A 68-year-old woman presents with severe abdominal pain after meals and significant weight loss. The most likely cause of her symptoms is stenosis of which artery?

In this scenario, the patient's symptoms of severe abdominal pain after meals and significant weight loss suggest the presence of mesenteric ischemia, which is often associated with stenosis of the superior mesenteric artery.

The superior mesenteric artery supplies blood to a significant portion of the intestines including the small intestine and the proximal colon. When there is stenosis (narrowing) of this artery, blood flow to these areas can be compromised, especially during digestion when the intestines require increased blood supply. This can result in postprandial abdominal pain, as the body struggles to provide adequate circulation to the intestines in response to the increased demands after eating.

The weight loss can be attributed to the patient's avoidance of food intake due to pain, leading to decreased caloric consumption. This condition is particularly common in older adults, who may have atherosclerosis leading to arterial occlusive disease.

In contrast, the other arteries listed either supply different regions or would not typically lead to the specific symptoms described. The greater pancreatic artery primarily serves the pancreas, the hepatic artery supplies the liver, and the right gastric artery primarily supplies part of the stomach. Thus, they are less likely to be the cause of the symptoms in this case.