A critical appraisal of bleeding events reported in venous thromboembolism prevention trials of patients undergoing hip and knee arthroplasty

Total Hip Arthroplasty in Patients Who Have Factor V Leiden: Elevated Risks Isolated to Venous Thromboembolism Events

BACKGROUND

Total hip arthroplasty (THA) is a common procedure that requires consideration of pre-existing comorbidities. Factor V Leiden (FVL), an inherited thrombophilia, is one such condition that predisposes patients to venous thromboembolism (VTE, deep vein thrombosis [DVT], and pulmonary embolism [PE]). The present study aimed to characterize the risks associated with FVL patients undergoing THA and evaluate the effect of VTE chemoprophylactic agents on these risks.

METHODS

A total of 544,022 adult patients who underwent primary THA for osteoarthritis indications between 2010 and October 2021 were identified in an administrative claims database. Of these, FVL was identified in 1,138 (0.21%). Patients who had and did not have FVL were matched at a 1:4 ratio (1,131 with FVL and 4,519 without FVL) based on age, sex, and Elixhauser Comorbidity Index. Univariable and multivariable analyses were assessed for 90-day complications. Implant survival at five years was assessed and compared with log-rank tests. The relative use of different chemoprophylactic agents, including aspirin, warfarin, heparin, or direct oral anticoagulant (DOAC), was assessed. Bleeding-events and VTE were compared for those prescribed either aspirin or warfarin, heparin, or DOAC. A Bonferroni correction was applied.

RESULTS

On multivariable analysis, FVL patients were found to have increased odds of 90-day DVT (odds ratio (OR) = 9.20), PE (OR = 6.89), and aggregated serious and all adverse events (OR = 4.74 and 1.98, respectively), but not elevated risk of other perioperative adverse events or five-year reoperations. More potent chemoprophylactic agents (warfarin, heparin, DOAC) reduced, but did not completely eliminate, the increased VTE risks (without increasing bleeding events).

CONCLUSION

This study quantified the significantly elevated VTE risk associated with FVL patients undergoing THA. The lack of difference in other specific adverse events and five-year reoperations is reassuring. Clearly, chemoprophylactic agents are important in this population and may need further attention.

The effects of three different low-molecular-weight heparins on blood loss after intramedullary nailing of trochanteric fractures

PURPOSE

The purpose of this study was to compare the effects of reviparin, dalteparin and enoxaparin on intraoperative blood loss in patients with trochanteric fracture treated with intramedullary nailing.

MATERIALS AND METHODS

This retrospective multicenter study included 100 patients with trochanteric fracture who were divided into three groups according to the low-molecular-weight heparin administered. In all cases, a short third generation Gamma nail was used for osteosynthesis. Complete blood count and number of red blood cell transfusions (RBC) were evaluated.

RESULTS

The mean value of postoperative haemoglobin level was lower in the enoxaparin group compared to the reviparin group, with significant difference (p = 0.001; 95% CI 4.1-18.87). Patients in the dalteparin group received more RBC transfusions compared to the reviparin and enoxaparin group (p = 0.048).

CONCLUSION

The use of enoxaparin and dalteparin in hip fracture patients can result in lower postoperative haemoglobin levels and more RBC transfusions compared to reviparin.

The Effects of Three Different Low-molecular-weight Heparins on Blood Loss After Intramedullary Nailing of Trochanteric Fractures

Background

The three most commonly used low-molecular-weight heparins (LMWH) in Bosnia and Herzegovina for thromboprophylaxis in patients with hip fracture are reviparin, dalteparin and enoxaparin.

Objective

The purpose of this study was to compare the effects of reviparin, dalteparin and enoxaparin on intraoperative blood loss in patients with trochanteric fracture treated with intramedullary nailing.

Methods

This retrospective multicenter study included 100 patients with trochanteric fracture who were divided into three groups according to the low-molecular-weight heparin administered. In all cases, a short third generation Gamma-nail was used for osteosynthesis. Complete blood count and number of red blood cell transfusions (RBC) were evaluated. Results: The mean value of postoperative hemoglobin level was lower in the enoxaparin group compared to the reviparin group, with significant difference (p=0.001; 95% CI: 4.1-18.87). Patients in the dalteparin group received more RBC transfusions compared to the reviparin and enoxaparin group (p=0.048).

Conclusion

The use of enoxaparin and dalteparin in hip fracture patients can result in lower postoperative haemoglobin levels and more RBC transfusions compared to reviparin.

Risk factors for venous thromboembolism following fractures isolated to the foot and ankle fracture

OBJECTIVE

Venous thromboembolism (VTE) is an uncommon, but potentially morbid, complication following foot and ankle fractures. Current standard is to not administer thromboprophylaxis to patients with such injuries. Nonetheless, patient and fracture factors might affect this risk/benefit consideration. The goal of this study was to determine what patients are most at risk.

METHODS

The M53Ortho Pearldiver database was used to identify patients with fractures isolated to the foot and ankle that were treated non-operatively or operatively. Patients with pilon, other appendicular fractures remote from the foot and ankle, and other traumatic injuries were excluded. The 90-day occurrence of VTE was identified based on codes for deep vein thrombosis or pulmonary embolism. Characteristics of those patients who did and did not have VTEs were compared using chi-square analyses. Multivariate logistical regression was then performed to determined factors independently associated with VTE. Finally, timing of VTE relative to fracture was analyzed.

RESULTS

A total of 298,886 patients with isolated foot or ankle fractures were identified, of which 1,661 (0.56%) had VTE in the 90 days following fracture. In terms of timing, 27.3% occurred in the first week, and 49.8% occurred in the first three weeks. Independent risk factors for VTE included (in decreasing order):prior VTE (odd ratio [OR] = 25.44), factor V Leiden (OR = 24.34), active cancer (OR = 1.84), specific fracture relative to metatarsal fracture (multiple fractures [OR: 1.51], ankle fracture [OR = 1.51], and calcaneus fracture [OR = 1.24]), surgical treatment (OR = 1.41), male sex (OR = 1.19), greater Elixhauser index (OR = 1.05), and increasing age (OR:1.05 per decade) (p<0.05 for each).

CONCLUSIONS

The present study found that, although only 0.56% of isolated foot and ankle fractures had a VTE within ninety days. Defined risk factors, such as Factor V Leiden, prior VTE, surgical treatment, active cancer, specific fracture patterns, and surgical treatment significantly affected the odds of their occurrence.

Postoperative bleeding complications in patients with hemophilia undergoing major orthopedic surgery: A prospective multicenter observational study

BACKGROUND

Persons with hemophilia (PWH) are at risk for chronic hemophilic arthropathy (HA). Joint replacement surgery may be used to relieve intractable pain and/or restore joint function.

OBJECTIVES

This multicenter, prospective, observational cohort study evaluated the rate of bleeding during the postoperative period after total hip (THA) or knee arthroplasty (TKA).

PATIENTS/METHODS

We included PWH of any severity ≥18 years of age who were undergoing THA or TKA. Clinical decisions were made at the discretion of the treating physician according to local standards of care. Clinical data were prospectively recorded. Major bleeding was defined as bleeding in a critical site, bleeding that resulted in either a 2 g/dl or greater decrease in hemoglobin during any 24-h period, or transfusion of two or more units of packed red blood cells.

RESULTS

One hundred thirty-one procedures (98 TKA and 33 THA) were performed, 39 (29.8%) of which were complicated by major bleeding, including 46% of THA and 25% of TKA. The risk of major bleeding was increased in THA compared to TKA (OR 2.50, p = .05), and by the presence of an inhibitor (OR 4.29, p = .04), increased BMI (OR 4.49 and 6.09 for overweight and obese, respectively, compared to normal BMI, each p < .01), and non-use of an antifibrinolytic medication (OR 3.00, p = .03). Neither continuous clotting factor infusion (versus bolus infusion) nor pharmacologic thromboprophylaxis were associated with bleeding risk.

CONCLUSIONS

The bleeding risk remains substantial after THA and TKA in PWH, despite factor replacement. Use of antifibrinolytic medications is associated with decreased risk.

Low incidence of clinically relevant bleeding complications after fast-track arthroplasty: a register study of 8,511 arthroplasties

BACKGROUND AND PURPOSE

Fast-track total joint replacement (TJR) has become increasingly common. Routine thromboprophylaxis for pulmonary embolism and deep venous thrombosis prevention lasts from 2 to 5 weeks. This retrospective registry study focused on clinically relevant bleeding complications 90 days after fast-track primary TJR.

PATIENTS AND METHODS

All primary fast-track total hip (THA) and knee arthroplasties (TKA) performed between 2015 and 2016 were extracted from the Finnish Arthroplasty Register and Finnish Hospital Discharge Register. Type of arthroplasty and indication for the operation were combined with diagnoses of clinically relevant bleeding complications within 90 days of surgery. The incidence of these bleedings was the primary outcome measure.

RESULTS

Of the total of 8,511 patients (mean age 67 years (SD 10); 60% female), 45% underwent unilateral THA, 52% unilateral TKA, and 3% bilateral TKA. The incidence of clinically relevant bleeding complications within 90 days was 1% (95% CI 0.8-1.3). No difference was observed in bleeding incidence between the groups. The 87 bleedings comprised 57 operative site bleedings, 17 gastrointestinal bleedings, 6 intracranial non-traumatic bleedings, 5 bleedings from the nose or another undetermined site, and 2 intraocular bleedings. 1 death due to intracranial bleeding was recorded, and hence clinically relevant bleeding-specific 90-day mortality was 0.01%.

INTERPRETATION

The incidence of clinically relevant bleeding complications was low. However, they cause patient discomfort, increase the use of healthcare services, and can be life-threatening and even fatal.

Equivalent VTE rates after total joint arthroplasty using thromboprophylaxis with aspirin versus potent anticoagulants: retrospective analysis of 4562 cases across a diverse healthcare system

BACKGROUND

Guidelines support aspirin thromboprophylaxis for primary total hip and knee arthroplasty (THA and TKA) but supporting evidence has come from high volume centers and the practice remains controversial.

METHODS

We studied 4562 Medicare patients who underwent elective primary THA (1736, 38.1%) or TKA (2826, 61.9%) at 9 diverse hospitals. Thirty-day claims data were combined with data from the health system's electronic medical records to compare rates of venous thromboembolism (VTE) between patients who received prophylaxis with: (1) aspirin alone (47.3%), (2) a single, potent anticoagulant (29%), (3) antiplatelet agents other than aspirin or multiple anticoagulants (21.5%), or (4) low-dose subcutaneous unfractionated heparin or no anticoagulation (2.2%). Sub-analyses separately evaluating THA, TKA and cases from lower volume hospitals (n = 975) were performed.

RESULTS

The 30-day VTE incidence was 0.6% (29/4562). VTE rates were equal in patients receiving aspirin and those receiving a single potent anticoagulant (0.5% in both groups). Patients with VTE were significantly older than patients without VTE (mean 76.5 vs. 73.1 years, P = 0.04). VTE rate did not associate with sex or hospital case volume. On bivariate analysis considering age, aspirin did not associate with greater VTE risk compared to a single potent anticoagulant (OR = 2.1, CI = 0.7-6.3) with the numbers available. Odds of VTE were increased with use of subcutaneous heparin or no anticoagulant (OR = 6.4, CI = 1.2-35.6) and with multiple anticoagulants (OR = 3.6, CI = 1.1-11.2). THA and TKA demonstrated similar rates of VTE (0.5% vs. 0.7%, respectively, P = 0.43). Of 975 cases done at lower volume hospitals, 387 received aspirin, none of whom developed VTE.

CONCLUSIONS

This study provides further support for aspirin as an effective form of pharmacological VTE prophylaxis after total joint arthroplasty in the setting of a multi-modal regimen using 30-day outcomes. VTE occurred in 0.7% of primary joint arthroplasties. Aspirin prophylaxis did not associate with greater VTE risk compared to potent anticoagulants in the total population or at lower volume hospitals.

Thromboembolic and bleeding complications following primary total knee arthroplasty : a Danish nationwide cohort study

AIMS

The aim of this study is to compare the effectiveness and safety of thromboprophylactic treatments in patients undergoing primary total knee arthroplasty (TKA).

METHODS

Using nationwide medical registries, we identified patients with a primary TKA performed in Denmark between 1 January 2013 and 31 December 2018 who received thromboprophylactic treatment. We examined the 90-day risk of venous thromboembolism (VTE), major bleeding, and all-cause mortality following surgery. We used a Cox regression model to compute hazard ratios (HRs) with 95% confidence intervals (CIs) for each outcome, pairwise comparing treatment with dalteparin or dabigatran with rivaroxaban as the reference. The HRs were both computed using a multivariable and a propensity score matched analysis.

RESULTS

We identified 27,736 primary TKA patients who received thromboprophylactic treatment (rivaroxaban (n = 18,846); dalteparin (n = 5,767); dabigatran (n = 1,443); tinzaparin (n = 1,372); and enoxaparin (n = 308)). In the adjusted multivariable analysis and compared with rivaroxaban, treatment with dalteparin (HR 0.68 (95% CI 0.49 to 0.92)) or dabigatran (HR 0.31 (95% CI 0.13 to 0.70)) was associated with a decreased risk of VTE. No statistically significant differences were observed for major bleeding or all-cause mortality. The propensity score matched analysis yielded similar results.

CONCLUSION

Treatment with dalteparin or dabigatran was associated with a decreased 90-day risk of VTE following primary TKA surgery compared with treatment with rivaroxaban. Cite this article: Bone Joint J 2021;103-B(10):1571-1577.

Effectiveness of apixaban versus enoxaparin in preventing wound complications and deep venous thrombosis following total knee replacement surgery: A retrospective study

BACKGROUND

Enoxaparin, a thromboprophylactic drug that is widely used for preventing deep venous thrombosis (DVT) and surgical wound complications after total knee replacement surgery, can only be administered subcutaneously. Apixaban, a novel factor Xa inhibitor that could be comparable to enoxaparin, is an oral formulation and thus would be easier to manage.

OBJECTIVE

To compare the thromboprophylactic effectiveness of apixaban and enoxaparin in patients receiving total knee replacements.

METHODS

In this retrospective, single-institution study, the records of 200 patients who underwent elective total knee replacement surgery were reviewed. Of those, 120 patients had received enoxaparin 4000 IU daily (initiated 6 hours before surgery), whereas 80 had received apixaban 2.5 mg twice daily (initiated 12 hours after surgery), for 21 days. All patients were examined for major and minor surgical wound complications and DVT incidence during their hospital stay and 7-21 days after surgery.

RESULTS

No statistically significant differences (P ≥ .005) were found between the apixaban and enoxaparin groups with regard to minor and major surgical wound complications and DVT incidence. Patients in both groups were comparable in terms of age, hospital stay, and required blood transfusion units. Two enoxaparin-treated patients and one apixaban-treated patient developed DVT (1.5%) during the study period.

CONCLUSION

Oral apixaban is an effective alternative to enoxaparin as a thromboprophylactic drug for patients undergoing elective total knee replacement surgery.

Bleeding risk assessment for venous thromboembolism prophylaxis

Venous thromboembolism (VTE) is one of the main preventable causes of morbidity and mortality in hospitalized patients and fatal pulmonary embolism (PE) may be its first manifestation. Several national and international guidelines recommend using risk assessment models for prescription of VTE prophylaxis in hospitalized patients. Despite evidence and guidelines supporting VTE prevention, use of VTE prophylaxis in hospitalized patients remains suboptimal, which may be because of low awareness of the benefits of VTE prophylaxis, but might also reflect fear of bleeding complications in these patients, since this constitutes one of the main reasons for underutilization of thromboprophylaxis worldwide. Bleeding risk assessment is therefore necessary for adequate prophylaxis prescription and should be carried out concurrently with assessment of the risk of thrombosis. The purpose of this review is to highlight the importance of jointly assessing risk of VTE and risk of bleeding in hospitalized patients.

Bleeding complications of thromboprophylaxis with dabigatran, nadroparin or rivaroxaban for 6 weeks after total knee arthroplasty surgery: a randomised pilot study

OBJECTIVES

For the non-vitamin-K oral anticoagulants, data on bleeding when used for 42 days as thromboprophylaxis after total knee arthroplasty (TKA) are scarce. This pilot study assessed feasibility of a multicentre randomised clinical trial to evaluate major and clinically relevant non-major bleeding during 42-day use of dabigatran, nadroparin and rivaroxaban after TKA.

PATIENTS AND METHODS

In 70 weeks, between July 2012 and November 2013, 198 TKA patients were screened for eligibility in the Martini Hospital (Groningen, the Netherlands). Patients were randomly assigned to dabigatran (n=45), nadroparin (n=45) or rivaroxaban (n=48). The primary outcome was the combined endpoint of major bleeding and clinically relevant non-major bleeding. Secondary endpoints of this study were the occurrence of clinical venous thromboembolism (VTE) (pulmonary embolism or deep venous thrombosis), compliance, duration of hospital stay, rehospitalisation, adverse events and Knee Injury and Osteoarthritis Outcome Score (KOOS).

RESULTS

The primary outcome was observed in 33.3% (95% CI 20.0% to 49.0%), 24.4% (95% CI 12.9% to 39.5%) and 27.1% (95% CI 15.3% to 41.8%) of patients who received dabigatran, nadroparin or rivaroxaban, respectively (p=0.67). Major bleeding was found in two patients who received nadroparin (p=0.21). Clinically relevant non-major bleeding was observed in 33.3% (95% CI 20.0% to 49.0%), 22.2% (95% CI 11.2% to 37.1%) and 27.1% (95% CI 15.3% to 41.8%) for dabigatran, nadroparin and rivaroxaban, respectively (p=0.51). Wound haematoma was the most observed bleeding event. VTE was found in one patient who received dabigatran (p=0.65). The presurgery and postsurgery KOOS qQuestionnaires were available for 32 (71%), 35 (77%) and 35 (73%) patients for dabigatran, nadroparin and rivaroxaban, respectively. KOOS was highly variable, and no significant difference between treatment groups in mean improvement was observed.

CONCLUSIONS

A multicentre clinical trial may be feasible. However, investments will be substantial. No differences in major and clinically relevant non-major bleeding events were found between dabigatran, nadroparin and rivaroxaban during 42 days after TKA. KOOS may not be suitable to detect functional loss due to bleeding.

TRIAL REGISTRATION NUMBER

NCT01431456.

Perioperative Venous Thromboembolism Prophylaxis

Venous thromboembolism (VTE) is a preventable cause of postoperative morbidity and mortality; however, audits suggest that the use of thromboprophylaxis is underused. In this review, we describe our approach to prevention of postoperative VTE and provide guidance on how to formulate an optimal VTE prophylaxis plan. We recommend that all patients undergo thrombosis- and bleeding-risk assessment as part of their preoperative evaluation. The risk of thrombosis can be estimated based on patient- and procedure-specific factors, using validated risk-assessment models such as the Caprini score. There are no validated models to predict perioperative bleeding; however, several risk factors have been proposed. Patients should ambulate early and frequently after surgery. We recommend no additional prophylaxis in patients at very low risk of VTE (Caprini score 0). Patients at low risk of VTE (Caprini 1 to 2) are recommended to receive either mechanical or pharmacological prophylaxis. Patients at moderate (Caprini 3 to 4) to high risk of VTE (Caprini ≥5) are recommended pharmacological prophylaxis either alone or combined with mechanical prophylaxis. Patients at high risk of bleeding should receive mechanical prophylaxis until their risk of bleeding is reduced and pharmacological prophylaxis can be reconsidered. Populations for which the Caprini score has not been validated (such as orthopedic surgery) are recommended prophylaxis based on individual and procedure-specific risk factors. Prophylaxis is typically continued until the patient is ambulatory or until hospital dismissal; however, longer durations can be considered in certain circumstances (high-risk patients undergoing malignant abdominopelvic operations, bariatric operations, and certain orthopedic operations).

Bleeding Independently associated with Mortality after noncardiac Surgery (BIMS): an international prospective cohort study establishing diagnostic criteria and prognostic importance

BACKGROUND

We aimed to establish diagnostic criteria for bleeding independently associated with mortality after noncardiac surgery (BIMS) defined as bleeding during or within 30 days after noncardiac surgery that is independently associated with mortality within 30 days of surgery, and to estimate the proportion of 30-day postoperative mortality potentially attributable to BIMS.

METHODS

This was a prospective cohort study of participants ≥45 yr old having inpatient noncardiac surgery at 12 academic hospitals in eight countries between 2007 and 2011. Cox proportional hazards models evaluated the adjusted relationship between candidate diagnostic criteria for BIMS and all-cause mortality within 30 days of surgery.

RESULTS

Of 16 079 participants, 2.0% (315) died and 36.1% (5810) met predefined screening criteria for bleeding. Based on independent association with 30-day mortality, BIMS was identified as bleeding leading to a postoperative haemoglobin <70 g L^-1, transfusion of ≥1 unit of red blood cells, or that was judged to be the cause of death. Bleeding independently associated with mortality after noncardiac surgery occurred in 17.3% of patients (2782). Death occurred in 5.8% of patients with BIMS (161/2782), 1.3% (39/3028) who met bleeding screening criteria but not BIMS criteria, and 1.1% (115/10 269) without bleeding. BIMS was associated with mortality (adjusted hazard ratio: 1.87; 95% confidence interval: 1.42-2.47). We estimated the proportion of 30-day postoperative deaths potentially attributable to BIMS to be 20.1-31.9%.

CONCLUSIONS

Bleeding independently associated with mortality after noncardiac surgery (BIMS), defined as bleeding that leads to a postoperative haemoglobin <70 g L^-1, blood transfusion, or that is judged to be the cause of death, is common and may account for a quarter of deaths after noncardiac surgery.

CLINICAL TRIAL REGISTRATION

NCT00512109.

Postoperative Thromboprophylaxis With New Oral Anticoagulants is Superior to LMWH in Hip Arthroplasty Surgery: Findings from the Swedish Registry

BACKGROUND

Although the use of thromboprophylaxis is well established, there is no consensus on the preferred thromboprophylaxis regimen after THA; large, population-based studies offer an opportunity to examine this problem in a robust way that can complement results from randomized trials.

QUESTIONS/PURPOSES

Using data from a large national registry, we asked: (1) Is there any difference between low-molecular weight heparin (LMWH) and new oral anticoagulants in preventing symptomatic deep vein thrombosis (DVT) and pulmonary embolism (PE), after THA? (2) Are there any differences in safety parameters, such as bleeding, reoperations and mortality, between LMWH and new oral anticoagulants?

METHODS

Between 2008 and 2012, 78,066 THAs were performed in Sweden. This study evaluated 32,663 (42%) of them, selected through the merger of several national registries. These patients underwent unilateral THA due to primary osteoarthritis. They had not experienced any venous thromboembolic events 5 years before the index operation and were not prescribed potent antithrombotic agents, of any type, in the 6 months before the index operation. Additionally, their postoperative thromboprophylaxis was confirmed in a national registry by purchase of prescribed medications. We divided the cohort into two groups: those patients who received new oral anticoagulants (5752, 18%) and those who received LMWH (26,881, 82%) as postoperative thromboprophylaxis. Our primary endpoints were the frequencies of symptomatic DVT and symptomatic PE within 3 months of surgery. Our secondary comparison was a between-group comparison of bleeding (by way of diagnostic coding), reoperation, and mortality within 3 months of surgery. Odds ratios (OR) are presented with 95% confidence intervals (CIs) as pooled results for the two groups after adjustment for duration of thromboprophylaxis (short or extended for at least 28 days), year of the index operation, Elixhauser comorbidity index, sex, age and previous treatment with platelet aggregation inhibitors.

RESULTS

The risk of symptomatic DVT was lower in the group that received new oral anticoagulants than the group that received LMWH (0.3% versus 0.6%, OR, 0.47; 95% CI, 0.27-0.76; p = 0.026). The risk of symptomatic PE was lower in the group that received new oral anticoagulants than the group that received LMWH (0.1% versus 0.4%, OR, 0.36; 95% CI, 0.16-0.69; p = 0.005). There was no difference in the risk of bleeding (by way of diagnostic coding) (OR, 1.03; 95% CI, 0.82-1.28; p = 0.688), reoperation (OR, 1.02; 95% CI, 0.71-1.44; p = 0.860) or mortality (OR, 0.83; 95% CI, 0.31-1.88; p = 0.883) between groups.

CONCLUSIONS

New oral anticoagulants were associated with a lower risk of symptomatic DVT and symptomatic PE in this large, registry study, and we observed no differences in the risk of bleeding, reoperation, or death between the groups. Although we were able to control for a number of potential confounding variables, we cannot ascertain the indications that drove the prescription decisions in this setting, and there were important between-group differences in terms of duration of thromboprophylaxis (new oral anticoagulants generally were used for a longer period of time after surgery). Future studies, preferably large randomized trials with pragmatic inclusion criteria, to analyze symptomatic DVT, symptomatic PE and death are needed to confirm or refute our findings.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Landmark trials in thrombotic vascular disease: a critical appraisal of potential practice-changing trials in 2016-2017

Recent years have witnessed an onslaught of large, multicenter, randomized controlled trials evaluating the prevention and management of thrombotic vascular diseases. While these trials have applied rigorous methodology to pragmatic and clinically relevant questions, several important gaps in knowledge remain. In this review, we critically appraise landmark studies in thrombosis published between 2016 and 2017 that address several ongoing areas of clinical uncertainty. Specifically, we review the role of endovascular therapy in the prevention of post-thrombotic syndrome following acute lower limb deep vein thrombosis (DVT) (ATTRACT trial), the efficacy of edoxaban as the first direct oral anticoagulant used for the treatment of cancer-associated thrombosis (HOKUSAI VTE-Cancer study), whether aspirin can be considered for thromboprophylaxis post-major orthopedic surgery (EPCAT-2 trial), and the need for anticoagulant therapy for treatment of isolated distal DVT (CACTUS trial). Using illustrative cases, we highlight the applicability of these trials to current practice and emphasize the unanswered questions that remain.

Low-molecular-weight heparin for hip fracture patients treated with osteosynthesis: should thromboprophylaxis start before or after surgery? An observational study of 45,913 hip fractures reported to the Norwegian Hip Fracture Register

Background and purpose - Controversies exist regarding thromboprophylaxis in orthopedic surgery. We studied whether the thromboprophylaxis in hip fracture patients treated with osteosynthesis should start preoperatively or postoperatively. Data were extracted from the nationwide Norwegian Hip Fracture Register (NHFR). The risks of postoperative deaths, reoperations, and intraoperative bleeding were studied within 6 months after surgery. Patients and methods - After each operation for hip fracture in Norway the surgeon reports information on the patient, the fracture, and the operation to the NHFR. Cox regression analyses were performed with adjustments for age group, ASA score, sex, duration of surgery, and year of surgery. During the period 2005-2016, 96,599 hip fractures were reported to the register. Only osteosyntheses where low-molecular-weight heparin (LMWH) were given and with known information on preoperative start of the prophylaxis were included in the analyses. Dalteparin and enoxaparin were used in 58% and 42% of the operations respectively (n = 45,913). Results - Mortality (RR =1.01, 95% CI 0.97-1.06) and risk of reoperation (RR =0.99, CI 0.90-1.08) were similar comparing preoperative and postoperative start of LMWH. Postoperative start reduced the risk of intraoperative bleeding complications compared with preoperative start (RR =0.67, CI 0.51-0.90). Interpretation - The initiation of LMWH did not influence the mortality or the risk of reoperation in hip fracture patients treated with osteosynthesis. Postoperative start of LMWH could possibly decrease the risk of intraoperative bleeding.

Cost-Utility Analysis of Venous Thromboembolism Prophylaxis Strategies for People Undergoing Elective Total Hip and Total Knee Replacement Surgeries in the English National Health Service

Background: Major orthopedic surgery, such as elective total hip replacement (eTHR) and elective total knee replacement (eTKR), are associated with a higher risk of venous thromboembolism (VTE) than other surgical procedures. Little is known, however, about the cost-effectiveness of VTE prophylaxis strategies in people undergoing these procedures. Aim: The aim of this work was to assess the cost-effectiveness of these strategies from the English National Health Service perspective to inform NICE guideline (NG89) recommendations. Materials and Methods: Cost-utility analysis, using decision modeling, was undertaken to compare 15 VTE prophylaxis strategies for eTHR and 12 for eTKR, in addition to "no prophylaxis" strategy. The analysis complied with the NICE Reference Case. Structure and assumptions were agreed with the guideline committee. Incremental net monetary benefit (INMB) was calculated, vs. the model comparator (LMWH+ antiembolism stockings), at a threshold of £20,000/quality-adjusted life-year (QALY) gained. The model was run probabilistically. Deterministic sensitivity analyses (SAs) were undertaken to assess the robustness of the results. Results: The most cost-effective strategies were LMWH for 10 days followed by aspirin for 28 days (INMB = £530 [95% CI: -£784 to £1,103], probability of being most cost-effective = 72%) for eTHR, and foot pump (INMB = £353 [95% CI: -£101 to £665]; probability of being most cost-effective = 18%) for eTKR. There was considerable uncertainty regarding the cost-effectiveness ranking in the eTKR analysis. The results were robust to change in all SAs. Conclusions: For eTHR, LMWH (standard dose) for 10 days followed by aspirin for 28 days is the most cost-effective VTE prophylaxis strategy. For eTKR, the results are highly uncertain but foot pump appeared to be the most cost-effective strategy, followed closely by aspirin (low dose). Future research should focus on assessing cost-effectiveness of VTE prophylaxis in the eTKR population.

Postoperative Joint Replacement Complications in Swedish Patients With a Family History of Venous Thromboembolism

IMPORTANCE

The associations of a family history of venous thromboembolism (FH-VTE) with postoperative venous thromboembolism (VTE) and major bleeding after joint replacement surgical procedures are unknown.

OBJECTIVE

To determine the risk of VTE and major bleeding in patients after primary hip or knee replacement surgical procedures.

DESIGN, SETTING, AND PARTICIPANTS

Cohort study using nationwide population-based databases of Swedish patients without a history of VTE who underwent joint replacement surgical procedures. Patients who had primary hip or knee replacement surgical procedures between July 1, 2005, and August 31, 2012, were identified. Patients born after 1931 without previous VTE were identified in the Swedish Multi-Generation Register. Only individuals with at least 1 parent and 1 full sibling alive between 1964 and the date for the surgical procedure were included. The data analysis was performed from September 1, 2017, to June 15, 2018.

EXPOSURES

Family history of VTE in a parent and/or a full sibling before the date of the surgical procedure.

MAIN OUTCOMES AND MEASURES

Venous thromboembolism and major bleeding within 90 days of the surgical procedure.

RESULTS

Of 69 505 study participants, 37 989 (54.7%) were women, and the median (interquartile range) age at the date of discharge was 65 (59-70) years. A total of 803 of 69 505 (1.2%) patients experienced postoperative VTE and 1285 (1.8%) experienced major bleeding. The cumulative VTE risk for those with FH-VTE was 231 of 15 858 (1.5%) and for those without an FH-VTE was 572 of 53 647 (1.1%) (P < .001). The cumulative bleeding risk for those with FH-VTE was 261 of 15 858 (1.6%) and for those without an FH-VTE was 1024 of 53 647 (1.9%) (P = .03). There was an association of patients with an FH-VTE who had increased VTE risk (adjusted hazard ratio [HR], 1.36; 95% CI, 1.17-1.59) and reduced bleeding risk (adjusted HR, 0.84; 95% CI, 0.74-0.97). There was an interaction between time after discharge and FH-VTE regarding VTE and major bleeding. An FH-VTE was not associated with VTE after discharge during the first week (HR, 1.13; 95% CI, 0.86-1.49). After 7 days from discharge, FH-VTE was associated with VTE (HR, 1.49; 95% CI, 1.24-1.79). An FH-VTE reduced major bleeding risk during the first 7 days after discharge (HR, 0.78; 95% CI, 0.66-0.91) but not thereafter (HR, 1.10; 95% CI, 0.84-1.44). Postoperative VTE heritability (SE) was 20% (6%).

CONCLUSIONS AND RELEVANCE

Familial and most likely genetic factors appear to affect VTE and major bleeding risk following hip and knee replacement surgical procedures. Prolonged VTE prophylaxis might be beneficial in predisposed individuals. There may be a possible evolutionary advantage of prothrombotic genes protecting against traumatic bleeding.

Effect of oral factor Xa inhibitor and low-molecular-weight heparin on surgical complications following total hip arthroplasty

This prospective study was conducted to report the effect of oral factor Xa inhibitor and low-molecular-weight heparin (LMWH) on surgical complications following total hip arthroplasty (THA). The patients with an age < 60 years were randomly assigned to three groups (rivaroxaban, enoxaparin, and placebo) and the patients with an age ≥ 60 years were assigned to two groups (rivaroxaban and enoxaparin). All drug regimens started at 12 hours postoperatively and continued for two weeks after surgery. Primary measure outcome was major surgical wound complications defined as haematoma requiring any intervention, superficial wound infection, deep periprosthetic infection, and increased wound bleeding. Secondary measured outcome included minor surgical complications (swelling, drainage, erythema, and oozing), organ bleeding, and venous thromboembolic (VTE) events. A total of 184 patients aged < 60 years and 167 patients aged ≥ 60 years were included as the analysis population per group. Up to 14 days after surgery, the overall incidence of major surgical complications associated with thromboprophylaxis was 6.5 % (58/886). There were no significant differences in the rate of major surgical complications among all the three groups of the patients aged < 60 years and between two groups of the patients aged ≥ 60 years. For the patients aged < 60 years, wound oozing continued significantly longer in the pharmacological group than in the placebo group, but wound infection did not occur in any case. The VTE events were similar in all the groups.

Klinische Studien zu neuen direkten oralen Antikoagulanzien

Um die Wirksamkeit und Verträglichkeit neuer direkter oraler Antikoagulanzien (DOAK) zu vergleichen, müssten idealerweise eine direkte Gegenüberstellung der Substanzen in klinischen Studien durchgeführt werden. Auf Grund des logistischen und finanziellen Aufwandes wird dies aber in absehbarer Zeit nicht geschehen. Indirekte Vergleiche, auch Netzwerkanalysen (NMA) genannt, lassen sich mit den vorliegenden Studien zwischen den DOAKs vornehmen. In der postoperativen Phase nach Knie- und Hüftgelenkersatz und bei Patienten mit Vorhofflimmern sind derzeit diese Vergleich möglich. Indirekte Vergleiche sind jedoch auch mit Einschränkungen behaftet.

Diese Arbeit gibt eine Übersicht der aktuell vorliegenden NMAs und versucht, deren Ergebnisse mit der Pharmakologie der DOAKs und den methodischen Problemen von NMAs zu beleuchten.

Interpretation of endpoints in a network meta-analysis of new oral anticoagulants following total hip or total knee replacement surgery

New oral anticoagulant (NOAC) regimens [dabigatran 150 mg (D150) and 220 mg (D220), rivaroxaban 10 mg (R20), and apixaban 2.5 mg bid (A5)] were effective and safe compared to enoxaparin for the prevention of venous thromboembolism (VTE) following elective total knee (TKR) or hip replacement (THR) surgery. First a cluster analysis was used to identify homogeneous studies for the trial programs of each NOAC. Second, only studies reporting VTE and VTE-related death, major bleeding, and mortality were included. The odds ratio (OR) and 95% confidence interval (CI) were calculated for each NOAC regimen versus the comparator. Third, these data were used for the indirect comparison between NOACs. Cluster analysis identified duration of treatment (10 ± 5 and 34 ± 5 days) as the only homogeneous parameter across all NOAC programs (p>0.05) except for A5 and VTE over 10 ± 5 days (analysis not performed). The results of the calculated OR and 95% CI of the four NOAC regimens over 10 ± 5 and 34 ± 5 days showed inferiority of D150 and D220 compared to R10 for VTE (p<0.01, p<0.001). Comparisons of major bleeding and mortality were not different for all indirect comparisons. Despite the lack of standard definitions for VTE and bleeding outcomes, cluster analysis seems to be an appropriate tool to identify homogeneity across trial programs and to perform an indirect comparison for NOACs for prevention of VTE following TKR and THR surgery.

Benefit-to-harm ratio of thromboprophylaxis for patients undergoing major orthopaedic surgery

Surgeons consider the benefit-to-harm ratio when making decisions regarding the use of anticoagulant venous thromboembolism (VTE) prophylaxis. We evaluated the benefit-to-harm ratio of the use of newer anticoagulants as thromboprophylaxis in patients undergoing major orthopaedic surgery using the likelihood of being helped or harmed (LHH), and assessed the effects of variation in the definition of major bleeding on the results. A systematic literature search was performed to identify phase II and phase III studies that compared regulatory authority-approved newer anticoagulants to the low-molecularweight heparin enoxaparin in patients undergoing major orthopaedic surgery. Analysis of outcomes data estimated the clinical benefit (number-needed-to-treat [NNT] to prevent one symptomatic VTE) and clinical harm (number-needed-to-harm [NNH] or the NNT to cause one major bleeding event) of therapies. We estimated each trial’s benefitto-harm ratio from NNT and NNH values, and expressed this as LHH = (1/NNT)/(1/NNH) = NNH/NNT. Based on reporting of efficacy and safety outcomes, most studies favoured enoxaparin over fondaparinux, and rivaroxaban over enoxaparin. However, when using the LHH metric, most trials favoured enoxaparin over both fondaparinux and rivaroxaban when they included surgical-site bleeding that did not require reoperation in the definition of major bleeding. The exclusion of bleeding at surgical site which did not require reoperation shifted the benefit-to-harm ratio in favour of the newer agents. Variations in the definitions of major bleeding may change the benefit-to-harm ratio and subsequently affect its interpretation. Clinical trials should attempt to improve the consistency of major bleeding reporting.

Prospective, multicenter study of postoperative deep-vein thrombosis in patients with haemophilia undergoing major orthopaedic surgery

Perioperative clotting factor replacement is administered to reverse the inherent haemostatic defect in persons with haemophilia (PWH), potentially increasing their risk for developing venous thromboembolism (VTE) postoperatively. It was our objective to determine the prevalence of VTE in PWH undergoing total hip or knee arthroplasty (THA, TKA). Patients with haemophilia A or B who underwent THA or TKA were enrolled in this prospective, multicentre observational cohort study. Lower extremity venous duplex ultrasound was performed prior to surgery and 4–6 weeks after surgery. Eleven centres enrolled 51 subjects, 46 of whom completed the study. Six subjects (13.0 %) were treated with bypass agents perioperatively; the remaining 40 subjects received factor VIII or IX replacement. Intermittent pneumatic compression devices were utilised postoperatively in 23 subjects (50 %), and four subjects (8.7 %) also received low-molecular-weight heparin prophylaxis. One subject (2.2 %) with moderate haemophilia A was diagnosed with symptomatic distal deep-vein thrombosis (DVT) on day 6 following TKA. One subject (2.2 %) with severe haemophilia A was diagnosed with pulmonary embolism on day 9 following bilateral TKA. No subjects had asymptomatic DVT. Eighteen subjects (39.1 %) had major bleeding, and three subjects (6.5 %) experienced minor bleeding. The observed prevalence of ultrasound-detectable, asymptomatic DVT in PWH following TKA or THA in this study was low, but the incidence of symptomatic VTE (4.3 %, 95 % CI, 0.5–14.8 %) appeared similar to the estimated incidence in the general population without thromboprophylaxis.

Evaluation of rivaroxaban use in patients with gynecologic malignancies at an academic medical center: A pilot study

BACKGROUND

Patients with gynecologic malignancies are at an increased risk for venous thromboembolism. National guidelines recommend treatment of an acute venous thromboembolism with low molecular weight heparin for 5-10 days followed by long-term secondary prophylaxis with low molecular weight heparin for at least six months. Non-vitamin K oral anticoagulants are not currently recommended to be used in cancer patients for the management of venous thromboembolism because robust data on their efficacy and safety have yet to become available in cancer patients. The objectives of this study were to determine the proportion of gynecologic oncology patients with venous thromboembolism using rivaroxaban compared to warfarin or low molecular weight heparin as well as compare the safety and efficacy of these anticoagulants.

METHODS

This study was a retrospective pilot analysis of adult patients with gynecologic malignancies who received either rivaroxaban, warfarin or low molecular weight heparin for treatment of venous thromboembolism at Augusta University Medical Center from 1 July 2013 to 30 June 2015. Statistical comparisons between the enoxaparin and rivaroxaban group were made using T-tests and Chi-square or Fisher's exact tests, where appropriate.

RESULTS

Out of the 49 patients, 37% (18) patients were on rivaroxaban, 53% (26) on enoxaparin, and 10% (5) on warfarin. Only one patient (4%) in the enoxaparin group experienced a recurrent deep vein thrombosis while there were no cases of recurrent venous thromboembolism in the rivaroxaban and warfarin group. The incidence of major bleeding was 17% (n = 2), 20% (n = 1), and 8% (n = 2) in patients receiving rivaroxaban, enoxaparin, and warfarin, respectively. The rate of switching to a different anticoagulant than originally prescribed was 42% (n = 14) in the enoxaparin arm, and 5.5% (n = 1) in the rivaroxaban arm.

CONCLUSION

A high proportion of our gynecologic oncology patients received rivaroxaban for the management of venous thromboembolism. The sample size of this pilot analysis was too small to draw any conclusions regarding efficacy and safety of rivaroxaban compared with enoxaparin and warfarin. High rate of rivaroxaban use in gynecologic oncology patients at our institution highlights the need for larger, well-designed randomized controlled trials to confirm the safety and efficacy of its use in this population.

Comparative efficacy and safety of anticoagulants for prevention of venous thromboembolism after hip and knee arthroplasty

Background and purpose - New oral anticoagulants have been developed to prevent venous thromboembolism (VTE) after knee or hip arthroplasty. Although there have been several network meta-analyses (NMA) to compare different regimens, an NMA including 2 different enoxaparin doses and edoxaban has not been performed. Methods - Standard NMA for fondaparinux, dabigatran, rivaroxaban, apixaban, edoxaban, and enoxaparin was performed. Outcome variables included a composite of total VTE and major/clinically relevant bleeding. The rank probabilities of each treatment outcome were summarized by the surface under the cumulative ranking curve. Results - Fondaparinux, rivaroxaban, and apixaban were associated with a reduced risk of VTE compared with enoxaparin, while dabigatran was not. None of these 3 drugs increased bleeding compared with enoxaparin 30 mg twice daily. However, fondaparinux and rivaroxaban increased bleeding compared with enoxaparin 40 mg once daily, while apixaban did not. Apixaban was even associated with decreased major/clinically relevant bleeding compared with enoxaparin 30 mg twice daily or 40 mg once daily. When edoxaban was included in the NMA, edoxaban decreased VTE and did not increase bleeding compared with enoxaparin. Interpretation - A higher efficacy of fondaparinux and rivaroxaban compared with enoxaparin was associated with increased bleeding tendency, while apixaban was superior to enoxaparin regarding both efficacy and safety. A clustered ranking plot showed that apixaban might be the most preferred regarding efficacy and safety. However, our results were driven by indirect statistical inference and were limited by the heterogeneity of the bleeding outcome definitions, drug initiation and continuation, and different surgery types.

Similar Clinical Outcomes with Preoperative and Postoperative Start of Thromboprophylaxis in THA: A Register-based Study

BACKGROUND

Elective THA is associated with a high risk of thromboembolic events. Although these events may be less common now than they were in the past, they can be serious, and most patients undergoing the procedure therefore still receive thromboprophylaxis. However, controversy remains regarding whether to begin thromboprophylaxis before THA or after to best balance the risks of clotting and bleeding.

QUESTIONS/PURPOSES

We asked the following questions: (1) Is there a difference in bleeding events with pre- versus postoperative thromboprophylaxis? (2) Is there a difference in thromboembolic episodes after THA between the two regimens? (3) How do the two approaches of thromboprophylaxis influence mortality, readmissions, and other complications?

METHODS

We used a population-based followup design with predefined data based on international health codification to assess clinical effects of LMWH prophylaxis initiated before or after THA. We took data limited to primary THAs done in Norway between January 1, 2008, and December 31, 2011, from the Norwegian Arthroplasty Register and the National Patient Register to have necessary data elements to complete the study. The two registers were merged after identifying patients with their 11-digit personal identification number (Social Security number). We obtained data regarding demographics, administrative and surgical details, and episode histories for prophylaxis-related events within 180 days of surgery. A total of 25,163 patients undergoing THA were included for analysis, and 9977(40%) versus 15,186 (60%) patients received pre- and postoperative LMWH, respectively. We performed statistical adjustment for differences in baseline characteristics using multivariate logistic regression.

RESULTS

After adjustment for age, sex, operation time, year of surgery, and American Society of Anesthesiologists class, we could not show major differences in bleeding events; (odds ratio [OR], 1.04; 95% CI, 0.88-1.22; p = 0.660), thromboembolic episodes; (OR, 1.03; 95% CI, 0.84-1.27; p = 0.786), or other postoperative clinical complications; (OR, 0.86; 95% CI, 0.76-0.99; p = 0.034), with the two regimens. Six-month mortality was similar, (OR, 0.76; 95% CI, 0.56-1.05; p = 0.093), and the readmission rate was higher in the preoperative group; (OR, 0.92; 95% CI, 0.85-0.97; p = 0.016).

CONCLUSIONS

The risk for postoperative complications seems to be comparable whether LMWH prophylaxis is initiated before or after THA. The postoperative approach reduces costs, decreases risks related to neuraxial anesthesia, and facilitates same-day admissions. Methods for individual risk assessment including laboratory tests would be feasible.

LEVEL OF EVIDENCE

Level III, therapeutic study.

A post-marketing assessment of major bleeding in total hip and total knee replacement surgery patients receiving rivaroxaban

BACKGROUND

Rivaroxaban is a novel oral anticoagulant indicated for prophylaxis against deep vein thrombosis and pulmonary embolism in patients undergoing total hip replacement (THR) or total knee replacement (TKR) surgery.

OBJECTIVE

To evaluate major bleeding (MB) in THR/TKR patients receiving post-operative rivaroxaban.

METHODS

Electronic medical records of nearly 10 million US Department of Defense (DoD) beneficiaries were queried from 1 January 2013 through 30 June 2015. Using the validated Cunningham case-finding algorithm, post-surgical MB events in rivaroxaban users were identified and analyzed. The incidence of MB was determined, and descriptive statistics were used to compare patient characteristics and other covariates in those with and without MB. Two additional methods were used to explore and identify bleeding cases that were not considered MB events per the study case-finding algorithm.

RESULTS

A total of 12,429 patients received THR and/or TKR surgery, and were post-operatively prescribed rivaroxaban. Nine patients had MB, yielding an incidence proportion of 0.07% (95% CI 0.02-0.13). The alternative case-finding methods found bleeding incidences of 0.46% and 0.21%, though it is not clear whether these are clinical MB cases, since the alternative methods were not validated.

CONCLUSIONS

The incidence of MB in this retrospective analysis is lower than that observed in the clinical trials of rivaroxaban. Whether this is due to lower real-world MB rates or challenges with case-finding algorithms is unclear.

Prothrombin fragment F1+2 in plasma and urine during total hip arthroplasty

OBJECTIVE

To study the time course and correlation of prothrombin fragment (F1 + 2) in plasma and urine during THA.

METHOD

F1 + 2 concentrations were recorded at four time-points during THA.

RESULTS

F1 + 2 increased during surgery. In contrast to urine, plasma F1 + 2 was temporarily reduced the first postoperative day. At day six, plasma F1 + 2 was significantly elevated indicating on-going thrombin activation, while urine F1 + 2 was normalized.

CONCLUSION

The response in coagulation to operative trauma can be recorded with F1 + 2 both in plasma and urine. We were not able to demonstrate any correlation of F1 + 2 in plasma and urine later in the postoperative period.

Bleeding impacting mortality after noncardiac surgery: a protocol to establish diagnostic criteria, estimate prognostic importance, and develop and validate a prediction guide in an international prospective cohort study

INTRODUCTION

Various definitions of bleeding have been used in perioperative studies without systematic assessment of the diagnostic criteria for their independent association with outcomes important to patients. Our proposed definition of bleeding impacting mortality after noncardiac surgery (BIMS) is bleeding that is independently associated with death during or within 30 days after noncardiac surgery. We describe our analysis plan to sequentially 1) establish the diagnostic criteria for BIMS, 2) estimate the independent contribution of BIMS to 30-day mortality and 3) develop and internally validate a clinical prediction guide to estimate patient-specific risk of BIMS.

METHODS

In the Vascular Events In Noncardiac Surgery Patients Cohort Evaluation (VISION) study, we prospectively collected bleeding data for 16 079 patients aged 45 years or more who had noncardiac inpatient surgery between 2007 and 2011 at 12 centres in 8 countries across 5 continents. We will include bleeding features independently associated with 30-day mortality in the diagnostic criteria for BIMS. Candidate features will include the need for reoperation due to bleeding, the number of units of erythrocytes transfused, the lowest postoperative hemoglobin concentration, and the absolute and relative decrements in hemoglobin concentration from the preoperative value. We will then estimate the incidence of BIMS and its independent association with 30-day mortality. Last, we will construct and internally validate a clinical prediction guide for BIMS.

INTERPRETATION

This study will address an important gap in our knowledge about perioperative bleeding, with implications for the 200 million patients who undergo noncardiac surgery globally every year. Trial registration: ClinicalTrials.gov, no NCT00512109.

The risks of pulmonary embolism and upper gastrointestinal bleeding beyond 35days after total hip replacement for coxarthrosis among middle-aged patients: A cross-over cohort

Prophylactic anticoagulation is recommended up to 35days after total hip replacement (THR). Although several observational studies have assessed the incidence of thrombotic events or bleeding events after THR, the corresponding measures of association have never been studied concomitantly. Here, we evaluated the duration of the elevated risks (relative to the baseline risk) of both venous thromboembolic events and bleeding events after THR for coxarthrosis among middle-aged patients. This was a population-based, cross-over cohort study of data extracted from the French national inpatient database between 2007 and 2013. We included middle-aged patients (aged 45 to 69) having undergone THR for coxarthrosis. We compared the numbers of pulmonary embolisms (PEs) (respectively upper gastrointestinal bleedings (UGIBs)) following the THR with the numbers occurring during three unexposed periods one year later. This enabled us to estimate the odds ratio (OR) [95% confidence interval (CI)] for each of six successive 35-day intervals. The study included 108,099 patients. The ORs for PE were respectively 12.4 (95% CI, 8.6-17.8) (absolute risk difference rate per 100,000 (ARD/100,000)=130) and 5.0 (95% CI, 3.4-7.4) (ARD/100,000=52) for the first two 35-day intervals, and the risk was close to 1 thereafter. The risk of UGIB fell quickly, with an OR of 6.5 (95% CI, 4.6-9.1) (ARD/100,000=83) and 0.8 (95% CI, 0.4-1.6) for the first two 35-day intervals, respectively. The majority of UGIBs occurred during the inpatient stay for THR. Among middle-aged patients, the risk of a PE remains elevated beyond 35days after THR for coxarthrosis, whereas the risk of a UGIB remains elevated for the first 35days only.

Rivaroxaban for thromboprophylaxis after total hip or knee arthroplasty: a meta-analysis with trial sequential analysis of randomized controlled trials

Venous thromboembolism (VTE) is the most widespread severe complication after total hip arthroplasty (THA) and total knee arthroplasty (TKA). We conducted this meta-analysis to further validate the benefits and harms of rivaroxaban use for thromboprophylaxis after THA or TKA. We thoroughly searched PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials. Trial sequential analysis (TSA) was applied to test the robustness of our findings and to obtain a more conservative estimation. Of 316 articles screened, nine studies were included. Compared with enoxaparin, rivaroxaban significantly reduced symptomatic VTE (P = 0.0001) and symptomatic deep vein thrombosis (DVT; P = 0.0001) but not symptomatic pulmonary embolism (P = 0.57). Furthermore, rivaroxaban was not associated with an increase in all-cause mortality, clinically relevant non-major bleeding and postoperative wound infection. However, the findings were accompanied by an increase in major bleeding (P = 0.02). The TSA demonstrated that the cumulative z-curve crossed the traditional boundary but not the trial sequential monitoring boundary and did not reach the required information size for major bleeding. Rivaroxaban was more beneficial than enoxaparin for preventing symptomatic DVT but increased the risk of major bleeding. According to the TSA results, more evidence is needed to verify the risk of major bleeding with rivaroxaban.

Incidence of venous thromboembolism and hemorrhage related safety studies of preoperative anticoagulation therapy in hip fracture patients undergoing surgical treatment: a case-control study

Background

Venous thromboembolism is a common postoperative complication following orthopedic surgeries, with morbid and potentially fatal consequences. Perioperative low-molecular-weight heparin (LMWH) therapy can reduce the incidence of venous thromboembolism, but may also increase the risk of bleeding complications. Current literature reflects the need to balance the improved efficacy of early initiating prophylaxis with increased risk of perioperative bleeding. The purpose of this study was to compare the effectiveness and hemorrhage related safety of preoperative versus postoperative LMWH therapy for prevention of deep venous thrombosis (DVT) and pulmonary embolism (PE) in hip fracture patients.

Methods

We retrospectively evaluated 222 patients who underwent surgical treatment at Peking University People's Hospital between January 2009 and December 2010. Patients were allocated to two groups, receiving either preoperative or postoperative initiation of LMWH therapy for venous thromboembolism prophylaxis. Preoperative anticoagulation therapy was initiated 1–12 days prior to surgery (133 patients), and postoperative anticoagulation therapy was initiated 12 h after completion of surgery (89 patients). The preoperative group was further subdivided into four subgroups according to the time of initiation of therapy: 1–3 days before surgery (group A, 54 patients), 4–6 days before surgery (group B, 57 patients), 7–9 days before surgery (group C, 15 patients), and 10–12 days before surgery (group D, 7 patients). Occurrences of DVT, PE, adverse drug effects, intraoperative and postoperative bleeding were recorded, along with concentrations of preoperative and postoperative hemoglobin and length of hospital stay. The above parameters were compared between groups.

Results

Among recipients of preoperative anticoagulation therapy, two patients developed postoperative PE (1.5 %), one patient developed DVT (0.75 %). In the group receiving postoperative initiation of anticoagulation therapy, one patient each developed PE and DVT (1.1 %, 1.1 %). There was no difference in the occurrence of PE and DVT between the two groups (P>0.05, Chi-square tests). We identified the incidences of major bleeding, minor bleeding, and intraspinal hematoma after spinal anesthesia, which were 0 %/0 %, 3.76 %/3.37 %, and 0 %/0 %, respectively in preoperative and postoperative anticoagulation groups. There was no significant difference in the incidence of bleeding complications between patients receiving preoperatively initiated LMWH with patients receiving postoperatively initiated LMWH. Spinal anesthesia was administered to 168 patients, with no cases of postoperative intraspinal hematoma.

Conclusions

Preoperative anticoagulation therapy with LMWH may not increase intraoperative or postoperative blood loss, or the rate of intraspinal hematoma after spinal anesthesia, but also does not significantly reduce the risk of postoperative DVT or PE, compared to postoperative initiation.

Thromboembolic disease after knee arthroplasty is rare in Southern Iran

BACKGROUND

Thromboembolic disease (TED) after knee arthroplasty occurs infrequently in Iran. The aim of this study was to examine the incidence of TED in patients with osteoarthritis undergoing knee replacement in Southern Iran while on prophylaxis.

MATERIALS & METHODS

In a case series study from January to December 2012, 100 consecutive total knee arthroplasty (TKA) candidates were evaluated for TED by clinical evaluation and Doppler sonography preoperatively and 2 months postoperatively and by clinical evaluation one year after surgery. The patients in this study randomly received either warfarin or enoxaparin prophylactically.

RESULTS

A total of 77 women and 23 men with mean age of 67 years (52-82 years) entered the study. The average hemoglobin drop of 2.7 g with warfarin and 3.3 with enoxaparin was observed. No case of TED, pulmonary embolus (PE), major bleeding, post-thrombotic syndrome, or hemarthrosis was observed.

CONCLUSION

No clinically significant DVT was found using either enoxaparin or warfarin prophylaxis after TKA in Southern Iran. Relatively excessive postoperative bleeding was observed, particularly with enoxaparin.

Thromboembolic and bleeding outcomes of extended duration low-intensity warfarin following elective total knee arthroplasty

INTRODUCTION

The purpose of this study was to describe the incidence of symptomatic venous thromboembolism (VTE), clinically-relevant bleeding, and death among a real-world population receiving warfarin prophylaxis targeting an international normalized ratio (INR) of 1.5 to 2.5 for four weeks following total knee arthroplasty (TKA).

MATERIALS AND METHODS

This retrospective, observational study included patients receiving warfarin following a TKA between August 1, 2005 and July 31, 2009 identified in the Kaiser Permanente Total Joint Replacement Registry. Patients<18 years, receiving warfarin for another indication, or without continuous KPCO membership during the study period were excluded.

RESULTS

There were 1487 patients with TKA included in the analysis. Mean patient age was 67.7 years and 61.7% were female. The median percent of time in therapeutic INR range during follow-up was 55% (interquartile range=35%-75%). Nineteen cases of symptomatic VTE [1.3%; 95% confidence interval (CI) 0.8%-2.0%] including ten pulmonary emboli (PE) (0.7%) were identified within 90 days of surgery. Clinically-relevant bleeding occurred in 1.7% (95% CI 1.1%-2.5%) of patients during warfarin prophylaxis and there were no deaths within 90 days of surgery.

CONCLUSIONS

The rates of symptomatic VTE and clinically-relevant bleeding following TKA in patients receiving warfarin prophylaxis with a target INR of 1.5 to 2.5 were low. Additional studies should include low-intensity warfarin to identify the regimen that optimally balances risks of bleeding and symptomatic VTE after major orthopedic surgery.

Pharmacoeconomic evaluation of dabigatran, rivaroxaban and apixaban versus enoxaparin for the prevention of venous thromboembolism after total hip or knee replacement in Spain

BACKGROUND

Patients undergoing total hip replacement (THR) or total knee replacement (TKR) surgery are at high risk of developing venous thromboembolism (VTE). Thromboprophylaxis with low-molecular-weight heparin, such as enoxaparin, is standard of care in these patients. Recently, three direct oral anticoagulants (DOACs; dabigatran, rivaroxaban and apixaban), have been approved for this indication, but their cost effectiveness is still unclear as it has usually been extrapolated from surrogate venographic outcomes in clinical trials.

OBJECTIVE

To conduct a pharmacoeconomic evaluation of the DOACs versus subcutaneous (SC) enoxaparin for the prevention of VTE after THR or TKR surgery.

METHODS

A decision-tree model was developed using TreeAge Pro 2011 to compare the cost utility and cost effectiveness of the DOACs with SC enoxaparin, with separate models for THR and TKR over a 3-month postoperative time horizon from the perspective of the Spanish National Health System. The probabilities of events (symptomatic VTE, clinically relevant bleedings, heparin-induced thrombocytopenia and deaths) were derived from a systematic review and meta-analysis. We used local cost estimates (€2013) and utility values were obtained from the literature. We reported costs, quality-adjusted life-years (QALYs) and symptomatic VTE events. We conducted sensitivity analyses to evaluate parameter uncertainty.

RESULTS

The average costs per 1,000 patients treated with enoxaparin were higher than costs incurred by dabigatran, rivaroxaban and apixaban in THR (€435,208 vs. €283,574, €257,900 and €212,472, respectively) and TKR (€336,550 vs. €219,856, €251,734 and €201,946, respectively), with cost savings ranging from €151,634 to €222,766 in THR, and from €84,816 to €134,604 in TKR. Cost differences were largely driven by differences in costs associated with drug administration. The average QALYs per 1,000 patients treated were very similar for enoxaparin, dabigatran, rivaroxaban and apixaban in THR (199.34, 198.83, 199.08 and 199.68, respectively) and TKR (198.95, 199.41, 198.75 and 199.97, respectively). Rivaroxaban (in TKR and THR) and apixaban (in THR) avoided additional symptomatic VTE events compared with enoxaparin. Sensitivity analyses generally supported the robustness of the analysis to changes in model parameters.

CONCLUSIONS

Our model suggests, based on its underlying assumptions and data, that the DOACs are cost-saving alternatives to SC enoxaparin for the prevention of VTE after THR or TKR, in the Spanish healthcare setting.

Biomarkers of Coagulation and Fibrinolysis during Cemented Total Hip Arthroplasty with Pre- versus Postoperative Start of Thromboprophylaxis

Venous thrombosis is common in elective hip surgery, and prophylaxis is recommended. Clinical trials suggest that the drug dose and timing of initiating prophylaxis significantly influence antithrombotic effectiveness and safety. We studied the time course and gradient of plasma coagulation and fibrinolysis during total hip arthroplasty (THA) in twenty patients that were randomly assigned to have the first dose of 5000 IU dalteparin subcutaneously (sc) injected 12 hours before or 6 hours after surgery. Baseline characteristics were similar in both groups. Specific biomarkers on coagulation (prothrombin fragment 1+2 (F1+2)) and fibrinolytic activity (plasmin/α2-antiplasmin complex (PAP) and D-dimer) were collected at six events during hospitalization and analysed. There were no significant group differences in the biomarkers at any time point. The highest concentrations were measured 6 hours after surgery and before the first postoperative injection. A marked decrease followed at the first postoperative day, and then a second increase in plasma concentrations was observed 6 days after surgery. This study showed that activation of coagulation and fibrinolysis by the operative trauma was the same when the first dose of dalteparin was injected 12 hours before or 6 hours after surgery.

Comparative safety and efficacy of antithrombotics in the management of venous thromboembolism after knee or hip replacement surgery: focus on rivaroxaban

Routine thromboprophylaxis represents the current standard of care in the management of patients following total hip or knee replacement. Legacy agents used to address the issue of risk of venous thromboembolism present barriers to use, either by the need for monitoring and dose adjustment (warfarin) or the need for injection (low molecular weight heparins and fondaparinux), or pose a risk of upper gastrointestinal bleeding (acetylsalicylic acid and all antithrombotic agents). The introduction of new pharmacologic agents in recent years has sought to address the issues of not only efficacy, but also safety, ease of use, and patient compliance. New orally administered agents, ie, apixaban, dabigatran, and rivaroxaban, have demonstrated various degrees of efficacy over enoxaparin while preserving safety. Indirect comparisons of the relative efficacies of apixaban, dabigatran, and rivaroxaban have shown rivaroxaban to be more efficacious than dabigatran and apixaban in reducing symptomatic and total venous thromboembolism following total hip or knee replacement surgery. A pooled analysis of the four RECORD (Regulation of Coagulation in Orthopedic Surgery to Prevent deep vein thrombosis and pulmonary embolism) trials (two in total hip replacement and two in total knee replacement) demonstrated rivaroxaban to be the first and only antithrombotic agent ever to demonstrate superiority in reducing symptomatic venous thromboembolism and all-cause mortality compared with another antithrombotic agent (enoxaparin). New oral antithrombotic agents have demonstrated efficacy in prophylaxis against venous thromboembolism following total hip or knee replacement surgery while preserving safety, with increased ease of administration of thromboprophylaxis for both the patient and the physician, which may contribute to improved compliance.

Novel oral anticoagulants for thromboprophylaxis after orthopaedic surgery

The direct thrombin inhibitor, dabigatran, and the selective factor Xa inhibitors, rivaroxaban and apixaban, are new oral anticoagulants that are approved in many countries for prevention of venous thromboembolism in patients undergoing elective hip or knee arthroplasty. All have a rapid onset of action, a low potential for food and drug interactions and a predictable anticoagulant effect that obviates the need for routine coagulation monitoring. These agents offer a convenient alternative to conventional anticoagulant drug regimens, including parenteral low-molecular-weight heparins and fondaparinux, and oral adjusted-dose vitamin K antagonists, for the prevention of venous thromboembolism in this surgical setting. This review summarizes the pharmacology, clinical trial results, bleeding risk and practical use of these new oral anticoagulants in clinical orthopaedic practice. Potential issues to be considered when using these oral anticoagulants include renal impairment, potential drug interactions, neuraxial anaesthesia and management of bleeding.

NEW ANTICOAGULANTS AS THROMBOPROPHYLAXIS AFTER TOTAL HIP OR KNEE REPLACEMENT

Objectives: Due to a high risk of thromboembolism in patients undergoing major orthopedic surgery, it has become standard practice to give thromboprophylactic treatment. We assessed the relative efficacy and cost-effectiveness of two new oral anticoagulants, rivaroxaban and dabigatran, relative to subcutaneous enoxaparin for the prevention of thromboembolism after total hip replacement (THR) and total knee replacement surgery (TKR).

Methods: We conducted a systematic review of the literature to assess efficacy and safety, and evaluated quality of documentation using GRADE. Cost-effectiveness was assessed by developing a decision model. The model combined two modules; a decision tree for the short-term prophylaxis and a Markov model for the long-term complications and survival gain.

Results: For rivaroxaban compared with enoxaparin, we found statistically significant decreases in deep vein thrombosis, but also a trend toward increased risk of major bleeding. For mortality and pulmonary embolism there were no statistically significant differences between the treatments. We did not find statistically significant differences between dabigatran and enoxaparin for our efficacy and safety outcomes. Assuming a willingness to pay of EUR62,500 per QALY, rivaroxaban following THR had a probability of 38 percent, and enoxaparin following TKR had a probability of 34 percent of being cost-effective. Clinical efficacy had the greatest impact on decision uncertainty.

Conclusions: Dabigatran and rivaroxaban are comparable with enoxaparin following THR and TKR regarding the efficacy and safety outcomes. However, there is great uncertainty regarding which strategy is the most cost-effective. More research on clinical efficacy of rivaroxaban and dabigatran is likely to change our results.

[Dabigatran etexilate use among older adults in a home-care system after hip or knee replacement surgery]

INTRODUCTION

Hip replacement surgery (HRS) and knee replacement surgery (KRS) require long-term deep venous thrombosis (DVT) prophylaxis. This study describes dabigatran etexilate (DE) use in post-surgical older adults who underwent HRS and KRS in a clinical practice setting in a home-care system.

MATERIAL AND METHODS

A retrospective descriptive cohort study included elective HRS and KRS postsurgical older adults under home care receiving either DE (n=76) or enoxaparin (n=80). DE was indicated by using the same selection criteria and dosing as in the RE-MODEL and RE-NOVATE studies. The enoxaparin 40 mg/day patients were included as historic controls when they met the same selection criteria as DE patients. Symptomatic DVT, bleeding rate, re-admission rate and mortality during the 90-day postsurgical period were analyzed.

RESULTS

The mean age of the DE group was 74 (5) years old, with 74% females. There were no significant differences in age, gender and type of replacement between the two groups. There were four DVT in each group (50% proximal), with no significant differences found between groups. There was one pulmonary thromboembolism in the DE group, and one major bleeding in the enoxaparin group. There were no deaths during the 90-day follow-up; however, two re-hospitalizations occurred in the DE group. The details on introducing DE use in our home-care system are also described.

CONCLUSIONS

In appropriately selected older adults DE seems to be an effective choice for DVT prophylaxis in home-care in a clinical practice setting.

Recombinant factor VIIa treatment for asymptomatic factor VII deficient patients going through major surgery

Factor VII deficiency is the most common among the rare autosomal recessive coagulation disorders worldwide. In factor VII deficient patients, the severity and clinical manifestations cannot be reliably determined by factor VII levels. Severe bleeding tends to occur in individuals with factor VII activity levels of 2% or less of normal. Patients with 2-10% factor VII vary between asymptomatic to severe life threatening haemorrhages behaviour. Recombinant factor VIIa (rFVIIa) is the most common replacement therapy for congenital factor VII deficiency. However, unlike haemophilia patients for whom treatment protocols are straight forward, in asymptomatic factor VII deficiency patients it is still debatable. In this study, we demonstrate that a single and very low dose of recombinant factor VIIa enabled asymptomatic patients with factor VII deficiency to go through major surgery safely. This suggestion was also supported by thrombin generation, as well as by thromboelastometry.

Clinical trials with new oral anticoagulants. Additive value of indirect comparisons also named network meta-analyses

To compare the efficacy and safety of the new oral anticoagulants (NOAC), ideally head-to-head clinical trials should be performed. Given the expense of such an undertaking, it is highly unlikely that such a comparison would be performed. Therefore, there is a need for an unbiased comparative assessment of the benefits and risks of the NOACs, based on the available trial data. Indirect or mixed treatment comparisons may be an useful tool to overcome these limitations also known as network meta-analysis (NMA). The aim of this paper is to give an overview on published NMAs for dabigatran, rivaroxaban and apixaban, each assessed against warfarin in patients with atrial fibrillation, and against enoxaparin in patients undergoing total knee and total hip replacement surgery, in order to obtain insights into the comparability of the adopted methodological techniques.

Systematic review of randomized controlled trials of new anticoagulants for venous thromboembolism prophylaxis in major orthopedic surgeries, compared with enoxaparin

BACKGROUND

In the past 10 years, new anticoagulants (NACs) have been studied for venous thromboembolism (VTE) prophylaxis.

OBJECTIVE

To evaluate the risk/benefit profile of NACs versus enoxaparin for VTE prophylaxis in major orthopedic surgery.

METHODS

A systematic review of double-blind randomized phase III studies was performed. The search strategy was run from 2000 to 2011 in the main medical electronic databases in any language. Independent extraction of articles was performed by 2 authors using predefined data fields, including study quality indicators.

RESULTS

Fifteen published clinical trials evaluating fondaparinux, rivaroxaban, dabigatran, and apixaban were included. Primary efficacy (any deep vein thrombosis [DVT], nonfatal pulmonary embolism, or all-cause mortality) favored fondaparinux (relative risk [RR] 0.50; 95% CI, 0.39, 0.63) and rivaroxaban (RR, 0.50; 95% CI, 0.34, 0.73) over enoxaparin, although significant heterogeneity was observed in both series. The primary efficacy of dabigatran at 220 mg, apixaban, and bemiparin were similar, with RRs of 1.02 (95% CI, 0.86, 1.20), 0.63 (95% CI, 0.39, 1.01), and 0.87 (95% CI, 0.65, 1.17), respectively. The primary efficacy of dabigatran at 150 mg (RR, 1.20; 95% CI, 1.03, 1.41), was inferior to enoxaparin. The incidence of proximal DVT favored apixaban (RR, 0.45; 95% CI, 0.27, 0.75) only. Rivaroxaban (RR, 0.45; 95% CI, 0.27, 0,77) and apixaban (RR, 0.38; 95% CI, 0.16, 0.90) produced significantly lower frequencies of symptomatic DVT. The incidence of major VTE favored rivaroxaban (RR, 0.44; 95% CI, 0.25, 0.81), only. Bleeding risk was similar for all NACs, except fondaparinux (RR, 1.27; 95% CI, 1.04, 1.55), which exhibited a significantly higher any-bleeding risk compared with enoxaparin, and apixaban (RR, 0.88; 95% CI, 0.79, 0.99), which was associated with a reduced risk of any bleeding. Alanine amino transferase was significantly lower with 220 mg of dabigatran, (RR, 0.67; 95% CI, 0.79, 0.99) than with enoxaparin.

CONCLUSIONS

NACs can be considered alternatives to conventional thromboprophylaxis regimens in patients undergoing elective major orthopedic surgery, depending on clinical characteristics and cost-effectiveness. The knowledge of some differences concerning efficacy or safety profile, pointed out in this systematic review, along with the respective limitations, may be useful in clinical practice.