PLASMA THROMBOMODULIN CONCENTRATIONS IN INFANTS AND CHILDREN UNDERGOING CARDIAC-CATHETERIZATION

Circulating plasma thrombomodulin (TM) is an endothelial cell marker w hich may reflect endothelial injury. To find out to what extent diagno stic cardiac catheterization irritates vascular endothelium we conduct ed a prospective study in 91 children. Soluble TM concentrations, alon g with thrombin generation, were measured before, at the end of and 24 hours after cardiac catheterization. Compared to starting values, TM concentrations showed a clearly significant increase at the end of car diac catheterization and returned to pretreatment values 24 hours late r. Thrombin generation followed a similar pattern. Five out of the 91 children demonstrated resistance to activated protein C (APCR). With r espect to the remaining 86 children, all five APCR cases showed increa sed thrombomodulin concentrations along with enhanced thrombin generat ion. Data from this study indicate that increased TM concentrations af ter cardiac catheterization in children are a sign of short-term endot helial damage. Furthermore, together with enhanced thrombin generation , elevated plasma concentration of soluble TM may reflect this recepto r's possible anticoagulant properties.