Distal revascularisation with interval ligation (DRIL): an experience.

INTRODUCTION: The global increase of chronic renal failure has resulted in a growing number of patients on haemodialysis using arteriovenous fistulas (AVFs). By virtue of their very function, AVFs at times shunt blood away from regions distally, resulting in an ischaemic steal syndrome. Distal revascularisation with interval ligation (DRIL) has been described as a procedure to treat symptomatic ischaemic steal. We present our experience in the management of this complication. PATIENTS AND METHODS: Six patients with severe ischaemic steal were treated using a DRIL procedure between May 2004 and June 2007. There were three males and three females, all with elbow brachiocephalic AVFs. Symptoms ranged from severe rest pain to digital gangrene. Published results from international studies of 135 DRIL procedures were also reviewed. RESULTS: Vascular access was maintained along with the elimination of ischaemic symptoms in the six patients using an ipsilateral reversed basilic vein graft. Interval ligation of the distal brachial artery was performed at the same time. All patients showed immediate and sustained clinical improvement of symptoms with a demonstrable increase in digital pulse oximetry. CONCLUSIONS: DRIL is a beneficial treatment option that has proven successful at alleviating ischemic steal symptoms and preserving vascular access. This avoids placement of central lines, its associated risks, and the need to create an alternative sited fistula.

Primary patency rates of AV fistulas and the effect of patient variables.

BACKGROUND: DOQI (The Dialysis Outcomes Quality Initiative) recommend 40% of prevalent renal failure patients should be undergoing hemodialysis (HD) using autogenous arteriovenous fistulae (AVF). The aim of this study is to assess the primary patency rates of wrist and elbow fistulae, and to examine how patient variables influence the success of a fistula. In addition, an attempt has been made to address the main issue of survival rates in this high risk patient population. METHODS: A retrospective study was performed on all patients in the University Hospital of North Staffordshire who underwent creation of a wrist or elbow fistula for HD. During the study period 289 primary AVFs were created. In all, 210 AVF were sited at the wrist and 79 at the elbow. Follow-up ranged from 3 months to 4 yrs. Primary patency and patient death, transplant and transfer were taken as end points. Patient survival was defined as time of fistula creation to patient death. Actuarial survival was calculated using Kaplan-Meier survival analyses, with differences between groups determined using log rank analysis, and statistical significance obtained using X2 tests. RESULTS: Primary patency for wrist fistulae was 49, 41 and 32% at 6, 12 and 24 months, respectively, and 57, 51 and 38% for elbow fistulae. Regression analysis showed fistula survival to be significantly greater in males than in females (p=0.023). Fistula survival rates in non-diabetics patients were higher than in patients with diabetes however, this was not significant (p=0.11); (54, 48 and 34% in diabetics compared to 45, 35 and 26% in non-diabetics at 6, 12 and 24 months, respectively). Age did not influence fistula survival; however, it did affect patient survival. Patient survival was 90, 74 and 56% at 1, 2 and 3 yrs, respectively, and in >60s fell to 86, 71 and 50%. Overall 74/245 (30%) patients died. CONCLUSION: These results suggest that overall primary patency rates for wrist and elbow fistulae are comparable to similar studies at 6, 12 and 24 months. Fistula survival after this period is dictated by poor patient survival. Our findings suggest that creation of primary vascular access at the elbow in older females and diabetics may be associated with better results.

Anatomical flow phantoms of the nonplanar carotid bifurcation, part I: computer-aided design and fabrication.

Doppler ultrasound is widely used in the diagnosis and monitoring of arterial disease. Current clinical measurement systems make use of continuous and pulsed ultrasound to measure blood flow velocity; however, the uncertainty associated with these measurements is great, which has serious implications for the screening of patients for treatment. Because local blood flow dynamics depend to a great extent on the geometry of the affected vessels, there is a need to develop anatomically accurate arterial flow phantoms with which to assess the accuracy of Doppler blood flow measurements made in diseased vessels. In this paper, we describe the computer-aided design and manufacturing (CAD-CAM) techniques that we used to fabricate anatomical flow phantoms based on images acquired by time-of-flight magnetic resonance imaging (TOF-MRI). Three-dimensional CAD models of the carotid bifurcation were generated from data acquired from sequential MRI slice scans, from which solid master patterns were made by means of stereolithography. Thereafter, an investment casting procedure was used to fabricate identical flow phantoms for use in parallel experiments involving both laser and Doppler ultrasound measurement techniques.

Dual phenotypic expression of hepatocytes and bile ductular markers in developing and preneoplastic rat liver.

This study supports the existence of a pluripotent liver stem cell population which has the potential to differentiate into hepatocytes and bile ductular cells. We compared the expression of hepatocyte-specific and bile ductular-specific markers in fetal and preneoplastic rat liver. L-pyruvate kinase (L-PK) and alpha glutathione S-transferase (GST) were used as adult hepatocyte-specific markers, while cytokeratin 19 (CK19) was used as a bile ductular-specific marker. pi GST and M2-pyruvate kinase (M2-PK), which are fetal hepatocyte-specific and expressed at high levels in the oval and duct-like cells, were also used. We characterized fetal liver derived from 13-21 days of gestation (E13-E21). pi GST was detected in the E18 hepatoblasts, which form the intrahepatic bile ducts, while CK19 was detected at E19. Some of these cells express alpha GST and L-PK from E19 to E21. Oval, duct-like and bile ductular cells in rats treated with a choline-deficient diet containing 0.07% ethionine (CDE diet) for up to 8 weeks were characterized by double immunocytochemistry. L-PK and alpha GST are absent from bile ductular cells in the normal adult liver and up to 3 weeks of CDE treatment. After 4-5 weeks on CDE treatment, the majority of bile ductular cells express L-PK, while at 6 weeks some co-express L-PK and alpha GST. There are two populations of oval cells, a major population expressing only the fetal hepatocyte markers, while a minor population expresses the fetal hepatocyte, adult hepatocyte and bile ductular markers. There are at least three different duct-like cell populations which co-express different markers and have characteristics of fetal hepatocytes at sequential stages of differentiation. One population co-expresses pi GST and M2-PK and is similar to fetal hepatocytes derived from E13-E14 fetuses. The second expresses the two fetal markers and L-PK, and this reflects characteristics of E15 hepatocytes. The third expresses pi GST, M2-PK, L-PK and alpha GST which is characteristic of E16-E19 hepatocytes. Upon withdrawal of the CDE diet, autoradiography using tritiated thymidine shows that oval and duct-like cells differentiate into hepatocytes. This study demonstrates that oval and duct-like cells express both hepatocytic and bile ductular markers, and have the capacity to differentiate into hepatocytes, characteristics similar to hepatoblasts in the developing rat liver.

Lupus anticoagulant in patients with peripheral vascular disease: a prospective study.

OBJECTIVE: To assess the incidence of lupus anticoagulant (LAC) in patients with peripheral vascular disease. DESIGN: Prospective clinical study. SETTING: University Hospital. MATERIALS: 20 patients with claudication (group 2), 20 patients with critical ischaemia (group 3) and 20 patients prior to elective abdominal aortic aneurysm surgery (group 4) were compared to 20 general surgical controls (group 1). CHIEF OUTCOME MEASURES: Venous blood samples for coagulation assay. MAIN RESULTS: Positive results for LAC by the Dilute Russell's viper venom time (DRVVT) with the platelet neutralisation procedure were present in 26 out of 60 vascular patients compared with none of the 20 general surgical controls. The three vascular groups showed a similar prevalence of LAC and this differed significantly from that in the control group (chi 2 = 10.94, p = 0.0009). Of the 26 positive results only three were associated with an abnormal activated partial thromboplastin time (APTT), which has previously been used as a marker for the presence of LAC activity. Fibrinogen levels were raised in seven of 20 patients in group 2 but were normal in the remaining vascular groups (p = 0.001). The mean factor VII level (124.1 units dl-1) in group 2 was higher than the mean of the remaining vascular patients (109.3 units dl-1, p < 0.05). CONCLUSIONS: The high prevalence of LAC in patients with peripheral vascular disease and the associated increased risk of early graft thrombosis may justify routine testing by DRVVT prior to reconstructive vascular surgery. Treatment of these patients with antiplatelet agents or formal anticoagulation perioperatively should be considered.

Differentiation of oval cells into duct-like cells in preneoplastic liver of rats placed on a choline-deficient diet supplemented with ethionine.

Feeding male Wistar rats a choline-deficient diet containing 0.07% DL-ethionine (CDE diet) for up to 5 weeks results in the production of two distinct non-parenchymal cell populations, oval and duct-like cells. These cells can undergo replication and display different patterns of expression of glutathione S-transferases (GSTs) and pyruvate kinases (PKs). Oval cells were first detected around the periportal region after 1 week of CDE treatment and infiltrated the parenchyma after 2 weeks. Duct-like structures first appeared as isolated ducts in the parenchymal region at 2 weeks and were easily detected after 2.5 weeks. These duct-like structures differed from the bile ducts which reside in the portal region. Large concentrations of duct-like structures in cyst-like clusters were detected after 5 weeks. Enlargement of these structures from single ducts to clusters of up to 20 ducts was observed over 3-5 weeks of CDE treatment. The number of cells forming a duct increased from 5 to 30 cells. We established a double immunocytochemical staining technique to characterize the oval and duct-like cells for their expression of GSTs and PKs. pi GST and M2-PK, which are fetal hepatocytes isoenzymes, are present in virtually all the oval and duct-like cells. Most of the oval cells are devoid of the adult hepatocytes markers, alpha GST, mu GST and L-PK. There are two sub-populations of duct-like cells, one which expresses only fetal markers and the other which co-expresses the adult and fetal isoenzymes. Hence, oval cells display characteristics of fetal hepatocytes and some duct-like cells appear more mature than oval cells. Using a combination of double immunocytochemical and [3H]thymidine labelling techniques we have established that oval cells differentiate into duct-like cells.

Immediate post partum thrombosis of the veins of the round ligament imitating an irreducible inguinal hernia.

Following delivery, our patient presented acutely with a painful swelling in the groin. Diagnosis could only be established by exploration. Thrombosed veins of the round ligament were found on histology of the swelling. Exploration was necessary to rule out an acute inguinal hernia.

Intravenous digital subtraction angiography versus computed tomography in the assessment of abdominal aortic aneurysm.

Results of preoperative investigation of 127 patients who underwent elective aortic aneurysm repair during a 3-year period were examined and compared with findings at operation. The accuracy of preoperative computed tomography (CT) and intravenous digital subtraction angiography (DSA) in assessing proximal and distal aneurysm extent was compared. From a total of 118 CT scans, ten of 12 suprarenal aneurysms were correctly predicted, with 11 false positives (positive predictive value 48 per cent, sensitivity 83 per cent, specificity 90 per cent). After 103 DSA investigations, six of ten suprarenal aneurysms were correctly predicted with one false positive (positive predictive value 86 per cent, sensitivity 60 per cent, specificity 99 per cent). Using CT, 30 of 54 aneurysmal iliac arteries were correctly diagnosed with 20 false positives (positive predictive value 60 per cent, sensitivity 56 per cent, specificity 88 per cent). Thirty-six of 48 aneurysmal iliac arteries were diagnosed correctly using DSA, with 32 false positives (positive predictive value 53 per cent, sensitivity 75 per cent, specificity 79 per cent). Intravenous DSA also provided useful information about renal and peripheral occlusive disease. Both investigations have their own specific limitations; clinicians should be aware of these when ordering and interpreting them.

Comparison of three methods for measuring cigarette smoking in patients with vascular disease.

Although smoking has been identified as an independent risk factor in peripheral vascular disease, smokers do not accurately report their habit. Therefore, a cheap, non-invasive, objective method of measuring smoking behaviour in vascular surgical units is desirable. The value of end-expiratory carbon monoxide monitoring, which is both simple and inexpensive, was compared with two well-established, validated techniques (serum thiocyanate and blood carboxyhaemoglobin levels). Some 33 surgical patients with peripheral vascular disease provided samples of expired air for measurement of carbon monoxide and blood for carboxyhaemoglobin and thiocyanate levels. Carboxyhaemoglobin was the most sensitive test (90%) and had a high specificity (100%). Expired carbon monoxide was the least sensitive (60%) but had a high specificity (100%). The carbon monoxide and carboxyhaemoglobin levels correlated significantly (r = 0.829; P = 0.0001). Serum thiocyanate was relatively sensitive (80%) but had a lower specificity (70%). Conventional methods for assessing smoking behaviour have not gained widespread use because they are time-consuming, relatively invasive and require technical support. Non-invasive measurement of carbon monoxide gives immediate accurate results and is a useful inexpensive method for measuring cigarette smoking in patients attending a follow-up vascular unit.

Postural changes in femoral artery blood flow in normal subjects, patients with peripheral vascular occlusive disease and patients undergoing lumbar sympathectomy, measured by duplex ultrasound flowmetry.

Regulatory peripheral vasoconstriction occurs in response to lower limb dependency. In mildly ischaemic limbs these responses are retained but are lost in patients with rest pain. Previously used methods have inherent difficulties when applied during postural change. We studied orthostatic responses in 12 normal subjects (aged 22-74 years, median 52 years) and 16 patients (aged 21-83 years, median 48 years) with mild and severe peripheral vascular disease using a duplex ultrasound flowmeter. In the normal subjects the 60-s mean common femoral artery volume flow values (ml min-1 +/- S.D.) were 77 +/- 83; -78 +/- 116; -190 +/- 136 for elevation, dependency and standing respectively. For claudicants (n = 7) the values were 18 +/- 37; -112 +/- 123; -216 +/- 103, respectively. In rest pain patients (n = 9) the responses were reversed, being -252 +/- 124; 131 +/- 89 and 184 +/- 85. Significant differences were apparent between elevation, dependency and standing flows, in each of the three groups (all p less than 0.0001). The rest pain group displayed characteristically different responses compared with both normal subjects and claudicants, for each postural change (p less than 0.0001 in all cases). Investigation of the dependency response was undertaken in eight further patients with rest pain before and after lumbar chemical sympathectomy and a characteristic pre-sympathectomy response predicted the clinical outcome.

Day case laparoscopy: a survey of postoperative pain and an assessment of the value of diclofenac.

A randomised, controlled study was undertaken to assess the postoperative pain and side effects experienced by patients undergoing day case diagnostic laparoscopy and laparoscopic sterilisation, and to evaluate the effectiveness in these patients of peroperative diclofenac. Patients undergoing laparoscopic sterilisation had significantly higher pain scores at one hour postoperatively, and at discharge, than patients undergoing diagnostic laparoscopy (p less than 0.01) but there were no significant differences in pain scores 24 hours after discharge. The incidence of postoperative side effects following discharge from hospital was high, but there were no significant differences between the groups. Diclofenac had no significant effect in either group on the severity of postoperative pain, or the incidence of postoperative side effects.

Effect of postural change on common femoral artery volume flow, measured by duplex ultrasound, in normal subjects and patients with peripheral vascular disease.

Regulatory peripheral vasoconstriction occurs in response to adoption of the erect posture. Mildly ischaemic limbs are thought to exhibit near normal responses, but patients with rest pain show increases in blood flow on limb dependency. Previous methods of limb blood flow quantification (xenon clearance and venous occlusion plethysmography) have inherent difficulties when applied in these situations. We studied orthostatic responses in 12 normal subjects (aged 22-74 years (median 52) and 16 patients (aged 21-83 (median 48) with mild and severe peripheral vascular disease, using a duplex flowmeter system. In the normal subjects changes in the 60s mean, common femoral artery volume flow values were as follows (ml min-1 (1 SD]: 77 (83), -78 (116) and -190 (136), for elevation, dependency, and standing respectively. For claudicants (n = 7) the values were 18 (37), -112 (123) and -216 (103) respectively. In rest pain patients (n = 9) the responses were reversed, being -252 (124), 131 (89) and 184 (85) respectively. Significant differences were apparent between elevation, dependency and standing flows in each of the three groups (P less than 0.0001). Normal subject and claudicant responses on elevation and dependency differed significantly (P less than 0.0001 and 0.03 respectively). On standing, the responses were similarly significantly different. The rest pain group displayed characteristically different responses compared with both normal subjects and claudicants for each postural change (P less than 0.0001 in all cases). Duplex ultrasound volume flowmetry is non-invasive and offers an excellent method of quantifying physiological changes.

Common femoral artery volume flow in peripheral vascular disease.

Common femoral artery volume flow was measured at rest and during postocclusive reactive hyperaemia in 80 normal subjects and 67 patients with radiological evidence of occlusive peripheral vascular disease. At rest, means(s.d.) common femoral artery volume flow in normal subjects (344(135) ml/min) and all patients with peripheral vascular disease (401(168) ml/min) was not significantly different. During postocclusive reactive hyperaemia, mean(s.d.) peak flow was significantly higher in normal subjects (1951(438) ml/min) than in patients with peripheral vascular disease (996(457) ml/min) (P less than 0.01). Common femoral artery volume flow in patients with critical ischaemia and intermittent claudication did not differ at rest but mean(s.d.) peak flow in patients with critical ischaemia (697(276) ml/min) was significantly lower than in claudicants (1131(447) ml/min) (P less than 0.01). Mean(s.d.) resting common femoral artery volume flow in limbs with femoropopliteal disease (457(185) ml/min) was significantly greater than that in limbs with occlusion of the aortoiliac segment (308(130) ml/min) (P less than 0.01). However, this difference did not persist during postocclusive reactive hyperaemia. A hyperaemic index, calculated from the hyperaemic responses to below knee and whole limb ischaemia, was used to quantify segmental perfusion during postocclusive reactive hyperaemia. The mean(s.d.) value in normal subjects, 46(9) per cent, and in those with aortoiliac disease, 52(12) per cent, indicated approximately equal perfusion of the above and below knee limb segments. In those with femoropopliteal disease the mean(s.d.) hyperaemic index was 17(13) per cent, revealing relative hypoperfusion of the below knee segment.

Nifedipine in patients with peripheral vascular disease.

The calcium antagonist nifedipine has been studied in a group of patients with intermittent claudication. In a long-term double blind, placebo controlled trial in 27 patients there was no effect on exercise tolerance as measured by pedal ergometry and only a limited improvement in symptom score on double dose nifedipine. Common femoral artery volumetric blood flow (measured by duplex ultrasound) was unaffected. The acute effects on blood flow were also studied, with a mean increase of 23% in common femoral artery blood flow 30 min after sublingual nifedipine. The administration of nifedipine to patients with peripheral vascular disease will not adversely affect claudication symptoms, and may result in an acute improvement in lower limb blood flow. Nifedipine is a suitable antihypertensive in patients who suffer from intermittent claudication.

Use of myocutaneous flaps for primary cover following lymph node dissection for malignant melanoma.

We report seven patients undergoing palliative surgery for advanced malignant melanoma, who required wide excision of skin and underlying tissue in association with lymph node dissection. In each case, primary closure of the wound was facilitated by the use of a myocutaneous flap. Four ilio-inguinal lymph node dissections were closed with rectus abdominis flaps, two cervical dissections were closed with a pectoralis major flap, and a limited latissimus dorsi flap was used for one axillary clearance. Primary healing was achieved in all cases; morbidity was low, with one wound infection and two limited lymphatic collections. All donor sites were closed primarily and healed well. We conclude that in selected patients the use of a myocutaneous flap procedure gives excellent coverage of large defects with low morbidity. In particular, there is rapid convalescence and return of good function after palliative resections, while the wide excision minimizes local recurrence where the tumour is in proximity to overlying skin.