Patients with marginal physiologic reserve, severe frailty, and/or malnutrition may be regarded as unsuitable candidates for advanced cardiac replacement therapies. However, little data exist on precisely which measures are predictive of subsequent adverse events. Assessment of nutritional status and frailty is still largely predicated on crude and obsolete parameters, such as baseline serum albumin level or body mass index (BMI). In this prospective cohort study the investigators will evaluate the use of bio-electrical impedance spectroscopy (BIS) as a measure of body composition and assess the associations with surgical outcomes.