The Cardiac Revolution
Cardiology “A new technique to deliver aortic valve replacements could be the single most important step in cardiac innovation ever undertaken,” says leading cardiologist, Dr Michael Mahmoudi, Clinical Senior Lecturer In Cardiological Science at the University of Surrey.
According to Dr Mahmoudi, the development of a technique know as transcatheter aortic valve implantation (TAVI) is set to change the way aortic stenosis, which occurs when the aortic valve becomes narrowed and obstructs the blood flowing through it, is treated.
At present aortic valve replacement, performed through open-heart surgery, is performed on about 5,000 individuals each year. The process involves cutting the chest of a patient to access the heart. The heart is then stopped and a heart-lung bypass machine is used to take over the circulation during the operation. The aortic valve is removed and replaced with either a tissue or a metal valve. The heart is then started again and the chest incision is closed.
Whilst the procedure is very effective, patients generally remain in hospital for five to six days after surgery and won’t feel the full benefits of the replacement for up to three to six months. Those who have a metal rather than a tissue valve inserted will also need to take blood-thinning drugs, such as Warfarin, indefinitely.
Perhaps most notably, there are a large proportion of people who need an aortic valve replacement, but for whom the current procedure is too dangerous. This includes the very elderly, those with pre-existing conditions, such as diabetes or renal failure, anyone who has suffered a stroke or those who have had major surgery.
With TAVI, the risks are greatly reduced giving more people the opportunity to access the life saving procedure. “The process is much less intrusive,” explains Dr Mahmoudi. “Instead of open heart surgery, the new valve is guided into place using a catheter that is inserted into the femoral artery through the groin.”
TAVI can be carried out using mild anaesthesia known as conscious sedation. The patient will only be required to stay in hospital for around three to four days and within a week they should feel the benefit of the new valve. With greater accessibility, fewer risks, a quicker recovery time and lower costs for the NHS, the benefits are immediately evident.
The first randomized controlled trial of TAVI was published in 2011, so data is limited to the last five years. However, as Dr Mahmoudi explains, “there have been a number of major studies all showing positive results and the longevity of the valve replacement. We’ll continue to monitor patients, but within the next five to 10 years, TAVI could be the standard procedure for aortic valve replacement.”
Dr Mahmoudi leads research for the Ashford and St Peter’s NHS Foundation Trust in collaboration with Surrey University and the Trust Research Department.