TEG® 6s heparin neutralization cartridge for hemostatic assessment of patients undergoing cardiovascular surgery

Background: Heparin administration can limit viscoelastic testing. The cartridge-based TEG ® 6s thromboelastography system uses heparinase to neutralize heparin effects. This study aimed to validate the TEG ® 6s Global Hemostasis – Heparin Neutralization cartridge, recently cleared by the U.S. Food and Drug Administration, in heparinized patients undergoing cardiovascular surgery with cardiopulmonary bypass or cardiovascular procedures without cardiopulmonary bypass. Methods: Adult patients undergoing cardiovascular surgery/invasive cardiac procedures with planned use of unfractionated heparin were included in this multicenter observational study. Blood samples were obtained before heparin administration, after heparin administration, and after heparin reversal (or end of the procedure when protamine was not administered). The kaolin, and kaolin with heparinase assays on the Heparin Neutralization cartridge were compared with their identical counterparts on the clinically validated TEG ® 6s Citrated Multichannel cartridge; The RapidTEG TM with heparinase assay was evaluated against the kaolin with heparinase assay on the Citrated Multichannel cartridge. The functional fibrinogen with heparinase assay was evaluated against plasma fibrinogen levels measured (Clauss assay). Comparison analysis was performed using Deming linear regression or Pearson/Spearman correlation. Results: A total of 543 samples were collected from 185 patients (113 cardiovascular surgery with cardiopulmonary bypass; 72 cardiovascular procedures without cardiopulmonary bypass). Deming regression slopes were equal to/approximately 1.0 for comparisons between assays on the Heparin Neutralization and Citrated Multichannel cartridges; Pearson correlation coefficients ranged from 0.79–0.96. The functional fibrinogen with heparinase assay was correlated with plasma fibrinogen levels (Spearman correlation: 0.68). Addition of heparinase to the RapidTEG TM and functional fibrinogen assays resulted in a higher number of analyzable samples compared to these assays without heparinase. Conclusions: This study provided clinical validation for the TEG ® 6s Heparin Neutralization cartridge for point-of-care coagulation testing in patients undergoing cardiovascular surgeries or procedures. Further prospective trials with clinical endpoints are needed to determine the clinical utility of this cartridge.