Acute and chronic lower limb ischaemia

Limb ischaemia is a common clinical condition that causes considerable morbidity and mortality and represents a major drain on healthcare resources. Peripheral arterial disease (PAD) is the leading cause of both acute and chronic limb ischaemia. Chronic limb ischaemia may also be caused by non-atherosclerotic processes such as arterial entrapment, fibrosis or arteritis. Acute limb ischaemia may be also due to embolism, thrombosis or trauma. Duplex ultrasonography, computed tomography angiography and magnetic resonance angiography are now conventional forms of arterial imaging, with catheter angiography reserved for intervention. Risk factor modification is extremely important for all these patients, since many will also have significant coronary or cerebrovascular disease. Those with claudication often improve with structured exercise and if symptoms progress they may benefit from angioplasty or stenting. Arterial bypass remains the mainstay of treatment for patients with critical limb ischaemia if they are fit enough for surgery. Acute limb ischaemia is a surgical emergency and can be treated with surgical embolectomy or catheter-directed thrombolysis (depending on local expertise). Patients with irreversible limb ischaemia should be treated with primary amputation or palliation as appropriate.     

Incidental discovery of a long standing arteriovenous fistula after thrombectomy for acute lower limb ischaemia

INTRODUCTION

Arteriovenous fistula (AVF) is the abnormal connection between an artery and vein. Congenital AVF of the popliteal artery is very rare.

PRESENTATION OF CASE

89 year old lady presented with right acute lower limb ischaemia. She had unilateral chronic venous hypertensive change in the right leg. Femoral embolectomy was performed. Backflow was achieved. Arteriotomy was closed. The patient''s leg continued to deteriorate. She returned to theatre. On-table angiogram showed an occluded SFA. Thrombectomy was completed. SFA was patent but no blood flowed into the distal popliteal artery. A second on table angiogram revealed AVF between popliteal artery and vein. Dissection to the posterior aspect of the knee revealed the fistula. The vein was arterialized and enlarged. The AVF was ligated. Normal distal blood flow was achieved. Retrospectively we measured the leg lengths. Right leg was 3 cm longer than the left. The right leg circumference was 7 cm greater than the left. She reported chronic venous change from a young age. She did not report any history of trauma to the limb.

DISCUSSION

Popliteal artery to popliteal vein fistula is a rare. Trauma is the most common cause of popliteal AVF. Should the condition develop before closure of the epiphyses, there may be an increase in leg measurements.

CONCLUSION

We postulate that this case of AV fistula may be congenital due to discrepancy in leg measurements and unilateral chronic venous hypertensive change. Rarely persistent remnants of the embryonic sciatic artery can lead to arteriovenous anastomoses, which may be a possible aetiology.     

Acute and chronic limb ischaemia

Acute (ALI) and chronic limb ischaemic (CLI) make up a major part of the workload of vascular surgeons and carry considerable morbidity and mortality. Peripheral artery disease (PAD) is the major cause of these conditions. Diagnosis of these conditions involves proper use of imaging including duplex ultrasound, computed tomography angiography (CTA), magnetic resonance angiography (MRA), as well as invasive techniques like digital subtraction angiography (DSA). Management ranges from conservative techniques, the mainstay of management in intermittent claudication (IC), with medical optimization, through to endovascular and open revascularization techniques in CLI and ALI. Finally where no revascularization options exist, primary amputation or palliation must be considered.     

急性下肢缺血动脉再通后并发骨筋膜室综合征的诊治

目的：探讨急性下肢缺血动脉再通后并发骨筋膜室综合征的临床表现、早期诊治及预后。方法：回顾性分析2005年1月至2009年1月因急性下肢缺血在我科行动脉再通治疗后并发急性下肢骨筋膜室综合征病人的临床资料,包括发病原因、时间、治疗方式、治疗效果、骨筋膜室综合征的处理方法及预后。结果：126例病人因急性下肢缺血行动脉再通治疗,发病至再通时间平均为26h（3h至6d）,其中24例（共27条肢体）并发骨筋膜室综合征而行筋膜切开（包括3例行双侧肢体预防性切开）。21例动脉再通术后延迟切开时间平均为10（5—48）h,其中2例术中行血液透析,1例行术后血液透析。本组3例截肢,2例死亡（包括1例截肢）。结论：骨筋膜室综合征是急性下肢缺血动脉再通后的严重并发症,动脉再通后持续疼痛或疼痛加重伴局部张力升高者应高度怀疑为骨筋膜室综合征,其治疗方法是充分切开4个筋膜腔减压,同时动态监测病人电解质和肾功能指标,维持肾功能和内环境的稳定,必要时应早期进行透析。     

Acute and chronic limb ischaemia

Chronic limb ischaemia presents over time. The most common cause of chronic ischaemia is peripheral arterial disease (PAD). Risk factors for the development of PAD may be modifiable or non-modifiable (age, gender, ethnicity and family history). Intermittent claudication, the most common presenting symptom, may have a relatively benign prognosis in many cases, whereas critical limb ischaemia (CLI) refers to disease progression with threatened limb loss, and requires intervention. In contrast, acute limb ischaemia occurs suddenly, commonly due to thrombosis, embolization or trauma (including iatrogenic causes), and may also be limb threatening, requiring urgent investigation and intervention in order to reduce risks of limb loss.     

VAC therapy to promote wound healing after surgical revascularisation for critical lower limb ischaemia

Vacuum‐assisted closure (VAC) therapy is a new emerging non‐invasive system in wound care, which speeds up wound healing by causing vacuum, improving tissue perfusion and suctioning the exudates, and facilitating the removal of bacteria from the wound. The application of sub‐atmospheric pressure on the lesions seems to alter the cytoskeleton of the cells on the wound bed, triggering a cascade of intracellular signals that increase the rate of cell division and subsequent formation of granulation tissue. The aim of this study is to analyse the results of VAC therapy used as an adjuvant therapy for the treatment of foot wounds in patients affected by critical limb ischaemia (CLI) (Rutherford 6 class) after distal surgical revascularisation, to promote and accelerate the healing of ulcers. Twenty‐nine patients (20 males, 9 females; mean age 68·4) affected by CLI of Rutherford 6 class, after surgical revascularisation of the lower limb, underwent VAC therapy in order to speed up wound healing. Complete wound healing was achieved in 19 patients (65·51%), in an average period of 45·4 ± 25·6 days. VAC therapy is a valid aid, after surgical revascularisation, to achieve rapid healing of foot lesions in patients with CLI.     

Effect of hydrogen sulphide on inflammatory factors of the mitochondria after limb ischaemia‐reperfusion injury in rats

The goal of this study was to evaluate the effect of hydrogen sulphide on inflammatory factors and the energy metabolism of mitochondria after limb reperfusion injury in rats. Sixty Wistar rats were divided into three groups: the sham operated group, the control group (the ischaemia‐reperfusion injury [IRI] + normal saline group), and the experimental group (the IRI + H₂S group). An experimental rat model of limb IRI was established. Skeletal muscle samples were collected to observe the content of necrotic products (including myoglobin (MB), lysophosphatidylcholine (LPC), and lipid peroxidation (LPO)); blood samples were collected to observe changes in the contents of interleukin‐1 (IL‐1), Interleukin‐6 (IL‐6), and tumor necrosis factor‐α (TNF‐α); and the mitochondria of skeletal muscle cells were extracted for mitochondrial transmembrane potential measurement and adenosine triphosphate (ATP) content determination. The results underwent further statistical analysis. The contents of MB, LPC, and LPO in the limb skeletal muscle, liver, lung, and kidney tissues of rats in the control group were significantly increased (P < 0.05) after IRI, which was markedly attenuated by treatment with hydrogen sulphide (P < 0.05). Ischaemia/reperfusion of the lower extremities in rats triggered a significant increase in serum levels of IL‐1, IL‐6, and TNF‐α, which was significantly inhibited by treatment with H₂S during ischaemia/reperfusion. In addition, the inhibitory effect tended to be time‐dependent. After limb ischaemia/reperfusion, the mitochondrial transmembrane potential of skeletal muscle cells in the control group decreased significantly (P < 0.05), while the potential energy of the mitochondrial membrane in the experimental group was significantly higher than that in the control group (P < 0.05). The content of ATP in mitochondria of skeletal muscle cells of ischaemia‐reperfusion rats in the control group was significantly lower than that in the sham operated group (P < 0.05), while the content of ATP of mitochondria in the experimental group after H₂S treatment was significantly higher than the control group (P < 0.05). Hydrogen sulphide can alleviate the injury of skeletal muscle and distal organs after limb ischaemia‐reperfusion and reduce local inflammatory reaction, which is essential in alleviating mitochondrial transmembrane potential and energy metabolism disorder during reperfusion injury. The purpose of the study is to summarise the available information and provide theoretical support for the application of hydrogen sulphide in the treatment of limb IRI in skeletal muscle and distal organs.     

Acute limb ischaemia

Acute limb and/or digital ischaemia (ALI, Acute Limb Ischaemia) is a global healthcare problem that is associated with high morbidity and mortality. It is caused by occlusion of a native artery, vascular bypass graft, or angioplasty-site/stent due to embolization or thrombosis, or occlusion of digital micro-vessels due to vasospasm or thrombosis. The culprit risk factor for embolic ALI is most often cardiogenic associated with atrial fibrillation. Other risk factors for ALI include smoking, hypertension, raised cholesterol and diabetes. ALI is diagnosed clinically by identifying the classical “6 P's”: Pain, Pallor, Pulselessness, Perishing cold, Paraesthesia, and Powerlessness. Rutherford's classification is used to grade the severity of ALI, and helps the clinician ascertain whether the limb is viable (I), marginally threatened (IIa), immediately threatened (IIb), or non-salvageable (III). Immediate management of ALI involves analgesia, supplemental oxygen, intravenous fluids, intravenous heparin, and arranging for an urgent CT angiogram. Definitive revascularization options include open surgery, endovascular procedures, or a combined ‘hybrid’ surgical and radiological approach. If a limb, or digit, is non-salvageable primary amputation may be indicated. Dependent upon the severity of ischaemia and on patient fitness, the most appropriate management strategy may instead be conservative, including palliation. Whatever the management approach decided upon, the patient (and ideally their family and/or carers) should be appropriately counselled and given a realistic picture of their options, including doing nothing, with their associated risks and benefits.     

Heart energy metabolism after intestinal ischaemia and reperfusion

Background/purpose

Multiple organ failure subsequent to intestinal ischaemia and reperfusion (I/R) includes cardiac failure, but little is known about heart energy metabolism in this setting. This study investigates the effects of intestinal I/R on heart energy metabolism and evaluates the effects of moderate hypothermia.

Methods

Adult rats underwent intestinal ischaemia for 60 minutes followed by 120 minutes of reperfusion. Animals were maintained at either normothermia (36° to 38°C) or moderate hypothermia (30° to 32°C). In experiment A, 2 groups were studied: (1) sham at normothermia; (2) I/R at normothermia. After death, the heart was removed. Cardiac phosphoenergetics were assessed by ³¹P magnetic resonance spectroscopy; data are expressed as micromoles per gram. In experiment B, 4 groups were studied: (1) sham at normothermia, (2) I/R at normothermia, (3) sham at hypothermia, (4) I/R at hypothermia. At the end of the experiment, the heart was harvested. The activity of carnitine palmitoyl transferase I (CPT I), an important enzyme in the control of fatty acid oxidation, was measured; data are expressed as nanomoles per minute per unit citrate synthase. Results are expressed as mean ± SEM.

Results

In experiment A, there were no differences between the 2 study groups in cardiac phosphocreatine, inorganic phosphate, adenosine triphosphate (ATP), or in the ratio of inorganic phosphate to ATP. In experiment B, CPT I activity was decreased significantly after I/R at normothermia compared with normothermic sham, but this enzyme inhibition was prevented by hypothermia (3.9 ± 0.2; v I/R).

Conclusions

These results suggest that although cardiac ATP supply was maintained during intestinal I/R at normothermia, the balance of substrate utilisation was shifted from fatty acid oxidation to carbohydrate utilisation. However, moderate hypothermia modified these changes. The beneficial effect of moderate hypothermia on cardiac metabolism during intestinal I/R has potential clinical application in various surgical conditions.     

Acute and chronic ischaemia of the lower limb

Limb ischaemia is an important clinical problem due to the high prevalence of peripheral arterial disease (PAD) in the UK. The main risk factors are smoking and diabetes mellitus. In young patients, alternative diagnoses of embolus, thrombosis, arteritis, congenital anomaly, fibrosis and traumatic (including iatrogenic) arterial injury must be considered. Intermittent claudication, critical ischaemia and acute ischaemia are clinical diagnoses easily confirmed by ankle–brachial pressure index (ABPI) measurement. Non-invasive arterial assessment by duplex, magnetic resonance angiography and computed tomographic angiography are used to confirm the diagnosis and to plan intervention. Angiography is usually reserved for therapeutic intervention. Best medical therapy for PAD includes smoking cessation, aspirin, blood pressure control (angiotensin-converting enzyme inhibitors) and statin therapy. These interventions are proven to reduce heart attack and stroke. For claudicants, structured exercise classes improve maximum and pain-free walking distance; in addition, percutaneous angioplasty may be considered if they have a suitable lesion in the iliac, femoral or popliteal arteries. Patients with critical limb ischaemia require intervention to avoid limb loss; arterial reconstruction (angioplasty or bypass) is preferable to primary amputation, as preservation of mobility is an important determinant of quality of life. The acutely ‘threatened’ limb is a surgical emergency and requires immediate intervention, best performed in a specialized vascular unit.     

Recognising anaemia and malnutrition in vascular patients with critical limb ischaemia

INTRODUCTION

Anaemia is a common problem in surgical patients. Patients with critical limb ischaemia (CLI) suffer chronic inflammation, repeated infection, require intervention, and can have a protracted hospital stay. The aims of this study were to assess anaemia and nutritional status in patients presenting with CLI.

PATIENTS AND METHODS

Two observational studies were undertaken, initially a retrospective series of 27 patients with CLI. Patient demographics, clinical details, transfusion status and in-patient laboratory haemoglobin values (Hb) were recorded. In a prospective series of 32 patients, laboratory markers to identify the cause for anaemia were assessed. Further nutritional status was assessed by records of height, weight, body mass index and a validated scoring system.

RESULTS

In the retrospective series, 15 patients (56%) were anaemic. Ten (37%) were transfused a median of 2 units (range, 2–13), a total of 35 units. Patients who were transfused had lower Hb on admission (P = 0.0019), most were anaemic on admission (90%). At discharge, most patients were anaemic (n = 23; 83%). In the prospective series of 32 patients, 20 (63%) were anaemic. Nutritional assessment was performed on 18, only seven patients were scored undernourished. This was increased to 23 by an independent assessor. Anaemia was associated with malnutrition (n = 17; P = 0.049) and an increased hospital stay (mean 25 days [SD 16] vs mean 12 days [SD 8], P = 0.0125; total 513 vs 144 bed days).

CONCLUSIONS

Anaemia and poor nutrition are common and not recognised in vascular patients presenting with critical limb ischaemia. Anaemia is associated with and increased length of hospital stay.     

Protective effects of Urtica dioica L. on experimental testicular ischaemia reperfusion injury in rats

In this study, it was aimed to examine the effects of Urtica dioica L. (UD) that has antioxidant feature in the experimental testicular I/R model in rats in terms of anti‐apoptotic and antioxidative effects. In our study, 24 male rats were divided into three groups: control group, I/R group and I/R + UD (2 mg kg^?1) group. Seminiferous tubule calibre measurement, Johnson score, haematoxylin–eosin staining, proliferative cell nucleus antigen (PCNA) immunohistochemical staining and TUNEL as histopathological have been conducted. The structural deterioration in the testicular on I/R group has reduced after the treatment of UD. Our data indicate a significant reduction in the activity of in situ identification of apoptosis using terminal dUTP nick end labelling (TUNEL), and there was a rise in the expression of proliferating cell nuclear antigen (PCNA) in testis tissues of UD‐treated rats in the I/R group. The I/R + UD group showed a decrease in malondialdehyde levels and an increase in the activities of superoxide dismutase, catalase and glutathione peroxidase in comparison with the I/R group. It could be concluded that protective effects of UD on the I/R testicles are via reduction of histological damage, apoptosis, oxidative stress and lipid peroxidation.     

Spinal cord stimulation to achieve wound healing in a primary lower limb critical ischaemia referral centre

Critical lower limb ischaemia is a diffuse pathology that could cause claudication, severe ischaemic pain and tissue loss. The common treatment includes modification of risk factors, pharmacological therapy and endovascular or surgical revascularisation of the lower limb to restore a pulsatile flow distally. Spinal cord stimulator is seen as a valid alternative in patients unsuitable for revascularisation after endovascular or surgical revascularisation failure and as adjuvant therapy in the presence of a functioning bypass in patients with extensive tissue loss and gangrene presenting a slow and difficult wound healing. We report our experience on spinal cord stimulation (SCS) indication and implantation in patients with critical lower limb ischaemia, at a high‐volume centre for the treatment of peripheral arterial disease.     

Protective effect of edaravone,a free‐radical scavenger,on ischaemia‐reperfusion injury in the rat testis

OBJECTIVE

To investigate the effect of edaravone, a radical scavenger, on ischaemia‐reperfusion (I‐R) injury in the testes.

MATERIALS AND METHODS

Eight‐week‐old male Sprague‐Dawley rats were allocated to one of four groups: a no‐drug group subjected to induction of 30‐min of ischaemia and 60‐min reperfusion; two drug groups administered edaravone at 1 or 10 mg/kg intraperitoneal and then subjected to 30‐min ischaemia and 60‐min reperfusion; and a sham‐operated control group administered edaravone at 10 mg/kg intraperitoneal. To induce testicular I‐R, the right testis was exposed outside of the body and the testicular artery was clamped with a small clip for 30 min. Blood flow and nitric oxide (NO) release were monitored in real time simultaneously with a laser Doppler flowmeter and an NO‐selective electrode, respectively. After death the tissue levels of NO₂‐NO₃ (a marker of NO production), malondialdehyde (a marker of lipid peroxidation), 8‐hydroxydeoxyguanosine (a marker of oxidative DNA damage), myeloperoxidase (a marker of neutrophil infiltration), and heat‐shock protein 70 (HSP 70) and its mRNA were measured. The testicular tissue was also analysed histologically.

RESULTS

Clamping the testicular artery resulted in a decrease of blood flow to 0–5% of the basal level measured before clamping. NO release was increased during clamping and gradually recovered to the basal level on removing the clip. Interestingly, the peak of NO release in rats of the no‐drug group occurred at the start of reperfusion, while that in the high‐dose drug group occurred several minutes later. The levels of NO₂‐NO₃, malondialdehyde, 8‐hydroxydeoxyguanosine, myeloperoxidase and HSP 70 and its mRNA, and histological variables, were significantly greater in the no‐drug I‐R group than in the control, and these variables were ameliorated by treatment with edaravone.

CONCLUSION

These results indicate that edaravone reduces the oxidative stress and prevents the testicular damage induced by I‐R.