Role of factor XII in thrombin generation and fibrinolysis during cardiopulmonary bypass.
During cardiopulmonary bypass, thrombin is generated, which is thought to be initiated by activation of factor XII on the surface of the bypass equipment. We present a patient with severe factor XII deficiency who underwent cardiac surgery. As much thrombin was formed during cardiopulmonary bypass (measured by the prothrombin activation fragment F1 + 2 and thrombin-antithrombin complexes) as in normal patients, showing that factor XII was not necessary for thrombin generation. Factor X, but not factor IX, was activated (as measured by their activation peptides), and this activation correlated with F1 + 2 and thrombin-antithrombin complexes, suggesting that the tissue-factor/factor-VIIa pathway is the trigger for thrombin formation.
Burman
J F
JF
Department of Haematology, Royal Brompton Hospital, London, UK.
Chung
H I
HI
Lane
D A
DA
Philippou
H
H
Adami
A
A
Lincoln
J C
JC
D000990:Antithrombin III / Q000032:analysis; D002315:Cardiopulmonary Bypass; D002648:Child; D004374:Ductus Arteriosus, Patent / Q000601:surgery; D005174:Factor XII / Q000502:physiology*; D005175:Factor XII Deficiency / Q000097:blood / Q000150:complications; D005260:Female; D005342:Fibrinolysis; D006343:Heart Septal Defects / Q000601:surgery; D006801:Humans; D010446:Peptide Fragments / Q000032:analysis; D010447:Peptide Hydrolases / Q000032:analysis; D011516:Prothrombin / Q000032:analysis; D013917:Thrombin / Q000378:metabolism*
D010446:Peptide Fragments; C046193:antithrombin III-protease complex; C045879:prothrombin fragment 1.2; D000990:Antithrombin III; D011516:Prothrombin; D005174:Factor XII; D010447:Peptide Hydrolases; D013917:Thrombin