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Biomedical subjects

D J Scott

Publications and source records attributed to D J Scott.

At least 91 records · Page 5Linked to original sources

Calman, venous surgery and the vascular trainee.

BACKGROUND: Surgical training in Great Britain is undergoing inevitable changes to accommodate the processes of Higher Surgical Training. Junior surgeons have long argued that their training experiences have been haphazard or without satisfactory supervision. With the advent of changes following the Calman Report and the implementation of the Vascular Surgical Society recommendations, we have audited the venous surgical experience of vascular trainees in Great Britain. METHODS AND RESULTS: Questionnaires were sent to 90 vascular surgical trainees achieving an overall 76.7% response rate (n = 69). Just under half of the trainees had spent more than 12 months on a pure vascular firm. The majority of trainees had received formal training in sapheno-femoral junction ligation and sapheno-popliteal junction ligation. However, several areas of training were deemed insufficient at both the junior and senior trainee levels. Very few trainees gain instruction on deep venous surgery and the techniques of microsclerotherapy. CONCLUSIONS: Despite the participation of trainees in specialised vascular units, current training schedules fail to cover the field of venous surgery adequately. Training by vascular specialists needs greater focus and should be tailored to the trainee's experience on entry to their firm.

Health Care Surveys↗

Polytetrafluoroethylene femorodistal grafts: can the use of a vein collar offer patients a reasonable chance of success?

The growing number of patients with critical ischemia who lack a suitable autogenous vein for grafting pose a particular problem for the vascular team. In such patients the use of a polytetrafluoroethylene graft with a distal anastomotic vein cuff or patch has been advocated as an alternative to primary amputation. The use of such adjunctive techniques is reviewed through a 3-year retrospective study of 50 patients under the care of one surgeon. Data analyzed include patient demographics, risk factors, and presenting symptoms. All patients were included in a Duplex graft surveillance program. The cumulative patency rates at 1 and 2 years were 56% and 55%, respectively, with limb salvage rates of 85% and 80%. The data support a reconstructive approach to maintain the quality of the patient's life.

Aged↗

Impedance index measurements of in vitro PTFE end-to-side anastomoses: effect of angle and Miller cuff.

OBJECTIVE: To measure non-invasively the impedance index of a range of geometries of PTFE end-to-side anastomoses (ESA). DESIGN: In vitro experiments using a custom-built flow rig. SUBJECTS: Anastomoses constructed at each angle. (15 degrees, 30 degrees, 45 degrees, 60 degrees, 90 degrees, 120 degrees) for both standard and cuffed ESA. RESULTS: The impedance index of each ESA increased non-linearly with flow rate. The impedance index at a given flow rate was reduced by decreasing the anastomotic angle and further reduced by the addition of a Miller cuff. CONCLUSIONS: The reduction in impedance index achieved with a Miller cuff may help to explain the improved patency rates of femoropopliteal grafts incorporating a cuff.

Anastomosis, Surgical↗

Polytetrafluoroethylene (PTFE) femorodistal grafts with a distal vein cuff for critical ischaemia.

OBJECTIVE: To analyse the results of PTFE femorodistal bypass grafts using a distal anastomotic vein cuff in the treatment of critical ischaemia. DESIGN: Prospective study of consecutive patients under the care of a single Vascular Surgeon. SETTING: A dedicated Vascular Surgical Unit in a University teaching hospital. SUBJECTS: Fifty-one consecutive femorodistal PTFE grafts were performed on 50 patients (median 74 years, range 58-94 years, 25 men; median ankle:brachial index 0.4). In 28 (55%) a common ostium arteriovenous fistula (AVF) was fashioned at the distal anastomosis. RESULTS: The 30-day postoperative mortality was 8%, with 10 (21%) major complications. The 1 and 2 year primary patency was 64% and 51%, respectively, with corresponding limb salvage rates of 85% and 80%. The presence of an AVF did not significantly affect graft patency or patient survival, but appeared to hinder limb salvage. The latter effect may be due to bias in patient selection. CONCLUSION: PTFE femorodistal grafts with a distal vein cuff are a suitable alternative to autogenous saphenous vein in distal reconstructions for critical ischaemia. No conclusions can be made about the efficacy of an AVF in this context.

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Exercise-induced neutrophil activation in claudicants: a physiological or pathological response to exhaustive exercise?

OBJECTIVES: To assess the effect of exhaustive exercise on neutrophil activation and degranulation in claudicants and controls. We investigated the hypothesis that neutrophil activation and degranulation are normal responses to exhaustive exercise in healthy patients. DESIGN: This was a controlled experimental two-group study. MATERIALS: Exercise was performed using a fixed workload treadmill test. Neutrophil activation was assessed by flow cytometry of whole blood labelled with anti-CD11b mouse IgG, and neutrophil degranulation in terms of plasma elastase measured by enzyme-linked immunosorbent assay. METHODS: Twenty-eight claudicants with stage 1 chronic leg ischaemia, and 22 healthy controls were recruited. Blood and urine samples were collected before and after treadmill exercise. Claudicants exercised to their maximum walking distance, and controls at a higher "fatigue" workload for a maximum of 20 min. RESULTS: Exercise produced a brief but significant neutrophilia in both groups. Neutrophil CD11b expression increased significantly after exercise only in the claudicants, and was associated with a significant rise in plasma neutrophil elastase. These indices remained unchanged in the control group at all time points despite exercise at a fatigue level. CONCLUSION: The inflammatory response associated with exercise in claudicants is not simply a physiological response to exhaustive exercise.

Aged↗

Percutaneous transluminal angioplasty for intermittent claudication: evidence on which to base the medicine.

OBJECTIVES: This study aims to assess the impact of PTA on the quality of life (QoL) of claudicants and to analyse which patients and which arterial lesions derive the most benefit. DESIGN: A prospective observational study. MATERIALS: One hundred and seventeen claudicants undergoing PTA were studied; 35 patients had bilateral disease, whilst 82 had unilateral disease and underwent PTA to a solitary iliac lesion, solitary superficial femoral or a iliac lesion above a diseased superficial femoral artery in 24, 39 and 19 cases, respectively. METHODS: Patients completed the Short Form 36 (SF36) and EuroQol (EQ) QoL assessment instruments prior to and at 1, 3, 6, and 12 months following intervention. The SF36 produces a QoL profile, whilst the EQ produces two QoL indices. RESULTS: Claudication has a deleterious effect on QoL, especially in patients with multi-segment disease. PTA results in an immediate and lasting improvement in the QoL of claudicants. Unilateral claudicants undergoing PTA to a solitary iliac lesion demonstrate the most marked QoL benefits and 12 months post PTA report a QoL approaching that of an age-matched population. Patients with bilateral claudication undergoing unilateral PTA and unilateral claudicants undergoing PTA to a solitary SFA lesion demonstrate some QoL benefits, but at 12 months post PTA do not approach the QoL scores of an age-matched population. Unilateral claudicants undergoing iliac PTA above a diseased SFA demonstrate minimal QoL changes. CONCLUSIONS: These results should influence decision making in the management of claudication and it may be possible to prioritise PTA waiting lists to ensure patients with greatest potential benefit are treated with most urgency.

Adult↗

Reduced total antioxidant capacity predicts ischaemia-reperfusion injury after femorodistal bypass.

BACKGROUND: Antioxidant defence systems are essential to protect the body from harmful free radicals released following ischaemia-reperfusion. The aim of this study was to examine the total antioxidant capacity (TAC) of patients with chronic critical leg ischaemia undergoing femorodistal bypass and to correlate this with lipid peroxidation, changes in capillary permeability and clinical outcome. METHODS: Twenty-five patients, 15 men and ten women of median age 71 (range 62-79) years, and 15 matched controls were studied. Blood was taken before operation and after reperfusion, with assays performed for malondialdehyde (a product of lipid peroxidation) and total antioxidant capacity. Changes in capillary permeability were measured by changes in the urinary albumin:creatinine ratio (ACR) following reperfusion of the ischaemic leg and expressed as a percentage increase from the preoperative value. Clinical outcome in terms of the systemic inflammatory response syndrome (SIRS) was recorded. RESULTS: Vascular patients who developed clinical evidence of a systemic inflammatory reaction following revascularization had a significantly reduced TAC compared with the controls (490 versus 860 mumol/l; P < 0.01, Mann-Whitney U test). These patients also demonstrated an increase in lipid peroxidation (0.5 versus 0.25 mumol/l, P < 0.05) and vascular permeability, as measured by the percentage increase in ACR (365 versus 130 per cent, P < 0.01). CONCLUSION: Vascular patients with a lower TAC developed increased capillary permeability as a result of ischaemia-reperfusion, which progressed to SIRS. TAC may provide a test to identify 'at risk' patients. It may be possible to augment their defence with exogenous antioxidants.

Aged↗

Trials and tribulations of vascular surgical benchmarking.

BACKGROUND: Benchmarking is a new tool to assess the efficiency of different hospitals. Classification of operations using healthcare resource groups (HRGs) is related to parameters including number of cases, length of stay (LOS) and age profile. METHODS: A National Comparative Database was used to compare three hospitals. Analysis was confined to the major HRGs involved with vascular/venous surgery. RESULTS: For high-volume low-complexity varicose vein surgery, all three hospitals had similar numbers of patients and LOS. In contrast, the LOS for routine vascular operations in hospital A was double that in hospital B (16.3 versus 7.4 days). Hospital A had three times as many patients classified as 'other - peripheral vascular disease' as hospital C and six times as many as hospital B (329, 49 and 111 for hospitals A, B and C respectively). LOS following major amputation in hospitals A and C was nearly double that in hospital B (32.4, 18.3 and 33.6 days for hospitals A, B and C respectively). CONCLUSION: There were a number of significant variations between the three hospitals during the 9-month interval. Explanations included the methods of coding, local facilities including availability of rehabilitation beds and difference in the patients' age profiles. Benchmarking in its present format reveals a number of variations which may not necessarily reflect real differences in clinical performance.

Benchmarking↗

Comparison of POSSUM and the Portsmouth predictor equation for predicting death following vascular surgery.

BACKGROUND: The Physiological and Operative Severity Score for enUmeration of Mortality and morbidity (POSSUM) scoring system has been proposed as an accurate predictor of death which takes account of case mix. It appears to overpredict death, and may have drawbacks which prevent accurate individual or subgroup analysis. An alternative system, the Portsmouth predictor equation for mortality (P-POSSUM) may have overcome these problems, but its apparent advantage could be related to inappropriate analysis of POSSUM predictions. METHODS: Some 312 patients having arterial procedures were studied. POSSUM and P-POSSUM scores were used to predict death and compared with actual outcomes. The observed:predicted (O:E) mortality ratios were calculated by two methods for each of the scoring systems. First the analysis devised by the inventors of POSSUM was used and second the method devised for P-POSSUM. RESULTS: The O:E ratio for POSSUM using its recommended 'exponential' method of analysis was 1.14, but it was 0.59 if the P-POSSUM 'linear' analysis was used. The O:E ratio for P-POSSUM using its correct method of analysis was 0.89, but it was 0.67 if the method of analysis devised for POSSUM was used. CONCLUSION: The O:E ratios for POSSUM and P-POSSUM were close to unity when the appropriate analysis was performed. Both POSSUM and P-POSSUM overpredicted death if the incorrect analysis was used.

Aged↗

Prospective analysis of quality of life in patients following infrainguinal reconstruction for chronic critical ischaemia.

BACKGROUND: The aims of this prospective study were to analyse the health-related quality of life (QOL) changes associated with infrainguinal arterial reconstruction for chronic critical limb ischaemia (CLI) and to assess the impact of graft patency and limb salvage. METHODS: Fifty-five consecutive patients, 28 women and 27 men of median age 71 (range 41-86) years, undergoing infrainguinal arterial reconstruction for CLI, consented to participate in the study. QOL was assessed using the Short Form 36 (SF36) health survey questionnaire, which was completed before and at 1, 3, 6 and 12 months following surgery. Graft patency was assessed by duplex imaging at the same postoperative intervals. RESULTS: CLI severely impaired QOL. Cumulative graft patency at 1, 3, 6 and 12 months after surgery was 82, 78, 76 and 64 per cent respectively. Reconstruction resulted in significant improvements in the SF36 domains Physical Functioning, Pain, Vitality and Social Functioning (P< 0.01). With a patent graft these improvements began soon after surgery and were maintained for the 12 months studied. Following irredeemable graft occlusion, patients who had secondary amputation also described some QOL improvements. CONCLUSION: A patent graft following infrainguinal arterial reconstruction for critical ischaemia results in an immediate and lasting improvement in health-related QOL.

Activities of Daily Living↗

Preoperative duplex imaging is required before all operations for primary varicose veins.

BACKGROUND: Physical examination is unreliable in the detection of sources of reflux in varicose veins. Hand-held Doppler (HHD) ultrasonography has been recommended as an accurate adjunct to physical examination. The aim of this study was to evaluate the accuracy of HHD imaging in comparison with duplex ultrasonography. METHODS: Eighty-nine legs in 61 patients with primary varicose veins were examined with an HHD probe to detect reflux at the saphenofemoral junction (SFJ), the saphenopopliteal junction (SPJ) and in thigh perforators (TPs). Patients then underwent duplex imaging and the results of the tests were compared. RESULTS: The sensitivity of the HHD technique was 73 per cent at the SFJ, 77 per cent at the SPJ and 51 per cent for TPs. In primary varicose veins the surgery planned using HHD imaging alone would have left residual sites of reflux in 24 per cent. CONCLUSION: Examination with HHD ultrasonography is not sufficiently accurate to plan varicose vein surgery. Duplex imaging is recommended before all operations for primary varicose veins.

Humans↗

HRGs for benchmarking and contractual arrangements: a poisoned chalice?

A study was undertaken to determine if healthcare resource groups (HRGs) are reliable, reproducible in different centres and accurately reflect clinical activity. During a 3 month period, 385 finished consultant episodes (FCEs) were assessed. Of these, 17 (4.4%) were grouped to U01, i.e. no group allocated as the primary diagnosis was not recorded. For 271 of these episodes, a clinician had also allocated a choice of what he thought the HRG should be. These choices of HRG were then compared with the official grouping determined by the software provided by the National Casemix Office (NCMO). Disparities between 'automatic grouping' and proposed HRG assignment by the consultants occurred in 20.66% (56/271). Version 3 should see some of these disparities and actual grouping software errors reduced, in particular through the introduction of a new vascular surgery chapter. However, the absence of a primary diagnosis will still produce the allocation of group U01 in version 3. Caution should be observed in using the HRG software and in the interpretation of data obtained from it. This could be especially important in benchmarking or contractual settings as there may be adverse implications to the unit/hospitals involved.

Benchmarking↗

Correlating clinical indicators of lower-limb ischaemia with quality of life.

The objectives of the study were to analyse the impact of increasing lower-limb ischaemia upon quality of life and to assess the correlation between clinical indicators of lower-limb ischaemia and such quality. A prospective observational study of a consecutive series of 235 patients (144 men and 91 women; median age 68 (range 41-87) years presenting with varying degrees of lower-limb ischaemia graded according to ISCVS criteria was performed. Data was collected at interview before any intervention. Clinical indicators of lower-limb perfusion included: intermittent claudication and maximum walking distance on standardized treadmill testing; ankle:brachial pressure indices and isotope limb blood flow. Quality of life analysis was performed using the EuroQol (EQ) questionnaire. This is a standardized generic instrument for describing health-related quality of life and consists of a descriptive system of five dimensions, each measured on three levels. Thus, a profile and two single indices of quality of life were derived using different methods. Increasing lower-limb ischaemia results in a statistically significant deterioration in both global quality of life and in all EQ-measured quality of life dimensions (P < 0.01 Kruskal-Wallis, ANOVA). The correlation between clinical indicators and quality of life is statistically significant but not sufficiently close (correlation coefficients < 0.6) to assume that variations in clinical indicators result in reciprocal variations in quality of life. In conclusion, as might be expected, a significant correlation exists between clinical indicators of lower-limb ischaemia and health-related quality of life. However, the low correlation coefficients emphasize how tenuous the association is. Thus, a significant improvement in the clinical indicators of lower-limb ischaemia cannot be assumed to impart a similar benefit on quality of life. The latter concept must therefore be analysed independently.

Activities of Daily Living↗

Autologous blood transfusion: the benefits to the patient undergoing abdominal aortic aneurysm repair.

The clinical benefits of using intraoperative autologous blood transfusion during abdominal aortic aneurysm bypass surgery become increasingly apparent when use of autologous and homologous blood transfusions is compared. That homologous blood transfusions carry some risk is widely recognized. When autologous blood is used as a sole source of blood transfusion, the risk of transmission of infectious agents and potential immunologic side effects are avoided. A prospective randomized pilot study comparing autologous and homologous blood transfusion in patients undergoing elective infrarenal abdominal aortic aneurysm bypass surgery was undertaken. The purpose of this study was to determine whether autologous blood salvaged intraoperatively may serve as an alternative to homologous blood by comparing the rate of postoperative infection and duration of hospital stay for patients receiving autologous versus homologous blood transfusions. Fifty patients undergoing abdominal aortic aneurysm bypass surgery were prospectively randomly assigned to receive either a homologous or an autologous blood transfusion, with 27 receiving a homologous blood transfusion and 23 receiving an autologous blood transfusion. The data from this study show that the length of hospital stay of patients receiving an autologous blood transfusion intraoperatively was reduced by a mean of 3 days and the risk of postoperative complications such as a systemic inflammatory response or sepsis, was reduced by more than 50%.

Aged↗