CARDIOVASCULAR JOURNAL OF AFRICA • Vol 23, No 9, October 2012
AFRICA
507
Review Articles
Neo-intimal hyperplasia, diabetes and endovascular
injury
DEIRDRÉ KRUGER
Abstract
Diabetes is a significant major risk factor for peripheral
arterial disease (PAD) and critical limb ischaemia (CLI), the
latter which is also the most common cause of amputation in
these patients. Revascularisation of the lower extremities of
such patients is imperative for limb salvage and has become
first-line therapy. However, the incidence of restenosis follow-
ing endovascular stenting is very high and is largely due to
neo-intimal hyperplasia (NIH), the regulation of which is for
the greater part not understood.
This article therefore reviews our understanding on the
regulation of NIH following stent-induced vascular injury,
and highlights the importance of future studies to investi-
gate whether the profile of vascular progenitor cell differ-
entiation, neo-intimal growth factors and lumen diam-
eters predict the severity of post-stent NIH in the periph-
eral arteries. Results from future studies will (1) better our
understanding of the regulation of NIH in general, (2) deter-
mine whether combinations of any of the vascular factors
discussed are predictive of the extent of NIH postoperatively,
and (3) potentially facilitate future therapeutic targets and/
or change preventive strategies.
Keywords:
neo-intimal hyperplasia, diabetes, critical limb
ischaemia, endovascular stenting, vascular progenitor cells
Submitted 1/6/11, accepted 5/3/12
Published online 22/5/12
Cardiovasc J Afr
2012;
23
: 507–511
DOI: 10.5830/CVJA-2012-019
The World Health Organisation projects that diabetes-related
mortality will double between 2005 and 2030.
1
On the other
hand, the incidence of peripheral artery disease (PAD), which
is usually secondary to atherosclerosis, is expected to rise by
14
to 45% by 2030.
2
Half of the people with diabetes die of
cardiovascular disease, and half of those with diabetes are affected
by diabetic nephropathy. This combination of reduced blood flow
and neuropathy in the feet of diabetics increases the risk of foot
ulcers and eventual limb amputation. Revascularisation in the
lower extremities of these patients is imperative for limb salvage,
which not only improves the quality of life of these patients but
also reduces overall healthcare costs and mortality.
Diabetes and PAD
From the African Program on Genes in Hypertension (APOGH),
the prevalence of diabetes in our local South African setting is
reaching 11% (unpublished data; correspondence with APOGH
principle investigator, Prof Gavin Norton, 3 May 2011). Diabetes
is a significant major risk factor of PAD and critical limb
ischemia (CLI), and its incidence and prevalence is on the
increase due to the aging of the population.
CLI is defined as the presence of gangrene or non-healing
ulceration, rest pain and objective evidence of diffuse pedal
ischaemia. The prevalence of diabetes is particularly high
in patients with CLI, which is also the most common cause
of amputation. Early arterial revascularisation undoubtedly
improves the prognosis in these patients.
3-7
CLI progresses to
gangrene in 40% of diabetic patients compared with 9% of
non-diabetic patients.
8
A large national vascular registry-based survey from Finland
found that diabetes was not an independent risk factor for early
postoperative mortality in CLI, as increased morbidity in diabetic
patients was associated with old age, male gender, known
coronary artery disease, renal insufficiency and, interestingly,
urgent surgery.
6
Be that as it may, limb salvage rates following
superficial femoral artery (SFA) endoluminal interventions are
lower for diabetic patients compared to non-diabetics presenting
with CLI, despite similar patency and restenosis rates.
9
Endovascular interventions of the tibial artery
and CLI
Limb salvage not only improves the CLI patient’s quality
of life, but also reduces his/her mortality rate and lowers
overall healthcare costs.
10,11
As a result, many studies
in the last few years have contributed to the change in
paradigm of surgical revascularisation for CLI and these
endovascular interventions have become first-line therapy
for many surgeons at the femoral and popliteal levels.
12-14
Recently, several studies have reported on the efficacy
of infra-popliteal interventions for the treatment of CLI.
15-17
However, limited data on the efficacy of tibial artery endovascular
intervention (TAEI) in the treatment of CLI, specifically with
regard to limb salvage and wound healing, have resulted
in recommendations for infra-popliteal disease being rather
ambiguous.
18,19
Last year Fernandez
et al
.
reported acceptable
rates of limb salvage and wound healing following TAEI,
18
Department of Surgery, Faculty of Health Sciences,
University of the Witwatersrand, Johannesburg,
South Africa
DEIRDRÉ KRUGER, PhD,
