P.V.V. Murthi

Procedure using ‘chimney grafts’ successfully performed on 72-year-old

VELLORE: A team of doctors led by George Joseph, Professor and Head of the Department of Cardiology of the Christian Medical College Hospital, and comprising other cardiologists, vascular surgeons and anaesthetists, supported by critical care specialists and radiologists, successfully carried out endovascular repair of the aortic aneurysm (swelling), using three ‘chimney grafts’ on a 72-year-old patient in the hospital on September 15.

Dr. Joseph told The Hindu on Friday that endovascular repair is a less invasive technique, which was introduced 15 years ago as an alternative to open surgery, to treat aortic aneurysms, which are focal dilatations of the aorta that progressively enlarge and ultimately rupture, leading to internal bleeding and death. For the last 50 years, open surgery was the only way aortic aneurysms could be treated. Endovascular repair involved insertion of a tube-like device called ‘stent graft’ into the aorta starting above the aneurysm and ending below the aneurysm. The ‘stent graft’ allows blood to flow down its lumen but prevents blood from entering the sac of the aneurysm. As a result, the aneurysm is excluded from circulation and the risk of rupture is avoided. The blood in the aneurysm sac clots and the sac gradually shrinks.

The cardiologist said endovascular repair has lower risk than open surgery, and has been a boon to the elderly and those with co-morbidities like heart, kidney or lung disease in whom open surgery is risky.

However, endovascular repair is not feasible if there are important branches of the aorta arising close to the aneurysm, because the ‘stent graft’ would block these branches cutting off blood flow to vital organs. Thus endovascular repair is possible in less than half of all patients with aortic aneurysms.

Recent reports from Sweden and the U.S. have shown a way of carrying out endovascular repair of aneurysms even when major side branches arise close to the aneurysm. This technique involves placement of small ‘stent grafts’ called ‘chimney grafts’ in the aortic branches with their upper ends pointing upwards like a chimney. This allows the main aortic ‘stent graft’ to be deployed right across the origins of the aortic side branches without blocking them. So far, only a few such cases have been performed worldwide, and not more than two chimney grafts have been used electively in any patient (saving up to two aortic branches).

Chimney grafts

The limitation is that chimney grafts have to be introduced from the patient’s arm, and the patient has only two arms, allowing a maximum of two ‘stent grafts’ to be introduced, one from each arm.