Positive Patient Postoperative Outcomes with Pharmacotherapy: A Narrative Review including Perioperative-Specialty Pharmacist Interviews

The influence of pharmacotherapy regimens on surgical patient outcomes is increasingly appreciated in the era of enhanced recovery protocols and institutional focus on reducing postoperative complications. Specifics related to medication selection, dosing, frequency of administration, and duration of therapy are evolving to optimize pharmacotherapeutic regimens for many enhanced recovery protocolized elements. This review provides a summary of recent pharmacotherapeutic strategies, including those configured within electronic health record (EHR) applications and functionalities, that are associated with the minimization of the frequency and severity of postoperative complications (POCs), shortened hospital length of stay (LOS), reduced readmission rates, and cost or revenue impacts. Further, it will highlight preventive pharmacotherapy regimens that are correlated with improved patient preparation, especially those related to surgical site infection (SSI), venous thromboembolism (VTE), nausea and vomiting (PONV), postoperative ileus (POI), and emergence delirium (PoD) as well as less commonly encountered POCs such as acute kidney injury (AKI) and atrial fibrillation (AF). The importance of interprofessional collaboration in all periprocedural phases, focusing on medication management through shared responsibilities for drug therapy outcomes, will be emphasized. Finally, examples of collaborative care through shared mental models of drug stewardship and non-medical practice agreements to improve operative throughput, reduce operative stress, and increase patient satisfaction are illustrated.

Review of Prothrombin Complex Concentrates Use in Apixaban and Rivaroxaban Associated Intracranial Hemorrhages

STUDY OBJECTIVE

Summarize the studies evaluating the use of 4-factor prothrombin complex concentrates in the management of apixaban and rivaroxaban associated intracranial hemorrhages.

METHODS

A PubMed literature search was conducted for articles published between 2013 and 2020 which contained the following terms in their title: (1) apixaban, rivaroxaban, or factor Xa inhibitor*, and (2) prothrombin complex concentrate*.

RESULTS

Eighteen observational studies were included. When a ∼25 units/kg (range: 25-26.9 units/kg) non-activated 4 factor prothrombin complex concentrate dose was administered, the hemostatic effectiveness rates were ≥ 79% in 2/4 studies that utilized the Sarode et al criteria, in comparison to 4/5 studies that administered a 50 units/kg dose. The mortality rates were < 20% in 7/9 studies with hemostatic effectiveness rates ≥ 79%. Mortality rates were lower in the studies demonstrating higher hemostatic effectiveness rates and including patients with higher Glasgow coma scale scores and lower intracerebral hemorrhage volumes. Overall, the thromboembolic event rates were 0-18%, with 16/18 studies demonstrating rates ≤ 10%. The thromboembolic event rates were not dose or agent dependent.

CONCLUSION

Rates of hemostatic effectiveness were influenced by the definition of hemostatic effectiveness, dose administered, and patient severity. Studies suggest that higher doses may result in higher hemostatic effectiveness rates without increasing the risk of experiencing a thromboembolic event. This review may be used by providers to modify or validate their reversal strategy approach until well designed studies are available.

Effects of Obesity on Warfarin Reversal With Vitamin K

Phytonadione (vitamin K1, VK) is fat soluble and may be sequestered by adipose tissue, thus potentially altering drug distribution in obese patients requiring warfarin reversal. This single-center retrospective cohort study aimed to determine the effects of obesity (defined as body mass index [BMI] ≥ 30 kg/m²) on warfarin reversal following administration of VK in adult patients. The primary outcome was complete or partial warfarin reversal (defined as an international normalized ratio [INR] ≤ 2.0) within 72 hours post-VK administration. Of 688 identified patients, 215 were included in primary INR analysis. Mean BMIs for obese (n = 84) and nonobese (n = 131) patients were 37.3 and 24.3 kg/m² ( P < .001), and mean baseline INRs were 4.73 and 4.42 ( P = .534), respectively. Within 72 hours post-VK administration, 70% and 69% of the obese and nonobese groups, respectively, achieved complete or partial warfarin reversal ( P = .904). Multiple logistic regression determined baseline INR and concomitant fresh frozen plasma administration to be factors influencing warfarin reversal. These findings do not suggest obesity is significantly associated with a decreased likelihood of warfarin reversal within 72 hours post-VK administration.

Clinical Application of Prothrombin Complex Concentrate in Blood Management in Patients

Management of patients receiving anticoagulants is a major factor in achieving better outcomes. Anticoagulant therapy may need to be discontinued or rapidly reversed before urgent surgery or invasive procedures. In these situations, treatment with concentrated vitamin K, fresh frozen plasma, and/or clotting factors can achieve more rapid anticoagulant reversal than can drug discontinuation alone. Activated prothrombin complex concentrate is used to treat hemophiliac patients with acquired factor VIII inhibitors. Nonactivated prothrombin complex concentrates are used for anticoagulant reversal. The concentrates are effective within minutes of dosing, providing a nearly immediate decrease in the international normalized ratio. The concentrates are lyophilized powders that can be quickly reconstituted, do not require ABO blood typing before use, and contain 25 times the concentration of vitamin K-dependent clotting factors compared with fresh frozen plasma. Studies suggest that the concentrates are associated with better clinical end points than is fresh frozen plasma.

Reversal agents for use with direct and indirect anticoagulants

PURPOSE

The properties of three oral anticoagulant-specific reversal agents are reviewed, and guidance is presented to assist pharmacists in planning for the agents' introduction to the market.

SUMMARY

Idarucizumab, which received Food and Drug Administration approval in October 2015, is a humanized monoclonal antibody fragment that immediately neutralizes the anticoagulant effect of dabigatran, as evidenced by reduced unbound dabigatran concentrations and normalized coagulation tests. Preliminary Phase III trial results demonstrated a median maximum reversal of 100%, a median time to bleeding cessation of 11.4 hours, and normal intraoperative hemostasis in 92% of patients requiring anticoagulation reversal before an urgent procedure. Andexanet alfa is a factor Xa (FXa) decoy that binds to direct and indirect FXa inhibitors. In Phase III trials in healthy volunteers, andexanet alfa reduced anti-FXa activity by more than 90%, reduced the concentration of unbound direct FXa inhibitor, and inhibited thrombin generation. Ciraparantag is a reversal agent under development for reversal of anticoagulation with direct and indirect FXa inhibitors and certain factor IIa inhibitors; it exerts its effect through hydrogen bonding. Concerns for thromboembolic events directly related to administration of idarucizumab, andexanet alfa, or ciraparantag have not arisen. Pharmacists need to begin preparing for the introduction of these specific reversal agents through protocol development and provider education; in addition, pharmacy departments need to plan for procurement and storage. The specific reversal agents should be incorporated into antithrombotic stewardship or other clinical pharmacy programs for surveillance.

CONCLUSION

As agents that provide rapid reversal of direct oral anticoagulant activity become available, advance planning will help hospitals to optimize their use.

Reversal of anticoagulation with four-factor prothrombin complex concentrate without concurrent vitamin K (phytonadione) for urgent surgery in a patient at moderate-to-high risk for thromboembolism

Successful vitamin K antagonist (eg, warfarin) reversal with 4-factor prothrombin complex concentrate (4F-PCC) without vitamin K (phytonadione) for emergent surgery in a patient at moderate-to-high risk for thromboembolism is reported. This approach may decrease the risk for development of thrombus, as it limits the amount of time the patient's anticoagulation is subtherapeutic. It also may increase the risk of bleeding, so patient selection is essential if this strategy is employed. Caution must be exercised to complete the procedure or surgery in the window of peak 4F-PCC effect (∼1-6 hours postinfusion).

Efficacy of prothrombin complex concentrates for the emergency reversal of dabigatran-induced anticoagulation

Dabigatran is effective in decreasing the risk of ischaemic stroke in patients with atrial fibrillation. However, like all anticoagulants, it is associated with a risk of bleeding. In cases of trauma or emergency surgery, emergency reversal of dabigatran-induced anticoagulation may be required. A specific reversal agent for dabigatran, idarucizumab, has been approved by the US Food and Drug Administration. Alternative reversal agents are available, such as prothrombin complex concentrates (PCCs) and activated PCCs (aPCCs). In this review we evaluate the role of PCCs and aPCCs in the reversal of dabigatran anticoagulation and consider which tests are appropriate for monitoring coagulation in this setting. Pre-clinical studies, small clinical studies and case reports indicate that PCCs and aPCCs may be able to reverse dabigatran-induced anticoagulation in a dose-dependent manner. However, dosing based on coagulation parameters can be difficult because available assays may not provide adequate sensitivity and specificity for measuring anticoagulation induced by dabigatran or the countering effects of PCCs/aPCCs. In addition, PCCs or aPCCs can potentially provoke thromboembolic complications. Despite these limitations and the fact that PCCs and aPCCs are not yet licensed for dabigatran reversal, their use appears to be warranted in patients with life-threatening haemorrhage if idarucizumab is not available.

Managing bleeding and emergency reversal of newer oral anticoagulants: a review for primary care providers

The therapeutic landscape for anticoagulation management is undergoing a shift from the use of traditional anticlotting agents such as heparins and warfarin as the only options to the growing adoption of newer target-specific oral anticoagulants (TSOACs) with novel mechanisms of action. Dabigatran, the first TSOAC approved for use in the United States, is a direct competitive inhibitor of thrombin. It has predictable kinetics, with an elimination half-life of 12 to 17 hours in healthy volunteers. Apixaban and rivaroxaban are selective inhibitors of factor Xa, and also display first-order kinetics. In younger healthy individuals, apixaban has an apparent half-life of approximately 12 hours, whereas rivaroxaban has an elimination half-life of 5 to 9 hours. Understanding the pharmacologic properties of these newer drugs can lead to better insights regarding their respective safety and efficacy profiles and their application in clinical practice. Laboratory assessments have been developed to measure the anticoagulant efficacy of these newer agents. However, the results of these tests can be highly variable, and are therefore not always useful for monitoring the anticoagulation effects of these agents. In addition, several strategies have been documented for the potential reversal of the anticoagulant effects of these drugs, from the temporary discontinuation of an agent before elective surgery to suggested emergency procedures in the case of major bleeding events. New, specific reversal agents for dabigatran, apixaban, and rivaroxaban are currently being developed, and dabigatran has received fast-track designation from the US Food and Drug Administration. Until comprehensive clinical guidelines are developed, institutions involved in emergency care should establish their own procedures for the management of patients undergoing anticoagulation who require emergency treatment. These protocols should include appropriate laboratory testing to assess anticoagulant activity as part of the inpatient workup if time allows, and the potential use of hemodialysis, prohemostatic agents, and reversal agents when available.

Strategies for urgent reversal of target-specific oral anticoagulants

The direct thrombin inhibitor dabigatran and factor Xa inhibitors rivaroxaban and apixaban are US Food and Drug Administration (FDA)-approved target-specific oral anticoagulants (TSOACs) that have emerged onto the market for use in some indications similar to those for warfarin; in addition, edoxaban is seeking FDA approval. Similar indications include reducing the risk of stroke and systemic embolism in patients with nonvalvular atrial fibrillation for all 3 agents, for the prevention of deep vein thrombosis that may lead to pulmonary embolism in patients undergoing hip or knee surgery for rivaroxaban and apixaban, and for the treatment and prevention of deep vein thrombosis and pulmonary embolism. As anticoagulants, they are all associated with a risk of bleeding, and, unfortunately, there are no approved antidotes for reversal of these agents. A number of small studies in human subjects and in human/animal models exposed to TSOACs have evaluated the use of activated charcoal, hemodialysis for dabigatran, or clotting factor concentrates for their ability to neutralize the anticoagulant effects or reduce drug concentrations of TSOACs. Clotting factor concentrates that have been used include prothrombin complex concentrates and recombinant factor VII. This review examines studies and case reports evaluating these strategies for expedited or emergent reversal of TSOACs.

Management of bleeding and reversal strategies for oral anticoagulants: clinical practice considerations

PURPOSE

Currently available clinical data and optimal strategies for reversing oral anticoagulants in patients who are bleeding or need an urgent invasive procedure or operation are reviewed.

SUMMARY

Bleeding from oral anticoagulants, including new target-specific oral agents (TSOAs), is a common cause of morbidity and mortality, especially in elderly patients. Limited clinical data are available to guide the reversal of warfarin or TSOAs in patients who are bleeding or need an urgent invasive procedure or operation. A panel of five experts with diverse backgrounds in anticoagulation therapy, cardiology, critical care, and emergency medicine and with experience in managing complications of anticoagulation therapy was convened to develop practical strategies for managing patients receiving oral anticoagulants who are bleeding or have an urgent need for an invasive procedure. The strategies were designed to guide clinicians in the acute care setting by providing efficient and potentially effective management concepts to avoid delays in initiating treatment that could adversely affect patient outcomes. The consensus of this expert panel is summarized herein. Recommendations are based on currently available evidence from a comprehensive review of the literature and other pertinent data, along with the experience and expert opinion of the panelists.

CONCLUSION

Bleeding is a serious complication of the use of oral anticoagulants, and limited information is available to guide the reversal of warfarin or TSOAs in patients who are bleeding or are in need of an urgent invasive procedure. Use of a systematic approach to assessing and treating these patients based on available evidence and expert opinion can help avoid delays that could adversely affect patient outcomes.

A new paradigm shift in antithrombotic therapy

Decades after the introduction of oral anti-coagulants namely the vitamin K antagonist (VKA) Warfarin and antiplatelet agents such as Aspirin and Plavix, new classes of direct, small molecule, novel oral anti-coagulant medications and antiplatelet P2Y12 receptor inhibitors have recently become available. For the novel oral anticoagulants (NOAC), these agents can be separated by direct thrombin inhibitors such as Dabigatran and direct Factor Xa inhibitors such as Rivaroxaban and Apixaban. For next generation antiplatelet agents such as Ticagrelor and Prasugrel, these new P2Y12 receptor inhibitors form the cornerstone of therapy for patients with acute coronary syndrome (ACS) or undergoing percutaneous interventions. These novel oral antithrombotics are revolutionizing the field of stroke prevention, atrial fibrillation (AF), the management of venous thromboembolism (VTE) and treatment of ACS. This article reviews the current research developed in order to identify therapeutic effects and establish net clinical benefits of these new oral antithrombotics.