What is a diabetic foot?
A diabetic foot is a serious ulcer and gangrene of the foot that occurs as a result of diabetic peripheral vascular disease and peripheral neuropathy combined with infection. Previously, due to the difficulty of treatment, it caused great physical and mental pain to the patient, and in severe cases, it may even lead to the fate of eventual amputation.
How is the diabetic foot treated?
Traditional treatment of diabetic foot includes aggressive blood sugar control, giving wound dressing changes and systemic antibiotics. However, since the underlying blood flow problem is not well addressed, the treatment effect is hardly satisfactory, and the treatment time is long and costly.
New treatment methods for diabetic foot
For the characteristics of vascular disease of diabetic foot, vascular surgery performs balloon dilatation technique of infrapopliteal artery, combined with stenting technique, and also performs surgery or endoluminal minimally invasive treatment at the same time for arterial occlusive disease in other parts of the patient’s body that may be combined, which can achieve very satisfactory treatment results. For patients with complete vascular occlusion below the knee joint, autologous or embryonic stem cell transplantation techniques can also be used. This treatment is very effective in relieving the patient’s ulcerative or gangrenous lesions and creating conditions for limb preservation, which will fundamentally improve the prognosis of the diabetic foot.
Why diabetic patients are prone to develop diabetic foot
Diabetic patients are prone to these pathological changes mainly because of.
1. Peripheral vasculopathy in diabetes mellitus.
Peripheral vasculopathy in diabetic patients mainly refers to lower limb vasculopathy. A large amount of information has long confirmed that in diabetic patients, due to disorders of sugar, fat and protein metabolism, atherosclerosis occurs in the walls of their arteries 10-15 years earlier than in normal people; plaque formation can be seen in the walls of the blood vessels where the lesions occur, and lipids such as cholesterol are deposited in the plaques, narrowing and blocking the blood vessels. Since blood carrying oxygen is circulating in the arteries, if the blood vessel supplying an organ or tissue is narrowed, the supply of oxygen to that organ or tissue is seen to be lacking, and clinical symptoms are seen only when the vessel is narrowed to 3/4. However, it takes about 10 or even 20 years for the stenosis to become severe (3/4). If the patient’s blood glucose control is not up to standard, the lesion of the blood vessel wall proceeds silently, and during this rather long period of time, the patient does not feel anything himself, and by the time he has symptoms, he is already in an advanced stage. Therefore, if a diabetic patient’s blood sugar control is not up to standard it is costly.
In diabetic patients, occlusive vasculopathy of the lower extremities is mostly seen in the anterior tibial, posterior tibial and peroneal arteries, and in non-diabetic patients, it is mostly found in the iliac aorta and femoral artery. The incidence of occlusion of the metatarsal artery and toe artery in diabetic patients is 65% and 20%, respectively, while in non-diabetic patients it is only 19% and 8%.
2. Lower extremity neuropathy in diabetes mellitus.
Lower limb neuropathy is caused by hyperglycemia. Lower limb neuropathy can make the foot pain, touch and temperature sensation weaken or disappear, such that the skin is prone to various traumas, ulcer formation and infection. Loss of deep sensation can cause injury, osteolysis and destruction of the bones and joints of the foot. Motor neuropathy can lead to muscle paralysis and atrophy, causing foot deformity. Deformed feet are easily damaged.
Almost all poorly controlled diabetic patients with hyperglycemia have mild nerve conduction disorders, but they are often asymptomatic. The first symptoms are often numbness, pins-and-needles pain, ankylosis and other sensory abnormalities in the lower extremities. As the disease progresses, the sensation of touch, pain, temperature, vibration and finally tendon reflexes disappear. The involvement of motor nerve causes the foot muscles to lose their balance of extension and flexion, resulting in claw-like toes and high arched feet.
The deformed foot puts significant pressure on the protruding metatarsal heads during walking. In normal people, the weight-bearing support points for the palm of the foot during walking and standing are the heel of the foot and the first and fifth metatarsal heads. In high arched feet and claw toes, the protruding metatarsal heads become the main weight-bearing support points on the bottom of the foot. Due to loss of pain sensation and overload and friction, the skin on the palmar side of the protruding metatarsal head becomes hyperkeratotic and thickened. A large callus is formed. Such a callus is very hard and is prone to subcutaneous bleeding or blistering, and eventually an ulcer is formed under the callus. Its compressed subcutaneous tissue is particularly susceptible to bacterial infection, and an abscess soon forms. Abscesses that penetrate superficially into the skin can drain on their own, but they can also easily spread deeper into the bones and joints, forming arthritis and osteomyelitis. Superficial neuropathic ulcers are often painless, but pain begins when the infection extends to the bones.
3. Diabetic patients are prone to complications of infection.
(a) When diabetes treatment is not up to standard, the resistance is weakened due to disorders of carbohydrate, protein and fat metabolism in the body, while high blood sugar favors the growth of certain bacteria.
A lower than normal blood killing capacity and bacteriocidal capacity.
diminished ability of the tissues to respond to foreign stimuli (e.g. antigens).
weakened tissue cell nutrition and poor local resistance.
Poorly controlled diabetes mellitus, susceptible to vasculopathy, susceptible to infection when blood circulation is impaired, and when circulation impairment is very severe, poor tissue oxygenation and susceptible to anaerobic bacterial growth, sufficient to cause tissue necrosis and gangrene.
Why diabetic chronic lower extremity ischemic ulcers are less painful
Diabetic chronic lower extremity ischemic lesions are usually not simply lesions of occluded or narrowed blood vessels, but mostly combined with diabetic microangiopathy, diabetic peripheral neuropathy and diabetic skin lesions, which involve a variety of tissues, making the presentation of the condition more complex. Usually, diabetic peripheral neuropathy and dermatopathy involve sensory nerves first, which manifests itself in the late detection and slower detection of changes such as pain and coldness in the lower extremities than in normal patients, and even ischemic ulcers, which are usually painful, may not be too painful.
Progress and evaluation of surgical treatment of diabetic foot
Diabetes is a common disease, and the number of cases is increasing every year. There are approximately 800,000 new patients each year in the United States, ranking it as the seventh leading cause of death. Diabetes can lead to peripheral neuropathy, fundopathy, nephropathy, and narrowing or occlusive lesions of peripheral arteries (including heart, brain, and peripheral arteries), and diabetes eventually presents with peripheral arterial disease (PAD) two to four times more often than normal. According to statistics, about 20% of diabetic patients in the United States may develop diabetic foot ulcer formation each year, and amputations due to diabetic foot account for more than 50% of non-traumatic amputations, of which 30% require amputation above the thigh, and 50% of those patients who already have one lower limb amputated will eventually lose the opposite limb. Especially in patients with combined lower limb atherosclerosis-occlusive disease, if combined with diabetic peripheral vasculopathy, 50-70% require surgical treatment; in contrast, in patients without diabetes, this figure is only 20-40%. Therefore, surgical treatment of the diabetic foot has become a clinical challenge of widespread interest to vascular surgeons.
Comprehensive treatment strategies for the diabetic foot
Although the pathological changes of the diabetic foot include neuropathy, vasculopathy, and foot ulceration and infection, most scholars still consider tissue ischemia caused by peripheral arterial stenosis and occlusion as the main cause and hazard of the diabetic foot. Therefore, the treatment of lower extremity ischemia has been the focus of diabetic foot treatment.
The current surgical treatment for diabetic foot vasculopathy mainly includes three aspects, such as pharmacological treatment, surgical treatment and endovascular treatment.
1, drug therapy: for the diabetic foot drug therapy, the first is the treatment of diabetes and active control of blood sugar. Diabetic patients often have hypertension, hyperlipidemia, atherosclerosis, etc., and should be actively treated and controlled various related risk factors. The main pharmacological treatment for vascular lesions is the application of vasodilators and antiplatelet agents, of which antiplatelet agents have received widespread attention. A controlled study of more than 6,000 patients with peripheral vascular disease using Povidon and aspirin showed that Povidon was significantly better than aspirin in reducing heart attacks, ischemic strokes and vascular-related deaths, etc. The US FDA recommends Povidon as the drug of choice for reducing ischemic events in patients with PAD, and the TASC (TransAtlantic Inter-Society Consensus. The TASC (TransAtlantic Inter-Society Consensus) recommends PEDA as an effective drug for the treatment of lower extremity ischemia. In addition, the treatment of wounds is mainly wound debridement and dressing, local application of blood-vitalizing and vasodilating drugs, but the blood flow to the wound site is not effectively improved, and the local ulcer is difficult to heal, and even easily combined with infection, aggravation of the ulcer or even gangrene requiring amputation. Therefore, in addition to pharmacological treatment and local debridement and dressing exchange, the most critical treatment for diabetic foot is to rapidly improve and enhance the blood supply to the affected limb, increase the tissue supply, improve the tissue resistance to infection and healing ability, and promote the healing of ulcers and wounds. Therefore, the treatment for diabetic vascular lesions should focus on the reconstruction of arterial blood flow to achieve the purpose of rapidly restoring blood flow to ischemic tissues.
2.Surgical treatment: Surgical treatment is mainly applied to patients with diabetes combined with lower extremity atherosclerosis occlusive disease with large and medium vessel involvement and TASC grade C,D lesions. Because diabetes and atherosclerosis are closely related, patients with diabetic foot can often have combined iliac and femoral artery stenosis or occlusion. Diabetic patients with lower extremity artery occlusion may have more ischemic symptoms in the affected foot, so it is important to re-establish arterial flow in the lower extremity.
(1) Currently, the treatment of iliac artery lesions is mainly endovascular treatment, including balloon dilation, stent implantation, and subintimal angioplasty, etc. Endovascular treatment can avoid open surgery, is less invasive, has faster recovery, and has a long-term patency rate that is basically the same as surgical treatment, and has become the main means of treating iliac artery stenosis and occlusion. And for femoral? artery (TASC grade C, D) lesions, the treatment is mainly based on autologous vein bypass or artificial vessel bypass.
(2) Autologous saphenous vein bypass, including in situ vein bypass and to placed saphenous vein bypass. It is generally believed that as long as the saphenous vein is in good condition, it should be used as the first graft material. However, there is a problem of limited access to the autologous vein, and autologous vein access is relatively more invasive, with the possibility of complications such as poor wound healing. Most scholars currently believe that the long-term patency rate of autologous saphenous vein bypass is superior to that of artificial vessels. However, a prospective study by Ballotta showed no statistically significant difference in the 1-, 3-, and 5-year patency rates between PTFE prosthetic and autologous suprapatellar saphenous vein bypass. 79.5%, with no statistically significant difference. According to our experience, regardless of the type of graft material selected, the main factors affecting the near-term (within 30 days) patency rate are the condition of the patient’s vascular inflow and outflow tracts, perioperative anticoagulation measures and the surgeon’s technical operation, while the main factors affecting the long-term (>90 days) patency rate are the progression of atherosclerosis, the restenosis of the endothelium of the anastomosis and the progression of the atherosclerotic lesion.
(3) Artificial vessel bypass, mainly using PTFE material artificial vessel to perform femoral artery bypass, is suitable for self-induced artery bypass.
arterial bypass, which is suitable for patients with poor autologous vein conditions, the presence of varicose veins or saphenous veins that have been removed. It is generally believed that the 2-year patency rate of superior knee bypass with PTFE artificial vessels can reach or approach 70%-80%, while the infrapopliteal patency rate is very low, only 30%-40%, but the composite bypass with distal artificial vessels combined with veins can increase the 2-year patency rate to more than 50%. In recent years, heparin-coated polyester vessels have been used in clinical practice, and their long-term patency rates are significantly better than those of PTFE artificial vessels. The author experiences that the softness of this heparin-coated vessel and the suture needle feel good, the needle hole is not easy to leak blood, the recent effect is satisfactory, but its long-term patency rate needs to be further confirmed.
3.Endovascular treatment.
At present, clinical endoluminal treatment is mainly based on balloon dilation and stent implantation, although there are also reports of laser and rotary cutting and other techniques applied in clinical practice, but they have not been commonly carried out yet. From the perspective of evidence-based medicine, it is now agreed that endoluminal balloon dilation and stent implantation are more effective than arterial bypass surgery for TASC grade A and B knee lesions, while endoluminal treatment is less effective for TASC grade C and D lesions. Surowiec et al. reported patency rates of 86%, 80%, 75%, 66%, 60%, 58%, and 52% at 3, 6, 12, 24, 36, 48, and 60 months after superficial femoral artery stenting, respectively; Galied summarized data on the luminal treatment of a large number of lower extremity arterial occlusions, including 923 balloon dilation and 473 stenting cases, in which the 3-year patency rate for balloon dilation was 61% for stenotic lesions and 48% for occlusive lesions. The 3-year patency rates for stenting were 63% and 66% for occlusive lesions, 43% for severe stenotic lesions, and 30% for severe occlusive lesions. The patency rate of lower extremity artery stenting is closely related to lesion grading, and it is generally believed that stenting is mainly used for cases with post-dilatation entrapment, and those with post-dilatation patency without entrapment can undergo balloon dilation alone without stenting. However, the results of a recent well-designed prospective clinical study showed that the long-term patency rate of stenting for lower extremity arterial stenosis was significantly better than that of balloon dilation alone, with statistical differences.
The treatment of infrapopliteal arterial lesions has been a clinical challenge for vascular surgeons. In the past, inversion or in situ grafting of the infrapopliteal saphenous vein was mainly used, but the long-term patency rate and limb salvage rate were not satisfactory and more invasive. In recent years, balloons and stents for endovascular treatment have made great progress, for example, a special long balloon produced by Intec, Italy, has been used for the clinical treatment of diabetic foot infrapopliteal artery stenosis with good clinical results. a multicenter prospective clinical study conducted by Faglia et al. on 221 patients with diabetic foot ulcers showed that PTA could promote foot artery reconstruction and lateral branch The establishment of circulation, reduction of amputation plane, and repeatable operation with few complications recommended that PTA should be the treatment of choice for diabetic infrapopliteal artery stenosis. Since 2005, the Department of Vascular Surgery of Peking Union Medical College Hospital has carried out clinical studies on the endoluminal treatment of diabetic infrapopliteal vascular lesions, and the patients were grouped according to the TASC classification criteria for corresponding treatment. All of the selected cases were severe diabetic patients with severe resting pain and limb ulcers. To date, more than 30 cases have been treated and the work is ongoing. To date, the technical success rate is 93% and the limb salvage rate is 97%. Clinical follow-up revealed that the restenosis rate after balloon dilatation of the infrapopliteal artery was high, with a restenosis rate of >50% at 6 months of nearly 30%, but the ulcer of the affected limb had healed and the clinical symptoms disappeared. We believe that balloon dilation treatment for diabetic foot infrapopliteal vasculopathy can rapidly improve the blood supply to the limb and win time for the healing of the affected foot ulcer and toe amputation wound, and the restenosis after balloon dilation is a gradual process, with the gradual formation of restenosis, the lateral circulation of the limb is also gradually compensated and established, which is the clinical significance and value of balloon dilation treatment, and is the key point that the limb saving rate is much higher than the vascular patency rate. This is the clinical significance and value of balloon dilatation therapy, which is the key point that the limb salvage rate is much higher than the vascular patency rate; balloon dilatation is repeatable and can be re-dilated for restenotic lesions, which helps to improve the limb salvage rate of ischemic limbs and is a safe and effective method for treating diabetic foot.
In conclusion, the treatment of diabetic foot requires concerted efforts in many aspects, neither neglecting basic treatments such as controlling blood glucose, lipids, blood pressure and smoking cessation, nor focusing only on interventional or surgical treatments. With the continuous advancement of technology, the treatment of diabetic lower extremity arteriopathy is becoming a hot spot for clinicians to focus on, and multicenter, randomized, and large sample clinical studies will likely better interpret its clinical treatment effects.