Return to work, driving and other activities after varicose vein surgery is very variable and is influenced little by advice from specialists.

OBJECTIVES: To determine the effect of altering written advice on return to activities following varicose vein surgery. METHODS: During two consecutive four-month periods, 134 patients (84 female, median age 57 years) were given two different information booklets. The first booklet (76 patients) suggested 7-10 days before driving and 2-3 weeks before returning to work. The second booklet (58 patients) explicitly advised return to all activities as soon as possible. Patients were contacted 6 weeks following surgery. Advice was sought from motor insurance companies about their views on return to driving. RESULTS: There was huge variation in time to driving (0-35 days, median 7), work (1-45 days, median 14) and "all normal activities" (1-62 days, median 21), but no significant differences between the two groups. There were paradoxes in the delays to driving and different types of work. Delays to driving or work were longer after bilateral surgery (p=0.01). CONCLUSION: Changing written advice did not influence the time to return to activities following varicose vein surgery, which was highly variable. Other factors may influence recovery and may be challenging for specialists to change. Consistent advice is important when comparing recovery from different treatments.

The symptoms of varicose veins: difficult to determine and difficult to study.

OBJECTIVES: To investigate the activities which may exacerbate symptoms in patients with varicose veins. METHODS: Questionnaires sent to patients before clinics and at least six months later. RESULTS: Both questionnaires were returned by 149 of 203 patients (74%) but only 124 contained adequate data for comparison--55 from patients who had surgical treatment and 69 who had no surgery. At initial presentation, worsening of discomfort attributed to varicose veins was common during (58%) or after (48%) standing and in hot weather (44%), but less when sitting with the feet down (31%), and after (31%) or when walking (19%). Surgery significantly reduced the total number of symptoms reported by patients at follow-up (p<0.02). However, none of the symptoms reported during specific activities was significantly lessened by surgery compared with no treatment--possibly because the attrition of patients during the study resulted in small numbers for analysis. CONCLUSIONS: Symptoms are a common indication for treating varicose veins and it is therefore important to be sure that they are due to the veins, rather than other causes. This report highlights traditional and logical questions which may help to identify symptoms caused by varicose veins but illustrates the difficulty of validating them.

Use of a pneumatic tourniquet improves outcome following trans-tibial amputation.

BACKGROUND: It is traditionally taught that a pneumatic tourniquet is contraindicated for trans-tibial amputations in patients with peripheral arterial disease. However, tourniquets are used successfully during total knee arthroplasty in elderly patients. Vascular patients undergoing a trans-tibial amputation have a high perioperative mortality and morbidity-notably the need for wound revision or a higher amputation level. We hypothesised that a tourniquet, used during amputation, would reduce blood loss and subsequent complications without compromising healing. METHODS: This was a prospective non-randomized study of 89 adult patients who underwent a trans-tibial amputation between January 2001 and December 2003. The endpoints were: haemoglobin levels, the need for blood transfusion, perioperative morbidity, revision rate and mortality. Patients were divided into two groups: a group with a pneumatic tourniquet (n=42) and a group without (n=47). RESULTS: The haemoglobin fall was 14.8% in the non-tourniquet group and 5.6% in the tourniquet group, with a higher need for transfusion in the non-tourniquet group. The revision rate was 14.3% in the tourniquet group and significantly higher in the non-tourniquet group (38.3%). Mortality was similar in both groups: 7.1% for the tourniquet and 6.4% for the non-tourniquet group. CONCLUSION: The use of a pneumatic tourniquet is safe and significantly reduces both blood loss and transfusion requirements during trans-tibial amputation. A pneumatic tourniquet reduces revision rates by over 50%, with subsequent cost savings.

Most patients with varicose veins have fears or concerns about the future, in addition to their presenting symptoms.

INTRODUCTION: This study aimed to document fears and concerns of patients about their varicose veins. REPORT: Completed questionnaires about symptoms and concerns were brought to clinic by 62% (203/329) patients referred with uncomplicated primary varicose veins. 'Concerns, worries or fears' about their veins were reported by 79%. These were seldom mentioned in referral letters, and included fears about thrombosis (31%), trauma (16%), ulcers (15%) and general concerns about the future (57%). DISCUSSION: Many patients have unrecognised fears and concerns about their varicose veins. Specific enquiry and reassurance about these is part of good management and may avoid unnecessary treatment.

Optical bistability involving photonic crystal microcavities and Fano line shapes.

The reflectivity of a single-channel waveguide mode upon resonantly coupling to a Kerr-active nonlinear resonant cavity is calculated analytically, including the effects of two-photon absorption. The resonant reflectivity takes the form of a Fano resonance because the solution includes linear reflections from perturbations downstream of the localized cavity. Instead of using a Hamiltonian formulation of the scattering problem, an intuitive set of basis states is used to expand the Green's function of the electric field wave equation. All resulting overlap functions describing the linear coupling between guided and localized states, and the nonlinear renormalization of the material's refractive index, are in terms of well-defined physical quantities. Although derived in the context of photonic crystal-based waveguides and cavities, the treatment is valid for any low-loss waveguide-resonator geometry that satisfies specific weak coupling criteria. For a cavity consisting of Al0.18Ga0.82As, hosting a localized mode at 1.55 microm with a Q of 4000 and a mode volume of 0.055 microm(3), we predict the onset of bistable reflection at incident powers of approximately 40 mW. The downstream reflections lead to hysteresis loops in the reflectivity that are topologically distinct from conventional Lorentzian-derived loops characteristic of isolated Fabry-Perot cavities. We provide a stability argument that reveals the unstable branches of these unique hysteresis loops, and we illustrate some of the rich bistable behaviors that can be engineered with such downstream sources.

Enhanced second-harmonic generation from planar photonic crystals.

Strongly enhanced second-harmonic generation is observed from a two-dimensional square lattice GaAs/AlGaAs photonic crystal waveguide when the fundamental beam, the second-harmonic beam, or both beams resonantly couple to a leaky eigenmode. P-polarized second-harmonic spectra are obtained for s-polarized, 150-fs pump pulses that are tuned from 5000 to 5600 cm(-1) and directed along the gamma-chi direction of the crystal for various angles of incidence. Compared with off-resonant conditions, enhancements of >1200x in the second-harmonic conversion are observed for resonant coupling of both the fundamental and the second-harmonic fields to leaky eigenmnodes. The angular and spectral positions of the peaks are in good agreement with simulations.

Renal dysfunction and prolonged visceral ischaemia increase mortality rate after suprarenal aneurysm repair.

BACKGROUND: Elective juxtarenal abdominal aneurysm repair has a significantly lower mortality rate than suprarenal repair. Identification of factors affecting outcome may lead to a reduction in mortality rate for suprarenal repair. METHODS: Data were collected prospectively between 1993 and 2000 for 130 patients who underwent type IV thoracoabdominal aneurysm (TAA) repair and 44 patients who had juxtarenal aneurysm (JRA) repair. Preoperative risk factors and operative details were compared between groups and related to outcome after TAA repair (there were only two deaths in the JRA group). RESULTS: The in-hospital mortality rate was significantly higher following TAA repair (20.0 per cent; 26 of 130 patients) than JRA repair (4.5 per cent; two of 44). Raised serum creatinine concentration was the only preoperative factor (P = 0.013) and visceral ischaemia the only significant operative factor (P = 0.001) that affected mortality after TAA repair. CONCLUSION: JRA repair was performed with similar risks to those of infrarenal aneurysm repair. Impaired preoperative renal function was related to death following TAA repair and conservative treatment should be considered for patients with a serum creatinine level above 180 micromol/l. Reducing the duration of visceral ischaemia might improve outcome.

Resonant scattering and mode coupling in two-dimensional textured planar waveguides.

A heuristic formalism is developed for efficiently determining the specular reflectivity spectrum of two-dimensionally textured planar waveguides. The formalism is based on a Green's function approach wherein the electric fields are assumed to vary little over the thickness of the textured part of the waveguide. Its accuracy, when the thickness of the textured region is much smaller than the wavelength of relevant radiation, is verified by comparison with a much less efficient, exact finite difference solution of Maxwell's equations. In addition to its numerical efficiency, the formalism provides an intuitive explanation of Fano-like features evident in the specular reflectivity spectrum when the incident radiation is phase matched to excite leaky electromagnetic modes attached to the waveguide. By associating various Fourier components of the scattered field with bare slab modes, the dispersion, unique polarization properties, and lifetimes of these Fano-like features are explained in terms of photonic eigenmodes that reveal the renormalization of the slab modes due to interaction with the two-dimensional grating. An application of the formalism, in the analysis of polarization-insensitive notch filters, is also discussed.

Endoluminal femoropopliteal bypass for intermittent claudication.

OBJECTIVES: (i) to describe our initial clinical experience with endoluminal femoropopliteal bypass using a technique developed in a cadaveric model; (ii) to identify areas requiring technical modification to improve patency and complication rates. DESIGN: prospective, experimental pilot study. MATERIALS AND METHODS: fourteen consecutive patients with disabling intermittent claudication and superficial femoral artery occlusion underwent endarterectomy through a groin incision and endoluminal placement of a polytetrafluoroethylene graft. Follow-up was by duplex ultrasound and arteriography. RESULTS: two endovascular technical failures required conversion to open surgery. The cumulative primary (1 degrees), 1 degrees-assisted and secondary (2 degrees) patency rates at 1 year were 35.7%, 42.8% and 71.4% respectively; at 2 years the patency rates were 14.3%, 31.2% and 57.1%. Twenty-three endovascular interventions were required to maintain graft patency in 10 patients. Five patients subsequently required conventional bypass, of whom two proceeded to major amputation because of graft infection. Seven endovascular grafts remain patent at a mean follow-up of 50 months. CONCLUSIONS: this minimally invasive surgical technique is feasible, with acceptable patency rates. However, considerable investment of time and resources is required to maintain graft patency. With increasing experience and improved technical design, this procedure may offer a real alternative to conventional surgery in patients disabled by short-distance claudication.

Potentiation of non-N-methyl-D-aspartate receptor-induced changes in blood pressure by substance P in rats.

Central release of substance P (SP) in the nucleus tractus solitarius (NTS) may potentiate the reflex responses evoked by baroreceptor afferent input to this medullary nucleus. The mechanism is not known but may involve modulation of responses produced by release of glutamate, the putative primary baroreceptor transmitter, at neurons within the NTS. The principal glutamate receptor subtype proposed to transmit baroreceptor afferent input at second-order neurons is the non-N-methyl-D-aspartate (NMDA) receptor. The present study examined the effects of microinjection of SP into barosensitive regions of the NTS on the depressor and bradycardic response induced by activation of non-NMDA receptors in the NTS by subsequent microinjection of (+/-)-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA), a non-NMDA receptor agonist. Substance P potentiated the non-NMDA receptor-induced depressor response to AMPA in the NTS, evoking a significantly larger change in blood pressure over the same time period. These data suggest that SP may modulate a non-NMDA-miediated component of the baroreflex to influence the control of arterial blood pressure by increasing the sensitivity of the baroreceptor reflex.

Intermittent claudication should not be treated by surgery.

This debate examines the proposition that surgery is unnecessary or obsolete in the management of intermittent claudication. The case for this argument is that many patients have stable disease or respond well to conservative measures, that claudication is an expression of a systemic cardiovascular illness and that surgery can be replaced by endovascular techniques with equal success, and less disadvantage in the event of treatment failure. The case against the motion is that claudication is associated with repeated cycles of ischaemia and reperfusion, and that these contribute to excess cardiovascular mortality states and, furthermore, that surgery is the only option to relieve symptoms for many patients, especially those with distal disease.