RESULTS AND DISCUSSION
In 95 pediatric patients undergoing CCVR for craniosynostosis, 47
patients received EACA and 48 patients received TXA. There were no
differences in demographics, procedure category, operative time, or CBL
between antifibrinolytic groups (Supplemental Table
1).24 Perioperative hematologic and coagulation
laboratory values were reviewed and the minimum or maximum value for
each was recorded (Table 1). Preoperative laboratory values were within
normal range on all patients and there were no differences between
antifibrinolytic cohorts. Postoperative laboratory parameters are
depicted in spaghetti plots in Supplemental Figure 1. Intraoperative
hematocrit fell as expected with appreciated BL and did not fully
recover for most patients, despite RBC transfusion intraoperatively in
59 patients (62%) and postoperatively in 22 patients (23%). No
patients developed significant thrombocytopenia perioperatively.
Hypofibrinogenemia was not seen and fibrinogen activity tended to
increase postoperatively. PT and PTT were prolonged, consistent with TIC
in this patient population; though reflecting only loss of procoagulant
proteins. There was a trend toward a small peak in PT around 24-36 hours
postoperatively, but this varied with several outliers. PTT tended to
rise with time in the postoperative period but was only collected on a
few patients (n=11).
CBL and transfusion rates in our cohort were similar to that reported in
other large cohorts.3,14,16,17,25 Intraoperative CBL
for the cohort was 34 mL/kg, reflecting a percentage of total blood
volume (BV) loss of 44%. Postoperative CBL was 12 mL/kg ( total BV loss
of 15%). We evaluated laboratory parameters to determine if they could
be predictive of BL (Table 2). Intraoperative laboratory values did
predict perioperative CBL. A lower intraoperative platelet count and
fibrinogen predicted lower intraoperative CBL; lower intraoperative
platelet count also predicted lower postoperative CBL. However, it is
important to note that none of these patients were thrombocytopenic nor
hypofibrinogenemic. In contrast, a higher intraoperative PT was
associated with increased intraoperative CBL and a higher postoperative
PTT was associated with increased postoperative CBL, possibly reflecting
procoagulant protein losses or a more abnormal coagulation state.
Postoperative laboratory values were not predictive of postoperative BL.
In our laboratory analysis, there was no significant difference in
hematologic or coagulation laboratory parameters between patients
receiving EACA vs. TXA. While there were no differences in laboratory
parameters between the two cohorts, postoperative laboratory trends
suggest ongoing disturbance of the hemostatic system beyond the
operative period (Supplemental Figure 1). This includes an expected fall
in hematocrit with a delayed improvement despite transfusion, a
continuous rise in fibrinogen postoperatively, and in some patients, a
persistently prolonged PTT. These results were limited by sampling in
this observational study, not providing mechanistic data, but may
provide an impetus for future laboratory investigation in this
population.
Prior groups have looked at viscoelastic assays in pediatric CCVR as a
potential alternative to monitoring standard coagulation
assays.19,21,30,31 Global assays of hemostasis, such
as thromboelastography, potentially provide more useful information, but
have their own limitations.20,21,30–32 This testing
was not performed routinely in our cohort. Our data set was insufficient
to draw firm conclusions about coagulopathy but suggests that future
prospective laboratory-based studies looking at alternative coagulation
assays may help elucidate some of the mechanisms of surgically-induced
coagulopathy. Better understanding of the mechanisms of coagulopathy in
CCVR has the potential to improve BL and surgical outcomes for children
with craniosynostosis. A prospective study analyzing additional
perioperative laboratory markers such as plasminogen activity,
plasmin-antiplasmin complexes, markers of platelet activation by flow
cytometry, and inflammatory cytokines would be beneficial in improving
our understanding of TIC and BL in craniofacial surgery.