Thread by @amarkelkar

Some current Hematologic diagnostic & management dilemmas of Adenovirus #JNJ & #AstraZeneca #VITT:
1⃣VITT seems to behave like autoimmune (Type 2) HIT rather than non-immune (Type 1) HIT (more common).
(Greinacher et al, @JTHjournal, 2017)
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#MedTwitter #HemeTwitter #COVID19

2⃣High enough doses of heparin or LWMH can outcompete these PF4-polyanion complexes for binding sites & reduce platelet aggregation (similar to HIT).
➡️BUT, we can't yet tell where/if there's a consistent dose breakeven point at which aggregation⬇️
(Schultz et al, @NEJM, 2021)
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➡️While many cases reported using LMWH (mostly low-dose Dalteparin), lab results were inconsistent on whether this sufficiently reduced/prevented platelet aggregation.

(Greinacher et al, @NEJM, 2021)
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➡️Even if there is, thrombocytopenia needs to be reversed at least somewhat or bleeding could worsen (particularly CNS bleeding), so treatment with high-dose IV steroids and IVIg (1g/kg daily IV for 2 days) may be key to treatment.
(Greinacher et al, @NEJM, 2021)
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3⃣Given the highly positive PF4-polyanion IgG optical density in VITT, is there any indication to send "confirmatory" (e.g., serotonin release assay) testing? It seems to me like that is not necessary, but I suspect most centers will still send it.
(Schultz et al, @NEJM, 2021)
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4⃣Is there Vaccine-induced Thrombocytopenia (VIT, i.e., adenovirus vaccine-related thrombocytopenia) without VITT happening more often, like what we see in HIT versus much rarer HITT? Is it silent in many cases since we're not checking CBCs regularly on typical patients?
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➡️I couldn't find Grade 3/4 thrombocytopenia reported in any of the Ad26.COV2.S studies/supplements, but there were 7 cases of thrombocytopenia in @CDCgov VAERS as of Friday, April 9 (system updates QW). So far, there doesn't seem to be a VIT pattern.
(wonder.cdc.gov)
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5⃣Discharge anticoagulant of choice in Schultz et al was warfarin, but Greinacher et al reported apixaban use (anti-Xa-inh). @ASH_hematology 2018 HIT Guidelines had a conditional recommendation for AC to include DOACs
(Cuker et al, @BloodAdvances, 2018)
8/ ashpublications.org/blood/article/…

I'd love to hear other Hematologists' thoughts, particularly on the possibility of adenovirus VIT😣... @JonRob08 @CukerMd @MPaiMD @connors_md @NTConnell @PedsHemeDoc @acweyand @hematologydoc_O @JenniferYuiMD @Bloodman @CarolMathewMD @DrMMurphy @PKouides @MattCheungMD @bhwords
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I'll be anxiously awaiting the inevitable Hematology brain-trust review/commentary like what was previously discussed when there was a prior concern for immune thrombocytopenia in @pfizer and @moderna_tx vaccines.
(Lee et al, AJH @WileyOnc_Hem, 2021)
onlinelibrary.wiley.com/doi/10.1002/aj…
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A review of yesterdays @CDCgov Advisory Council on Immunization Practices (#ACIP) meeting ... tl;dr ACIP didn't make any recommendation, effectively recommending that the pause on #JNJ vaccine delivery be extended 7-10 days for additional data review. 11/

https://twitter.com/amarkelkar/status/1382461992368287746?s=20

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