Lippi et al described paradoxical thrombosis and listed possible causes. The authors are from Azienda Ospedaliero-Universitari di Parma, Westmead Hospital (Australia) and Ospedale Carlo Poma in Mantua.


Paradoxical thrombosis refers to the occurrence of a thrombosis in a patient when it seems counterintuitive (prolonged aPTT, anticoagulation, etc).


Situations where paradoxical thrombosis may occur:

(1) hemophilia A during factor replacement

(2) hemophilia B during factor replacement

(2) von Willebrand’s disease during factor replacement

(4) Factor XII deficiency (Hageman factor)

(5) Factor VII deficiency

(6) disorders of fibrinogen

(7) lupus anticoagulant (despite prolonged aPTT)

(8) when starting warfarin therapy without heparin (due to loss of protein A and C)

(9) heparin anticoagulation (heparin-induced thrombocytopenia)

(10) aspirin resistance

(11) resistance to GPIIb/IIIa inhibitors

(12) clopidogrel therapy (due to clopidogrel-related TTP)


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