Fat surrounding internal thoracic artery of humans produces a factor which can relax the artery

A team of McMaster researchers has discovered that fat tissue surrounding thoracic arteries may be beneficial in patients undergoing coronary bypass surgery.

A study led by Yu-Jing Gao, of the Department of Anesthesia, found that fat surrounding internal thoracic arteries produces a factor that can relax the artery. That finding could lead to an answer to one of the challenges that cardiac surgeons face during coronary artery bypass grafting (CABG) surgery.

A report on the study was published in the October edition of The Journal of Thoracic and Cardiovascular Surgery.

Dr. Robert Lee, also of the Department of Anesthesia and a researcher who worked on the study, explained that arteries used for grafting will contract during surgery, making it more difficult for the surgeon performing the procedure, and restricting blood flow in the artery following the surgery.

Drugs are often used to prevent the contraction, but a study published two years ago showed that one of the drugs most commonly used for that purpose could cause cellular damage to the blood vessel. That finding created the need to look for alternative methods for keeping the grafted artery relaxed during and after surgery.

"We have demonstrated for the first time that fat surrounding the internal thoracic artery of humans produces a factor which can relax the artery," said Lee. "This is potentially important, because retaining the fat tissue surrounding these artery grafts during CABG, may help alleviate or prevent artery contraction."

During CABG, surgeons usually remove the fat tissue surrounding the artery they are using for grafting, to give them access to more of the artery surface and making the procedure easier to perform.

Dr. Lee said the next step will be to determine if clinical evidence shows that leaving the fat tissue intact during CABG surgery provides for better blood flow than is shown by patients in which the fat tissue is removed.

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