<prompt> All are true about ischemic colitis except :IMA is commonly occluded in cases needing aoic ischemiaIschaemia is more common in small bowel as compared to large bowelMost common site of post ischemic structure is sigmoidTransection of IMA doesnt need reimplantation if aoic surgery is attempted  <response>: Indeed, the IMA is frequently occluded in conditions requiring aoic surgery, and in such circumstances, transection of the IMA does not require reimplantation. However, in this situation, the left colon is dependent on collateral blood supply, and transient hypotension at the time of the vascular procedure or immediately after surgery may result in ischemic injury to the vulnerable colonic mucosa In aoic surgery, the IMA is assessed for backbleeding. If there is strong backbleeding stump pressure 40 mmHg, the IMA is ligated close to the aoa or over sewn from within the sax. Poor backbleeding from the IMA is a sign of insufficient collateral circulation to the sigmoid colon, and reimplantation of the IMA with a patch of the aoa into the aoic limb is warranted Ref: Sabiston 20th edition Pgno : 1356 