Ischemic Preconditioning Before CABG Surgery Improves Outcomes

A new study suggests that coronary artery bypass graft (CABG) surgery outcome may be improved if the blood supply to a patient's arm is restricted temporarily.

Researchers at University College London (UCL; UK) conducted a single-blinded randomized controlled study of 57 patients who underwent elective CABG surgery. Twenty-seven 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 30 patients. All 57 had amounts of troponin T in their blood measured prior to surgery, and then six, 12, 24, 48, and 72 hours after surgery.

The researchers found that after 72 hours 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, signifying a reduction of 43% in troponin T levels. The study was published in the August 18, 2007, issue of The Lancet.

"Our study has shown that remote ischemic preconditioning, mediated by transient upper limb ischemia, can reduce troponin T in the perioperative period in adult patients undergoing elective coronary artery bypass graft surgery,” said lead author professor of cellular cardiology Derek Yellon Ph.D., D.Sc., and colleagues. "One might expect that in high-risk patients for whom serum troponin T concentrations are substantially greater, remote ischemic preconditioning might confer an even greater reduction in myocardial injury.”

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.


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