Synthesis Apixaban vs Enoxaparin

Hip replacement surgery puts its recipients at risk of deep venous thrombosis (DVT) or venous thromboembolism (VTE), whose complications include, but they are not limited to pulmonary embolism. With thousands of Americans opting for hip replacement every year, and statistics indicating that a significant percentage of patients develop thromboembolism after surgery, there is need to formulate and adopt an effective preventive plan to minimize the risk of DVT or VTE after hip replacement surgery. This assertion is supported by Pannucci, Dreszer, Wachtman, Bailey, Portschy, Hamill and Pusic (2011) who in their research point out that the relevance of studies on the prevention of Venous Thromboembolism cannot be overstated, especially given that VTE is today regarded an important post-operation patient safety concern. Two of the most commonly used options in venous thromboembolism prevention are apixaban and enoxaparin. In that regard, therefore, a review of how effective the two VTE and DVT mitigating mechanisms are and how each compares to the other is not only relevant, but also necessary. Apixaban works by inhibiting thrombi development (as a result of the formation of thrombin) via the inhibition of active factor Xa. In essence, therefore, it is an anticoagulant. Treatment duration using apixaban is often dependent on the kind orthopedic surgery – which determines a patient’s risk for venous thromboembolism. A kind of heparin, enoxaparin, is also an anticoagulant that helps in the activation of antithrombin III – thus effectively bringing about active factor Xa inhibition. Most studies cited herein made use of large samples. For generalization purposes, larger sample sizes in studies of this kind are largely representative, and hence aid validity
In a study seeking to compare enoxaparin to apixaban on the effectiveness front, Lessen, Gallus, Raskob, Pineo, Chen, and Ramirez (2010) found out that the later was more effective in VTE treatment than the former. Albeit for knee replacement surgery, Lassen, Raskob, Gallus, Pineo, Chen, and Hornick (2010) also point out that apixaban also has a wide efficacy rate in comparison to enoxaparin. In essence, knee replacement surgery has also been associated with the prevalence of deep vein thrombosis. This effectively means that some parallels can be drawn between knee replacement surgery and hip replacement surgery. Lassen et al. (2010) point out that in comparison to enoxaparin, apixaban has a high rate of safety and efficiency in the prevention of venous thromboembolism after a patient undergoes knee replacement surgery. This is further collaborated by the findings of a research undertaking by Nieto, Espada, Merino, and Gonzalez (2012) who set about to determine how effective oral anticoagulants were in the treatment of VTE after either hip or knee replacement. It is important to note that the findings of this study also link to findings from Lassen et al. (2010) due to the inclusion of knee replacement as a variable in the study, alongside hip replacement. The oral anticoagulants taken into consideration in this case were inclusive of apixaban. The authors found out that indeed, enoxaparin was less effective than apixaban in the treatment of VTE following either knee or hip surgery. However, unlike Lassen et al., (2010), Nieto, Espada, Merino, and Gonzalez (2012) gave the two interventions a similar safety score. In their study, Lassen et al. (2010) had found apixaban to be safer. On this basis it should be noted that no specific safety concern has been noted with regard to apixaban from previous clinical and nonclinical programs (Trkulja 2016). Findings by Nieto, Espada, Merino, and Gonzalez (2012) seem more applicable given the significant sample size used – in which case the authors recruited a total of 32,144 patients for the research undertaking. Further, unlike is the case in Lassen et al. (2010), the participants were in this case drawn from various countries from across the world. This is of great relevance when it comes to the generalizability of findings.
Like Lessen et al. (2010) Li, Sun, and Zhang (2012) rate apixaban as a more superior drug, in comparison to enoxaparin in the minimization of VTE occurrence post hip or knee surgery. However, unlike Lessen, most of the conclusions Li, Sun, and Zhang (2012) arrived at are on the basis of a review of available data on the issue. The mere assessment of previous studies could be viewed as a limitation of sorts as this does not in any way make meaningful additions to the existing body of research on this particular topic. Others who have found apixaban to be more effective in VTE prevention include Raskob, Gallus, Pineo, Chen, Ramirez, Wright, and Lessen. In their study, titled Apixaban versus enoxaparin for thromboprophylaxis after hip or knee replacement, Raskob et al. (2012) came to a similar conclusion to that of many others listed herein. They found that approximately 0.7 percent of apixaban patients suffered VTE, in comparison to approximately 1.5 of enoxaparin patients. Following similar conclusions from Yan, Gu, Zhou, Lin, and Wu (2016), these findings are not surprising. Yan et al. (2016) are of the opinion that enoxaparin does not compare to apixaban – with the latter being associated with better outcomes than the former. The only limitations to this study, unlike was the case with Raskob et al. (2012), is that the generalizability of its findings could be limited by its geographical limitation. However, unlike Yan et al. (2016), Raskob et al. (2012) left out an important variable, i.e. VTE-related mortality. This, in essence, limited the study’s applicability in a practice setting. The context of the study by Yen et al. (2016) was entirely China. Most studies cited in this text had a global context – with participants being of diverse racial, ethnic, and cultural extracts. However, unlike most authors, Yan et al. (2016) went further. They sought to determine how the two regimens compared on the cost effectiveness front. In a majority of cases, regimens with a higher efficacy rate tend to be also more costly than those reporting lower rates of efficacy. This assertion is upheld by Yen et al. (2016) who concluded that in comparison to apixaban, enoxaparin came across as being more cost effective. It should, however, be noted that there is need for additional research on the said cost effective claim given that the study by Yen et al. (2016) is largely limited to a specific geographical location, hence lacking in global applicability.
Most studies seeking to measure major bleeding in the context of the issue under consideration have also found apixaban to be more effective than enoxaparin. According to Raskob, Gallus, Pineo, Chen, Ramirez, Wright, and Lessen (2012), in comparison to enoxaparin where 0.8% patients experienced major bleeding, this affected approximately 0.7% of apixaban patients. This finding is supported by Lassen et al. (2010) who also found that apixaban helped in the minimization of bleeding. In essence, both findings are in consistence with the conclusions of Lassen et al. (2010) whose study reported 4 percent non-major bleeding for those on apixaban, in comparison to 5 percent for those on enoxaparin. Unlike most studies cited herein, however, Lessen et al. (2010) do not make use of a double-blind, randomized controlled trial (RCT). It is important to note that for a study of this nature, with comparisons between two regimens being drawn, an experimental design would have been more appropriate.
How apixaban compares to enoxaparin following discharge form the hospital has also been investigated in various studies. One such study came to a conclusion contrary to findings cited elsewhere in this text. In their research piece titled, Apixaban versus enoxaparin for thromboprophylaxis in medically ill patients, Goldhaber, Leizorovicz, Kakkar, Haas, Merli, Knabb, and Weitz (2011) came to the surprising conclusion that enoxaparin was superior to apixaban when it came to the prolonging of prophylaxis following release from the hospital. The results in this case fly contrary to the hypothesis, and hence expectations, of the authors of this particular research. It should, however, be noted that the study in this case largely concerns itself with those at risk of VTE as a consequence of congestive heart failure or other conditions of a similar nature. Its findings, therefore, do not have general comparability to those of studies highlighting how both regimens compare in situations involving major joint surgery – i.e. hip and knee replacements. Also, unlike is the case with other studies cited herein, the authors of this particular piece do not clearly define the sampling methods. It is also important to note that unlike was the case in Goldhaber et al., (2011), participants in studies cited herein, (i.e. by the likes of Lessen et al. and Pannucci et al., amongst others), were relatively healthy people, save for the need to undergo a knee or hip replacement surgery. Participants in Goldhaber et al., (2011) study were classified as being medically ill, effectively distinguishing the parameters of this particular study to those of studies cited in this text – therefore increasing the changes of differing outcomes.
It is important to note that enoxaparin has also fared poorly in other studies seeking to gauge its effectiveness in the prevention of uncontrolled bleeding after operation. One such study was undertaken by Pannucci et al. (2011). The authors found out that enoxaparin had no meaningful impact on hematomas rate. Although this particular study does not concern itself specifically with VTY, its findings on how effective enoxaparin is in the prevention of uncontrolled bleeding confirms the findings of Raskob et al. (2012) and Lassen et al. (2010) who find apixaban more effective when it comes to the prevention of post-operative bleeding following hip replacement surgery. The findings are further reinforced by Lassen et al. (2010) who set about to determine how effective apixaban is, in comparison to enoxaparin, in the control of post-operative bleeding following major joint surgery. Like those cited above, Lessen et al. (2010) are in agreement that apixaban is more effective on this front as well. However, unlike other cited authors, the authors in this case go further and define the optimal dosage for maximum benefit. The authors point out that 2.5 mg of apixaban is more effective in the control of post-operative bleeding following major joint surgery, in comparison to 40mg of enoxaparin. As Trkulja (2016) points out, the pharmacokinetic properties of apixaban are mostly favorable; specifically with regard to time and dose linearity, several pathways of elimination, and low variability (intrasibject and intersubject).
This synthesis clearly demonstrates the superiority of apixaban over enoxaparin. In essence, apixaban’s primary approval is for VTE prevention following major joint operation, i.e. knee and hip replacement. As Trkulja (2016) points out, the drug is, however, also approved for systemic embolism and stroke prevention amongst persons known to suffer from nonvalvular atrial fibrillation. There is need for comparison between the effectiveness of apixaban and other anticoagulant drugs; as well as between enoxaparin and other anticoagulant drugs. This would be of great relevance to the current practice of nursing as in addition to ensuring that nurses embrace the most effective approaches towards the management as well as prevention of VTE, it would aid in the identification of inefficiencies in current practice so that corrective measures can be adopted or implemented. Towards this end, the two regimens highlighted in this synthesis could, as Lassen et al. (2010) suggest, be compared to rabigatran and rivaroxaban regimens at various doses.
In the final analysis therefore, it is important to note that based on the synthesis above, apixaban appears to be safer as well as more effective than enoxaparin as VTE regimens after hip replacement surgery. It should also be noted that although this review was steeped towards VTE regimens following hip replacement surgery, its conclusions would be applicable to hip replacement surgery as well in which case apixaban appears to be not only safer, but also more effective than enoxaparin. Further, the findings of the synthesis seem to suggest that apixaban could have fewer limitations in comparison to conventional thromoprophylactic agents. Some of the said limitations have got to do with factors such as administration routes. The findings, as has been pointed out elsewhere in this text, also have applicability in practice. Enoxaparin, however, still remains applicable as an alternative to apixaban. This is more so where there are concerns as regards cost (with Yen et al. (2016) concluding that enoxaparin was more cost effective than apixaban). Its effectiveness in the prevention of VTE amongst those who undergo plastic surgery has also been upheld by Pannucci et al. (2011).




























References
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Lassen, M. R., Raskob, G. E., Gallus, A., Pineo, G., Chen, D., & Hornick, P. (2010). Apixaban versus enoxaparin for thromboprophylaxis after knee replacement (ADVANCE-2): a randomized, double-blind trial. The Lancet, 375(9717), 807–815. https://doi.org/10.1016/S0140-6736(09)62125-5
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