Excessive blood loss secondary to cardiopulmonary bypass(CPB) may be encountered after open heart surgery and platelet dysfunction appears to be especially responsible for this problem.
To evaluate the effect of low-dose aprotinin during hypothermic CPB on platelet aggregation, anticoagulation and clinical hemostasis 40 patients undergoing valve replacement using hypothermic CPB procedures were randomized to give either a low
dose
aprotinin(2×106 KIU in the CPB priming solution, n=20) or a placebo(n=20).
During postoperative 24 hours, blood and hemoglobin loss were lower in the aprotinin group(225.5±121.9ml, and 11.3±2.4g) than the control group(572.2±335.5ml and 26.3±9.8g).(p<0.01). The total blood and hemoglobin loss were lower in the
aprotinin
group(622.0±186ml and 14.7±6.8g) than the control group(102.1±483.5ml and 39.7±16.4g)(p<0.01). The amonut of packed red cell needed decreased in the aprotinin group: 197.7±56.3ml versus 651.2±147.5ml(p<0.01). Hemoglobin concentration,
platelet
counts and fibrinogen checked at timed times perioperatively did not differ between the two groups. Platelet aggregation was induced by ADP, collagen, epinephrine and ristocetin before and after CPB. Maximum platelet aggregation was significantly
reduced after CPB in control group (ranging from -31% to 58% relative to prebypass values). Significant prolongation of activated clotting time(ACT) after 5 minute and 30 minute of hypothermic CPB were observed: 955.9±35.1 and 961.5±32.7sec
versus
743.8±52.1 and 731.2±54.6sec(p<0.01). There was no complication associated with aprotinin infusion.
These results demonstrate that low-dose aprotinin significantly reduces blood loss and blood requirment and provides improved postoperative hemostasis which might be related to protection of platelet aggregation capacity.
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