Heart Disease Deaths Prevented by Natural Back-Up System

Bypass vessels reduce risk of death in heart disease patients

(RxWiki News) Some patients naturally have a lower risk of dying from heart disease. Now researchers think they have found one of the reasons why that might be the case.

Small bypass vessels act as a back-up system for the heart's main arteries. Coronary artery disease patients with an abundance of these vessels naturally have a reduced risk of mortality.

"Exercise regularly to strengthen your bypass network."

Dr. Pascal Meier, lead author of the study, a consultant at The Heart Hospital and scientist at University College London Institute of Cardiovascular Science, said the amount of damage caused to the heart can vary greatly depending on the person in part because the back-up system is better developed in some patients. This study marks the first to show a clear difference in mortality as a result of the bypass vessels.

Dr. Meier said that an increasing amount of research indicates that these vessels are protective and can reduce mortality in patients with blocked coronary arteries. He suggested finding a means to promote the number of natural bypass vessels could help improve the outcomes for patients with heart disease.

The bypass vessels, called coronary collaterals, are tiny, specialized blood vessels that connect the larger vessels in the heart. They are basically invisible until activated, and then can enlarge their diameters to carry significant blood flow and bypass blockages.

Doctors had previously believed that the bypass vessels were not connected to coronary arteries, but newer research suggests otherwise.

During the review study, researchers compiled data from 12 studies that included 6,529 patients. They compared patient survival rates in participants with a high number of natural bypass vessels compared to those with minimal bypass vessels. They discovered that patients with lots of vessels had a 36 percent reduced mortality risk versus those with very few vessels.

Scientists did not determine why some patients have better bypass networks, but suspect it may be linked to genes and lifestyle factors.

Dr Christian Seiler, professor of cardiology at the University Hospital Bern and senior investigator of this study, noted that physical activity can improve the bypass network. He also said that some recent small studies have suggested that treatments such as external counterpulsation and injections with a growth factor may help strengthen patient's bypass networks.

The review study was recently published in European Heart Journal.

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Review Date: 
October 4, 2011