Commentary
The Food and Drug Administration approved the first fully absorbable vascular scaffold designed for use in coronary arteries, the Absorb GT1 bioresorbable vascular scaffold system, made by Abbott.
Concurrent with the FDA’s announcement on July 5, the company said that it plans to start immediate commercial rollout of the Absorb bioresorbable vascular scaffold (BVS). Initial availability will be limited to the roughly 100 most active sites that participated in the ABSORB III trial, the pivotal study that established noninferiority of the BVS, compared with a state-of-the-art metallic coronary stent during 1-year follow-up, according to a company spokesman.
Dr. Hiram G. Bezerra
However, the ABSORB III results, reported in October 2015, failed to document any superiority of the BVS, compared with a metallic stent. The potential advantages of a BVS remain for now unproven, and are based on the potential long-term advantages of using devices in percutaneous coronary interventions that slowly degrade away and thereby eliminate a residual metallic structure in a patient’s coronaries and the long-term threat they could pose for thrombosis or interference with subsequent coronary procedures.
“All the potential advantages are hypothetical at this point,” said Hiram G. Bezerra, MD, an investigator in the ABSORB III trial and director of the cardiac catheterization laboratory at University Hospitals Case Medical Center in Cleveland. However, “if you have a metallic stent it lasts a lifetime, creating a metallic cage” that could interfere with a possible later coronary procedure or be the site for thrombus formation. Disappearance of the BVS also creates the possibility for eventual restoration of more normal vasomotion in the coronary wall, said Dr. Bezerra, a self-professed “enthusiast” for the BVS alternative.
A major limiting factor for BVS use today is coronary diameter because the Absorb BVS is bulkier than metallic stents. The ABSORB III trial limited use of the BVS to coronary vessels with a reference-vessel diameter by visual assessment of at least 2.5 mm, with an upper limit of 3.75 mm. Other limiting factors can be coronary calcification and tortuosity, although Dr. Bezerra said that these obstacles are usually overcome with a more time-consuming procedure if the operator is committed to placing a BVS.
Another variable will be the cost of the BVS. According to the Abbott spokesman, the device “will be priced so that it will be broadly accessible to hospitals.” Also, the Absorb BVS will receive payer reimbursement comparable to a drug-eluting stent using existing reimbursement codes, the spokesman said. Abbott will require inexperienced operators to take a training course to learn proper placement technique.
Dr. Bezerra admitted that he is probably an outlier in his plan to quickly make the BVS a mainstay of his practice. “I think adoption will be slow in the beginning” for most U.S. operators, he predicted. One of his Cleveland colleagues who spoke about the near-term prospects BVS use last October when the ABSORB III results came out predicted that immediate use might occur in about 10%-15% of patients undergoing percutaneous coronary interventions, similar to the usage level in Europe where this BVS has been available for several years.
Dr. Bezerra has been a consultant to Abbott and St. Jude. He was an investigator on the ABSORB III trial.
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