The role of von Willebrand factor in haemostasis and blood loss during and after cardiopulmonary bypass surgery.
Excessive perioperative and postoperative bleeding continue to complicate cardiopulmonary bypass surgery (CPB). In this study we measured the von Willebrand factor antigen (vWF:Ag), collagen binding assay (CBA) and ristocetin cofactor assay (RiCo) in 52 patients undergoing CPB. The collagen binding assay employs the affinity of the high-molecular-weight multimers of vWF to collagen and was used in this study to demonstrate differences in the multimeric composition of vWF during and after CPB. The observed values for the vWF:Ag, CBA and RiCo were correlated to the amount of postoperative bleeding. Both the preoperative vWF:Ag and the CBA showed significant negative correlation with postoperative blood loss (r = -0.3046, P < 0.05 and r = -0.3228, P < 0.05 respectively). Higher blood loss figures correlated with lower vWF:Ag, CBA and RiCo during and after surgery with the strongest correlation 1 h post-op between both vWF:Ag and CBA and actual blood loss (r = -0.5061, P < 0.001 and r = -0.4942, P < 0.001 respectively). The strong negative correlations between vWF:Ag, CBA and RiCo before, during and after CPB and blood loss data verify the important role of vWF in primary haemostasis. Of particular note, the negative correlations between preoperative levels of vWF:Ag, CBA and postoperative blood loss provide valuable insight into another possible mechanism of excessive bleeding post CPB.
Perrin
E J
EJ
Division of Haematology, Prince Charles Hospital, Brisbane, Queensland, Australia.
Ray
M J
MJ
Hawson
G A
GA
D000017:ABO Blood-Group System; D000375:Aging; D000941:Antigens / Q000032:analysis; D001760:Bleeding Time; D016063:Blood Loss, Surgical; D002315:Cardiopulmonary Bypass / Q000009:adverse effects*; D003094:Collagen / Q000378:metabolism; D005260:Female; D006438:Hemodilution; D006801:Humans; D008297:Male; D011183:Postoperative Complications; D012727:Sex Characteristics; D014841:von Willebrand Factor / Q000032:analysis / Q000502:physiology*
D000017:ABO Blood-Group System; D000941:Antigens; C029417:Von Willebrand antigen; D014841:von Willebrand Factor; D003094:Collagen