Simon Ashley

Management of popliteal artery aneurysms.

Background:  Popliteal artery aneurysms (PAA) are the most common peripheral aneurysm and are recognized as ‘the silent killer of the leg circulation’. The timing and type of interventions used in their treatment is still controversial. This review examines the published data on the natural history, epidemiology, clinical presentation and management options available. The aim of this study is to try and reach a consensus with regards to the best management of PAA.

A RANDOMISED TRIAL OF DIFFERENT COMPRESSION DRESSINGS FOLLOWING VARICOSE VEIN SURGERY

Objective: TED antiembolism stockings, Panelast self-adhesive elasticated bandages and Medi Plus class II stockings are three different dressings commonly used to provide compression following surgery for varicose veins. The aim of this study was to determine which of the three dressings was most acceptable to patients. Design: Forty-two patients undergoing bilateral varicose vein surgery were randomised to receive a different dressing on each leg in order to determine if a particular type of dressing was superior in its ability to reduce postoperative pain and provide adequate comfort without reducing mobility. The dressings were worn for 1 week, during which daily pain scores were recorded for each leg followed by a simple questionnaire to determine comfort and mobility. Results: There was a significant reduction of mobility experienced by patients wearing Panelast bandages compared with the other two dressings (p<0.05). However, there were no significant differences between the dressings with regard to the degree of postoperative pain experienced, and in all other respects the dressings were equally tolerated. Conclusion: The choice of compression dressings used for varicose vein surgery should depend primarily on the personal preference of surgeons as well as financial considerations.

The histological measurement of laser-induced thermal damage in vascular tissue using the stain picrosirius red F3BA

A histological technique for the measurement of laser-induced thermal tissue damage is described using the stain picrosirius red F3BA. This stain enhances the birefringence of normal collagen when viewed in polarized light. Areas of (thermally) denatured collagen, however, have no optical activity and can be measured directly by optical micrometry. The technique has been applied to experimental studies on both laser angioplasty and laser vascular anastomosis.The tissue ablation characteristics of various 2.2 mm diameter rounded sapphire laser angioplasty probes were compared by lasing (at 1064 nm) segments of porcine aorta under blood in vitro. A marked difference was observed between probes from different manufacturers, the Surgical Laser Technologies probe producing significantly greater forward tissue ablation with less associated lateral thermal damage.The relative degree of thermal damage caused by argon (488/514 nm) and Nd-YAG lasers during in vitro arteriotomy repair was also investigated. No difference was seen between the two wavelengths. However, the use of absorption-enhancing chromophore dyes as an aid to laser welding significantly reduced damage, particularly for the argon laser.In conclusion, we suggest that this histological technique is of considerable value in the investigation of the thermal effects of continuous-wave lasers.

High risk of peripheral arterial disease in the United Kingdom:2-year results of a prospective registry

We report a prospective 2-year, multicenter study of patients presenting with intermittent claudication (IC; ankle brachial blood pressure index, ABPI ≤ 0.9). Mean age of the 473 patients enrolled was 68 years, 20% were diabetics, 30% had prior symptomatic coronary heart disease (CHD), 7% had prior stroke, and 39% were current smokers. At baseline, 26.2% of patients had BP ≤ 140/85 mm Hg or lower and at 2 years this figure was 32.5% (P = .01). Current smokers had fallen to 27% (from 39%) at 2 years (P < .001). Use of antiplatelet agents, statins, and angiotensin converting enzyme inhibitors increased significantly during the course of the study as did claudication distance. Death and the composite of death, stroke or myocardial infarction (MI), occurred in 8.4% and 11.6% of patients, respectively. Prognosis was worse in patients with prior history of CHD, older age, those with diabetes and a lower ABPI.

Does the Kensey catheter keep a coaxial position inside the arterial lumen?: An in-vitro angioscopic study

Angioscopy was used to evaluate the “self-centering” ability of three Kensey catheters (KC) with different flexibility: one 8Fr “peripheral” and two 5Fr “coronary” (I & II). Angioscopic observations were made inside arteries. 5–18 mm in diameter. There was a good correlation between flexibility and self-centering of the KC [r=0.83, p<0.05]. Increasing the flow rate of rinsing solution from 18 to 60 ml/min prolonged coaxial position from 8.9±3.3 to 36±2.2 sec/min of activation [p<0.001]. A smaller effect on coaxial position was exerted by increasing cam speed from 5.2±0.7 to 19.2±1.6 sec/min (p<0.001). In conclusion, angioscopy showed that the KC has a limited ability to maintain a coaxial position inside the arterial lumen and operators cannot rely on its self-centering property.

Laser welding for coronary artery anastomosis: techniques, temperature profiles and the role of chromophores.

Laser vascular anastomosis is a developing technique which aims to employ the thermal effect of laser energy to achieve tissue fusion with minimal thermal damage. The tissue temperature necessary to achieve effective bonding is debated and must be related to the mechanism of fusion. Enhanced energy absorption at the anastomosis using chromophore (CR) dyes may improve technical success. Over 300 arteriotomies in porcine coronary arteries were welded in vitro using Argon (488/5 14 nm) and Nd:YAG (1060 nm) lasers with or without chromophore. Bursting pressures under saline infusion were measured and tissue temperatures during welding recorded using infrared thermal imaging. Results were as follows. Argon - CR (mmHg) [mean (s.e.)]: 249 (28). Argon + CR: 280 (22). Nd:YAG - CR: 1 5 1 (23). Nd:YAG + CR: 27 1 (30). The use of chromophore therefore increased the weld bursting strength for both lasers but this effect was statistically significant only for the Nd:YAG (p< 0.05, oneway ANOVA). Argon welds were stronger than Nd:YAG welds (p<0.O5) but this difference lost significance when chromophore was used. All welds required temperatures of around 100 degC to be effective and was inconsistent below 80 degC. In conclusion, vascular anastomoses produced by laser can withstand suprasystolic pressures. The effect of chromophore is to improve weld strength and consistency and furthermore, to visibly reduce thermal damage and facilitate beam aiming. These are considerable technical advantages.

Popliteal pseudoaneurysm secondary to a tibial osteochondroma: diagnosis with multi-detector row computed tomographic angiography.

A 17-year-old male presented with right knee pain following mild trauma whilst playing badminton. He subsequently developed a popliteal pseudoaneurysm secondary to trauma from a tibial osteochondroma. This is a recognised though very rare occurrence. Its appearance is reported for the first time using multi-detector row computed tomographic angiography (MDCTA). The clinical presentation and management of the popliteal pseudoaneurysm are outlined and the imaging findings are illustrated. There is increasing usefulness of MDCTA as an accessible, accurate, non-invasive clinical tool in the emergency diagnostic setting. Its use in the management of this unusual condition is demonstrated with emphasis on 3D, multi-planar reconstruction post-processing techniques.

Embolisation from atrial myxomas: a cause of acute on chronic limb ischaemia

Cardiac myxomata account for 50% of all primary cardiac tumours, 75% of them arising in the left atrium. ~ They are rare, occurring in up to 0.03% of postmortems. 2 The clinical presentation of myxomas can be misleading. Systemic manifestations include embolisation and non-specific constitutional features mimicking connective tissue diseaseY A case of left atrial myoma presenting with peripheral embolisation causing acute on chronic lower limb ischaemia is presented, illustrating the importance of histological examination of embolic material retrieved at operation and the diagnostic uncertainty frequently associated with cardiac myxomata.

Laser vascular anastomosis―preliminary evaluation of a new anastomotic technique

Laser vascular anastomosis (laser welding) is a developing technique that em ploys the thermal effect of laser energy to achieve fusion of apposed vessel edges. The authors have attempted to establish a definitive technique by an investiga tion of the physical properties of laser welds. Porcine coronary arteriotomies were repaired in vitro by two different laser wavelengths (Argon [488/514 nm] and Nd:YAG [1064 nm]) and by use of chromophore dyes to enhance energy absorption at the anastomosis. Anastomatic bursting strength was measured directly by means of saline infusion and vessel constriction (caused by diffusion of heat from the weld) assessed by a constant-pressure flow rate model. Histo logic techniques were also employed to estimate the degree of thermal damage to the vessel. In all these respects optimal results were obtained by the Argon laser and use of the chromophore Basic Fuchsin. These repairs all burst at greater than 200 mmHg and were minimally constricted. Thermal tissue damage was accurately confined to the anastomotic site. This technique will, therefore, be employed in future studies.

Acute effects of a copper vapour laser on atheroma

The acute histological effects of a commercially available copper vapour laser (CVL) on normal and atherosclerotic arterial wall were studied. The multi-cyclic CVL produces a quasi continuous wave output at 511 nm (green) and 578 nm (yellow) [green/yellow ratio 2∶1]. Tissue craters were produced in segments of normal and atherosclerotic human femoral artery using a maximum of 8 J of laser energy delivered with a bare 1 mm quartz fibre in contact and perpendicular to the tissue. Crater dimensions and ablation volumes were determined histologically using an optical graticule. Ablation of atheroma was almost three times more efficient than ablation of normal arterial wall (p<0.001). A narrow zone of vacuolization and coagulative thermal damage lined the crater margins suggesting a predominantly photothermal ablative mechanism. In conclusion, selective ablation of atheroma using low power copper vapour laser light is possible. The CVL is an attractive alternative to the argon ion laser because of its low running costs and applicability to other medical disciplines. Therefore, its potential application in laser angioplasty merits further study, preferably using a modified optical fibretip delivery system.