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Idiopathic pulmonary arterial hypertension – a unrecognized cause of high‐shear high‐flow haemostatic defects (otherwise referred to as acquired von Willebrand syndrome) in children
Author(s) -
PellandMarcotte MarieClaude,
Humpl Tilman,
James Paula D.,
Rand Margaret L.,
Bouskill Vanessa,
Reyes Janette T.,
Bowman Mackenzie L.,
Carcao Manuel D.
Publication year - 2018
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1111/bjh.15530
Subject(s) - medicine , von willebrand factor , pulmonary hypertension , cardiology , thrombosis , bleeding diathesis , platelet , von willebrand disease , gastroenterology
Summary Acquired von Willebrand syndrome ( AVWS ) is reported in high‐flow high‐shear congenital cardiac disorders. We hypothesized that the narrowed pulmonary vasculature in idiopathic pulmonary arterial hypertension ( IPAH ) may induce AVWS . We conducted a cross‐sectional evaluation of children with IPAH . Patients with bleeding symptoms and/or laboratory abnormalities (thrombocytopenia, anomalies in coagulation screening tests) were tested in‐depth for haemostatic defects. Fourteen children were followed with IPAH of which 8 were eligible. Four children exhibited abnormal bleeding scores (International Society on Thrombosis and Haemostasis Bleeding Assessment Tool: 3–5). All 8 patients showed very prolonged platelet function analyser ( PFA )‐100 closure times. Six children demonstrated either mild thrombocytopenia or low‐normal von Willebrand factor ( VWF ) antigen ( VWF :Ag) or VWF activity [mean (range), in iu/dl: VWF :Ag: 70 (61–91); VWF activity: 57 (34–70)]. Average VWF collagen binding capacity ( VWF : CB ) was 64 iu/dl (range: 53–123 iu/dl), with low‐normal VWF activity/ VWF :Ag or VWF : CB / VWF :Ag ratios occurring in five patients. All children had normal multimers distribution patterns. One patient underwent a lung transplantation, with normalization of haemostatic abnormalities post‐surgery. Overall, 8 out of 14 children with IPAH had mild to moderate bleeding symptoms and/or laboratory abnormalities in keeping with AVWS . Normalization of the haemostatic defects following lung transplantation and lack of family history of bleeding attests to the acquired nature of their defects.