Abbot Vascular is touting a first-of-its-kind, fully dissolving artery stent, but some physicians wonder whether it's an improvement over existing treatments.
The biodegradable stent approved Tuesday is absorbed by the body over roughly three years. Several physicians and experts interviewed don't see a significant benefit to the device, especially when research suggests that stents may be overused in treating patients with coronary artery disease anyway. One expert believes the innovation is just meant to spark interest in a stale market.
In a trial that found the device to be as safe and effective as its predecessor, the new device, Absorb, had a higher rate of complications than Abbott's metallic Xience stent, by 1.7 percentage points. But that isn't a statistically significant difference. Physicians noted that it likely isn't clinically significant either.
Dr. Roxana Mehran, an interventional cardiologist at Mount Sinai Health System in New York, said on Tuesday that the new device presents an option for patients who don't want to have a foreign body in their arteries forever. Mount Sinai participated in trials for the stent.
“Most patients would not like to have a foreign body in their arteries,” Mehran said, while noting that existing metallic stents are very effective. She said it'll be up to physicians to choose what's best for their patients.
From a clinical perspective, Abbott says the device will allow the artery to pulse and flex naturally, reduce the risk of future blockages that occur with metallic stents, and make it easier for patients to undergo future procedures.
The fact that a dissolving stent can keep the artery healthy but clear for future bypass or surgery is a significant benefit, Mehran said. But several clinicians said this advantage is limited to rare cases for patients with multiple stents, and most of those procedures take place in a lower section of the artery.
Several experts wondered why a patient would want or need an absorbable stent. They don't believe absorption offers any significant clinical benefit, and think the stent is the result of patient demand that isn't based on science.
“I think it's a marketing scam to increase sales in a stale stent market,” said Dr. David Brown, a general cardiologist at Barnes-Jewish Hospital in St. Louis and a professor at the Washington University School of Medicine. He's a former interventional cardiologist.
An Abbott spokesman said the device will be priced at a “modest premium” to its current stent offering. The company wouldn't disclose specific pricing or sales forecasts for competitive reasoning, but said the device will be coded similarly to existing drug-eluting stents.
Studies show risks to having leads and metals in artery walls, Brown acknowledged, but his own research shows that some patients may not need a stent at all.
In 2012, Brown co-authored a study published in the Archives of Internal Medicine that analyzed clinical trials of stents. He and his colleague found no evidence that using stent implantation as an initial treatment in stable coronary artery disease patients offered any improvement over medical therapy in preventing death, nonfatal heart attacks, chest pain known as angina, or unplanned revascularization procedures, like bypass and angioplasty. Even if a patient receives a stent, they still require medical therapy.
In the Abbott trial, about 70% of patients who received the new, dissolving Absorb stent presented with stable coronary artery disease, the population for which Brown's study found that trying medical therapy first might be equally as beneficial and obviously less risky.
The procedure, known as percutaneous coronary intervention, is expensive, costing Medicare an average of over $15,000 per procedure. Private payers pay an even higher rate, and this is in addition to necessary medical therapy. Across payers, it's estimated that $7.5 billion is spent each year on these procedures.
An analysis published Tuesday by researchers at Newark, Del.-based Christiana Care Health System argues that, from a value perspective, "until such definitive scientific evidence becomes widely available, patients, clinicians, payers and health policy makers would be best served by adhering to the present body of evidence” and looking to medical therapy first.
But Brown said the question of whether a stent should be used isn't something most interventional cardiologists are thinking about.
“That conversation is not being had in the cath lab,” Brown said. “Once you're there, you're on the assembly line and you're going to get re-vascularized more times than not. The real question is not are these stents going to be put in inappropriately, but what percentage of the inappropriate stent market is going to be shifted to bioabsorbable, and that'll strictly depend on promotion.”
In the case of this new stent and further stent innovation, physicians and hospital supply chain executives need to look at each new innovation critically instead of rushing toward patient demand, said Dr. Neil Thomas, an attending cardiac surgeon at Northwestern Medicine Central Dupage Hospital in Winfield, Ill. Although stents may have been shown to be overused or inappropriately used by some physicians, they still have a role in cardiovascular care.
"What these large trials have taught us is that while the technology may be overused in stable patients, they are not useless,” Thomas said. “On the contrary, what it means is that we have to target the groups for whom we use stents more carefully.”
