Impact of catheter tip to hepatic vein ostium distance on the validity and prognostication of hepatic venous pressure gradient in cirrhosis

Hepatic venous pressure gradient (HVPG) is an accurate measure of portal hypertension in cirrhosis. However, the effect of catheter tip distance from hepatic vein ostium (HVO) on HVPG is unknown. We performed a retrospective study on 228 patients with 307 HVPGs in our institution. The objectives of this study were to assess the effect of catheter position on the validity of HVPG and its prognostication in cirrhosis. In this study, free hepatic vein pressure (FHVP) was considered optimal when difference between FHVP and inferior vena cava pressure was <= 2 mmHg. HVPG progressively decreased (p < 0.001) when measured at increasing distance from HVO due to an increasing FHVP (p = 0.036) but an unchanged wedged hepatic vein pressure (p = 0.343). Catheter tip distance > 5 to <= 8 cm [odds ratio {OR} 0.16 (95% CI 0.05-0.47), p = 0.001] and > 8 cm [OR 0.14 (95% CI 0.04-0.47), p = 0.002] compared to <= 3 cm from HVO were independent predictors of not achieving optimal FHVP. Baseline HVPG >= 16 mmHg was strongly associated with deaths due to cirrhosis and liver transplantation for end-stage liver disease compared to HVPG < 16 mmHg when FHVP was optimal (p < 0.001) but not when it was suboptimal (p = 0.359). Our study showed that FHVP is spuriously elevated when measured at > 5 cm from HVO, resulting in inaccurately low HVPG.