August 2023

‍Report from a very smokey Montreal ISTH meeting

There was a bouncy lady gymnast doing aerials from a bendy strip of wood held up by 2 men. A guy in a shiny space suit with dark goggles dazzling the audience with coloured laser beams. Another muscular guy with a large metal frame which he tossed around like it was easy. Magical performances; probably not surprising in the city where Cirque du Soleil originated.  

Then there was the Canadian “welcome to country” and finally the opening lecture by Bjorn Dahlback on 40 years of looking into the gymnastics of the factor V molecule. After that a feast of Quebec specialities including Putine (French fries and cheese drenched in gravy=delicious?).

Attendance at the ISTH meeting in Canada was back to pre-Covid levels. Main topics were post covid effects on haemostasis, FVIII replacing agents, new ideas about reversing DOACs and increasing uses of DOACs in various clinical circumstances. I focused on diagnostics and couldn’t help asking why are all the researchers getting younger?

DOAC-Stop™ hits the spot

There were 6 abstracts reporting laboratory studies with our own DOAC-Stop™ (DS) diagnostic aid. Five of these are summarized below. Also, one on our HRRS (now trademarked as Antihepca™). We are most grateful to all those researchers who carried out these unsolicited, but most useful projects described briefly below.

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1. Diane Zebeljan, Geoff Kershaw, Penny Motum and S Ng from Liverpool Hospital described 2 cases of high dabigatran levels causing false low fibrinogen results with the thrombin-based von Clauss method. Not surprising given the rather high levels of this thrombin inhibitor, up to 2181ng/ml in one case and 4422ng/ml in another. DS was effective in correcting fibrinogen results and ultimately PT and APTT in the second case. Two doses of Praxbind dabigatran reversal agent provided only partial neutralization.
https://academy.isth.org/isth/2023/isth-2023-congress/382261/sara.ng.high.plasma.dabigatran.levels.causing.falsely.low.fibrinogen.results.a.html
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2. Marc Ellis, C Durivage, P Gounder, Maria Konda and Prof Vivien Chen at RPAH/Concord hospital described a difficult, complex case of a F71 with a mitral valve and risk of HITT being bridged from argatroban to warfarin anticoagulation. Sample pretreatment with DS effectively removed argatroban, thereby providing more specific INR and APTT results. Kent Chapman (John Hunter Hopsital, Newcastle) described a similar case just a while ago. Argatroban is chemically similar to the DOACs. It may not be absorbed orally but is readily adsorbed by DS.
https://academy.isth.org/isth/2023/isth-2023-congress/382262/vivien.chen.use.of.doac-stop.to.guide.warfarin.therapy.in.patients.receiving.html
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3. Ewa Wypasek, Adrian Klepzyk, Michal Zabcyk and Prof Anna Undas from the John Paul II Hospital in Krakow, Poland evaluated the impact of DS on lupus anticoagulant testing in 319 anticoagulated VTE patients. Excluding false positives from DOACs, dRVVT LA1/LA2 ratio >1.2 indicating positive lupus anticoagulant was found in 23 cases (7.2%). Still a high yield. This is the “largest cohort of VTE patients evaluated for LA with use of DS, showing reliability of such an approach in a real life setting”.  
https://academy.isth.org/isth/2023/isth-2023-congress/382162/anetta.undas.the.effect.of.doac-stop.on.lupus.anticoagulant.testing.in.plasma.html
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4. H Medforth, K Hickey and Steve Kitchen from the Hallamshire Hospital in Sheffield, UK evaluated and compared DOAC-Stop™ mini-tablets, DOAC Remove and DP Filter. All seemed to work well to remove DOACs which would otherwise interfere with lupus anticoagulant testing, especially with dRVVT tests. This expert group preferred DOAC-Stop™ because one minitablet could be used with a wider range of sample volumes (0.5-1.5ml per minitablet).
https://academy.isth.org/isth/2023/isth-2023-congress/382209/hazel.medforth.evaluation.of.charcoal.based.direct.oral.anticoagulant.28doac29.html
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5. Sunny Jamati from the Waikato Hospital, Hamilton, New Zealand presented work supporting the value of DOAC-Stop™ in removing supratherapeutic levels of dabigatran from samples. In one case from a patient with acute kidney injury. Also confirmed that DOAC-Stop™ also allowed valid performance of lupus anticoagulant and antithrombin testing. Probably of most value was her comment that DOAC-Stop™ can aid in determining the aetiology of a coagulopathy even when dabigatran is being used.
https://academy.isth.org/isth/2023/isth-2023-congress/382190/sunny.jamati.applications.of.doac.removal.in.the.laboratory.html
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6. There was also a poster on HRRS-our heparin resistant recalcifying solution (now called Antihepca™-HRRS) from the Sheffield hospital group. This is quite widely used in Australia, but is new to the rest of the world. Paula Brown and colleagues there showed that HRRS was highly specific for heparin in its shortening effect on APTTs. She reported it to be a simple, stable and low-cost method for heparin correction in various test plasmas. Was concerned about instrument variability and possible carry-over. We have had no reports on that after many years of local usage. If you know more, please let us know…
https://academy.isth.org/isth/2023/isth-2023-congress/382227/paula.brown.shortening.of.aptt.when.heparin.neutralising.calcium.solution.html
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More details are available from Haematex.

Thomas Exner

3/8/2023

PS: Our own poster on the subject of DOAC synergy is available - and features the use of our Go-DOAC™, test reagent. This is available here: https://academy.isth.org/isth/2023/isth-2023-congress/382204/thomas.exner.anticoagulant.activity.of.factor.xa-inhibiting.doacs.is.increased.html

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Haematex is the only Australian distributor which carries out local R&D into coagulation diagnostics. When you purchase from us, a portion of profits go towards projects such as our own locally made DOAC-Stop™, and research on dRVVT and lupus anticoagulants. We hope this newsletter has been of interest, if you do not wish to receive future updates, please let us know.

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