Summary
Three to five percent of patients undergoing surgery have either an acquired or congenital
platelet defect or von Willebrand disease (vWD). The predictive value of preoperative
coagulation screening is questionable. PFA-100 is now routinely used in preoperative
screening in our pediatric outpatient service. We wanted to assess whether the PFA-100
would help to identify patients with primary haemostatic defects or if the additional
use of PFA-100 would add to the problem of unnecessary pathologic preoperative laboratory
values resulting in delay of surgical procedure. We investigated 500 children consecutively
seen in our outpatient service before surgery. Blood cell count, aPTT, PFA-100 closure
times (CT) were done in all patients. If abnormalities were found, the patient was
presented to a haemostatic expert. vWF:AG, R:Cof and factorVIII were analysed in all
patients with prolonged closure times and APTT values. One hundred twenty-six patients
(25.2%) showed abnormalities in APTT and/or PFA-100. Further investigations in 89
of these 126 patients did not yield a specific diagnosis; neither diagnostic criteria
for impaired haemostasis were found by questionnaire. None of these 89 patients had
a bleeding complication during surgery. Forty-eight patients showed prolonged CTs.
Twelve patients with low vWF:AG were detected, 10 of these patients were found by
PFA-100. Four of these patients did present with normal APTT values. Our study shows
that similar to the APTT the PFA-100 is probably only a good screening method when
a haemostatic defect in a patient is clinically likely, especially to screen forVWD,
and the test should not be used in general unselective screening.
Keywords
Paediatric haemostasis - von Willebrand disease - closure time
