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Biomedical subjects

Y G Wilson

Publications and source records attributed to Y G Wilson.

31 records · Page 2Linked to original sources
PubMed1995

Preferential use of vein for above-knee femoropopliteal grafts.

OBJECTIVES: Many centres preferentially use polytetrafluoroethylene (PTFE) for above-knee femoropopliteal bypass as surgery is simplified and patency rates are comparable to vein, which is preserved for subsequent revisions or for distal disease progression. In this Unit, vein remains first choice graft material. The aim of this study was to audit our results with respect to above-knee bypass to establish the demand for vein for secondary reconstruction and to document the ultimate fate of the limb. PATIENTS: Between 1983 and 1992, 112 above-knee reconstructions were performed on 109 patients (89 vein and 23 PTFE grafts). PTFE was used where vein was absent or inadequate. Life table analysis of primary graft patency, limb salvage and patient survival up to 36 months follow-up concurs with previously reported series. RESULTS: Twenty-eight vein grafts (31%) and 11 PTFE grafts (48%) occluded during a median follow-up of 64 months (8-116 months). In only four cases was vein required for secondary procedures. The remainder were salvaged by thrombectomy and local procedures for technical problems. Amputation rates following graft occlusion were 12% in the vein group (20% of these being above-knee) as against 26% in the PTFE group (80% above knee). CONCLUSIONS: The demand for vein for secondary procedures is low. Amputation rates when vein grafts do occlude are half those of PTFE and amputation level is significantly influenced by graft type. We advocate preferential use of vein in above-knee femoropopliteal bypass.

Adult↗
PubMed1995

The value of pre-discharge Duplex scanning in infrainguinal graft surveillance.

OBJECTIVES: Protocols and criteria for Duplex-based graft surveillance programmes (GS) vary widely as to the optimum regimens for maximising detection of "at risk" grafts. Few centres recommend starting GS before discharge. The aim of this study was to audit our experience with respect to early scanning. SETTING: Vascular Studies Unit, Bristol Royal Infirmary. METHOD: The records of 123 patients entering GS from January 1992 were reviewed. Patients were scanned at 1 week, 6 weeks and 3, 6, 9 and 12 months post-bypass. Haemodynamic criteria used were a peak mean velocity (PMV) less than 45 cm/s and a focal velocity disturbance with a V2/V1 ratio of 1.5 or more. RESULTS: Forty-six abnormalities (37% detection rate) were identified on scans within one week. In all cases, on-table completion studies with either arteriography and/or flow measurements had failed to identify the anomalies subsequently detected by Duplex. At 1 week, six grafts had occluded, 27 had a focal PMV increase (mean V2/V1 ratio: 2.6; range 1.5-4.3), four had low flow velocities, four had arteriovenous fistulae, one contained mobile thrombus, two had retained cusps and two had hamstring entrapment. Of 40 patent, but compromised grafts, 18 warranted immediate investigation. Of the 27 patients with velocity disturbances on Duplex, 25 were simply observed but, eight have since required intervention for definitive stenoses at these sites which, in retrospect, were evident within the first postoperative week. CONCLUSIONS: Pre-discharge scanning is a useful modality for detecting technical problems. Intrinsic graft abnormalities, possibly the sites of future definitive stenoses, have been visualised even at 1 week and once identified, can be more closely scrutinised thereafter. Pre-discharge colour Duplex is recommended as standard practice for quality control after infrainguinal bypass.

Arterial Occlusive Diseases↗
PubMed1995

Quantitative endoluminal measurements during angioscopy: an innovative technique.

AIM: To evaluate angioscopy in this Unit with respect to its application in lower limb vascular reconstructions. By providing magnified, colour images of the luminal surfaces of vein grafts, anastomoses and native arteries, angioscopy allows direct visualisation of imperfections and is sensitive in diagnosing technical problems. However, assessment is qualitative and magnification of the image can distort the operator's impression of true size. Angioscopy would be more versatile if it were possible to quantify the observed images. METHOD: A new technique has been developed to measure intra-luminal diameter from the angioscopic images. A linear displacement transducer is attached to the angioscope and accurately monitors its axial shift. Signals from the transducer are received by a personal computer equipped with a video frame grabber and analogue digital converter, together with appropriate software. The computer generates calculated dimensions based on geometrical principles, once each angioscope has been appropriately calibrated at the outset. RESULTS: Laboratory studies examining tubes of known dimensions have confirmed the reproducibility and accuracy of the technique. Simultaneous angioscopic and Duplex ultrasound measurements of the internal diameters of segments of vein suspended in a water bath were then carried out. Using the Duplex results as the 'gold standard', there was a strong correlation between the measurements obtained with the two techniques (Rs = 0.92). CONCLUSIONS: In the clinical context, this system has the capability to generate accurate endoluminal measurements during angioscopy. This has application for quality control in the selection of veins and inspection of run-off vessels during bypass grafting and in completion studies, following both operative and percutaneous procedures.

Analog-Digital Conversion↗
PubMed1995

Non-invasive aortoiliac assessment.

OBJECTIVES: To assess the accuracy of Duplex ultrasound in the assessment of aortoiliac disease. DESIGN: Prospective, semi-blind study. SETTING: Vascular laboratory and radiology departments, University Hospital. MATERIALS AND METHODS: Ninety-two patients underwent assessment of the aortoiliac segment by femoral pulse palpation, Duplex ultrasound and biplanar arteriography. Of these 184 aortoiliac segments, 68 were also assessed by intraarterial pressure measurements and 80 by magnetic resonance angiography (MRA). MAIN RESULTS: Femoral pulses were abnormal in all 32 occluded aortoiliac segments. Of 152 patent segments, femoral pulse palpation was misleading in 50 (33%). MRA detected all occlusions and had a sensitivity of 71% and specificity of 68% for stenoses, compared to arteriography. Colour flow Duplex misdiagnosed four occlusions as stenoses. Duplex had a sensitivity of 91% and specificity of 93% for stenoses when compared to arteriography. Two stenoses, detected by Duplex and confirmed by pressure gradients, were missed by arteriography. CONCLUSIONS: Pressure measurements remain the gold standard for aortoiliac examination, arteriography providing only morphological information. The limitations of femoral pulse palpation should be appreciated. Although MRA was faster, Duplex examination proved slightly more sensitive to stenoses. At present, colour Duplex provides the best non-invasive assessment of aortoiliac disease and could prevent unnecessary arteriograms.

Aorta, Abdominal↗
PubMed1994

Influence of compression stockings on lower-limb venous haemodynamics during laparoscopic cholecystectomy.

Lower-limb venous haemodynamics were studied prospectively in 40 patients (24 women, 16 men of median age 52 years) undergoing laparoscopic cholecystectomy. Patients were randomized to wear compression stockings during surgery or no stockings. All received subcutaneous heparin prophylaxis. Venous capacitance and outflow were measured non-invasively before, during and after pneumoperitoneum. In the group without compression stockings (20 patients) venous capacitance and outflow decreased during pneumoperitoneum in most patients. In the group wearing stockings (20 patients) the changes were less pronounced or abolished. There was a significant difference between the groups in venous capacitance and outflow ratios at mid-operation: median (interquartile range) 0.89 (0.56-1.16) and 0.89 (0.56-1.15) respectively in the group without stockings versus 1.48 (1.09-2.19) and 1.71 (1.20-2.19) respectively in that with stockings (P < 0.001). Pneumoperitoneum creates a significant resistance to venous return. Compression stockings counteract the changes observed.

Adult↗
PubMed1994

Immunocytochemical staining of pS2 protein in fine-needle aspirate from breast cancer is an accurate guide to response to tamoxifen in patients aged over 70 years.

Fine-needle aspirates from 52 breast cancers in 50 patients over 70 years of age were immunocytochemically stained for pS2 protein. All patients were treated with tamoxifen 40 mg/day and followed up at intervals of 2 months. The size of the tumour was serially assessed with calipers and portable ultrasonography. Change in tumour size was confirmed mammographically. Clinical monitoring was performed bind of the pS2 status. Twenty-five tumours were pS2 positive, of which 23 showed a significant response; ten went into complete remission (mean time to complete remission 6.8 (range 2-14) months) and 13 demonstrated partial remission (mean follow-up 8.9 (range 6-19) months). Two tumours remained static. Twenty-seven tumours were pS2 negative and none of these responded to tamoxifen; six remained static (mean follow-up 11.5 (range 6-14) months) and 21 progressed (mean time to progression 7.0 (range 3-14) months) (P < 0.001). Immunocytochemical assessment of fine-needle aspirates from elderly women with breast cancer accurately predicts a worthwhile response to tamoxifen.

Adult↗
PubMed1994

Pulse-generated run-off versus dependent Doppler ultrasonography for assessment of calf vessel patency.

Pulse-generated run-off (PGR) is an established technique in the assessment of calf vessel patency. Dependent Doppler ultrasonography is proposed as a fast and simple alternative. Twenty-six limbs with severe ischaemia were evaluated by PGR, dependent Doppler examination and intra-arterial digital subtraction angiography (DSA). PGR was performed and scored as previously described. Dependent Doppler ultrasonography was performed after 5 min of foot dependency and scored as for PGR. Angiograms were scored by an independent radiologist, who awarded 2 for a vessel widely patent to the ankle, 1 for a diseased vessel crossing the ankle and 0 if no vessel was visualized. Of 78 calf vessels evaluated, 59 (76 per cent) appeared patent on PGR and dependent Doppler examination but only 33 (42 per cent) appeared patent to the ankle with intra-arterial DSA. There was very good agreement between PGR and dependent Doppler for detection of patent calf vessels (kappa = 0.93). Doppler signals were biphasic in six calf vessels on dependency and in 22 vessels with PGR. PGR and dependent Doppler ultrasonography detected 26 vessels communicating with the pedal arch compared with seven detected angiographically. There was good agreement between PGR and dependent Doppler examination for diagnosis of the most suitable vessel for distal anastomosis (kappa = 0.80). The wide availability and simplicity of dependent Doppler ultrasonography mean that no patient with a critically ischaemic limb should be denied reconstructive surgery on the basis of angiographic findings alone.

Angiography, Digital Subtraction↗
PubMed1994

Magnetic resonance angiography or IADSA for diagnosis of carotid pseudo occlusion?

Accurate diagnosis of internal carotid artery (ICA) occlusion is essential in the investigation of carotid disease yet may be difficult using Duplex. Traditionally contrast arteriography has been used to confirm the diagnosis despite its cost and potential dangers. Twenty-one patients with 23 ICA occlusions were evaluated by a 3-dimensional time of flight magnetic resonance angiography (MRA) technique. The cervical carotids and circle of Willis were imaged during the MRA examination which lasted 30 minutes. Confirmatory conventional angiography was performed in all patients. Using angiography as the gold standard, all occlusions were correctly diagnosed by MRA and 22 of 23 occlusions correctly diagnosed by Duplex. There was good agreement between MRA and angiography for all 42 ICAs imaged (Kappa statistic 0.83). Diagnosis of internal carotid artery occlusion is critical as it determines the need for operation. In this situation MRA provides a useful non-invasive complement to Duplex. A combination of non-invasive studies may enable arteriography to be rejected with greater confidence in this high risk group.

Angiography, Digital Subtraction↗
PubMed1994

Intramuscular diclofenac sodium for postoperative analgesia after laparoscopic cholecystectomy: a randomised, controlled trial.

Laparoscopic cholecystectomy is the surgical treatment of choice for symptomatic gallstones. Nonsteroidal antiinflammatory drugs offer effective analgesia, avoiding the central side effects of opiate drugs. To assess intramuscular diclofenac sodium (Voltarol; Ciba-Geigy) after laparoscopic cholecystectomy, 55 consecutive patients (41 female; 14 male; mean age: 50 years) were randomised to receive either diclofenac or placebo in double-blind fashion. Six patients were withdrawn from study (three conversions to open cholecystectomy; three incomplete documentation). Pain scores were assessed at 4, 24, and 48 h using a linear analogue scale; opiate consumption and time to first oral fluid and food were recorded. In 26 patients receiving diclofenac, median scores at 4 h were 1.6 (range 0-7.6) as compared with 4.1 (range 0-7.6) in 23 control patients (p = 0.05, 95% confidence limits 3.2, 0; Mann-Whitney U test). Nausea scores, return to diet, and time to discharge did not differ significantly between the groups. Intramuscular diclofenac significantly reduces early postoperative pain after laparoscopic cholecystectomy and is worthy of consideration if the procedure were ever undertaken as day case surgery.

Adolescent↗
PubMed1993

Long-term follow-up of Swanson's silastic arthroplasty of the metacarpophalangeal joints in rheumatoid arthritis.

77 patients with rheumatoid arthritis, 62 female and 15 male, underwent metacarpophalangeal joint arthroplasty on 375 joints using the Swanson design silicone rubber spacer between 1976 and 1985. Retrospectively, 48 of these patients were evaluated by postal questionnaire and 35 of them also underwent objective assessment at intervals ranging from five to 14 years post-operatively. Objective variables recorded included range of active motion, recurrence of ulnar drift and radiographic appearances. Both in the early and late stages, the vast majority of patients were satisfied with the outcome, with abolition of pain, correction of deformity and improved range of motion. There was some loss of mobility with time. However, functional improvement was maintained in the majority. Complication rates compare favourably with other reported series and no case of silicone synovitis was diagnosed. We agree with previous studies that the procedure is useful for lasting relief of pain and enhancement of a patient's sense of well-being and is associated with few complications.

Arthritis, Rheumatoid↗
PubMed1991

Intra-arterial streptokinase infusion in acute lower limb ischaemia.

Between 1986 and 1988, 38 patients (29 men and nine women), median age 65 years (range 38-85 years), underwent local intra-arterial streptokinase therapy for acute lower limb ischaemia. Three patient groups were identified: 15 with acute on chronic ischaemia (group 1), 12 postangioplasty (group 2) and 11 postfemorodistal bypass (group 3). Distal arteriographic run-off was a significant discriminant between success and failure in group 1 (n = 15, chi 2 = 11.5, P = 0.001) and in the overall group (n = 38, chi 2 = 17.2, P less than 0.001). In group 2, four patients with good run-off had an unsuccessful outcome; this was due in all cases to technical problems (haemorrhage in two and intimal dissection in two). In group 3, two patients with good run-off had unsuccessful streptokinase infusions. In both cases the graft failed in the early postoperative period (less than 30 days). By contrast, the four patients whose grafts occluded after 30 days had successful streptokinase infusions and long-term graft patency was achieved by further surgery and balloon dilatation. In all groups, no patient with a poor run-off had a successful outcome following streptokinase administration. The role of local intra-arterial streptokinase therapy in the critically ischaemic limb remains controversial, but these results suggest that an adequate run-off is an important factor in the selection of patients for treatment.

Acute Disease↗
PubMed1983

Standardised trunk asymmetry scores. A study of back contour in healthy school children.

This paper reports a new method for expressing numerically asymmetry of the contour of the back in a forward-bending position. Information is given at three spinal levels (T8, T12 and L3) for 636 schoolchildren aged 8 to 15 years. Rib-hump and lumbar-hump scores were standardised to create trunk asymmetry scores (TASs) making comparison possible between children of different age, size and sex. Two groups of children were defined: those with clinically straight spines (585 children); and those with clinical evidence of lateral spinal curves (51 children). In the children with clinically straight spines the main findings were: about 1:4 had objectively detectable rib and lumbar humps; female-to-male ratios were 1.2:1 for the thoracic region and 1.4:1 for the lumbar region; right humps were about 10 times more common than left; TASs in the boys and girls at each spinal level had normal distributions about means to the right of zero (where zero represents perfect symmetry); at T8 and T12, a wider scatter of TASs in girls than in boys; at L3, larger TASs in girls than in boys; a relation between shortening of one lower limb and a contralateral hump on the back; and no relation to age (except at L3), stature (corrected for age) or handedness. The findings are discussed in relation to possible causes of back contour asymmetry, early diagnosis of scoliosis by screening, sexual dimorphism and significance for the pathogenesis of idiopathic scoliosis. Ten children with clinically straight spines and larger TASs, and 42 out of 51 children with clinical evidence of lateral spinal curves in the forward-bending position attended for radiographic examination. Twelve children had "scoliosis curves" of 11 degrees or more as defined by the Scoliosis Research Society. The results are reported in relation to TASs, spinal curve angle (Cobb) and vertebral rotation.

Adolescent↗