<qa>  What is the main exclusion criteria for VA patients?The study is a prospective, randomized, unblinded clinical trial. The population consists of VA patients with coronary artery disease documented by coronary arteriography and who have agreed to undergo coronary artery bypass surgery. Medical conditions which could affect blood flow through the patients arm are the main exclusion criteria. These include Raynauds symptoms, positive Allen test, neurologic or musculoskeletal disease affecting the arm and patients with one arm. 