Splanchnic vein thrombosis (SVT) is a rare, heterogeneous, and potentially life-threatening condition with limited epidemiological data.

We did a nationwide, patient-level analysis of the Swiss Medical statistics including all patients hospitalized for SVT from 2003 to 2022. SVT was defined by a composite of available ICD-10 codes: I81 (portal vein thrombosis, PVT), I82.80 (splenic vein thrombosis), I82.0 (Budd-Chiari syndrome, BCS). Multisegmental vein thrombosis was defined as the concomitant presence of two or more of the previous codes. We gave a descriptive overview of demographic and admission data, along with trends over time in hospitalization length, prevalence, case fatality rate, and rehospitalization rates.

An episode of SVT was recorded in 17,966 inpatients, of whom 14,874 (82.8%) had PVT. The median age was 64 years (IQR 53-73), and 65% of the patients were male. Overall, 19% of patients required intensive care, reaching 26% in those with multisegmental vein thrombosis. Major concomitant conditions included malignancies, especially hepatic and biliopancreatic tumors, and myeloproliferative diseases (10% of BCS patients). Cirrhosis and liver diseases were common features of PVT patients, explaining the high rates of portal hypertension, liver failure, and ascites in this group. In all groups, we found high rates of gastrointestinal bleeding. Overall, 61% of SVT patients underwent gastrointestinal surgery. SVT prevalence (Figure) and rehospitalization rates increased over time, with different time dynamics depending on the type of thrombosis. Overall, 14% of patients died during the index hospitalization. The case fatality rate (Table) progressively decreased for PVT, it almost doubled for splenic vein thrombosis, and it slightly increased for BCS over time.

The epidemiological burden of SVT remained substantial over the past two decades, calling for research focusing on these conditions.