Restricting arm’s blood flow may protect the heart

Patients undergoing coronary artery bypass surgery may have improved outcomes by first having a procedure that temporarily restricts the blood flow in their arm, a study hints. So called “remote ischemic preconditioning” may reduce the heart damage that occurs during heart bypass surgery, cardiologists report in Friday’s edition of The Lancet.

Remote ischemic preconditioning works by depriving one tissue of blood flow in hopes of protecting another organ from sustained ischemia (reduced blood flow). Whether this technique actually benefits people undergoing CABG, however, is unclear.

Dr. Derek M. Yellon, from University College London Hospital, and colleagues studied 57 patients undergoing heart bypass surgery. Of these, 27 received remote ischemic preconditioning - namely, three five-minute cycles of having the blood flow in one arm restricted using an automated cuff-inflator. There was a five-minute period between each cycle where the cuff was deflated. The other 30 patients served as controls.

Remote ischemic preconditioning was associated with a significant 43 percent reduction in troponin T levels after bypass surgery, the investigators report. Troponin T is a heart-related protein that may be released into the bloodstream following the “injury” to the heart during surgery. The presence of troponin T in blood in bypass surgery patients is associated with poor outcomes after surgery.

SOURCE: The Lancet, August 18, 2007.

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