Dynamics of Platelet Activation in Patients With Ventricular Assist Device (VAD)

The study is aimed at evaluating the patients' haemostatic and coagulation profile focusing, in particular, on platelet function. Platelet function will be analyzed utilizing two innovative analytic diagnostic tests, namely i) the Platelet Activity State (PAS) assay and ii) the Thrombin Generation Test (TGT).

PAS values and TGT will be measured at different time-points over the course of support:

i) before the implant of the support system, to define baseline patients' characteristics; ii) in the early-post implant, during patient hospitalization; iii) during long-term follow up, to evaluate the dynamics of platelet function over the course of support and potential alterations of platelet-mediated haemostatic processes; iv) at the occurrence of any thromboembolic/hemorrhagic complication or following a modification of the antithrombotic pharmacological therapy.

Platelet function will be evaluated through:

i) the Platelet Activity State (PAS) assay, a biochemical assay able to quantify the platelet thrombin production rate and to correlate this rate with the actual level of platelet activation (i.e., the platelet pro-thrombotic tendency); ii) the Thrombin Generation Test (TGT), a biochemical assay that the investigators have properly modified to account selectively for the platelet contribution on plasmatic thrombin generation.

PAS and TGT experimental values will be correlated with the occurrences of post-implant complications. Experimental values will be also correlated with standard clinical parameters of coagulation and hemolysis, such as: platelet count, hematocrit, hemoglobin, prothrombin time (PT), activated partial thromboplastin time (aPTT), International Normalized Ratio (INR), D-Dimer, Fibrinogen, L-lactate dehydrogenase, haptoglobin, plasma-free hemoglobin, and C-reactive protein levels. Also levels of thrombin-antithrombin complex, Von Willebrand factor, prothrombin1,2 fraction and tissue factor, will be measured and recorded. In addition, pump (i.e. VAD) working parameters (i.e., rotation velocity, cardiac outflow and power consumption) will be recorded. Log-files of the pump will be downloaded and analyzed to characterize the correlation with the development of adverse events (AV). Finally, antithrombotic therapy will be recorded and used in the study.

Inclusion criteria

• All consenting patients candidates for short-term (Impella, ECMO) or durable (LVAD) mechanical circulatory support device implantation
• All consenting patients that are implanted with short-term (Impella, ECMO) or durable (LVAD) mechanical circulatory support device

Exclusion criteria

• Patients < 18-years old