The BVS Disappearing Stent: Promise, Hype and the Tension Between Progress and Safety

Medicine does not stand still. You want innovation; you want progress. But you also want safety.

Millions of patients have coronary stents placed in the arteries supplying blood to the heart. It’s big business.

Metal cages placed in the setting of a heart attack can be life saving. In other settings, however, the strongest quality evidence says metal cages perform no better than medicines.

One of the two* main reasons stents don’t improve long-term outcomes for patients with stable coronary disease are that they trade improved blood flow (good) for the presence of a metal cage in the artery (bad). The metal cage can stimulate inflammation and cause the artery to lay down more blockage (neo-atherosclerosis). Also, the exposed metal can attract platelets and form clots (really bad).

But what if you could design a stent that dissolved over time? It opens the blockage, improves blood flow, stabilizes the vessel, and then disappears.

This is the promise of Abbott Vascular’s Absorb GT1 bioresorbable vascular scaffold (BVS) system. It’s been used in Europe since 2011 and was just approved by the FDA.

In my most recent column over at theheart.org | Medscape Cardiology, I discuss the tension between progress and safety in regards to the disappearing stent. Central to this issue is understanding hype.

You will soon see direct-to-consumer ads from Abbott Vascular.

Be careful.

In my column, which is written for physicians, I make the case that BVS has great potential–but the actual evidence is dubious. In medical speak, we say the disappearing stent is “non-inferior.” A more neutral look at the evidence suggests it’s closer to inferior.

For instance, the risk of stent failure–sometimes manifested by catastrophic events, such as clotting off abruptly–is 2-3 times greater with the disappearing stent.

The BVS system takes three years to dissolve, so that’s when we’d expect benefits. The problem is we don’t have data that goes that far out; not even close. Yet the FDA advisors easily approved it–some even making glowing remarks.

Another oddity is that the arguably inferior stent will cost more. How is that right?

Finally, make no mistake, this is more than just a debate about a new stent.

The bigger picture is seeing through the fog created when therapeutic optimism, marketing hype and the drive for medical progress mix together.

The title of my column on theheart.org on Medscape is Dissolving Coronary Stents: The Fog of Hype. Here is the intro:

The recent approval by the US Food and Drug Administration (FDA) of the Absorb GT1 bioresorbable vascular scaffold (BVS) system (Abbott Vascular) got me thinking about a modern-day medical problem: the tension between progress and safety.

Precarious is the balance between embracing the new and sticking with the tried and tested—pioneer vs Luddite. Interventional cardiologists are known for their pioneering spirit. By definition, a pioneer takes risks and sometimes suffers consequences.

We allow novel devices leeway because future iterations of a new device often prove beneficial. In general, current-generation drug-eluting stents (DES) perform better than the original versions.[1]

But newer is not always better. The heart rhythm community, including me, in my gullible days, accepted low-profile implantable cardioverter-defibrillator (ICD) leads, such as Medtronic’s Sprint Fidelis. This embrace had disastrous consequences for patients.

Read more…

JMM

* The second reason stents don’t improve long-term outcomes in stable coronary disease is that they are a focal (one spot) answer for a systemic (all-over) disease of atherosclerosis. What’s more, the tightest blockage does not usually cause the heart attack.

Atherosclerosis, or hardening of the arteries, is a disease best treated with all-over things, such as low-inflammation diets, exercise, sleep and fulfilling lives. Oh, and not smoking.

I discuss these concepts in a post about George Bush’s stent procedure. See also… An electrician’s view of smooshing blockages…