Peripheral application of bioabsorbable structures shows promise

Issue: March 2016

HOLLYWOOD, Fla. — Bioabsorbable stents and bioresorbable scaffolds may ultimately prove more suitable than metallic stents for the treatment of peripheral artery lesions, but more research is needed, an expert said at the International Symposium on Endovascular Therapy.

Michael D. Dake, MD, the Thelma and Henry Doegler professor in the department of cardiothoracic surgery at Stanford University School of Medicine and Falk Cardiovascular Research Center, said bioabsorbable stents have many theoretical advantages that could be applied to peripheral arteries. These advantages include: no permanent device is left behind; elastic recoil is less likely; flow-limiting dissection could be better treated; procedure time and contrast usage could be reduced; and late lumen loss could be reduced, he said.

Michael D. Dake

“This may allow for treatment of areas not suitable for a permanent stent,” Dake said.

However, he also discussed potential disadvantages, such as the inflammatory properties of polymers, the potential for material to become embolized and uncertainty about how much time is optimal for the stent to remain in the body.

Few studies of bioabsorbable stents in peripheral arteries have been performed, Dake said. One notable study was ESPRIT I, in which a bioresorbable vascular scaffold (Esprit, Abbott Vascular) was implanted in patients with superficial femoral artery or extreme iliac disease. At 1 year, no patients died or required amputation and 8.8% required any revascularization, Dake said. He also noted that mean Rutherford class improved and 12.9% of patients had binary restenosis. Poor results were most likely when the stent diameter was not matched appropriately to the size of the vessel, he added.

One bioresorbable vascular scaffold (Stanza, 480 Biomedical) has been specifically designed for use in the peripheral arteries, Dake said. Its braided design may help it resist the force that comes as a result of leg movement, he noted.

However, its development has had some “speed bumps” and it is “not ready for prime time,” he said.

One BVS (Absorb, Abbott Vascular) has also been tried in below-the-knee arteries, which are similarly sized to the coronary arteries, he said.

In a study of 22 patients with below-the-knee atherosclerotic disease implanted with the Absorb BVS, at 1 year there was 100% procedural success, 88% clinical improvement, 94.4% primary patency, 100% limb salvage, 5.6% target limb revascularization, 5.6% target vessel revascularization and one death, Dake said.

“Currently, there are works in progress, but all remain unrealized in their potential benefits,” Dake concluded. – by Erik Swain

Reference:

Dake MD. Session IV: Total Occlusions from Head to Toe. Presented at: International Symposium on Endovascular Therapy; Feb. 6-10, 2016; Hollywood, Fla.

Disclosure: Dake reports financial ties with Cardinal Health, Cook Medical, C.R. Bard, Intact Vascular, PQ Bypass and W.L. Gore.