Thromboprophylaxis With Apixaban in Patients Undergoing Major Orthopedic Surgery: Meta-Analysis and Trial-Sequential Analysis

Current Evidence and Expert Opinion on Thromboprophylaxis After Total Knee and Hip Replacement

An effective anticoagulant provides a balance between the risk for venous thromboembolism (VTE) and bleeding and is crucial in achieving optimal clinical outcomes in patients undergoing total hip replacement (THR) and total knee replacement (TKR) surgeries. We performed a review of the literature on thromboprophylaxis for patients undergoing total hip or knee replacement. This review article summarizes current guidelines and evidence for anticoagulation along with the expert opinion about pharmacological VTE prophylaxis, particularly non-Vitamin K antagonist oral anticoagulants (NOACs), for patients after total hip or knee replacement. Aspirin for VTE prophylaxis after TKR/THR has been controversial and most of the evidence is reported from observational research. Although the guidelines do not recommend any specific thromboprophylaxis agent, available evidence suggests that NOACs are as effective as low molecular weight heparins (LMWHs) in preventing VTE. Oral administration and the lack of dose monitoring make NOACs easy to use in outpatient settings in cases with challenging treatment compliances. They can be used for two weeks after TKR and five weeks after THR - six weeks after TKR and THR to cover the at-risk period for VTE post-discharge. Owing to the lack of evidence for a head-to-head comparison of NOACs, an anticoagulant with better efficacy and safety may be suggested in special patient populations (elderly, obese patients, or those with renal dysfunction). The expert opinion on pharmacological VTE prophylaxis provided in this article could address some gaps in the management of anticoagulation in patients with total hip or knee replacement.

Role of Direct Oral Anticoagulants for Post-operative Venous Thromboembolism Prophylaxis

Venous thromboembolism (VTE) is one of the leading causes of post-operative morbidity and mortality. Over previous decades, heparin and warfarin were the predominant therapeutic options for post-operative thromboprophylaxis. However, their use is limited by drawbacks including a narrow therapeutic range, numerous food and drug interactions, and the need for regular monitoring for dose adjustments. Recently, direct oral anticoagulants (DOACs), such as dabigatran etexilate (a direct thrombin inhibitor) and apixaban, rivaroxaban and edoxaban (direct factor Xa inhibitors), have been developed to overcome these issues. DOACs have shown promising results in Phase III clinical trials for post-operative VTE prophylaxis. This review summarises the pharmacological profile of DOACs and highlights the use of DOACs in post-operative VTE prophylaxis based on the available clinical trial data.

Combined intravenous and intra-articular tranexamic acid administration in total knee arthroplasty for preventing blood loss and hyperfibrinolysis: A randomized controlled trial

BACKGROUND

Total knee arthroplasty (TKA) is a surgical procedure to replace the weight-bearing surfaces of the knee joint to relieve pain and disability. However, blood loss and fibrinolytic activity, accounting for a poor prognosis following TKA operation, were relieved by fibrinolytic inhibitor tranexamic acid (TXA). For a better application of TXA function, we explored the effect of intravenous injection (IV) of TXA combined with intra-articular injection (IA) of TXA in patients after TKA.

METHODS

Patients admitted from Weifang People's Hospital from January 2015 to December 2016 who received TKA were injected with 20 mg/kg TXA by IV before TKA (n = 50), 3.0 g TXA by IA after TKA (n = 50), or combination of 20 mg/kg TXA by IV before TKA and 3.0 g TXA by IA after TKA (n = 50). Knee function was assessed using HSS, KSS, NASS, and ROM. In addition, the total blood loss (TBL), hidden blood loss (HBL), maximum hemoglobin (Hb) drop, fibrinolytic activity, as well as incidence of thromboembolism were measured. The patients were followed up for 6 months. The deadline for follow-up was June 2017 and the incidence of thromboembolism events within 6 months after operation was counted.

RESULTS

HSS, KSS, NASS scores, and ROM were elevated after patients receiving TKA. Patients received IV plus IA TXA has decreased TBL, HBL, and maximum Hb drop than those received IV TXA-alone and IA TXA-alone, with reductions in FDP and D-dimer, indicating that IV plus IA TXA injection is superior to prevent blood loss and hyperfibrinolysis during TKA. Age, sex, type of femoral prosthesis, and the injection method of TXA were risk factors for HBL of patients after receiving TKA.

CONCLUSIONS

The aforementioned results demonstrate that TKA is an effective surgery, and IV plus IA TXA injection functions more effectively in reducing blood loss and fibrinolytic activity in patients, which is a clinical factor of occult hemorrhage.

Non-vitamin K antagonist oral anticoagulants in elderly patients with atrial fibrillation: A systematic review with meta-analysis and trial sequential analysis

BACKGROUND

Elderly population is known to be associated with polymedication, comorbidities and altered drug pharmacokinetics. However, the most adequate oral anticoagulant, attending to its relative efficacy and safety, remains unclear.

METHODS

We searched for phase III randomized controlled trials (MEDLINE, Cochrane Library, SciELO collection and Web of Science) comparing novel non-vitamin K antagonist oral anticoagulants (NOACs) with Vitamin K antagonists (VKA) in the elderly population (≥75 years-old) in atrial fibrillation (AF). Risk ratios (RR) were calculated using a random effects model. Trial sequential analysis (TSA) was performed in statistically significant results to evaluate whether cumulative sample size was powered.

RESULTS

Four trials rendered data about elderly (≥75 years-old) and younger patients (<75 years-old) with AF. NOACs demonstrated a 30% significant risk reduction (RR 0.70, 95% CI: 0.61 to 0.80) in elderly patients compared to VKA, without heterogeneity across studies (I² = 0%). The TSA showed that cumulative evidence of this subgroup exceeded the minimum information size required for the risk reduction. In younger patients, VKA and NOACs shared a similar risk of stroke and systemic embolism (RR 0.97, 95% CI: 0.79 to 1.18). Regarding major bleeding risk in the elderly, the overall comparative risk of NOACs was not different from VKA (RR 0.91, 95% CI: 0.72 to 1.16; I² = 86%).

CONCLUSIONS

NOACs reduce significantly the risk of stroke and systemic embolism in elderly patients without increasing major bleeding events. The dimension of stroke risk reduction was significantly higher in the elderly than in younger adults.

Semiautomatic intermittent pneumatic compression device applied to deep vein thrombosis in major orthopedic surgery

Objective

To investigate the effect of additional semiautomatic intermittent pneumatic compression device (IPCD) in the prevention of deep vein thrombosis (DVT) of lower extremity in these patients undergoing major orthopedic surgery, when compared with the conventional graduated compression stockings alone.

Methods

The data of 112 patients undergoing major orthopedic surgery were retrospectively analyzed. 51 patients who ever received IPCD and graduated compression stockings during major orthopedic surgery were taken as the experimental group, and 61 patients who only received the conventional graduated compression stockings during surgery were taken as the observation group. The Doppler sonography was utilized to detect the presence of DVT and pulmonary embolism pre- and postoperatively. Besides, the mean and peak velocity of blood flow in femoral vein were recorded before and after surgery. And then, the comparisons between the two groups were made, respectively.

Results

When compared with the conventional graduated compression stockings alone, the intraoperative application of IPCD and stockings contributed the significant reduction of DVT (3.92%, 2/51 versus 9.84%, 6/61, X² = 5.632, P = 0.034). In terms of the mean and peak velocity of blood flow in femoral vein, the postoperative difference was higher in the observation group than those in the control group (149.56 ± 26.35 versus 130.15 ± 22.56 mm/s, P < 0.05). With respect to perioperative blood loss, the difference between the two groups was statistically significant (800.5 ± 320.7 versus 950.1 ± 305.9 ml, P = 0.031).

Conclusions

Intraoperative application of IPCD could promote blood circulation of lower limbs, and significantly decrease the incidence of potentially fatal DVT in patients undergoing major orthopedic surgery, when compared with the conventional graduated compression stockings.

Comparison of apixaban and rivaroxaban for anticoagulant effect after lumbar spine surgery: a single-center report

Aim

To compare efficacy and safety of anticoagulants apixaban and rivaroxaban after lumbar spine surgery retrospectively.

Methods

In this study comprising 480 patients, lower-limb swelling, deep venous thrombosis, pulmonary embolism, blood loss, ecchymosis and D-dimer changes were observed.

Results

The changes in perimeter of the legs were tested, and significant differences were noted 10 cm above the patella, but no significant differences 10 cm below the patella. Twelve thrombotic events occurred in the apixaban group and nine in rivaroxaban group. No significant difference in the incidences of thromboembolic events (p = 1.00). Compared with rivaroxaban, there was significantly less bleeding in the apixaban group (p = 0.03).

Conclusion

Apixaban and rivaroxaban were equally effective anticoagulation therapies that exhibited similar preventive effects against postoperative venous thromboembolism after lumbar spine surgery.