Lipid peroxidation as a cause of lower limb swelling following femoro-popliteal bypass grafting

Compression therapy in peripheral artery disease: a literature review

OBJECTIVE

Our objective is to examine the pathophysiology of oedema in the ischaemic and post-revascularised limb, compare compression stockings to pneumatic compression devices, and summarise compression regimens in patients with severe peripheral artery disease (PAD) without revascularisation, after revascularisation, and in mixed arterial and venous disease.

METHOD

A scoping literature review of the aforementioned topics was carried out using PubMed.

RESULTS

Compression therapy has been shown to increase blood flow and aid in wound healing through a variety of mechanisms. Several studies suggest that intermittent pneumatic compression (IPC) devices can be used to treat critical limb ischaemia in patients without surgical options. Additionally, compression stockings may have a role in preventing oedema after peripheral artery bypass surgery, thereby diminishing pain and reducing the risk of surgical wound dehiscence.

CONCLUSION

Oedema may occur in the ischaemic limb after revascularisation surgery, as well as in combination with venous disease. Clinicians should not fear using compression therapy in PAD.

The Use of Transcutaneous Electrical Stimulation of the Calf in Patients Undergoing Infrainguinal Bypass Surgery

BACKGROUND

Infrainguinal bypass surgery is frequently associated with postoperative reperfusion edema of the limb. The etiology is thought to be multifactorial, and there is as yet no standardized treatment protocol for this problem. The primary aim of this study was to assess whether the use of intermittent electrical stimulation of the calf muscles after infrainguinal bypass surgery was effective in reducing the incidence of edema, and the secondary aims to determine the effect of calf muscle stimulation on arterial and venous flow in the operated leg.

METHODS

Forty patients due to undergo infrainguinal bypass surgery for critical lower-limb ischemia (Fontaine grading III-IV or Rutherford grading II-III) were recruited prospectively and randomly divided into the control group, who received the current standard of care, and study group, who received electrical calf muscle stimulation for a 1 hour session twice daily for the first postoperative week. Preoperatively and postoperatively, the leg was measured at 3 predetermined points and a duplex ultrasound scan performed.

RESULTS

The groups were well matched for all parameters. At 1 week, the below knee and calf girth were less in the study group (P = 0.025 and P = 0.043, respectively). Venous flow volumes at rest and on stimulation were higher in the study group (P = 0.010 and P = 0.029, respectively). At 6 weeks, the below knee girth and amount of pitting edema were less in the study group (P = 0.011 and P = 0.014, respectively).

CONCLUSIONS

We conclude that transcutaneous electrical stimulation of the calf decreased lower-limb swelling at 1 and 6 weeks, and increased the venous flow volume at rest and on stimulation at 1 week in patients undergoing infrainguinal bypass surgery for critical ischemia regardless of patient factors or the type of bypass surgery performed or graft used.

Pathophysiology and treatment of edema following femoropopliteal bypass surgery

Substantial lower-limb edema affects the majority of patients who undergo peripheral bypass surgery. Edema has impairing effects on the microvascular and the macrovascular circulation, causes discomfort and might delay the rehabilitation process of the patient. However, the pathophysiology of this edema is not well understood. The Cochrane Library and Medline were used to retrieve literature on edema following peripheral bypass surgery. Factors other than local wound healing alone are suggested in the literature to play a role, given the severity and duration of this edema. Hyperemia, microvascular permeability, reperfusion-associated inflammation and lymphatic disruptions are likely to facilitate the development of edema. Preventive methods could be lymphatic-sparing surgery, intraoperative antioxidative therapy and postoperative elevation. Successful treatment strategies to reduce postoperative edema are based on lymph massage and external compression. In conclusion, the pathophysiology of edema following peripheral surgery is not fully understood, although reperfusion-associated inflammation and lymphatic disruptions are likely to play a crucial role. When future less-invasive techniques prove to be successful, postoperative edema might be minimized. Until then, a careful lymphatic-sparing dissection should be executed when performing a peripheral bypass reconstruction. Postoperatively, the use of compression stockings and leg elevation are currently the golden standards.

The effects of cilostazol on exercise-induced ischaemia-reperfusion injury in patients with peripheral arterial disease

OBJECTIVES

Cilostazol improves walking distance in peripheral arterial disease (PAD) patients. The study objectives were to assess the effects of cilostazol on walking distance, followed by the additional assessment of cilostazol on exercise-induced ischaemia-reperfusion injury in such patients.

METHODS

PAD patients were prospectively recruited to a double-blinded, placebo-controlled trial. Patients were randomised to receive either cilostazol 100mg or placebo twice a day. The primary end-point was an improvement in walking distance. Secondary end-points included the assessment of oxygen-derived free-radical generation, antioxidant consumption and other markers of the inflammatory cascade. Initial and absolute claudication distances (ICDs and ACDs, respectively) were measured on a treadmill. Inflammatory response was assessed before and 30 min post-exercise by measuring lipid hydroperoxide, ascorbate, alpha-tocopherol, beta-carotene, P-selectin, intracellular and vascular cell-adhesion molecules (I-CAM and V-CAM), thromboxane B(2) (TXB(2)), interleukin-6, interleukin-10, high-sensitive C-reactive protein (hsCRP), albumin-creatinine ratio (ACR) and urinary levels of p75TNF receptor. All tests were performed at baseline and 6 and 24 weeks.

RESULTS

One hundred and six PAD patients (of whom 73 were males) were recruited and successfully randomised from December 2004 to January 2006. Patients who received cilostazol demonstrated a more significant improvement in the mean percentage change from baseline in ACD (77.2% vs. 26.6% at 6 weeks, p=0.026 and 161.7% vs. 79.0% at 24 weeks, p=0.048) as compared to the placebo. Cilostazol reduced lipid hydroperoxide levels compared to a placebo-related increase before and after exercise (6 weeks: pre-exercise: -11.8% vs. +5.8%, p=0.003 and post-exercise: -12.3% vs. +13.9%, p=0.007 and 24 weeks: pre-exercise -15.5% vs. +12.0%, p=0.025 and post-exercise: -9.2% vs. +1.9%, p=0.028). beta-Carotene levels were significantly increased in the cilostazol group, compared to placebo, before exercise at 6 and 24 weeks (6 weeks: 34.5% vs. -7.4%, p=0.028; 24 weeks: 34.3% vs. 17.7%, p=0.048). Cilostazol also significantly reduced P-selectin, I-CAM and V-CAM levels at 24 weeks as compared to baseline (p<0.05). There was no difference between treatment groups for ascorbate, alpha-tocopherol, interleukin-6 and -10, hsCRP and p75TNF receptor levels.

CONCLUSIONS

Cilostazol significantly improves ACD, in addition to attenuating exercise-induced ischaemia-reperfusion injury, in PAD patients.

PON1 55/192 polymorphism, oxidative stress, type, prognosis and severity of stroke

We investigated the association of PON1 55/192 polymorphisms with type, severity and prognosis of stroke and oxidative markers. Paraoxonase1 (PON1), Glutathione Reductase (GSH-Rd) and Malondialdehyde (MDA) levels were measured at day 1 and at day 5 following the onset of stroke. Genotypes were determined by polymerase chain reaction and restriction digestion. The frequencies of QQ and MM genotypes of PON1 192 and PON1 55, respectively, were significantly higher in controls than in patients. However, the allele frequencies of PON1 192 R and PON1 55 L were significantly more frequent in patients compared to controls. The frequency of combined genotype of RR/LL was significantly higher in cardioembolic group than in atherothrombotic group. PON1 activities were significantly diminished in stroke patients compared to controls. In contrast, serum MDA levels were significantly greater in patients than the values in controls. GSH-Rd activity was higher in patients with small lesion and good prognosis than those with large and poor prognosis. Low density lipoprotein (LDL) levels in patients with large lesions were higher than those with small lesions. PON1 55/192 polymorphisms influence activity of the enzyme. PON1 55/192 genotypes have been associated with MDA levels. In conclusion, PON1 genetic variations are associated with risk factors, severity, type and prognosis of stroke and oxidative stress.

Epidural anesthesia may attenuate lipid peroxidation during aorto-femoral surgery

PURPOSE

To determine the effect of epidural anesthesia (EP) on oxygenation of the chronically ischemic limb in patients undergoing aorto-femoral bypass grafting and to assess whether it produces an alteration of lipid peroxidation and antioxidant status following revascularization.

METHODS

In this prospective, randomized, single-blinded study 40 ASA II or III patients undergoing elective aorto-femoral bypass grafting were allocated to receive general anesthesia (group GA, n = 20), or epidural + GA (group EP, n = 20) during surgery. Femoral venous blood-gas status, activities of the protecting antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidase (GSH-px), glutathione reductase (GSH-rd), glutathione (GSH) and thiobarbituric acid-reactive substances (TBARS) as a marker of lipid peroxidation were determined in blood samples taken from the femoral vein at different intervals before and after revascularization.

RESULTS

Before the induction of anesthesia in group EP, femoral venous PO(2) [mean (standard deviation), 95% confidence interval] increased after achieving an adequate level of blockade by EP extending to the dermatomal level of T6-8 [29.32 (4.6), 26.34-32.30 to 36.29 (4.6), 33.37-39.22 mmHg, P < 0.05]. Femoral venous PO(2) was similar in both groups thereafter. In the GA group a significant increase in erythrocyte TBARS was observed immediately after restoration of blood flow when compared with baseline values [221.32 (102), 148.35-294-29 to 337.26 (123) 248.99-425.53 nmol*g(-1) hemoglobin, P < 0.01] but not at any other moment. In the EP group TBARS did not increase throughout the study. Within group comparisons revealed no significant differences in GSH, GSH-px, GSH-rd and SOD.

CONCLUSION

In patients with atherosclerotic aorto-iliac occlusive disease EP may possibly attenuate lipid peroxidation following revascularization but has no effect on antioxidant enzyme activities.

Extraperitoneal Approach Reduces Neutrophil Activation, Systemic Inflammatory Response and Organ Dysfunctionin Aortic Aneurysm Surgery

OBJECTIVES

to compare the effects of transperitoneal and extraperitoneal approaches on systemic inflammatory response, neutrophil activation and organ dysfunction in elective abdominal aortic aneurysm (AAA) repair.

PATIENTS AND METHODS

twenty patients admitted for elective infrarenal AAA repair were prospectively randomised into transperitoneal (n =10) or extraperitoneal ( n =10) groups. Neutrophil activation was assessed by measuring the plasma levels of neutrophil elastase/alpha(1)-anti-trypsin complexes before surgery, intraoperatively and at 6 h, 12 h, 24 h and then daily after surgery. Venous blood samples for estimation of liver function tests, full blood counts, urea and electrolytes and arterial samples for blood gas analysis were taken daily from preoperatively to day 5 after surgery. Multiple organ dysfunction (MOD) and systemic inflammatory response (SIR) scores were calculated daily.

RESULTS

the concentrations of neutrophil elastase/alpha(1)-anti-trypsin complexes were significantly higher in the transperitoneal group at 6 h after surgery compared to the extraperitoneal group (799(455-921) ng/ml (median(i.q.r.)) vs 307(171-395) ng/ml, p<0.005), and at 12 h (397(364-936) ng/ml vs 319(134-352) ng/ml, p <0.05). The MOD scores were significantly higher in the transperitoneal group in comparison to the extraperitoneal group at day 1 (2.5(2-3.3) vs 1(0-1), p<0.001) and day 2 (2.5(2-3.3) vs 1(0-1), p <0.001). The SIR scores were also significantly higher at day 1 (1(0-2) vs 0, p <0.01), day 2 (1.5(0-2.3) vs 0, p <0.01), and day 3 (1(0-1) vs 0, p <0.05).

CONCLUSIONS

neutrophil activation, systemic inflammatory response and organ dysfunction are increased in elective AAA repair when a transperitoneal approach is used. This may be related to intestinal manipulation and mesenteric traction which are reduced in the extraperitoneal approach.

Lower limb oedema following distal arterial bypass grafting

Lower-limb oedema following arterial bypass surgery for ischemia is a common sequela which can complicate wound healing or delay resumption of mobility. Its exact pathogenesis remains uncertain but many theories have been proposed. Lymphatic disruption during arterial exposure, and endothelial damage from atrophy of the media and oxygen-derived free radical release are currently favoured hypotheses. Infrequently, deep vein thrombosis follows surgery and may exacerbate the condition. Efforts aimed at reducing the oedema, such as the use of lymphatic preserving incisional approaches or the use of antioxidants, have given conflicting results. The use of compression hosiery and leg elevation appear to be the most effective measures in reducing postoperative lower limb oedema.

Lower leg electrical impedance after distal bypass surgery

Electrical impedance was determined in 13 patients following distal bypass surgery to evaluate lower leg oedema as reflected by its circumference. Tissue injury was assessed by the plasma concentration of muscle enzymes. After surgery, the volume of the control lower leg increased from 1250 (816-2373) to 1384 (874-2345) ml (median and range; P < 0.05), where the impedance did not change significantly from 140 (92-181) ohms. The volume of the operated leg increased more [from 1129 (824-2373) to 1600 (1090-2837) ml], and the decrease in electrical impedance was also pronounced [137 (125-169) to 83 (69-104) ohms (P < 0.001)]. Tissue injury after surgery was indicated by an increase in total creatine kinase (n = 17) and MB isoenzyme of creatine kinase (n = 8) (P < 0.05). Myoglobin (n = 8) had increased already during surgery (P < 0.05), whereas there was no significant change in the plasma concentration of troponin I (n = 8). In conclusion, tissue injury was reflected by increases in muscle enzymes in plasma. We found an inverse correlation between lower leg electrical impedance and volume, but the deviation in electrical impedance was approximately twice that of the leg volume. Electrical impedance appears to be a useful method for the evaluation of lower leg oedema after distal bypass surgery.

The relationship between the delayed improvement in ankle-brachial pressure index and changes in limb volume following balloon angioplasty for leg ischaemia

OBJECTIVES

To investigate the association between changes in the ankle-brachial pressure index (ABPI) and simultaneous changes in calf volume following percutaneous transluminal angioplasty (PTA) for chronic leg ischaemia.

MATERIALS

A total of 37 consecutive patients undergoing PTA for chronic leg ischaemia.

METHODS

Bilateral calf volume, as calculated from girth measurements, and ABPI were determined before PTA, and repeated 24 h and 1 week following the procedure. Changes in the calf volume of the treated leg, both absolute and relative to changes of the non-treated leg, were then related to simultaneous changes in ABPI.

RESULTS

Twenty-four hours following PTA, the calf volumes of both legs were decreased, although the ratio of the treated: untreated leg had increased by 2.4% (CI + 1.1-3.7, p < 0.01). After 1 week there was no difference in calf volume. These patterns were observed both in the 21 patients who had ABPI improvement of 0.15 or more 1 week following PTA, and in the 16 whose ABPI was unchanged. In the former group ABPI improved by a further 0.13 between 24 h and 1 week following PTA (p < 0.05), but there was no relationship between this delayed ABPI increase and simultaneous changes in calf volume.

CONCLUSIONS

We did not detect any significant calf swelling following PTA. Furthermore, changes in ABPI were not related to changes in calf volume.

The generation of byproducts of lipid peroxidation following carotid endarterectomy

The aim of this study was to determine whether free radical-induced lipid peroxidation occurs following transient carotid clamping. Jugular vein plasma levels of malondialdehyde (MDA) and diene conjugates (DC) were estimated in 24 patients undergoing carotid endarterectomy, at the beginning of the operation (To), just prior to clamping the carotid artery before the shunt was removed for closure of the arteriotomy (Ts), and at 30 (T30), 60 (T60), 120 (T120), 180 (T180) and 300 (T300) seconds after the clamps were released. Carotid clamp times were recorded. Significant elevations in the concentrations of both MDA and DC were observed at T60 after clamp release (MDA = 559 +/- 64 pmol/ml, DC = 428 +/- 32 units/ml), in comparison to concentrations at To (MDA = 408 +/- 34 pmol/ml, p < 0.01; DC = 374 +/- 28 units/ml, p < 0.05), returning to baseline at T300. There was a significant correlation between the percentage rise in MDA concentration and the duration of clamp-induced ischaemia (r = 0.45, p = 0.03). The significance of this burst of MDA and DC is unclear especially as the one patient who sustained a postoperative neurological deficit displayed no rise in the concentration of either. If this rise is related to free radical generation following ischaemia-reperfusion injury it may play an important role in influencing the clinical outcome in the patients.

Does the limb swell after revascularisation by percutaneous transluminal angioplasty?

OBJECTIVE

To discover if limb swelling occurs after successful revascularisation by percutaneous transluminal angioplasty (PTA).

DESIGN

Prospective Study.

SETTING

Vascular Laboratory.

MATERIALS

Twenty-five patients with occlusive arterial disease of the lower limb revascularised by percutaneous transluminal angioplasty were studied.

CHIEF OUTCOME MEASURES

The ankle/brachial pressure index and foot volumes measured by water displacement plethysmography were measured before and after PTA.

MAIN RESULTS

The volume of the revascularised limb increased by 2% on the first day postangioplasty (p = 0.009) and 4% on the 7th day (p < 0.001) compared with the contralateral leg.

CONCLUSIONS

Leg swelling is a consequence of revascularisation of the ischaemic limb and occurs in the absence of damage to the lymphatic drainage of the limb.

Venous haemodynamics and the occurrence of leg oedema in patients with popliteal aneurysm

OBJECTIVES

To see whether popliteal aneurysms cause venous obstruction and to investigate leg oedema and DVT following repair.

DESIGN

Prospective open clinical study.

SETTING

University Department of Surgery.

MATERIALS

8 patients undergoing popliteal aneurysm repair in 9 legs (1 bilateral repair).

CHIEF OUTCOME MEASURES

CT and plethysmographic evidence of vein compression, the occurrence of postoperative leg oedema and phlebographic evidence of deep venous thrombosis (DVT).

MAIN RESULTS

Preoperative CT investigation showed that the aneurysm compressed the popliteal vein in 6/9 limbs where surgery was planned and in 9/10 limbs with popliteal aneurysms (patent or occluded) of > 2 cm diameter (p < 0.01). However, on the CT image, increased collateral network could be observed and most patients had normal venous drainage prior to operation as assessed by air plethysmography. Postoperatively, leg volume was measured by the formula of a truncated cone. Following vascular reconstruction, leg volume increased by 23%. Except for one patient with a confirmed DVT preoperatively, postoperative venous congestion and DVT was not observed in the operated leg as assessed by phlebography and plethysmography.

CONCLUSIONS

Popliteal artery aneurysms "2 cm diameter usually compress and dislocate the popliteal vein prior to operation. However, sufficient venous drainage is maintained, possibly because of an increased collateral venous network. Disruption of lymph channels with secondary lymphoedema is probably the most important mechanism behind the leg swelling observed in patients following popliteal aneurysm repair.

Ascorbate and malondialdehyde in stroke patients

It is believed that free radical formation and subsequent oxidative damage in the form of lipid peroxidation may be a factor in the cerebral damage secondary to the ischaemia of a cerebrovascular accident (CVA). Total serum ascorbate and malondialdehyde (MDA) were measured in 45 patients with CVA on the day of admission to hospital (Time 0) and 48 hours later (Time 48 hours) and also in 45 age and sex matched controls. There was no statistical difference in total serum ascorbate between the control group (34.2 mumol/l +/- 3.1, mean +/- SEM) and the CVA patients at Time 0 (37.3 +/- 2.9) but there was a statistically significant decrease at Time 48 hours (22.7 +/- 2.0) (p < 0.001) in the CVA patients. With MDA there was no statistical difference between the patients at Time 0 (0.79 mumol/l +/- 0.06) and the control group (0.83 +/- 0.06) but there was a significant increase at Time 48 hours (1.65 +/- 0.08) (p < 0.001). These findings are in keeping with possible evidence of free radical damage in CVA.

Reduction of free radical generation minimises lower limb swelling following femoropopliteal bypass surgery

Oxygen-derived free radicals have been implicated as contributors to the development of lower limb oedema observed after femoropopliteal bypass grafting. This study investigates the occurrence of free radical-induced lipid peroxidation after this operation and the possible effects of allopurinol (xanthine oxidase inhibitor) in reducing free radical injury in order to minimise lower leg oedema. Twenty-nine patients undergoing femoropopliteal bypass surgery were randomised in a double blind fashion into two groups; those in one were given allopurinol 200 mg orally (n = 15) at 24 h and 2 h preoperatively and again at 24 h postoperatively, while those in the second group received a placebo (n = 14). Daily lower limb volume was calculated to assess swelling. Blood samples were taken from the femoral vein for measurements of malondialdehyde (MDA), an end product of lipid peroxidation, before the application of the femoral artery clamp, just prior to and immediately after clamp release, and at 20 minute intervals thereafter for 1 hour. The increase in lower limb volume in the placebo group was almost twice (8.9 +/- 1.6%) that of the allopurinol group (4.6 +/- 1%; p = 0.02). Six out of the 14 patients receiving placebo suffered swelling of 10% or more of original lower limb volume in comparison to only one out of 15 in those given allopurinol (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)