Abstract 120 Heparin‐induced thrombocytopenia in patients undergoing venoarterial extracorporeal membrane oxygenation

Background: Heparin-induced thrombocytopenia (HIT) is a serious, immune‐mediated adverse drug reaction to unfractionated heparin (UFH) affecting also patients undergoing venoarterial extracorporeal membrane oxygenation (VA-ECMO). Although the association between VA-ECMO support and the development of thrombocytopenia has long been known and discussed, HIT as one underlying cause is still insufficiently understood. Therefore, the purpose of this study was to further investigate the epidemiology, mortality, diagnosis, and clinical management of HIT occurring in VA-ECMO patients treated with UFH.

Methods: We conducted a retrospective single-center study including adult patients (≥18 years) with VA-ECMO support in the cardiac intensive care unit (ICU) of the University Hospital of Munich (LMU) between January 2013 and May 2022, excluding patients with known history of HIT upon admission. Differences in baseline characteristics and clinical outcome between excluded HIT (positive anti-platelet factor 4 (PF4) /heparin antibody test but negative functional assay) and confirmed HIT (positive anti-PF4/heparin antibody test and positive functional assay) VA-ECMO patients as well as diagnosis and clinical management of HIT were analysed.

Results: Among 373 patients included, anti-PF4/heparin antibodies were detected in 53/373 (14.2%) patients. Functional HIT testing confirmed HIT in 13 cases (3.5%) and excluded HIT in 40 cases (10.7%), corresponding to a prevalence of confirmed HIT of 13/373 (3.5%) [1.6, 5.3] and a positive predictive value (PPV) of 24.5% for the antibody screening test. 1-month mortality in patients with excluded HIT was 14/40 (35%) and 3-month mortality 17/40 (43%), compared to 5/13 (38%) (p>0.999) and 6/13 (46%) (p>0.999) in patients with confirmed HIT. Neurological outcome in both groups measured by cerebral performance category of survivors on hospital discharge was similar as well as adverse events during VA-ECMO therapy. The platelet course including platelet recovery following argatroban initiation was similar between all groups.

Conclusion: With a prevalence of 3.5%, HIT is a non-frequent complication in patients on VA-ECMO and was not associated with a higher mortality rate. HIT was ultimately excluded by functional essay in 75% of VA-ECMO patients with clinical suspicion of HIT and positive anti-PF4/heparin antibody test. Additionally, argatroban seems to be an appropriate and safe therapeutic option for confirmed HIT-positive patients on VA-ECMO support.

Clin Res Cardiol (2023). https://doi.org/10.1007/s00392-023-02180-w
Heparin‐induced thrombocytopenia in patients undergoing venoarterial extracorporeal membrane oxygenation
E. Lüsebrink¹, C. Scherer², L. Binzenhöfer³, S. Hoffmann⁴, J. Höpler⁴, A. M. Kellnar¹, M. Thienel¹, D. Joskowiak⁵, S. Peterß⁵, T. Petzold¹, S. Deseive¹, R. Hein-Rothweiler¹, S. Brunner¹, S. Kääb¹, D. Braun¹, H. D. Theiss¹, J. Hausleiter¹, C. Hagl⁵, S. Massberg¹, M. Orban¹
¹Medizinische Klinik und Poliklinik I, LMU Klinikum der Universität München, München; ²Klinikum rechts der Isar der Technischen Universität München, München; ³Kardiologie, LMU Klinikum Großhadern, München; ⁴Institut für Medizinische Informationsverarbeitung Biometrie und Epidemiologie, München; ⁵Herzchirurgische Klinik und Poliklinik, LMU Klinikum der Universität München, München;
Background: Heparin-induced thrombocytopenia (HIT) is a serious, immune‐mediated adverse drug reaction to unfractionated heparin (UFH) affecting also patients undergoing venoarterial extracorporeal membrane oxygenation (VA-ECMO). Although the association between VA-ECMO support and the development of thrombocytopenia has long been known and discussed, HIT as one underlying cause is still insufficiently understood. Therefore, the purpose of this study was to further investigate the epidemiology, mortality, diagnosis, and clinical management of HIT occurring in VA-ECMO patients treated with UFH. Methods: We conducted a retrospective single-center study including adult patients (≥18 years) with VA-ECMO support in the cardiac intensive care unit (ICU) of the University Hospital of Munich (LMU) between January 2013 and May 2022, excluding patients with known history of HIT upon admission. Differences in baseline characteristics and clinical outcome between excluded HIT (positive anti-platelet factor 4 (PF4) /heparin antibody test but negative functional assay) and confirmed HIT (positive anti-PF4/heparin antibody test and positive functional assay) VA-ECMO patients as well as diagnosis and clinical management of HIT were analysed. Results: Among 373 patients included, anti-PF4/heparin antibodies were detected in 53/373 (14.2%) patients. Functional HIT testing confirmed HIT in 13 cases (3.5%) and excluded HIT in 40 cases (10.7%), corresponding to a prevalence of confirmed HIT of 13/373 (3.5%) [1.6, 5.3] and a positive predictive value (PPV) of 24.5% for the antibody screening test. 1-month mortality in patients with excluded HIT was 14/40 (35%) and 3-month mortality 17/40 (43%), compared to 5/13 (38%) (p>0.999) and 6/13 (46%) (p>0.999) in patients with confirmed HIT. Neurological outcome in both groups measured by cerebral performance category of survivors on hospital discharge was similar as well as adverse events during VA-ECMO therapy. The platelet course including platelet recovery following argatroban initiation was similar between all groups. Conclusion: With a prevalence of 3.5%, HIT is a non-frequent complication in patients on VA-ECMO and was not associated with a higher mortality rate. HIT was ultimately excluded by functional essay in 75% of VA-ECMO patients with clinical suspicion of HIT and positive anti-PF4/heparin antibody test. Additionally, argatroban seems to be an appropriate and safe therapeutic option for confirmed HIT-positive patients on VA-ECMO support.
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