Vascular
disease and diabetes
(Portuguese
PDF version)
Nelson
De Luccia* *
Professor of Vascular Surgery, Department of Surgery, Universidade de São
Paulo. Correspondence:
Dr. Nelson De Luccia
Av. Sã Gualter, 346
CEP 05455-000 - São
Paulo - SP
Tel.: +55 11 3021.0900
E-mail: nluccia@nox.net
J
Vasc Br 2003;2(1):49-60
INTRODUCTION
Diabetes
mellitus affects 2 to 5 % of western populations. However, 40% to 45
% of all lower limb amputees are diabetic. Major amputations are 10
times more frequent in diabetics with peripheral arterial disease than
in nondiabetics with the same condition. Quite often, intermittent claudication
evolves into gangrene in diabetic patients and these are usually submitted
to amputation earlier.1 This picture is
highly correlated with microvascular and macrovascular disease. Understanding
the pathophysiology of these processes is crucial for the treatment
and orientation of these patients.
PATHOPHYSIOLOGY
OF VASCULAR DISEASE IN DIABETES MELLITUS
Many of
the clinical complications of diabetes may be ascribed to vascular disorders,
with consequent lesion to the final irrigated organ and death.
Two types of vascular diseases are specifically observed in diabetic
patients: nonocclusive microcirculatory dysfunction, involving renal
capillaries and arterioles, retina and peripheral nerves, and macroangiopathy,
characterized by arteriosclerotic coronary lesions and peripheral arterial
circulation. Macroangiopathy is a unique symptom of diabetes, while
arteriosclerotic lesions are relatively similar in their morphology
to arteriosclerosis in nondiabetics.2
Despite this similarity regarding the arteriosclerotic process in diabetics
and nondiabetics, several aspects differ and characterize the vascular
diseases of lower extremities in diabetics. In diabetic patients, occlusive
macrovascular disease predominantly involves the tibial and peroneal
arteries, between the knee and the foot, as shown by the fact that diabetic
patients with gangrene have palpable popliteal pulse.3
Foot arteries, especially the dorsalis pedis, among others, are often
spared (Figure 1).
 Figure
1 - Arteriographic aspect characteristic of diabetic macrovascular arteriosclerosis.
Occlusion of truncal leg arteries, with preservation of the terminal peroneal
portion, and filling of the dorsalis pedis artery (arrow).
Due to
the involvement of distal vessels and to the occurrence of nonocclusive
microangiopathy of the kidneys, retina, and peripheral nerves, the etiology
of arteriosclerosis in diabetic patients became known as microangiopathic.
This aspect is especially relevant because, since diabetic arteriosclerosis
was regarded as microangiopathic, these patients were considered for
a long time, and still are by many, unsuitable for arterial reconstruction,
in case of critical ischemia, since they do not have distal bed for
revascularization.4
Compared to other types of arteriosclerotic patients, especially young
smokers, diabetics are potentially more apt for arterial reconstruction
due to the preservation of distal arteries, which allow revascularization
attempts and the salvage of the lower extremities, which would otherwise
be submitted to major amputation.5
This currently well established concept is inserted into a complex context,
as ischemia caused by macrovascular occlusions in diabetic foot patients
is one of the most comprehensive components of a syndrome that also
includes neuropathy and infection.
DIABETIC
MICROANGIOPATHY
The relationship
of microangiopathy with diabetic neuropathy is multiple. The first recognition
of a possible interaction of microcirculation with neuropathy lay in
the description of triple characteristics of long-lasting diabetes,
evidenced by retinal injury, kidney disease and neuropathy. The role
of microangiopathic disorders as etiological factor in the pathogenesis
of diabetic neuropathy has recently come back to the foreground with
the description of the location of endoneural microvascular lesions
in human diabetic neuropathy.6
Although several other theories focused the etiology of neuropathy on
metabolic causes, it is currently accepted that microvascular disorders
are strongly implicated in the etiology of peripheral neuropathy.
Neuropathy is an essential factor for ulceration of nonischemic diabetic
foot, including other components such as high plantar pressure, deformities,
reduced joint motion, and skin dryness. With alteration to or absence
of protective sensitivity, there is formation of calluses in the high-pressure
area, which occasionally ulcerates if no intervention is used to remove
it. The prominence of metatarsals and disorders of the metatarsal heads,
related to the atrophy of the intrinsic muscles, are characteristic
of diabetic ulcerations (Figure 2).
Figure
2 - Typical plantar ulcer on the foot of a diabetic neuropathic patient. Note
that the color of the foot indicates good perfusion. Presence of ulcer with granular
background, which rules out ischemia. 
On the
other hand, other pathophysiological microcirculation disorders are
also ascribed to neuropathy. There is no extant evidence showing clear
contribution of microvascular disease to the development of foot lesions
in diabetic patients. However, studies in this field have produced probable
theories that could explain unclear aspects of these disorders.
Following this line of thought, it is common knowledge that the peripheral
and autonomic nervous systems play a vital role in the control of microvascular
function. The neurogenic mechanisms that regulate microcirculation encompass
generic homeostatic necessities related to functional and metabolic
aspects. There is a sophisticated variety of central and local mechanisms
that regulate the flow of microcirculation under normal health conditions.
In diabetic patients, the microvascular function is altered due to both
structural and functional dysfunction of vessels and to disorders of
regulatory mechanisms.
From the nutritional standpoint, the most important vessels in cutaneous
microcirculation are the superficial capillaries. The exchange of fluids
and solutes passively occurs along the extension of the capillary vessel.
Water filtration primarily depends on the gradient of hydrostatic pressure
through the vessel wall. The exchange of macromolecules predominantly
occurs by the transport of solvents along with the filtered water. Small
exchanges of solutes are highly flow-dependent. Both the pressure and
flow are regulated by changes to the diameter of vessels. The local
changes between pressure and flow at the capillaries are obtained by
the regulation of intrinsic mechanisms that adjust the precapillary
and postcapillary resistance. Precapillary resistance has neurogenic
control and the major local mechanism is believed to involve sympathetic
axonal reflexes. This mechanism relies on the increase of venous pressure,
which distends the veins and induces precapillary reflex vasoconstriction.
This may be shown on the skin and in subcutaneous tissue, restricting
the exposure of microcirculation to the increase of hydrostatic pressure
while the limb is hanging.7
A characteristic disorder that results from these functional and structural
changes to the network of capillaries and arterioles is the thickening
of the basement membrane, smooth muscle cells and endothelial function.
The thickening of the basement membrane may theoretically hamper leukocyte
migration and the response of postlesional hyperemia, thus increasing
the susceptibility to infections.
The normal endothelium plays an important role in vascular function
and in homeostasis, due to the synthesis and release of substances,
such as prostacyclin, endothelin, prostaglandin, and nitric oxide, which
modulate the vasomotor tonus and prevent thrombosis.8
There is some evidence that the endothelial function is abnormal in
diabetics, both insulin-dependent and noninsulin-dependent ones, thus
implicating in hypoglycemia as possible mediator of anomalous endothelium-dependent
responses.9,10
Intrinsic neurological control mechanisms also act on microcirculation
and affect larger changes as to the distribution of blood flow to the
organ, while they simultaneously maintain temperature and arterial blood
pressure. In the periphery, the most relevant function in terms of neuropathy
is the regulation of the arteriovenous communications flow. Arteriovenous
communications are present in the microcirculation of extremities in
large amounts, and are proximal and parallel to the capillaries. The
blood that flows through the arteriovenous communications does not participate
in tissue nutrition and rules any peripheral blood amounts. The relaxation
of sympathetic tonus in response to the increase in central temperature
results in pronounced increase of flow through arteriovenous communications.11
In initial diabetes, the main hemodynamic disorders are functional and
include the increase in peripheral blood flow. This may represent normal
physiological response, with increase in the flow through arteriovenous
communications in order to dissipate the heat produced from increased
metabolism. At the beginning, these disorders respond to better glycemic
control; however, arteriovenous communications are pronounced in the
presence of clinical neuropathy. This pathological increase in blood
flow through arteriovenous communications is attributed to peripheral
autosympathectomy. The consequences of this increase in anastomotic
flow are increase in tissue temperature and increased metabolic demand,
which predispose to the formation of edema with subsequent increase
in tissue pressure, resulting in the deterioration of capillary flow.
Capillary flow may be low in the skin with abnormally elevated temperature,
secondary to the increased flow of arteriovenous communications. In
the foot dorsum, where arteriovenous communications are rare, there
is no evidence of compromised capillary flow.
Some of
these considerations might be only theoretical, but several clinical
situations exemplify these conditions, such as the ones that affect
diabetic foot patients, with the manifestation of Charcot osteoarthropathy
(Figure 3).
Figure
3 - Aspect of Charcot foot deformities, with emaciation and plantar region with
rocker bottom (left); hyperpalpable pulses on examination; radiographic aspect
showing collapse of midtarsal bones (right). 
In general,
in the acute phase, the patient presents with extremely edematous foot,
which compromises the use of common shoes. The whole foot is often erythematous,
hot when touched and shows signs of anidrosis. On examination, the foot
might be roughly deformed, with the classic rocker bottom, due to the
subluxation of midtarsal bones. Temperature gradients with increase
of 2 to 5° C in relation to the contralateral foot are consistently
shown and the pulses are hyperpalpable. Perhaps, this is the most dramatic
manifestation of neuropathy and of the hyperkinetic state of circulation,
which may be explained by the described theories of functional disorders
of microcirculation.
The differential diagnosis with infectious processes must be made. Nevertheless,
the etiology of foot disorders described by Charcot in 1868,12
is purely neurological, once in the original study, they referred to
the complications produced by syphilitic spinal cord injuries. Other
neurological disorders, such as the ones caused by traumatic spinal
lesions, congenital spinal bifid sequelae, Hansen's disease, alcoholism,
produce lesions that are similar to those of diabetic neuropathy. Diabetic
neuropathy, epidemiologically, is the most frequently observed peripheral
neuropathy nowadays. A classical study, conducted with experimental
animals in which spinal injury was provoked, demonstrates the neurological
nature behind severe osteoarticular disorders of the lower limbs.13
The total loss of sensation, proprioception and motor function expose
bones, joints, ligaments and joint capsules to abnormal conditions of
minor and major traumas, without the normal possibility for compensation
and balance, which may explain the situation.
Cases of total joint destruction in bones of diabetic foot diabetic
patients because of neuropathy cause surprise due to their severity
and show how difficult and complex it is to treat these patients (Figure
4).
Figure
4 - Severe disorder of the tibiotarsal joint in diabetic patients. 
Ulcers
and tissue lesions, especially in the presence of sensation loss - a situation
in which the patient increases trauma by walking and treading without feeling
the severity of the problem -have great chances of becoming infected. Several
patients are admitted to emergency services with severe infection, clinical decompensation,
without even knowing that they are diabetic. Large emergency debridements for
removal of necrotic tissues, antibiotic therapy and clinical management are of
paramount importance. Some of these patients have to be submitted to minor or
major amputations, sometimes as the only possible alternative. Such amputations
are necessary due to the extension of tissue damage required to save the patient,
given the deterioration of clinical conditions. This shows that educational campaigns
should be implemented in order to avoid such events.
The theories about
the thickening of the capillary basement membrane and reduction in leukocyte migration,
which decrease resistance to infection in diabetic patients, are well-founded,
but an open wound on which the patient unperceivably bears the weight of his/her
body is reason enough to explain the development of infection (Figure 5). Figure
5 - Necrotic and ulcerated plantar area, deteriorated due to the presence of dorsal
phlegmon, requiring emergency surgical debridement. 
On
the other hand, in addition to lesions to neuropathic feet with normal or increased
perfusion, there are cases in which the major characteristic is tissue ischemia,
due to the consequences of arteriosclerotic arterial occlusion (Figure 6). Figure
6 - Ischemic lesion in diabetic patient. 
This
scenario, characterized by its complexity, labeled as diabetic foot, includes
syndromes with hyperpalpable pulses and increased perfusion, in addition to frank
ischemia, with absence of peripheral pulses and tissue necrosis caused by deficient
perfusion and low supply of oxygenated blood. Other subtleties exist, as patients
with absent distal pulses and neuropathy may present a well-balanced health status,
with no symptoms, due to the compensation that results from collateral circulation.
These patients, when they present with neuropathy-related lesions, that is,
reduction or loss of sensation, they should be carefully evaluated as to the possibility
of wound healing, taking into consideration infection and associated ischemia.
MACROVASCULAR
DISEASE
Diabetes
is an important risk factor for the development of arteriosclerosis,
which is clinically more frequent (5 to 10 times) in diabetics than
in nondiabetics.14
It is commonly agreed that arteriosclerosis in diabetics is more diffuse,
more severe and that it appears at an earlier age than arteriosclerosis
in nondiabetics.15,16 Patients with intermittent
claudication and diabetes have a 35% risk for acute ischemia and a 21%
risk for major amputation, compared to risks of 19% and 3%, respectively,
in nondiabetics.17 Despite the
characteristic involvement of infrapopliteal vessels, the disseminated
occurrence on the arterial tree is quite common, also involving the
abdominal, iliac and femoral aortas.
The calcification of the tunica intima and tunica media (Mönckeberg's
sclerosis) is also characteristic of diabetic arteriosclerosis. This
aspect is mainly observed in dialytic patients with renal insufficiency.
Mural diabetic calcification produces errors in noninvasive diagnostic
tests based on the verification of segmental pressures, since they erroneously
elevate the ankle brachial index. In terms of surgery, calcification
hinders revascularizations and requires changes in suture techniques.
However, the calcification is not necessarily occlusive, as shown in
the example of Figure 7.
Figure
7 - Plain x-ray; calcification of the superficial and popliteal femoral artery
(left), compared with arteriography (right) of the same region, showing patent
artery. 
This aspect,
which precludes functional assessment of ischemia in diabetics, should
be also considered when relative and absolute ischemias are involved.
Patients with disseminated arteriosclerosis of lower limbs, as commonly
observed in diabetics, may not have ischemic signs and symptoms, since
there is collateral circulation. Ischemia may occur due to the aggravation
of arterial occlusion or may be triggered by traumatic wounds, caused
by neuropathy, or as a result of infection. Orthopedic surgeries, which
might be necessary for deformity correction, should consider this aspect
carefully, since surgical procedures involve trauma that may decompensate
ischemia. Thus, the nails and calluses in neuropathic patients with
relatively compensated ischemia, if they result in tissue injury when
treated or cared for by nonqualified individuals, may lead to disastrous
events.
Tests for the estimation of the level of ischemia of the extremities
are highly investigated, so that the healing potential of injured or
infected tissues can be predicted and surgical procedures are performed
in cases of deformity, in which surgical incision may not heal, may
deteriorate or cause lesion.
Infection, another factor related to the transformation of relatively
compensated ischemia into decompensated ischemia due to the increased
demand as against the supply, also represents one of the keystones of
diabetic foot management. Obviously, the treatment of infection requires
drainage, debridement of necrotic tissues and use of appropriate antibiotics.
Diabetic patients, due to the described microangiopathic disorders and
to the thickening of the basement membrane, may have higher susceptibility
to infection, as a result of changes in inflammatory response and leukocyte
migration. However, a well-vascularized diabetic foot can manage infection
and lesions surprisingly well. In patients at risk for limb loss, the
improvement of blood perfusion is a priority so that major amputation
can be prevented. In the absence of ischemia most dressing methods are
successful; in the presence of ischemia, most of them fail. If revascularization
is successful, the foot is often saved; if revascularization fails or
is not possible, the foot is usually lost.18
The usual noninvasive tests for estimating tissue ischemia are: verification
of systolic pressure with Doppler ultrasound, verification of pressure
on the ankle and ankle brachial pressure index, analysis of Doppler
ultrasound waveforms, graphical analysis of pulse volume, verification
of pressure on the toes and transcutaneous oxygen pressure (Figure 8).
Figure
8 - Example of direct verification of transcutaneous oxygen pressure. Electrodes
placed on the chest, medial region of the leg and foot allow direct and comparative
reading of oxygen tension. 
All of
these methods have their limitations, and clinical evaluation, judgment
and experience are still the most important ways to estimate vascular
insufficiency of the lower extremities in diabetic patients.
Patients with ischemic lesions, risk of limb loss and absence of peripheral
pulses based on clinical judgment are referred to angiography for revascularization
planning. Clinical judgment, which is more important than the assessment
of the ischemic nature of the lesion, seeks to determine the patient's
general health status. The indication of arteriographic examination
in patients with abnormal renal function, extremely common in these
patients, represents a decisive step in the estimation of risk/benefit
of revascularization in these patients.
The nature
of arteriosclerotic disease, which likewise affects coronary arteries,
implies cardiac risk, which should be carefully observed before any
surgical plan, as it interferes with global judgment. Electrocardiographic
alterations, relevant history of heart disease or ventricular dysfunction
have to be assessed. Echocardiogram and thallium-dipyridamole scan are
used as complementary tools and may indicate cardiac catheterization
and necessity for coronary revascularization before elective vascular
surgery. In cases of patients under these conditions, but who have tissue
damage and severe ischemia of the extremities, a paradox is often established,
since coronary revascularization is not usually performed due to the
presence of gangrened areas, and sometimes, concomitant infection, which
are therefore a priority. Drug therapy with beta-blockers and statins
has been used in these patients and has reduced the incidence of perioperative
events.19
Renal function must be evaluated and, if the result of the arteriographic
exam is abnormal, we must wait until baseline values are obtained and
should avoid the use of nephrotoxic agents. Chronic renal patients submitted
to dialysis have special problems related to both arterial disease,
usually with intense calcifications, and availability of arterial substitutes,
since the veins of lower and upper limbs might not be available due
to local conditions or dialytic access. Even so, some series recommend
revascularization of the lower limbs in these patients, and also in
nondialytic diabetic patients, with comparable results.20
Anesthesia must be considered on an individualized basis. General anesthesia
with endotracheal intubation, spinal anesthesia or epidural block are
equally safe and efficient, and their choice depends on the circumstance.
The regular monitoring with Swan-Ganz catheter is recommended by some
services for the reduction of complications, especially cardiac ones.4
Postoperative walking, albeit desirable, should be carefully allowed
according to the evolution of debrided areas.
In many situations, an alternative to revascularization attempts for
limb salvage is to perform a primary major amputation to solve the problem
with the ischemic lesion and save the patient's life. Obviously, major
amputation also involves surgery and anesthesia, lasts as long as a
revascularization sometimes, and permanently restricts the patient physically.
Major amputation may be minimized by modern rehabilitation techniques,
but they do not offer the patient as good a quality of life as that
provided by limb salvage.21
In this viewpoint, the only indication to primary amputation is the
extension of necrosis and tissue lesion. Even so, estimating the extent
to which tissue damage caused by ischemia represents impossibility of
functional recovery of the limb requires knowledge about the actual
possibilities of reconstruction and about the functional aspects after
minor and major amputations.
ARTERIOGRAPHY
Arteriography
is still the most effective method for assessing the level of occlusion
of arterial disease of the lower extremities and for planning the treatment.
Color flow duplex scanning and magnetic resonance have been suggested
as substitutes for arteriography; however, the latter is still widely
used and provides a lot more information on the topography of arterial
lesions.
The arteriographic pattern of arterial disease in diabetic patients is quite predictable,
in such a way that it is possible to diagnose diabetes only by way of arteriography
(Figure 9). Figure
9 - Arteriographic pattern characteristic of diabetic patient. External iliac
arteries, common femoral and deep femoral arteries relatively preserved (upper
left). Superficial femoral artery showing several strictures, as well as popliteal
artery above and below the knee joint (left). Occlusion of anterior and posterior
tibial arteries, with preservation of peroneal artery which, through its anterior
and posterior perforating branches, refills the pedal arteries (right). 
Some
important considerations should be made on arteriography. Initially, it is an
invasive exam, due to arterial puncture and injection of a nephrotoxic contrast
medium, which is a worrying issue in these patients with high incidence of renal
insufficiency. Its indication can only be justified in case of preoperative planning,
in patients with severe ischemia. In addition, although it allows some kind of
functional analysis of blood flow, especially if dynamic examination involves
fluoroscopy and assessment of contrast medium flow rate, the images do not permit
estimating the level of functional ischemia of the extremities. In other words,
asymptomatic patients with relatively compensated ischemia may have arteriographic
results that reveal important alterations that are similar to those found in symptomatic
patients. Clinical evaluation by an experienced observer allows correlating occlusions
with symptomatic ischemia and treatment planning.
MODES
OF TREATMENT
Diabetic
arteriosclerosis, although prevalent in the infrainguinal region, tends
to be disseminated. Therefore, interventions in the aortoiliac and femoropopliteal
or distal popliteal territories are common.
Even when we consider some characteristics that are relatively specific to
macrovascular arterial disease in diabetics, all conventional vascular surgery
or endovascular techniques are also used on these patients.
Concomitant
disease in more than one region is frequent and, obviously, proximal flow has
to be adequate so that distal reconstructions work out. These surgical interventions
may be topographically divided into aortoiliac and femoropopliteal, and functionally
classified as supply and flow of oxygenated blood.
Aortoiliac
interventions
Conventional
surgical techniques with the aim of treating arteriosclerotic occlusions
in the aortoiliac region and ensuring supply of oxygenated blood to
the lower extremities include bypass grafts with arterial substitutes
and direct elimination of occlusion by endarterectomy. Sympathectomy,
which indirectly acts on blood supply, is rarely used, due to the nature
of autonomic neuropathy in diabetic patients. The most commonly used
bypass grafts are the aortoiliac and aortofemoral ones, and an alternative
to them includes ilio-iliac, ileofemoral, femoro-femoral, axillofemoral
and axillo-bifemoral grafts. These surgeries are separately considered
according to the necessity of each patient, depending on the site and
extension of the disease and associated risk factors. These procedures,
when performed after careful judgment and followed by adequate perioperative
monitoring, are as safe as major amputations.22
Endovascular interventions, represented by transluminal angioplasty,
with the insertion of balloons, followed or not by insertion of simple
or lined metallic stents (endoprostheses), are also a direct method
for arterial deobstruction. They are usually recommended for focal disease
(distal abdominal aorta, common iliac aorta and external iliac aorta).
For diffuse, extensive and complex disease, at several levels and multifocal,
or for totally occluded segments of the abdominal aortic and iliac aortas,
conventional surgery is the procedure of choice.
Infrainguinal
interventions
The description
of first revascularization in the femoropopliteal region, which showed
the possibility of using the greater saphenous vein as arterial substitute
for bypass graft, made over 50 years ago, established principles that
are, today, totally applicable to the treatment of diabetic foot ischemia.
Kunlin.23 described ischemia in a 54-year-old
patient, who presented with pain, paleness, tissue lesions on foot,
but whose situation was totally reversed, with improvement of symptoms,
reestablishment of perfusion (pink color), and healing of lesions after
repair of distal pulses through successful revascularization.
Currently, the saphenous vein is still the main substitute used in bypass
grafts, which are widely used in this region. The most widely accepted
indication for this procedure is the presence of severe ischemia with
tissue damage, gangrene and risk of limb loss.
However, the disseminated nature of diabetic arterial disease and increase
of longevity of this population, as a result of better clinical management
of the disease, brought about the development of more complex reconstructions
in cases of ischemia presented by patients over the decades.
The possibility of revascularization of infrapopliteal arteries, described
later on,24 allowed better visualization
of distal arteries because of improved angiographic techniques, understanding
of the pathophysiology of diabetic arterial disease (which, although
topographically distal, preserves pedal arteries), and systematic training
in vascular surgery, changed the treatment of diabetic patients and
increased the rate of limb salvage.
Bypass grafts of foot arteries currently represent the need for revascularization25
(Figure 10).
Figure
10 - Control arteriography of femoropedal revascularization (top). Characteristic
path of the vein in the late postoperative period, showing functional graft and
preservation of the extremity (bottom). 
Revascularization
techniques for the infrainguinal and infrapopliteal regions currently
represent a field of growth and challenges as far as surgical techniques
are concerned.
The use of the saphenous vein as arterial substitute is still fundamental
for the success of procedures in this area. The use of this vein has
been broadly discussed in the medical literature: if inverted, the techniques
are used for adjustment of the arterial flow to the physiological position
of valves; if not inverted, maintained in its bed (in situ technique)
or removed from its bed, both situations demand surgical lysis of valves.
The in situ technique successfully described for revascularization of
severe ischemia cases, either in diabetics or nondiabetics, has become
extremely popular, and significant case histories abounded.27
The main objective of this technique is to preserve the endothelium,
in addition to maintaining the proximal and distal diameter of the saphenous
vein compatible with the proximal and distal diameter of the donor and
recipient arteries, since the vein is not removed from its bed, which
would increase the durability of these procedures.
The actual importance of preserving the vein in its bed and of endothelial
protection was however questioned by authors who continued to perform
revascularizations with the inverted technique, with results that resembled
those of the in situ technique.28
For in
situ revascularization to be possible, anatomical conditions have to
be excellent. The saphenous vein must be free of disease and preserved
in all the extension of its bed. These privileged conditions may explain
the good results of the in situ technique. These conditions, however,
are less and less observed.
The use of nonreversed vein with valve lysis, removed from its bed,
has become the routine procedure.5,29,30
The advantageous characteristics of this technique are the following:
(1) it allows selecting the best segment of the vein and makes more
flexible the selection of ideal parts of the donor and recipient artery
for the bypass graft; (2) since it is not inverted, it maintains the
diameter relationship with the arteries; (3) during devalvulation, the
vein is examined by the valvulotome and some inappropriate part of the
vein may be removed; (4) skin lesions may occur in layers. When veins
from the upper limb or from other segments of superficial veins, devalvulation
is also used for the same reasons.31
Patients with previous revascularization of the lower limb or myocardium,
or patients with saphenous vein unavailability (due to phlebitis or
any other condition, such as venous disease, or removal due to venous
insufficiency or varicose veins) are frequently present and, in these
cases, the possibilities of revascularization are more restricted.
Since the functioning of the umbilical cord vein or homologous preserved
veins cannot be yet compared to that of the saphenous vein or other
substitutes for the infrapopliteal region (e.g.: expanded polytetrafluorethylene
(PTFE)), a totally autogenous procedure is recommended by many surgeons.
This way, other superficial veins, as the external saphenous vein, upper
limb veins and deep veins, have been suggested for revascularixations.31-33
However, as these procedures require longer surgical time and multiple
incisions, some prefer to use prostheses. Even so, they are used with
some additional maneuver, such as interposition graft in the segment
of the vein at the distal anastomosis.34
Endovascular therapy for the femoropopliteal and distal region is less
commonly indicated than that for the aortoiliac territory and also requires
long-term observation for the assessment of durability of the procedures.
Especially in distal leg arteries, its indication is limited due to
the common nature of diabetic lesions, which do not tend to be focal.
Nevertheless, as the variable presentation of arteriosclerotic lesions
is the rule, increasingly more cases have been initially treated with
angioplasty, which may be valid in case of delimitated lesions (Figure
11).
Figure
11 - Patient with stenosis of the posterior tibial artery (A). In (B), passage
of guidewire and in (C), inflated balloon. In (D), contrast medium control injection,
showing result of dilation, with guidewire still in place. 
Aside from
the complex revascularizations described, the possibility of cutaneous
and muscle lining with microsurgical techniques represents another management
alternative.
The example
in Figure 12 shows a patient with extensive lesion to the calcaneal
region, where lining with microsurgical remnant from the abdominal rectum
was used. The patient's limb was preserved and walking ability was recovered
with appropriate footwear.
Figure
12 - Initial aspect after revascularization and initial debridement (top); healing
with microsurgical remnant (right). Control arteriography (bottom), showing epigastric
artery used for remnant irrigation (arrow). 
CONCLUSIONS
AND COMMENTS
Services
that systematically employ distal revascularizations, with due precautions,
have managed to reduce the rate of amputations, with rates of graft
patency of approximately 80% in up to 50 months of follow-up and perioperative
mortality rates around 3%.2
These excellent results are not easily achieved, though. Patients who
require this type of treatment in our setting are not always hospitalized
so soon as to avoid major amputation. At emergency services, a horde
of patients with diabetic foot, neuropathy, infection and ischemia awaits
treatment.
Although medical practice has allowed a lot of improvement, educational
programs should be implemented for the prophylaxis of this worldwide
problem whose incidence is alarming in our setting.
Vascular surgery as a medical specialty, including not only the treatment
of ischemic patients, but also of other surgical emergencies, represented
by abscess drainage, debridements, amputations or prophylactic surgeries
for deformity correction are very helpful in this field. Foot care with
the use of appropriate shoes and prophylactic devices should be encouraged
for prevention of diabetic foot.
In case of major amputations, if they are unavoidable, a reconstructive
and conservative approach to ablation and positive attitude towards
the referral for rehabilitation should be adopted. Thus, after all possibilities
have been analyzed, including the potential for postamputation rehabilitation,
a critical judgment about the indication of revascularization and the
limb salvage, may be made, especially when partial amputations of the
foot (which are still performed in an unsatisfactory fashion) are concerned.
Many challenges have to be overcome so that the feet and vital organs
such as the heart, kidneys, and eyes, also affected by diabetes, receive
due attention and so that this dire scenario can be turned around.
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