Thrombotic risk factors in Chinese nonmalignant and noncirrhotic patients with portal vein thrombosis: an observational study with a systematic review of the literature.

BACKGROUND

Until now, no data on the routine screening for thrombotic risk factors in Chinese nonmalignant and noncirrhotic patients with portal vein thrombosis (PVT) have been reported.

METHODS

A total of 141 nonmalignant and noncirrhotic patients with PVT who underwent screening tests for thrombotic risk factors between September 2009 and August 2012 were included in this study.

RESULTS

The JAK2 V617F mutation was found in 35 of the 141 patients tested. Neither the JAK2 exon 12 mutation nor the MPL W515 L/K mutation was found in any of the 50 patients tested. Overt myeloproliferative neoplasms (MPNs) were diagnosed in 13 patients (polycythemia vera, n=1; essential thrombocythemia, n=9; idiopathic myelofibrosis, n=3). Latent MPNs were considered in 23 patients with the JAK2 V617F mutation but without any significant abnormalities, as determined through regular blood tests. Anticardiolipin IgG antibodies were positive in none of the 136 patients tested. Paroxysmal nocturnal hemoglobinuria was not found in any of the 141 patients tested. Neither the factor V G1691A mutation nor the factor II G20210A mutation was found in any of the 72 patients tested. The C677T mutation in 5,10-methylenetetrahydrofolate reductase (MTHFR) was found in 29 of the 38 patients tested. Hyperhomocysteinemia was detected in eight of the 39 patients tested.

CONCLUSION

MPNs are an important thrombotic risk factor in Chinese patients with PVT. However, the extreme rarity of paroxysmal nocturnal hemoglobinuria, anticardiolipin IgG antibodies, and factor V G1691A and factor II G20210A mutations has precluded any support for the implementation of routine screening for these thrombotic factors in such patients. Additional case-control studies should confirm the role of the MTHFR C677T mutation and hyperhomocysteinemia in the pathogenesis of PVT.