Reassuring Registry Data Suggest Scaffold Thrombosis Rates with BVS Declining

PARIS, France—The lessons have been learned and the safety concern no longer appears to be on the table.

Those were the enthusiastic conclusions of a group of experts keying in on multiple reports presented this week at EuroPCR 2016 evaluating the safety of the first-generation everolimus-eluting bioresorbable vascular scaffold (Absorb; Abbott Vascular).

A lot of the data are early, including 30-day outcomes among patients treated in Italian and French registries and an analysis examining the effect of stopping dual antiplatelet therapy on late scaffold thrombosis, but experts are sufficiently relieved that the earlier safety signal appears to have settled. 

“There is a lesson to learn and we learned that lesson, unfortunately, through mistakes, but this is the way we learn,” Tommaso Gori, MD (University Medical Center, Mainz, Germany), told TCTMD. “I think it’s really important that we learn the limits of this generation of device. Later generations will come and the device will be improved, but the message is that if we respect the rules, and you understand what the rules are, the safety issue should really be off the table. It should be seen as a positive thing. We’ve learned what not to do and now we can do things right.”

Gori, who was part of a panel discussion highlighting selected reports on the Absorb scaffold, said his hospital recently adopted a strategy for implanting the bioresorbable vascular scaffolds. The strategy includes predilatation, implanting the device only in reference vessels of the same size, and postdilatation. Avoiding small vessels and ostial lesions is also recommended.

“Once you respect those rules—and those are simple rules—there is no safety issue with the device,” he said.

Rates Less Than 1% at 30 Days

Overall, the 30-day rate of scaffold thrombosis ranged from 0.7% in a group of 1,505 consecutive patients treated with the bioresorbable vascular scaffold in the Italian ABSORB registry to 1.05% in more than 2,000 patients treated with the device in France. In the pivotal ABSORB III trial, scaffold thrombosis was 1.5% at 1 year.

René Koning, MD, president of the French Society of Interventional Cardiology, who presented the results of French ABSORB registry, said the 30-day rate of scaffold thrombosis is “acceptable,” with the results continuing to improve as physicians pay more attention to the implantation rules. He noted that young patients are receiving the device in France, with an average age of just 55 years among patients treated with Absorb in their registry.

In a second Italian registry, one that included 1,002 patients with diffuse and multivessel disease, the rate of scaffold thrombosis was 0.6% at 30 days. In addition, one patient died from noncardiac causes and device-related cardiac events occurred in 3.3% of patients. Anna Sonia Petronio, MD (University of Pisa, Italy), who presented the results of the analysis, said that 96% of the Absorb-treated patients received postdilatation, including 87% with a noncompliant balloon. She said the rate of scaffold thrombosis is equivalent to the 30-day rate of stent thrombosis expected with drug-eluting stents.

For Petronio, given that patients had diffuse coronary artery disease, including nearly 60% of patients with acute coronary syndrome, the results suggest that the bioresorbable vascular scaffold, “if it is accurate with a good technique of implantation,” can be safely put in a group of patients in which the device is frequently contraindicated, such as those in their registry.

And finally, Robert-Jan van Geuns, MD (Erasmus Medical Center, Rotterdam, the Netherlands), presented data on 841 patients treated with Absorb as part of four different clinical trials. At 1 year, late stent thrombosis was documented in five patients (0.83%), all of whom were still taking dual antiplatelet therapy. Between 12 and 15 months, a period in which patients had stopped dual antiplatelet therapy, an additional three scaffold thrombosis events were documented. In these patients, malapposition at implant, underexpansion, and overlapping stents were the reasons for the scaffold thrombosis, all of which indicate suboptimal implantation, said van Geuns. On the whole, the effect of stopping dual antiplatelet therapy is similar after implantation of Absorb or drug-eluting stents, he added.  

Giuseppe Musumeci, MD (Ospedali Riuniti di Bergamo, Bergamo, Italy), one of the panel discussants, called the emerging data “very good,” saying the lesson is that the dissolving stent can be used if other technologies, such as “aggressive” pre- and postdilatation, are also involved.

Shirish Hiremath, MD (Ruby Hall Clinic, Pune, India), another panelist, said the ideal candidate for a bioresorbable scaffold—since it is completely broken down and dissolved within 36 months of implantation—is a young patient with long lesions and diffuse disease. These are the patients most likely to return to the cardiologist’s office for arterial renarrowing, he said.

To TCTMD, Mori said the data presented at EuroPCR weren’t anything out of line with what he’d expected to see. Earlier this year, his team published an analysis showing the rate of scaffold thrombosis to be as high as 3% at 1 year. However, after adopting a rigorous implantation protocol with Absorb, the group lowered the incidence to 1.0% at 12 months. Today, the rate of scaffold thrombosis with Absorb is approximately 0.7% in their practice.

“Now we can put the devices in with confidence,” said Mori. “We should not be afraid at the table.”

• Cortese B. 30-day outcome of the Italian ABSORB registry (RAI), a prospective registry of consecutive patients treated with biovascular scaffold. Presented at: EuroPCR 2016. May 17, 2016. Paris, France.
• Petronio AS. 30-day results of the Italian diffuse/multivessel disease ABSORB prospective registry (IT-DISAPPEARS). Presented at: EuroPCR 2016. May 17, 2016. Paris, France.
• Koning R. France ABSORB registry: In-hospital and one-month results in 2,000 patients. Presented at: EuroPCR 2016. May 17, 2016. Paris, France.
• Van Geuns RJ. Effect of DAPT termination at 12 months on very late scaffold thrombosis in regular clinical practice: data on a regional collaboration including 868 patients. Presented at: EuroPCR 2016. May 17, 2016. Paris, France.

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• FDA Panel Overwhelmingly Supports Absorb Bioresorbable Stent
• Increased Risk of Device Thrombosis With Bioresorbable Scaffold, but Some Say Risks Can Be Mitigated
• Increased Early Risk of Stent Thrombosis with the Absorb Bioresorbable Scaffold