CTEPH patients have thrombophilic tendencies
MedWire News: Patients with chronic thromboembolic pulmonary hypertension (CTEPH) may have both hereditary and acquired risk factors for thrombosis, study findings demonstrate.
“This is in keeping with other lines of evidence that suggest pulmonary embolism is an important primary event in development of this disorder,” comment lead author Chieh Wong and co-workers, from Hammersmith Hospital in London, UK.
The team recruited 245 patients with PH, of whom 45 had CTEPH and 200 had congenital or idiopathic PH or secondary PH from other causes.
The patients were examined for thrombophilic genetic variants of antithrombin, protein C or protein S, and the factor (F)V Leiden and prothrombin G20210A gene mutations. In addition, blood samples were examined for von Willebrand factor (VWF), antiphospholipid antibodies (APA), lupus anticoagulant, and fibrinogen.
Patients with CTEPH were significantly more likely than other PH patients to carry the FV Leiden mutation (29.0% vs 7.8%), and there was a trend to an increased likelihood for the prothrombin G20210A mutation (9.7% vs 3.1%).
Patients with CTEPH and those with other forms of PH did not significantly differ with regard to levels of antithrombin, protein C or protein S, but this may have been due to the widespread use of warfarin, the researchers note.
The two groups were also comparable for acquired thrombophilic factors of APAs, and again warfarin treatment made it difficult to assess lupus anticoagulant status.
However, although both patient groups had levels of FVIII and VWF above the normal limit, the levels were significantly higher in CTEPH patients than those with PH of other causes.
Furthermore, levels of FVIII and VWF correlated with fibrinogen in patients with non-CTEPH, suggesting that “elevation of FVIII-VWF may be secondary to inflammation in this group and associated disorders,” the researchers say. No such relationship was found for the CTEPH patients.
“The results indicate different pathophysiologies for CTEPH and non-CTEPH,” Wong et al conclude in the journal Blood Coagulation and Fibrinolysis.
“The elevation of FVIII and increased incidence of FV Leiden gene polymorphisms in the CTEPH group support a primary role of thrombosis in aetiology.”
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By Lynda Williams