The role of venous diameter in predicting arteriovenous fistula maturation: when not to expect an AVF to mature according to pre-operative vein diameter measurements? A best evidence topic.

This best evidence topic was investigated according to a described protocol. We asked the question: what is the minimal vein diameter that can successfully predict maturation of an arteriovenous fistula (AVF) in patients undergoing dialysis. Using the reported search 804 papers were found, of which five represented the best evidence to answer the clinical question. All studies assessed the association between successful AVF maturation and the size of vein used. The strongest evidence came from a nonrandomised controlled follow-up study in which 76% of fistulas created using >2 mm cephalic vein successfully matured compared to 16% when the vein measured ≤2 mm. Another prospective, multicentre study showed 65% successful maturation using veins >4 mm compared to 45% with veins <3 mm. Vein diameter was found to be an independent predictor of maturation in multivariate regression analysis in two retrospective observational studies. Another retrospective observational study found that using venous measurements of ≥2.5 mm following tourniquet application resulted in more fistulas been created that would have otherwise been denied based on venous ultrasound mapping. A large multicentre randomised clinical trial assessing the use of different vein sizes both with and without tourniquet application using proper statistical tools - such as receiver operating characteristic - is required to make a final recommendation. Until then, a vein diameter of <2.5 mm should be considered inadequate for formation of an AVF, particularly if those measurements remain unchanged following the use of tourniquet.

Assessing the quality of online information for patients with carotid disease.

INTRODUCTION: Controversy exists relating to carotid endarterectomy (CEA) versus carotid artery stenting (CAS). We aimed to assess the quality of online patient information relating to both. METHODS: The Google search engine was searched for "carotid endarterectomy" and "carotid stenting". The first 50 webpages returned were assessed. The Gunning Fog Index (GFI) and Flesch Reading Ease Score (FRES) were calculated to assess readability. The LIDA tool (Minervation Ltd., Oxford, U.K.) was used to assess accessibility, usability and reliability. RESULTS: 20% (n = 10) of the webpages returned for CEA were from peer reviewed sources with 34% (n = 17) posted by hospitals or health services. Comparatively, for CAS, 40% (n = 20) were peer reviewed with 16% (n = 8) posted by hospitals or health services. GFI and FRES scores indicated webpages for both CEA and CAS had poor general readability. Webpages for CEA were easier to read than those for CAS (mean FRES difference of 6.7 (95% CI 0.51 to 12.93, p = 0.03). Median LIDA scores demonstrated acceptable reliability, accessibility and usability of information for both CEA and CAS webpages. The more readable webpages were not associated with higher LIDA scores for either CEA or CAS webpages. CONCLUSION: Webpages providing information on carotid disease management must be made more readable. Online information currently available to patients regarding CAS is more difficult to read and comprehend than CEA.

The impact of regional reconfiguration on the management of appendicitis.

BACKGROUND: Reconfiguration of surgical services in the Mid-West in 2009 resulted in a large increase in numbers of patients undergoing emergency surgery for appendicitis in University Hospital Limerick (UHL). AIMS: The aim of this study was to assess the impact of reconfiguration on the management of appendicitis in this area. METHODS: Data on all patients who underwent appendicectomy between January and June 2007 were compared with the corresponding data from January to June 2011. The numbers of operations, types of operations, lengths of stay (LOS), operation start times, rates of negative histology specimens and readmissions within 30 days were compared. One hundred and twenty-five appendicectomies [48 laparoscopic (38.4 %)] were performed in the 2007 group of which 32 specimens (25.6 %) were histologically negative. Three hundred and nineteen appendicectomies [238 laparoscopic (74.6 %)] were performed in the 2011 group of which 62 specimens (19.4 %) were histologically negative. The increase in numbers of laparoscopic procedures was significant (p < 0.001). The reduction in the negative appendicectomy rate was not statistically significant (p = 0.16). There were 10 conversions (20.8 %) to open surgery in the 2007 period and 12 (5 %) in the 2011 period (p = 0.001). Mean LOS for the 2007 and 2011 groups was 4.45 and 3.16 days (p < 0.001). Six (4.8 %) readmissions within 30 days occurred in the 2007 group with 20 (6.3 %) in the 2011 group (p = 0.66). CONCLUSION: Though reconfiguration of surgical services has resulted in a significant increase in workload, LOS has decreased significantly while maintaining acceptably low negative appendicectomy, conversion and readmission rates.

Can augmentation index be used as an accurate tool in the diagnosis of peripheral obstructive arterial disease?

BACKGROUND: The use of radial augmentation index (rAI) as an indicator of vascular disease was investigated in the vascular imaging laboratory in a regional hospital. AIMS: The aim of this study was to investigate whether a correlation exists between ankle-brachial pressure index (ABPI) and rAI in normal subjects, patients with peripheral obstructive arterial disease, and diabetic patients. METHODS: A group of 46 patients and 14 controls had ABPI and rAI measured and factors affecting AI were assessed. RESULTS: rAI was found to have a negative correlation with ABPI (Spearman's ρ = -0.513, p < 0.01). There was significant increase in the rAI scores of diabetic patients compared to normal patients (normal median was 64% lower than diabetic median, p < 0.01) and in peripheral obstructive vascular disease patients compared to normal (normal median 69% lower, p < 0.001). Of the various affecting factors, age stood out with rAI having a positive correlation to age (Spearman's ρ = 0.68, p < 0.01). CONCLUSIONS: The augmentation index appears be a significant indicator of cardiovascular disease and may be a useful tool in the diagnosis of vascular pathology.

Wall shear stresses remain elevated in mature arteriovenous fistulas: a case study.

Maintaining vascular access (VA) patency continues to be the greatest challenge for dialysis patients. VA dysfunction, primarily due to venous neointimal hyperplasia development and stenotic lesion formation, is mainly attributed to complex hemodynamics within the arteriovenous fistula (AVF). The effect of VA creation and the subsequent geometrical remodeling on the hemodynamics and shear forces within a mature patient-specific AVF is investigated. A 3D reconstructed geometry of a healthy vein and a fully mature patient-specific AVF was developed from a series of 2D magnetic resonance image scans. A previously validated thresholding technique for region segmentation and lumen cross section contour creation was conducted in MIMICS 10.01, allowing for the creation of a 3D reconstructed geometry. The healthy vein and AVF computational models were built, subdivided, and meshed in GAMBIT 2.3. The computational fluid dynamic (CFD) code FLUENT 6.3.2 (Fluent Inc., Lebanon, NH) was employed as the finite volume solver to determine the hemodynamics and shear forces within the healthy vein and patient-specific AVF. Geometrical alterations were evaluated and a CFD analysis was conducted. Substantial geometrical remodeling was observed, following VA creation with an increase in cross-sectional area, out of plane curvature (maximum angle of curvature in AVF=30 deg), and angle of blood flow entry. The mean flow velocity entering the vein of the AVF is dramatically increased. These factors result in complex three-dimensional hemodynamics within VA junction (VAJ) and efferent vein of the AVF. Complex flow patterns were observed and the maximum and mean wall shear stress (WSS) magnitudes are significantly elevated. Flow reversal was found within the VAJ and efferent vein. Extensive geometrical remodeling during AVF maturation does not restore physiological hemodynamics to the VAJ and venous conduit of the AVF, and high WSS and WSS gradients, and flow reversal persist. It is theorized that the vessel remodelling and the continued non-physiological hemodynamics within the AVF compound to result in stenotic lesion development.

Improved assessment and treatment of abdominal aortic aneurysms: the use of 3D reconstructions as a surgical guidance tool in endovascular repair.

BACKGROUND: Endovascular repair is fast becoming the treatment of choice for abdominal aortic aneurysms in anatomically suitable patients. 3D reconstructions not only aid conventional 2D measurements but also allow further analyses of the vessel anatomy. METHODS: Computed tomography scan data for four male patients awaiting endovascular repair were obtained. 3D reconstructions were performed to determine measurements. Wall stress was determined on one particular case using finite element analysis. RESULTS: 3D reconstruction allows measurements to be obtained that can be difficult to determine using 2D images. This method complements traditional 2D approaches. Reconstructions also provided imaging of potential anatomical problems. Wall stress results showed key regions that may be possible rupture sites. CONCLUSION: 3D reconstructions greatly aid surgical planning. As stent-graft devices evolve, anatomical difficulties previously considered contraindications to endovascular repair can now be overcome with careful planning. 3D reconstruction is a useful adjunct to assessment and planning of endovascular repair.

Vascular trauma in an Irish regional hospital.

BACKGROUND: Vascular trauma is a common cause of mortality and morbidity worldwide. There are few accurate quantitative data available presently on the nature and outcome of these injuries. The aim of this study was to determine the incidence, aetiology, management and outcome of vascular injuries which required surgical intervention at a regional vascular unit. METHODS: All patients who suffered a vascular injury requiring surgical intervention between January 1992 and December 2005 were included. RESULTS: A total of 35 patients who underwent operative intervention for vascular trauma were reviewed. There were 26 men and 9 women with a median age of 26 years (range 3-80 years). Road traffic accidents accounted for 15 (43%) of all cases and 16 patients (47%) had an associated fracture. The brachial artery was most frequently injured, constituting 36% of all cases. Interposition grafting using the autogenous long saphenous vein was the most common procedure performed (11 patients). Eleven patients required a secondary procedure while the overall limb amputation rate was 8.5%. There was one mortality following an IVC injury. Seventy-four per cent of the cohort was asymptomatic at last follow-up. CONCLUSION: While vascular trauma is relatively uncommon in our catchment area it can be successfully managed. Most of the cases occur in young fit patients.

Natural history and clinical outcome of patients with documented carotid artery occlusion.

BACKGROUND: An occluded internal carotid artery (ICA) is considered a "safe artery" as it causes few symptoms. However, it has recently been suggested that spontaneous recanalisation of ICA occlusions may occur. AIM: To determine the incidence of ICA recanalisation among patients with a previously documented occluded ICA. METHODS: Patients with a documented ICA occlusion between September 2001 and January 2003 were identified. Patients who consented to participate had carotid duplex scans performed. Demographic and clinical data were collected. Statistical analyses were performed as appropriate. RESULTS: The total number of carotid duplex scans performed during the original study period was 719. An occluded ICA was identified in 30 (4.2%) patients. Of 19 patients who were rescanned two (11%) had recanalised a previously occluded ICA. CONCLUSIONS: Recanalisation occurs in a small number of patients who may need long-term surveillance.

Mobility in patients with venous leg ulceration.

OBJECTIVES: To compare mobility in patients with venous leg ulcers to matched controls and determine the influence of mobility, age and ulcer size on ulcer healing. METHODS: 25 leg ulcer patients, and 25 matched controls wore a mobility monitor (ActivPAL, PAL Technologies Ltd, Glasgow, Scotland)) which recorded the number of steps and amount of time spent walking, standing, sitting or lying for a one-week period. A walking index was calculated. The ulcer group were treated with compression bandaging and ulcer healing recorded over 12 weeks. RESULTS: There were 13 female subjects in each group. The median age was 70.5 (range 30-89) years. There was no difference in the amount of time either group spent standing, walking and resting. There was a significant reduction in the number of steps taken and in the walking index in the ulcer group compared to controls (ulcer group, median 6,685 steps/day, range 2074-17,999; control group median 8750, range 4917-16,043, p<0.05, Mann Whitney u test). Smaller ulcers and ulcers of recent onset were most likely to heal within 12 weeks (p=0.005 and p=0.011 respectively, Chi squared test). The percentage of time spent mobilising and resting did not influence ulcer healing (r(s)=-0.125; p=0.55). CONCLUSIONS: Mobility patterns among patients with leg ulcers are not significantly different to age matched controls. Ulcer patients take fewer steps per week compared to controls indicating they have reduced calf muscle pump function. Further studies are required to determine whether therapies which increase calf muscle activity have a role in ulcer treatment.

Does size matter? The impact of calf muscle volume on venous return in patients with venous leg ulcers.

OBJECTIVES: The calf muscle pump is recognized as an integral component of effective venous return from the lower limbs. The aim of this study was to determine if there is a correlation between calf muscle volume and venous blood flow among patients with venous leg ulcers. METHODS: Nine patients with venous leg ulceration were recruited for this study. These patients underwent haemodynamic testing using duplex ultrasound to measure peak venous velocities in response to voluntary maximum plantar flexion, with and without compression bandaging. Each patient then had magnetic resonance imaging (MRI) of the lower limbs. Calf muscle volume was calculated from the MRI images using a specially designed Matlab computer program to identify and count muscle pixels. Analyses applied Pearson's correlation coefficient to determine correlation between calf muscle volume and mean peak venous velocities in response to voluntary contraction. RESULTS: No correlation was seen between calf muscle volume and haemodynamic venous return in response to voluntary contraction, with or without compression bandaging. CONCLUSION: The volume of calf muscle available for promoting venous return alone may not be an accurate indicator of muscle functioning capability.

Popliteal-to-distal artery bypass for diabetic limb salvage.

BACKGROUND: Poor long-term survival and significant co-morbidity among diabetic patients with limb ischaemia makes the shortest, simplest revascularisation procedure desirable. AIM: Evaluate limb salvage, primary graft patency and peri-operative morbidity rates in diabetic patients undergoing popliteal-to-distal artery bypass for limb salvage. METHODS: Patients undergoing popliteal-to-distal artery bypass for critical limb ischaemia over a seven-year period were retrospectively identified. Patients operative and follow-up data were entered into a database and limb salvage and patient survival determined using Kaplan Meier survival analysis. RESULTS: During the study period 21 popliteal-to-distal artery bypasses were performed on 19 diabetic patients. Mortality rate after one year was 11%. Primary graft patency rates among surviving patients was 81%, 67% and 48% at 1, 2 and 6 years respectively. Amputation was required in three patients. CONCLUSION: Popliteal-to-distal artery bypass produces favourable results in high-risk diabetic patients with critical limb ischaemia.

Local anaesthetic flush reduces postoperative pain and haematoma formation after great saphenous vein stripping--a randomised controlled trial.

OBJECTIVES: To observe the effect of local anaesthetic flush through the great saphenous vein (GSV) tunnel on postoperative pain and haematoma formation following saphenous vein stripping operations. DESIGN: Prospective, double-blind, randomised, control trial. METHODS: One hundred patients were randomized to receive 20 ml of local anaesthetic (bupivacaine 0.25% + adrenaline) or saline control flush through the GSV tunnel after stripping in a double-blind study. Visual analogue pain scores were used to measure postoperative pain daily for the 1st week, then at 3 weeks and 6 weeks. Patients were examined during the 1st, 3rd and 6th week for haematoma formation. RESULTS: In the control group the median postoperative pain score was 4 (range 0-7) in the immediate postoperative period compared to a median of 1 (range 0-4) in the LA group (p<0.001). The median pain score on day-4 was 4 (range 1-6) (control) vs. 1 (range 0-3) (LA group) (p<0.001, Mann-Whitney Utest) and on day-6 it was 1 (range 0-5) (control) vs. 0 (range 0-5) (LA group) (p<0.001, Mann-Whitney). Twelve patients (24%) developed a haematoma in the GSV tunnel in the control group compared to three patients (6%) in the LA group (p = 0.007). CONCLUSION: Flushing of the GSV tunnel with bupivacaine plus adrenaline significantly reduces postoperative pain and haematoma formation in patients undergoing GSV stripping for varicose veins.

Haemodynamic study examining the response of venous blood flow to electrical stimulation of the gastrocnemius muscle in patients with chronic venous disease.

OBJECTIVES: The aim of this study was to explore the option of stimulating calf muscle contraction through externally applied neuromuscular electrical stimulation (NMES) and to measure venous blood flow response to this stimulation. METHODS: Ten patients with class 6 chronic venous disease (CEAP clinical classification) were recruited. Measurements of peak venous velocities in the popliteal vein were recorded by Duplex scanning in response to six test conditions; 1. Standing, 2. Voluntary calf muscle contraction, 3. Standing with NMES applied, 4. Standing with compression bandaging applied to the leg, 5. Voluntary calf muscle contraction with compression bandaging applied to the leg, 6. Stationary with compression bandaging applied to the leg and NMES applied. Comfort assessment was completed using visual analogue scales at each test stage and on study completion each patient completed a short structured interview to determine comfort and acceptability of NMES. Statistical analyses were carried out using SPSS, Version 9. Non-parametric testing was used in all analyses using the Wilcoxon Signed Ranks Test for paired samples. RESULTS: There was a significant increase in venous velocities on voluntary contraction of the calf muscle (median resting vel 7.3 cm/s; voluntary contraction median 70 cm/s) and with the introduction of NMES, both with compression (median velocity 15 cm/s, p = 0.005 Wilcoxon) and without compression (median velocity 13 cm/s, p = 0.005 Wilcoxon). The greatest increase with NMES was when combined with compression bandaging. All patients reported the stimulus as an acceptable treatment option with 90% reporting NMES as comfortable. CONCLUSIONS: Healing rates in venous ulceration with the application of compression bandaging remain between 50 and 70%. This study shows a positive haemodynamic response to NMES. Further research is needed to quantitatively measure the effect of NMES on ulcer healing.

Health-related quality of life during four-layer compression bandaging for venous ulcer disease: a randomised controlled trial.

BACKGROUND: Venous leg ulceration is a chronic debilitating condition which negatively impacts on patients' quality of life. Despite the application of gold standard treatment a number of patients suffer from 'slow to heal' ulcers, which can require treatment for years. AIMS: The aim of this study was to compare the effects of four-layer compression bandaging (4LB) for treating venous leg ulcers with other available treatments on health-related quality of life duringtreatment. METHODS: In this pragmatic trial, 200 patients with venous leg ulceration were randomised either to 4LB (intervention group; n = 100) or to continue their usual system of care (control group; n = 100). Analysis was by intention to treat; quality of life measurements were taken at randomisation and after six weeks of treatment. RESULTS: 4LB provided greater quality of life benefits than the control group particularly in the area of physical activity and social functioning. CONCLUSION: Due to the long-term nature of treatment for many of these patients, the effects on quality of life should be considered when prescribing treatment. This study has shown that 4LB significantly improves the quality of life of patients during treatment for venous leg ulceration.

Information leaflets for venous leg ulcer patients: are they effective?

OBJECTIVE: To validate the usefulness of written information for patients with venous leg ulcers and test the hypothesis that patients who receive written information retain more knowledge than those who receive verbal information alone. METHOD: Twenty patients newly diagnosed with venous leg ulcers were recruited into this prospective trial. Patients were randomised either to the control group (given verbal information on their condition) or the intervention group (same verbal information and an information leaflet). The verbal information was in the same format as in the leaflet. Patients' knowledge of the condition was ascertained at an initial interview and at follow-up four to six weeks later. RESULTS: At follow-up both groups showed an overall improvement in knowledge, with no statistical difference between them. CONCLUSION: The results indicate there is limited value in providing information leaflets to this patient group, who were predominantly older patients with low levels of education. The relatively small sample size may explain the disappointing results. Further research may reveal a benefit of providing these leaflets to carers.

A review of technological approaches to venous ulceration.

Leg ulceration is a chronic condition affecting about 1-2% of the adult population. The main causes of leg ulceration are venous hypertension, arterial insufficiency, diabetes, or a combination of these aetiologies (causes) or malignancy. Venous ulcers account for approximately 80% of all leg ulcers and are a result of venous hypertension. The current mainstay of treatment of venous ulcers is the application of graduated compression bandaging to the limb. In spite of the application of the best evidence-based therapy, healing rates for venous leg ulcers remain disappointing, at 50-70% after 12 weeks of treatment, depending on initial size and chronicity of the ulcer. Thus, a large number of ulcers are unhealed by this time, and many patients suffer from long-term leg ulceration, some remaining for years, and those that heal often recur. There is an obvious need to develop new treatments that would improve healing rates. This review provides a complete overview of the anatomy of venous circulation and the physiology pertaining to it, the pathophysiology of venous disease, the pathogenesis of ulceration, and a review of treatments currently employed in healing venous leg ulcers and their supporting evidence. The aim of this article is to encourage a fresh look at this chronic problem and stimulate ideas on how healing rates can be improved.

Randomized clinical trial and economic analysis of four-layer compression bandaging for venous ulcers.

BACKGROUND: The aim of this study was to compare the cost-effectiveness of four-layer compression bandaging for venous leg ulcers with that of other available treatments. METHODS: In this pragmatic trial, 200 patients with a venous leg ulcer were randomized either to four-layer bandaging (intervention group; n = 100) or to continue their usual system of care (control group; n = 100). The follow-up for each patient was 12 weeks. Analysis was by intention to treat; the main outcome measures were time to healing and cost to the health board per leg healed. RESULTS: Baseline characteristics were well matched in the two groups. The Kaplan-Meier estimate of the healing rate at 3 months was 54 per cent with four-layer bandaging and 34 per cent in the control group. Throughout the 3 months, four-layer bandaging healed leg ulcers significantly earlier (P = 0.006). There was a significant reduction in the median cost per leg healed with four-layer bandaging (euro 210 versus euro 234; P = 0.040). CONCLUSION: Four-layer bandaging is currently the most effective method of treating venous leg ulcers in a community setting.

Endovascular exclusion of iliac artery to iliac vein fistula after lumbar disk surgery.

Iliac arteriovenous (AV) fistula is rare after lumbar disk surgery. Traditionally, open repair through the arterial lumen was performed. We report endovascular exclusion of an iliac AV fistula in a 41-year-old woman 8 years after lumbar diskectomy. An angiogram showed an AV fistula connecting the right common iliac artery and vein. This was repaired with placement of two covered wall stents in the right common artery and external iliac artery, and embolization of the right internal iliac artery. Contrast medium-enhanced computed tomography scan at 5 months confirmed elimination of the AV fistula and right iliac artery patency. This technique should be considered in management of iliac AV fistulas.

Critical appraisal of the application of carotid duplex scanning.

AIMS: To evaluate the indications for carotid arterial imaging in an open access vascular laboratory. To identify those symptoms predictive of > 50% stenosis of the carotid artery in order to reduce unnecessary imaging. To test the hypothesis that duplex scanning would not be of significant benefit in the management of those patients with ill defined symptoms. METHODS: We compared the outcome of carotid duplex scanning performed on 816 consecutive patients referred for a variety of clinical indications. The medical records of 816 patients were retrospectively analysed to identify the clinical indication for carotid duplex imaging over a three-year period (1997-9). RESULTS: The indications for duplex imaging were divided into two groups: definite carotid symptoms, n=350 (transient ischaemic attack n=205, cerebrovascular accident n=66, amaurosis fugax n=49, dysphasia n=30); and non-carotid symptoms, n=466 (dizziness n=63, syncope n=63, confusion n=20, vertigo n=10 and others n=310). Less than 5% of those with definite carotid symptoms and 2% of those with ill-defined symptoms had a stenosis > 80%. CONCLUSION: Regardless of symptoms, 14% and 2.9% of patients referred for carotid duplex imaging have a stenosis of > or = 50% and > or = 80%, respectively. Patients without definite carotid symptoms are of low priority for duplex imaging.

Regional vascular surgical units: a practical means of providing specialist services.

BACKGROUND: A comprehensive regional emergency and elective vascular surgical service was established in Limerick Regional General Hospital between 1994 and 1996 following the appointment of three surgeons with vascular training. AIM: To compare vascular surgical activity before and after the establishment of a regional vascular service. METHODS: This study used local and national computerised databases, clinic letters, theatre registers and radiology records to compare vascular surgical activity before (1992) and after (1997) this service was established. RESULTS: Total outpatient activity increased almost six-fold and total number of inpatient vascular procedures (including radiological) increased from 146 to 432, but the venous proportion declined from 70% to 36%. The number of major arterial procedures increased from 37 to 165 in 1997 including 10 carotid endarterectomies, 24 aortic reconstructions and 54 lower limb reconstructions representing rates of 3/100,000, 8/100,000 and 17/100,000 population respectively. CONCLUSION: As substantial changes in disease patterns are unlikely, these data indicate that patients previously diverted elsewhere for therapy are now cared for within the health board region and that further increases in workload may be expected. We suggest that these data mandate the reallocation of resources to fund appropriately staffed and audited regional vascular units.