Which artery is most likely occluded in a patient with ischemic bowel affecting the lower duodenum to the transverse colon?

The most likely artery to be occluded in a patient with ischemic bowel affecting the lower duodenum to the transverse colon is the superior mesenteric artery (SMA). The SMA supplies blood to the majority of the small intestine, including the jejunum and ileum, as well as the cecum, ascending colon, and most of the transverse colon.

In cases of ischemia affecting the lower duodenum specifically, the SMA's branches, particularly the inferior pancreaticoduodenal artery, may play a role, while the supply to the transverse colon is primarily through the middle colic artery, which is a branch of the SMA. As such, occlusion of the SMA can lead to ischemia in these regions due to decreased blood flow, potentially leading to bowel necrosis if not promptly addressed.

The coeliac artery primarily supplies the upper regions of the gastrointestinal tract, including the stomach, liver, and proximal duodenum, which are not directly involved in ischemia affecting the lower duodenum to the transverse colon. The inferior mesenteric artery mainly supplies the distal colon and rectum and would generally be relevant for ischemia lower than the transverse colon. The middle colic artery, while supplying some parts of the transverse colon