Question

A 76-year-old male patient arrives at the emergency department reporting excruciating, sudden-onset abdominal pain that began three hours prior to evaluation. His past medical history is notable for hypertension, type 2 diabetes mellitus, and chronic atrial fibrillation, though he admits to frequently missing doses of his oral anticoagulant. His temperature is 37.9°C (100.2°F), blood pressure is 105/65 mm Hg, pulse is 122/min and irregularly irregular, and respirations are 24/min. On physical examination, the patient appears in distress and is writhing in bed. The abdomen is mildly distended and diffusely tender, but there is no rigidity or rebound tenderness. Bowel sounds are hypoactive. Laboratory studies show a leukocyte count of 19,500/mm³ and a serum lactate level of 4.8 mmol/L. A contrast-enhanced CT scan of the abdomen and pelvis reveals a focal filling defect in the proximal superior mesenteric artery. Additional imaging findings include diminished mucosal enhancement in the distal jejunum and small, linear branching lucencies in the periphery of the liver. Based on the interpretation of these imaging findings, which of the following is the most appropriate next step in management?