Paget-Schroetter syndrome treated with cutting-balloon angioplasty.

Here, a case of Paget-Schroetter Syndrome in a 25-year-old guitar player is reported. After thrombolysis, conventional angioplasty failed to dilate the underlying subclavian stenosis both before and after first-rib excision with scalenus anterior and medius division. For the third attempt at angioplasty, a cutting balloon was used, which immediately produced a good result. Venography at 4-year follow-up showed no restenosis and no functional deficit. This case report demonstrates that cutting-balloon angioplasty may be considered when conventional balloon fails and may have greater durability than conventional balloon angioplasty in the treatment of Paget-Schroetter syndrome.

Effects of marine biofouling on gas sensor membrane materials.

The use of underwater gaseous sensors has increased rapidly in the last 10 years. The majority of such sensors employ a thin membrane through which the gas diffuses. These sensors are potentiometric gas-sensing probes and essentially they are ion-selective electrodes. The deployment time of these membranes is curtailed by the formation of biofouling on the membrane leading to erroneous results. The physical properties of a variety of commonly used membranes were investigated using SEM and AFM. This showed that there were differences in topography between the PTFE membranes, such as pore sizes and surface roughness, which may be attributed to the manner in which they are manufactured. The pore size of the PTFE membranes varied greatly, ranging from circular pores with a diameter of 500 nm to elongated pores measuring 1 x 22 microm. The contact angle of each membrane showed that they were all hydrophobic. The amount of fouling on each was also observed and its affect on oxygen diffusion was monitored. Fouling slowed down the response of the instrument and caused reduced diffusion through the membranes. The amount of fouling varied between the membranes with the YSI membrane fouling least. Some of the membranes tested did foul less than others and there could be lifetime advantages of choosing a membrane with a smoother surface and a small pore size.

The relationship between plasma MMP-1, -7, -8 and -13 levels and embolic potential during carotid endoluminal intervention.

BACKGROUND: Patients undergoing carotid endoluminal intervention are at risk of embolic stroke even with the use of distal protection devices. Matrix metalloproteinases (MMPs) have been implicated as a causal factor in plaque instability leading to spontaneous embolisation. We investigated whether plasma MMP levels correlated with the embolisation during carotid endoluminal intervention. METHODS: Thirty circumferentially intact carotid endarterectomy specimens were subjected to a standardised angioplasty procedure in a pulsatile ex vivo model. Emboli collected in a series of distal filters were counted and sized. Plasma samples were collected pre-operatively and analysed for MMP-7 and MMP-8 levels using Western immunoblotting. MMP-1 and MMP-13 levels were determined using ELISA. Emboli number and maximum size were correlated with plasma levels of the MMPs using Spearmans rank. RESULTS: Total MMP-8 levels were related to maximum embolus size (r=0.442, p=0.005) but not emboli number (r=0.342, p=0.052). MMP-1, -7 and -13 were not correlated with either emboli number or with maximum embolus size. CONCLUSION: Pre-operative plasma MMP-8 levels are related to the size of emboli from plaques during carotid endovascular intervention. Further in vivo studies need to be performed to assess the importance of this finding. There is potential for development of plasma markers to identify those patients at greater risk of embolic stroke during carotid endoluminal intervention.

Carotid angioplasty in a pulsatile flow model: factors affecting embolic potential.

OBJECTIVES: Carotid endoluminal intervention is an alternative to surgery but carries a risk of embolic stroke even with distal protection devices. We investigated the clinical features and degree of stenosis related to number and size of emboli during carotid angioplasty. DESIGN: An experimental ex vivo study. MATERIALS: An ex vivo pulsatile flow model was used in which temperature, velocity, flow, pressure and viscosity characteristics were designed to simulate the carotid circulation. METHODS: Carotid endarterectomy specimens excised as intact cylinders (n = 28) were subjected to a standardised angioplasty procedure using radiological guidance. Emboli collected in filters placed distally were counted and sized using microscopy. RESULTS: Median number of emboli during angioplasty was 133 (range 15-1331). Median size of the largest embolus was 700 microns (range 75-2400). Severity of stenosis correlated with increased maximum size (r = 0.55, p = 0.012). Statin therapy >4 weeks pre-operatively was associated with reduced emboli number and size (54 (range 15-748) vs 247 (range 37-1331) [p = 0.023] and 400 microm (range 75-2400) vs 1300 microm (range 600-2200) [p = 0.022]). CONCLUSIONS: In this model a wide range of emboli number and size were produced. Number and size of embolic particles were highest in patients with high-grade stenoses not receiving statin therapy.

Release studies of benzalkonium chloride from hydrogel in a freshwater environment.

The use of underwater optical sensors to monitor pollution and climate change processes has led to the development of robust instruments able to be deployed in lakes and seas for months at a time. However, despite this improvement in their durability they are subject to biofouling on their optical ports resulting in erroneous readings. The use of hydrogel coatings containing the cationic surfactant benzalkonium chloride (BAC) has been shown to prevent the development of biofouling for up to 12 weeks in the marine environment. In this study the use of hydrogel coatings in the freshwater environment was less successful with fouling visible at 2 weeks. In both field and laboratory studies a rapid initial loss of BAC from the hydrogel film was observed. The loss is a combination of diffusive and mass flow but the period from 12 to 50 h appeared to fit to diffusion kinetics and a diffusion coefficient of 7.3 x 10(-8) cm2 s(-1) (13 degrees C) was calculated, an order of 10 times greater than that found in seawater. Subsequently the rate of loss of the residual BAC, for which a diffusion coefficient of 5.7 x 10(-10) cm2 s(-1) (15 degrees C) was measured, was too low to prevent the early stages of biofouling.

The benefit of STent placement and blood pressure and lipid-lowering for the prevention of progression of renal dysfunction caused by Atherosclerotic ostial stenosis of the Renal artery. The STAR-study: rationale and study design.

BACKGROUND: Atherosclerotic renal artery stenosis (ARAS) is associated with progressive loss of renal function and is one of the most important causes of renal failure in the elderly. Current treatment includes restoration of the renal arterial lumen by endovascular stent placement. However, this treatment only affects damage caused by ARAS due to the stenosis and ensuing post-stenotic ischemia. ARAS patients have severe general vascular disease. Atherosclerosis and hypertension can also damage the kidney parenchyma causing renal failure. Medical treatment focuses on the latter. Lipid-lowering drugs (statins) could reduce renal failure progression and could reduce the overall high cardiovascular risk. The additional effect on preserving renal function of stent placement as compared to medical therapy alone is unknown. Therefore, the STAR-study aims to compare the effects of renal artery stent placement together with medication vs. medication alone on renal function in ARAS patients. METHOD: Patients with an ARAS of > or = 50% and renal failure (creatinine (Cr) clearance < 80 mL/min/1.73 m2) are randomly assigned to stent placement with medication or to medication alone. Medication consists of statins, anti-hypertensive drugs and antiplatelet therapy. Patients are followed for 2 yrs with extended follow-up to 5 yrs. The primary outcome of this study is a reduction in Cr clearance > 20% compared to baseline. This trial will include 140 patients.

Method for the measurement of the diffusion coefficient of benzalkonium chloride.

Biofilm formation on the optical ports of cameras and underwater sensors is the primary cause of their reduced useful deployment time. The use of a transparent hydrogel coating containing the cationic surfactant benzalkonium chloride has been shown to extend the deployment times for up to 12 weeks for these instruments. In order to predict the effective lifetime of these coatings it was necessary to obtain the diffusion coefficient of the benzalkonium chloride used in the coatings. Benzalkonium chloride can have different alkyl chain lengths ranging from C8H17 to C18H37 with chain length greatly affecting its chemical properties. The benzalkonium chloride materials investigated here were mixtures of C12H25 and C14H29 as well as C14H29 on its own. These materials were selected for their proven biofilm resistant qualities. The diaphragm diffusion cell technique was investigated for its applicability to the measurement of diffusion coefficients of molecules with surfactant properties and the ability to form micelles. The method was found to be satisfactory for the cationic surfactant benzalkonium chloride. The average value of the membrane cell integral diffusion coefficient D was 7.78 x 10(-6) cm2 s(-1) at 25 degrees C and there was no significant effect of alkyl chain length on the measured value of D.

Internal stenting in malignant biliary obstruction.

Internal stenting in inoperable malignant biliary obstruction plays an important role in patient management. Surgical bypass may still be undertaken where there is also duodenal obstruction, though the need for gastroenterostomy may be reduced with the increasing use of metallic stents for the relief of malignant gastric outlet obstruction. Stents may be placed endoscopically or percutaneously, though in most centers the endoscopic route is usually tried first, with the percutaneous route being reserved for endoscopic failures. Plastic and self-expanding metallic biliary stents are available, each with its own advantages and disadvantages. In general, longer periods of patency are observed with metallic stents, though they are more expensive. Plastic stents can be changed endoscopically relatively easily when they have blocked, and in practice it is common for plastic stents to be inserted via this route for initial biliary drainage. If there is prolonged survival thereafter, many workers insert a metallic stent in an attempt to reduce the number of interventions required. If the percutaneous route is being employed, the histologic diagnosis has been confirmed, and the malignancy is inoperable, our practice is to use a self-expanding metallic stent, as the delivery system is relatively small and subsequent occlusion less likely.

Epirubicin, cisplatin, and prolonged or brief infusional 5-fluorouracil in the treatment of carcinoma of unknown primary site.

The cytotoxic regimen of epirubicin, cisplatin, and continuous infusional 5-fluorouracil (ECF) has demonstrated activity in a range of malignancies, including gastroesophageal, breast, and pancreatic cancers. Prolonged infusional central venous catheter (CVC) mediated therapy is not always feasible and modifications of the 5-fluorouracil (5FU) schedule have been reported. We reviewed our experience of both the standard and a modified ECF regimen in patients diagnosed with carcinoma of unknown primary site (CUPS). A retrospective analysis of all patients diagnosed with CUPS (31 adenocarcinoma and 5 poorly differentiated carcinoma) and treated with ECF between June 1994 and June 1998 was undertaken. Thirty-six patients, median age 56 (range: 24-74), were treated thrice-weekly with 50 mg/m2 epirubicin, 60 mg/m2 cisplatin, and 5-FU administered either by continuous infusion 200 mg/m2/d via a CVC (standard ECF) or as a 6-h infusion 600 mg/m2 through a peripheral venous catheter (modified ECF). Thirteen patients were treated with standard ECF and 23 received modified ECF. The median number of cycles administered was 4 (range: 1-10). Thirty-two patients had evaluable disease, seven (22%; 95% confidence interval: 8-36%) demonstrated a partial response, including three patients that received standard ECF and four treated with modified ECF. There were no complete responses. The median survival for all 36 patients was 9.0 mo. Median survival for patients treated with standard ECF was 11.7 mo as compared to 5.1 mo for the modified ECF schedule (p = 0.052). Liver involvement and elevation of serum CA19.9 were identified as possible adverse prognostic factors. Both regimens were well tolerated, with the only grade 3/4 toxicity recorded being leukopenia (four patients), nausea/vomiting (seven patients), and diarrhea (one patient). CVC complications in the standard ECF group were thrombosis (one patient) and infection (three patients). There were no treatment-related deaths. We conclude that ECF, whether modified or standard, has modest activity in the setting of CUPS. Patient survival is comparable to survival documented in previous reports of CUPS treatment. The apparent survival difference between the two ECF schedules may be the result of patient selection factors. The optimal treatment of CUPS remains unknown and can only be determined through randomized controlled trials.

An alternative approach to antifouling based on analogues of natural processes.

A number of marine organisms are able to resist fouling pressure and remain essentially free of fouling. Some organisms are totally devoid of even the first stages of biofilm formation involving bacteria and microalgae. A key feature in recent research has been the realisation that previous low adherence technology is an insufficient technical solution and that natural models, based on marine and other organisms, incorporate other passive techniques for fouling resistance. These characteristics may be incorporated into physical analogues of the natural processes. This paper describes ways of producing physical analogues of some such characteristics, the application of such techniques to surfaces in the marine environment and the environmental impact. The paper includes some results of recent trials and a cost comparison.

Stenting in the oesophagus.

Self-expanding metallic stents have assumed increasing importance in the palliative treatment of malignant dysphagia in recent years. This is most commonly the result of inoperable oesophageal cancer, but may also be the result of extrinsic compression on the oesophagus by other malignant masses. Stents are also occasionally used as a last resort in benign disease.

Self-expanding metallic stents in the management of pyloric dysfunction after gastric pull-up operations.

The purpose of this paper is to report the use and benefits of self-expanding metallic stents employed in pyloric dysfunction. Four patients treated with oesophagectomy and gastric pull-up for oesophageal carcinoma failed to respond to balloon dilatation for pyloric dysfunction. Three of the patients were thought to have residual tumour at sites remote from the pylorus prior to stenting, but the fourth, who had undergone surgery 8 years previously, was thought to be cured. All were treated with self-expanding metallic stents. All four patients responded well with resolution of their symptoms. Over a mean follow-up of 6 months there has been no recurrence of symptoms. Stent insertion represents a potentially valuable method of treatment in patients with post-surgical pyloric dysfunction in whom simple balloon dilatation has failed.

Radiological management of oesophageal strictures.

Interventional radiologists have an increasing role in managing oesophageal strictures. Fluoroscopically-guided balloon dilatation can relieve dysphagia in patients with benign strictures in about 95% of cases with minimal associated complications. Over 95% of patients with inoperable malignant oesophageal strictures can be successfully palliated with self-expanding metallic stents.

Management of malignant oesophageal obstruction with self-expanding metallic stents.

BACKGROUND: The use of self-expanding metal stents for palliation of malignant dysphagia is increasing. Experience in 70 patients was reviewed with respect to the value of stenting and management of the complications encountered. METHODS: Oesophageal stents were inserted in 70 patients (42 men) of mean age 73 years with malignant oesophageal obstruction. Data regarding stent insertion and degree of dysphagia were gathered prospectively. RESULTS: Seventy-six stents were placed in 70 patients. By the end of the study 57 patients had died and 13 were still alive. Three patients died within 3 days of stent insertion and dysphagia was relieved in 64 of the 67 patients remaining. Stent migration, tumour ingrowth and overgrowth, and food impaction were encountered during follow-up in eight patients. CONCLUSION: Insertion of self-expanding metal stents for the palliation of malignant oesophageal obstruction is a successful therapy which can be carried out with relative ease. Palliation of dysphagia with an appropriate stent can be expected in up to 95 per cent of patients.