Health Education – The Heart of the Matter
The Heart of the Matter – Replacing aortic valves to give hearts a new lease of life
By Dr Paul Chiam
Published on Ezyhealth on May 2015
The aortic valve allows blood to be pumped out of the heart to the rest of the body. With ageing, the aortic valve may become narrowed. This is known as aortic valve stenosis (AS). When the valve narrowing becomes severe, patients develop breathlessness, fainting spells and chest discomfort. Left untreated, the death rate is high, with up to 50% of patients dying from the condition within two years.
Open heart surgery to replace the aortic valve is the conventional method of treating this disease, relieving patients of their symptoms and prolonging their lifespan. However, for many elderly patients and for those with multiple co-existing illnesses, the surgical risk for open heart surgery is high, and some patients are even considered inoperable.
A new technology is being used to “replace” the aortic valve non-invasively, without the need for rib cracking or stopping the heart – Transcatheter Aortic Valve Replacement or Implantation (TAVR/ TAVI). The procedure is performed mostly via a small puncture in the groin, although in a
small number of patients, other access sites are required (via the subclavian artery in the chest, via the aorta directly or through a 5 – 6 cm incision in the left chest wall). The groin approach is the least invasive and thus preferred.
More than 140000 patients worldwide have undergone this procedure using two transcatheter heart valves (a transcatheter heart valve is a stent with a new valve sutured within the frame): the Sapien XT transcatheter heart valve made by Edwards Lifesciences and the CoreValve made by Medtronic. Studies have shown that TAVR was superior to (better than) medical therapy in patients with severe AS who were inoperable, and was non-inferior (equal) or superior to (better than) open heart AVR in patients at high surgical risk.
Better Than Before
Up till recently, however, the transcatheter heart valves, though safe and effective, could not be repositioned or recaptured if they were implanted in a position that was less than optimal. In effect, the surgical team had “one chance” to optimally insert the valve.
In January 2015, two repositionable and recapturable valves became available in Asia – the Medtronic CoreValve Evolut R and the Boston Lotus valves.
These new generation transcatheter heart valves can be recaptured and repositioned if the initial implant position is deemed too high or too low, and can even be removed from the body if a smaller or larger sized valve is required. These features increase the accuracy and safety of the procedure.
In addition, the Boston Lotus valve has an external “skirt” which is an additional feature to reduce leakage between the newly implanted transcatheter heart valve and the patient’s native tissue. Such leaks between the new valve and the patient’s tissue have been shown to impair long term survival – thus, the lesser the amount of such leaks, the better the longer term outcome for the patient. Other valves are also being modified to include this external “skirt” feature.
Our team at Mount Elizabeth Hospital successfully performed TAVI/TAVR in two patients in January – using the CoreValve Evolut R and the Boston Lotus valves – under local anaesthesia and sedation, via an access in the groin.
These new generation valves are indeed a game changer and will offer many patients with severe AS not only an alternative treatment with TAVR/TAVI, but also a more accurate and safer TAVR/TAVI procedure.