continue to be treated with unfractionated heparin. Fondaparinux is the first synthetic selective inhibitor of factor Xa. It has recently been proved to be more effective than, and as safe as, a low-molecular-weight heparin for the prevention of VTE after major orthopaedic surgery. The two large randomised MATISSE trials demonstrated that fondaparinux was at least as effective and as safe as previous reference heparin therapies in the treatment of VTE. Fondaparinux should further simplify the treatment of this frequent disease since a single once-daily fixed dosage regimen may effectively and safely treat both DVT and PE, an important point especially considering the frequent though clinically silent concomitance of these two thrombotic events.     

Economic impact of an electronic alert system to prevent venous thromboembolism in hospitalised patients

Summary. Objectives: The prevention of venous thromboembolism (VTE) is a priority for improved safety in hospitalised patients. Worldwide, there is growing concern over the undersuse of appropriate thromboprophylaxis. Computerised decision support improves the implementation of thromboprophylaxis and reduces inpatient VTE. However, an economic assessment of this approach has not yet been performed. Objectives: To evaluate the economic impact of an electronic alert (e‐alert) system to prevent VTE in hospitalised patients over a 4 year period. Patients/methods: All hospitalised patients at a single institution during the first semesters of 2005–2009 (n = 32 280) were included. All cases of VTE developed during hospitalisation were followed and direct costs of diagnosis and management collected. Results: E‐alerts achieved a sustained reduction of the incidence of in‐hospital VTE, OR 0.50 (95% CI, 0.29–0.84), the impact being especially significant in medical patients, OR 0.44 (95% CI, 0.22–0.86). No increase in prophylaxis‐related bleeding was observed. In our setting, the mean direct cost (during hospitalisation and after discharge) of an in‐hospital VTE episode is €7058. Direct costs per single hospitalised patient were reduced after e‐alerts from €21.6 to €11.8, while the increased use of thromboprophylaxis and the development of e‐alerts meant €3 and €0.35 per patient, respectively. Thus, the implementation of e‐alerts led to a net cost saving of €6.5 per hospitalised patient. Should all hospitalised patients in Spain be considered, total yearly savings would approach €30 million. Conclusions: E‐alerts are useful and cost‐effective tools for thromboprophylaxis strategy in hospitalised patients. Fewer thromboembolic complications and lower costs are achieved by its implementation.     

Risk stratification for the development of venous thromboembolism in hospitalized patients with cancer

Essentials

• The Khorana score is validated for risk of venous thromboembolism (VTE) in cancer outpatients.
• We conducted a multicenter analysis of medically hospitalized cancer patients.
• Patients with a higher Khorana score on admission were more likely to develop VTE.
• The Khorana score is predictive of in‐hospital, symptomatic VTE development.

Summary

Introduction

The Khorana score is a validated risk assessment score for estimating the risk of symptomatic venous thromboembolism (VTE) in outpatients with cancer. The objective of this study was to assess the Khorana score for predicting the development of VTE in cancer patients during hospital admission.

Methods

We conducted an analysis of consecutive, adult cancer patients hospitalized for medical reasons between January and June 2010 in three academic medical centers. Information on objectively diagnosed, symptomatic VTE during hospitalization, use of anticoagulant thromboprophylaxis (TP) and Khorana score variables at the time of admission was collected.

Results

A total of 1398 patients were included. Mean age was 62 years, 51.2% were male, and mean BMI was 25.9 kg m^?2. The most frequent reasons for hospitalization were chemotherapy administration (22.3%), followed by pain control and palliation (21.4%). The overall incidence of VTE was 2.9% (95% CI, 2.0–3.8%), occurring in 5.4% (95% CI, 1.9–8.9%) of the high‐, 3.2% (95% CI, 2.0–4.4%) of the intermediate‐ and 1.4% (95% CI, 0.3–2.6%), of the low‐risk groups. High‐risk patients were more likely than low‐risk patients to have VTE (OR, 3.9; 95% CI, 1.4–11.2).

Conclusion

The Khorana score is predictive of in‐hospital, symptomatic VTE development in cancer patients who are hospitalized for medical reasons and may be a useful tool for tailoring inpatient anticoagulant thromboprophylaxis.

     

Antimicrobial prophylaxis to prevent perioperative infection in urological surgery: a multicenter study

We prospectively investigated the rates of incidence of surgical site infection (SSI), urinary tract infection (UTI), and remote infection (RI) in 4,677 patients who underwent urological surgery from January to December 2010, including 2,507 endourological cases, 1,276 clean cases, 807 clean-contaminated cases, and 87 contaminated cases involving bowel segments. A single dose of antimicrobial prophylaxis (AMP) was administered in the endourological, clean, and clean-contaminated surgery cases, except for patients who underwent transurethral resection of the prostate (TURP) or percutaneous nephrolithotripsy (PNL). AMP was administered within 72 h in TURP and PNL, and AMP was administered within 48 h in contaminated surgery cases. In cases of endourological surgery, UTI was observed in 4% and RI in 0%, and SSI, UTI, and RI were seen in 1%, 1%, and 1%, respectively, of clean surgery cases, in 3%, 3%, and 2%, respectively, of clean-contaminated surgery cases, and in 17%, 30%, and 10%, respectively, of contaminated surgery cases. In multivariate analysis of the risk factors for infection, operative time was a significant risk factor for UTI in endourological surgery, and American Society of Anesthesiologists score and operative time were significant risk factors for RI in clean surgery. No significant risk factor was found in analyses of clean-contaminated and contaminated surgery cases. A single-dose AMP regimen was shown to be effective and feasible for prevention of perioperative infection in urological surgery.     

利伐沙班和低分子量肝素钙在人工关节置换术后预防深静脉血栓形成的效果比较

目的观察利伐沙班与低分子量肝素钙预防人工关节置换术后深静脉血栓(DVT)形成的疗效。方法 2009年11月~2010年10月行膝关节置换及全髋置换的患者167例,其中全髋置换患者114例,膝关节置换患者53例。以患者住院时间顺序分为两组:利伐沙班组(n=84):术后6 h内开始使用利伐沙班10 mg/d,1次/日,口服,膝关节置换术2周,全髋置换术5周。低分子量肝素钙组(n=83):手术前2 h及手术后每天皮下注射低分子量肝素钙2500 IU,5 d。疗效评定:术前与术后行双下肢静脉超声,了解深静脉管腔大小改变、DVT发生率;凝血功能于实验开始前和治疗2 d、5 d、1周、2周、5周末各测定1次。结果①DVT发生率比较:利伐沙班组中有9例发生DVT(10.7%);低分子量肝素钙组中有15例患者发生DVT(18.1%)。②下肢静脉管腔大小前后变化比较:股浅静脉狭窄>2 mm者,利伐沙班组中有23例(27.4%),低分子量肝素钙组中有38例(45.8%);腘静脉狭窄>2 mm者,利伐沙班组中有27例(32.1%),低分子量肝素钙组中有47例(56.6%),两者比较差异有统计学意义(P<0.01)。③凝血功能检测:活化部分凝血活酶时间延长10 s以上者,利伐沙班组0例(0%),低分子量肝素钙23例(27.7%)(P<0.01)。结论利伐沙班在人工关节置换术后预防深静脉血栓形成较低分子量肝素钙效果更佳,且凝血功能几乎不受影响。     

AFFECT: a prospective,open-label,multicenter trial to evaluate the feasibility and safety of a short-term treatment with subcutaneous certoparin in patients with persistent non-valvular atrial fibrillation

BACKGROUND: Patients with persistent atrial fibrillation (AF) scheduled for electrical cardioversion need immediate anticoagulation. Unfractionated heparin (UFH) is often used for early anticoagulation in these patients before oral anticoagulation becomes effective. However, dose adjustment is required to achieve a two- to three-fold prolongation of the activated partial thromboplastin. Low molecular weight heparins, given in body weight-adjusted or independent fixed dosage, require less laboratory monitoring and are also effective within hours of first dosing. They seem to be an attractive alternative to UFH. Previous evidence has shown that these drugs are safe and effective in this indication. PATIENTS AND METHODS: In this prospective, open-label, multicenter pilot study, 203 patients were enrolled with persistent non-valvular AF scheduled for electrical cardioversion. Patients received a fixed dose of 8000 U anti-Xa certoparin twice daily starting immediately after enrolment and before cardioversion was performed. Patients with AF > 48 h underwent transoesophageal echocardiography (TEE) before cardioversion to exclude intra-atrial thrombi. After cardioversion, overlapping oral anticoagulation was started. Treatment with certoparin was stopped only after two consecutive days with INR values >2. OBJECTIVES: The objective was to document the feasibility and safety of a short-term treatment with a fixed, body weight-independent certoparin regimen (2 x 8000 U anti-Xa). RESULTS: Out of 203 patients enrolled, 200 received at least one dose of certoparin and were included in the analysis (safety population). Median treatment duration with certoparin was 7 days. Bleedings were observed in 8 patients (4.0%) and were classified as major (1.5%) or minor (2.5%). Cerebral ischemia was reported for 1 patient (0.5%). One patient showed mild thrombocytopenia (0.5%). There were no reports of venous thromboembolism or death during the treatment period. CONCLUSION: Certoparin administered at 8000 U anti-Xa twice daily independent of body weight was safe and appeared to be effective in patients with non-valvular AF undergoing electrical cardioversion. Its ease of use and the possibility of treatment on an outpatient basis make it an attractive option for early anticoagulation in AF.     

Efficacy and safety of rivaroxaban or fondaparinux thromboprophylaxis in major orthopedic surgery: findings from the ORTHO‐TEP registry

Summary. Background: Thromboprophylaxis with rivaroxaban (R) is superior to enoxaparin in patients undergoing major orthopedic surgery (MOS). However, rivaroxaban has never been directly compared with fondaparinux (F), which also shows superior efficacy over enoxaparin. The clinical impact of switching from fondaparinux to rivaroxaban thromboprophylaxis is unclear. Objectives: To evaluate the efficacy and safety of rivaroxaban or fondaparinux thromboprophylaxis in unselected patients undergoing MOS. Patients/Methods: This is a monocentric, retrospective cohort study in 5061 consecutive patients undergoing MOS at our centre, comparing rates of symptomatic VTE, bleeding and surgical complications, length of hospital stay and risk factors for VTE. Results: Rates of symptomatic VTE were 5.6% (F) and 2.1% (R; P < 0.001), with rates for distal DVT being 3.9 vs. 1.1% (P < 0.001). Rates of major VTE were numerically higher with fondaparinux (1.8 vs. 1.1%), but not statistically significant. Rates of severe bleeding (bleeding leading to surgical revision or death, occurring in a critical site, or transfusion of at least two units of packed red blood cells) were statistically lower with rivaroxaban compared with fondaparinux (2.9 vs. 4.9%; P = 0.010). The mean length of hospital stay was significantly shorter in the rivaroxaban group (8.3 days, 95% CI 8.1–8.5 vs. 9.3 days, 9.1–9.5; P < 0.001). Conclusion: Based on an indirect comparison of two consecutive cohorts, our data suggest that thromboprophylaxis with rivaroxaban is associated with less VTE and bleeding events than fondaparinux in unselected patients undergoing MOS. Prospective comparisons are warranted to confirm our findings.