Cardiopulmonary Bypass Induces Significant Platelet Activation in Children Undergoing Open-Heart Surgery

Background: To evaluate the effects of cardiopulmonary bypass (CPB) on platelet function in children undergoing open-heart surgery.

Methods: Data from 16 consecutive children undergoing cardiac surgery with CPB were prospectively collected. Blood samples of 10 mL were collected via the central venous line immediately before and after CPB for CD62 measurements by flow cytometry.

Results: Ten children had acyanotic heart disease (median age 3 yr, range 1.8-14) and six had a cyanotic defect (median age 4yr, range 2-14). The platelet count decreased significantly with CPB in both groups: from 163.5 (130-201) to 93.5 (57-186) x 10(3) microL(-1) in acyanotic children and from 139.5 (77-212) to 75 (43-99) x 10(3) microL(-1) in cyanotic children (P < 0.0001). The percentage of activated platelets was significantly lower in acyanotic children at baseline: 1% (0-23%) vs. 5% (3-8%) (P = 0.07). CPB increased the percentage of activated platelets significantly in both groups: post-bypass the values were 10% (range 1-17%) in acyanotic children and 7% (range 1-30%) in cyanotic children (P = 0.03). The increase in the percentage of activated platelets did not differ between the two study groups (P = 0.11).

Conculsions: CPB induces significant platelet activation in children undergoing open-heart surgery.