Association between PAI-1 4G/5G genotype and residual thrombus in acute mesenteric venous thrombosis.

Objective: Plasminogen activator inhibitor-1 (PAI-1) is the most important inhibitor of plasminogen activator. The functional 4G/5G polymorphism of the gene coding for PAI-1 may affect PAI-1 plasmatic activity, influencing the imbalance between coagulation and fibrinolysis cascades. In this study, we investigated the association between the PAI-1 4G/5G genotype and the development and residual thrombus of acute primary mesenteric venous thrombosis (MVT).

Methods: The clinical data of 34 patients who underwent acute primary MVT were retrospectively reviewed. Fluorescence in situ hybridization was used to determine if patients had the 4G/5G polymorphism in the promoter of the PAI-1 gene. Patients were stratified according to the genotype of PAI-1.

Results: 11 patients (32.3%) were homozygous for the 4G genotype, 23 patients (67.6%) were non-homozygous for the 4G genotype (5G/5G). The extent of thrombosis was not correlated with the PAI-4G/5G polymorphism. After a mean follow-up of 16.6 ± 10.4 months, the 4G/4G genotype had a significantly larger thrombus burden (p < 0.05). 54% of patients in the 4G/4G genotype group had no lessening in the degree of mesenteric venous thrombosis, significantly higher than other patients (4G/5G + 5G/5G genotypes) (p < 0.05).

Conclusion: The PAI-1 4G/4G predicts residual thrombus of mesenteric veins after the acute phase.