Clinical Trial Details
— Status: Not yet recruiting
Administrative data
NCT number |
NCT06050993 |
Other study ID # |
APHP230249 |
Secondary ID |
2023 -A00064-41 |
Status |
Not yet recruiting |
Phase |
|
First received |
|
Last updated |
|
Start date |
October 15, 2023 |
Est. completion date |
April 15, 2024 |
Study information
Verified date |
July 2023 |
Source |
Assistance Publique - Hôpitaux de Paris |
Contact |
n/a |
Is FDA regulated |
No |
Health authority |
|
Study type |
Observational
|
Clinical Trial Summary
Haemostasis of cirrhotic patients is disturbed at different levels: primary haemostasis,
coagulation and fibrinolysis, leading to a new haemostatic balance. Thrombocytopenia and
thrombopathy are counterbalanced by elevation of Von Willebrand factor (VWF) and diminution
of ADAMTS13 activity. Exploration of primary haemostasis is difficult in the laboratory, and
non-interpretable in case of thrombocytopenia. Moreover, these tests are not performed under
flow conditions. The T-TAS®01 system analyses the total haemostatic capacity in whole blood
under shear stress, with chips coated with type 1 collagen. Platelets transfusion performs
poorly in cirrhotic patients and is not recommended before invasive procedure. Platelets
mimicking nanoparticles (PMNs) have been developed by Pr Sen Gupta (Case Western Reserve
University, Cleveland, Ohio (OH), USA). PMNs have been proven to collaborate with platelets
and enhance haemostasis in different shear conditions in vitro and in different models of
haemorrhage in vivo. The assumption of this study is that the perfusions characteristics of
cirrhotic patients in the T-TAS®01 system will be different from those of non-cirrhotic
patients, and that platelets mimicking nanoparticles will improve these characteristics.
Description:
Hepatic cirrhosis is accompanied by an alteration of the haemostatic balance (primary
haemostasis, coagulation, fibrinolysis). With regard to primary haemostasis, thrombocytopenia
is usually moderate, due to splenic or hepatic sequestration associated with portal
hypertension. Platelet synthesis is also reduced. There are also autoimmune thrombocytopenia
due to the presence of anti-platelet autoantibodies. In addition, there is a thrombopathy
with functional alterations in platelet adhesion and aggregation. In parallel with these
abnormalities in platelet adhesion and aggregation, the quantitative increase in the level of
Von Willebrand factor (VWF) preserves the capacity for platelet aggregation, even under
conditions of circulating flow, despite the reduction in the intrinsic functional capacity of
VWF. This increase can be explained by increased hepatic synthesis, a larger endothelial
surface area in the presence of collateral circulation and repeated endothelial aggression by
endotoximia during infections, as well as a decrease in clearance due to a decrease in the
synthesis of ADAMTS13.
Routine investigation of abnormalities in primary haemostasis is based almost exclusively on
platelet counts, as well as plasma VWF and ADAMTS13 assays. Functional platelet tests (PFA®,
impedance aggregometry, light transmission aggregation) are more difficult to perform,
particularly in the case of thrombocytopenia, and are not performed under circulating flow
conditions. The Total Thrombus Formation Analysis System (T-TAS®01) allows analysis of
haemostatic capacity in whole blood and flow conditions. Whole blood is deposited in a
reservoir and then perfused onto a type I collagen-coated chip (PL chip) at a shear rate of
1500 s-1, mimicking blood flow in small arteries. As the clot forms, the pressure in the
perfusion chamber increases until total occlusion occurs. The parameters measured are :
- the time required to achieve a pressure within the perfusion chamber equal to 10
kilopascal (kPa) above the baseline pressure,
- the time required to reach a pressure of 60 kPa above the base pressure in the infusion
chamber (occlusion time)
- the area under the curve at 10 min. The perioperative management of cirrhotic patients
leads the clinician to ask the question of prophylactic platelet transfusion in the
event of thrombocytopenia of less than 30 to 50 G/L. While this threshold value is based
on a low level of evidence, platelet transfusion has a poor performance in cirrhotic
patients and is not without side effects. Thus, preventive platelet transfusion is not
recommended. In the event of bleeding, management should consist of platelet
transfusion, combined with fibrinogen and antifibrinolytic administration. Synthetic
platelet mimicking particles (SPs) are made of a liposomal membrane, and "decorated"
with 3 different peptides: collagen binding peptide (CBP), which binds to fibrillar
collagen exposed at the subendothelium, fibrinogen mimetic peptide (FMP), which can bind
to the active form of platelet integrin αIIbβ3, and VWF binding peptide (VBP), which is
derived from the C2 domain of factor VIII and can bind to the D'-D3 domain of VWF.
Ex vivo, in the absence of endothelial injury, these SPs do not induce platelet aggregation
in the absence of agonist but enhance aggregation in the presence of agonist. These SPs do
not trigger thrombin formation on their own but in the presence of tissue factor SPs increase
thrombin generation and fibrin formation. In perfusion chambers, these nanoparticles allow
platelets to adhere to a collagen-coated surface and to aggregate with each other. In vivo,
SPs collaborate with platelets to restore effective haemostasis in thrombocytopenic mice
undergoing tail-clipping. Their haemostatic efficacy has also been demonstrated in various
animal models of traumatic injury, including a mouse model of liver laceration, a porcine
model of traumatic arterial haemorrhage, and a rodent model of liver resection.
The assumption of this study is that the characteristics of infusions with the T-TAS®01
system will be altered in cirrhotic patients, reflecting impairment of primary haemostasis,
compared to control patients and that platelet-mimicking nanoparticles (PMNs) will correct
these alterations.