Paclitaxel Stent Had Wider Lumen in Acute MI Patients
Although the trial was not powered for clinical events, there was a trend toward less TVR.
Results of the HAAMU-STENT trial indicate that use of paclitaxel-eluting stents in patients with acute myocardial infarction (MI) results in wider lumenal diameter and less late loss at follow-up compared with bare-metal stents.
“The strategy of using paclitaxel-eluting stents (Taxus, Boston Scientific) in STEMI-PCI appears safe and feasible in the short term, but more data are needed on its long-term effects,” said Ilkka Tierala, MD, Helsinki University Hospital in Finland.
At angiographic follow-up, Tierala and colleagues further noted a wider in-stent minimal lumen diameter at 2.5 mm in the paclitaxel-eluting stent group compared with 2 mm in the bare-metal stent group (P < .001).
In-stent percent diameter stenosis was also lower in the Taxus group at 24% compared with 34% in the bare-metal stent group (P < .001).
Finally, late loss was lower in the Taxus group at 0.26 mm compared with 0.73 mm in the bare-metal stent group (P < .001).
Other angiographic outcomes were not significantly different between the two groups (Figure 1).
Clinical outcomes
“Our study was quite small, and it had no power to look at clinical events,” Tierala said.
Researchers, however, noticed a trend toward less target vessel revascularization in patients treated with paclitaxel-eluting stents, while other clinical endpoints were equivalent (Figure 2). In addition, stent thrombosis rates were equivalent between paclitaxel-eluting and bare-metal stents in the presence of dual antiplatelet therapy.
In a comment period following the presentation, David Faxon, MD, lecturer on medicine at the Brigham and Women’s Hospital, Boston, suggested that the differences in baseline characteristics between the patients receiving paclitaxel-eluting stents and the patients receiving bare-metal stents put the drug-eluting stent group at a disadvantage.
Although baseline characteristics were well balanced overall, patients in the Taxus group were more likely to have diabetes at baseline (21% vs. 8.5%, P = .027) and to have had previous percutaneous cornory intervention (PCI) (12% vs. 3.7%, P = .043).
A smaller trial
The mean age of the 164 patients in HAAMU-STENT was 62 years, and about 60% were men.
To be included in the study, patients had to have an ST-elevation MI with pain onset less than 12 hours prior to enrollment.
HAAMU-STENT was a single-center, investigator-initiated study. Both Tierala and Faxon agreed that a much larger cohort is needed to draw definitive conclusions.
Faxon said the HORIZONS AMI trial will enroll 3,400 patients undergoing primary PCI. Patients will be randomized in a 3:1 ratio to a Taxus stent or to a bare-metal stent.
Faxon said the hypothesis is that the use of the polymer-based, slow-release, paclitaxel-eluting stent will safely reduce the one-year rate of ischemia- driven target lesion revascularization.
“We anxiously await the results of this trial,” Faxon said.