Improving the success of bypass surgery

---

Coronary heart disease (CHD) involves the narrowing of blood vessels around the heart. If these vessels become blocked it can lead to a heart attack. One of the current treatments for heart disease is a coronary artery bypass graft (CABG). In a CABG, a grafted blood vessel taken from somewhere else in the body, often the leg, is used to bypass the blocked artery and restore blood flow to the heart.

However, the grafted blood vessel itself often becomes blocked, known as vein graft failure. It is thought that this may be due to the fact that the blood vessels used as the grafts are not suited to the blood flow that occurs near the heart, as this blood flow has a higher pressure than in the arms or legs. In particular, the blood vessels used as grafts may not be able to expand and stretch the way that the original blood vessels do, which exposes them to a high level of pressure, and can cause the graft to fail.

This project, led by Dr Denise McDonald, aimed to explore potential ways of improving the function of these grafted, replacement blood vessels. The team explored the connection between a chemical compound, called nitric oxide (NO), and a chemical pathway called NOTCH, which control a blood vessel’s ability to respond to the pressure of blood flow correctly.

They were able to identify a potential target for treatment within the NOTCH pathway that could allow the grafted blood vessels to behave in a more similar way to the original blood vessels around the heart. The next stage for their research is to explore methods of using this target to improve the function of grafted blood vessels. If they can successfully help prevent these vein grafts from failing, it will significantly improve the outcomes for CABG procedures. This will mean increased quality of life after the procedure, as well as improving the chances of long-term survival.