Introduction Platelet dysfunction (thrombocytopathy) is a major problem in the bleeding patient and increases morbidity and healthcare costs. The thrombocytopathy resulting from cardiopulmonary bypass (CPB) can be used to study therapies targeted to improve outcomes in other scenarios, such as trauma. Platelet transfusion is used widely to correct thrombocytopathy. However, the current standard, room temperature stored platelets (RTP) have several disadvantages including; short shelf life, risk of bacterial contamination and deterioration in platelet function during storage. Cold stored platelets (CSP) are a potential alternative product with longer shelf life, reduced contamination risk and better-preserved platelet function.

Methods Using ex vivo mixing studies, we investigated whether CSP were better able to reverse the thrombocytopathy associated with cardiac surgery than RTP. Blood samples were collected from 20 cardiac surgery patients. Donor platelets were split into two bags and stored at either 4°C (CSP), or 22°C (RTP) for up to seven days. The donor platelets were mixed with the patient blood samples to simulate platelet transfusion. The mixed samples were analysed using the TEG 5000 and using a collagen coated flow chamber at arterial shear. Patient samples were analysed alongside healthy controls (n = 20).

Results After mixing the patient samples with CSP, the TEG R times were shorter than in samples mixed with RTP (p<0.0001), indicating more rapid initiation of clot formation. In the flow chamber experiments, the clot volume was greater in the patient samples mixed with CSP compared with samples mixed with RTP (p<0.0001).

Conclusions These findings suggest that CSP, but not RTP can partially reverse the thrombocytopathy associated with cardiac surgery ex vivo, at clinically relevant mixing volumes. Reversal of thrombocytopathy by mixing CSP was greatest in the arterial shear model, which may indicate superior in vivo efficacy that requires confirmation in clinical trials.

* this abstract presentation was awarded First Place.