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Biomedical subjects

M R Whyman

Publications and source records attributed to M R Whyman.

16 recordsLinked to original sources
PubMed1998

Variation in management of intermittent claudication by vascular surgeons in Scotland. Scottish Vascular Audit Group [corrected].

OBJECTIVES: The principal aim was to determine the extent to which intended and actual management varied among vascular surgeons. DESIGN: Prospective survey. METHODS: A nationwide survey of initial management of, and determination of subsequent surgical management in, 1180 patients with a diagnosis of intermittent claudication made by 28 vascular surgeons was carried out in Scotland. RESULTS: The proportion of patients considered for conservative management varied between consultants from 10-83% (mean 42%, S.D. 16%). The proportion considered for angiography varied from 13-80% (mean 46%, S.D. 14%). For surgery, the range was 4-68% (mean 37%, S.D. 14%) and for angioplasty the range was 13-90% (mean 49%, S.D. 19%). All differences in management intention between consultants were significant (p < 0.001). The differences between consultants in terms of treatment actually received within 6 months were less striking but still significant (p < 0.05). All consultants actually managed more patients conservatively than they had originally intended, but there was poor correlation between intended and actual practice. CONCLUSIONS: In Scotland the variations between surgeons in both intended and actual management are substantial. Large scale randomised controlled trials of treatment of claudication are urgently required to make clear the best treatment strategies.

Adult↗
PubMed1997

Is intermittent claudication improved by percutaneous transluminal angioplasty? A randomized controlled trial.

PURPOSE: Percutaneous transluminal angioplasty (PTA) is an increasingly popular invasive treatment for peripheral arterial disease, but there have been very few controlled trials to justify its use. This randomized controlled clinical trial was performed to determine in patients with mild and moderate intermittent claudication differences in outcome between PTA and conventional medical treatment after 2 years. METHODS: Six hundred patients with claudication were screened at the Peripheral Vascular Clinic, Royal Infirmary of Edinburgh. Sixty-two patients with short femoral artery stenoses or occlusions (47 patients) and iliac stenoses (15 patients) were randomized to either PTA plus medical treatment (PTA group, 30 patients) or to medical treatment alone (control group, 32 patients). Medical treatment consisted of daily low-dose aspirin and advice on smoking and exercise. Outcome measures studied were patient-reported maximum walking distance, exercise treadmill distance until onset of claudication, treadmill maximum walking distance, ankle-brachial pressure index (ABPI), quality of life (Nottingham Health Profile), and duplex ultrasound-measured extent of occlusive disease. RESULTS: At 2 years of follow-up, the PTA group and control subjects did not differ significantly in patient-reported maximum walking, treadmill onset to claudication, treadmill maximum walking distances, or ABPI (p > 0.05). However, the PTA group had significantly fewer occluded arteries (p = 0.003) and a lesser degree of stenosis (expressed in terms of the velocity ratio; p = 0.004) in patent arteries. Quality of life was not demonstrably different between the two groups (p > 0.05). CONCLUSIONS: Two years after PTA, patients had less extensive disease than medically treated patients, but this did not translate into a significant advantage in terms of improved walking or quality of life. There are important implications for patient management and future clinical research.

Adult↗
PubMed1996

Randomised controlled trial of percutaneous transluminal angioplasty for intermittent claudication.

OBJECTIVES: To determine differences between PTA and conventional medical treatment in treadmill distance until onset of claudication, treadmill maximum walking distance, patient reported maximum walking distance, ankle brachial pressure index (ABPI), quality of life (Nottingham Health Profile, NHP) and Duplex measured extent of occlusive disease. DESIGN: Randomised controlled clinical trial. METHODS: Six hundred claudicants were screened. Fifty-one men and 11 women with intermittent claudication due to short femoral stenoses or occlusions (n = 47) and iliac stenoses (n = 15) were randomised to either PTA plus medical treatment (PTA group, n = 30) or to medical treatment alone (control group, n = 32). Medical treatment consisted of daily low dose aspirin and advice on smoking and exercise. RESULTS: At 6 month follow up: In the PTA group more patients reported no claudication (p < or = 0.05) and were asymptomatic on the treadmill (p < or = 0.01) compared to the control group. The ABPI was significantly higher in the PTA group. More of the PTA group reported lower NHP pain scores (p < or = 0.05). In the control group there were more occluded arteries (p < or = 0.001), and the stenosis velocity ratio of patient arteries was significantly higher (p < or = 0.001). CONCLUSIONS: Only 10% of claudicants had discrete lesions suitable for PTA. Treatment of these patients with PTA produces a greater short-term improvement in walking and quality of life than medical treatment alone and is associated with less progression of disease.

Angioplasty, Balloon↗
PubMed1996

Upper gastro-intestinal disease in Scotland: a survey of practice amongst Scottish gastroenterologists.

Given the range of causes of upper gastrointestinal disease (UGD), the evolving role of Helicobacter pylori in its pathogenesis and the variety of treatments available, one might expect complex management strategies in the management of these diseases. The aim of this study was to determine the current management strategies used in peptic ulcer disease and gastritis in Scotland and to identify areas where large and clinically important variations in practice exist between gastro-intestinal specialists. Between June and September 1994, 130 gastro-intestinal physicians and surgeons were sent a postal questionnaire based on their response to four hypothetical clinical scenarios. Eighty-one (63%) correspondents returned completed questionnaires. The case histories related to: bleeding duodenal ulcer; peptic ulceration whilst taking non-steroidal anti-inflammatory drugs (NSAIDs) and corticosteroids; management of dyspepsia in the young; and management of gastritis. Thirty-eight per cent of clinicians surveyed advocated the use of intravenous acid reducing agents in peptic ulcer bleeding. A total of 88% advocated endoscopic therapy in the presence of stigmata of recent haemorrhage and 5% suggested a follow up of endoscopy to confirm healing after ulcer bleeding. In treating the patient with ulcer while on NSAIDs, 45% of clinicians would use H2 receptor antagonists, 37% would use omeprazole, 14% misoprostol and 4% helicobacter eradication. Of the clinicians surveyed, 63% said they would investigate a 25-year-old patient with dyspepsia by endoscopy and 84% of these will biopsy for H. pylori. Empirical treatment was favoured by 37% and 4% considered a barium meal. There was no consensus in the treatment of gastritis. There exists considerable divergence of opinion between clinicians in investigation and treatment of upper gastrointestinal disease. The role of endoscopy, the type and duration of medical treatment of bleeding and non bleeding ulcer and gastritis require further, more detailed investigation. A consensus document would be warmly welcomed.

Adult↗
PubMed1994

Extracranial carotid artery flow measurement during carotid endarterectomy using a Doppler ultrasonographic flowmeter.

A study was performed to evaluate immediate changes in carotid artery blood flow after carotid endarterectomy using a Doppler ultrasonographic flowmeter. Forty-seven consecutive patients aged 49-78 (median 64) years with symptomatic internal carotid artery (ICA) stenosis underwent carotid endarterectomy. Volume flow, resistance and pulsatility index were measured in the common carotid artery (CCA) and ICA both before and after operation. ICA flow increased by 54 per cent (P < 0.01) and resistance decreased by 58 per cent (P = 0.01). CCA flow rose by 17 per cent (P = 0.1) and resistance fell by 21 per cent (P = 0.02). The pulsatility index did not change significantly. The Doppler ultrasonographic flowmeter offers a simple, non-invasive and convenient means of improving understanding of the immediate haemodynamic effects of carotid endarterectomy. It is useful in everyday practice to confirm the adequacy of endarterectomy, particularly in the absence of other methods of quality control. Duplex ultrasonography might still be necessary after surgery if the flowmeter does not demonstrate an increase in flow compared with the preoperative value.

Aged↗
PubMed1994

Trends in vascular surgery since the introduction of percutaneous transluminal angioplasty.

Lower-limb percutaneous transluminal angioplasty (PTA) has been used increasingly over the past decade, either alone or in conjunction with arterial reconstructive surgery. However, its impact on operation rates has not been evaluated properly. Rates of vascular operations and PTAs performed per referral for peripheral arterial disease to the regional vascular service at The Royal Infirmary, Edinburgh, were calculated for the years 1986-1992. The overall rate of PTA for peripheral arterial disease increased ninefold over this period; that for critical ischaemia increased fivefold. Rates of aortic and femoral reconstruction for all peripheral arterial disease increased by 40 and 100 per cent respectively, but rates for critical ischaemia remained static. The major amputation rate rose by 47 per cent between 1986 and 1990, and thereafter reached a plateau. Increased use of PTA was not associated with a reduction in the number of vascular operations.

Amputation, Surgical↗
PubMed1993

Factors influencing the hyperaemic response after carotid endarterectomy.

Transcranial Doppler ultrasonography was used to evaluate serially the changes in middle cerebral artery blood flow velocity (MCAV) in 37 consecutive patients during the first 72 h after carotid endarterectomy to identify factors that may predispose towards postoperative hyperaemia. Within 6 h of endarterectomy, median MCAV in the operated hemisphere was 48 per cent (95 per cent confidence interval 37-60 per cent) above that on admission and remained 27 per cent (95 per cent confidence interval 19-37 per cent) higher at 72 h. There was a similar, but less marked, increase in MCAV in the contralateral middle cerebral artery during the same time period. There was no association between the postoperative increase in MCAV and clinical presentation, admission MCAV, the presence or absence of a residual neurological deficit or infarction on computed tomography before operation, carotid clamp time, shunt usage, internal carotid artery stump pressure or MCAV during clamping. The greatest increase in MCAV was observed in patients with internal carotid artery stenosis > or = 50 per cent and, more particularly, in those with preoperative evidence of impaired cerebrovascular reserve. In the latter patients, MCAV was 100 per cent above the admission level within 12 h of operation and was still 50 per cent raised at 72 h.

Blood Flow Velocity↗
PubMed1993

A prospective study of the natural history of femoropopliteal artery stenosis using duplex ultrasound.

A foreknowledge of impending femoral artery occlusion might allow prevention of a deterioration in ischaemia by percutaneous transluminal angioplasty (PTA) in the preocclusive stage. A window of opportunity exists before a femoral stenosis progresses to occlusion and its treatment by PTA becomes more difficult, riskier and associated with lower patency. The size of this window is unknown. This is the first report of a study of the natural history of femoral stenoses using Duplex ultrasound. The aims of the study were to determine in patients with symptomatic peripheral arterial disease: (1) the incidence of progression from stenosis to occlusion; (2) the change in severity of stenosis over time; and (3) the relationship between severity of stenosis and progression to occlusion. The velocity ratio (VR) of 43 femoral artery stenoses in 38 patients was measured by Duplex ultrasound. The examination was repeated after a median of 28 (range 5-76) weeks. Nine/43 (21%) stenoses progressed to occlusion within a median of 13 weeks. Little overall change in VR was demonstrable if occlusion did not occur. Only stenoses with a VR > 3 progressed to occlusion in the study period. The data suggest that severe stenoses progress more rapidly than moderate, with a relatively brief window of opportunity. If PTA is to be undertaken, stenoses with a VR greater than 3 should be treated with minimum delay.

Adult↗
PubMed1993

Accuracy and reproducibility of duplex ultrasonography in grading femoropopliteal stenoses.

PURPOSE: The aim of this study was to determine the accuracy of Doppler waveform characteristics in grading femoropopliteal stenoses and to determine the interobserver and intraobserver reproducibility of measuring the same waveform characteristics. METHODS: Thirty patients with isolated areas of stenosis found by arteriography were evaluated by color duplex sonography. Each patient underwent scanning by two observers on two separate occasions. Each observer was blind to the other's results. Doppler spectra were recorded in areas where color change suggested the highest velocity and also at the nearest normal proximal area. Peak systolic velocity, spectral broadening, and waveform configuration were measured at each site. RESULTS: An increase in peak systolic velocity of more than 200% accurately predicted a 50% or greater reduction in luminal diameter on angiography (70% sensitivity, 96% specificity). The presence of spectral broadening and an abnormal waveform shape were found to correlate poorly with the degree of stenosis. Analysis of variance showed no significant difference between observers in velocity measurements (p = 0.78). CONCLUSIONS: We conclude that although stenoses of greater than 50% can be distinguished from minor stenoses, more precise definition of the degree of narrowing is unlikely. The good repeatability of the velocity ratio makes it an excellent tool for monitoring major changes in the progression of disease.

Analysis of Variance↗
PubMed1993

Accuracy and reproducibility of duplex ultrasound imaging in a phantom model of femoral artery stenosis.

PURPOSE: The improvement of management strategies in patients with intermittent claudication might depend on a better understanding of the natural history of femoral atherosclerosis. The grading of stenoses, the monitoring of their progression, and the assessment of response to treatment are critically dependent on a method's accuracy and variability. Duplex ultrasound imaging provides a noninvasive way of measuring localized disease, but there has been relatively little objective evaluation of its accuracy and reproducibility. The aim of this study was to evaluate the accuracy and variability of duplex velocity ratio measurements of stenosis. METHODS: In a laboratory flow model of the femoral artery, 14 concentric and eccentric stenoses were examined five times by three sonographers. Measurements were then repeated with a standardized technique in which Doppler angle and aperture position were fixed, giving a total of 420 measurements. RESULTS: Velocity ratio showed good correlation with degree of stenosis, R2 = 0.996. Intraobserver variability was low, but interobserver variability was significant with more severe stenosis (p = 0.002, analysis of variance). Standardization of the technique did not improve accuracy or variability. The 95% confidence limit was +/- 20% for a single reading of velocity ratio for stenoses of > 50% diameter reduction. CONCLUSIONS: We conclude that duplex ultrasound imaging can be used to accurately grade arterial stenosis in this range, and the potential exists for noninvasive monitoring of the progression of preocclusive femoral atherosclerosis and its response to treatment. In addition, repeated measurements of velocity ratio over time should be made by the same observer.

Analysis of Variance↗
PubMed1992

Screening patients with claudication from femoropopliteal disease before angioplasty using Doppler colour flow imaging.

Time, expense, risk and discomfort are incurred by arteriography in patients with intermittent claudication who might be candidates for percutaneous transluminal angioplasty (PTA). A valid screening technique could reduce the need for arteriography in patients found to have lesions not amenable to PTA. Agreement between Doppler colour flow imaging (DCFI) and angiography for detecting haemodynamically significant lesions is high, but DCFI may not identify lesions suitable for angioplasty. A total of 36 limbs in 30 patients were studied using DCFI before angiography. Agreement between the two methods was excellent (kappa = 0.91), and the predictive accuracy of DCFI for lesions amenable to PTA was good (kappa = 0.78, sensitivity 94 per cent, specificity 85 per cent, positive predictive value 83 per cent, negative predictive value 94 per cent, overall accuracy 89 per cent). DCFI is a useful screening process that may prevent unnecessary angiography, with consequent financial savings and clinical benefit.

Aged↗