Therapy Offers Alternative to Bypass Surgery

An experimental treatment that encourages new blood vessels to grow in the heart may benefit people who are not good candidates for bypass surgery, researchers report.

An experimental treatment that encourages new blood vessels to grow in the heart may benefit people who are not good candidates for bypass surgery, researchers report.

When a heart artery becomes blocked, one way to keep blood flowing to the heart is to bypass the clogged vessel with a vein or artery taken from another part of the body. In some cases, however, it is impossible to bypass all blocked vessels, either because heart disease is too severe or the vessels are too small.

A team of researchers led by Dr. Michael Simons, of Harvard Medical School in Boston, Massachusetts, found that a protein called a growth factor can restore blood flow to the heart and relieve the crushing chest pain called angina. The protein works by triggering the growth of new blood vessels that bypass the blocked ones.

The investigators studied 24 patients with heart disease who had some arteries that could be bypassed and some that could not. During surgery, one of three kinds of capsules was placed next the arteries that could not be bypassed: a capsule containing a high dose of growth factor; a capsule containing a low dose; or a placebo -- a capsule that did not contain any growth factor.

Several measurements showed that treatment with the high-dose capsules successfully restored blood flow in the heart, Simons and colleagues report in the November 2nd issue of Circulation: Journal of the American Heart Association.

First, an average of 16 months after having the surgery, none of the patients who received the high dose had angina, which can occur when the heart does not receive enough blood. In contrast, three patients in the placebo group and one in the low-dose group had angina.

Second, within 3 months after surgery, blood flow in the heart improved significantly in patients who received a high dose of the growth factor. Blood flow did not change in the low-dose group and it decreased in the placebo group, according to the report.

Finally, the percentage of the heart that did not receive enough blood dropped significantly more in people who received growth factor than in those who received the placebo.

In addition, the therapy appeared to be safe, since it did not cause any more serious side effects than the placebo caused.

This preliminary study is the type of proof needed before moving on to larger studies, which are now under way, Simons told Reuters Health in an interview.

While the treatment is being studied in people who are not good candidates for bypass surgery, it may eventually be used instead of bypass surgery in some people, Simons predicted.

SOURCE: Circulation: Journal of the American Heart Association 1999;100:1865-1871.