The impact of hormone replacement therapy on the pathophysiology of peripheral arterial disease

BACKGROUND

Hormone replacement therapy (HRT) is recommended to post-menopausal women to control menopausal symptoms and prevent osteoporosis. The management of women with peripheral arterial disease (PAD) and who are taking HRT is controversial.

AIM

To summarise what is known about HRT and its effect on the natural progression of PAD and its subsequent treatment.

METHODS

A MEDLINE (1966-2004) and Cochrane library search for articles relating to HRT and PAD was undertaken.

RESULTS

The potential benefits of unopposed estrogen therapy on atherosclerotic progression and limb microcirculation are outweighed by the increased risk of endometrial dysplasia and thrombotic complications. Only one major study (Rotterdam) specifically assessed the impact of HRT on the clinical course of PAD. The findings suggested a decreased risk of PAD among healthy post-menopausal women taking HRT which contrasts with the sub-group analyses of other major studies (HERS/HERS II). HRT appears to reduce the primary success rates of both endovascular and open surgical revascularisation in patients with PAD.

CONCLUSIONS

Further studies are required to investigate the effects of HRT on the progression of PAD and its management.

Chronic venous disease in a cohort of healthy UK Asian men

OBJECTIVES

This group has previously reported that UK Asians are significantly less likely to undergo surgery for lower limb venous disease than age and sex matched Caucasians. The aim of the present study was to estimate the prevalence of lower limb chronic venous disease (CVD) in the UK Asian male population.

DESIGN

A prospective, epidemiological survey.

MATERIALS AND METHODS

100 unselected Asian men attending a local Mosque were assessed for the evidence of lower limb CVD, involving the collection of data on history and clinical signs and objective assessments of venous pathophysiology using lower limb venous ultrasonography and venous photoplethysmography (PPG).

RESULTS

On clinical examination, 80 limbs (in 50 subjects) had clinical evidence of CVD, the majority of cases consisting of varicose veins (CEAP C2). No limbs had either healed or active ulceration (C5/6), and only 2 limbs had thread veins (C1). Eight subjects had had previous venous surgery. The venous refill time (vRT) measured by PPG was lower in limbs with CVD. On venous ultrasound, reflux was present in 73/200 limbs, affecting primarily the GSV system, with only 7 limbs having deep venous reflux.

CONCLUSIONS

Present data strongly suggest that the low rates of superficial venous surgery in UK Asians is not because they are inherently less likely to develop CVD.

Obesity and Thrombosis

OBJECTIVES

To describe the pathophysiological mechanisms by which obesity increases the propensity to thrombosis, the leading cause of death in the Western World, with particular emphasis on the role of inflammation, oxidative stress, dyslipidaemia, insulin resistance and the coagulation cascade.

DESIGN

Review article.

MATERIALS AND METHODS

Medline (1966-2005) and Cochrane library review of literature examining the relationship between obesity and thrombosis. Search terms included obesity, overweight, body mass index, thrombosis, cardiovascular disease, venous thromboembolism, peripheral arterial disease, and coronary heart disease.

RESULTS

Obesity is an important and growing public health issue that is estimated to affect more than half of the UK adult population. Obesity, in particular central (visceral) obesity, is associated with significant, and largely preventable, morbidity and mortality including an increased incidence and prevalence of arterial and venous thrombotic events. The various mechanisms by which obesity may cause thrombosis include: the actions of so-called adipocytokines from adipose tissue, e.g. leptin and adiponectin; increased activity of the coagulation cascade and decreased activity of the fibrinolytic cascade; increased inflammation; increased oxidative stress and endothelial dysfunction; and disturbances of lipids and glucose tolerance in association with the metabolic syndrome.

CONCLUSIONS

Obesity appears to be associated with thrombosis via several mechanisms. These pro-thrombotic factors are all improved by weight loss.

The effect of supervised exercise and cilostazol on coagulation and fibrinolysis in intermittent claudication: A randomized controlled trial

BACKGROUND

The prothrombotic, hypofibrinolytic state that develops in patients with intermittent claudication (IC) upon walking due to ischemia-reperfusion injury (IRI) of the leg muscles may contribute to the high incidence of life- and limb-threatening thrombotic events observed in this patient group. Treatments, such as angioplasty, that obtund the IRI also ameliorate the procoagulant diathesis. The effect on this diathesis of supervised exercise and cilostazol, both of which provide symptomatic benefit in IC, but without significantly obtunding IRI, is unknown.

METHODS

Thirty-four patients (27 men and 7 women; median age, 67 years; range, 63-72 years) were randomized to receive best medical therapy (BMT) plus supervised exercise (n = 9), BMT plus cilostazol (n = 9), BMT plus supervised exercise plus cilostazol (n = 7), or BMT alone (n = 9) in a 2 x 2 factorial design. Thrombin-antithrombin complex and prothrombin fragments 1 and 2, both markers of thrombin generation; plasminogen activator inhibitor antigen and tissue plasminogen activator antigen, both markers of fibrinolysis; ankle-brachial pressure index (ABPI); and initial and absolute claudication distance (ACD) were measured at baseline and then 3 and 6 months after randomization.

RESULTS

At 6 months, when compared with receiving BMT only, supervised exercise and cilostazol resulted in improvements in ABPI of 18% and 13% and in ACD of 40% and 64%, respectively. The effects on ABPI and ACD of combining supervised exercise and cilostazol were additive. Supervised exercise, cilostazol, and supervised exercise combined with cilostazol had no significant effect on any of the four hemostatic markers.

CONCLUSIONS

Treatment of IC by supervised exercise or cilostazol results in significant improvements in ABPI and ACD but has no demonstrable effect on the prothrombotic diathesis. This suggests that supervised exercise and cilostazol, unlike angioplasty, are unlikely to have a long-term beneficial effect on the thrombotic risks faced by these patients.

Management of severe ischaemia of the leg

Prevention is better than cure

The Low Incidence of Surgery for Non-Cardiac Vascular Disease in UK Asians may be Explained by a Low Prevalence of Disease

AIMS

Firstly, to compare rates of surgery for non-cardiac vascular disease in Caucasians and Asians and secondarily to assess the prevalence of peripheral arterial disease (PAD) and abdominal aortic aneurysm (AAA) in the male UK Asian population.

METHODS

Analysis of a prospective database followed by an epidemiological survey of 100 unselected Pakistani males, in which demographic and anthropometric data were collected alongside aortic ultrasonography and measurement of ankle: brachial pressure index (ABPI).

RESULTS

Although 14.1% of our catchment area is Asian, after correction for age, they only accounted for 64/2268 (2.8%) of procedures for PAD and AAA. Specifically, Asians were 10 times less likely to undergo AAA repair and 3 times less likely to undergo procedures for lower limb peripheral bypass, amputation and endovascular intervention. In the epidemiological study, 26 subjects had a significant history of ischaemic heart disease, 21 were diabetic, 32 had hypertension and 60 were current or ex-smokers. Median aortic diameter [IQR] was 17.6 mm [16.3-19.1 mm] and no subject had an AAA. In 200 limbs, median ABPI [IQR] was 1.12 [1.04-1.21]. Only 2 patients had an ABPI < 0.9.

CONCLUSION

Despite a high prevalence of cardiovascular risk factors and ischaemic heart disease, the prevalence of PAD and AAA is much lower than would have been expected in an age- and sex-matched Caucasian population. These data suggest that the reduced incidence of surgery for PAD and AAA in UK Asians is due to a low prevalence of disease.

A comparison of the changes in generic quality of life after superficial venous surgery with those after laparoscopic cholecystectomy

BACKGROUND

Superficial venous surgery (SVS) results in a significant improvement in generic health-related quality of life (HRQL). However, it is unclear how this improvement compares with that observed after other commonly performed general and vascular operations. The aim of this study was to compare the changes in generic HRQL observed before and after SVS for CEAP clinical grade 2 to 4 venous disease with those observed before and after elective laparoscopic cholecystectomy (ELC) for biliary colic.

METHODS

The Short Form 12 questionnaire was mailed to patients before and 3, 6, and 12 months after SVS (n = 143) and ELC (n = 60). The responses were used to calculate physical (PCS) and mental (MCS) component summary scores at each time point. A higher score indicates a better HRQL.

RESULTS

Before surgery and 3 and 12 months after surgery, patients in the ELC group had a significantly lower PCS than those in the SVS group (40.2 vs 49.5, 48.9 vs 53.1, and 45.4 vs 53.8; P < .001, P = .033, and P < .001, respectively; Mann-Whitney U test). However, the change in PCS observed over the first 12 postoperative months was not significantly different between the SVS and ELC groups. Patients in the ELC group had a significantly lower MCS than those in the SVS group before surgery (45.9 vs 50.8; P = .002; Mann-Whitney U test), but not after surgery. There was no difference between the two groups in terms of postoperative change in MCS.

CONCLUSIONS

SVS is associated with a statistically significant and clinically meaningful improvement in generic HRQL that is similar to that observed after ELC. These novel data lend further support to the clinical benefit of SVS and will help health care purchasers make decisions regarding the prioritization of vascular and general surgical services.

A Comparison Between the Short Term and Long Term Benefits of Screening for Abdominal Aortic Aneurysms from the Huntingdon Aneurysm Screening Programme

BACKGROUND

The UK Multicentre Aneurysm Screening Study (MASS) showed a 44% reduction in AAA-related mortality after 4 years and predicted an increased number of deaths prevented in the longer term. We aim to compare the 5 and 13 years benefit from aneurysm screening in the Huntingdon Aneurysm screening programme.

METHODS

Incidence and mortality of ruptured AAA (RAAA) after 5 and 13 years of screening in a population based aneurysm screening program.

RESULTS

Five years of screening resulted in a reduction in the incidence of RAAA of 49% (95% CI: 3-74%). Nine out of 11 ruptures in the invited group did not survive (mortality 82%; 95% CI: 48-98%) compared to 38 non-survivors from 51 ruptures in the control group (mortality 75%; 95% CI: 60-86%). Five years of screening resulted in an RAAA-related mortality reduction of 45% (95% CI: -15 to 74%). After 13 years of screening the incidence of RAAA was reduced by 73% (95% CI: 58-82%). Twenty-one out of 29 ruptures in the invited group did not survive (mortality 72%; 95% CI: 53-87%) compared to 64 non-survivors from 82 ruptures in the control group (mortality 78%; 95% CI: 68-86%). Thirteen years screening resulted in a reduction of mortality from RAAA of 75% (95% CI: 58-84%). The number needed to screen to prevent one death reduced from 1380 after 5 years to 505 after 13 years. The number of elective AAA operations needed to prevent one death reduced from 6 after 5 years to 4 after 13 years.

CONCLUSION

AAA screening becomes increasingly beneficial as screening continues over the longer term. Benefits continue to increase after screening has ceased.

Hypotensive Resuscitation in Patients with Ruptured Abdominal Aortic Aneurysm

BACKGROUND

The technique of hypotensive resuscitation in haemorrhagic shock involves resuscitation to below normotensive blood pressures achieving the minimum perfusion pressure that will adequately perfuse vital organs until definitive arrest of haemorrhage.

AIM

To summarise the evidence for the use of hypotensive resuscitation in patients with uncontrolled haemorrhagic shock and ruptured abdominal aortic aneurysm (AAA).

METHODS

A MEDLINE (1966-2004) and Cochrane library search for articles relating to hypotensive resuscitation was undertaken; see text for further details.

RESULTS

Several animal studies exist using an abdominal aortotomy model of ruptured AAA. These have demonstrated improved tissue perfusion, decreased blood loss and improved survival associated with hypotensive resuscitation compared with aggressive resuscitation. There are several human studies advocating delayed rather than immediate resuscitation in trauma patients but careful review of the literature reveals no prospective studies of hypotensive resuscitation in patients with ruptured AAA.

CONCLUSIONS

Animal studies demonstrate superiority of hypotensive resuscitation over aggressive resuscitation but further research is required to assess its efficacy in patients with ruptured AAA.

Digital venous photoplethysmography in the seated position is a reproducible noninvasive measure of lower limb venous function in patients with isolated superficial venous reflux

BACKGROUND

The value of photoplethysmography (PPG) has been questioned because of a lack of reproducibility. We performed this study to determine whether new digital technology has improved the reproducibility of PPG in the noninvasive assessment of lower limb venous function in patients with isolated superficial venous reflux.

METHODS

This was a prospective study of 140 legs in 110 patients (65% female; median age [interquartile range], 45 years [36-59.25 years]; CEAP clinical grade C2/3, n = 114; C4-6, n = 26) who underwent repeated digital PPG measurements of refilling time (RT) in both the sitting and standing position after standard exercise regimens by a single observer. RT was measured in all patients 2 to 5 minutes apart and in a randomly selected subgroup of 30 patients (38 limbs) 1 to 2 weeks apart. RT variability was assessed by using Bland and Altman's coefficient of repeatability (CR-RT), where the CR-RT was 1.96 times the standard deviation of the mean difference in RT between two tests. Venous duplex scanning of both the deep and superficial veins was also performed, and a reverse flow of greater than 0.5 seconds was considered abnormal. Only patients with isolated superficial venous reflux were included in the study.

RESULTS

The CR-RT of the tests on 140 limbs performed 2 to 5 minutes apart was 10 seconds overall, 3 seconds for RT up to 10 seconds, and 16 seconds for RT between 20 and 40 seconds. The CR-RT of the 38 tests performed 1 to 2 weeks apart was also 10 seconds. No systematic variation due to a nonrandom error was found between the measurements performed either 2 to 5 minutes or 1 to 2 weeks apart.

CONCLUSIONS

Digital PPG performed in the seated position in patients with isolated superficial venous reflux provides a reproducible method for the noninvasive assessment of lower limb venous function for both clinical and research purposes. However, the variation in precision of RT with the magnitude of the measurement must be taken into account when results are interpreted in individual patients.

The constitutive procoagulant and hypofibrinolytic state in patients with intermittent claudication due to infrainguinal disease significantly improves with percutaneous transluminal balloon angioplasty

BACKGROUND

Patients with intermittent lower limb claudication (IC) exhibit a prothrombotic diathesis that is acutely exacerbated by exercise. This may occur because of ischemia/reperfusion injury within the leg muscles during walking and may contribute to the increased risk of thrombotic vascular events in this group of patients. This randomized study compared the effect of lower limb revascularization by percutaneous transluminal balloon angioplasty (PTA), supervised exercise, and best medical therapy (BMT) alone on this prothrombotic state.

METHODS

Twenty-three patients (16 men and 7 women; median age, 67 years; range, 57-77 years) with IC due to infrainguinal disease were randomized to receive BMT alone (n = 7), BMT plus PTA (n = 9), or BMT plus supervised exercise (n = 7) as part of the Health Technology Assessment-funded EXercise vs Angioplasty in Claudication Trial (EXACT). Patients were assessed at baseline and at 3 and 6 months. Thrombin-antithrombin complex (TAT) was determined as a marker of thrombin generation, and plasminogen activator inhibitor (PAI) antigen was determined as a marker of fibrinolysis. Increased TAT indicates a procoagulant state, and increased PAI antigen indicates a hypofibrinolytic state.

RESULTS

At 6 months, subjects randomized to BMT plus PTA demonstrated a significant improvement in ankle-brachial pressure index (P = .013) and maximal walking distance (P = .008), a significant decline in resting thrombin generation (median [interquartile range] TAT, 6.4 microg/L [2.7-13.5 microg/L] to 1.5 microg/L [0.3-2.9 microg/L]; P = .038), and an improvement in resting fibrinolysis (median [interquartile range] PAI-1, 10.0 ng/mL [1.0-20.5 ng/mL] to 1.0 ng/mL [1.0-14.8 ng/mL]; P = .043). There was no significant change in any of these parameters in patients randomized to BMT plus supervised exercise or to BMT alone.

CONCLUSIONS

The addition of lower limb revascularization by PTA to BMT in patients with IC due to infra-inguinal disease results in a medium-term improvement in the resting procoagulant and hypofibrinolytic state. This may translate into a reduction in morbidity and mortality from thrombotic vascular events in this group of patients.

Bypass versus angioplasty in severe ischaemia of the leg (BASIL): multicentre, randomised controlled trial

BACKGROUND

The treatment of rest pain, ulceration, and gangrene of the leg (severe limb ischaemia) remains controversial. We instigated the BASIL trial to compare the outcome of bypass surgery and balloon angioplasty in such patients.

METHODS

We randomly assigned 452 patients, who presented to 27 UK hospitals with severe limb ischaemia due to infra-inguinal disease, to receive a surgery-first (n=228) or an angioplasty-first (n=224) strategy. The primary endpoint was amputation (of trial leg) free survival. Analysis was by intention to treat. The BASIL trial is registered with the National Research Register (NRR) and as an International Standard Randomised Controlled Trial, number ISRCTN45398889.

FINDINGS

The trial ran for 5.5 years, and follow-up finished when patients reached an endpoint (amputation of trial leg above the ankle or death). Seven individuals were lost to follow-up after randomisation (three assigned angioplasty, two surgery); of these, three were lost (one angioplasty, two surgery) during the first year of follow-up. 195 (86%) of 228 patients assigned to bypass surgery and 216 (96%) of 224 to balloon angioplasty underwent an attempt at their allocated intervention at a median (IQR) of 6 (3-16) and 6 (2-20) days after randomisation, respectively. At the end of follow-up, 248 (55%) patients were alive without amputation (of trial leg), 38 (8%) alive with amputation, 36 (8%) dead after amputation, and 130 (29%) dead without amputation. After 6 months, the two strategies did not differ significantly in amputation-free survival (48 vs 60 patients; unadjusted hazard ratio 1.07, 95% CI 0.72-1.6; adjusted hazard ratio 0.73, 0.49-1.07). We saw no difference in health-related quality of life between the two strategies, but for the first year the hospital costs associated with a surgery-first strategy were about one third higher than those with an angioplasty-first strategy.

INTERPRETATION

In patients presenting with severe limb ischaemia due to infra-inguinal disease and who are suitable for surgery and angioplasty, a bypass-surgery-first and a balloon-angioplasty-first strategy are associated with broadly similar outcomes in terms of amputation-free survival, and in the short-term, surgery is more expensive than angioplasty.

Treatment for diabetic foot ulcers

People with diabetes develop foot ulcers because of neuropathy (sensory, motor, and autonomic deficits), ischaemia, or both. The initiating injury may be from acute mechanical or thermal trauma or from repetitively or continuously applied mechanical stress. Patients with clinically significant limb ischaemia should be assessed by a vascular surgeon to determine the need for angioplasty, stenting, or femorodistal bypass. When infection complicates a foot ulcer, the combination can be limb or life-threatening. Infection is defined clinically, but wound cultures reveal the causative pathogens. Tissue specimens are strongly preferred to wound swabs for wound cultures. Antimicrobial therapy should be guided by culture results, and should aim to cure the infection, not to heal the wound. Alleviation of the mechanical load on ulcers (off-loading) should always be a part of treatment. Neuropathic ulcers typically heal in 6 weeks with total contact casting, because it effectively relieves pressure at the ulcer site and enforces patient compliance. The success of other approaches to off-loading similarly depends on the patients' adherence to the effectiveness of pressure relief. Surgery to heal ulcers and prevent recurrence can include tenotomy, tendon lengthening, reconstruction, or removal of bony prominences. However, these procedures may result in secondary ulceration and other complications. Ulcer recurrence rates are high, but appropriate education for patients, the provision of posthealing footwear, and regular foot care can reduce rates of re-ulceration.

Serum lactate and base deficit as predictors of mortality after ruptured abdominal aortic aneurysm repair

OBJECTIVE

Whole body hypoperfusion and lower torso ischaemia-reperfusion contribute to post-operative organ dysfunction in patients undergoing repair of ruptured abdominal aortic aneurysm (AAA). Serum lactate and base deficit are markers of tissue ischaemia and are used to assess the adequacy of resuscitation. This study examines the prognostic value of immediate post-operative levels of serum lactate and base deficit in ruptured AAA.

METHODS

Thirty patients (24 men and 6 women of median age 74, range 51-85, years) who survived to at least 12h after ruptured AAA repair were studied retrospectively. The relationship between immediate post-operative lactate, base deficit and mortality was determined.

RESULTS

Fifteen patients (50%) died, all from organ failure. An elevated lactate (>2.1 mmol/l) and base deficit (<-2 mmol/l) were present in 20 (67%) and 27 (90%) patients, respectively. Lactate (p<0.001) and base deficit (p=0.003) were significantly higher in non-survivors compared with survivors. Lactate (p=0.021) and base deficit levels (p=0.028) were independently significant for predicting mortality and a significant interaction existed between lactate and base deficit levels for predicting mortality (p=0.027). The sensitivity and specificity of lactate > or =4.0 mmol/l was 13 of 15 (87%) and 12 of 15 (80%), respectively, and base deficit < or =-7 mmol/l was 12 of 15 (80%) and 12 of 15 (80%), respectively. The likelihood ratios for a positive result with the defined cut-off values for lactate and base deficit were 4.3 and 4.0, respectively. Lactate > or =4.0 mmol/l and base deficit <or =-7 mmol/l were associated with a 94.5% probability of death while lactate < or =4.0 mmol/l and base deficit > or =-7 mmol/l were associated with a 4% probability of death.

CONCLUSION

These data demonstrate that an immediate post-operative serum lactate > or =4.0 mmol/l and base deficit < or =-7 mmol/l are good predictors of outcome after ruptured AAA repair. The prognostic value of these simple and inexpensive tests require corroboration in a larger prospective study.