Ultradian rhythms of cortisol after cardiac surgery


Sponsor: University of Bristol

REC Number: 11/H0107/9

Status: Closed to recruitment

Heart surgery provokes a large stress response in the body, which can lead to complications after surgery.  Cortisol is the main hormone responsible for the stress response, but currently researchers do not know how heart surgery affects cortisol production and whether steroids can be given in a more tailored way.

The Cortisol study is examining whether heart surgery disrupts the diurnal rhythm of cortisol production, which normally causes cortisol to increase early in the morning and dip by late afternoon.  This rhythm is produced by discreet pulses and researchers believe that disrupting these pulses increases the stress response after surgery.

We are recruiting men undergoing a coronary artery bypass grafting (CABG) operation to investigate cortisol pulses after surgery.  Women are not being recruited due to the cyclical effects of female hormones on these rhythms. We are also investigating whether the use of the bypass machine during heart surgery influences cortisol production. For this initial part of the study, we allocated a group of similar patients by chance to receive surgery with a bypass machine or surgery without a bypass machine.

Contact Information

Chief Investigator: Dr Ben Gibbison