Increasingly, the group of patients undergoing cardiac surgery are older. Patients that are more elderly and frail are known to have an increase risk of injury to major organs following surgery including the heart, kidneys, and brain, all of which are associated with worse survival or diminished quality of life. It is becoming more important to be able to predict how well patients will fair in cardiac surgery, including predicting risk of complications (such as stroke or heart attacks) as well as long-term survival and quality of life. Currently, scores such as EUROscore can be used with good effect in predicting survival and major complications in cardiac surgery patients. However, frailty - the severity of a patient's weakness or fragility - has emerged as a potential candidate in predicting risk. Recent research has shown frailty score to predict risk of survival and complications following cardiac surgery and suggested to be possibly superior to pre-existing scores. The investigators wish to investigate the possible link between frailty and outcomes following cardiac surgery, in addition to current risk scores. The investigators also wish to determine whether frailty can effectively predict longer-term outcomes such as 'disability-free survival' - a patient-centred score that measures the ability of a patient to lead normal life activities. Patients undergoing major cardiac surgery at King's College Hospital will be recruited, following consent. The study will mainly involve questionnaires at various stages, starting at a pre-operative clinic. After surgery, follow up of patient's progress will be carried out at 3 days in hospital; and at 1 month, 3 months, and 6 months and 1 year via telephone. The investigators expect the results of this observational study to influence further research into the use of frailty risk scoring prior to clinical decisions, and add to the evidence in assessing risk-related outcomes in cardiac surgery.