REVIEW
SA JOURNAL OF DIABETES & VASCULAR DISEASE
68
VOLUME 7 NUMBER 2 • JUNE 2010
versus no intervention. An angiogram is essential, and tools like the
Syntax score and Euroscore can then be used to review the angiogram
to assess whether risk is high or low – and whether disease is mild or
severe. It’s imperative to intervene where disease is severe.’
Medical therapy is good up to a point, but there is still a fairly high
degree of morbidity and mortality and numbers needed to treat are
high, irrespective of the type of drug used (ARBs, ACEs, aspirin, stat-
ins). ‘Revascularisation, however, relieves ischaemia, improves quality
of life, reduces the medication burden as well as the associated adverse
events, and improves prognosis.’
He cited a number of studies in support of his view. Both the ACIP
and SWISS II studies showed that revascularisation was better than
medical therapy for the relief of ischaemia. The perfusion sub-study of
the COURAGE trial showed that it reduced ischaemia by 33% (vs 19%
for medical therapy) and severe ischaemia by 78% (vs 52%). Large
observational trials have also shown prognostic benefits associated
with revascularisation in severe ischaemia.
Dr Horak added the caveat that real-life individual patients do not
reflect the ‘perfect patients’ seen in trials. He referred to 30 trials com-
prising 44 to 2 368 patients, underscoring that all were highly selec-
tive, allowed crossover and were underpowered to detect mortality and
infarction differences.
‘The COURAGE study started the whole debate in that there was
no difference in mortality and infarct rate between the medical and the
PCI groups. Yet half the participants had minimal or no angina and the
extent of the ischaemia was not severe. Also, the quality of the revas-
cularisation was open to question, the study was underpowered, and
an over-sensitive definition of infarction was used.’
Meta-analyses have all tended to show the superiority of PCI over
medical treatment, however, with approximately 20% reductions in
mortality and myocardial infarction. Dr Horak is adamant that there
are trials that
are
sufficiently powered to prove that revascularisation
saves lives.
‘Also, we’re improving our techniques all the time. Fractional flow
reserve (FFR) guided PCI improves outcomes, while intravascular ultra-
sound (IVUS) can detect angiographically silent ischaemia. As we keep
on individualising and finding vulnerable patients, we’ll see even better
results. FFR is a functional measurement that acts as a guide to impor-
tant lesions, ensuring fewer stents per patient. With FFR guidance, we’ll
see better-than-ever results with both angioplasty and stenting in these
important lesions.’
Dr Tony Dalby, a cardiologist from Milpark Hospital, Johannesburg,
feels, however, that intervention is not to be taken lightly, especially
when it comes to diabetics. Angiograms are often difficult to inter-
pret and he contends that FFR has in some ways exacerbated this, as
often, what looks right is not, and vice versa. If the decision is made
to proceed, much thought must be given to whether the choice is for
PCI or CABG. In the COURAGE trial, adopting PCI as an initial strat-
egy provided no incremental benefit over intensive medical therapy,
including those patients with diabetes or coronary artery disease. The
BARI-2D trial showed no difference between CABG and optimal medi-
cal therapy, while also showing CABG to be superior to PCI.
Many issues need to be taken into account when dealing with dia-
betics, including age, obesity, left ventricular and renal dysfunction, as
well as the presence of rapidly progressing disease. ‘Repeat revascu-
larisation is often required in diabetics and in this regard both PCI and
CABG have a bad outlook. It is therefore important to first consider
optimal medical therapy comprising lifestyle management, glycaemic
control and aggressive secondary-prevention measures. This has to be
the basis of anything we do.’ (He acknowledged, however, that CABG
was found to be superior to optimal medical therapy in the ACIP trial.)
Patients are not always properly informed and have unrealistic
expectations of PCI. ‘Seventy per cent of patients believe it will prolong
life and 70% that it will prevent myocardial infarction’, said Dr Dalby.
‘In reality, PCI alleviates angina for two to three years – after which
further revascularisation is likely to be needed.’
If intervention is chosen, Dr Dalby feels that CABG is the better
choice. ‘The SYNTAX study, in which 30% of patients were diabetic,
set out to prove the non-inferiority of PCI to CABG. Based on the one-
and two-year results, PCI failed the test. The CARDia study produced
similar results showing that, on balance, PCI is not non-inferior. A study
by Hlatky published last year in the
Lancet
showed worse outcomes
associated with PCI in diabetics, and recommended that diabetics over
65 years should be offered CABG in preference.’
He agreed with Dr Horak that it was important to assess patients
individually. ‘Coronary anatomy needs to be correlated with symp-
toms and function, and careful thought needs to be given to when
optimal medical therapy is the best choice and intervention should be
held in reserve. Certainly we should start with optimal medical therapy
and observe, before rushing into interventional surgery. Where we do
decide to intervene, CABG should be preferred over PCI when multi-
vessel disease is present.’
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