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.
A D-dimer test measures a substance in the blood that's released when a blood clot breaks down. High levels of the substance may mean a clot is present. If your test is normal and you have few risk factors, PE isn't likely. Other blood tests check for inherited disorders that cause blood clots. Blood tests also can measure the amount of oxygen and carbon dioxide in your blood. A clot in a blood vessel in your lungs may lower the level of oxygen in your blood.