Coronary Arteries

The heart is located at the center of the chest, and is surrounded by the ribcage and protected by the breastbone. The heart’s main function is to keep blood continually circulating throughout the body. Arteries are the vessels that supply the body with oxygen rich blood; on the contrary the vessels that return blood to the heart are called veins. Like any other muscle in the body, the heart depends on a steady supply of oxygen rich blood. The arteries that carry this blood supply to the heart muscle are called coronary arteries. Sometimes these blood vessels can narrow or become block by deposits of fat, cholesterol and other substances collectively know as plaque. Over time plaque deposits can narrow the vessel so much that normal blood

It is important to understand that the vessels mentioned above are large, and when using these grafts on small-vessel reconstruction the graft fails. The smallest successful diameter recorded for a Dacron and PTFE grafts has been around 5mm, representing a diameter measurement too large in order for it to be used for coronary arteries, whose diameter ranges from 2-6mm. This gave action for scientists to investigate ways in which the effectiveness and potential for coronary artery replacement by altering the grafts. There are several reasons of why a synthetic graft fail in small vessels. These are, Thrombosis, Intimal hyperplasia and graft infection. Thrombosis consists of coagulation of the blood in the artery. Intimal hyperplasia is when the tunica intima of a blood vessel is thickened. Lastly is the case of graft infection, which involves patient-related, surgery related and postoperative risk factors, and can happen by direct contamination during operative procedure, in most cases from the patient’s skin or adjacent bowel. (Hydrogel and Lycra Graft) There are several ways in which Synthetic Grafts can be improved. One way is to research materials that possess non-thrombogenic surfaces. Another way is by creating grafts

Because these grafts have never been tested on humans, they have a long way to go in animal and clinical trials. These trials would prove their biocompatibility and long-term patency.

The last alternative therapy used for developing artificial arteries is called Tissue-Engineered Grafts. It is know that the ideal replacement for an artery is another artery. It will not be until 1999, when the first complete blood vessels were grown outside of the body at Massachusetts Institute of Technology. The technique consisted of obtaining smooth muscle cells from the medial layer located in the aorta of a six-month-old pig. A substantial amount of these cells were pipetted over the outer surface of a tubular scaffold, which was mainly composed of polyglycolic acid (PGA). This polymer is also known to be degradable and used in sutures. Time after the seeding period, each individual scaffold was placed in a bioreactor, also known as a growth chamber. Then, pumps were hooked up to each of the tubes. These pumps applied pulsatile radial stress, which imitated the effects of a heartbeat and encouraged the development of inward cell to grow. Endothelial cells were then taken after 8 weeks on the bioreactor, added to the inner layer and then