ATLANTA — Drug-eluting stents have been a source of controversy for years. Many question their safety or their efficacy, while others say that these popular devices are being implanted far too often. But one of the greatest questions surrounding the device: is it safer than a bare metal stent (BMS)?
According to two research studies that were released at the American College of Cardiology (ACC; Washington) meeting on Tuesday afternoon the answer is maybe . . . perhaps . . . but more research is needed to know for sure.
In the first study presented at the meeting Danish researchers looked at 626 patients examining the effectiveness and risks of the two types of stents implanted right after a major heart attack for a three-year-period.
The group discovered patients who received BMS systems were far more likely to have complications – such as requiring more intervention for blockages, while patients who had Drug-eluting stent (DES) systems implanted were more likely to die from heart-related problems.
A little more than 6% of patients in the study who received DES treatment died, compared with the 2% who got the BMS, according to Peter Clemmensen, MD, of Copenhagen University, a lead researcher for the study.
"It could have been a play of chance, that we had sicker patients in the DES arm," Clemmensen said during a media press conference."We have seen a signal here. But before doctors stop using these devices perhaps they could wait for longer term studies for a larger trial."
During the press conference Clemmensen said that an ideal number of patients would be 18,000 for this type of trial and would be a more useful number to determine if the "deaths" were a direct side affect of treatment with the DES.
But the chances of doing an 18,000 patient trial tracking mortality rates in DES usage would be difficult and extremely time consuming, according to David Holmes Jr. MD, a moderator for the press conference.
In the PASSION study, a separate trial, five-year findings from it suggest that safety and benefits of DES compared with BMS in acute heart attack show there is no statistically significant difference in either the safety or efficacy between the two groups.
The findings of this study contrast with researchers' belief that the paclitaxel-eluting stent would perform significantly better for cardiac death, recurrent heart attack, and target lesion revascularization. The results also failed to show a statistically significant difference between the two stent types in preventing very late stent thrombosis.
Research also pointed out a two-fold increase in the occurrence of definite stent thrombosis in the DES group compared with the BMS group – at 3.6 % and 1.7%, respectively – the occurrence of both definite and probable stent thrombosis, was comparable, at 3.9% and 3.4%,respectively.
The five-year data follow in line with both PASSION's one-year data and two-year data – which also found no statistically significant safety or benefit differences between the two stents – but the study shows that the five-year results are especially important to examine in light of data in clinical registries that associate DES use with very late stent thrombosis.
"This is a difficult choice to make,"said Maarten Vink, MD, of the Onze Lieve Vrouwe Gasthuis Hospital (Amsterdam, the Netherlands). "There is no difference between DES and BMS - but there is a chance of stent thrombosis with DES." He added that based on the results of the PASSION trial, "there was no reason to implant older generation DES in patients."
PASSION was undertaken between March 2003 and December 2004 and randomized 619 patients with acute heart attack received either treatment with a BMS or DES.
But the elephant in the room for the PASSION trial is the same as for Clemmensen's study - there were just not enough patients to take part to come to a more solid conclusion.
It's a sticking point that Vink acknowledges.
"Right now, the clinical guidelines are not conclusive concerning the use of drug-eluting stents in angioplasty for acute heart attack, as the European Society of Cardiology does not define if they should be used, while the American College of Cardiology provides an indication for them," Vink said. "Because the guidelines are not uniform, I think their use will remain an issue—one without a definite answer— until we have data from more large, randomized, long-term studies."
Another issue is the fact that the PASSION study tested older generation DES and does not account for the recent breakthroughs with the stents.
Vink was asked if he thought it would be feasible to have a study testing more current generation devices.
"The way technology is evolving you're always going to be a step behind," he told reporters during the conference.
"Already later generation devices have shown better results than the stents we've used in [PASSION]."
So what is the answer? Which is better?
At this point researchers point out that larger studies must be done.
Omar Ford, 404-262-5546;