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Biomedical subjects

P M Lamont

Publications and source records attributed to P M Lamont.

At least 19 recordsLinked to original sources
PubMed2003

Reoperation for neurological complications following carotid endarterectomy.

BACKGROUND: There remains a dilemma whether or not to re-explore the carotid artery when a neurological complication occurs after carotid endarterectomy. This study reviewed the indications for, findings and clinical outcomes following re-exploration. METHODS: Patients who experienced transient or permanent neurological events following carotid endarterectomy were identified from a prospectively compiled computerized database. Case notes were retrieved to determine time to onset of symptoms, use of carotid artery imaging and details about patients who had surgical re-exploration, and outcomes. RESULTS: Some 780 consecutive carotid endarterectomies were performed over 16 years, with an incidence of major stroke or death of 2.3 per cent (18 patients). Fifty-one patients experienced transient or permanent neurological events following surgery, 25 of whom underwent re-exploration. The findings included carotid thrombosis (ten patients), flap or other technical cause (three), haematoma (two) and no abnormality (ten). The neurological outcome after 30 days was similar, whether or not the carotid artery was re-explored. CONCLUSION: Carotid artery re-exploration was undertaken in approximately half of the patients who developed neurological complications following carotid endarterectomy. Although the cause was identified and a secondary procedure was undertaken in 14 of 25 patients, there was no improvement in clinical outcome at 30 days compared with that of patients managed non-operatively.

Aged↗
PubMed2003

Risk factor documentation in elective and emergency vascular surgical admissions.

OBJECTIVES: this study investigates current practice of risk factor documentation in a vascular unit and compares variations in risk factor assessment between elective and emergency admissions. METHODS: one hundred and forty-four patients who underwent vascular surgical intervention for atherosclerotic disease during the year 2000 were retrospectively identified from computerised database. Case note review collated demographic details, data on risk factor assessment and the nature of surgery. Data were analysed using SPSS statistical software. RESULTS: the male to female ratio was 2.3:1 with a median (range) age of 73 (31-95) years. For 55 (38%) emergency admissions the following risk factors were not documented; ischaemic heart disease (8), diabetes mellitus (10), hypertension (10), smoking habit (13) and antiplatelet therapy (18). For 89 (62%) elective admissions the following risk factors were not documented; ischaemic heart disease (11), diabetes mellitus (9), hypertension (4), smoking habit (5) and antiplatelet therapy (19). Sixty-six (72.5%) routine admissions and 11 (20.8%) emergency admissions had estimations of serum cholesterol documented (chi(2) p < 0.001). There were no statistically significant differences in the documentation of other risk factors between the 2 groups. CONCLUSION: risk factors are not documented consistently for emergency vascular surgical admissions. Staff education should aim to improve risk factor assessment for elective and emergency admissions to reduce cardiovascular events and possibly improve surgical outcome in patients with atherosclerotic disease.

Adult↗
PubMed2002

A randomised, double blind, placebo-controlled study to determine the efficacy of immune modulation therapy in the treatment of patients suffering from peripheral arterial occlusive disease with intermittent claudication.

OBJECTIVES: this study examined the effect of immune modulation therapy (IMT) on claudication distances. MATERIALS AND METHODS: a double-blind placebo controlled trial was performed on patients with disabling intermittent claudication with randomisation stratified for short and long distance IC. For IMT, following exposure to UV light, oxidisation and 42.5 degrees C, 10 ml of citrated autologous blood was administered by intra-muscular injection. One course consisted of 6 injections in 3-weeks followed by 3-weeks rest. Patients received 2, 3 or 4 courses depending on response. The primary end-point was the number of responders (>50% increase in initial claudication distance (ICD)) in each group. Secondary end-points included percentage changes in ICD and change in quality of life. RESULTS: at week 24, there were more responders in the IMT group (20/31, 65%) compared to placebo (16/39, 41%) (p=0.06). In the subgroup of short distance claudicants this difference reached significance (IMT 17/26, 65%) (Placebo 12/33, 36%) (p=0.04). The median increase in ICD was significantly greater in the IMT group (81%) compared to placebo (44%, p=0.04). These results were supported by quality of life measurements. CONCLUSIONS; IMT is a safe and apparently effective treatment for patients with short distance claudication.

Aged↗
PubMed2002

Pre-operative hand-held Doppler run-off score can be used to stratify risk prior to infra-inguinal bypass surgery.

OBJECTIVES: to investigate the relationship between calf vessel run-off assessed by hand-held Doppler, graft patency and patient survival following infra-inguinal graft surgery. DESIGN: prospective cohort study of 258 consecutive patients undergoing infra-inguinal bypass grafts in one centre between 1995-99. MATERIALS AND METHODS: ankle Doppler auditory waveform characteristics were documented for patients considered for infra-inguinal bypass grafting. Doppler signals from the anterior tibial, posterior tibial and dorsalis pedis arteries were scored triphasic/biphasic (2), monophasic (1) or absent (0). A total Doppler run off score (0-6) was calculated. Following surgery graft surveillance was undertaken using duplex ultrasound at 6, 12, 26 and 52 weeks. Graft and patient survival were analysed using Cox regression analysis. RESULTS: overall primary assisted graft patency at one year was 80%. With an increasing Doppler score from 0 to 6, primary assisted graft patency steadily rose from 50% to 100% (p = 0.0002), accompanied by a steady fall in patient mortality from 50% to 5% (p = 0.0003).

Aged↗
PubMed2001

The effect of acute normovolaemic haemodilution on blood transfusion requirements in abdominal aortic aneurysm repair.

OBJECTIVE: to evaluate the impact of acute normovolaemic haemodilution (ANH) on the blood transfusion requirements in elective abdominal aortic aneurysm (AAA) repair in a single vascular unit. METHODS: thirty-two patients underwent ANH during elective AAA repair between 1992 and 1997. The operation was performed by the same surgeon/anaesthetist team in 75% of cases. Their demographic details, type of aneurysm (infra-renal or supra-renal), preoperative blood cross match, use of intra-operative red cell salvage, blood loss, peri-operative bank blood requirements, pre-op and on-discharge haemoglobin levels and post-operative outcome were recorded. The results were compared to a group of 40 randomly selected patients (to represent the unit average) who underwent elective AAA repair by variable surgeon/anaesthetist teams without ANH in the same time period. RESULTS: there were more supra-renal AAA repairs in the ANH group (8/32) than in the non-ANH group (0/40, p<0.01). ANH patients required significantly less blood transfusion peri-operatively (median 2 units) than the non-ANH patients (median 3 units, p=0.02). There were no other significant differences between the variables measured. CONCLUSION: these results suggest that a dedicated team can achieve significant reductions in the use of heterologous blood transfusion compared to the vascular unit average experience by the effective use of ANH.

Aged↗
PubMed2001

The systemic effects of intermittent claudication are reversed by angioplasty.

INTRODUCTION: exercise in patients with intermittent claudication causes systemic effects, the consequences of which are unknown. This study investigates whether successful PTA reverses the systemic effects. PATIENTS AND METHODS: ten patients with IC were recruited prior to PTA. Having emptied their bladders and rested for 1 h, pre-exercise blood and urine samples were collected. Patients underwent treadmill exercise to maximum walking time and blood samples were collected at 10, 20 and 30 min. A second urine sample was collected at 60 min. Total antioxidant capacity (TAC) and von Willebrands Factor (vWF) were measured in blood and albumin/creatinine ratio (ACR) and retinol binding protein/creatinine ratio (RBP/Cr) in urine. Patients were recalled 2 weeks after successful angioplasty and the protocol repeated. Following PTA patients walked for a maximum of 5 min. RESULTS: there was no significant change in vWF. Exercise in claudicants induced a significant increase in median ACR (pre/post exercise=0.85 p =0.03) and in median RBP/Cr (pre/post exercise=1.8 p =0.04). These changes were no longer evident after successful PTA. TAC was significantly different before and after angioplasty at all time intervals. CONCLUSION: successful PTA reverses glomerular effects of exercise in claudicants. Future work should investigate the use of PTA in conjunction with exercise in the treatment of peripheral vascular disease.

Adult↗
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↗
PubMed1999

Vascular surgical intervention for complications of cardiovascular radiology: 13 years' experience in a single centre.

This study investigates incidence and outcome of iatrogenic vascular complications needing surgery in a single vascular unit serving interventional vascular radiology and interventional cardiology. Evolution of diagnostic and interventional cardiovascular radiology, along with the introduction of non-surgical therapies for such complications, may have influenced the number of vascular complications requiring emergency surgery. Vascular surgical data were collected from information prospectively entered on computerised database and case note review. Radiology data were collated from prospective entries in logbooks and computerised database. In all 24,033 cardiovascular radiological procedures were performed between 1984 and 1996 (61% cardiac), numbers increasing annually. During this period, 62 patients (40 peripheral; 22 cardiac) required emergency surgical intervention after radiological procedures. Mean age was 61.9 years (range 1-92 years), male to female ratio was 1:1. The absolute number of cases requiring surgical intervention peaked in 1989, subsequently reducing annually. Sites of vascular injury included common femoral artery (40), brachial artery (6), iliac artery (6), popliteal artery (5), other (5). A total of 87 vascular surgical operations was performed (range 1-6 operations per patient). Interventions included thrombectomy/embolectomy (29), bypass grafting (16), direct repair (27). Seven major amputations were performed (two bilateral). Mortality after surgery was 9.7%. Mean inpatient hospital stay was 11.3 days (range 0-75 days). A Poisson regression model indicates a 5% reduction in risk for each successive year of observation; however, this did not reach statistical significance (P = 0.16, 95% CI 12% decreased risk to 2% increased risk). The risk of surgical intervention after diagnostic or interventional cardiovascular radiology is diminishing but still requires vigilance. Necessity for surgical intervention is associated with a high risk of morbidity and mortality.

Adolescent↗
PubMed1998

A phase contrast (PC) rephase/dephase sequence of magnetic resonance angiography (MRA): a new technique for imaging distal run-off in the pre-operative evaluation of peripheral vascular disease.

OBJECTIVE: To prospectively compare a 3-D phase contrast (PC) magnetic resonance angiography (MRA) sequence (rephase/dephase) with digital subtraction angiography (DSA) in pre-operative evaluation for femoropopliteal grafting in peripheral vascular disease. Assessment of distal run-off vessels and suggested siting of distal graft anastomosis to the above or below knee segment of the popliteal artery was made. METHODS: Twenty-two lower extremities booked for infra-inguinal vascular reconstruction were imaged pre-operatively using MRA and DSA. A PC rephase/dephase sequence which includes gradient motion refocusing (Siemens 1.0 T Magnetom Impact TR 50 ms, TE 14/14 ms and 15 degree flip angle) and 3-D MIP algorithm reconstruction was used to obtain the MR images. Standard techniques were used to obtain the DSA images, and the mean and median time between imaging modalities was one month. Blinded review by a consultant vascular radiologist scored nine vessel segments for each limb and assessed which popliteal arterial segment would be most suitable for distal anastomosis. RESULTS: The score from DSA and MRA agreed for 155/198 vessel segments (kappa 0.57) and the suggested siting for distal anastomosis agreed for 19/22 limbs (kappa 0.72). Eighteen limbs had surgery as planned (distal anastomosis to the above knee popliteal eight limbs, below knee popliteal 10 limbs). For three limbs the siting of the distal anastomosis suggested by DSA and MRA disagreed. The more accurate modality was proved for one of three limbs and showed MRA to be superior to DSA. CONCLUSION: Three-dimensional PC rephase/dephase MRA is a promising technique which compared well with DSA in the pre-operative assessment of distal run-off for femoropopliteal grafting.

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↗