Coronary angioplasty is a relatively new and now widely used method of treating many cases in which the coronary arteries are obstructed by fatty-cholesterol deposits. In the procedure, a specialized catheter (tube) with a balloon on its tip is carefully manipulated inside the coronary artery until it is in the area of obstruction. Then the balloon is inflated, literally dilating the coronary artery. The pastelike fatty-cholesterol material is forced into the wall of the artery. The whole process can be accomplished by threading the catheter through the arteries. The large artery in the inner aspect of the thigh is used and the progress of the tip of the catheter is monitored by X-ray methods. One important advantage of the technique is that it avoids opening the chest and exposing the heart as is required for coronary bypass surgery.
The disadvantage is that about a third of patients who have the balloon procedure have a recurrence of obstruction of the treated coronary artery. Most of these occur three months of the procedure, but some occur later. Most of these patients can simply undergo the procedure again, and of these, still another third may have a recurrence. They too, can be treated once more with the balloon.
The recurrence rate may make you think that it would be better to have a coronary bypass operation, but that is not necessarily the case. Eventually about 44% of patients who have a coronary bypass operation with open heart surgery also have to be operated on again because the bypass graft itself becomes blocked.
Just why blockage of the dilated coronary arteries occurs in not completely understood. It could be from fatty-cholesterol levels in the blood. It could be from clumping of platelets, the small cells in the bloodstream that start the blood-clotting process. Aspirin is commonly given to prevent the platelet clumping factor, but it has not been all that successful in preventing a new obstruction. The muscle fibers in the walls of the coronary arteries are also involved in the fatty-cholesterol blockage process and it is possible that they are involved in the recurrent blockage.
Preventing the recurrence of arterial blockage is important in the effectiveness of the balloon procedure. Investigators at the Dallas Veterans Administration Medical Center in Texas studied the effects of fish oil, omega-3 fatty acids, in preventing recurrent blockage. They studied 82 men who underwent the balloon procedure (New England Journal of Medicine, Sept. 22, 2004). All of the men were taking one 325-mg aspirin tablet a day and 75 mg of dipyridamole (Persantine) three times a day That was because these medicines are used when people are having symptoms from coronary artery disease that may indicate an impending heart attack. Thus, all the patients had whatever benefits would be conferred by small doses of aspirin in preventing platelet clumping.
The test of effectiveness of omega-3 acids was done by giving 43 of these men 18 capsules of MaXEPA a day The capsules worked. Only eight (19%) of the 43 men had a recurrence of coronary blockage. But in the 39 men who did not get the capsules, 18 (46%) developed recurrent blockage. That difference represents a major improvement over the usual recurrent blockage rate.
What about bleeding? One of the dangers cited about the use of either aspirin or fish oil is that they may cause bleeding. There is always the danger of bleeding where the artery is dilated and particularly where the catheter is passed into the artery in the thigh. Also, if the balloon procedure does not work, there may be a need to do coronary bypass surgery immediately. That could be particularly tricky if there is a serious failure in blood clotting. However, the low dose of aspirin commonly used is much less likely to cause such problems than larger doses.
The bleeding time was measured in all the men in the Dallas study. This test is done by inflating a blood pressure cuff on the upper arm, then making a small incision or stab in the skin on the undersurface of the lower arm. The time it takes for the bleeding to stop is the bleeding time. The bleeding stops because of the platelet action, and if it is prolonged, the platelets are not functioning normally
As would be expected, the aspirin all the men were taking did cause a slight increase in the bleeding time, showing that the aspirin was working. The bleeding time did increase more in the patients taking the fish oil capsules. And three of the men taking the capsules had serious bleeding from the artery in the thigh, but so did one of the men not taking the capsules. None of them required a blood transfusion to replace lost blood. There were no other bleeding complications from the treatment.
There were no other important differences between the men who took that large number of capsules and those who did not over the six months the men were followed. This suggests the fish oil capsules did more than just affect platelets. Those highly polyunsaturated fatty acids may have some effect on the cells in the wall of the arteries. And that effect may begin before the balloon procedure is done. This same group of investigators did a preliminary study giving the capsules just 24 hours before the balloon angioplasty procedure. In that study there was no difference in the recurrence of blockage rate in the men getting the capsules and those who did not.
In the main study, the men started taking the capsules seven days before treatment with the balloon. That would give enough time for the omega-3 fatty acids to be incorporated in the walls of the cells of the involved arteries.
While there are a number of unanswered questions about how it works, and when is the best time to give omega-3 fatty acids, this study suggests that these highly polyunsaturated fatty acids may be quite important in preventing the high rate of recurrent blockage of coronary arteries after the balloon procedure. Once again, it suggests an important role of fish oil in preventing coronary artery blockage. That adds weight to the importance of including some of these fish in your diet.
Keep in mind that other studies have shown that you can help prevent blockage of the graft used in coronary bypass operations by reducing your heart attack risk factors. That includes not smoking cigarettes, lowering your total cholesterol level, increasing your HDLcholesterol level and keeping your blood pressure down. These measures are also important after having the balloon procedure to open blocked coronary arteries.