The Story of Stent

Today is my 17th re-birthday. If you’ve been a longtime reader, you know why I call it my re-birthday. If you are new around here, well, here is a short recap. Just after I turned 41—17 years ago—a life of poor habits and family genetics caught up with me. I had a heart attack and was in the hospital for a few days. The doctors discovered all sorts of problems, and I ended up on the operating table. I came back home with a few new additions to my heart—the stent.

This morning, over my first cup of tea, I started to think about the past few years – things that have gone right – mostly right – since that heart attack. It was a terrible situation, but it changed the trajectory of my life.

After the surgery, the doctors told me to shape up. So in the years that have gone by, I’ve become obsessed with kicking all my bad habits. No red meat, no alcohol, and most importantly, no smoking. I quit smoking cold turkey 17 years ago. It was not an easy thing, but I am glad I did. At the time, the doctors told me I was type 2 diabetic, so I needed to get my diet under control. In short, with medication and major lifestyle changes, doctors said that I could improve my health.

Over the past 17 years, I have kept notes. I try to eat well, walk, and avoid everything that is not good for me – with an occasional exception. I am first to volunteer for new treatments. It is not that I want to live forever, it is just that I want to enjoy life I have – whether it is a day, a decade, or three. Either way, I want to give myself the best chance of doing that.

Lost in my reverie, I realized that one thing I had not thought about even once was the actual technology that set me on the right trajectory – the stent. It is ironic because both as a reporter and as an investor, my first instinct is learning about the who, why, and what of technology. And yet I never took the time to really learn about how a “stent” works, its origin, and how the technology has progressed since December 28, 2007.

All technologies come with obsolescence, and my doctors have consistently told me to be prepared for a day when I might need a retrofit. My lifestyle has changed but my genetics have not. South Asians as a group are most prone to cardiac diseases. I wanted to find out how far stents have come over the past decade and a half.

How much have they improved, should I need a new one? I have done the same for my diabetes and blood pressure. If I can obsess over an iPhone upgrade, it is prudent to know more about the latest in stent technology. So, off I went. And before I knew it, it was midday. The more I learned about the stent, the more fascinated I was by its history, its journey, its impact on society, and of course its future.

Just like the stent, another technology entered my life in 2007: the iPhone. I couldn’t help but think of coronary stents — one of medicine’s most significant technological advances — as akin to the revolutionary impact of the iPhone on consumer technology. It was a weird coincidence, but in a way, using the smartphone as a parable would be a good way to tell the story of the stent.

No, I am not saying they are the same thing – they are not even remotely the same – however, they have had an impact on society and have turned companies into financial giants. American Heart Association data shows that cardiovascular diseases accounted for 19.91 million deaths in 2021, making them the leading cause of death globally. Coronary artery disease (CAD) accounted for approximately 8.9 million deaths worldwide in 2015, representing 15.6% of all deaths. I use these numbers — dated as they might be — to underscore the importance of this technology. As someone who has benefited from it, I can’t overstate its significance.

The impact on heart disease treatment has been profound. Before stents, patients often faced open-heart bypass surgery as their only option. Today, over 2 million people annually receive stents in procedures that typically have patients home the next day. For companies like Abbott, Medtronic, and Boston Scientific, stents generate billions in annual revenue while driving continuous innovation toward “smarter” and eventually dissolvable devices.

The stent, much like the iPhone, is a great example of the ground truth of any technology with a big impact—it takes many steps, mostly in anonymity, several coincidences, quite a few guesses, and the convergence of multiple little breakthroughs to arrive at the big “aha” moment. Stents have evolved from basic mechanical scaffolds to sophisticated drug-delivery systems. This evolution continues with the integration of “smart” technologies and the emergence of bioresorbable platforms.

Let’s start with a simple question — what is a stent?

A stent is a small, tube-like device inserted into the body to keep a passageway open, usually within blood vessels. While stents have many uses, the colloquial use of the term describes a technology that helps treat blockages caused by atherosclerosis (plaque buildup), thus improving blood flow to the heart.

The term “stent” originated with Charles Thomas Stent, a 19th-century English dentist who developed a compound for dental impressions. While he never envisioned cardiovascular applications, his name became synonymous with supportive medical devices. Johannes Fredericus Esser, a Dutch plastic surgeon, used a version of stents for reconstructive surgery on soldiers who suffered facial wounds during World War I. The devices were later used to help with bile duct issues and other parts of human anatomy. (Read: “Stent: The Man and the Word Behind the Coronary Metal Prosthesis.”)

In 1977, Andreas Gruentzig performed the first coronary balloon angioplasty at University Hospital Zurich. This breakthrough procedure, while significant, faced numerous challenges, but it is widely viewed as the start of the modern era of stents in cardiovascular medicine. Eight years later, Julio Palmaz and Richard Schatz (of Johnson & Johnson) developed the first practical balloon-expandable stent. They created a stainless steel mesh tube that could keep the blood vessels open after angioplasty. The first such device was implanted in 1987, and in 1994, the U.S. Food and Drug Administration granted approval for the stent.

Things continued for a few years, but the next big and real game-changer came in the early 2000s with the development of drug-eluting stents (DES). By coating the metal scaffolds with medications that prevent re-narrowing, companies like Johnson & Johnson (Cypher) and Boston Scientific (Taxus) created stents that dramatically improved success rates. These advances turned stents into blockbuster products.

Think of everything before the emergence of DES as the pre-smartphone era. The early experiments and efforts of stents were akin to rotary phones. Just as early phones were used for basic voice calls, early stents were simple balloon angioplasties—functional but basic, and with limitations. The emergence of bare-metal stents in the 1980s would be like the emergence of Nokia 3310 at the dawn of the mobile era. Sure, they were reliable and basic like the Nokia 3310 phone, but they were still a significant advancement. However, they had issues. Restenosis, the re-narrowing or blockage of an artery at or near the site of a previous treatment, would recur in 20% to 30% of cases. Other complications also plagued these early devices.

I would compare the introduction of the first drug-eluting stents by Johnson & Johnson to the “BlackBerrys” of the stent world. Just as BlackBerry made email on the go easy, these new stents added medication to the metal scaffold. That was a massive game-changer. Sure, they had their issues, but they made a big impact. I feel that positive impact every day. My Taxus stents keep me ticking.

Since 2007, however, new versions of DES stents have come to market. They are sleeker, more reliable, and generally offer a better experience for the patient. Just as Apple’s iPhone provided a new, sleeker, and better user experience over its predecessors — Palm, BlackBerry, and Nokia — the second generation of DES stents came with better drug delivery and fewer complications. In the 17 years since I received my stents, stents have improved by leaps and bounds. Today’s stents are ultra-thin and highly sophisticated and come with advanced features such as bioabsorbable polymers and thinner struts.

A modern coronary stent uses a cobalt-chromium or platinum-chromium alloy platform with ultra-thin struts (60-65 micrometers), representing a significant reduction from both first-generation bare-metal stents and first-generation drug-eluting stents (130-140 micrometers). Despite thinner struts, modern alloys provide superior radial strength compared to the 316L stainless steel used in early stents.

Other improvements include designs with open-cell architecture and flexible links for better vessel conformability. The surface is electropolished to enhance biocompatibility and reduce thrombogenicity. The biodegradable polymer coating (5-8 micrometers thick) carries antiproliferative drugs (100 micrograms per square centimeter) and dissolves within 6-24 months. These improvements deliver better outcomes with restenosis rates of less than 5%, compared to 20-30% in bare-metal stents (BMS) and 5-10% in first-generation drug-eluting stents (DES). And the stent makers are not done yet. Future innovations include fully bioabsorbable platforms, smart monitoring capabilities, and personalized designs.

I am going to continue with torturous use of my smartphone analogy, so bear with me. Just as the iPhone is now facing future competition from an emerging class of AI-powered devices, stents and their innovation machine are starting to feel a whiff of headwind from GLP-1 drugs like Ozempic, Wegovy, and Mounjaro.

These GLP-1 drugs are helping improve cardiovascular health by aiding weight loss, reducing plaque buildup, improving vessel flexibility, and helping control blood pressure. They can induce metabolic changes such as decreased inflammation, improved lipid profiles, and enhanced glucose control. These factors together slow the progression of atherosclerosis, improve blood vessel function, and lower the risk of blood clots. I know these are less sensational aspects of Ozempic compared to writing hot takes about weight loss, celebrities, and all things tabloid.

According to some recent data, GLP-1 drugs will lead to a reduction in stent procedures, potentially decreasing the need for invasive interventions. Boston Scientific reported a 3% to 5% decline in procedures in the third quarter of 2023, while Medtronic said it is monitoring “potential headwinds.” No one wants to talk about it loudly – which is usually a sign that these drugs will have an impact on demand. Some analysts think there could be as much as 15% reduction in stent procedures by 2026.

All that doesn’t matter to me as someone who lives with cardiac disease. They are the Batman and Robin for me – I don’t care who is whom. For me, GLP can help control certain aspects of my life, and stents have already proved to extend my life. When it is time for me to get a new stent, I now know that stent technology has come a long way and is likely to help me live better. I think millions of others who are in the same boat will be grateful for one or both.

As for me—on my 17th rebirthday, I can’t live without the stents and am ever so grateful for the innovators and tinkerers who are helping improve them day by day. Thanks to them, I can live with this reality.

Time has a strange habit of slinking away. It does so quietly that we don’t notice it till it’s too late. And what you are left with are fragments, or what we grandiosely call memories. You remember some days, a few moments, and a handful of faces, and they all add up to become your past. Today is one of those red letter days — fifteen years ago, I faced mortality, and somehow I came out on the other side. Looking back, what seemed like a dark period in my life has turned out to be the best thing that has ever happened to me. 

It taught me the lessons we learn late in life early: excess, perfection, and accumulation are fair-weather friends. I learned that by giving time to play its hand, I would stop being impatient. Life, as it turned out, has been much better than how I had planned it. And more importantly, you are better off finding comfort in the company of imperfection.

December 28, 2024. San Francisco.

Notes from (previous) Rebirthdays: #0, #1, #2, #3, #4, #5, #6, #7, #8, #9, #10, #11, #12, #13, #14, #15, #16.