Reducing vein graft failure following heart bypass surgery
Translational Research Project Grant – Prof Sarah George, University of Bristol
Heart attacks are usually caused by blockage of the coronary arteries supplying blood to the heart muscle. One of the treatments for blocked coronary arteries is heart bypass surgery using sections of vein from the patient’s leg to bypass the blockage. Unfortunately, these vein grafts suffer from unacceptably high failure rates, with approximately 50 per cent failing within ten years. This means that some patients will go on to experience recurrent angina or heart attacks, and need further operations.
Vein graft failure is caused by increased activity of cells within the vein graft which causes thickening of the inner layer of the vein. Professor George’s team has been studying a protein that plays an important part in ‘cell adhesion’ – the binding of cells to one another. They have shown that the ‘adhesion protein’ reduces over-activity of cells within the vein and graft thickening, without harmful effects on the blood vessel wall. They have also found that a very small part of the adhesion protein can act as a mimic for the full-length version and has similar effects on the vein graft.
They will package the mimic in small biodegradable spheres called ‘microspheres’ to deliver the mimic in a continuous way. The microspheres may prolong release and therefore could be used in patients to slowly deliver the mimic to the vein graft. By studying human veins that are used for bypass surgery they will test whether microspheres can improve delivery of the mimic and reduce graft thickening.
If the mimic reduces over-activity of the cells within the vein graft without adverse effects on the blood vessel wall, it may have potential as a treatment to prevent vein graft failure following bypass surgery. If successful, it could be used to improve the outcome of heart bypass surgery and reduce the need for surgery to be repeated.