Abbott Vascular's Absorb Bioresorbable Vascular Scaffold Studied for BTK Treatment

August 30, 2016—In 12-month clinical and imaging follow-up, the Absorb everolimus-eluting bioresorbable vascular scaffold (Abbott Vascular) demonstrated excellent safety, patency, and freedom from target lesion revascularization for the treatment of below-the-knee (BTK) arteries, concluded Ramon L. Varcoe, MBBS, et al in Journal of the American College of Cardiology (JACC): Cardiovascular Interventions (2016;9:1721–1728). 

In July 2016, the fully dissolving Absorb bioresorbable coronary scaffold was approved by the US Food and Drug Administration for the treatment of coronary artery disease.

In the study, investigators performed tibial and distal popliteal angioplasty with scaffold placement using the Absorb scaffold. Clinical and ultrasound follow-up was performed at 1, 3, 6, 12, and 24 months to detect binary restenosis and evaluate safety, restenosis, and clinical improvement.

As summarized in JACC: Cardiovascular Interventions, 38 limbs in 33 patients were treated for critical limb ischemia (68.4%) or severe claudication (31.6%). Fifty scaffolds were used to treat a total of 43 lesions, with a mean length of 19.2 ± 11.6 mm. During a mean follow-up period of 12.0 ± 3.9 months, five patients died and all others were available for follow-up. 

Among the 38 treated limbs, clinical improvement was present in 30 (79%). Binary restenosis was detected in three of 50 scaffolds (6%). Using the Kaplan-Meier method, rates of primary patency were 96% and 84.6% at 12 and 24 months, respectively; and rates of freedom from clinically driven target lesion revascularization were 96% and 96% at 12 and 24 months, respectively. Complete wound healing was noted in 64% of those treated for tissue loss, with no major amputation and a limb-salvage rate of 100%, reported the investigators in JACC: Cardiovascular Interventions.

“Lower limb amputation takes a huge toll on society and is often underappreciated by our community. We have been striving to eliminate amputation from our practice by exploring novel technologies that can be used to revascularize the ischemic limb," said Dr. Varcoe when discussing the study with Endovascular Today. "Our experience using the Absorb bioresorbable scaffold to treat blocked leg arteries has demonstrated results at least as good as the best drug-eluting metal stents with several inherent advantages. The scaffold disappears over time, eliminating the irritant effect of the permanent metallic implant, but even better, it seems to facilitate a restoration of normal function, with return of blood vessel contractility. Most interventionists are trying to avoid implanting permanent metallic implants, but we still frequently need scaffolding to overcome elastic recoil and treat dissection. This device may offer the best of both worlds.”

In an accompanying editorial in JACC: Cardiovascular Interventions, Antonio Micari, MD, and Roberto Nerla, MD, discuss these finding in the context of the need to find, “effective and durable solution to prevent early restenosis and recurrent hospitalizations,” in the increasing number of patients treated with BTK interventions (2016;9:1729–1730). 

The editorial (“Vascular Scaffold for Below-the-Knee Vascular Disease: Have We Got a New Challenger?”) reviews the current contenders for a preferred interventional approach (including drug-coated balloons and drug-eluting stents) and discusses the potential for the Absorb everolimus-eluting bioresorbable vascular scaffold in this indication.

Dr. Micari and Dr. Nerla stated that the Absorb device, which is currently indicated for coronary treatment, may overcome limitations of other technology. They stated, “We congratulate the authors for reporting the long-term clinical outcome of their experience with coronary scaffolds in BTK interventions; their restenosis rate, together with the appropriate duration of clinical follow-up, actually represent a proof of concept of the great potential of vascular scaffolds in peripheral interventions.”

They continued, “Their results are in line with other recently reported experiences comparing bioresorbable vascular scaffold and drug-eluting stent results in BTK interventions in a retrospective series and showing a substantial equivalence between the two approaches. Such a finding should certainly be considered as the starting gate toward a wider and more specific assessment of these technologies in a BTK setting.”

However, they noted several limitations of the study, including a patient population with very focal lesions, whereas real-world infrapopliteal disease is known to be more diffuse and complex.

“In conclusion, the reported results are not enough to justify an enthusiastic conversion to bioresorbable scaffolds for treatment of CLI, especially because of the number of limitations and the carefully selected population, but they should be considered as pilot and idea-generating data to assess the role of BVS in this setting,” stated Dr. Micari and Dr. Nerla in JACC: Cardiovascular Interventions.