What you need to do. If you currently have a JetBlue Card from American Express, just wait. You should receive the JetBlue RewardsÂ® MasterCardÂ® by mid-March. You can activate your new card beginning March 21 at 6 a.m. Eastern time. Until that time, you can continue to use your JetBlue Card from American Express as usual.
The blood supply to the colon comes from the superior and inferior mesenteric arteries. Part of the rectum is supplied by the internal iliac system and this anastamoses with the lower branches of the inferior mesenteric system.
The splenic flexure is a watershed between the SMA and IMA and is at particular risk of ischemia. Note that acute mesenteric ischemia is distinct from ischemic colitis (see Ischemic Colitis), which involves only small vessels and causes mainly mucosal necrosis and bleeding. Mesenteric blood flow may be disrupted on either the venous or arterial sides. In general, patients > 50 are at greatest risk and have the types of occlusions and risk factors shown in Causes of Acute Mesenteric Ischemia.