1.Basic concepts
1.1 The difference between diabetic lower extremity ischemia and lower extremity atherosclerosis combined with diabetes is no essential difference between the two, there are two phenomena, namely diabetes and atherosclerosis. Only the sequence of lesion occurrence is different. Atherosclerosis is one of the manifestations of lipid metabolism disorder. If diabetes mellitus is combined with this, there is a disorder of glucose metabolism at the same time. Naturally, it will aggravate the lesion of atherosclerosis; the opposite is also true.
1,2 Diabetic foot and diabetic lower limb ischemia
The concept of diabetic foot was first introduced by Oakley in 1956, and was defined by Catterall in 1972 as a foot with loss of sensation due to neuropathy and loss of vitality due to ischemia, combined with infection.
The WHO definition is foot infection, ulceration and/or deep tissue destruction associated with distal nerve abnormalities and varying degrees of peripheral vasculopathy in the lower extremities. As the understanding of diabetic foot has advanced. It is found that diabetic foot is a group of syndromes of the foot, not a single symptom.
It should have at least the following elements: first is a diabetic patient. The second is that there should be trophic disorders of the foot tissue (ulcers or gangrene), and the third is accompanied by certain nerve or (and) vascular lesions of the lower extremities, one of the three cannot be absent, otherwise it cannot be called a diabetic foot.
Diabetic foot is generally divided into three types, namely neurological, ischemic and neuroischemic (also called mixed type). At present, the diabetic foot in China is mainly of the mixed type, followed by the ischemic type, while the pure neurological type is relatively rare. Diabetic lower limb ischemia is due to the simultaneous development of lower limb arteriosclerosis and occlusion in diabetic patients, regardless of the sequence of occurrence of the two, as long as these 2 factors are present, it is called diabetic lower limb ischemia.
The clinical manifestations of diabetic lower extremity ischemia are basically similar to those of lower extremity ischemia caused by simple atherosclerosis, but the symptoms and signs of the former are more serious. The main manifestations are early ischemic symptoms, numbness of the foot, cold skin and pain only after activity, i.e., intermittent claudication; the compensatory phase in the middle stage, i.e., resting pain in the foot; and the tissue defects in the late stage, mainly including foot ulcers (even ulcers with infection) and partial tissue gangrene of the foot (even gangrene and with infection).
1.3 Definition of amputation
Amputation is defined as the removal of the distal end of 1 limb according to the International Clinical Guidelines for the Diabetic Foot. Repeat amputation: A previous amputation that has not healed and another amputation starting from the distal end. New amputation: Healing of the affected area from a previous amputation followed by amputation from the distal end. Minor amputation: Joint disarticulation at and below the level of the ankle joint. Major amputation: Amputation above the level of the ankle joint.
2.Epidemiology of diabetic foot
2.1 Foreign epidemiology
(1) Among all non-traumatic low amputations, diabetic patients account for 40% to 60%.
(2) Among diabetes-related low distal amputations, 85% occur after foot ulceration.
(3) Among diabetic patients, 4 out of 5 ulcers were induced or worsened because of trauma.
(4) The prevalence of foot ulcers among diabetic patients is 4% to 10%.
2. 2 Domestic epidemiology
(1)The multicenter data in China was 19.47% of lower limb arteriopathy in diabetic population over 50 years old.
(2) The proportion of lower extremity arterial lesions in diabetic population over 60 years old was 35.36% in a single-center study III.
(3) The incidence of lower limb vasculopathy in type 2 diabetes in a multicenter study in Beijing was as high as 90.8%. Among them, 43.3% were severe or above.
(4) The lesions of both lower limbs in diabetic patients develop symmetrically.
3.Diabetes and peripheral vascular lesions
3.1 Relationship between vascular factors and diabetes mellitus
(1) Peripheral vascular disease is the most important factor affecting the prognosis of diabetic foot ulcers.
(2) Peripheral vascular lesions can usually be detected by simple clinical examination: skin color and temperature, dorsalis pedis artery pulsation, and ankle blood pressure measurement.
(3) The probability of healing of diabetic foot ulcers can be assessed using non-invasive vascular examinations. Ankle and occasionally toe blood pressure measurements may show inaccurate assessment results due to calcification of the middle layer of the artery.
(4) Resting pain due to ischemia may disappear in diabetic patients due to combined peripheral neuropathy.
(5) Microangiopathy is not a major cause of foot ulcers.
(6) Conservative treatment measures include a walking program (if no foot ulcer or gangrene is present), proper footwear, smoking cessation, and aggressive treatment of hypertension and hyperlipidemia.
(7) After revascularization. Revascularization rates and limb salvage rates do not differ between diabetic and non-diabetic patients.
Therefore, diabetes is not a reason to refuse revascularization. Atherosclerosis in diabetic patients mainly includes atherosclerosis and mesothelial arteriosclerosis. The ischemia caused by the former is due to narrowing and blockage of the arteries: the latter is caused by calcification of the middle layer of the arteries that makes the vessels form a hard tube. Thus, arteriosclerosis does not cause ischemia, but hardened arteries severely interfere with the indirect measurement of arterial blood pressure. Microangiopathy is not a major cause of skin damage.
3,2 Characteristics of diabetic vasculopathy
In the International Clinical Guidelines for the Diabetic Foot, the following characteristics of atherosclerosis in diabetic patients compared to non-diabetic patients are specified.
(i) It is more common.
② younger age of onset.
(iii) No gender differences.
④ lesions occurring in multiple segments.
⑤ lesions occur more distally (aorta a iliac artery is hardly involved).
Similar characteristics have been found in our domestic study.
4, the prognosis of diabetic foot
In a prospective (multicenter) study of 1107 patients with diabetic lower extremity ischemia conducted by a scientific group in Italy over a period of 8 years, the final outcome of the patients was ulceration, amputation and death.
The factors that determine the prognosis of diabetic foot ulcers are complex, and early and effective treatment determines the prognosis, so we must pay attention to it.
5.Treatment
The traditional view is that diabetic foot is generally divided into neurological, ischemic and mixed types. In the past, it was thought that the national diabetic foot was mainly of the neurological type, however, a study found that the diabetic foot was mainly of the mixed type, followed by the ischemic type, while the pure neurological type was relatively rare.
There is a lack of effective treatment for neurological lesions, while for ischemic lesions, blood flow to the lower extremities can be reestablished. Most patients can be treated with some success: even in mixed lesions. If the blood flow is successfully reconstructed. The neuropathy can also be partially relieved. Of course, in the treatment of diabetic foot, comprehensive treatment should be emphasized. The idea that diabetic foot is a medical disease and can be treated conservatively by internal medicine, or a surgical disease and can be solved by surgical treatment is a narrow-minded performance.
The six-ring method of “improving circulation, controlling blood sugar, anti-infection, local debridement and drug replacement, nerve nutrition and supportive treatment” proposed by the Air Force General Hospital is a very good measure. On top of this, we should add
①Control the cause of the disease, such as lowering blood pressure, lowering lipids and quitting smoking, if the cause of the disease is not removed, the lesion continues to develop, the treatment effect will be poor.
② Amputation (toe amputation), when gangrenous lesions have already occurred, amputation is still a wise choice.
In any case, however, the reconstruction of arterial blood flow to the lower extremities is the most important and critical measure in the treatment of diabetic lower extremity ischemia.
5.1 Reconstruction methods of lower limb blood supply
Comprehensive various methods of treating lower extremity ischemia at home and abroad. There are several kinds as follows.
5.1.1 Specific methods of lower extremity arterial endoluminal intervention include percutaneous puncture intra-arterial molding (mainly referring to simple balloon dilation) and direct arterial endoluminal stenting on the basis of balloon dilation. As a minimally invasive means, it can be preferred especially when the patient is old and frail or with other diseases that cannot tolerate arterial bypass grafting.
5.1.1.1 Indications for lower extremity arterial endoluminal intervention.
(i) Having good arterial flow pathways and outflow tracts.
(ii) Unable to tolerate the procedure due to old age and frailty, combined with other diseases.
③ Although the arterial outflow tract is poor, it can be considered when there is a limited lesion (stenosis or occlusion) in the proximal segment.
5.1.1.2 Efficacy evaluation.
If the intervention is successful, the general symptoms can be relieved or improved. Current evaluation indicators include subjective and objective indicators. The former includes the improvement of subjective symptoms, such as the relief or reduction of pain and improvement of cold sensation in the limb; the latter includes the ankle brachiM index (ABI), the healing of the ulcer surface, and the reduction of the amputation plane. For diabetic patients with lower limb ischemia, clinical success is considered as long as 1 index is improved.
5.1.2 There are two main traditional methods of lower limb arterial bypass grafting for diabetic lower limb ischemia. One is the most commonly used femoral artery-above-knee or below-knee rouge artery bypass grafting, which is one of the most common procedures in vascular surgery, especially the femoral artery-above-knee rouge artery bypass grafting, which can be done by almost all vascular surgeons at present. The other is the distal lower limb small artery bypass graft, which is a more difficult procedure because the most distal anastomosis of the lower limb artery graft is anastomosed on the calf artery or the foot artery.
5.1.2.l Indications for arterial bypass grafting.
① relatively good arterial outflow tracts in the distal part of the lower limb.
② The patient is in good physical condition and can tolerate the procedure.
5.1.2.2 Efficacy evaluation.
Basically, the evaluation is similar to that of the lower extremity arterial endoluminal intervention. It is important to emphasize that due to the high surgical trauma, caution should be exercised in patients with concurrent severe cardiovascular or cerebrovascular diseases or other diseases, and either lower limb arterial endoluminal intervention or other measures can be chosen. in order to avoid a successful surgery with life sacrifice or causing other serious consequences.
5.2 Autologous Stem Cell Transplantation
Autologous stem cell transplantation is a new technology developed in recent years. It is not yet popular in China, and conditional units can decide whether to choose it according to the situation. Stem cell transplantation generally uses bone marrow blood, peripheral blood, umbilical cord blood and embryonic stem cells. Currently, bone marrow blood and peripheral blood stem cell transplantation are mainly used in clinical practice. Vascular surgery mainly uses autologous stem cells to treat lower extremity ischemia. Autologous stem cells have at least 2 advantages: (1) no immune rejection; (2) no ethical and moral issues with embryonic stem cells.
How to choose the treatment
It is also a challenge to choose the treatment for diabetic lower limb ischemia and to evaluate the efficacy in clinical practice. Because, the treatment method is inappropriate, it will affect the efficacy. The general principle of selecting treatment should be that the choice is based on the patient’s condition needs, not on the physician’s personal mastery. The following are the principles for the selection of methods to treat diabetic lower extremity ischemia.
5.3.1 Endoluminal intervention or arterial bypass grafting or both for lesions in the large arteries (abdominal aorta, iliac artery). The specific choice can be based on the patient’s physical condition and economic status. If the patient is in good health and is young (<70 years old), arterial bypass graft or intervention can be chosen, or hybrid surgery, i.e. intervention and arterial bypass graft can be applied simultaneously; if the patient is weak and old, and also has other diseases, intervention can be chosen.
5.3.2 Interventional or arterial bypass grafting or both applied simultaneously for medium artery (femoral artery, rouge artery) lesions, or autologous stem cell transplantation.
5.3.3 Small artery (calf artery or foot artery) lesions intervention or arterial bypass grafting or both applied simultaneously, or autologous stem cell transplantation. Unlike femoral artery and rouge artery, small artery intervention can be chosen: autologous stem cell transplantation can also be preferred and is generally more effective, especially after bone marrow stem cell transplantation after bone marrow stimulation.
5.4 Perioperative treatment
No matter what treatment method is used. All should pay attention to the perioperative treatment. It not only has a direct impact on the treatment effect, but also affects its long-term efficacy. At present, the following measures are mainly available.
5.4.1 Anticoagulation treatment In patients with diabetic lower limb ischemia, a lot of blood is in a hypercoagulable state, and anticoagulation measures can be used to prevent thrombus formation.
5.4.2 Anti-platelet therapy Stop platelet aggregation to prevent thrombosis.
5.4.2 Vasodilators The purpose of vasodilators is to reduce peripheral vascular resistance, prolong the patency time of graft vessels, percutaneous transluminal angioplasty or (and) stents, and facilitate stem cell differentiation.
5.4.3 Fibrinogen-lowering therapy Fibrinogen is often higher than normal in patients with diabetic foot, so fibrinogen-lowering therapy is particularly important.