The Restoring coronary arteries with drug eluting resorbable stents compared to metal stents in patients with diffuse narrowing. The RESTORE feasibility study

The coronary arteries supply the heart muscle with oxygen rich blood. The Left Anterior Descending artery (LAD) supplies the front part of the heart muscle. Narrowing of the coronary arteries can cause angina and if one of the narrowings block off it can cause a heart attack.. Preventative medication can help to relieve or prevent these problems. When the LAD is narrowed in many places (diffusely diseased) it can often cause angina or breathlessness and medications alone may not be sufficient to treat the diseased artery. In addition to tablets coronary bypass surgery is often the best treatment when there are many narrowings, but for technical reasons it is not a suitable treatment when the LAD is diffusely diseased. It is still possible to reconstruct the artery using long stents during a coronary catheterisation procedure. Reconstruction of the artery with conventional drug eluting metal stents such as Xience can be a very effective treatment, but leaves the vessel in a permanent metal cage with risk of restenosis and stent thrombosis. The standard Xience stent is a metal stent and contains the drug everolimus to prevent the heart artery from re-narrowing. Individual case reports show that diffuse disease in the LAD may be reconstructed using bioreabsorbable scaffolds. The Absorb bioreabsorbable scaffold is made of a special type of plastic consisting of materials called polylactide polymers and copolymers. Over time these materials will gradually break down and be completely resorbed into the artery wall, leaving nothing behind and in principle restoring the natural ability of the artery to change in size in response to the needs of the heart (vasomotion). The Absorb scaffold is also coated with the drug everolimus which helps to prevent the heart artery from re-narrowing. When a narrowing in the arteries is stretched open the scaffolding effect, which prevents the artery from collapsing down again, is needed for only 3-6 months after which the artery grows larger by itself through a process called remodelling. As such the scaffolding effect from metal stent lasts much longer than needed and this can sometimes lead to problems. In theory the reabsorption of the scaffold over time may allow for future bypass grafting of the vessel if needed . While the bioreabsorbable stent seems like a good idea on many levels and initial study results are encouraging, there is much less experience with this new technology Commercial-in-Confidence and in particular whether the long term effects compared to a modern metal stent are better, worse or the same are not known. The aim of the trial is to evaluate whether, in addition to medical therapy, reconstructing the LAD with bioreabsorbable vascular scaffolds may improve outcomes versus treatment with standard Xience stents and specifically whether the artery may become suitable for coronary bypass surgery. The trial is a prospective randomised single blind, blinded end-point assessment; controlled trial