Heparin causes platelet dysfunction and induces fibrinolysis before cardiopulmonary bypass.
BACKGROUND
Platelet dysfunction and increased fibrinolysis are the most important etiologic factors in the hemostatic defect observed following the institution of cardiopulmonary bypass. This study examined the effects of heparin per se, administered before the institution of cardiopulmonary bypass, on platelet function and fibrinolysis.


METHODS
Sampling was performed in 55 patients undergoing cardiac operations before and 5 minutes after the routine administration of heparin, before the institution of cardiopulmonary bypass.


RESULTS
Heparin administration resulted in a significant prolongation of the bleeding time (from 6.3 +/- 2.1 to 12.6 +/- 4.9 minutes; p < 0.00001), a significant reduction in the level of shed blood thromboxane B2 (from 1,152 +/- 669 to 538 +/- 187 pg/0.1 mL; p = 0.00002), and an increase in the plasma levels of plasmin (from 11.8 +/- 9.7 to 125.4 +/- 34.8 U/L; p < 0.0001) and D-dimer (from 571.3 +/- 297.1 to 698.5 +/- 358.6 micrograms/mL; p = 0.05). There were no significant differences before and after heparin administration in the plasma levels of fibrinogen, plasminogen, tissue plasminogen activator, antiplasmin, antithrombin III, and von Willebrand factor.


CONCLUSIONS
Heparin, independent of cardiopulmonary bypass, causes both platelet dysfunction and increased fibrinolysis. The use of an alternative anticoagulant or a lower dose of heparin in conjunction with heparin-coated surfaces might improve the hemostatic balance during open heart operations.
Khuri
S F
SF
Department of Surgery, Brockton/West Roxbury Veterans Affairs Medical Center, Massachusetts, USA.
Valeri
C R
CR
Loscalzo
J
J
Weinstein
M J
MJ
Birjiniuk
V
V
Healey
N A
NA
MacGregor
H
H
Doursounian
M
M
Zolkewitz
M A
MA
D000368:Aged; D000925:Anticoagulants / Q000009:adverse effects*; D001780:Blood Coagulation Tests; D001792:Blood Platelets / Q000187:drug effects*; D002315:Cardiopulmonary Bypass; D005260:Female; D005342:Fibrinolysis / Q000187:drug effects*; D006487:Hemostasis / Q000187:drug effects; D006493:Heparin / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011300:Preoperative Care
D000925:Anticoagulants; D006493:Heparin