Heparin management and hemostatic risk evaluation in patients undergoing pulmonary thrombo-endarterectomy

Incomplete resolution of pulmonary embolism (PE) can result in a condition
known as chronic thromboembolic pulmonary hypertension (CTEPH), which is
characterized by increased pulmonary vascular resistance, pulmonary
hypertension and eventually right heart failure. The surgical intervention for
CTEPH is called pulmonary thrombo- endarterectomy (PTE) or pulmonary
endarterectomy (PEA), a procedure that requires cardiopulmonary bypass (CPB)
and deep hypothermic circulatory arrest (DHCA). To prevent thrombin generation
from occurring, the anticoagulant heparin is administered to the patient prior
and during CPB and the activated clotting time (ACT) is used to monitor
anticoagulation. However, the ACT may be artificially prolonged during CPB
because of hemodilution and hypothermia and it is unknown whether DHCA during
PTE procedures may result in inadequate heparinization and consequently
hemostatic activation. Since the majority of CTEPH patients show an altered
hemostatic profile, this might increase their risk for thrombotic and/or
bleeding complications.

To provide evidence demonstrating that ACT-guided heparin management during
pulmonary thrombo-endarterectomy (PTE) involving cardiopulmonary bypass (CPB)
and deep hypothermic circulatory arrest (DHCA) will result in inadequate
heparinization and consequently an increase in hemostatic activation.

Single-center, prospective observational study in the VU University Medical
Center.

A total of 105 ml of extra blood will be drawn from an existing intra-arterial
line while the patient is under anesthesia. The intra-arterial line is part of
routine clinical care in cardiac surgery, and will therefore not add up to
patient discomfort in the present study.