Clinical thromboembolic detterrent stockings application: are thromboembolic detterrent stockings in practice matching manufacturers application guidelines.

BACKGROUND: Thromboembolic detterrent (TED) stockings have been shown to be effective in the reduction of thromboembolic events in post operative patients. These manufactured stockings create graduated compression from ankle to calf. AIM: To assess whether the manufacturers' recommendations for application were being met in a District general hospital setting and whether this achieved the desired gradient of compression. METHODS: We carried out pressure measurements on 100 legs in post-operative patients and recorded reasons for poorly fitting stockings. Pressure measurements were taken at standard positions around calf and ankle using a pre-calibrated subbandage pressure measuring device. RESULTS: About 20% of stockings were worn incorrectly by patients. Median pressure applied at the ankle was 13 mmHg (range, 6.5-18.5) compared to the manufacturers' intended compression of 18 mmHg. Only 14% of the stockings showed an acceptable gradation of reduced pressure between ankle and calf. About 23% of the stockings exerted a positive pressure at calf level compared to the ankle. CONCLUSION: Most TED stockings do not produce a standardised Siegel profile pressure gradient decrease from ankle to calf. This may be due in part to fluid changes after surgery in combination with the large variation in size of lower limbs. Our District general hospital utilises three of the six sizes of TED stocking, and remeasurement was not taking place every 24 h as per guidance. This as the result show not only negates the benefit of TED stockings but may also exert harm in terms of venous thromboembolism risk. This finding adds further weight to the argument of whether TED stockings may not be having the desired prophylactic effect and may even be resulting in harm in select cases.

Late complications after ligation and bypass for popliteal aneurysm.

BACKGROUND: Ligation and bypass is standard treatment for popliteal aneurysm. This technique does not abolish collateral circulation to the aneurysm, which may continue to expand and/or rupture. This study assessed whether complete thrombosis of the aneurysm sac occurs after operation and examined the long-term clinical outcome. METHODS: The records of all patients who underwent popliteal aneurysm repair in a university hospital over 10 years were reviewed. Patients who had undergone ligation and bypass were recalled for clinical and ultrasonographic examination to determine the fate of the aneurysm sac. RESULTS: Persistent blood flow in the aneurysm sac was present in 12 of 36 legs a median of 48 months after operation. This was associated with symptomatic enlargement of the aneurysm in six patients. The incidence of sac enlargement was lower in bypassed aneurysms with no intrasac flow on duplex examination. CONCLUSION: Ligation and bypass does not always abolish blood flow in the sac of a popliteal aneurysm. It may be associated with continued expansion and late complications.

The distaflo graft: a valid alternative to interposition vein?

INTRODUCTION: the rationale behind the Distaflo graft is inhibition of myointimal hyperplasia through optimisation of haemodynamic forces at the distal anastomosis. This prospective study reports our early clinical results. METHOD: patients with critical limb ischaemia, but no autologous vein, underwent infrainguinal bypass using Distaflo. Clinical and Duplex assessment provided prospective data from which one year cumulative patency, limb salvage and survival rates were calculated using Kaplan-Meier analysis. Log rank test enabled comparison with an historical control group of Miller cuff grafts. RESULTS: fifty Distaflo were inserted over 29 months into 46 patients, median age 68.5 years, 27 male (59%), of which 27 (54%) were re-do procedures. Proximal anastomoses were to common femoral arteries in 40 cases (80%); distal anastomoses were to popliteal vessels in 20 (40%), and tibial vessels in 30 (60%). The Distaflo graft had patency, limb salvage and survival rates of 39, 50 and 82% respectively compared to 49, 56 and 85% respectively in the control group, with no statistical difference (p = 0.39; 0.65; 0.67 respectively; log rank). CONCLUSION: in this non-randomised study, the Distaflo has similar one year patency, limb salvage and survival rates to the Miller cuff, potentially justifying its use an alternative in distal prosthetic arterial reconstruction for critical limb ischaemia.

Changes in endothelial, leucocyte and platelet markers following contrast medium injection during angiography in patients with peripheral artery disease.

Peripheral artery angiography, a common diagnostic procedure, may cause early and late adverse reactions, such as anaphylaxis, thrombosis and possible progression of the underlying arterial disease. To test the hypothesis that radiographic contrast medium may contribute to these events by adversely affecting the endothelium, leucocytes and/or platelets, 19 subjects undergoing angiography for the investigation and/or treatment of lower limb atherosclerosis were recruited. Blood was obtained from the external iliac vein before, and at serial intervals after, the injection of radiographic contrast medium into the ipsilateral femoral artery for diagnostic use. Markers of endothelial cell injury (von Willebrand factor (vWf)), platelet activation (soluble P-selectin) and leucocyte activation (neutrophil elastase and soluble L-selectin) were measured in citrated plasma. Soluble intercellular adhesion molecule-1 (sICAM-1) and thromboxane B(2), which are non-specific markers of inflammation, were also measured. Compared with the sample prior to angiography, levels of soluble L-selectin and sICAM-1 were reduced (p<0.02) immediately after passage of the last bolus of contrast medium. 15 min later, levels returned to normal but the level of vWf had increased (p<0.02). After 30 min, only levels of thromboxane B(2) were increased (p<0.05). The following day both vWf (p<0.01) and soluble P-selectin (p<0.05) were increased. These data point to both early and late effects of contrast medium on markers of endothelial, platelet and leucocyte function.

Large bowel impaction by the BioEnterics Intragastric Balloon (BIB) necessitating surgical intervention.

A case of large bowel impaction caused by migration of a BioEnterics Intragastric Balloon (BIB) is presented. The literature is reviewed regarding both the use and the complications inherent in such balloon devices. This is the first reported case of an intragastric balloon impacted in the colon 9 months after insertion.

Soluble adhesion molecules in clinical ischaemic injury.

BACKGROUND: Neutrophil adhesion is a prerequisite for ischaemic injury. In vitro research has shown that soluble adhesion molecules have an inhibitory effect on neutrophil binding AIMS: To determine whether the circulating forms of adhesion molecules are consumed during skeletal muscle ischaemic injury in man. METHODS: The response of the circulating forms of adhesion molecules ICAM-1 (intercellular adhesion molecule-1) and L-selectin to ischaemia and reperfusion was investigated in 23 patients during surgery involving aortic cross-clamping and in 20 volunteers with tourniquet-induced forearm ischaemia. RESULTS: In the aortic model the levels of circulating ICAM-1 fell from an initial value of 250 +/- 20 to 210 +/- 13 ng/ml (p < 0.05) and soluble L-selectin fell from 642 +/- 62 to 487 +/- 49 ng/ml during ischaemia (p < 0.05). There was a similar pattern of reduced levels of circulating adhesion molecules in the model of forearm ischaemia. However the recovery of these molecules during the reperfusion period differed between the two models. CONCLUSIONS: Soluble L-selectin and soluble ICAM-1 appear to be utilised during clinical models of ischaemia. This supports previous in vitro studies suggesting a role in competitive inhibition and these circulating molecules may be clinically important inhibitors of leukocyte adhesion.

Neutrophil activation and severity of tissue hypoxia during tourniquet-induced forearm ischemia in man.

Neutrophil activation and adhesion to the endothelium are thought to be central in the inflammatory response to reperfusion after ischemia. This study explores whether the severity of tissue hypoxia can be related to a biochemical measure. Venous blood was sampled from 20 volunteers undergoing tourniquet-induced forearm ischemia for 10 min and subsequent reperfusion. Samples were analyzed for neutrophil count, neutrophil hydrogen peroxide generation measured by flow cytometry, plasma thromboxane (a marker of platelet activation), the endogenous antioxidant glutathione peroxidase, and thrombomodulin, a marker of endothelial cell damage. Forearm oxygen saturation by near-infrared spectroscopy was monitored throughout the experiment. Neutrophil hydrogen peroxide generation fell from an initial mean fluorescent intensity (MFI) of 0.91 +/- 0.07 to 0.77 +/- 0.09 (mean +/- SE) during ischemia (P < 0.05) and this reduction correlated with severity of hypoxia (r = 0.56, P < 0.01). Plasma levels of glutathione peroxidase were also reduced during ischemia (P < 0.05) whereas plasma thromboxane levels rose (P < 0.05). There were no significant changes in plasma levels of thrombomodulin or circulating neutrophil count. In conclusion, alterations in a measurement of neutrophil function reflect the changes in tissue oxygenation and may act as a biochemical predictor of the severity of an ischemic injury.

The influence of acute smoking on leucocytes, platelets and the endothelium.

Cigarette smoking is a risk factor for the development of atherosclerosis. Possible mechanisms for this include leucocytes and platelet activation, and/or damage to the endothelium, any of which may contribute to changes in thrombosis and haemostasis. We examined the acute effects of smoking on these systems by obtaining blood before, immediately after, and at 10 and 30 min after the rapid smoking of two cigarettes in sequence by 20 smokers. Blood samples taken at the same time points from ten non-smokers acted as control material. In the smokers there was a transient rise in leucocyte count and neutrophil activation, but von Willebrand factor (VWF--marking endothelial damage) increased steadily at each time point (P <0.05). There were no changes in neutrophil elastase, soluble intercellular adhesion molecule-1 (sICAM-1 normally increased in smokers), fibrinogen, platelet count or soluble P-selectin (marking platelet activation, also normally increased in smokers). We conclude that the acute smoking of two cigarettes in succession will activate leucocytes and cause endothelial cell damage, but will not immediately influence platelet activity.

Rheological properties and function of blood cells in stored bank blood and salvaged blood.

The technique involving filtration of diluted blood enables the separate analysis of the flow properties of different cell subpopulations. This study was designed to assess the changes occurring in the flow properties and function of blood cells in stored bank blood and salvaged blood compared to patient blood in a given clinical situation. We measured hydrogen peroxide production by neutrophils and the filterability, through 5 microm Nucleopore filters, of isolated red blood cells and of diluted blood. Samples were obtained from patients undergoing aortic surgery and blood intended for transfusion: either salvaged during surgery or stored bank blood. Both salvaged and bank blood were much less filterable than patient blood, with reduced deformability of both red and white blood cells. However, salvaged blood contained highly activated neutrophils with a prolonged transit time of the 'fast-flowing' cells in the analysis compared to bank blood. Bank blood contained significantly more particles which acted as pore-blockers. Cells in bank and salvaged blood therefore have markedly abnormal flow and biochemical properties compared to patient blood.

A UK-wide trial of the Banff classification of renal transplant pathology in routine diagnostic practice.

BACKGROUND: The Banff classification of renal transplant pathology has gained wide support since its introduction in 1993. There have been several studies which have tested its usefulness in the context of research-oriented centres. We sought to evaluate its use in a wider context. METHODS: We recruited pathologists from all but one of the renal transplant centres in the UK. Sections were circulated from 21 selected, 'difficult' cases, in all of which the clinical question was confirmation or exclusion of acute rejection, and in all of which a definite diagnosis had been obvious from the subsequent clinical course. Participants were asked first to diagnose or exclude acute rejection by their usual approach, then to apply the Banff classification. No clinical information was given beyond the time since engraftment, in order to confine the evaluation to the morphological features present in the sections. At the end of the study the subjective impressions of the participants were sought using a structured questionnaire. RESULTS: Using the Banff classification produced no detectable difference in the number of 'correct' diagnoses when compared with a conventional approach, irrespective of whether the 'correct' diagnosis is based on retrospective clinical information or on the consensus opinion of the pathologists involved, and irrespective of where in the Banff schema one applies a 'cut-off' for the diagnosis of acute rejection. However, the reproducibility of the diagnoses was improved. The results suggest that in the Banff classification the best 'cut-off' for the diagnosis of acute rejection is between Banff category 3 and category 4, although in this difficult area we found a large improvement in diagnostic accuracy if input of clinical information occurs. CONCLUSIONS: The improved reproducibility justifies the use of the Banff classification to harmonise approaches between centres, especially in research projects. While there are good reasons also to adopt it in routine diagnostic practice, further refinement is necessary before an improvement in the accuracy of diagnosis can be demonstrated.

Repeated exercise induces release of soluble P-selectin in patients with intermittent claudication.

Controversy exists as to whether exercise in patients with intermittent claudication causes a harmful biochemical effect associated with an ischaemia-reperfusion injury of skeletal muscle. We report on exercise-induced changes in neutrophil activation, soluble P-selectin and von Willebrand factor in 34 patients with intermittent claudication and 12 matched controls. Von Willebrand factor (vWF) showed a cyclical pattern of response to exercise in control subjects (rising from 103 +/- 8 to 119 +/- 7 U/dl); claudicants did not show this pattern but had higher levels of vWF throughout (p <0.03). There was no consistent pattern of response in neutrophil hydrogen peroxide production to exercise in either claudicants or control subjects. Soluble P-selectin levels increased after exercise, but this only reached statistical significance after repeated exercise in claudicants (rising from 320 +/- 28 to 357 +/- 28 ng/ml). This rise in soluble P-selectin after exercise may indicate progressive platelet activation which may contribute to the excess cardiovascular mortality that claudicants are prone to.

Effect of stress on calcium homeostasis in sheep.

The acute effect of stress on the plasma and cerebrospinal fluid (CSF) immunoreactive parathyroid hormone (PTH) response was studied in 6 merino sheep. Stress was exerted by weak periodical electric square waves (PESW). In addition, the effect of intravenous injection of adrenaline was studied. Under stress conditions (PESW or adrenaline injection), plasma PTH increased up to 30% and up to 50%, respectively. Weak periodical electric square waves of 3-4 mA decreased CSF PTH concentrations by up to 50%. The effect of adrenaline injection on the CSF PTH was not significant. Total calcium and magnesium in plasma and CSF did not change. Our results showed that the effect of stress on the CSF PTH is opposite to the effect on plasma PTH, and suggest that both, PESW and adrenaline, affected PTH in plasma and CSF by a Ca-independent mechanism.