PLASMA THROMBOMODULIN LEVEL IN VERY-LOW-BIRTH-WEIGHT INFANTS AT BIRTH

Objective: Plasma soluble thrombomodulin level reflects endothelial da mage. The plasma thrombomodulin level at birth is increased in asphyxi ated full-term infants. There is no report of plasma thrombomodulin le vel in premature infants. To determine the thrombomodulin level in pre mature infants and whether it might reflect endothelial damage, we exa mined the plasma thrombomodulin level in very low birthweight (VLBW) i nfants at birth, Methods: Forty-five VLBW infants, of whom 14 had peri natal asphyxia complications, were recruited. As a control, 50 full-te rm infants without complications were also studied. Plasma thrombomodu lin concentration, pH, base deficit, serum creatinine and D-dimer conc entration, platelet count and fibrinogen concentration were measured w ithin 1 hour after birth. Results: There were significant differences in plasma pH, creatinine concentration, platelet count, antithrombin I II activity and D-dimer concentration between VLBW infants and full-te rm infants. Plasma thrombomodulin concentration (39.0 (16.6-93.7) vs 2 7.0 (16.6-39.1) mu g/L, p < 0.0001) and plasma thrombomodulin-to-serum creatinine ratio (0.82 (0.19-2.65) vs 0.47 (0.24-0.70) mu g/mu mol, p < 0.0001) were significantly higher in VLBW infants than those in ful l-term infants. By univariate analyses for all neonates, there were si gnificant relations between plasma thrombomodulin concentration and ge stational age, birthweight, plasma pH, creatinine concentration, plate let count and antithrombin III activity. A stepwise multiple linear re gression model using the above variables as dependent factors showed o nly birthweight contributed significantly to plasma thrombomodulin con centration (plasma thrombomodulin concentration (mu g/l) = 45.677-0.00 6 (birthweight; g), r(2) = 0.323, < 0.0001, n = 94). Plasma thrombomod ulin concentration and plasma thrombomodulin-to -serum creatinine rati o in VLBW infants with asphyxia were higher than in those without asph yxia, but not significantly different (43.2 +/- 17.7 vs 38.3 +/- 8.5 m u g/l and 0.92 +/- 0.60 vs 0.83 +/- 0.37 mu g/mu mol). Conclusion: Pla sma thrombomodulin level in VLBW infants shows a high value at birth, and we consider the main factor responsible for this elevation may be endothelial damage or low clearance rate of thrombomodulin, which may be related to early gestational age.