Editorial: short‐length stenoses of hepatic venous outflow tract – an Asian specificity?

It remains unclear to what extent findings in western patients with hepatic venous outflow tract obstruction can be extrapolated to Asian patients, and reciprocally. Shalimar et al., from Delhi, India, have recently reported in Alimentary Pharmacology & Therapeutics an important analysis of interventional radiology for hepatic venous outflow tract obstruction,1 one in a growing list of recent studies from Asia.2 The strengths of these findings include a large number of patients (n = 334) and a recent study period (2006–2014); a comprehensive description of patients and a relatively homogeneous management. Similar to Europe3 but at variance with common belief,2 almost all patients had an obstruction of the hepatic veins, and half had an associated IVC obstruction. However, short-length stenosis (<3 cm in length) was more common in Delhi patients with hepatic vein obstruction (about 50%) than in Europe (29%).4 Recanalisation was achieved in 90% of patients, and this was associated in a complete response in a majority. In Europe, only 5% of patients had angioplasty as the definitive treatment.3 The difference between the two areas is not fully explained by a higher proportion of short-length stenosis in Delhi, as recanalisation was also achieved in 55% patients with long-segment stenosis. Furthermore, it is noteworthy that among 117 patients with combined IVC and hepatic vein obstruction, a complete response was observed in 70% although intervention was limited to the recanalisation of IVC alone in 50%, while only 40% underwent recanalisation of IVC and hepatic veins and less than 10% TIPSS insertion. Thus, a partial relief of obstruction could be sufficient to control the clinical manifestations of hepatic venous outflow tract obstruction in many patients. Several factors limit the interpretation. Median follow-up was only 18 months, and one-third of the patients were lost to follow-up. Aetiology was incompletely investigated. Approximately half the patients had a disease of mild to moderate severity at inclusion (median Child–Pugh score and MELD 6 and 10, respectively; no or low-grade oesophageal varices in over 60% of patients; no ascites in 20%). Technical success was estimated from a subjective appreciation of flow restoration, not from the fall in pressure gradient across stenosis. Complete response was defined as a mix of technical success and decrease in diuretic requirement. Anti-coagulation was given only to patients subjected to a radiological intervention, whereas a report from Mumbai indicates that anti-coagulation alone can achieve a complete clinical and laboratory response in 61% of patients followed up at a median of 21 months.5 The high proportion of short-length stenosis of the hepatic venous outflow tract in patients with hepatic venous outflow tract obstruction seen in Delhi is intriguing. Further follow-up data as well as reports from other Asian areas are needed to derive firm conclusions on the benefit of adding radiological recanalization to anti-coagulation therapy alone in patients with a mild to moderate disease. Still, this paper invites western specialists to revive their attention for short-length stenosis of hepatic venous outflow tract, and to revisit recanalisation, even if partial, as a means for controlling the hepatic venous outflow tract obstruction in a most physiological way. Declaration of personal and funding interests: None.

Topic: Liver Disease and Transplantation
Subfield: Hepatology
Field: Medicine
Domain: Health Sciences