The ABSORB III trial included 2,008 patients treated at 193 mostly U.S. centers.

Target lesion failure happened between 12 and 24 months in 3.7 percent of patients with the Absorb BVS and 2.6 percent of patients who had the Xience stent, but after that time, lesion failure-rates diverged significantly.

Absorb BVS recipients had trouble 10.9 percent of the time, those getting Xience stents, 7.8 percent.

“This difference was largely driven by target vessel heart attack, which occurred in 7.3 percent of patients receiving Absorb BVS and 4.9 percent of patients receiving Xience,” noted the report, adding that “the risks of cardiac death, ischemia-driven target vessel revascularization and development of blood clots around the stent were not significantly different between the two study arms.”

The trial's protocols restricted the diameters of vessels getting the stents to 2.5-3.75 mm.

But it let clinicians estimate diameter by eye on angiograms, which led to 19 percent of those getting stents who had smaller than the currently recommended 2.25 mm. diameter, as assessed by quantitative coronary analysis – about the same as 2.5 mm. by eye.

“These patients had significantly poorer outcomes than those whose treated vessels were at least 2.5 millimeters in diameter, and a sub-analysis excluding these patients showed Absorb BVS to be no longer significantly worse than metal stents at two years, in terms of target lesion failure,” according to the release.

"These results show that this device is generally comparable with the drug-eluting metal stent when the device is placed in appropriately-sized vessels, and placed using appropriate procedural techniques," Ellis said, who advised that "the value proposition of the Absorb BVS is that once the device is fully dissolved after three years, there will be better long-term outcomes, but there are as of yet no long-term, large studies available to show that."

Procedural changes since the ABSORB III trial that improve outcomes may also make a difference, suggested the company, and these are part of a separate ABSORB IV trial now getting underway.

When the Absorb was approved by the FDA in July, 2016, it was called “a major advance in the treatment of coronary artery disease," by Dr. Gregg W. Stone of the Center for Interventional Vascular Therapy at Columbia University Medical Center, New York-Presbyterian Hospital and the chairman of the ABSORB clinical trial program, as HCB News reported at the time.

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