<prompt> Most common arterial involvement causing ischemia of intestine is:Superior mesenteric artery thrombosisInferior mesenteric artery thrombosisHepatic artery thrombosisCeliac artery thrombosis  <response>: Ans: A Superior mesenteric artery thrombosis Ref: Schwartz Textbook of Surgery, 10th edition, pg: 860; Mastery of Vascular and Endovascular Surgery - Gerald B. Zelenock - 2006, pg: 294 and Essentials of General Surgery, Peter F. Lawrence, 2006, pg: 459Explanation:The SMA is the most commonly involved vessel in acute mesenteric ischemiaRef: Mastery of Vascular and Endovascular SurgeryEmbolization to the superior mesenteric artery accounts for approximately 50 of ail cases of acute mesenteric ischemia Ref: Essentials of General SurgerySuperior Mesenteric Artery EmbolusMost common cause of mesenteric ischemia 40 to 50 of cases.The prognosis is poor 70 mortality.Sudden embolus with no time for collaterals to form.Presents with abdominal pain out of proportion to examination findings.Risk Factors:o Arrhythmias atrial fibrillation,o Post-myocardial infarction with mural thrombi,o Valvular heart disease.o Structural heart defects.Superior Mesenteric Artery ThrombosisAccounts for 25 to 30 of mesenteric ischemia cases.Has worst prognosis with a mortality of 90.Occurs near the origin of the SMA.Causes enormous amount of bowel necrosis.Most patients have a history of chronic mesenteric ischemia with vague and insidious symptoms such as:o Weight loss.o Abdominal angina abdominal pain after meals,o Diarrhea,o Fear of food.Risk Factors:o Systemic atherosclerosis,o Old age.Angiography is the gold standard for mesenteric ischemia allowing for diagnosis and therapy. 