In the small bowel, 30 to 40% of bleeding is caused by abnormal blood vessels in the wall of the small bowel. These abnormal blood vessels have many names, including angioectasias, angiodysplasias, or arteriovenous malformations (AVMs).he small bowel (or small intestine) is the longest portion of the gastrointestinal (GI) tract. It is called small because it is thin or narrow compared with the large bowel (also known as the colon), but it is much longer than the large bowel (14 feet on average).
Don't forget the multiple causes of an elevated d-dimer: 1  PE/DVT. 2  Sepsis/infection. 3  Malignancy. 4  Renal disease. 5  Pregnancy. 6  MI. 7  Stroke.
Causes of high levels of AST. Elevated levels of AST may be triggered by damage of the liver due to conditions like cirrhosis and hepatitis. They may also be caused by decaying tumor or necrosis. Other conditions like heart attack, heart failure, kidney, and lung damage may also cause the AST levels to rise.