PB0324 - Alternative anticoagulant treatment in patients with Heparin Induced Thrombocytopenia (HIT). Experience in a high complexity center according to anticoagulants local availability.

Sunday, July 10, 2022

6:30 PM – 7:30 PM

Location: Exhibition

Presentation Format: In-Person

Presenting Author(s)

Veronica Privitera

MD
Hospital Italiano de Buenos Aires
Ciudad Autónoma de Buenos Aires, Ciudad Autonoma de Buenos Aires, Argentina

Co-Author(s)

MG

Melina Garbarini

MD
Hospital Italiano de Buenos Aires
Ciudad Autonoma de Buenos Aires, Ciudad Autonoma de Buenos Aires, Argentina
CF

Chuliber Fernando, MD

MD Hematologist
Grupo CAHT
Buenos Aires, Ciudad Autonoma de Buenos Aires, Argentina
MV

Maximiliano Villagra Iturre

MD
Hospital Italiano de Buenos Aires
Buenos Aires, Ciudad Autonoma de Buenos Aires, Argentina
VP

Veronica Privitera

Biochemist
Central Laboratory, Hospital Italiano de Buenos Aires
Capital Federal, Ciudad Autonoma de Buenos Aires, Argentina
DM

Daniela Mezzarobba

MD
Hospital Italiano de Buenos Aires
Buenos Aires, Ciudad Autonoma de Buenos Aires, Argentina
DP

Diana Penchasky

MD
Hospital Italiano de Buenos Aires
Buenos Aires, Ciudad Autonoma de Buenos Aires, Argentina
EV

Estela Viñuales

MD
Hospital Italiano de Buenos Aires
Buenos Aires, Ciudad Autonoma de Buenos Aires, Argentina
JA

Jorge Arbelbide

MD
Hospital Italiano de Buenos Aires
Buenos Aires, Ciudad Autonoma de Buenos Aires, Argentina
MM

Marta Martinuzzo

Biochemist
Central Laboratory, Hospital Italiano de Buenos Aires
Ciudad Autonoma de Buenos Aires, Ciudad Autonoma de Buenos Aires, Argentina

Background: HIT is a life-threatening condition secondary to heparin exposure. Prompt recognition, diagnosis, and alternate anticoagulation are essential. Parenteral non-heparin anticoagulants are unavailable in our country since mid-2017.

Aims: To describe characteristics and treatment of patients with HIT suspicion and positive anti-FP4/heparin antibodies (aFP4/H) and compare patients who received or not appropriate treatment according to international guidelines

Methods: Descriptive retrospective cohort study including all adult patients with positive aFP4/H (HemosIL HIT-Ab, Instrumentation Laboratory), in a high complexity general hospital between 2017-2022.

Results: 43 patients, 52% women, mean age 69 y.o. 4Ts Score: intermediate- or high-probability in 95% of patients. Median (IQR) platelets 51900(40150-64500)/mm3. Surgical admissions in 38%, the most frequent cardiovascular surgery. UFH was given to 35 patients. Thrombotic events: 21 patients, being more frequent lower limb DVT (52%). Patients with thrombotic events had higher 4Ts score (p 0,0001) and a tendency to higher median antibodies title (5,7 vs 3,2 p 0,19)
Two patients continued on heparin treatment, in one HIT diagnosis dismissed and another on ECMO support and intravenous immunoglobulin treatment. In 67% alternative anticoagulants were started: 7 Bivalirudina, 6 Rivaroxaban, 4 Apixaban and 10 dicumarinics.
Two patients receiving Rivaroxaban on hemodialysis (one on ECMO) needed supra-therapeutic doses to achieve optimal drug plasma levels monitored by Rivaroxaban calibrated anti-Xa assay. Only 34% of patients received proper treatment according to ASH 2018 guidelines. Inferior vena cava filter was used in 5 patients, 4 patients received intravenous immunoglobulin. Non-significant differences were found in bleeding and days with thrombocytopenia ( < 150000/mm3) between patients with or without appropriate treatment. Eighteen patients died during follow-up, 72% did not receive appropriate treatment without significant difference.

Conclusion(s): In our experience, the treatment of patients with HIT was difficult due to unavailability of non-heparin parenteral anticoagulants, a situation that may worsen the mortality rate. Guidelines based on local availability are needed.