Transcatheter Aortic Valve Replacement (TAVR) is a well-proven procedure for aortic valve replacement in people who are considered as high-risk patients for open heart surgery. In this procedure, a new aortic valve is fixed without removing the old and damaged valve with the help of a specialised catheter through a process similar to stenting. A new artificial valve wedges into the place of the older aortic valve.
A comprehensive evaluation is done to determine whether this procedure is an appropriate treatment option for the patient or not. This includes clinical examination, echocardiogram, CT scan and cardiac catheterisation.
Aortic Stenosis (AS) is one of the most common and serious valve diseases. In this, a heart valve situated at the gateway between the main pumping chamber of the heart (left ventricle) and the big blood vessel (aorta) that supplies blood to the whole body becomes thick, calcified and narrowed. The heart chamber has to work harder against the narrowed, diseased valve and ultimately starts failing.
The common causes of this disease are old age, rheumatic infections or a structurally malformed valve present from birth which starts degenerating by the fourth or the fifth decade of life. These all result in calcification and scarring of the valve leading to restriction in its opening. The treatment constitutes of replacing the diseased aortic valve with a new valve either through an open heart surgery or TAVR, a catheter-based non-surgical technique.
It is important to note that many people with Aortic Stenosis do not experience noticeable symptoms until the amount of restricted blood flow becomes significantly reduced.
Symptoms of AS may include breathlessness, chest pain, pressure or tightness, fainting (also called syncope), decline in activity level or reduced ability to do normal activities requiring mild exertion. Even sudden death can occur or the heart may gradually fail.
Somewhat similar to stent placement in an artery, the TAVR approach delivers a fully collapsible replacement valve to the original valve site through a specialised tube-based delivery system (catheter). It is done via a small puncture in the groin, entering through the femoral artery (large artery in the groin), and usually does not require any major cut.
The valve is taken through the specialised delivery catheter to the site of the original valve and is deployed there. Once the new valve expands, it pushes the old valve leaflets out of the way and the tissue in the replacement valve take over the job of regulating blood flow. The small puncture in the groin is finally sealed.
It is a minimally invasive interventional (non-surgical) technique performed in a cath lab, like angioplasty. It does not require the chest to be opened and has low hazards and risks of long hours of general anaesthesia as needed in the case of open heart surgery. There is no big scar and the puncture site is sealed off at the end of the procedure. It can even be performed in an awake condition under mild sedation.
The hospitalisation period is just three to four days and the stay in ICU is just a night for monitoring and recovery after the procedure is done. The person can return to normal life activities soon after being discharged from the hospital.
It has a lower risk even for patients who have multiple serious medical or surgical conditions as discussed, which make them a risk or unfit for open heart surgery. A small percentage of patients may require permanent pacemaker implantation, which is similar to open heart surgical valve replacement.
As of now, the procedure is reserved for the elderly for whom an open heart surgical procedure is a high risk or intermediate due to medical and surgical conditions such as previous heart surgery, severe lung disease, diabetes, kidney failure, oxygen dependency at home and severely calcified aorta (Porcelain Aorta).
A person whose previous artificial bio-prosthetic aortic valve is degenerated can also obtain a new valve through this technique without redoing open heart surgery. Although relatively new, TAVR is an effective option to treat and improve survival and quality of life in these patients. It is an established and well-proven treatment for severe aortic stenosis.
(The writer is Consultant Interventional Cardiology, Fortis Hospital, Cunningham Road)