Diabetes Care for Patients with Peripheral Arterial Disease

Specificities of primary and secondary prevention of lower extremity artery disease: introduction to a series of reviews

This article briefly discusses the risk factors for the development of lower extremity artery disease, namely smoking, diabetes mellitus, hyperlipidemia/dyslipidemia and hypertension. Each of these risk factors will be discussed in detail in forthcoming articles of the journal.

Specificities of primary and secondary prevention of lower extremity artery disease in patients with diabetes mellitus

Diabetes mellitus (DM) is a major risk factor for lower extremity arterial disease (LEAD) and about 20% of symptomatic patients with LEAD have DM. In subjects with DM, LEAD is a cause of morbidity and mortality. DM typically causes complications in the form of macro- and microangiopathy. In these patients, macroangiopathy manifests as atherosclerosis like in non-diabetic patients. However, its course is accelerated due to accompanying risk factors like hyperlipidemia and hypertension, with cumulative effects. Other factors are also relevant such as inflammation, endothelial dysfunction, platelet activation, blood rheological properties, hypercoagulability, and factors stimulating vascular smooth muscle cell proliferation. Additionally, DM is a risk factor for restenosis and amputation. DM is strongly associated with femoral-popliteal and tibial LEAD, which manifests earlier in patients with DM and may progress more rapidly to critical limb ischemia. Diabetic microangiopathy is characterized by arteriolosclerosis and interstitial fibrosis which additionally affects progression and outcomes of angiopathy of lower limbs. Glycemic control particularly decreases microangiopathic complications, while prevention of macrovascular complications requires treatment of accompanying risk factors like hypertension and dyslipidemia.

Health impacts of seated arm ergometry training in patients with a diabetic foot ulcer: protocol for a randomised controlled trial

INTRODUCTION

Once diagnosed with a diabetic foot ulcer (DFU), patients are advised to offload, keeping pressure off the foot in order to facilitate ulcer healing. An increase in offloading is often accompanied by reductions in physical activity which can worsen the overall health of patients.While unable to perform traditional forms of upright activity, one mode of exercise that would allow patients to be physically active while adhering to offloading instruction is seated arm ergometry. The merits of tailored aerobic exercise in DFU remain unexplored.

METHODS AND ANALYSIS

This is a prospective open-label randomised controlled trial. Participants will be randomised to one of two groups, an exercise intervention group or control. The intervention group are required to undertake arm ergometry training at a moderate intensity (65%-75% HRpeak), three times per week for 12 weeks as individually prescribed by an exercise physiologist, while the control group will continue to receive standard care alone. Assessment of outcome measures will occur at baseline and after the intervention period, these will include: a seated VO₂ peak test, a blood sample, a short physical performance battery, a dual-energy X-ray absorptiometry scan and completing a range of health-based questionnaires. The above will be used to determine: cardiorespiratory fitness, metabolic health, physical function, body composition and quality of life, respectively. Ulcer area will also be measured as an approximate marker of ulcer healing.

ETHICS AND DISSEMINATION

This trial has been approved by 'Yorkshire & The Humber-Leeds West Research Ethics Committee' (19/YH/0269). Trial results will be published in peer-reviewed journals and through conference presentations.

TRIAL REGISTRATION NUMBER

ISRCTN16000053. Registered in accordance with WHO Trial Registration Data Set (version 1.3.1).

Short vs prolonged dual antiplatelet treatment upon endovascular stenting of peripheral arteries

INTRODUCTION

Peripheral artery disease (PAD) is a highly prevalent disorder with a substantial economical burden. Dual antiplatelet treatment (DAPT) upon endovascular stenting to prevent acute thrombotic reocclusions is an universally accepted practice for postinterventional management of PAD patients. However, the optimal period of time for DAPT upon endovascular stenting is not known.

METHODS

In the current nonrandomized, retrospective monocentric study, we evaluated the duration of DAPT upon endovascular stenting. A total of 261 endovascular SFA and iliac stenting procedures were performed on 214 patients and these patients were subdivided into a short (4-6 weeks) or a prolonged (8-12 weeks) DAPT regime group. More than 65% of the patients included were male, approximately 35% were diabetic, and 61% had a history of smoking. Of all the patients, 90% exhibited a Rutherford stage 2-3, and approximately half of the patients had a moderate-to-severe calcified target lesion with a length of >13 cm. Major safety end points were defined as any bleeding, compartment syndrome, and ischemic events. In addition to this, patency, all-cause mortality, as well as amputation were followed up over a period of 12 months upon intervention.

RESULTS

Twelve months after endovascular stenting, primary patency in our cohort was comparable between the groups (83.94% short vs 79.8% long DAPT, P>0.05). Major bleeding occurred in 18 cases without any difference between the groups (P>0.05). In addition, during the 12-month follow-up, 6 (3.4%) patients in the short and 3 (3.5%) in the prolonged DAPT regime suffered a stroke/transient ischemic attack (P>0.05). In addition, there was no difference regarding mortality and amputation rate comparing short vs prolonged DAPT regime in a 12-month follow-up.

CONCLUSION

In the current cohort, prolonged DAPT after endovascular stenting had no beneficial effect on the outcome in a 12-month follow-up.

Diagnosis and assessment of peripheral arterial disease in the diabetic foot

Approximately half of all patients with a diabetic foot ulcer have co-existing peripheral arterial disease. Identifying peripheral arterial disease among patients with foot ulceration is important, given its association with failure to heal, amputation, cardiovascular events and increased risk of premature mortality. Infection, oedema and neuropathy, often present with ulceration, may adversely affect the performance of diagnostic tests that are reliable in patients without diabetes. Early recognition and expert assessment of peripheral arterial disease allows measures to be taken to reduce the risk of amputation and cardiovascular events, while determining the need for revascularization to promote ulcer healing. When peripheral arterial disease is diagnosed, the extent of perfusion deficit should be measured. Patients with a severe perfusion deficit, likely to affect ulcer healing, will require further imaging to define the anatomy of disease and indicate whether a revascularization procedure is appropriate.

What can I do with a patient with diabetes and critically impaired limb perfusion who cannot be revascularized?

A patient with limb-threatening diabetic foot syndrome in whom relevant peripheral arterial occlusive disease is proven should receive arterial revascularization as soon as possible to avoid major amputation. However, 3 conditions may make it impossible to effectively restore limb perfusion: the patient will not profit from arterial revascularization owing to excessive tissue loss or sepsis ("too late"), the patient cannot be revascularized due to severe comorbidities ("too sick"), and arterial reconstruction is impossible because of technical and anatomical shortcomings in a patient who is otherwise fit for operation ("nonreconstructible limb perfusion"). This review outlines the therapeutic options specifically in the third group of patients in whom no technical option for surgical or endovascular revascularization exists.

Foot examinations of diabetes patients by primary health care nurses in Auckland, New Zealand

AIMS

To identify factors associated with patients receiving foot examinations by primary health care nurses.

METHODS

A cross-sectional survey of 287 randomly sampled primary health care nurses, from a total of 1091 in Auckland, completed a postal self-administered questionnaire and telephone interview. Biographical and diabetes management details were collected for 265 diabetes patients consulted by the nurses on a randomly selected day.

RESULTS

A response rate of 86% was achieved. Nurses examined patient's feet in 46% of consultations. Controlling for demographic variables, foot examinations were associated with age, odds ratio (1.25, 95% CI 0.57-2.74) for patients aged 51-65 years and >66 years (2.50, 1.08-5.75) compared with those ≤50 years, consultations by district compared with practice nurses (14.23, 95% CI 3.82-53.05), special programme consultations compared with usual follow-up consults (8.81, 95% CI 2.99-25.93) and length of consultation (1.89, 0.72-4.97) for 15-30 min and (4.45, 95% CI 1.48-13.41) >30 min compared with consultations ≤15 min, or for wound care (2.58, 1.01-6.61).

CONCLUSIONS

Diabetes foot examinations by primary health care nurses varies greatly, and are associated with characteristics of the patient (age, need for wound care) and the consultation (district nurses, diabetes programme and duration).

Role of TRPM7 channels in hyperglycemia-mediated injury of vascular endothelial cells

This study investigated the change of transient receptor potential melastatin 7 (TRPM7) expression by high glucose and its role in hyperglycemia induced injury of vascular endothelial cells. Human umbilical vein endothelial cells (HUVECs) were incubated in the presence or absence of high concentrations of D-glucose (HG) for 72h. RT-PCR, Real-time PCR, Western blotting, Immunofluorescence staining and whole-cell patch-clamp recordings showed that TRPM7 mRNA, TRPM7 protein expression and TRPM7-like currents were increased in HUVECs following exposure to HG. In contrast to D-glucose, exposure of HUVECs to high concentrations of L-glucose had no effect. HG increased reactive oxygen species (ROS) generation, cytotoxicity and decreased endothelial nitric oxide synthase protein expression, which could be attenuated by knockdown of TRPM7 with TRPM7 siRNA. The protective effect of silencing TRPM7 against HG induced endothelial injury was abolished by U0126, an inhibitor of the extracellular signal-regulated kinase signaling pathway. These observations suggest that TRPM7 channels play an important role in hyperglycemia-induced injury of vascular endothelial cells.

Cilostazol prevents foot ulcers in diabetic patients with peripheral vascular disease

Diabetic patients are at high risk of foot ulcerations that may lead to limb amputations with important socio-economic impact. Peripheral vascular disease may be frequently associated in diabetes mellitus type II with its main symptom, intermittent claudication. Many studies reported the known efficacy of cilostazol in treating vascular claudication. Metalloproteinase-9 (MMP-9) seems to be a biochemical marker implicated in chronic wounds and in particular in diabetic foot ulcers. Cilostazol appears to have a lowering effect on MMP-9 levels and this may suggest a beneficial effect in order to prevent or retard the onset of foot ulcer in diabetic patients. In our study, two groups of diabetic patients with peripheral vascular disease were divided into two groups according to the presence of claudication in order to receive cilostazol. Group A (31 patients without claudication) were not eligible to receive cilostazol whereas Group B (47 patients with claudication) received cilostazol administration for 24 weeks (100 mg orally twice daily). Median follow up was of 16 months. During the follow up, 4·25% of patients of Group B and 35·48% of patients of Group A (P < 0·01) showed onset of foot ulceration. Although further randomised and controlled studies are required cilostazol seems to show beneficial effects for primary prevention of diabetic foot ulcers.

Evidence-based management of PAD & the diabetic foot

Diabetic foot ulceration (DFU) is associated with high morbidity and mortality, and represents the leading cause of hospitalization in patients with diabetes. Peripheral arterial disease (PAD), present in half of patients with DFU, is an independent predictor of limb loss and can be difficult to diagnose in a diabetic population. This review focuses on the evidence for therapeutic strategies in the management of patients with DFU. We highlight the importance of timely referral of patients presenting with a new foot ulcer to a multidisciplinary team, which includes vascular surgeons and interventional radiologists.

Diagnostics and treatment of the diabetic foot

Every 30 s, a lower limb is amputated due to diabetes. Of all amputations in diabetic patients 85% are preceded by a foot ulcer which subsequently deteriorates to a severe infection or gangrene. There is a complexity of factors related to healing of foot ulcers including strategies for treatment of decreased perfusion, oedema, pain, infection, metabolic disturbances, malnutrition, non-weight bearing, wound treatment, foot surgery, and management of intercurrent disease. Patients with diabetic foot ulcer and decreased perfusion do often not have rest pain or claudication and as a consequence non-invasive vascular testing is recommended for early recognition of ulcers in need of revascularisation to achieve healing. A diabetic foot infection is a potentially limb-threatening condition. Infection is diagnosed by the presence or increased rate of signs inflammation. Often these signs are less marked than expected. Imaging studies can diagnose or better define deep, soft tissue purulent collections and are frequently needed to detect pathological findings in bone. The initial antimicrobial treatment as well as duration of treatment is empiric. There is a substantial delay in wound healing in diabetic foot ulcer which has been related to various abnormalities. Several new treatments related to these abnormalities have been explored in wound healing with various successes. An essential part of the strategy to achieve healing is an effective offloading. Many interventions with advanced wound management have failed due to not recognizing the need for effective offloading. A multidisciplinary approach to wounds and foot ulcer has been successfully implemented in different centres with a substantial decrease in amputation rate.

Chapter V: Diabetic foot

Ulcerated diabetic foot is a complex problem. Ischaemia, neuropathy and infection are the three pathological components that lead to diabetic foot complications, and they frequently occur together as an aetiologic triad. Neuropathy and ischaemia are the initiating factors, most often together as neuroischaemia, whereas infection is mostly a consequence. The role of peripheral arterial disease in diabetic foot has long been underestimated as typical ischaemic symptoms are less frequent in diabetics with ischaemia than in non-diabetics. Furthermore, the healing of a neuroischaemic ulcer is hampered by microvascular dysfunction. Therefore, the threshold for revascularising neuroischaemic ulcers should be lower than that for purely ischaemic ulcers. Previous guidelines have largely ignored these specific demands related to ulcerated neuroischaemic diabetic feet. Any diabetic foot ulcer should always be considered to have vascular impairment unless otherwise proven. Early referral, non-invasive vascular testing, imaging and intervention are crucial to improve diabetic foot ulcer healing and to prevent amputation. Timing is essential, as the window of opportunity to heal the ulcer and save the leg is easily missed. This chapter underlines the paucity of data on the best way to diagnose and treat these diabetic patients. Most of the studies dealing with neuroischaemic diabetic feet are not comparable in terms of patient populations, interventions or outcome. Therefore, there is an urgent need for a paradigm shift in diabetic foot care; that is, a new approach and classification of diabetics with vascular impairment in regard to clinical practice and research. A multidisciplinary approach needs to implemented systematically with a vascular surgeon as an integrated member. New strategies must be developed and implemented for diabetic foot patients with vascular impairment, to improve healing, to speed up healing rate and to avoid amputation, irrespective of the intervention technology chosen. Focused studies on the value of predictive tests, new treatment modalities as well as selective and targeted strategies are needed. As specific data on ulcerated neuroischaemic diabetic feet are scarce, recommendations are often of low grade.

Peripheral arterial disease in diabetic patients with renal insufficiency: a review

Peripheral arterial disease is common among diabetic patients with renal insufficiency, and most of the diabetic patients with end-stage renal disease (ESRD) have peripheral arterial disease. Ischaemia is probably overrepresented as an etiological factor for a diabetic foot ulcer in this group of patients compared with other diabetic patients. ESRD is a strong risk factor for both ulceration and amputation in diabetic patients. It increases the risk of nonhealing of ulcers and major amputation with an OR of 2.5-3. Renal disease is a more important predictor of poor outcome after revascularizations than commonly expected. Preoperative vascular imaging is also affected by a number of limitations, mostly related to side effects of contrast agents poorly eliminated because of kidney dysfunction. Patients with renal failure have high perioperative morbidity and mortality. Persistent ischaemia, extensive infection, forefoot and heel gangrene, poor run-off, poor cardiac function, and the length of dialysis-dependent renal failure all affect the outcome adversely. Despite dismal overall outcome, recent data indicate that by proper selection, favourable results can be obtained even in ESRD patients, with the majority of studies reporting 1-year limb salvage rates of 65-75% after revascularization among survivors. High 1-year mortality of 38% reported in a recent review has to be taken into consideration, though. The preferential use of endovascular-first approach is attractive in this vulnerable multimorbid group of patients, but the evidence for endovascular treatment is very scarce. The need for complete revascularization of the foot may be even more important than in other patients with ischaemic ulcerated diabetic foot because there are a number of factors counteracting healing in these patients. Typically, half of the patients are reported to lose their legs despite open bypass. To control tissue damage and improve chances of ulcer healing, one should understand that early referral to vascular consultation is necessary.

Strategies for antiplatelet targets and agents

Platelets play a key role in thrombosis and haemostasis, which can be either beneficial or deleterious depending on the circumstance. Antiplatelet therapy is the 'cornerstone' in the prevention and treatment of thrombotic diseases. Platelet activation is a complex process known as transmembrane signaling which then serves to activate the platelet via a cascade of biochemical interactions. Currently available strategies of antiplatelet therapy are generally based on the signaling pathway of platelet activation, which possess the characters that mono-agent, mono-target, and mainly irreversible inhibition. Therefore, both established and novel antiplatelet agents have their own pros and cons and such problems as resistance, drug-drug interaction, discontinuation and monitoring, etc. have been appeared. Due to the problems existing in current antiplatelet agents, future new strategies for antiplatelet targets, agent-developing and treatment might probably include three aspects: targeting the factors associated with platelet hyperactivity, developing novel antiplatelet agents with multiple targets, mild and reversible properties from natural products, and keeping healthy lifestyle and emphasizing prevention.