The Natural History of Pancreatitis-Induced Splenic Vein Thrombosis

Though first recognized over 80 years ago as a cause of gastrointestinal hemorrhage,1 the natural history of pancreatitis-induced splenic vein thrombosis with subsequent gastric variceal bleeding remains poorly defined. Historically, 45% to 72% of patients with splenic vein thrombosis presented with gastric variceal bleeding,2 and the overwhelming majority of these patients underwent splenectomy. The reported frequency of splenic vein thrombosis, however, has increased recently due to significant advances in cross-sectional diagnostic imaging. In the remote past, splenic vein thrombosis was recognized only on postmortem examination,1 but studies such as celiac angiography and splenoportography have proved useful as diagnostic imaging has evolved. Increasingly sensitive, noninvasive studies such as computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound (US) are currently obtained frequently in the evaluation of patients with acute or chronic pancreatitis, and splenic vein thrombosis is identified. Splenic vein thrombosis complicates pancreatitis or pancreatic pseudocysts in 7 to 20% of patients, and it is not infrequently diagnosed as patients’ symptoms are resolving.3,4 Because splenic vein thrombosis is more readily detected with improved imaging and early gastric variceal bleeding is uncommon, an opportunity to document the natural history of this disease has arisen. Previous studies cited the frequency of gastric variceal hemorrhage as the critical event determining the management, either observation3,5 or splenectomy.2,3,6–8 An accurate assessment of the incidence of pancreatitis-induced splenic vein thrombosis and the frequency of gastric variceal hemorrhage, however, has been limited by several factors. First, the inclusion of pancreatic malignancies and extrapancreatic etiologies as a cause of splenic vein thrombosis and gastric variceal bleeding confounded the diagnosis and limited our ability to determine the long-term risks. In addition, the lack of a reliable diagnostic imaging modality impaired early diagnosis and follow-up examination. Therefore, our aim was to determine the natural history of pancreatitis-induced splenic vein thrombosis with specific attention to the development of gastric variceal hemorrhage. We found that only 4% of patients with pancreatitis-induced splenic vein thrombosis developed clinically evident, gastric variceal bleeding during follow-up.