Biomedical Engineering Reference
In-Depth Information
In 2009, Boston Scientific reported 2-year data from its SYNTAX clinical trial
comparing percutaneous coronary intervention using the Taxus
®
Express
®
Paclitaxel-
Eluting Coronary Stent System to CABG surgery. The overall results demonstrated
no statistically significant difference between the two procedures in the composite
safety endpoint (all-cause death, stroke, and myocardial infarction).
DES Versus Bare Metal Stents
A prospective, placebo-controlled, double-blind, multicenter randomized trial has
shown that in comparison with a BMS, implantation of the PES in a patient popula-
tion with complex lesions effectively reduces clinical and angiographic restenosis
(Stone et al.
2005
). According to another study, DES is a safe and effective
treatment for MI, provoking no increase in complications when compared to con-
ventional stenting and cutting the risk of arterial renarrowing by 90% (Cheneau
et al.
2005
). This fills an important information gap in the treatment of high-risk
patients. Until now, patients with MI have been excluded from studies of DES.
Physicians, however, often use drugs and devices that have been approved in one
group of patients to extend treatment to a new group of patients. There is increasing
use of DES as the primary treatment for acute MI. In this study, patients treated
with the Cypher stent (Cordis Corporation) were compared to MI patients who had
been treated with a BES in the preceding 5 years. Treatment of MI patients with the
DES was found to be safe. There was no difference between the two groups in
procedural complications. Another important finding was that no patient developed
subacute thrombosis, a serious complication, in the DES within a month of treat-
ment. This is especially reassuring, given that MIs are themselves often caused by
a thrombus that blocks the artery following rupture of an inflamed plaque. The
study also showed that DES accomplished their primary purpose, preventing the
need for a repeat procedure to treat renarrowing in the stented artery. At 6-month
follow-up, only 1% of patients treated with the DES required a new procedure to
reopen the artery, as compared to more than 10% of patients treated with the bare
metal stents. The investigators of this study are now considering a trial of head-to-
head comparison of two types of DES in the treatment of heart attack: the Cypher
stent and its competitor, the Taxus stent (Boston Scientific), which is coated with a
different anti-restenosis drug − paclitaxel.
One study compared the efficacy of the sirolimus-eluting stent (SES), the
paclitaxel-eluting stent (PES), and the BMS for long coronary lesions (Kim et al.
2006
). The study concluded that use of DESs for long coronary lesions appears to
be safe and more effective than the use of BMSs in terms of restenosis and adverse
clinical events. SES use was associated with lower late luminal loss and a lower
angiographic restenosis rate compared with PES use. A study has pooled analysis
of data from several double-blind trials in which a large number of patients were
randomly assigned to receive either PES or SES or BMS and analyzed the major
clinical end points of the trials (Stone et al.
2007
). Results showed that stent throm-
bosis after 1 year was more common with both SES and PES than with BMS. Both
DES were associated with a marked reduction in target-lesion revascularization.
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