Real-world experience with idarucizumab for the reversal of dabigatran has highlighted the importance of monitoring coagulation tests particularly in patients with renal impairment.
Speaking at Blood 2018, final year haematology registrar Dr Yvonne Brennan reported on a retrospective audit of idarucizumab use and clinical outcomes in Western Sydney Local Health District.
The audit involved 24 doses of the reversal agent in 23 patients over two years 2015-2017. All patients were on dabigatran for atrial fibrillation.
Three quarter of patients required idarucizumab for major bleeding episodes – a third of which were for gastrointestinal bleeds. The other patients required reversal for urgent procedures.
There was little use of other prohaemostatic agents such as transexamic acid, vitamin K, platelets or fresh frozen plasma.
Half of the doses of idarucizumab were administered in the emergency department, 25% on the ward, three in ICU and two in the cardiac catheter laboratory due to pericardial effusion.
One of the patients with pericardial effusion subsequently required a second dose of idarucizumab but later died from cardiogenic shock.
Dr Brennan told the meeting that the reversal of dabigatran led to control of bleeding in most patients (88%).
Only 30% of all patients resumed therapeutic anticoagulation during their admission with at least another 17% recommencing dabigatran after discharge.
The audit revealed a range of practice regarding the ordering of coagulation tests or dabigratran levels.
In the patients with baseline coagulation tests, most (19 of 20) were shown to have prolonged thrombin times or activated partial thromboplastin times (APTT).
Twenty-four hours later, about half the bleeding patients and 25% of the patients requiring procedures still had prolonged thrombin times.
Five of the ten patients with coagulopathy at 24 hours subsequently died.
“Renal impairment at admission predicted prolonged TT/APTT at 24 hours,” Dr Brennan said.
“Only five patients had dabigatran levels measured at baseline and there are a couple of reasons for that. I think other doctors at the time were not familiar with the dabigatran testing at our centre or maybe they didn’t bother because it’s going to take ages for the drug level to come back.
Only three patients had dabigatran levels assessed at 24 hours.
Dr Brennan told the limbic that while it would have been nice to have dabigatran levels for audit purposes, in real life the results probably wouldn’t have changed management.
“You aren’t going to wait for the level to come back if someone is bleeding. You are just going to give the idarucizumab anyway. So that’s probably one of the reasons why dabigatran levels weren’t sent as often as one might assume.”
However levels were important for the rare patients who were continuing to bleed, were found to still have dabigatran in their system and might need a second dose of the reversal agent.
“So if there is ongoing bleeding, you have done your endoscopies and everything you can but they are still bleeding and have dabigatran on board, then they do need a second dose of idarucizumab.”
“And then because the study found that people with renal impairment had a higher chance of rebound dabigatran appearance, they are the group you should follow up closely with drug levels.”
Dr Brennan added the audit revealed some practical areas for improvement including occasional dosing, charting and dispensing errors.