Whither the diabetic ischaemic foot?
Mike Edmonds |
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| The diabetic ischaemic foot remains a major challenge. How should it best be managed and where it should be managed? What is the ideal form of organisation of care? The following article reflects the author’s views. What are yours? |
Whither the diabetic ischaemic foot?
Ischaemic foot problems are best treated in multidisciplinary foot clinics where the vascular surgical service should provide
physiological and radiological investigation, angioplasty and proximal and distal revascularisation.
An improved understanding of the pathophysiology of the diabetic ischaemic foot provided the initial rationale for an
active approach towards revascularisation and the advent of new procedures.
Notably angioplasty and bypass of the arteries below the knee made it possible,
supported by increasingly sophisticated arterial imaging techniques such as Duplex and magnetic resonance arteriography.
It was previously thought a microangiopathic arteriolar occlusive disease was responsible for tissue necrosis in the diabetic foot and by implication revascularisation was not useful. It is now considered that tissue necrosis results from poor tissue perfusion that is caused by narrowing and occlusion of the arteries of the leg in particular the arteries below the knee although this is often complicated by a septic occlusive vasculitis of the digital arteries. The practical implication of such a new understanding was that the two important pathologies namely occlusive tibial disease and infection were in reality amenable to treatment thus cure.
Catheter-based revascularisation by means of angioplasty had a major impact in the diabetic patient when its use was extended from
the iliac and femoral arteries to those arteries below the knee utilising very narrow catheters originally developed for the
coronary arteries. Such endovascular procedures have been shown to be feasible and successful in the tibial and peroneal arteries of
the diabetic patient.
More recently, subintimal angioplasty has been used to recanalise long arterial occlusions in the tibial arteries.
Angioplasty must be applied when tissue loss is not extensive and when arterial stenoses and occlusions are still suitable for this
procedure.
Furthermore, angioplasty has become an important part of the management of the ischaemic foot that has become infected.
The diabetic ischaemic foot commonly presents in this way and needs aggressive antibiotic treatment and possible surgical debridement,
as well as optimal tissue perfusion to survive.
However, patients may present late when there is considerable tissue loss, often secondary to infection, accompanied by extensive occlusive arterial disease, which is not amenable to angioplasty.
In these circumstances, distal arterial bypass, in particular to the dorsalis pedis artery, which may be relatively spared, has been established as a valuable procedure in conjunction with surgical debridement, adjunctive plastic surgery and antibiotic therapy.
Diabetic ischaemic foot patients with end-stage renal disease are the most difficult to treat because of the presence of diffuse disease,
greater involvement of the distal and pedal vessels, and extensive tissue necrosis.
However, bypass can be performed safely and effectively in patients who have undergone renal transplantation
and in a dialysis-dependent patient population.
Angioplasty and bypass should not be regarded as competing treatments but as complementary.
It is important that they are each applied in a timely and appropriate manner within the organisational
framework of a weekly joint vascular clinic attended by vascular surgeon, diabetologist, podiatrist and nurse and a vascular
radiology meeting also attended by the interventional radiologist and vascular laboratory scientist.
Angiograms are reviewed and joint decisions made as to the suitability of angioplasty,
(which is now often performed as a day case procedure) or alternatively arterial bypass after due review of the patient’s co-morbidities.
After either procedure, patients are followed up closely in the diabetic foot clinic to assess the clinical outcome and the need for further intervention.
These patients are the most complex of diabetic patients with a high mortality and the diabetic foot clinic should take them
on for life to co-ordinate their revascularisation procedures, aggressively treat their infections and manage their co-morbidities
within a multidisciplinary forum.
Mike Edmonds
Consultant Physician and Honorary President of FDUK
January 2007