The FDA is informing health care providers treating patients with the Absorb GT1 bioresorbable vascular scaffold (BVS) (Abbott Vascular) that an increased rate of major adverse cardiac events has been observed in patients receiving the BVS compared with patients treated with the metallic Xience drug-eluting stent (Abbott Vascular).
The Absorb GT1 BVS is used to open coronary arteries blocked by scar tissue (plaque) in order to increase blood flow to the heart muscle. The BVS is implanted during an angioplasty procedure. It gradually dissolves and is fully absorbed by the body over time.
The FDA’s initial review of two-year data from the pivotal ABSORB III trial found an 11.0% rate of major adverse cardiac events (e.g., cardiac death, heart attack, or the need for an additional procedure to reopen the treated heart vessel) in patients treated with the BVS at two years compared with 7.9% in patients treated with the metallic Xience drug-eluting stent (P = 0.03). This study also showed a 1.9% rate of thrombosis within the BVS compared with a 0.8% rate within the Xience stent at two years. These observed higher adverse cardiac event rates in BVS patients were more likely when the device was placed in small heart vessels.
In its report on the trial results, Abbott stated: “The ABSORB III study began in 2012, and since then, training on the device has evolved based on learnings in the medical community and physician experience. When Absorb was approved by the U.S. Food and Drug Administration in July 2016, the instructions for use specified the avoidance of very small vessels and included optimal implantation guidelines.”
The FDA is working with Abbott Vascular to conduct additional analyses to better understand the cause(s) of the higher cardiac event and device thrombosis rates in patients treated with the BVS compared with the Xience stent. Meanwhile, the agency recommends that health care providers: