'Memories' of Anesthesia Lessen Heart Attack Damage

Newswise — Anesthesiologists have discovered that certain inhaled anesthetics protect heart muscle against damage. This finding now opens the door to anesthetics being considered as therapeutic agents to lessen the severity of a heart attack.

"This is fascinating because years ago, this heart-protecting anesthetic isoflurane was thought to produce ischemia (lessen the blood supply), and current research shows this is not what happens," David C. Warltier, M.D., Ph.D., professor of anesthesiology, and medicine (cardiology), senior vice chairman, department of anesthesiology, the Medical College of Wisconsin, Milwaukee, Wisconsin, said at the American Society of Anesthesiologists 2003 Annual Meeting.

Doctors have termed the process "anesthetic preconditioning" because the tissue treated by the anesthetic exposure "remembers" the treatment and continues to protect the tissue from damage from a heart attack.

For example, drugs can be taken to lower cholesterol or blood pressure, but when you stop taking them, the effect goes away. The interesting phenomenon with anesthetic preconditioning is that after the initial treatment, the effect still lasts. This is because the anesthetic has changed the tissue at an intracellular level, thus producing this cardio-protectant effect," Dr. Warltier said.

Researchers on Dr. Warltier's team have found that anesthetic preconditioning is more than an observation, and research on the subject is now focused on explaining how it works.

"This finding has the ability to have a profound impact on anesthesia, the agents used and the ramifications for all patients with coronary artery disease," Dr. Warltier said.

Research on anesthetic preconditioning was presented at the 2003 American Society of Anesthesiologists Annual Meeting Journal Symposium. The original anesthetic preconditioning work, which was conducted in a laboratory, has now been translated to patient care and has led to other research from around the world.

Researchers are also examining how this process can reduce the extent of brain injury during a stroke and kidney damage during a heart attack.

The Journal Symposium featured four speakers: Dr. Warltier, and Garrett J. Gross, Ph.D., of the Medical College of Wisconsin, two of the investigators discovering that volatile anesthetics and opioids respectively were capable of causing preconditioning; and Stefan De Hert, M.D., of the University Hospital of Antwerp, Belgium, and Michael Zaugg, M.D., of the University Hospital Zurich, Switzerland, two of the original investigators conducting not only basic research but studies in patients providing clinical evidence that volatile anesthetics are beneficial. In addition, 21 posters demonstrating anesthetic preconditioning accompanied these talks.

Dr. Warltier presented new evidence of the mechanisms involved in anesthetic protection of the heart and the impact of combining certain anesthetics with other drugs to lessen the damage caused by a heart attack.

Dr. Gross examined anesthetic preconditioning with the use of opioids such as morphine. His presentation summarized how a combination of opioids and volatile anesthetics produce remarkable effects.

Drs. De Hert and Zaugg provided evidence that volatile anesthetics have important clinical relevance and that anesthetic preconditioning might have beneficial effects on other tissues as well as a much wider variety of vital organs, such as the central nervous system. Mechanisms of preconditioning in humans were also discussed. Finally, the use of volatile anesthetics in patients with coronary artery disease undergoing noncardiac surgery was addressed.

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