Recently in Gastroenterology Category

This is an 88 year old man with PMH CAD s/p bare-metal coronary stent placement, h/o TIA on aspirin-dipyridamole, s/p left carotid endarterectomy, CRI stage IV, HTN, and dementia who presents with three days of non-bilious, non-projectile, nonbloody vomitting and dark stools. On abdominal CT, pneumobilia is seen; what is the etiology?