Abstract
Cardiopulmonary bypass (CPB) is asociated with haemostatic disturbances and signs
of acute inflammatory response, most likely related to poor biocompatibility of the
artificial surfaces. Some haemostatic variables are known as markers of acute-phase
reaction, blood cell trauma, and endothelial damage. The aim of the study was to evaluate
the effect of heparincoating of artificial surfaces on those variables of hemostasis.
14 patients operated on with elective coronary artery revascularization were randomized
into two groups. In group H (n = 7), heparin-coated CPB circuits and in control group
C (n = 7), noncoated CPB sets were used. Patients in group C received normal heparinization,
e.g. bolus 300 IU/kg and additional doses to maintain activated coagulation time (ACT)
over 400 sec during CPB. In group H, a bolus heparin dose was reduced by 25% (to 225
IU/kg) in order to compensate for the amount of heparin immobilized on circuit surfaces
and the corresponding ACT limit was 300 sec. There were significant increases of the
von Willebrand factor (vWf), Plasminogen activator inhibitor-1 (PAI) and tissue-plasminogen
activator (tPA) starting at CPB end and rising to about twice the baseline levels
postoperatively. This reaction was less evident in group H, as indicated by significantly
lower levels of tPA compared to group Cat CPB end (135% ± 9 in group H versus 241
% ± 15 in group C, p < 0.0005) and at two hours postoperatively. The rates of tPA
and vWF increase were lower in group H, also indicating reduced endothelial damage
in this group. Marginally significant, a higher value of PAI was found in the C group
early after CPB onset. Group H showed significantly lower concentrations of circulating
complex between elastase and alpha1-antitrypsin at CPB end and postoperatively, implicating
a reduced granulocyte activation (60 min after protaminization 41 μg/L ± 5 in group
H versus 256μg/L ± 55 in group C, p <0.05). It was concluded that the heparin-coated
CPB circuits demonstrated improved biocompatibility which may be related to less disturbed
haemostasis.
Key words
Cardiopulmonary bypass - Heparin-coating - Biocompatibility
