Usefulness of Cardiopulmonary Exercise Testing for Cardiovascular Risk Estimation and Frailty Assessment in Liver Transplant Candidates

Subjects will perform cardiopulmonary exercise testing which consists of biking on a cycle ergometer (recumbant stationary bicycle) while breathing through a mouthpiece or mask to measure the oxygen and carbon dioxide in the subject's breath. We will also do impedance cardiography, an FDA-approved test to check how the heart functions during exercise. For this test we will attach 6 electrodes (total) to the chest and back (similar to an EKG), so that we can measure the quantity of blood coming out of the heart on every heartbeat. Each evaluation will also include cardiac testing looking for coronary artery disease (CAD).