Affairs of the heart: not all stents are created equal

Santosh Prabhu is a quintessential Mumbai boy, having grown up in Chembur and graduated in aerospace engineering from IIT, Bombay. Having lost his father to heart attack, Prabhu is passionate about matters of the heart, or in his parlance, coronary heart disease.  

For over 15 years Prabhu is involved and has seen “the evolution of the family of stents,” from bare-metal types to drug-eluting ones (coated with a medicine) to the breakthrough stents that dissolve in the body.

A stent is a thin wire-like mesh inserted into a blood vessel to open up blockages, especially in the heart, as it could otherwise lead to complications including heart attacks. This medical device, though, is at the heart of a price-debate in India, as the Government grapples with stents, the technology involved in developing it and the price it should command.   

 “Not all stents are created equal,” says Prabhu, Director of research and development at Abbott Vascular Structural Heart. There is planning and research that goes into its clinical evolution, he says, and cost is just one factor.  Giving an inside view on some of the factors that go into developing a stent, the scientist-engineer explains, you need the right metal for the stent that also lends itself to manufacturing at a later date.

It’s not just about how a stent is “cut”, he says, busting popular perception. Its mechanical performance is critical, as it needs to be thin to enter an artery and yet strong to keep the walls of a blood vessel open to prevent repeat blockages. “Cutting” the stent is just one of many steps, and is preceded by a comprehensive design process, he adds.

 In drug-coated stents, the search is for the right drug to co-habit with the metal inside the body. They are marketed after extensive clinical trials (where the stent is tested on humans). Follow- ups continue with patients for years after it has been used in them, he explains.

 There cannot be a single goalpost to assess a stent, he indicates, given the variables around the condition when it is used - including the natural progression of the heart disease.

 A key indicator is if the stent can deliver in an acute situation, he says. Can it withstand the lifetime cardiac motion of a beating heart? Or does it work in a small-made person, for example.

 The Indian regulator requires stent-makers to at least have a CE mark or approval from European regulatory authorities. Explaining how it differs from the United States Food and Drug Administration’s approval, Prabhu says, CE involves tests on a smaller number of patients compared to the USFDA. The USFDA also compares new tech to existing standards of care, he adds.

 While price-sensitive markets continue with a bouquet of stents, with bare metal ones costing less than a drug-eluting one or the absorbable one, he stresses, the bottomline has to be its clinical results.  You don’t want to make a compromise on clinical data, he says, emphatically. (Stents are priced between ₹25,000 to a couple of lakhs in India.)

 So have stents reached the end of their evolution story? Not quite, indicates Prabhu, as work continues on next-gen stents that work more efficiently, but are still under wraps. 

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