Evaluating platelet function disorders in children with bleeding tendency – A single center study

Abstract

Platelet function disorders (PFDs) are a common cause of mild bleeding tendency. However, they cannot be recognized by standard screening studies. The gold standard test for PFD is platelet aggregation, performed by light transmission aggregometry (LTA). A newer and less validated method is the closure time (CT), performed by the platelet function Analyzer 100 (PFA-100). Data regarding the validity of these tests in children are limited. The aim of this study was to evaluate the usefulness of LTA and PFA-100 for the diagnosis of pediatric patients with bleeding tendency. This retrospective study included patients one month-18 year old that had LTA tests performed at the coagulation laboratory of Rabin Medical Center between the years 2006-2015. Bleeding severity was assessed using a pediatric bleeding score. Patients were excluded from analysis if they had thrombocytopenia, thrombocytosis or coagulation factors deficiencies. One hundred and thirty-seven (137) patients were included in the analysis. The median age was 7.5 years (range one month-18 years). Most patients (93%) had a bleeding score of 2 or more. Abnormal LTA was found in 40% and prolonged CT in 23% of the patients. Abnormal LTA was significantly more common in patients with a bleeding score of 2 or more compared to patients with a lower bleeding scores (P = 0.04). No significant correlation was found between the bleeding severity and the number of agonists which induced abnormal responses (p = 0.52) or the CT (p = 0.35). Furthermore, no correlation was found between abnormal LTA and prolonged CT. To conclude, we were able to diagnose 40% of children who presented with bleeding tendency with platelet aggregation defects by LTA. Abnormal LTA was significantly more prevalent in patients with a bleeding score of 2 and above. In contrast, CT was not found to be sensitive as a screening tool for PFD. Therefore, our data extend the validity of the use of LTA for the evaluation of pediatric patients with bleeding tendency.

Changes in and significance of platelet function and parameters in Kawasaki disease

“…However, our study unexpectedly observed that ADP in the defervescence period of KD was slightly prolonged compared with that in the febrile period of KD or that in the defervescence period of the febrile control group. Except for other factors, such as the reduced hematocrit or platelet count 25 , it indicates that IVIG can inhibit platelet activation in KD patients, as reported in previous studies 26,27 .…”

Executive Summary of Recommendations and Expert Consensus for Plasma and Platelet Transfusion Practice in Critically Ill Children: From the Transfusion and Anemia EXpertise Initiative—Control/Avoidance of Bleeding (TAXI-CAB)

“…Platelet dysfunction or acquired von Willebrand syndrome may result from blood circulation through mechanical circuitry (such as CPB, ECMO, ventricular assist devices, or hemofiltration), renal failure, or pharmacologic agents (such as antiplatelet agents, nonsteroidal anti-inflammatories, or milrinone) (37). Platelet aggregation studies may provide additional information in children who are at high risk of bleeding from platelet dysfunction; in those children, total platelet count should not be the sole indication for platelet transfusion (38). Clinicians must consider the etiology of the thrombocytopenia and/ or coagulopathy when deciding to transfuse.…”

Comparison Between Bleeding Time and PFA-200 to Evaluate Platelet Function Disorder in Children

“…Citrated whole blood is applied to a test cartridge that contains a collagen-coated membrane and either epinephrine (Col/Epi) or adenosine diphosphate (Col/ADP). 2,3 The PFA-200 has been used to detect acquired and congenital platelet dysfunctions 4,5 and to screen for von Willebrand disease (vWD) in adults. The 2 test cartridge system was developed to differentiate between the effects of nonsteroidal anti-inflammatory drugs 6,7 and other types of qualitative defects in platelets.…”