BACKGROUND: The purpose of this study is to perform a meta-analysis to compare outcomes of venous thromboembolism (VTE) prophylaxis with low-molecular-weight heparin (LMWH) vs other anticoagulants in patients who received total knee (TKA) or total hip arthroplasty (THA).
METHODS: MEDLINE, Cochrane, EMBASE, and Google Scholar databases were searched until June 30, 2017 for eligible randomized controlled studies.
RESULTS: Thirty-two randomized controlled studies were included. LMWH provided better protection against VTE than placebo. In both TKA and THA patients, the rates of VTE were lower with factor Xa inhibitors than LMWH. In THA patients, the rate of deep vein thrombosis (DVT) was lower with factor Xa inhibitors than LMWH. In TKA patients, the rates of VTE and DVT were similar between LMWH and direct thrombin inhibitors. In THA patients, the rate of VTE was lower with direct thrombin inhibitors than with LMWH, while the DVT rates were similar. The pulmonary embolism rates were similar between all 3 classes of drugs in TKA and THR patients, as were the major bleeding rates. Nonmajor and minor bleeding rates were also similar between the 3 drug classes.
CONCLUSION: LMWH is associated with a higher rate of VTE than factor Xa inhibitors in TKA and THA patients. Direct thrombin inhibitors are associated with a lower rate of VTE in THA patients, but their effectiveness with respect to DVT and pulmonary embolism prophylaxis is similar to that of LMWH in TKA and THA patients.
BACKGROUND: Patients undergoing total hip arthroplasty (THA) or total knee arthroplasty (TKA) are at risk of venous thromboembolism (VTE). Australian orthopaedic guidelines recommend aspirin and low-molecular-weight heparin (e.g. enoxaparin) for VTE prophylaxis; however, there is debate in the international literature around the use of aspirin as VTE prophylaxis. This review assesses the risks and benefits of aspirin compared to enoxaparin as VTE prophylaxis for patients undergoing THA or TKA.
METHODS: A systematic review was conducted to identify relevant randomized controlled trials. Studies comparing enoxaparin, aspirin and/or placebo for VTE prophylaxis in THA or TKA patients were included. Network meta-analysis (NMA) was performed to calculate risk ratios (RRs) and confidence intervals (CIs). Quality appraisal was conducted by assessing risk of bias and the strength of the evidence.
RESULTS: Nine randomized controlled trials were eligible for inclusion. The NMA found no statistically significant differences for the investigated outcomes: total DVT rates (RR = 1.21, 95% CI 0.86, 1.72), symptomatic pulmonary embolism (PE) rates (RR = 1.02, 95% CI 0.02, 50.86), major haemorrhage (RR = 0.97, 95% CI 0.02, 50.99) and wound complication (RR = 0.73, 95% CI 0.17, 3.20). The occurrence of PE was rare. Due to limited data, sub-group analysis was not possible. The overall quality of evidence in the NMA is considered to be very low.
CONCLUSION: This review did not find statistically significant differences between aspirin and enoxaparin. Future studies should identify more evidence, particularly for rare outcomes such as PE, as this might help decision-makers to get consensus on the use of aspirin as VTE prophylaxis.
BACKGROUND: Currently there is significant variation in the management of venous thromboembolism prophylaxis following total knee arthroplasty (TKA). Excessive wound ooze and bleeding is thought to increase a patient's risk of haematoma formation and possible infection. We evaluated the rate of unexpected reoperation in the perioperative period in patients who received aspirin, rivaroxaban or enoxaparin following primary TKA.
METHOD: A systematic literature search was conducted in MEDLINE, CENTRAL and Embase to identify patients who underwent primary TKA. Two researchers independently reviewed the references identified in the literature search. The final 11 studies included for review were published between 1996 and 2016.
RESULTS: There was a higher rate of reoperation in patients treated with aspirin following TKA when compared to enoxaparin and rivaroxaban in the perioperative period. Of the 5141 patients treated with enoxaparin, 11 (0.21%) required reoperation; of the 2764 patients treated with rivaroxaban, 12 (0.43%) required reoperation; and of the 228 patients treated with aspirin, seven (3.07%) required reoperation. The average time to follow-up in the 11 studies was 55 days, ranging from 30 to 180 days post-operatively.
CONCLUSION: There was a higher rate of reoperation in patients treated with aspirin following TKA when compared to enoxaparin and rivaroxaban in the perioperative period. While there is extensive data on the safety and efficacy of these medications following joint arthroplasty, improved reporting of surgically relevant outcomes are needed to assist both the surgeon and patient in clinical decision-making.
Background: Patients who undergo knee or hip arthroplasty are at a significant risk of venous thromboembolism (VTE) development (pulmonary embolism and/or deep-vein thrombosis). Many different thromboprophylactic strategies have been used for the prevention of VTE in these patients with different outcomes. Therefore, our aim was to evaluate the efficacy and safety of aspirin prophylaxis when compared with placebo or anticoagulants in this population of patients. Methods: A comprehensive electronic database search was conducted for all randomized controlled trials (RCTs) comparing the clinical outcomes of aspirin versus placebo or anticoagulants for the prevention of VTE after knee or hip arthroplasty. The primary outcome was VTE incidence. Secondary outcomes included any bleeding, major bleeding and mortality. We calculated risk ratios (RRs) and 95% confidence intervals (CIs) using a random-effects model at the longest possible follow-up period. Results: We included 13 RCTs with a total of 20,115 patients with a mean age of 67.15 ± 9.54 and 24.39% males. Aspirin was found to be associated with a non-significantly reduced VTE events compared with other thromboprophylactic methods (RR 0.87; 95% CI: 0.61–1.23; P = 0.43). Compared with placebo, aspirin was associated with significant reduction of VTE (RR 0.65; 95% CI: 0.47–0.89; P = 0.008). There were no significant differences in the clinical outcomes between all groups with regard to mortality (RR 0.98; 95% CI: 0.86–1.11; P = 0.72), major bleeding events (RR 0.96; 95% CI: 0.50–1.84; P = 0.91), and any bleeding events (RR: 1.09; 95% CI: 0.82–1.44; P = 0.56). Conclusion: Among patients who underwent knee or hip arthroplasty, aspirin prophylaxis was found to be associated with similar efficacy and safety outcomes when compared with anticoagulants. When compared with placebo, aspirin prophylaxis was associated with significantly reduced VTE and a comparable safety profile.
ESSENTIALS: Despite trial data, guidelines have not endorsed direct oral Xa inhibitors above other options. We provide profiles of venous thromboembolism and hemorrhage risk for 12 options. Direct oral Xa inhibitors had a favorable profile compared with low-molecular-weight heparin. Other options did not have favorable profiles compared with low-molecular-weight heparin.
SUMMARY:
BACKGROUND: There are numerous trials and several meta-analyses comparing venous thromboembolism (VTE) prophylaxis options after total hip and knee replacement (THR and TKR). None have included simultaneous comparison of new with older options. Objective To measure simultaneously the relative risk of VTE and hemorrhage for 12 prophylaxis options. METHODS: We abstracted VTE and hemorrhage information from randomized controlled trials published between January 1990 and June 2016 comparing 12 prophylaxis options. We then constructed networks to compute the relative risk for each option, relative to once-daily dosing with low-molecular-weight heparin (LMWH) Low. RESULTS MAIN: Relative to LMWH Low, direct oral Xa inhibitors had the lowest risk of total deep vein thrombosis (DVT)-asymptomatic and symptomatic- (odds ratio [OR], 0.45; 95% confidence interval [CI], 0.35-0.57), translating to 53-139 fewer DVTs per 1000 patients. Vitamin K antagonists (VKAs) titrated to International Normalized Ratio [INR] 2-3 predicted 56% more DVT events (OR, 1.56; 95% CI, 1.14-2.14). Aspirin performed similarly (OR, 0.80; 95% CI, 0.34-1.86), although small numbers prohibit firm conclusions. Direct oral Xa inhibitors did not lead to significantly more bleeding (OR, 1.21; 95% CI, 0.79-1.90). Secondary: Relative to LMWH Low, direct oral Xa inhibitors prevented 4-fold more symptomatic DVTs (OR, 0.25; 95% CI, 0.13-0.47). CONCLUSIONS: Relative to LMWH Low, direct oral Xa inhibitors had a more favorable profile of VTE and hemorrhage risk, whereas VKAs had a less favorable profile. The profile of other agents was not more or less favorable. Clinicians should consider these profiles when selecting prophylaxis options.
BACKGROUND: Venous thromboembolism causes significant morbidity and mortality in patients after total joint arthroplasty. Although network meta-analyses have demonstrated a benefit of various thromboprophylactic agents, there remains a concern in the surgical community regarding the resulting wound complications. There is currently no systematic review of the surgical site bleeding complications of thromboprophylactic agents. The aim of this study was to systematically review the surgical site bleeding outcomes of venous thromboembolism prophylaxis in this population.
METHODS: A systematic review and meta-analysis was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Randomized controlled trials comparing more than one of low-molecular-weight heparin (LMWH), warfarin, rivaroxaban, apixaban, dabigatran, aspirin, or no pharmacologic treatment in patients after total hip or knee arthroplasty were selected for inclusion. Five meta-analyses were performed to compare LMWH with control, warfarin, apixaban, rivaroxaban, and dabigatran.
RESULTS: Forty-five randomized controlled trials of 56,730 patients were included. LMWH had a significantly increased relative risk of surgical site bleeding in comparison with control (relative risk, 2.32; 95% confidence interval, 1.40-3.85) and warfarin (1.54; 1.23-1.94). The relative risk of LMWH trended higher than apixaban (1.27; 1.00-1.63) and was similar to rivaroxaban (0.95; 0.74-1.23). Only 1 study reported the risk of surgical site bleeding in LMWH vs dabigatran (5.97; 2.08-17.11).
CONCLUSION: LMWH increased the risk of surgical site bleeding compared with control, warfarin. and dabigatran and trended toward an increased risk compared with apixaban. The risk of surgical site bleeding was similar with LMWH and rivaroxaban.
BACKGROUND: Major orthopedic surgeries, such as total knee replacement (TKR), total hip replacement (THR), and hip fracture (HFx) surgery, carry a high risk for venous thromboembolism (VTE)—deep vein thrombosis (DVT) and pulmonary embolism (PE).
METHODS: Updating a 2012 review, we compare interventions to prevent VTE after TKR, THR, and HFx surgery. We searched four databases and other sources through June 3, 2016, for randomized controlled trials (RCTs) and large nonrandomized comparative studies (NRCSs) reporting postoperative VTE, major bleeding, and other adverse events. We conducted pairwise meta-analyses, Bayesian network meta-analyses, and strength of evidence (SoE) synthesis.
RESULTS: Overall, 127 RCTs and 15 NRCSs met criteria. For THR: low molecular weight heparin (LMWH) has lower risk than unfractionated heparin (UFH) of various VTE outcomes (moderate to high SoE) and major bleeding (moderate SoE). LMWH and aspirin have similar risks of total PE, symptomatic DVT, and major bleeding (low SoE). LMWH has less major bleeding (low SoE) than direct thrombin inhibitors (DTI), but DTI has lower DVT risks (moderate SoE). LMWH has less major bleeding than vitamin K antagonists (VKA) (high SoE). LMWH and factor Xa inhibitor (FXaI) comparisons are inconsistent across VTE outcomes, but LMWH has less major bleeding (high SoE). VKA has lower proximal DVT risk than mechanical devices (high SoE). Longer duration LMWH has lower risk of various VTE outcome risks (low to high SoE). Higher dose LMWH has lower total DVT risk (low SoE) but more major bleeding (moderate SoE). Higher dose FXaI has lower total VTE risk (low SoE). For TKR: LMWH has lower DVT risks than VKA (low to high SoE), but VKA has less major bleeding (low SoE). FXaI has lower risk than LMWH of various VTE outcomes (low to moderate SoE), but LMWH has less major bleeding (low SoE) and more study-defined serious adverse events (low SoE). Higher dose DTI has lower DVT risk (moderate to high SoE) but more major bleeding (low SoE). Higher dose FXaI has lower risk of various VTE outcomes (low to moderate SoE). For HFx surgery: LMWH has lower total DVT risk than FXaI (moderate SoE).
CONCLUSIONS: VTE prophylaxis after major orthopedic surgery trades off lowered VTE risk with possible adverse events—in particular, for most interventions, major bleeding. In THR, LMWH has lower VTE and adverse event risks than UFH, LMWH and aspirin have similar risks of VTE and major bleeding, DTI has lower DVT risk than LMWH but higher major bleeding risk, and higher dose LMWH has lower DVT risk but higher major bleeding risk than lower dose. In TKR, VKA has higher DVT risk than LMWH but lower major bleeding risk, and higher dose DTI has lower DVT risk but higher major bleeding risk than lower dose. In HFx surgery and for other intervention comparisons, there is insufficient evidence to assess both benefits and harms, or findings are inconsistent. Importantly, though, most studies evaluate “total DVT” (an outcome of unclear clinical significance since it includes asymptomatic and other low-risk DVTs), but relatively few studies evaluate PE and other clinically important outcomes. This limitation yields a high likelihood of selective outcome reporting bias. There is also relatively sparse evidence on interventions other than LMWH.
BACKGROUND: A symptomatic pulmonary embolism (PE) after total joint arthroplasty has been described as a "never event." Despite potent anticoagulants and improvements in patient care, PE continues to occur following total hip arthroplasty (THA). This study evaluates symptomatic PE rates over time in THA patients enrolled in multicenter randomized clinical trials (RCTs) assessing the efficacy of venous thromboembolism prophylaxis regimens.
METHODS: The MEDLINE and Cochrane Central Register of Controlled Trials were searched to identify clinical trials assessing prophylactic anticoagulation in patients undergoing THA between January 1995 and December 2015. Inclusion criteria consisted of RCTs evaluating prophylactic anticoagulation in patients undergoing THA. A random effect model was used to combine PE rates across studies.
RESULTS: A total of 21 studies (34,764 patients) were included. Patients were administered low molecular weight heparin (13,590 patients), oral factor Xa inhibitors (6609 patients), oral direct thrombin inhibitors (5965 patients), indirect factors Xa/IIa inhibitors (3444 patients), aspirin (2427 patients), and warfarin (489 patients). Mobile compression was used in 199 patients, and placebo was used in 2041 patients. Across all included studies, the estimated PE rate was 0.21% (95% confidence interval: 0.13%, 0.32%). Between 1997 and 2013, the proportion of PEs did not change in regression analysis.
CONCLUSION: Although the PE rate was low, it was consistent throughout the 17 years spanning these RCTs, which excluded patients with significant morbidity. These results suggest that even healthy THA patients receiving aggressive anticoagulation still have a risk for PE, and the "never event" designation requires reassessment.
INTRODUCTION: Currently there are no consensuses in the national guidance on thromboprophylaxis following major elective lower limb surgery. Emerging clinical evidence suggests that aspirin could be just as effective as anticoagulants with a lower cost. The aim of this study was to provide an update based on literature of the past 3 years for the use of aspirin as thromboprophylaxis after knee and hip arthroplasty. MATERIALS AND METHODS: MEDLINE/EMBASE search was performed with appropriate terms for original articles from 2014 to 2017. RESULTS: Eight articles were found. Five articles concluded that aspirin was an effective prophylactic. The collation of results on the deep vein thrombosis rate involved 43,012 patients who were prescribed aspirin, of which 283 (0.66%) suffered from symptomatic deep vein thromboses. Aspirin was noted for its good side effect profile and cost effectiveness. It was noted that anticoagulants had a higher rate of complications, including bleeding and wound-oozing. CONCLUSION: Aspirin is an effective and safe prophylactic against deep vein thrombosis following major elective lower limb arthroplasty surgery.
