2 The condition, current treatments and procedure
2.1 Marfan syndrome is a genetic disorder of the connective tissues. One effect of it is that the wall of the aorta can weaken and progressively widen. The wall can tear (dissection) and possibly rupture, which is often fatal. The strongest predictors of dissection are the aortic root size and the rate of change in size over time.
2.2 Conventional treatment involves pre-emptive surgery to replace the ascending aorta with an artificial fabric graft. Some clinicians recommend this when the aortic diameter is 45 mm or more. The aortic valve is also usually replaced but may be conserved. People can experience considerable anxiety waiting for their aorta to reach the size threshold recommended for surgery.
2.3 If the person has a mechanical valve implanted, they need lifelong anticoagulation. If a bioprosthetic valve is used, it is likely to eventually fail, and the person will need another operation. Valve‑sparing root replacement surgery, in which the aorta is replaced with a tube graft and the native aortic valve is conserved, is also suitable for some people with normal valve function. This is technically more challenging, and people may need further surgery to replace the aortic valve at a later date.
2.4 The aim of personalised external aortic root support (PEARS) using mesh in people with Marfan syndrome is to reinforce the aortic root and ascending aorta to prevent enlargement and subsequent dissection or rupture. The native aortic valve is left intact so there is no need for lifelong anticoagulation after the procedure. This is a particular advantage for young women considering future conception. Cardiopulmonary bypass is usually not needed, and the operative time is shorter than for traditional aortic root replacement.
2.5 The first step of the procedure is to do imaging studies of the ascending aorta and aortic root. Computer-aided design is used to create a 3‑dimensional model of the aorta, which is then used to make a bespoke external polymer mesh support. The mesh is soft, flexible and porous. Openings for the coronary arteries are fashioned into the mesh support.
2.6 Under general anaesthesia, a median sternotomy is done, and the aorta is dissected away from adjacent structures and proximal to the coronary arteries. The mesh support is passed behind the aorta, sutured up the front and secured to the aortoventricular junction. It fully encircles the aortic root and extends from the region of the valve annulus to the origin of the brachiocephalic artery.