S5768 Rare Splenic Arteriovenous Fistula Causes Reversible Portal Hypertension

Introduction: Portal hypertension is most often associated with cirrhosis and can lead to complications like ascites and varices. However, vascular irregularities such as splenic arteriovenous fistulas (AVF) can have similar presentations to cirrhotic portal hypertension. Although splenic AVFs are rare, occurring in 0.04% of the general population, a delay in diagnosis can lead to unnecessary testing and potentially avoidable consequences. Case Description/Methods: A 79-year-old man with a past medical history of stage 4 chronic kidney disease, coronary artery disease, severe aortic regurgitation, and heart failure with reduced ejection fraction was initially admitted for new-onset ascites and splenomegaly. He had a diagnostic paracentesis showing a serum-ascites albumin gradient of 2.8, consistent with portal hypertension. Direct liver-related causes were ruled out with negative hepatitis studies and normal liver enzymes. His presentation was thought to be caused by acute decompensated heart failure due to his extensive cardiac history and mildly elevated troponins. With symptomatic improvement, he was discharged for outpatient cardiology follow-up. Three days later, he presented again with reaccumulating ascites, and a repeat paracentesis was consistent with the prior diagnosis of portal hypertension. GI was consulted for the unexplained portal hypertension and they recommended additional imaging with an abdominal ultrasound. The ultrasound showed concern for a splenic pseudoaneurysm, and a follow up computed tomography angiography showed it to be a splenic AVF. Interventional radiology performed a coil embolization to decrease flow through the AVF. At his 6-week follow-up, repeat imaging demonstrated resolution of the splenic AVF, improvement in splenomegaly, and no recurrence of ascites. Discussion: This case illustrates a rare incidence of splenic AVF leading to portal hypertension. By treating the underlying cause with the coil embolization, the patient was able to avoid additional procedures and long-term consequences of untreated portal hypertension. It is important to maintain a broad differential and recognize alternative causes of portal hypertension, such as vascular malformations, when more common etiologies are ruled out.