Treatment of the coagulation deficit during extracorporeal circulation in a porcine model by a prothrombin complex concentrate

Introduction

Many procedures in cardiac surgery require extracorporeal circulation (EC). During EC, blood is pumped from a venous line to an oxygenator, cooled and infused back via an arterial line. This procedure is known to compromise the coagulation system, especially under prolonged hypothermia. The aim of the present study was to investigate the effects of EC and hypothermia on the coagulation system in a porcine model. The efficacy of a substitution therapy with a prothrombin complex concentrate (PCC) regarding normalization of coagulation and decrease in hemorrhage was evaluated.

Methods

A total of 17 male anesthetized pigs were included in the study. EC was performed in 12 animals by a hollowfiber oxygenator with a priming solution containing saline, HES and heparin. Five animals without EC served as a control. The coagulation system was characterized by thromboelastography (TEG), thrombin generation, coagulation factor levels, platelet numbers and function (aggregation). A GoreTex patch was inserted into the carotid artery, bleeding occurred from the stitch channels. The effects of intravenous substitution therapy by PCC (Beriplex P/N, 30 U/kg, n = 6) compared with placebo (n = 6) on bleeding from the stitch channels was investigated.

Results

EC and hypothermia compromised the coagulation system. Coagulation factor levels were decreased, TEG and thrombin generation became pathologic. Platelet count and aggregation were decreased. Blood loss from the stitch channels of the GoreTex patch was doubled in the EC group when compared with animals without EC. After substitution therapy with PCC, blood loss decreased significantly from 83.0 ± 48.4 ml in the EC + placebo to 27.2 ± 35 ml in the EC + PCC group (P < 0.025, Wilcoxon test; Figure 1). PCC normalized the impaired coagulation.

Figure 1

Blood loss from a GoreTex Patch after EC.

Conclusions

Hypothermia and EC led to a compromised coagulation system, resulting in increased hemorrhage. The deficit in coagulation could be overcome by substitution therapy with PCC. Elevated blood loss from stitch channels was decreased significantly after treatment with PCC. It was concluded that PCC should be beneficial in patients undergoing cardiovascular surgery with an EC-induced coagulopathy.