Andexanet Alfa Use in Patients Requiring Cardiopulmonary Bypass: Quo Vadis?

Recommendations for the use of andexanet alfa in the management of bleeding in patients on oral factor Xa inhibitors in Switzerland: Guideline from the Working Party Hemostasis of the Swiss Society of Hematology

Anticoagulants are essential in preventing and treating thrombosis. Unfortunately, their use is accompanied by an enhanced risk of bleeding. Since the introduction of direct oral anticoagulants (DOACs), the risk of major bleeding has been reduced but not eliminated. Major bleeding events related to the use of factor Xa inhibitors can be challenging to manage. In recent years, four-factor prothrombin complex concentrates have been used in patients with severe bleeding taking oral direct factor Xa inhibitors (apixaban, edoxaban and rivaroxaban). Andexanet alfa (OndexxyaTM, AstraZeneca AG) is a specially designed recombinant version of human factor Xa that acts as a decoy receptor to reverse the effects of factor Xa inhibitors. Since 2 December 2020, andexanet alfa has been used in Switzerland for adult patients receiving apixaban or rivaroxaban when reversal of anticoagulation is required because of life-threatening or uncontrolled bleeding. However, the use of andexanet alfa remains a challenge owing to its cost, the reported thrombotic complications and the fact that its efficacy mainly relates to intracranial haemorrhage. Moreover, the use of nonspecific reversal agents together with andexanet alfa is controversial. The present recommendations on the use of andexanet alfa in the management of bleeding in patients on factor Xa inhibitors in Switzerland were developed by a group of Swiss experts from the Working Party Hemostasis of the Swiss Society of Hematology. These recommendations aim to provide support to clinicians in their decision-making in the management of patients with major bleeding receiving factor Xa inhibitors.

Contemporary Perioperative Management of Direct Oral Anticoagulants

Direct oral anticoagulants (DOACs) have rapidly emerged as popular alternatives to warfarin in the setting of nonvalvular atrial fibrillation, prevention and treatment of venous thromboembolism, and secondary prevention of arterial thrombosis. It is now estimated that more patients in the United States take DOACs than warfarin for approved indications. Studies to date have shown that these drugs are similarly efficacious with perhaps a lower bleeding risk than warfarin. The purpose of this review is to provide insight into the currently available DOACs and discuss the management and reversal strategies for patients in the perioperative period.

Heparin Insensitivity and Thrombotic Risk Associated With Sequential Uses of Prothrombin Complex Concentrate and Andexanet Alfa for Apixaban Reversal During Acute Type A Aortic Dissection Repair: A Case Report

The management of patients on direct oral anticoagulants (DOACs) who require emergent cardiac surgery is slowly evolving. The introduction of andexanet alfa, a novel antidote for apixaban and rivaroxaban, added a specific reversal agent to our armamentarium, but its safety and efficacy are still being investigated. We report 2 patients on DOAC treatment who required emergency cardiac surgery. Both received perioperative andexanet alfa together with prothrombin complex concentrate (PCC) at some time during 6 hours before operative management. Heparin resistance was noted in each instance, and pump thrombosis developed in 1 case.

Perioperative Management of Direct Oral Anticoagulants in Cardiac Surgery: Practice Recommendations Based on Current Evidence

An increasing number of patients on systemic oral anticoagulants present for cardiac surgery, and cardiac anesthesiologists should be well-informed on their management in the perioperative period. Direct oral anticoagulants (DOACs), including factor Xa inhibitors and direct thrombin inhibitors, are an attractive alternative to warfarin due to fewer dietary and drug interactions, less frequent monitoring requirements, and an improved patient adherence. Since the approval of DOACs by the Food and Drug Administration in 2010, the number of patients on these medications only has increased. The guidelines vary on the periprocedural management of DOACs for cardiac surgery. This review evaluated the current evidence for medication cessation before surgery, based on timing as well as plasma drug concentration. The practice recommendations of various monitoring tests and new evolving point-of-care testing are examined herein. The different reversal agents were discussed by the authors for both elective and urgent procedures. The cardiac anesthesiologist needs to be intimately familiar with the management and current best practices of DOACs for safe and appropriate patient care.

Andexanet-Alfa-Associated Heparin Resistance in the Context of Hemorrhagic Stroke

Background

With a growing number of patients on new oral anticoagulants, interest in reversal agents is rising. Andexanet alfa is used for reversal of factor Xa inhibitors in intracranial hemorrhage.

Methods

We provide a brief review on andexanet-alfa-associated heparin resistance and discuss potentially critical situations from different clinical perspectives.

Results

Case reports point out that andexanet alfa can cause unresponsiveness to heparin, leading to catastrophic events. As a result, regulatory bodies have issued warning notices to avoid heparinization parallel to the use of andexanet alfa.

Conclusions

Although well known to hematologists, the phenomenon is underrecognized among stroke clinicians. However, patients with intracranial hemorrhage frequently undergo endovascular or surgical interventions that require periprocedural administration of heparin.

Emergency cardiac surgery in patients on oral anticoagulants and antiplatelet medications

BACKGROUND

Emergency surgery, blood transfusion, and reoperation for bleeding have been associated with increased operative morbidity and mortality. The recent increased use of direct oral anticoagulants and antiplatelet medications has made the above more challenging. In addition, cardiopulmonary bypass (CPB), with its associated hemodilution, fibrinolysis, and platelet consumption, may exacerbate the pre-existing coagulopathy and increase the risk of bleeding.

AIM

The aim of this study was to examine available literature with regard to treating patients who are on the above medications and require emergency cardiac surgery.

RESULTS

Management decisions are typically made on a case-by-case basis. Surgery is delayed when possible, and less invasive percutaneous options should be considered if feasible. Attention is paid to exercising meticulous techniques, avoiding excessive hypothermia, and treating coexisting issues such as sepsis. Ensuring a dry operative field upon entry by correcting the coagulopathy with reversal agents is offset by the concern of potentially hindering efforts to anticoagulate the patient (heparin resistance) in preparation for CPB, in addition to possibly increasing the risk of thromboembolism.

CONCLUSION

Proper knowledge of anticoagulants, their reversal agents, and the usefulness of laboratory testing are all essential. Platelet transfusion remains the mainstay for antiplatelet medications. Four-factor prothrombin complex concentrate is considered in patients on oral anticoagulants if CPB needs to be instituted quickly. Specific reversal agents such as idarucizumab and andexanet alfa can be considered if significant tissue dissection is anticipated, such as redo sternotomy, but are costly and may lead to heparin resistance and anticoagulant rebound.