notes dr Claudio Italiano
The chronic peripheral obstructive arterial disease includes a series of alterations of the large blood vessels, ie the distal arteries, so we do not speak here of coronary syndromes (see angina plaque and cardiovascular risk), but very serious circulatory problems already addressed in the page dedicated to arteriopathy chronic obstructive obliterans of this sitoweb. In the diabetic patient the peripheral ischemic fact becomes even more striking, together with peripheral ischemic neuropathic complications which, intersecting each other, generate the pathology called "the diabetic foot".
As diabetes takes on pandemic proportions, it is crucial for the
orthopedic surgeon to be aware of the issues involved in diabetic foot.
Ulceration is related to neuropathy and to arterial disease, a vital prognostic
factor for healing; infection plays an aggravating role, increasing the risk of
amputation. At-risk feet need to be screened for. Ulcer classification is
essential, to set treatment strategy and determine prognosis. Before any
treatment is decided on, neuropathy, vascular insufficiency and infection should
individually be assessed by clinical examination and appropriate additional
work-up.
Management of diabetic foot remains multidisciplinary. Strategy
notably includes prevention of at-risk foot, revascularization surgery (which
should systematically precede orthopedic surgery in case of critical vascular
insufficiency), and treatment of ulcers, whether these latter are
associated with osteitis or not. Indications for "minor" amputation should be
adequate, and meticulously implemented.
"Acute foot" is a medical emergency, entailing massive empirically
selected I.V. antibiotics to "cool" the lesion. Prophylactic surgery to limit
further risks of ulceration is to be indicated with caution and only when
clearly justified. France urgently requires accredited specialized
multidisciplinary centers to manage severe lesions: deep and infected ulceration,
advanced arteriopathy, and Charcot foot arthropathy.
The fact is that, despite vascular surgery has achieved excellent therapeutic
results with PTA and by-pass, in the patient suffering from diabetic foot
neither one nor the other method are indications because the diabetic arterial disease
inexorably affects the vessels below the knee that become not only calcified
but
also restricted to the maximum and, therefore, it is ultimately impossible to
intervene surgically because if "there is no fabric, nothing is possible to sew!".
Therefore carried out the plethysmographic evaluation and after oxygen perfusion in the periphery with the oximetry technique, it is necessary to evaluate if it is indicated or it is possible to intervene with a by-pass or PTA and stenting, ie enlarging the stenotic arterial vessels or if is indicated a therapy with iloprost.
The use of prostanoids, of these drugs that allow a vasodilation of the bloodstream,
is always recommended in individuals where every other maneuver is impossible
and there is a risk of losing the limb.
- This tratment can reduce:
- The pain of the limb at rest
- Limited trophic lesions (eg diabetic foot and ulcerated lesions often also
infected)
The most commonly used prostanoids are PGE1 and PGI2 or natural prostacyclin and
especially the stable prostacyclin of a synthetic nature or iloprost that in an
observational study of 228 patients with critical lower limb ischemia and
diabetic trophic ulcers and has not shown much more favorable results either in
terms of limb salvage and cardiovascular death reduction compared to those
obtained with PGE1.
Left ischemic lower limb in patient with peripheral
obstructive arterial disease: note the cyanotic color
of the left foot as opposed to the more vascularized right
foot.
Diabetic peripheral arterial disease is a separate clinical picture that derives from the intersection of neuropathic foot and vascular neuropathic foot problems and is frequent in the diabetic, already present in 21% of cases in type 2 diabetes at the time of diagnosis and reaches a prevalence of 50% in patients with long duration of disease, with early and insidious onset but often slow and subtle clinical evolution, the more subtle because the diabetic does not perceive pain in the limbs and the damage occurs when there is nothing left to do. In fact, patients often come to the attention of the diabetologist with trophic lesions to the foot, which actually represent the tip of an iceberg, as underneath the innocent-looking ulcers often hides a very insidious osteomyelitis process, almost always responsible for amputation of fingers or a forefoot or a foot or an entire leg, at worst, when the sepsis has spread and the diabetic foot has become an "acute infected diabetic foot". It is therefore necessary, in the face of these dramatic scenarios, to make a rapid assessment of the case and intervene with vascular surgery where possible, as soon as possible, reserving therapy with iloprost in the other 25% of cases that could not be treated before. It is clear that prostaglandin therapy is not without side effects and that it is also contraindicated in the cardiac patient. Iloprost is an analog of prostacyclin that acts at the level of the microcirculation with a demonstrated antithrombotic activity, pro-angiogenetic and reprogramming of endothelial functions and for this reason it is also used in pulmonary fibrosis, scleroderma and PAD. Furthermore, the ability of the medicament to increase blood flow and restore the physiological balance between endogenous prostanoids and prostacyclin and thromboxane is exploited, which is instead responsible for increased platelet aggregation and thrombus formation (see thromboembolic disease).
Recommendations
All patients with diabetes and CVD should be treated with low doses of ASA. In
diabetic patients with peripheral vasculopathies, treatment should be considered
in some cases with clopidogrel or low molecular weight heparin. The prostacyclin
infusion is an alternative treatment in the patient with critical ischemia of
the lower limb which can not be revascularized.
Treatment of obliterative thromboangiitis (Bürger's disease) in advanced stages
with critical limb ischemia when revascularization is not indicated.
Treatment of Raynaud's phenomenon secondary to scleroderma. Treatment of severe
chronic arterial ischemia of the lower limbs, in patients at risk of amputation
and when surgery or angioplasty is not indicated.
Iloprost must be used under strict medical supervision at adequately equipped
hospitals and clinics. The possibility of an existing pregnancy must be excluded
before treatment of women of childbearing age. It should be administered, after
dilution, by venous infusion. The dosage should be adjusted on the basis of
individual patient tolerability within an infusion range of 0.5 to 2 ng of
iloprost / kg / min. for the duration of 6 hours per day. Treatment will be
repeated daily for a maximum of 4 weeks. In Raynaud's phenomenon, shorter
treatment periods (3 to 5 days) are often sufficient to achieve improvement over
several weeks. The safety and efficacy of a treatment lasting more than 4 weeks
or repeated treatment cycles has not been established. For intravenous use, the
contents of a vial of iloprost must be diluted in 250 ml of sterile saline or 5%
glucose, providing a thorough mixing. The ready-to-use solution thus obtained
containing 200 ng (0.2 mcg) of iloprost / ml will be administered by venous
infusion, daily for 6 hours, in a peripheral vein or via a catheter in a central
vein. by using an infusion pump.
The infusion solution should be prepared daily to ensure sterility. During the
first 2.3 days of treatment, the maximum tolerated individual dose should be
sought. For this purpose the infusion will be started at a rate of 10 ml / h for
30 min. This corresponds to 0.5 ng of iloprost / kg / min. for a 65 kg patient.
There will then be possible increments of an additional 10 ml / h every 30 min.
up to a maximum of 40 ml / h (50 ml / h for patients weighing more than 75 kg).
In the event of the occurrence of side effects such as headache, nausea or
pressure drop, the rate of infusion will be reduced until the tolerated dose is
reached.
If the side effects were high, the infusion could be suspended.