(Adds FDA comment)
By Bill Berkrot
WASHINGTON, March 18 Patients who received
Abbott Laboratories' novel dissolving vascular stent had
a significantly higher rate of serious adverse heart events than
those treated with the company's widely used Xience drug-coated
metal stent two years after implantation, according to data
presented on Saturday.
New guidelines for blood vessel size and proper implantation
techniques put in place for the new Absorb stent since the study
began, however, should lead to better results, researchers said.
They reported that 19 percent of those who received Absorb
in the 2,008-patient trial had it implanted in blood vessels now
deemed too small for the device, hurting overall results.
"The difference between Absorb and Xience when they're both
implanted in properly-sized vessels with good procedural
technique is likely to be quite modest and possibly not
clinically important," said Dr. Stephen Ellis, director of
interventional cardiology at Cleveland Clinic, who presented the
data at the American College of Cardiology scientific meeting in
Stents are tiny tubes used to prop open diseased arteries
cleared of blockages. The two stents demonstrated similar safety
between one and two years, but a difference turned up by the end
of year two.
Absorb, which is larger than traditional metal stents, is
made of a plastic designed to fully dissolve over the course of
about three years, leaving a naturally flexible blood vessel.
After two years, 10.9 percent of Absorb patients had
experienced target lesion failure, versus 7.9 percent for
Xience, a statistically significant difference.
TLF combines heart-related death, heart attack related to
the treated vessel and need for repeat procedure due to
reclogging of the treated part of the artery. The TLF finding
was driven by a higher rate of heart attacks - 7.3 percent for
Absorb versus 4.9 percent for Xience.
The difference between the two stents declined and was no
longer statistically significant when the smaller-vessel
patients were excluded, researchers reported.
The U.S. Food and Drug Administration said it was informing
healthcare providers of the increased rate of major adverse
cardiac events observed in patients receiving Absorb in the
study. The agency said it will continue to monitor Absorb's
performance in clinical studies and reports submitted to it.
Absorb won U.S. approval last July, but longer-term data is
needed to assess its true value.
All of the benefit of using the larger, more-difficult-to-
place stent, "if there is going to be a benefit, will come after
it has been fully absorbed," said Ellis.
"We await long-term outcomes," he added. "If this device
doesn't produce better long-term outcomes, there's no point in
(Reporting by Bill Berkrot; Editing by Dan Grebler)