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Diabetes has always
adversely affected the
outcome of percutaneous
coronary intervention
(PCI) first angioplasty
and then later stenting.
Patients with diabetes
mellitus are known to
have a higher adverse
event rate after PCI and
stenting compared with
those without diabetes.
This is mainly due to
increased restenosis and
subsequent need for
repeat
revascularization.
Patients with diabetes
have often smaller
diameter vessels and
diffuse disease. This
deadly triad (diabetes,
small vessel size and
diffuse disease) leads
to higher restenosis and
perhaps worse outcomes
compared with CABG
surgery.
Drug eluting stents have
reduced the restenosis
and the need for repeat
revascularization.
However diabetes remains
a risk-factor for
restenosis with drug
eluting stents. The
number of patients with
diabetes in randomized
trials of drug eluting
stents are relatively
low. Since these
trials were primarily
conducted for regulatory
approval, single de-novo
focal lesions were
treated. Thus the
complex disease in
diabetics was not
studied extensively.
Finally, the impact of
diabetes treatment mode
(insulin requiring
versus non-insulin
requiring) on clinical
outcomes following drug
eluting stents remains
unknown. In a real world
registry of drug eluting
stents in diabetic
patients there was only
a 23% reduction in major
adverse cardiac events
compared with bare metal
stents, less than that
is reported in
randomized pivotal
trials. Presence of small
vessel disease in
diabetics may perhaps
cause an additive effect
on restenosis following
drug eluting stents.
In a comprehensive
meta-analysis of all
studies with DES in
diabetics, Mahmud et al.
found single digit
revascularization rates
and average major
adverse cardiac event
(MACE) rates of 12% with
the Paclitaxel eluting
stents. The sub-set of
diabetic patients with
small vessels studied in
trials remains very low.
In the small vessel
sub-set of the SIRTAX
study there were only 35
patients with diabetes
with small vessels
treated with Paclitaxel
eluting Taxus stent. At
the TCT 2009 the results
of SPIRIT IV study
comparing Everolimus
eluting stent (Xience/Promus)
were compared with the
older first generation
Paclitaxel eluting Taxus
Express stent. In the
diabetic sub-group there
were 1140 patients, and
there was no difference
in the primary end point
(target lesion failure)
between the Paclitaxel
or the Everolimus
eluting stents 6.9% vs.
6.4%, P= 0.80. Thus in
diabetic patients there
was equivalent efficacy
for both stents.
Saudi Arabia has a
unique population with a
very high incidence of
diabetes. Twenty-four
percent of the adult
population is diabetic
and a further sixteen
percent have an impaired
glucose tolerance
test. The Taxus Olympia
Phase I study, in which
a significant number of
patients were recruited
from this region, had a
high 50% of incidence of
diabetes. Therefore this
offers a fertile ground
for study of drug
eluting stents in this
high risk patient and
vessel subset.
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