TY - JOUR
T1 - Evaluation of primary haemostasis in people with neurofibromatosis type 1
AU - Favaloro, E J
AU - Zafer, M
AU - Nair, S C
AU - Hertzberg, M
AU - North, K
PY - 2004/10
Y1 - 2004/10
N2 - Assessment of haemostasis in people with neurofibromatosis type 1 (NF-1) is essentially lacking, despite case reports of an association with von Willebrand disorder (VWD) and reported excessive bleeding post-surgery. We assessed routine blood haematology, routine coagulation parameters [prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT) and fibrinogen], coagulation factors II, V, VII, VIII, IX, X, XI and XII, von Willebrand (VWF) factor antigen and activity, and platelet function [using the platelet function analyser (PFA-100)] in a group of individuals with NF-1 (n = 30). Their perceived haemorrhagic bleeding risk was also graded by means of a structured clinical assessment and physical examination. Routine blood assessments including platelet counts were generally normal, as were the routine coagulation tests PT, TT and fibrinogen, and most coagulation factors. Elevated APTTs were detected in 11 individuals, reduced factor XII levels in three, reduced VWF levels in four, and elevated PFA closure times (CTs) in 13. Laboratory results correlated with each other in some but not all cases. For example, elevated APTTs were identified in two of three individuals with a reduced factor XII level and prolonged CTs were identified in three individuals who also showed reduced aggregation responses in classical platelet function studies. Moreover, all individuals with VWF results below the normal reference range showed elevated CTs with both PFA test cartridges, and those with VWF results identified as borderline normal (i.e. 50-65%) also showed elevated CTs with both PFA test cartridges in three of five cases. The relationship between VWF and CTs was also identified by linear regression analysis (P-values of <0.05, for all comparisons). However, as clinically perceived bleeding risk did not appear to be correlated with laboratory test results in most cases, blanket screening of NF-1 individuals for evaluation of laboratory haemostasis may not be warranted.
AB - Assessment of haemostasis in people with neurofibromatosis type 1 (NF-1) is essentially lacking, despite case reports of an association with von Willebrand disorder (VWD) and reported excessive bleeding post-surgery. We assessed routine blood haematology, routine coagulation parameters [prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT) and fibrinogen], coagulation factors II, V, VII, VIII, IX, X, XI and XII, von Willebrand (VWF) factor antigen and activity, and platelet function [using the platelet function analyser (PFA-100)] in a group of individuals with NF-1 (n = 30). Their perceived haemorrhagic bleeding risk was also graded by means of a structured clinical assessment and physical examination. Routine blood assessments including platelet counts were generally normal, as were the routine coagulation tests PT, TT and fibrinogen, and most coagulation factors. Elevated APTTs were detected in 11 individuals, reduced factor XII levels in three, reduced VWF levels in four, and elevated PFA closure times (CTs) in 13. Laboratory results correlated with each other in some but not all cases. For example, elevated APTTs were identified in two of three individuals with a reduced factor XII level and prolonged CTs were identified in three individuals who also showed reduced aggregation responses in classical platelet function studies. Moreover, all individuals with VWF results below the normal reference range showed elevated CTs with both PFA test cartridges, and those with VWF results identified as borderline normal (i.e. 50-65%) also showed elevated CTs with both PFA test cartridges in three of five cases. The relationship between VWF and CTs was also identified by linear regression analysis (P-values of <0.05, for all comparisons). However, as clinically perceived bleeding risk did not appear to be correlated with laboratory test results in most cases, blanket screening of NF-1 individuals for evaluation of laboratory haemostasis may not be warranted.
KW - Adolescent
KW - Adult
KW - Blood Coagulation Factors/analysis
KW - Blood Coagulation Tests
KW - Child
KW - Female
KW - Hematologic Tests
KW - Hemorrhage/etiology
KW - Hemostasis
KW - Humans
KW - Male
KW - Middle Aged
KW - Neurofibromatosis 1/blood
KW - Platelet Function Tests
KW - Regression Analysis
KW - von Willebrand Factor/analysis
U2 - 10.1111/j.1365-2257.2004.00632.x
DO - 10.1111/j.1365-2257.2004.00632.x
M3 - Article
C2 - 15485464
SN - 0141-9854
VL - 26
SP - 341
EP - 345
JO - Clinical and Laboratory Haematology
JF - Clinical and Laboratory Haematology
IS - 5
ER -