The Aortic Valve (AV) is an important valve located between the heart’s left ventricle (LV) and the Aorta. When the AV is not diseased, its leaflets open fully, when the LV contracts, allowing blood to freely flow into the aorta to then supply much-needed oxygen to the entire body. When the LV relaxes, the AV closes snugly to prevent backflow of blood into the left ventricle. This mechanism works to perfection in normals – a medical marvel.
But, as our body degenerates with age, the AV can get “sclerosed” in a great number of individuals. AV “sclerosis” results in the calcification and thickening – a major geriatric problem. Of the adults aged more than 65 years, 30% exhibit “AV sclerosis”.
“Aortic valve sclerosis” is potentially harmful because it can end up making the valve flaps thickened and stiff, with subsequent narrowing of the aortic valve opening (Aortic Stenosis).
The narrowed valve, now being unable to open fully, blocks egress of blood flow from the LV and impairs oxygenation to every organ in the body. Severe symptoms could result when the impedance to blood outflow is critical. What is more, “Aortic Stenosis” (narrowing) can cause chest pain, fainting, fatigue, leg swelling and shortness of breath. In rare instances it may lead to heart failure and sudden cardiac death.
Every patient on turning 50 ought to get an “echocardiogram” to see if the AV has been affected by the sclerotic process. If so, then six-monthly echocardiograms are advised to monitor its progress. Echocardiography offers a simple, reliable and non-invasive means to detect AV stenosis and to assess the degree of “choking”.
Unfortunately, to this day, there’s no effective medical treatment (drug therapy) to reverse or arrest the progress of valve sclerosis. Once the aortic valve stenosis becomes “critical” the option is to perform “AVR” (aortic valve replacement), whereby the diseased aortic valve is replaced with a “mechanical” or “tissue valve” with “open heart surgery” through a cut (incision) in the chest.
But open heart surgery has admittedly its own risks. And the risk increases several-fold in the presence of co-morbid conditions like lung disease, cerebrovascular disease and kidney disease, when the incidence of complications may be prohibitive.
Over the last decade – I am happy to say – we saw the dawn of a new hope: “TAVR” (Transcatheter Aortic Valve replacement).
TAVR is being offered as a “minimally invasive” procedure to replace a narrowed sclerosed aortic valve. In this procedure, doctors insert a catheter in your leg and guide it to your heart delivering an “artificially-created valve” at the appropriate position. Indeed a medical breakthrough!
Minimally invasive procedures for replacing the AV until a few years ago typically targeted only patients considered “too risky” for open-heart surgery/general anesthesia. But now, there’s more good news.
The US FDA (Food and Drugs Administration) has recently given the green signal for even younger and potentially more active patients to take that route – and this is indeed wonderful news!
FDA has broadened its premarket approval for “two brands” of especially created valves to include symptomatic patients with severe native aortic stenosis who would otherwise have even a “low risk” of complications from open heart surgery.
And this welcome development has been made possible through advances in technology and better skills on the part of cardiac interventionists who through the years have refined the technique to near-perfection.
The cost of TAVR in the US runs between $54,000 and $61,000. Its cost in India is much less but still as high as INR 35 lakhs. But the majority of patients in India still opt for AVR via open-heart-surgery because its cost is relatively low to the tune of INR 3 lakhs compared to the huge cost of TAVR.
Despite the increasing popularity of transcatheter aortic valve replacement (TAVR) in the West we in India lag far behind. Only about 20,000 TAVR cases have reportedly been performed in Asia to date and the procedure is still in a nascent stage in India with very few centres confidently offering this state-of-the-art technique.
In conclusion, one can say that the idea of TAVR might have been rejected or ridiculed years ago. But, the history of medicine tells us that many examples of ideas that were initially mocked by the medical establishment later became widely adopted – these leaps flying in the face of conventional wisdom.
The age-old dictum will always hold true: “Today’s standard of care was yesterday’s experimental treatment.” Oh so true!
Further, the medical community has reason to be overjoyed that someone’s visionary idea of yesterday has at last turned into reality today.
Welcome TAVR, the medical miracle!
The agency broadened its premarket approvals of Medtronic’s Evolut and Edwards Lifesciences’ Sapien transcatheter aortic valve replacements to include symptomatic patients with severe native stenosis who would have an otherwise low risk of complications from open heart surgery, the current standard-of-care.
Medtronic says this now allows its device to be used in all surgical risk categories. The company’s clinical trial of more than 1,400 patients showed the TAVR procedure was safe and effective in low-risk patients across three device generations and was coupled with shorter hospital stays and improved quality of life.
(Dr Francisco Colaço is a seniormost consulting physician, pioneer of Echocardiography in Goa.)
