Platelet factor-4 concentration in adult veno-arterial ECMO patients. (October 2021)

• Record Type: Journal Article
• Authors: Mazzeffi, Michael; Clark, Madeline; Grazioli, Alison; Dugan, Colleen; Rector, Raymond; Dalton, Heidi; Madathil, Ronson; Menaker, Jay; Herr, Daniel; Tanaka, Kenichi
• Is Part Of: Perfusion. Volume 36:Number 7(2021)
• Page Start: 688
• Page End: 693
• Publication Date: 2021-10
• Subjects: ECMO -- HIT -- thrombosis -- platelet factor-4 -- heparin; Perfusion (Physiology) -- Periodicals; Blood -- Circulation, Artificial -- Periodicals; Heart -- Surgery -- Periodicals; Extracorporeal Circulation -- Periodicals; Perfusion -- Periodicals; Circulation extracorporelle -- Périodiques; Perfusion -- Périodiques; 617.41
• DOI: 10.1177/0267659120965104
• Languages: English
• ISSNs: 0267-6591

Abstract

Background: Heparin induced thrombocytopenia (HIT) is reported at a variable rate in extracorporeal membrane oxygenation (ECMO) patients. A critical factor impacting platelet factor-4 (PF4)-heparin antibody formation is plasma PF4 concentration. We hypothesized that PF4 concentration would be increased during veno-arterial (VA) ECMO. Methods: Plasma PF4 concentration was measured during the first 5 ECMO days in 20 VA ECMO patients and 10 control plasma samples. PF4-heparin ratios were estimated using an assumed heparin concentration of 0.4 IU/mL. This correlates with an activated partial thromboplastin time of 60 to 80 seconds, which is the anticoagulation target in our center. Results: Twenty VA ECMO patients were enrolled, 10 of which had pulmonary embolism. Median PF4 concentration was 0.03 µg/mL [0.01, 0.13] in control plasma. Median PF4 concentration was 0.21 µg/mL [0.12, 0.34] on ECMO day 1 or 2, 0.16 µg/mL [0.09, 0.25] on ECMO day 3, and 0.12 µg/mL [0.09, 0.22] on ECMO day 5. Estimated median PF4-heparin ratios were 0.04, 0.03, and 0.02 respectively. Two patients (10%) developed HIT that was confirmed by serotonin release assay. PF4 concentration did not differ significantly in these patients compared to non-HIT patients (p = 0.37). No patient had an estimated PF4-heparin ratio between 0.7 and 1.4, which is the reported optimal range for PF4-heparin antibody formation. Conclusion: Our data suggest that PF4 concentration is mildly elevated during VA ECMO compared to control plasma. Estimated PF4-heparin ratios were not optimal for HIT antibody formation. These data support epidemiologic studies where HIT incidence is low during VA ECMO.