A 67-year-old male is diagnosed with a type B aortic dissection. At the time of initial presentation on the previous day, his blood pressure was 178/ 110 mmHg. He was treated with intravenous beta-blocker, and his blood pressure was reduced to 112/ 60 mmHg and has remained in that range. However, one day later, he suddenly develops severe abdominal pain. His blood pressure is measured to be 110/ 56 mmHg. Which of the following is the most likely explanation?
(A) C. difficile infection
(B) Occlusion of the superior mesenteric artery
(C) Pancreatitis
(D) Aortoenteric fistula
(E) Diverticulitis