Systemic inflammation as a risk factor for portal vein thrombosis in cirrhosis: a prospective longitudinal study.

Background and aims Various risk factors for portal vein thrombosis (PVT) development in patients with cirrhosis have been identified, but the role of systemic inflammatory reaction is unknown. The study aims to assess the association between markers of systemic inflammation and PVT in cirrhosis. Methods Between January 2014 and October 2015, 107 outpatients with cirrhosis and no PVT were recruited, and followed till February 2017. White blood cell count, serum concentrations of high-sensitive C-reactive protein, ferritin, tumor necrosis factor-alpha and interleukin-6 (IL-6) were evaluated at baseline and every 3 or 6 months till PVT diagnosis or end of follow-up. Results Median age, model for end-stage liver disease (MELD) score and follow-up period of the studied population was 55 years (IQR 46-62 years), 9.6 points (IQR 7.5-12 points) and 19 months (12-24 months), respectively. PVT developed in 10.3% of the patients. Lymphocyte count below 1.2 ´ 10/L [hazard ratio, 6.04; 95% confidence interval (CI), 1.29-28.2; P = 0.022], IL-6 above 5.5 pg/mL (hazard ratio, 5.64; 95% CI, 1.21-26.33; P = 0.028) and neutrophil-to-lymphocyte ratio (hazard ratio, 1.46; 95% CI, 1.04-2.04; P = 0.028) were associated with a higher risk of PVT development. IL-6 and lymphopenia remained associated with subsequent PVT development after adjustment for nonselective beta-blockers, spleen size, portosystemic collaterals, oesophageal varices (grade ≥2) and ascites, but also with alcohol as the cause for cirrhosis and MELD ≥13. Conclusion In patients with cirrhosis, markers of systemic inflammation IL-6 and lymphopenia are predictive of PVT independently of markers of portal hypertension. These results draw our attention on a factor so far overlooked in the pathogenesis of PVT.