Previous animal studies have shown that reduced telomere length and telomerase activity in mice increases their susceptibility to ischaemia induced renal injury. The current study will look at whether a similar association is seen in humans, using cardiopulmonary bypass as a mechanism for studying ischaemia/inflammatory induced kidney injury. It aims to answer the primary research question: Are telomere length and telomerase activity related to the development of acute kidney injury following cardiac surgery? The presence of such an association would provide new avenues in the development of biomarkers to predict outcomes following cardiac surgery. In addition to scoring tools currently in clinical practice, such biomarkers might allow better risk stratification of patients undergoing cardiac surgery.