Knowledge of DOAC levels may reduce delay to surgery

There is a delay in getting elderly patients with acute hip fracture to surgery when they present on DOACs compared to patients on warfarin and antiplatelets, Australian research shows.

A WA study of 1,240 patients presenting to one of the three tertiary hospitals in Perth found 11.8% were on an anticoagulant – 5.1% of warfarin and 6.7% on a DOAC, most commonly apixaban.

More than half the patients (58.2%) were not receiving any anticoagulant or antiplatelet agent while 29.8% were receiving an antiplatelet agent. Use of dual therapy was a low 1.1%.

The study found the time to surgery was significantly longer for those patients on a DOAC compared to those on warfarin (43.9 v 27.9 hours; P = 0.003).

Overall, patients on any anticoagulation but not antiplatelets also had a longer delay before surgery than those not on anticoagulation.

The study found no significant differences in the change of haemoglobin after surgery or in transfusion requirements between patients on DOACs or those on warfarin.

In patients for whom preoperative DOAC levels were available, about half (52%) had levels ≤50ng/mL within 12 hours of presentation.

“Our results suggest that if DOAC levels were performed regularly on presentation, and if a threshold of ≤ 50ng/mL were accepted as safe for surgery, then a significant proportion of patients on DOAC therapy will be able to undergo operative management within 24 hours of presentation,” the study said.

Lead author Dr Katherine Creeper, a haematology trainee at Sir Charles Gairdner Hospital at the time of the study, told the limbic that WA was in the privileged position of having 24 hour access to DOAC levels at the three tertiary hospitals.

“The pertinent finding in our study was that a lot of patients had low levels of DOAC on board so potentially the delay to surgery is unnecessary.”

This was especially important given most of the hip fractures in the state are performed in Perth, “so there is already another 1 or 2 days delay because it takes a while to get from say Kununurra down to Perth,” she said.

“Obviously there were quite a few confounding factors. The trouble is some studies say you should operate on hip fracture patients in 24 hours and some say 48 hours ….but the sooner you get them to theatre the better, is generally what the studies show.”

Dr Creeper said the three hospitals originally had different policies with one recommending drug levels and proceeding to theatre if the DOAC level was <50ng/mL; another performing a bleeding assessment utilising DOAC dose, time of last dose and projected clearance based on renal function, and not recommending DOAC levels; and the third utilising both bleeding assessment and DOAC levels.

“Our practice is changing now such that if anyone comes in on a DOAC we routinely get a DOAC level just to see where we’re at and guide management because we are getting more comfortable about interpreting them.”

“It doesn’t make sense in WA to have three different protocols particularly when some of the junior staff and orthopaedic registrars rotate between them all. It just makes sense to have everyone on the same page.”

She said in patients with levels >50ng/mL, they would wait for wash out of the DOAC and get a repeat level 24 hours later.

“I don’t think there is any evidence to give prothrombinex or any of the reversal agents – normally they are only for life-threatening bleeding which this wouldn’t be an indication for.”

“I think as we use these drugs more, we are going to get more comfortable with interpreting these levels,” she said.

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