How do the procedures compare?
Several studies have analyzed the differences between angioplasty
and CABG. One such study was the bypass angioplasty revascularisation
investigation (BARI) trial. This trial compared the impact
of PTCA and CABG on long-term mortality rates in patients
with multivessel disease suitable for both procedures. Patients
with diabetes and those without were included in the investigation.
[Brooks et al, 2000]
Diabetic patients receiving insulin had a higher risk of
death with PTCA compared with CABG, than patients without
diabetes who had similar risks with both procedures. Insulin-treated
diabetes was the only variable found to have a significantly
different impact regarding all-cause mortality in the two
treatment groups. [Brooks
et al, 2000]
It is thought that some of the difference in mortality between
PTCA and CABG could be due to restenosis after angioplasty.
Van Belle et al demonstrated that the restenosis rate after
balloon angioplasty is almost doubled in patients with diabetes.
In addition this group suffered greater late loss of lumen
diameter and a higher rate of late vessel occlusion. However,
after stenting restenosis rates were similar in people with
diabetes and those without, and late loss and late vessel
occlusion did not significantly differ between the groups.
This suggested that people with diabetes have the same improved
outcome with coronary artery stenting that has been documented
in non-diabetic patients. [Van
Belle et al, 1997]
Joseph et al showed that coronary artery stenting in people
with diabetes could be performed with acceptable immediate
and mid-term results. [Joseph
et al, 1999] Evidence has also been provided by the Benestent-I
trial for the long-term stability of stenting. [Kiemeneji
et al, 2001]
Primary stenting appears to be superior in terms of restenosis
rate to primary PTCA. However, stent thrombosis is significantly
higher in patients with diabetes. This is considered to be
associated with increased expression of glycoprotein IIb/IIIa
platelet receptor. In patients with diabetes, platelets circulate
in an activated state and have enhanced spontaneous and induced
adhesiveness and aggregability in response to several agonists.
This increased stent thrombosis causes increased in-hospital
congestive heart failure and major cardiovascular events in
people with diabetes at 1 month and at late follow-up. [Silva
et al, 1999] Stenting of coronary arteries in patients
with diabetes is associated with significantly increased lumen
renarrowing compared with patients without diabetes, regardless
of treatment modality for diabetes. [Schofer
et al, 2000]
Because of the high rate of restenosis associated with stenting
in people with diabetes, more recent trials have studied patients
who have been administered the platelet glycoprotein IIb/IIIa
inhibitor, abciximab, adjunctively. [Lincoff,
2000] The combination of stenting and abciximab during
percutaneous interventions confers additive long-term benefit
with respect to death, myocardial infarction and target revascularisation.
Stenting with abciximab:
 |
 |
decreased 6-month rate of death or myocardial infarction
(MI). |
|
|
decreased repeat percutaneous or surgical revascularisation. |
|
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increased survival at 1-year and follow-up. |
|
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increased the safety profile of stenting. |
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How do the costs of these procedures compare?
Primary stenting for acute myocardial infarction
results in a better long-term clinical outcome compared with
PTCA without increased cost. [Suryapranata
et al, 2001] Coronary artery stenting for multivessel
disease is less expensive than CABG but is associated with
a greater need for repeated revascularisation [Serruys
et al, 2001].
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Who should receive which therapy?
PTCA is often used for patients with diabetes presenting
with severe CHD and in need of urgent treatment. This is because
the procedure rapidly restores perfusion of the myocardium.
Further revascularisation procedures may be needed after emergency
revascularisation.
In general, the best candidates for stenting have single
vessel disease in a major artery. However, it can be used
in various situations:
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patients with early single vessel disease. |
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patients with early multivessel disease. |
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patients who have already received angioplasty in an
emergency situation. |
Because people with diabetes tend to present with increased
rates of restenosis and more extensive disease, the likelihood
of complete revascularisation with percutaneous techniques
is reduced. Therefore, CABG remains the preferred treatment
in those people with diabetes with multivessel disease.
The decision regarding the choice of revascularisation procedure
should take into account angiographic characteristics, clinical
status and patient preference.
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