Platelet Hyporeactivity in Young Infants During Cardiopulmonary Bypass

Abstract

Platelets of young infants are less reactive than those of children during cardiopulmonary bypass, as determined by the cardiopulmonary bypass-induced alterations in platelet membrane adhesive receptors.

Using reagent-supported thromboelastometry (ROTEM®) to monitor haemostatic changes in congenital heart surgery employing deep hypothermic circulatory arrest

“…As there was no direct correlation between age and Pselectin expression or aggregate formation, an obvious platelet hyporeactivity, as described for young infants [8] was not observed in our patients. Nevertheless, it should be taken into consideration that in our study platelet hyporeactivity contributed to the finding of missing CPB-and hypothermia-associated platelet aggregation.…”

“…The highest amount was observed directly after DHCA with a 2.6-fold increase to geometric mean 5.4% (95% CI: 3.6-8.2%) of P-selectin expressing platelets. With respect to a possible platelet hyporeactivity in young infants [8] platelet P-selectin expression of each patient was compared at the different sampling time points. Directly before DHCA the highest amount of P-selectin expressing platelets (25.2%) was found in the oldest infant and directly after DHCA the highest amount of P-selectin expression (31.5%) was found in the youngest infant, whereas the other patients showed an ageindependent distribution regarding P-selectin expression without a tendency for an increase with older age.…”

“…DHCA may add further damage to haemostasis because in addition to hypothermia it also involves blood stasis. The CPB-and DHCA-related coagulopathy may be especially problematic in neonates and young infants for which reduced platelet reactivity has been reported [8]. Disturbances of haemostasis during cardiac surgery can result in potentially life-threatening complications such as bleeding, as well as fibrin and platelet deposition on the CPB surface and blood clot formation in the CPB circuit [3,9,10].…”

In vitro anti-platelet potency of ticagrelor in blood samples from infants and children

“…Several mechanisms have been suggested to cause or contribute to the hyporesponsiveness including undeveloped intracellular signaling pathways of neonatal platelets. [15] It is unclear how long this hyporeactive phase lasts but some data suggests that the time to normalization is short, 7-14 days [16,17], whereas other studies indicate that it may take months [18] or even years [19] until platelet reactivity is comparable to adults. The results of the present study suggest that ADP-induced P2Y 12 signaling is normalized after two weeks since all children in the youngest group (0-2 months) were >14 days old and the ADP-induced VASP results of this group did not differ compared with the other groups of children, or to the adult group.…”

Blood transfusions in neonatal cardiac surgery and ECMO

“…Platelets of young infants (< 2 months of age) with congenital heart disease are less activated by cardiopulmonary bypass compared with platelets from children older than 12 months. The clinical significance, for instance regarding the trigger for platelet transfusion for the very small infants is unknown [37]. Because platelet number and function are impaired after cardiac surgery, there is concern about volume replacement with solutes affecting platelet function.…”