May 17, 2012

May 16, 2012 (Paris, France) — Use of a bioerodable polymer, biolimus-eluting stent (BES) in patients with ST-elevation MI (STEMI) can radically reduce the rate of major adverse cardiac events (MACE) at one year, the COMFORTABLE-AMI study suggests.

Dr Lorenz Räber (Berne University Hospital, Switzerland), who presented the results here at EuroPCR 2012, estimated that only 24 patients would need to be treated with BES to avoid one major event. The major driver of this benefit was a reduction in both target vessel reinfarction and target lesion revascularization, Räber noted.

"None of the previous trials enrolling STEMI patients have shown a safety advantage with respect to myocardial infarction," Räber commented. "HORIZONS AMI showed a benefit in terms of efficacy, but not in safety."

In COMFORTABLE AMI, investigators randomized 1161 STEMI patients 1:1 to a biolimus-eluting stent or a bare-metal stent, following patients for MACE.

At one year, the MACE rate was 8.7% in the bare-metal-stent arm, compared with just 4.3% in the BES arm (p=0.004). Target vessel reinfarction (2.7% vs 0.5%, p=0.01) and target lesion revascularization (5.7% vs 1.6%, p<0.001) were also significantly lower in the BES group. Stent-thrombosis rates were twice as high in the bare-metal-stent group, but the difference was not statistically significant (2.1% vs 0.9%, p=0.10).

In an analysis that looked only at target-vessel MI due to restenosis or stent thrombosis, only three BES patients had an event over one year of follow-up, as compared with 14 in the bare-metal-stent group, a statistically significant difference (p=0.01).

Of note, patients in both arms of the study took dual antiplatelet therapy for one year.

Tipping the Balance?

Bare-metal stents are considered by many to be the gold standard in STEMI care, in part over concerns that delayed vessel healing in AMI patients may potentiate very late stent thrombosis. Among the 11 participating sites in COMFORTABLE-AMI, said Räber, use of bare-metal stents range from 20% to 90% in STEMI cases.

Dr Upendra Kaul (Fortis Escorts Heart Institute, New Delhi, India), discussing the study results after Räber's presentation, said that the "superior safety concept" of bare-metal stents in AMI "is seriously questioned by new-generation [drug-eluting stents] DES" and the strategy of choosing bare-metal devices, believing them to be safer, "cannot be justified."

Longer follow-up and studies testing the possibility of shorter dual antiplatelet therapy will help interventionalists understand better just how best to manage STEMI patients, Kaul added.

Also commenting on the study for heartwire , Dr Miles Behan (Edinburgh Heart Centre, Scotland) acknowledged that bare-metal stenting has been the "default strategy" in AMI care.

"The reason we do that is, you meet the patient the first time as they get on the table, you don't know a lot about their history--the worry is, if you put in DES, you find out when they come off the table that they are scheduled for some near-future surgery. So a lot of interventionalists balance the risk of restenosis vs possible bleeding complications. There's also a concern about endothelial healing with DES and possible stent thrombosis."

While this new data help tilt the balance in favor of DES, Behan said he would still likely opt for a bare-metal stent if he could not ensure compliance with dual antiplatelet therapy, "unless there was a very strong indication for DES.

"That might be a diabetic with a long vessel lesion or a small vessel," he said.

Räber had no conflicts of interest.

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