On World Heart Day 2022, Prof. Dr. G R Kane, Head of Cardiology, Kokilaben Dhirubhai Ambani Hospital explains about aortic stenosis and highlights the role of TAVR in its treatment
One of the health issues afflicting a majority of Indians nowadays are cardiovascular diseases. Out of these, aortic stenosis is one of the lesser known, but most prevalent and serious valve disease affecting the elderly with over 5-7 per cent of the population over 65 years suffering from it. It is an ailment which results in the narrowing of the aortic valve’s aperture, which leads to obstruction of blood flow from the heart into the main artery of the body. Left untreated, this disease can lead to heart failure and death. Aortic stenosis is a more common occurrence in the elderly, but can also affect younger people.
Younger populations are affected by this disease due to Bicuspid Aortic Valve which refers to a congenital abnormality where only two cusps grow in the heart instead of the normal three. Another contributing factor may also occur when the valve opening doesn’t grow along with the heart which results in the heart undergoing stress to pump blood to the restricted opening. Over time, calcium deposits in this valve lead to it becoming hard and narrow which severely harms the blood flow.1
Symptoms and progression of aortic stenosis
Many people with aortic stenosis do not exhibit symptoms until the blood flow restriction has greatly worsened or has been identified by echocardiography and the development of a heart murmur. However, there are some symptoms we can keep an eye out for which includes chest discomfort, fluttering heartbeat, breathing difficulties or breathlessness, light-headedness or fainting, short-distance walking challenges, swollen ankles or feet, trouble falling asleep or the urge to sleep upright, and diminished capacity to do daily tasks or a decline in activity level.
In addition to the symptoms, muscular thickening may also be shown on the left ventricle wall because the ventricle must work harder to pump blood through the narrow valve opening into the aorta. The thicker wall occupies more space inside the lower heart chamber, which makes it harder to supply the body with enough blood, which may lead to heart failure. The progression of this disease can be slowed or stopped with the right treatment. 2
Aortic stenosis, SAVR and TAVR
Since the early 1960s, SAVR (Surgical Aortic Valve Replacement) has been the sole effective treatment for Aortic Stenosis. A procedure which involves an incision made in the chest to access the heart, followed by the removal of the diseased valve being replaced with a new valve, it involves two different types of valves:
Metallic valves – Despite having a longer lifespan, these are not recommended for elder patients because they require lifetime oral blood thinner medications, which greatly increase the risk of bleeding and in some cases, valve clotting if the dosage is insufficient.
Bioprosthetic valves: Compared to metallic valves, these are made of bovine or porcine tissues, which are preferable in older patients since they do not require anticoagulation.
Prior to the revolutionary discovery of TAVR (Transcatheter Aortic Valve Replacement) in 2002, nobody ever thought about the possibility of replacing the valve without performing invasive surgery or creating an incision in the chest. Performed by Dr Alain Cribier in France for the very first time, TAVR has ever since been demonstrated as comparable to and in some cases better than SAVR with continued advancements in the field. With approval from the U.S. FDA in 2014, TAVR received its green signal in India in 2015-16. It has continued to change the landscape of cardiovascular treatment for minimally invasive heart procedures for high risk patients ever since.
Evolution of TAVR
The best evidence of any therapy in modern medicine comes from large-scale double-blind randomized controlled trials. Cardiologists initially compared TAVR to medical treatment in patients who the surgeons had deemed to be inoperable, demonstrating that life can be spared and its quality increased, in these critical cases.
In very high-risk surgical patients, subsequent comparison studies between TAVR and SAVR were carried out. Here again, it was discovered that TAVR was comparable to, or better than, SAVR. In addition, the studies looked at individuals with moderate surgical risk, where TAVR was likewise equivalent, and even low surgical risk patients, where the equivalence was demonstrated. However needless to say that each patient is unique and the decision to do either SAVR or TAVR is the decision made in a Heart Team meeting (Doctors meet and decide the best procedure for a particular patient).
India has seen incidences of healthcare rapidly rising across age groups. Since its inception in India, TAVR has begun replacing open heart surgeries through its minimally invasive techniques. As the burden of rheumatic and non-rheumatic Aortic Stenosis increases in India, TAVR is a beacon of hope for patients suffering from the problem. With continued advancements in the healthcare landscape in our country, we can look forward to positive evolution in TAVR as well.
References:
1 Aortic Stenosis Overview | American Heart Association
2 Aortic Stenosis Overview | American Heart Association