Heart Lung

Background: Mechanical circulatory support (MCS) systems assist patients with severe cardiac or respiratory failure, but bleeding linked to acquired von Willebrand disease remains a major complication. The T-TAS® 01 system has emerged as a rapid tool for assessing MCS patients' hemostasis.

Objectives: To evaluate hemostatic changes during and after MCS support. Secondary objectives included assessing the impact of the in vitro addition of von Willebrand factor concentrates and exploring differences according to the presence of a membrane oxygenator (MO).

Methods: This prospective, bicentric study included adults requiring MCS, with hemostatic parameters assessed at three predefined timepoints using conventional laboratory assays and T-TAS® 01. Data were analyzed using linear mixed-effects models. In vitro addition of a VWF/FVIII concentrate (Haemate-P®) was evaluated as an exploratory analysis.

Results: A total of 39 patients were included; 56% experienced bleeding complications, of which 23% were clinically relevant. Significant alterations in hemoglobin, platelet counts, and platelet/VWF function were observed during MCS. T-TAS® 01 demonstrated impaired hemostasis during support, with partial recovery after device removal. In vitro addition of Haemate-P® improved T-TAS® 01 parameters. No consistent differences in overall hemostatic dynamics were observed between MO and non-MO devices.

Conclusion: MCS is associated with significant and persistent alterations in primary hemostasis. T-TAS® 01 may represent a useful tool for dynamic assessment of these changes. In vitro VWF supplementation improved functional hemostasis parameters, although its clinical implications remain to be established. Differences related to MO presence were not consistent, supporting a shared mechanism of hemostatic dysregulation across MCS devices.