What are Nature’ Bypasses?

A friend wrote the other day and asked “What are nature’s bypasses?”  One of her male relatives began having chest pain and subsequently had a heart angiogram (heart catheterization) which showed an 80% narrowing of one artery and a second artery completely blocked near its origin from the aorta.  He had had a previous heart attack years before.  The heart cath showed the artery beyond this total blockage was being filled with blood from one of the other coronary arteries.  Normally blood in an artery passes through capillaries into the veins, but this was a direct artery-to-artery connection.  Direct artery to artery connections are rarely present anywhere else in the body.   The medical term for this finding is “collateral blood flow” and illustrates nature’s attempt to overcome the total blockage and thus reduce heart muscle damage.  Nature does amazing things. 

In reality this is what we do when we insert vein bypass grafts from the aorta to a  coronary artery beyond such blockages.  Vein bypass grafts carry a large amount of blood whereas collateral channels carry a relatively small amount of blood.  Never the less these collateral channels are important in helping heart muscle to survive, reducing the size of heart attacks.  Heart attack patients need all the help they can get and we all want as many collateral channels as possible.  These channels may be the difference, as in the case above, in determining whether we survive a heart attack or not.

Summary:  Nature’s bypasses are collateral artery channels that connect one coronary artery directly with another when one of the arteries is totally obstructed.  This is nature’s attempt to overcome obstructed coronary blood flow and reduce heart muscle damage when the patient suffers a heart attack.  There is nothing the patient can do to develop these channels other than to remain physically fit and active and follow preventive measures to avoid coronary heart disease.