A medical device that tests to see if endothelial cells are damaged. Endothelial cells line the inner walls of blood vessels, lymph vessels, and the heart, and damage to them may be an early sign of heart disease. Endo-Pat 2000 looks for heart disease by using sensors that measure blood flow through a patient’s fingers. It is also being used to check blood vessels in patients treated for breast cancer. Also called EndoPat.