Use of Specific Inhibition of Anticoagulant Therapy During Heart Transplantation

Anticoagulation in Patients with CHF

In patients with chronic heart failure (CHF), atrial fibrillation is a common complication, which is an indication for prophylactic anticoagulant therapy. Patients with CHF who need a heart transplant are still very often prescribed vitamin K antagonists (VKAs). However, the European Society of Cardiology (ESC) recommends using direct oral anticoagulants (DOACs) in these patients due to their overall clinical benefit, positive impact on survival, and better safety profile despite the risks during surgery. If bleeding occurs, blood transfusions and fluid replenishments are administered, and for VKAs, vitamin K is also given. In cases of life-threatening bleeding, a prothrombin complex concentrate or fresh frozen plasma is administered, and if available, a direct antidote. The antidote for DOAC dabigatran is idarucizumab, a monoclonal antibody fragment that binds to dabigatran and blocks its anticoagulant effect, i.e., thrombin inhibition.

Findings from an Observational Study

A cohort of 10 patients with heart failure from various causes (dilated, ischemic, restrictive, and hypertrophic cardiomyopathy, valvular disease) who were long-term users of dabigatran and were administered 5 g of idarucizumab before heart transplantation was observed. The average concentration of dabigatran in plasma was 139 ± 89 ng/ml. During cardiopulmonary bypass, unfractionated heparin (mean 28,711 ± 9,830 IU) was administered, and anticoagulation was monitored using activated clotting time. Before detachment, anticoagulation was stopped using protamine sulfate (mean 11,111 ± 7,927 IU). After surgery, a decrease in hemoglobin, hematocrit, and blood platelets was observed. The surgical procedures were successfully performed without increased risks. All patients were alive 30 days post-procedure, and during hospitalization, none experienced reoperation due to bleeding into the chest cavity, nor did any suffer thrombotic complications.

The results were compared with a historical cohort of patients who were administered VKA before heart transplantation (n = 24). Patients treated with dabigatran/idarucizumab needed fewer units of transfusion products during perioperative and postoperative intensive care compared to patients on VKA (2.2 ± 2.52 vs. 8.57 ± 10.56; p < 0.001). There was no difference between the groups regarding the administration of autologous transfusions.

Conclusion

The use of idarucizumab to inhibit the anticoagulant effect of dabigatran appears to be a suitable and safe alternative even in patients awaiting heart transplantation with an indication for anticoagulant therapy.

(eko)

Source: Kalmanovich E., Battistella P., Rouviere P. et al. Idarucizumab (Praxbind^®) for dabigatran reversal in patients undergoing heart transplantation: a cohort of ten patients. Future Sci OA 2021 Feb 15; 7 (4): FSO689, doi: 10.2144/fsoa-2020-0186.