Omega 3 (Fish Oil) Protects Heart after Bypass Surgery

Healthnotes Newswire (August 25, 2005)—Taking fish oil before a coronary artery bypass might reduce the damage to heart cells caused by the surgery, according to Prostaglandins, Leukotrienes, and Essential Fatty Acids (2005;72:257–65).

Coronary artery bypass surgery is a major heart surgery performed to improve blood flow to the heart muscle. In order to perform the operation, the surgeons must temporarily block the flow of blood to the heart; following the surgery, blood is allowed to flow again. The period during which blood flow through the coronary arteries is restored, known as reperfusion, is an especially vulnerable period; during that time the heart muscle is susceptible to injury. How reperfusion causes injury to the heart is not clearly understood, but it is believed that both inflammation and oxygen free radicals play a role.

The oils from fatty fish, such as salmon, cod, herring, and tuna, are rich in anti-inflammatory omega-3 fatty acids. Studies have found that fish oil from both diet and supplements has a number of beneficial effects on the heart and the risk of heart disease: it can reduce total cholesterol, LDL (“bad”) cholesterol, and triglyceride levels; increase HDL (“good”) cholesterol levels; lower blood pressure; prevent abnormal heart rhythms; and prevent heart attacks and sudden cardiac death.

In the current study, 40 people scheduled to undergo coronary artery bypass surgery were randomly assigned to take either 8 grams of fish oil per day or a placebo for six weeks prior to surgery. Blood was drawn at the beginning of the study, one day before surgery, and after reperfusion. These blood samples were used to measure levels of chemicals associated with inflammation. Blood was also taken immediately after surgery and at various intervals up to 120 hours thereafter to measure levels of a chemical associated with heart muscle cell damage.

The degree of inflammation was not significantly different between the two groups at any point in the study. Levels of the chemical marker of heart damage rose similarly in the two groups after surgery; however, at 24 hours after surgery, the level of this chemical dropped in the fish oil group but continued to rise in the placebo group, indicating that the period during which reperfusion injury occurred was shorter in the group using fish oil. Blood loss during surgery was measured and found to be slightly greater in the fish oil group than the placebo group, but this difference did not reach statistical significance.

The results of this study suggest that fish oil supplements might prevent some of the reperfusion injury that occurs after coronary artery bypass surgery. They further suggest that this protective effect is not due to the anti-inflammatory properties of fish oil. Despite concerns about the anti-clotting effects of fish oil on blood loss during surgery, excessive blood loss due to fish oil was not observed in this study. Additional studies are needed to determine whether the presurgical use of fish oil can improve the long-term cardiac health of people who have had coronary artery bypass surgery.