Researchers believe that coronary artery bypass graft surgery outcome may be improved if the blood supply to a patient’s arm is restricted temporarily. You can read about this in an article in this week’s issue of The Lancet, accompanied by a Comment which explains that the implications for this clinical practice are immense.
Professor Derek Yellon, The Hatter Cardiovascular Institute, University College London, and team observed 57 patients who underwent elective coronary artery bypass graft surgery. 27 of them received remote ischemic preconditioning – three to five minute cycles of having the blood flow in one arm restricted using an automated cuff-inflator, with five-minute period between each cycle when the cuff was deflated. They were compared to a control group of thirty patients. All 57 had amounts of troponin T in their blood measured prior to surgery, and then six, twelve, twenty-four, forty-eight and seventy-two hours after surgery. When there is damage to the heart during surgery troponin T, a cardiac protein, can be released into the bloodstream. Short and long term outcomes following surgery are closely linked to release levels of such proteins.
After 72 hours the researchers found that total troponin T released by the control group was 36.12 μg/l, compared to 20.58 μg/l in the remote ischemic preconditioning group; 43% less.
“Our study has shown that remote ischaemic preconditioning, mediated by transient upper limb ischaemia, can reduce troponin T in the perioperative period in adult patients undergoing elective coronary artery bypass graft surgery…One might expect that in high-risk patients for whom serum troponin T concentrations are substantially greater, remote ischaemic preconditioning might confer an even greater reduction in myocardial injury,” wrote the authors.
“Clearly the technique for remote ischaemic preconditioning needs to be duplicated by equally skilled workers in other cardiac centres in large numbers of patients. In the meantime, if intermittent limb occlusions are consistently shown to reduce myocardial injury during cardiac revascularisation, the implications for practice are immense,” Dr Henry Purcell and Professor John Pepper, Royal Brompton Hospital, London, UK wrote In the accompanying Comment.
Written by: Christian Nordqvist