Peripancreatic Vascular Involvement and Gastric Varices in Autoimmune Pancreatitis: A Multicenter Retrospective Study

Abstract

Background & aims: Autoimmune pancreatitis (AIP) could induce peripancreatic vascular involvement, such as portal system stenosis, through inflammatory extension, resulting in the development of collateral vessels. In severe cases, gastric varices may develop, leading to a life-threatening risk of variceal rupture. However, these complications remain underrecognized and are not explicitly addressed in the current clinical guidelines. This study aimed to evaluate the frequency of vascular involvement in AIP, assess therapeutic effects of glucocorticoids, and identify key vessels associated with gastric varices.

Methods: This multicenter retrospective study included 230 patients diagnosed with AIP at 17 institutions in Japan between 2010 and 2021. We analyzed clinical data, contrast-enhanced computed tomography images, and endoscopy findings. All images were evaluated individually by 3 professionals at a central facility. The primary outcome was the frequency of peripancreatic vascular involvement.

Results: At diagnosis, 51.3% of the patients exhibited peripancreatic vascular involvement, primarily in the splenic vein (48.3%), superior mesenteric vein (23.9%), and portal vein (9.6%). Collateral vessel formation was observed in 40.0% of patients, with 24.3% being severe; 2 gastric variceal ruptures occurred prior to therapy. Glucocorticoid therapy significantly improved venous stenosis (response rates: 95.6%, 93.8%, and 93.1% in the splenic, portal, and superior mesenteric veins, respectively). Additionally, 80.9% of patients exhibited collateral vessel improvement. Among 55 patients who underwent upper endoscopy, 10.9% had gastric varices strongly associated with severe splenic vein stenosis.

Conclusions: Peripancreatic vascular involvement represents a common complication of AIP and significantly responds to glucocorticoid therapy, underscoring the importance of careful monitoring to prevent potentially fatal outcomes.

Keywords: Autoimmune Pancreatitis; Gastric Varices; Peripancreatic Vascular Involvement; Therapeutic Response.