Darexaban (YM150) prevents venous thromboembolism in Japanese patients undergoing major abdominal surgery: Phase III randomized, mechanical prophylaxis-controlled, open-label study

Asymptomatic Venous Thromboembolism After Hepatobiliary-Pancreatic Surgery: Early Detection Using D-dimer and Soluble Fibrin Monomer Complex Levels

AIM

The aim was to investigate the usefulness of a preemptive management strategy that includes monitoring serum D-dimer (DD) and soluble fibrin monomer complex (SFMC) levels for early detection and treatment of venous thromboembolism (VTE) after hepatobiliary-pancreatic (HBP) surgery.

METHODS

Overall, 678 patients who underwent HBP surgery between January 2010 and March 2020 were enrolled. Patients with increased postoperative serum DD or SFMC levels underwent contrast-enhanced computed tomography, and those with VTE received anticoagulant agents. The VTE risk factors were investigated using multivariable analysis. Postoperative changes in DD and SFMC levels were verified, and their ability to identify VTE was evaluated using receiver operating characteristic (ROC) analysis.

RESULTS

VTE developed in 83 patients (12.2%), and no symptomatic VTE or death due to VTE was observed. Multivariable analysis identified female sex (odds ratio [OR] 2.26; 95% confidence interval [CI] 1.41-3.60; P < .001) and surgery duration of ≥401 min (OR 2.07; 95% CI 1.27-3.35; P < .001) as independent risk factors for VTE. Maximum serum DD and SFMC levels in patients who developed VTE were significantly higher than those in patients without VTE (DD, 15.1 vs 8.9 μg/mL, P < .001; SFMC, 18.0 vs 10.2 μg/mL, P < .001, respectively). Both DD (n = 678) and the combination of DD and SFMC levels (n = 230) showed a good ability to detect VTE (area under the ROC curve, 0.804 and 0.761, respectively).

CONCLUSION

Our preemptive strategy of monitoring serum DD and SFMC levels enables early detection and treatment intervention of VTE after HBP surgery.

Prolonged thromboprophylaxis with low molecular weight heparin for abdominal or pelvic surgery

BACKGROUND

This an update of the review first published in 2009.Major abdominal and pelvic surgery carries a high risk of venous thromboembolism (VTE). The efficacy of thromboprophylaxis with low molecular weight heparin (LMWH) administered during the in-hospital period is well-documented, but the optimal duration of prophylaxis after surgery remains controversial. Some studies suggest that patients undergoing major abdominopelvic surgery benefit from prolongation of the prophylaxis up to 28 days after surgery.

OBJECTIVES

To evaluate the efficacy and safety of prolonged thromboprophylaxis with LMWH for at least 14 days after abdominal or pelvic surgery compared with thromboprophylaxis administered during the in-hospital period only in preventing late onset VTE.

SEARCH METHODS

We performed electronic searches on 28 October 2017 in the Cochrane Central Register of Controlled Trials, MEDLINE, Embase, LILACS and registered trials (Clinicaltrials.gov October 28, 2017 and World Health Organization International Clinical Trials Registry Platform (ICTRP) 28 October 2017). Abstract books from major congresses addressing thromboembolism were handsearched from 1976 to 28 October 2017, as were reference lists from relevant studies.

SELECTION CRITERIA

We assessed randomized controlled clinical trials (RCTs) comparing prolonged thromboprophylaxis (≥ fourteen days) with any LMWH agent with placebo, or other methods, or both to thromboprophylaxis during the admission period only. The population consisted of persons undergoing abdominal or pelvic surgery for both benign and malignant pathology. The outcome measures included VTE (deep venous thrombosis (DVT) or pulmonary embolism (PE)) as assessed by objective means (venography, ultrasonography, pulmonary ventilation/perfusion scintigraphy, spiral computed tomography (CT) scan or autopsy). We excluded studies exclusively reporting on clinical diagnosis of VTE without objective confirmation.

DATA COLLECTION AND ANALYSIS

Review authors identified studies and extracted data. Outcomes were VTE (DVT or PE) assessed by objective means. Safety outcomes were defined as bleeding complications and mortality within three months after surgery. Sensitivity analyses were also performed with unpublished studies excluded, and with study participants limited to those undergoing solely open and not laparoscopic surgery. We used a fixed-effect model for analysis.

MAIN RESULTS

We identified seven RCTs (1728 participants) evaluating prolonged thromboprophylaxis with LMWH compared with control or placebo. The searches resulted in 1632 studies, of which we excluded 1528. One hundred and four abstracts, eligible for inclusion, were assessed of which seven studies met the inclusion criteria.For the primary outcome, the incidence of overall VTE after major abdominal or pelvic surgery was 13.2% in the control group compared to 5.3% in the patients receiving out-of-hospital LMWH (Mantel Haentzel (M-H) odds ratio (OR) 0.38, 95% confidence interval (CI) 0.26 to 0.54; I2 = 28%; moderate-quality evidence).For the secondary outcome of all DVT, seven studies, n = 1728, showed prolonged thromboprophylaxis with LMWH to be associated with a statistically significant reduction in the incidence of all DVT (M-H OR 0.39, 95% CI 0.27 to 0.55; I2 = 28%; moderate-quality evidence).We found a similar reduction when analysis was limited to incidence in proximal DVT (M-H OR 0.22, 95% CI 0.10 to 0.47; I2 = 0%; moderate-quality evidence).The incidence of symptomatic VTE was also reduced from 1.0% in the control group to 0.1% in patients receiving prolonged thromboprophylaxis, which approached significance (M-H OR 0.30, 95% CI 0.08 to 1.11; I2 = 0%; moderate-quality evidence).No difference in the incidence of bleeding between the control and LMWH group was found, 2.8% and 3.4%, respectively (M-H OR 1.10, 95% CI 0.67 to 1.81; I2 = 0%; moderate-quality evidence).No difference in mortality between the control and LMWH group was found, 3.8% and 3.9%, respectively (M-H OR 1.15, 95% CI 0.72 to 1.84; moderate-quality evidence).Estimates of heterogeneity ranged between 0% and 28% depending on the analysis, suggesting low or unimportant heterogeneity.

AUTHORS' CONCLUSIONS

Prolonged thromboprophylaxis with LMWH significantly reduces the risk of VTE compared to thromboprophylaxis during hospital admittance only, without increasing bleeding complications or mortality after major abdominal or pelvic surgery. This finding also holds true for DVT alone, and for both proximal and symptomatic DVT. The quality of the evidence is moderate and provides moderate support for routine use of prolonged thromboprophylaxis. Given the low heterogeneity between studies and the consistent and moderate evidence of a decrease in risk for VTE, our findings suggest that additional studies may help refine the degree of risk reduction but would be unlikely to significantly influence these findings. This updated review provides additional evidence and supports the previous results reported in the 2009 review.

Prolonged thromboprophylaxis with low molecular weight heparin for abdominal or pelvic surgery

BACKGROUND

This an update of the review first published in 2009.Major abdominal and pelvic surgery carries a high risk of venous thromboembolism (VTE). The efficacy of thromboprophylaxis with low molecular weight heparin (LMWH) administered during the in-hospital period is well-documented, but the optimal duration of prophylaxis after surgery remains controversial. Some studies suggest that patients undergoing major abdominopelvic surgery benefit from prolongation of the prophylaxis up to 28 days after surgery.

OBJECTIVES

To evaluate the efficacy and safety of prolonged thromboprophylaxis with LMWH for at least 14 days after abdominal or pelvic surgery compared with thromboprophylaxis administered during the in-hospital period only in preventing late onset VTE.

SEARCH METHODS

We performed electronic searches on 28 October 2017 in the Cochrane Central Register of Controlled Trials, MEDLINE, Embase, LILACS and registered trials (Clinicaltrials.gov October 28, 2017 and World Health Organization International Clinical Trials Registry Platform (ICTRP) 28 October 2017). Abstract books from major congresses addressing thromboembolism were handsearched from 1976 to 28 October 2017, as were reference lists from relevant studies.

SELECTION CRITERIA

We assessed randomized controlled clinical trials (RCTs) comparing prolonged thromboprophylaxis (≥ fourteen days) with any LMWH agent with placebo, or other methods, or both to thromboprophylaxis during the admission period only. The population consisted of persons undergoing abdominal or pelvic surgery for both benign and malignant pathology. The outcome measures included VTE (deep venous thrombosis (DVT) or pulmonary embolism (PE)) as assessed by objective means (venography, ultrasonography, pulmonary ventilation/perfusion scintigraphy, spiral computed tomography (CT) scan or autopsy). We excluded studies exclusively reporting on clinical diagnosis of VTE without objective confirmation.

DATA COLLECTION AND ANALYSIS

Review authors identified studies and extracted data. Outcomes were VTE (DVT or PE) assessed by objective means. Safety outcomes were defined as bleeding complications and mortality within three months after surgery. Sensitivity analyses were also performed with unpublished studies excluded, and with study participants limited to those undergoing solely open and not laparoscopic surgery. We used a fixed-effect model for analysis.

MAIN RESULTS

We identified seven RCTs (1728 participants) evaluating prolonged thromboprophylaxis with LMWH compared with control or placebo. The searches resulted in 1632 studies, of which we excluded 1528. One hundred and four abstracts, eligible for inclusion, were assessed of which seven studies met the inclusion criteria.For the primary outcome, the incidence of overall VTE after major abdominal or pelvic surgery was 13.2% in the control group compared to 5.3% in the patients receiving out-of-hospital LMWH (Mantel Haentzel (M-H) odds ratio (OR) 0.38, 95% confidence interval (CI) 0.26 to 0.54; I2 = 28%; moderate-quality evidence).For the secondary outcome of all DVT, seven studies, n = 1728, showed prolonged thromboprophylaxis with LMWH to be associated with a statistically significant reduction in the incidence of all DVT (M-H OR 0.39, 95% CI 0.27 to 0.55; I2 = 28%; moderate-quality evidence).We found a similar reduction when analysis was limited to incidence in proximal DVT (M-H OR 0.22, 95% CI 0.10 to 0.47; I2 = 0%; moderate-quality evidence).The incidence of symptomatic VTE was also reduced from 1.0% in the control group to 0.1% in patients receiving prolonged thromboprophylaxis (M-H OR 0.30, 95% CI 0.08 to 1.11; I2 = 0%; moderate-quality evidence).No difference in the incidence of bleeding between the control and LMWH group was found, 2.8% and 3.4%, respectively (M-H OR 1.10, 95% CI 0.67 to 1.81; I2 = 0%; moderate-quality evidence).No difference in mortality between the control and LMWH group was found, 3.8% and 3.9%, respectively (M-H OR 1.15, 95% CI 0.72 to 1.84; moderate-quality evidence).Estimates of heterogeneity ranged between 0% and 28% depending on the analysis, suggesting low or unimportant heterogeneity.

AUTHORS' CONCLUSIONS

Prolonged thromboprophylaxis with LMWH significantly reduces the risk of VTE compared to thromboprophylaxis during hospital admittance only, without increasing bleeding complications or mortality after major abdominal or pelvic surgery. This finding also holds true for DVT alone, and for both proximal and symptomatic DVT. The quality of the evidence is moderate and provides moderate support for routine use of prolonged thromboprophylaxis. Given the low heterogeneity between studies and the consistent and moderate evidence of a decrease in risk for VTE, our findings suggest that additional studies may help refine the degree of risk reduction but would be unlikely to significantly influence these findings. This updated review provides additional evidence and supports the previous results reported in the 2009 review.

Prolonged thromboprophylaxis with low molecular weight heparin for abdominal or pelvic surgery

BACKGROUND

This an update of the review first published in 2009.Major abdominal and pelvic surgery carries a high risk of venous thromboembolism (VTE). The efficacy of thromboprophylaxis with low molecular weight heparin (LMWH) administered during the in-hospital period is well-documented, but the optimal duration of prophylaxis after surgery remains controversial. Some studies suggest that patients undergoing major abdominopelvic surgery benefit from prolongation of the prophylaxis up to 28 days after surgery.

OBJECTIVES

To evaluate the efficacy and safety of prolonged thromboprophylaxis with LMWH for at least 14 days after abdominal or pelvic surgery compared with thromboprophylaxis administered during the in-hospital period only in preventing late onset VTE.

SEARCH METHODS

We performed electronic searches on 28 October 2017 in the Cochrane Central Register of Controlled Trials, MEDLINE, Embase, LILACS and registered trials (Clinicaltrials.gov October 28, 2017 and World Health Organization International Clinical Trials Registry Platform (ICTRP) 28 October 2017). Abstract books from major congresses addressing thromboembolism were handsearched from 1976 to 28 October 2017, as were reference lists from relevant studies.

SELECTION CRITERIA

We assessed randomized controlled clinical trials (RCTs) comparing prolonged thromboprophylaxis (≥ fourteen days) with any LMWH agent with placebo, or other methods, or both to thromboprophylaxis during the admission period only. The population consisted of persons undergoing abdominal or pelvic surgery for both benign and malignant pathology. The outcome measures included VTE (deep venous thrombosis (DVT) or pulmonary embolism (PE)) as assessed by objective means (venography, ultrasonography, pulmonary ventilation/perfusion scintigraphy, spiral computed tomography (CT) scan or autopsy). We excluded studies exclusively reporting on clinical diagnosis of VTE without objective confirmation.

DATA COLLECTION AND ANALYSIS

Review authors identified studies and extracted data. Outcomes were VTE (DVT or PE) assessed by objective means. Safety outcomes were defined as bleeding complications within three months after surgery. Sensitivity analyses were also performed with unpublished studies excluded, and with study participants limited to those undergoing solely open and not laparoscopic surgery. We used a fixed-effect model for analysis.

MAIN RESULTS

We identified seven RCTs (1728 participants) evaluating prolonged thromboprophylaxis with LMWH compared with control or placebo. The searches resulted in 1632 studies, of which we excluded 1528. One hundred and four abstracts, eligible for inclusion, were assessed of which seven studies met the inclusion criteria.For the primary outcome, the incidence of overall VTE after major abdominal or pelvic surgery was 13.2% in the control group compared to 5.3% in the patients receiving out-of-hospital LMWH (Mantel Haentzel (M-H) odds ratio (OR) 0.38, 95% confidence interval (CI) 0.26 to 0.54; I2 = 28%; seven studies, n = 1728; moderate-quality evidence).For the secondary outcome of all DVT, seven studies, n = 1728, showed prolonged thromboprophylaxis with LMWH to be associated with a statistically significant reduction in the incidence of all DVT (M-H OR 0.39, 95% CI 0.27 to 0.55; I2 = 28%; moderate-quality evidence).We found a similar reduction when analysis was limited to incidence in proximal DVT (M-H OR 0.22, 95% CI 0.10 to 0.47; I2 = 0%; moderate-quality evidence).The incidence of symptomatic VTE was also reduced from 1.0% in the control group to 0.1% in patients receiving prolonged thromboprophylaxis (M-H OR 0.30, 95% CI 0.08 to 1.11; I2 = 0%; moderate-quality evidence).No difference in the incidence of bleeding between the control and LMWH group was found, 2.8% and 3.4%, respectively (HM-H OR 1.10, 95% CI 0.67 to 1.81; I2 = 0%; seven studies, n = 2239; moderate-quality evidence).Estimates of heterogeneity ranged between 0% and 28% depending on the analysis, suggesting low or unimportant heterogeneity.

AUTHORS' CONCLUSIONS

Prolonged thromboprophylaxis with LMWH significantly reduces the risk of VTE compared to thromboprophylaxis during hospital admittance only, without increasing bleeding complications after major abdominal or pelvic surgery. This finding also holds true for DVT alone, and for both proximal and symptomatic DVT. The quality of the evidence is moderate and provides moderate support for routine use of prolonged thromboprophylaxis. Given the low heterogeneity between studies and the consistent and moderate evidence of a decrease in risk for VTE, our findings suggest that additional studies may help refine the degree of risk reduction but would be unlikely to significantly influence these findings. This updated review provides additional evidence and supports the previous results reported in the 2009 review.

Graduated compression stockings for prevention of deep vein thrombosis

BACKGROUND

Hospitalised patients are at increased risk of developing deep vein thrombosis (DVT) in the lower limb and pelvic veins, on a background of prolonged immobilisation associated with their medical or surgical illness. Patients with DVT are at increased risk of developing a pulmonary embolism (PE). The use of graduated compression stockings (GCS) in hospitalised patients has been proposed to decrease the risk of DVT. This is an update of a Cochrane Review first published in 2000, and last updated in 2014.

OBJECTIVES

To evaluate the effectiveness and safety of graduated compression stockings in preventing deep vein thrombosis in various groups of hospitalised patients.

SEARCH METHODS

For this review the Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), and trials registries on 21 March 2017; and the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE Ovid, Embase Ovid, CINAHL Ebsco, AMED Ovid , and trials registries on 12 June 2018.

SELECTION CRITERIA

Randomised controlled trials (RCTs) involving GCS alone, or GCS used on a background of any other DVT prophylactic method. We combined results from both of these groups of trials.

DATA COLLECTION AND ANALYSIS

Two review authors (AS, MD) assessed potentially eligible trials for inclusion. One review author (AS) extracted the data, which a second review author (MD) cross-checked and authenticated. Two review authors (AS, MD) assessed the methodological quality of trials with the Cochrane 'Risk of bias' tool. Any disagreements were resolved by discussion with the senior review author (TL). For dichotomous outcomes, we calculated the Peto odds ratio and corresponding 95% confidence interval. We pooled data using a fixed-effect model. We used the GRADE system to evaluate the overall quality of the evidence supporting the outcomes assessed in this review.

MAIN RESULTS

We included 20 RCTs involving a total of 1681 individual participants and 1172 individual legs (2853 analytic units). Of these 20 trials, 10 included patients undergoing general surgery; six included patients undergoing orthopaedic surgery; three individual trials included patients undergoing neurosurgery, cardiac surgery, and gynaecological surgery, respectively; and only one trial included medical patients. Graduated compression stockings were applied on the day before surgery or on the day of surgery and were worn up until discharge or until the participants were fully mobile. In the majority of the included studies DVT was identified by the radioactive I¹²⁵ uptake test. Duration of follow-up ranged from seven to 14 days. The included studies were at an overall low risk of bias.We were able to pool the data from 20 studies reporting the incidence of DVT. In the GCS group, 134 of 1445 units developed DVT (9%) in comparison to the control group (without GCS), in which 290 of 1408 units developed DVT (21%). The Peto odds ratio (OR) was 0.35 (95% confidence interval (CI) 0.28 to 0.43; 20 studies; 2853 units; high-quality evidence), showing an overall effect favouring treatment with GCS (P < 0.001).Based on results from eight included studies, the incidence of proximal DVT was 7 of 517 (1%) units in the GCS group and 28 of 518 (5%) units in the control group. The Peto OR was 0.26 (95% CI 0.13 to 0.53; 8 studies; 1035 units; moderate-quality evidence) with an overall effect favouring treatment with GCS (P < 0.001). Combining results from five studies, all based on surgical patients, the incidence of PE was 5 of 283 (2%) participants in the GCS group and 14 of 286 (5%) in the control group. The Peto OR was 0.38 (95% CI 0.15 to 0.96; 5 studies; 569 participants; low-quality evidence) with an overall effect favouring treatment with GCS (P = 0.04). We downgraded the quality of the evidence for proximal DVT and PE due to low event rate (imprecision) and lack of routine screening for PE (inconsistency).We carried out subgroup analysis by speciality (surgical or medical patients). Combining results from 19 trials focusing on surgical patients, 134 of 1365 (9.8%) units developed DVT in the GCS group compared to 282 of 1328 (21.2%) units in the control group. The Peto OR was 0.35 (95% CI 0.28 to 0.44; high-quality evidence), with an overall effect favouring treatment with GCS (P < 0.001). Based on results from seven included studies, the incidence of proximal DVT was 7 of 437 units (1.6%) in the GCS group and 28 of 438 (6.4%) in the control group. The Peto OR was 0.26 (95% CI 0.13 to 0.53; 875 units; moderate-quality evidence) with an overall effect favouring treatment with GCS (P < 0.001). We downgraded the evidence for proximal DVT due to low event rate (imprecision).Based on the results from one trial focusing on medical patients admitted following acute myocardial infarction, 0 of 80 (0%) legs developed DVT in the GCS group and 8 of 80 (10%) legs developed DVT in the control group. The Peto OR was 0.12 (95% CI 0.03 to 0.51; low-quality evidence) with an overall effect favouring treatment with GCS (P = 0.004). None of the medical patients in either group developed a proximal DVT, and the incidence of PE was not reported.Limited data were available to accurately assess the incidence of adverse effects and complications with the use of GCS as these were not routinely quantitatively reported in the included studies.

AUTHORS' CONCLUSIONS

There is high-quality evidence that GCS are effective in reducing the risk of DVT in hospitalised patients who have undergone general and orthopaedic surgery, with or without other methods of background thromboprophylaxis, where clinically appropriate. There is moderate-quality evidence that GCS probably reduce the risk of proximal DVT, and low-quality evidence that GCS may reduce the risk of PE. However, there remains a paucity of evidence to assess the effectiveness of GCS in diminishing the risk of DVT in medical patients.

Darexaban (YM150) versus enoxaparin for the prevention of venous thromboembolism after total hip arthroplasty: a randomised phase IIb dose confirmation study (ONYX-3)

This double-blind, double-dummy, randomised, phase IIb study (NCT00902928) evaluated different dosing regimens of darexaban compared with enoxaparin (randomised 1:1:1:1:1 to 15 mg twice daily [bid], 30 mg once daily [qd], 30 mg bid or 60 mg qd or enoxaparin 40 mg qd) in patients undergoing elective total hip arthroplasty. Patients, investigators, pharmacists and sponsor were all blinded to treatment allocation. Darexaban administration started 6-10 hours (h) post-surgery. Enoxaparin 40 mg qd administration started 12 ± 2 h before surgery. Treatment continued for 35 days. Bilateral venography was performed on Day 10 ± 2. The primary efficacy outcome was total VTEs (composite of proximal/distal deep-vein thrombosis, pulmonary embolism) or death, at Day 12. Total VTE rates were similar across all groups. There was no apparent difference in efficacy between onceand twice-daily darexaban (odds ratio [OR] 1.00; 95% confidence interval [CI] 0.71–1.42; p=0.988), or total daily dose (30 mg/day vs 60 mg/day; OR 0.81; 95% CI 0.57–1.15; p=0.244). There was no significant difference in major and/or clinically relevant non-major bleeding between darexaban qd or bid, or between total daily doses of 30 mg or 60 mg, and also for any dosing regimen of darexaban vs enoxaparin. Darexaban was well tolerated, without signs of liver toxicity. In conclusion, darexaban, administered qd or bid, and at total daily doses of 30 mg or 60 mg, appears to be effective for VTE prevention and was well tolerated. Data suggest no significant differences between a once- or twice-daily dosing regimen.

A Phase II, double-blind, randomized, parallel group, dose-finding study of the safety and tolerability of darexaban compared with warfarin in patients with non-valvular atrial fibrillation: the oral factor Xa inhibitor for prophylaxis of stroke in atrial fibrillation study 2 (OPAL-2)

BACKGROUND

Darexaban (YM150) is a novel oral anticoagulant that directly inhibits factor Xa.

OBJECTIVES

To investigate the optimal daily dose regimen of YM150 in subjects with non-valvular atrial fibrillation (NVAF).

METHODS

In this multicenter, double-blind, double-dummy, randomized, parallel-group, dose-confirmation study (NCT00938730), patients with NVAF were randomized to darexaban 15 mg bid, 30 mg qd, 30 mg bid, 60 mg qd, 60 mg bid or 120 mg qd, or warfarin qd. The primary endpoint was the incidence of adjudicated major and/or clinically relevant non-major bleeding events. Secondary endpoints included efficacy, pharmacodynamics, safety and tolerability.

RESULTS

A total of 1297 patients were randomized and finally included in the trial (median age, 66 [range 30-89] years; 68.8% male): 981 completed treatment for a median of 28 weeks (interquartile range, 24-36). At daily doses of 30-60 mg, darexaban bid resulted in fewer bleeding events than darexaban qd. For darexaban 120 mg, the bid regimen produced more bleeding events than the qd regimen. Although few efficacy endpoints occurred, these decreased with increasing daily darexaban dose. Darexaban decreased plasma D-dimer levels (index of thrombogenesis) after 4 weeks of treatment by 21.5-33.8% compared with baseline, which was comparable with warfarin at the higher darexaban doses. Darexaban was well tolerated with no liver toxicity.

CONCLUSIONS

In this Phase II study in patients with NVAF, a lower bleeding rate was observed in the 120 mg daily darexaban group compared with warfarin with a reduction in plasma D-dimer as marker for hemostasis. Further investigation of the optimal dose of darexaban for the prevention of stroke in patients with NVAF would need to be considered.

Risk of insomnia with non-vitamin K oral anticoagulants: systematic review and meta-analysis

PURPOSE

Insomnia is an important adverse event of mechanical thromboprophylaxis. This sleep disorder has been reported as one of the commonest adverse events of the new oral anti-Xa anticoagulant darexaban, with similar rates to mechanical thromboprophylaxis in a randomized controlled trial (RCT). However, the perceived effect could have been biased because it was an open-label RCT. Therefore, we aimed to review the incidence of insomnia with non-vitamin K antagonist oral anticoagulants (NOACs).

METHODS

We performed a systematic review and meta-analysis of Phase III RCTs. Electronic databases MEDLINE and CENTRAL (inception to September 2013) were searched as well as review articles and references of included studies. We included phase III RCTs which compared NOACs with any other control group. Data were analyzed and pooled to estimate risk ratio (RR) with 95% confidence intervals (95%CI) for insomnia using inverse variance method. Statistical heterogeneity was evaluated with I(2) test.

RESULTS

We included seven studies (two apixaban RCTs, two dabigatran RCTs, one darexaban RCTs, and two rivaroxaban RCTs), enrolling a total of 23,023 patients. Overall, NOACs were not associated to an increased risk of insomnia: RR 0.94 (95%CI 0.83-1.08; I(2) = 0%). In blinded studies (six studies), NOACs also did not show increased risk of insomnia (RR 0.94, 95%CI 0.83-1.08; I(2) = 0%). Results were similar irrespective of the comparators.

CONCLUSIONS

NOACs (apixaban, dabigatran, darexaban, rivaroxaban) did not show increased risk of insomnia. Results according to study design (blinded vs. open-label trials) overlap the main analysis.

Graduated compression stockings for prevention of deep vein thrombosis

BACKGROUND

One of the settings where deep vein thrombosis (DVT) in the lower limb and pelvic veins occurs is in hospital with prolonged immobilisation of patients for various surgical and medical illnesses. Using graduated compression stockings (GCS) in these patients has been proposed to decrease the risk of DVT. This is an update of a Cochrane review first published in 2000 and updated in 2010.

OBJECTIVES

To evaluate the effectiveness and safety of graduated compression stockings in preventing DVT in various groups of hospitalised patients.

SEARCH METHODS

For this update the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched March 2014) and CENTRAL (2014, Issue 2).

SELECTION CRITERIA

Randomised controlled trials (RCTs) involving GCS alone; or GCS used on a background of any other DVT prophylactic method. Results from both these groups of trials were combined in this update.

DATA COLLECTION AND ANALYSIS

For this update one review author (AS) extracted the data. These were cross-checked and authenticated by a second author (MJD). Two review authors (AS and MJD) assessed the quality of trials. Disagreements were resolved by discussion.

MAIN RESULTS

Nineteen RCTs were identified involving 1681 individual patients and 1064 individual legs (2745 analytic units). Of these 19 trials, nine included patients undergoing general surgery, six included patients undergoing orthopaedic surgery, and only one trial included medical patients. Graduated compression stockings were applied on the day before surgery or on the day of surgery and were worn up until discharge or until the patients were fully mobile. In the majority of the included studies DVT was identified by the radioactive I(125) uptake test. Overall, included studies were of good quality.In the treatment group (GCS) of 1391 units 126 developed DVT (9%) in comparison to the control group (without GCS) of 1354 units where 282 (21%) developed DVT. The Peto odds ratio (OR) was 0.33 (95% confidence interval (CI) 0.26 to 0.41) with an overall effect favouring treatment with GCS (P < 0.00001).Based on results from eight included studies, the incidence of proximal DVT was 7 of 517 (1%) units in the treatment group and 28 of 518 (5%) units in the control group. The Peto OR was 0.26 (95% CI 0.13 to 0.53) with an overall effect favouring treatment with GCS (P = 0.0002). Based on results from five included studies, the incidence of PE was 5 of 283 (2%) participants in the treatment group and 14 of 286 (5%) in the control group. The Peto OR was 0.38 (95% CI 0.15 to 0.96) with an overall effect favouring treatment with GCS (P = 0.04). Limited data were available to accurately assess the incidence of adverse effects and complications with the use of GCS.

AUTHORS' CONCLUSIONS

GCS are effective in diminishing the risk of DVT in hospitalised patients, with strong evidence favouring their use in general and orthopaedic surgery. However, evidence for their effectiveness in medical patients is limited to one trial.

Use of novel oral anticoagulants for the treatment of venous thromboembolism and its considerations in Asian patients

Parenteral anticoagulation followed by warfarin has been conventionally used for the treatment of venous thromboembolism (VTE). However, there are numerous troublesome characteristics of warfarin that prompted the development of novel oral anticoagulants (NOACs) for the treatment of VTE. Asians are reported to be at an increased risk of bleeding with warfarin, and while the reported incidence of VTE in Asians is lower than in Caucasians, the annual rate of VTE in Asia is rising along with the need for better oral anticoagulant options. Recently, several Phase III clinical trials with NOACs for the treatment and prevention of VTE recurrence have been published. For the treatment of VTE, the four NOACs - dabigatran, rivaroxaban, apixaban, and edoxaban - each showed comparable efficacy outcomes while resulting in better safety outcomes when compared with conventional treatment. In these trials, Asian patients had comparable efficacy and safety outcomes as other races, except in the edoxaban trial, in which the Asian subgroup had better safety profiles than other races, although further confirmation is necessary. For secondary prevention, dabigatran was compared with conventional treatment and showed similar efficacy and safety outcomes. When NOACs were compared with placebo for secondary prevention of VTE, they showed superior efficacy and increased bleeding except for apixaban, which showed comparable major bleeding and composite of major and clinically relevant nonmajor bleeding rates as placebo. No significant differences in the outcomes based on race were observed in the Asian subgroups for secondary prevention. Therefore, NOACs can be used with similar efficacy and at least similar or superior safety compared with conventional treatment in the treatment of VTE, and at no increased risk in Asian patients.

Safety of postoperative thromboprophylaxis after major hepatobiliary-pancreatic surgery in Japanese patients

BACKGROUND AND PURPOSE

Thromboprophylaxis is recommended for preventing postoperative venous thromboembolism (VTE) after abdominal surgery; however, its use after major hepatobiliary-pancreatic surgery is typically avoided as it increases the risk of bleeding. We conducted this study to evaluate the safety of thromboprophylaxis after major hepatobiliary-pancreatic surgery.

METHODS

We analyzed the rates of postoperative bleeding, VTE, morbidity, and prolonged hospital stay in 349 patients who underwent major hepatobiliary-pancreatic surgery, such as pancreaticoduodenectomy, hemihepatectomy or greater, and hepatopancreaticoduodenectomy.

RESULTS

Chemical thromboprophylaxis was associated with significantly increased rates and risks of overall bleeding events vs. no chemical thromboprophylaxis (26.6 vs. 8.5%, respectively). The rate of minor hemorrhage was significantly higher in patients who received chemical thromboprophylaxis (21.7 vs. 3.5%); however, there were no differences in the rate of major hemorrhage requiring blood transfusion or hemostatic intervention between the groups (4.8 vs. 4.9%). The postoperative VTE rate was also significantly decreased by chemical thromboprophylaxis (2.9 vs. 7.7%). However, chemical thromboprophylaxis did not affect the rate of SSI, severe morbidity, or duration of the postoperative hospital stay.

CONCLUSION

We consider that chemical thromboprophylaxis is beneficial and can be safely used even after major hepatobiliary-pancreatic surgery.

Risk of drug-induced liver injury with the new oral anticoagulants: systematic review and meta-analysis

OBJECTIVE

In recent years, safety alerts have been made warning of the risk of serious drug-induced liver injury (DILI) caused by cardiovascular drugs. The new oral anticoagulants (NOACs) have now reached the market. However, safety concerns have been raised about their hepatic safety. Therefore we aimed to evaluate NOAC liver-related safety.

METHODS

Systematic review and meta-analysis of phase III randomised controlled trials (RCTs). Medline and CENTRAL were searched to September 2013. Reviews and reference lists were also searched. Two reviewers independently searched for studies and retrieved data estimates. Primary outcome was DILI (transaminases elevations >3× upper limit of normal (ULN) with total bilirubin >2× ULN). NOACs were compared against any control group. Random-effects meta-analysis was performed, and pooled estimates were expressed as relative risk (RR) and 95% CI heterogeneity was evaluated with I(2) test.

RESULTS

Twenty-nine RCTs evaluating 152 116 patients (mean follow-up of 16 months) were included. All RCTs were rated as having low risk of bias. NOAC were not associated with an increased risk of DILI (RR 0.90, 95% CI 0.72 to 1.13, I(2)=0%). Similar results were obtained for individual NOAC (rivaroxaban, apixaban, dabigatran, darexaban, edoxaban) and considering the different control groups (vitamin K antagonists, low molecular weight heparin (LMWH) and placebo). The risk of transaminases elevations (>3×ULN) was lower among NOAC-treated patients, in particular in comparison with LMWH-treated patients (RR 0.71, 95% CI 0.59 to 0.85; I(2)=27%)

CONCLUSIONS

NOACs are not associated with an increased risk of DILI. The unexpected 'protective' effect of NOAC is probably due to LMWH-associated hepatotoxicity.

Novel oral anticoagulants for the prevention of venous thromboembolism in surgical patients

Pharmacologic prophylaxis with low-dose unfractionated heparin, low molecular weight heparin or fondaparinux has clearly demonstrated to reduce the rate of thromboembolic events in surgical patients. In the last decade, several novel oral anticoagulants have been tested in surgical patients, but only in the setting of major orthopedic surgery. Based on the results of the studies, dabigatran, rivaroxaban and apixaban have been approved by the European Medicines Agency for the prevention of venous thromboembolism after elective hip or knee replacement surgery. The novel anticoagulants represent an appealing alternative to current prophylaxis strategies that are mostly based on subcutaneous injection of low molecular weight heparin and have also been recommended by recently updated guidelines. Their role in other settings, such as hip fracture surgery, or in non-orthopedic surgery, may deserve future evaluation.

Darexaban: anticoagulant effects in mice and human plasma in vitro, antithrombotic effects in thrombosis and bleeding models in mice and effects of anti-inhibitor coagulant complex and recombinant factor VIIa

Here, we investigated the anticoagulant effects of darexaban in mice and human plasma in vitro, effects of darexaban in thrombosis and bleeding models in mice, and reversal effects of anti-inhibitor coagulant complex (ACC) and recombinant factor VIIa (rFVIIa) on anticoagulant effects of darexaban. In mice, darexaban inhibited FXa activity in plasma with an ED50 value of 24.8 mg/kg. Both darexaban and warfarin prolonged prothrombin time (PT) at 3 mg/kg and 0.3 mg/kg/day, respectively. PT and activated partial thromboplastin time (aPTT) prolonged by darexaban were dose-dependently reversed by intravenously-administered rFVIIa, significantly so at 1 mg/kg. In a pulmonary thromboembolism (PE) mouse model, both darexaban and warfarin dose-dependently reduced the mortality rate, significantly so at 10 mg/kg and 3 mg/kg/day, respectively. In a FeCl3-induced venous thrombosis (VT) mouse model, darexaban (0.3-10 mg/kg) dose-dependently decreased the thrombus protein content, significantly so at doses of 3 mg/kg or higher. In a tail-transection mouse model, darexaban had no significant effect on the amount of blood loss at doses up to 10 mg/kg, while warfarin showed a dose-dependent increase in blood loss, significantly so from 1 mg/kg/day. Darexaban and its metabolite darexaban glucuronide significantly prolonged PT and aPTT in human plasma in vitro, and while rFVIIa concentration-dependently reversed the prolonged PT in this plasma, ACC dose-dependently reversed both PT and aPTT changes prolonged by darexaban. Taken together, these results suggest that darexaban has a potential to be an oral anticoagulant with a better safety profile than warfarin, and that rFVIIa and ACC may be useful as antidotes to darexaban in cases of overdose.