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Infant cardiopulmonary bypass: a procoagulant state
J J Jaggers1, M C Neal, P K Smith
1Department of Surgery, Duke University Medical Center, Durham, North Carolina 27710, USA. jagge003@mc.duke.edu
Insights
Infants undergoing cardiopulmonary bypass (CPB) show altered coagulation and fibrinolytic systems. Post-CPB serum induces endothelial procoagulant activity, indicating a potential hypercoagulable state in infants after cardiac surgery.
Area of Science:
- Pediatric Cardiology
- Hematology
- Vascular Biology
Background:
- Cardiopulmonary bypass (CPB) in infants may lead to thrombotic and bleeding complications.
- Tissue factor and prothrombinase activity on endothelial cells are key in activating the extrinsic clotting cascade.
Purpose of the Study:
- To characterize the fibrinolytic and endothelial procoagulant state in infants undergoing congenital cardiac repairs.
- To compare these states in infants with and without CPB.
Main Methods:
- 14 infants (1-12 weeks) underwent cardiac repair (2 closed, 12 open).
- Serum samples collected pre- and post-CPB (1, 4, 24 hours).
- Measured tissue plasminogen activator, plasminogen activator inhibitor-1, IL-1beta, IL-6, tissue factor, and factor V. Assayed endothelial cell cultures for tissue factor and prothrombinase activity.
Main Results:
- CPB-treated infants showed transient increases in tissue plasminogen activator and plasminogen activator inhibitor-1.
- Endothelial tissue factor activity was induced post-CPB, with prothrombinase activity remaining elevated.
- Serum factor V levels decreased significantly after CPB but recovered by 24 hours.
Conclusions:
- Cardiopulmonary bypass disrupts coagulation and fibrinolytic systems in infants.
- Post-CPB serum promotes endothelial procoagulant activity.
- A hypercoagulable state may exist in infants during the post-CPB period.
Background:
Procoagulant activity after cardiopulmonary bypass (CPB) in infants may predispose to thrombotic and bleeding complications. The induction of tissue factor and prothrombinase activity on endothelial cell membranes is a primary step in the activation of the extrinsic clotting cascade. The purpose of this study is to characterize the fibrinolytic and endothelial procoagulant state in infants undergoing congenital cardiac repairs with and without CPB.
Methods:
Fourteen infants (aged 1 to 12 weeks) underwent repair of congenital cardiac defects. Two patients had closed procedures (controls) and 12 had open cardiac procedures. Serum samples were taken before and after CPB, 1, 4, and 24 hours after CPB. Tissue plasminogen activator, plasminogen activator inhibitor-1, interleukin-1beta, interleukin-6, plasma tissue factor, and factor V levels were measured. Human umbilical vein endothelial cell cultures were incubated with serum taken from the above time points and assayed for induction of tissue factor and prothrombinase activity.
Results:
Control patients had no change from preoperative values in any of the parameters examined. In experimental patients, tissue plasminogen activator levels peaked at 1 hour after CPB and then decreased to normal by 24 hours. Plasminogen activator inhibitor-1 levels peaked at 4 hours after CPB and returned to baseline by 24 hours. The plasma of all patients had no intrinsic tissue factor activity. Induction of tissue factor activity on umbilical vein endothelial cells peaked immediately and again at 24 hours, whereas prothrombinase activity peaked early and stayed elevated. Serum factor V levels were significantly reduced after CPB, but returned to near baseline levels by 24 hours.
Conclusions:
Cardiopulmonary bypass is associated with derangement of the coagulation and fibrinolytic systems in infants. The serum of these patients promotes the induction of endothelial procoagulant activity, suggesting that there may be a hypercoagulable state in the postbypass period.