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C D Irvine

Publications and source records attributed to C D Irvine.

At least 19 recordsLinked to original sources
PubMed2001

Haemostatic devices.

Explore the source record for details and available documents.

Arterial Occlusive Diseases↗
PubMed2000

The association of platelet-derived growth factor receptor expression, plaque morphology and histological features with symptoms in carotid atherosclerosis.

Platelet-derived growth factor may influence smooth muscle cell migration and proliferation and, therefore, carotid plaque composition and stenosis. Platelet-derived growth factor receptor expression and histological features were compared in carotid plaques from symptomatic and asymptomatic patients. Immunocytochemistry and histology determined platelet-derived growth factor-alpha and -beta receptor expression, white blood cell infiltration, smooth muscle cell, elastin, cholesterol, collagen and intraplaque haemorrhage in carotid artery plaques removed at surgery or the post-mortem. Plaques with > 70% stenosis from asymptomatic (n = 10) and symptomatic patients (n = 27) had higher expression of platelet-derived growth factor and beta receptors and higher scores for macrophages and intraplaque haemorrhage than plaques with < 70% stenosis from asymptomatic patients (n = 33). Plaques with > 70% stenosis from symptomatic patients had significantly lower alpha receptor expression than plaques with > 70% stenosis from asymptomatic patients. The reduction of alpha receptor expression, which may inhibit smooth muscle cell migration, suggests that differential expression of platelet-derived growth factor receptor subunits in plaques may be related to symptoms.

Aged↗
PubMed2000

Clinical governance and the vascular surgeon.

BACKGROUND: Audit of adverse outcome might allow identification of substandard surgical results. To test this hypothesis statistical modelling was applied to two indicator vascular procedures (elective abdominal aortic aneurysm repair and carotid endarterectomy) with accepted adverse event rates. METHODS: Binomial statistical models for varying adverse event rates were constructed. A power calculation was used in an attempt to predict the case numbers required to determine substandard results for individual surgeons and vascular units. Two scenarios were considered: first a base adverse event rate of 6 per cent and surgical practice with 9, 12 and 24 per cent morbidity rates, and second a base adverse event rate of 3 per cent and surgical practice with 6, 9 and 12 per cent morbidity rates. RESULTS: A mean of 57 elective abdominal aortic aneurysm repairs and 70 carotid endarterectomies were performed per annum. The adverse event rate for both operations was 4 per cent. Power calculations revealed that 130 patients would need to be studied to detect a surgeon with an adverse event rate twice 6 per cent and over 280 patients would be required with an adverse event rate twice 3 per cent. To gather this number of patients 2 years of unit data and between 3 and 22 years of individual data would need to be studied for a base adverse event rate of 6 per cent. A base rate of 3 per cent requires 7-47 years for an individual and 4-65 years for the unit. With a base adverse event rate of 6 per cent, detection of widely variant surgical practice (four times the morbidity rate as base) requires only 21 procedures. CONCLUSION: Statistical modelling demands assumptions about accepted adverse event rates, confidence criteria and what constitutes substandard results. Data from large numbers of patients are required even for common operations with accepted adverse event rates. These data raise serious questions as to the feasibility of performing clinical governance on the basis of morbidity and mortality event rates alone.

Aortic Aneurysm, Abdominal↗
PubMed2000

A comparison of the mortality rate after elective repair of aortic aneurysms detected either by screening or incidentally.

OBJECTIVE: to compare predicted and actual mortality rates, using POSSUM scoring, after elective repair of abdominal aortic aneurysms (AAAs) detected from the Gloucestershire Aneurysm Screening Programme and those discovered incidentally. METHODS: a sample of 276 men undergoing elective AAA repair in Gloucestershire between 1991 and 1998 was studied. AAAs were either detected from the screening programme or were discovered incidentally and referred from other sources. Mortality data relating to these patients have been recorded prospectively. POSSUM scoring was performed retrospectively from patients>> notes in both groups and related to outcome (30 day and in-hospital mortality). POSSUM and P-POSSUM methodology were used to compare observed and predicted mortality rates. RESULTS: in the 276 men who had elective AAA repair, the overall mortality rate was 7%. Mortality was lower in screen-detected AAAs (3/111, 3%) than AAAs discovered incidentally (16/175, 9%) (p=0.05). Preoperative physiology scores were significantly lower in men with a screen-detected AAA (median 19, range 13-29 versus 21, 12-41, p<0.001). POSSUM operative scores were similar between the groups. Actual versus predicted death ratios in the sample group were more accurate using POSSUM (ratio 0.93) than P-POSSUM (2.38) analysis. CONCLUSIONS: men with a screen-detected AAA had a lower mortality rate after elective repair than in those detected incidentally; lower preoperative physiology scores suggested they were fitter (as well as younger). In this study POSSUM analysis more accurately predicted outcome than P-POSSUM.

Age Distribution↗
PubMed2000

Stent-graft treatment for bleeding from a presumed aortoenteric fistula.

PURPOSE: To describe a technique for the endovascular treatment of aortoenteric fistula. METHODS AND RESULTS: A 67-year-old man who had undergone aortobi-iliac grafting for aneurysmal disease 8 years previously presented with life-threatening upper gastrointestinal hemorrhage. Endoscopy after resuscitation did not identify the source of the bleeding. Computed tomographic (CT) scanning and angiography revealed pseudoaneurysm formation at the upper anastomosis 1 cm below the renal arteries. Measurements were taken for endovascular repair. Uncomplicated emergency aortic endografting for exclusion of the pseudoaneurysm was performed using a 28-mm x 3.75-cm AneuRx device. Gastrointestinal hemorrhage ceased. CT scanning at 6 months confirmed the absence of a pseudoaneurysm, and the patient remains symptom free at 18 months. CONCLUSIONS: Endovascular treatment of aortoenteric fistula may represent a technique for treating gastrointestinal hemorrhage and for lessening the morbidity and mortality of open repair.

Aged↗
PubMed1998

Compression ultrasonography for false femoral artery aneurysms: hypocoagulability is a cause of failure.

OBJECTIVES: False femoral artery aneurysm is an occasional complication of percutaneous cardiovascular radiological procedures. Compression ultrasonography causes thrombosis non-invasively, reducing need for operative intervention. The technique fails in a proportion of cases. Analysis was undertaken to identify causes of failure. DESIGN: Prospective open study. MATERIALS AND METHODS: Patients presenting with false femoral artery aneurysm since 1984 were identified from a computerised database (BIPAS). Since 1993 compression ultrasonography has been performed as first line treatment according to a standard protocol. Prospectively collected ultrasonographic data and case notes were reviewed to identify causes of failed compression. RESULTS: False femoral artery aneurysm occurred as a complication in 32/26,687 (0.12%) cardiovascular radiological procedures. Eighteen aneurysms were treated by compression. The technique was successful in 11/18 (61%) cases but primary failure occurred in seven cases. Six out of seven had bleeding abnormalities (Chi-squared analysis with Yates correction 10.55, p = 0.0012), four were anticoagulated and compression was subsequently successful following reversal of warfarin therapy in three of these patients. In 4/18 cases surgical repair was necessary. CONCLUSION: Compression ultrasonography is an effective treatment of false femoral aneurysms, however, hypocoagulability is a significant cause of failure. For patients in whom anticoagulation cannot be reversed, primary surgical repair should be considered.

Aneurysm, False↗
PubMed1998

Cognitive testing in patients undergoing carotid endarterectomy.

OBJECTIVES: To determine by literature review the effect of carotid endarterectomy (CEA) as a modulator of cognitive function in patients with carotid arterial disease. Derive recommendations for standardising cognitive testing of patients with carotid arterial disease. DESIGN AND METHODS: The English language literature was interrogated using a CD-ROM driven medline search using carotid endarterectomy and cognitive function as keywords between 1986-1995. These subsets were scanned and papers of direct relevance or commonality were selected. Cited papers prior to 1986 from these references were then sought directly. RESULTS: There are few controlled studies reporting on the effect of CEA. There is no consensus in the literature for the effect of CEA on cognition or which tests should be used. Studies reporting a benefit for CEA lack a control group and fail to eliminate the effect of practice. Reports suggesting cognitive impairment following CEA performed follow-up tests early. CONCLUSIONS: There are many methodological problems with the study of cognitive function before and after carotid endarterectomy and wide disagreement in the interpretation of results. Further studies should contain control groups, use tests resistant to practice and be performed when the effects of surgery and anaesthesia are passed.

Cognition↗
PubMed1998

Sympathetic skin response and patient satisfaction on long-term follow-up after thoracoscopic sympathectomy for hyperhidrosis.

OBJECTIVES: To determine effect of sympathectomy for hyperhidrosis on sympathetic skin response (SSR) during long-term follow-up. Patient satisfaction was assessed and surgical complications noted. DESIGN: Prospective, Open, Non-randomised study. MATERIALS AND METHODS: Patients who had undergone bilateral thoracoscopic sympathectomy for hyperhidrosis underwent postoperative assessment of SSRs. A 15 mA stimulus was applied over the median nerve contralateral to the sympathectomy and evoked electrodermal activity was recorded from the sympathectomised palm using a Dantec Counterpoint Mk 2. Patient satisfaction with surgery was assessed by questionnaire and visual analogue score (0-1.0). RESULTS: Of 26 patients, 21 were female. Mean (range) age was 23 (9-36) years. Mean (range) follow up was 39 (4-138) months. 12% of cases had residual or recurrent symptoms. Median (range) patient satisfaction was 0.83 (0.06-1.0). In 7/52 palms recurrent SSRs were not detected. Repeated measures analysis of variance found amplitude of SSR to be of low significance with respect to time since surgery (F = 0.48; p = 0.49) and incidence of compensatory sweating (F = 2.38; p = 0.14). CONCLUSION: Thoracoscopic sympathectomy for hyperhidrosis is an effective procedure. Following sympathectomy SSRs are not permanently abolished, but return of SSRs does not correspond with symptom recurrence. As such, SSRs are a poor tool for objective assessment of long-term outcome following sympathectomy.

Adolescent↗
PubMed1998

The progression and correction of duplex detected velocity shifts in angiographically normal vein grafts.

OBJECTIVES: To review the sensitivity of duplex scanning and angiography at detecting vein graft stenoses in patients on a graft surveillance programme. DESIGN: Prospective, open, non-randomised study. PATIENTS AND METHODS: Since February 1993, 143 patients with 148 grafts (70% in situ, 30% reversed) have attended postoperative infrainguinal vein graft surveillance for a minimum of 6 weeks. Fifty-seven graft stenoses in 57 grafts were identified by duplex scanning as a localised high velocity jet. Angiography was performed in all except 12 patients. RESULTS: Angiography confirmed a duplex abnormality in all but 10 patients. Of these, five patients remain stable and asymptomatic with a persisting duplex abnormality. The remaining five patients, although asymptomatic, exhibited disease progression on duplex and surgical intervention confirmed significant stenoses, which were successfully treated. CONCLUSION: The results suggest that duplex scanning is a reliable imaging modality for detecting vein graft stenoses. Selection for surgical correction can be made, in some circumstances on the basis of clinical and ultrasound criteria alone.

Adult↗
PubMed1998

Unilateral asymptomatic carotid disease does not require surgery.

BACKGROUND AND PURPOSE: The efficacy of carotid endarterectomy (CEA) in symptomatic patients with > 70% stenosis is accepted. The stroke risk of asymptomatic patients may not justify surgical intervention. The aim of this study is to use natural history data from a single unit to identify asymptomatic patients who would benefit from CEA. METHODS: Five hundred and sixty-four patients attending for duplex ultrasound assessment of the internal carotid artery between 1986 and 1993 were retrospectively identified as focally asymptomatic with > 40% ipsilateral stenosis. Patients were traced using hospital records, family practitioner databases and the Office of Population of Census and Surveys. The number of strokes, transient ischaemic attacks and cause of death were determined. Exclusions were 15 (2.7%) asymptomatic occlusions and 49 patients (8.7%) who underwent surgery for asymptomatic disease. RESULTS: Thirteen patients (2.6%) were not traced, leaving 487 study patients. The average follow-up was 41 months (range, 1-120 months). Mean presentation age was 69 years (S.D. 8.9), and the male to female ratio was 3:2. One hundred and fifty-six (32%) patients died. Forty-three patients suffered strokes, of whom two had bilateral strokes. In total there were 16 (i/p) strokes, 25 (c/l) strokes and four strokes undetermined. The average yearly stroke rate was 2.74 per 100 person years and the (i/p) rate 1.02 per hundred person years. There was no effect of age, sex or degree of stenosis on stroke. The presence of bilateral disease did increase the risk of stroke (rel risk 2.35, p = 0.029) but not ipsilateral stroke (rel risk 1.6, p = 0.39). Patients with unilateral asymptomatic carotid disease had an all stroke rate of less than 5% in the first year after presentation and this was unaffected by degree of stenosis. In patients with bilateral disease the stroke rate in the first year after presentation increased with degree of stenosis to a stroke rate of 9.6 per 100 person years in patients with > 90% contralateral stenosis. CONCLUSIONS: This data suggests that CEA will not benefit patients with unilateral asymptomatic disease. Patients with bilateral disease warrant inclusion in clinical trials.

Aged↗
PubMed1997

Activated protein C resistance, factor V Leiden and peripheral vascular disease.

Activated protein C resistance caused by factor V Leiden is an important thrombophilia disorder which predisposes to venous thromboembolism. Some studies also suggest a role in the pathogenesis of arterial thrombosis and atherosclerosis. The authors have investigated the prevalence of activated protein C resistance and factor V Leiden in a series of 45 patients with peripheral vascular disease. Twelve patients were receiving warfarin. The activated protein C resistance ratios were significantly lower in the group of 33 non-warfarinized patients with peripheral vascular disease (median 2.82 (range 1.36-3.83)) compared with 33 age- and sex-matched controls (median 2.97 range 2.24-4.11); P<0.005; Wilcoxon rank sum). Eight patients (24%) had activated protein C resistance (ratio <2.2). The prevalence of factor V Leiden in patients with peripheral vascular disease was 17.8% (8/45). This is significantly increased compared with the local population and UK published frequency of 3.5% for this genotype. The presence of factor V Leiden did not affect the late outcome of arterial reconstructive surgery in terms of graft patency (P=0.5, Fisher's Exact test).

Aged↗
PubMed1997

Computerised audit of carotid endarterectomy: audit loopholes closed?

The number of carotid endarterectomies being performed in the UK is increasing. The role of carotid endarterectomy (CEA) in the prevention of stroke depends on the procedure being associated with as few operative strokes as possible. Good clinical practice, with minimum morbidity, depends upon the integration of recent advances. Continuing audit has been used to examine changes in surgical practice and in case mix. There was a combined death and permanent stroke rate of 3.6% after 333 CEAs in a 6-year period (1990-1995) compared with 4.4% in 203 CEAs in an earlier 5-year audit period (1985-1989). The impact of an increase in the number of operations performed after recovered strokes, those performed by trainees and the use of prosthetic patches on the results of CEA has been assessed. Specific areas to be targeted in future audits are identified.

Adult↗