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P T McCollum

Publications and source records attributed to P T McCollum.

At least 19 recordsLinked to original sources
PubMed2006

A non-randomised controlled trial of the clinical and cost effectiveness of a Supervised Exercise Programme for claudication.

OBJECTIVES: The main aims of treatment in patients with intermittent claudication (IC) are to improve the clinical indicators of lower limb ischaemia and patients' quality of life (QoL). The aims of this study were assess the clinical and cost effectiveness of a supervised exercise programme (SEP) in patients with IC. DESIGN: Non-randomised, controlled trial. SETTING: University teaching hospital. PATIENTS AND METHODS: Two groups of patients with IC were studied. Seventy patients were sequentially recruited before and after the establishment of a Supervised Exercise Programme at our unit. Thirty-seven patients (median age 69 years, 26 men) received conservative medical therapy (CMT) and 33 patients (median age 67 years, 22 men) received CMT plus a 3 month SEP of graduated physical exercise for sixty minutes, three times each week. Patients were assessed prior to and at 6 months following treatment. At each assessment patient reported walking distances (PRWD), treadmill claudication and maximal distances (ICD and MWD), ankle brachial pressure indices (ABPI) pre & post exercise and patient reported QoL using the SF36 questionnaire were assessed. RESULTS: Prior to intervention the two groups were well matched. Following treatment, CMT patients demonstrated no significant change in PRWD or ICD but did record a small but significant improvement in MWD. CMT was also associated with a negative effect size in the SF36 index and in 7 of the 8 SF36 QoL domains, effect size >-0.5 for the domains of Physical Function and Emotional Role. SEP patients demonstrated significant improvement in PRWD, ICD and MWD. SEP was associated with a positive effect size in the SF36 index and in 2 SF36 QoL domains but a negative effect size in a further 2 domains. However, all QoL effect sizes following SEP were < +/-0.5. Intergroup differences in effect sizes were >0.5 for the SF36 domains of Physical Function, Physical Role, Emotion Role and SF36 index. SEP resulted in a 0.027 quality adjusted life year (QALY) gain over CMT in the first year post-treatment thus the cost/QALY gained of SEP is pound1780 at 1 year. CONCLUSIONS: Compared to CMT, SEP increases walking distances, improves QoL and is a highly cost-effective treatment for IC.

Aged↗
PubMed2005

Heat shock proteins in vascular disease--a review.

INTRODUCTION: There is growing evidence that heat shock proteins (HSPs), a family of stress-inducible proteins may be involved in the pathogenesis of atherosclerotic vascular diseases. Here, we systematically review the evidence behind this notion. METHODS: A detailed literature search and extensive bibliographic review of literature relating to HSPs and atherosclerotic vascular disease. RESULTS: Atherosclerotic vascular disease is classified into four main areas of presentation: carotid, coronary, aortic and peripheral vascular disease, for consideration in this review. In each of these vascular diseases, the evidence linking HSPs and atherosclerosis is outlined in a systematic manner. Current evidence suggests that components of the immune system may be involved in the pathogenesis of atherosclerosis, with HSPs acting as auto-antigens in the immune response. HSPs are detected in atherosclerotic lesions and antibodies to HSPs are increased in patients with vascular disease; the rise often correlating with the severity of atherosclerosis. The levels of anti-HSP antibodies have been shown to be independent predictors of risk and have prognostic value. CONCLUSION: There is a strong link between heat shock protein expression and the principal manifestations of atherosclerotic vascular diseases. A better understanding of this involvement could lead to the development of new and improved treatment strategies.

Aortic Diseases↗
PubMed2004

The value of abdominal examination in the diagnosis of abdominal aortic aneurysm.

BACKGROUND: There is considerable variability in the reported value of clinical examination in the diagnosis of abdominal aortic aneurysms (AAA). This study aims to assess accuracy of abdominal examination by a doctor, a nurse and the patient in the diagnosis of AAA and whether this accuracy is related to the size of the aneurysm and/or the BMI of the patient. METHODS: 164 patients, 138 men and 26 women, median age 71 years, consented to participate in this prospective, single blind, controlled study. Thirty-nine patients attending for carotid duplex were used as controls. Abdominal examination was performed by a doctor and a nurse. Patients then performed self-examination. RESULTS: Examination by a doctor, a nurse and the patient were similar in accuracy in diagnosing/excluding AAA which was directly related to AAA size and patient BMI. The Negative Predicted Value of abdominal examination exceeds 0.9 with AAA diameters > or =4 cm and the Positive Predictive Value exceeds 0.8 with AAA diameters > or =5 cm. CONCLUSIONS: Abdominal examination by a doctor, a nurse and the patient is of value in the exclusion and diagnosis of significant AAA. It should be promoted and may represent a useful adjunct to population screening with ultrasound.

Aged↗
PubMed2004

A comparative study of aortic wall stress using finite element analysis for ruptured and non-ruptured abdominal aortic aneurysms.

BACKGROUND: The decision to repair an asymptomatic abdominal aortic aneurysm (AAA) is currently based on diameter (> or =5.5 cm) alone. However, aneurysms less than 5.5 cm do rupture while some reach greater than 5.5 cm without rupturing. Hence the need to predict the risk of rupture on an individual patient basis is important. This study aims to calculate and compare wall stress in ruptured and non-ruptured AAA. METHODS: The 3D geometries of AAA were derived from CT scans of 27 patients (12 ruptured and 15 non-ruptured). AAA geometry, systolic blood pressure and literature derived material properties, were utilised to calculate wall stress for individual AAA using finite element analysis. RESULTS: Peak wall stress was significantly higher in the ruptured AAA (mean 1.02 MPa) than the non-ruptured AAA (mean 0.62 MPa). In patients with an identifiable site of rupture on CT scan, the area of peak wall stress correlated with rupture site. CONCLUSIONS: Peak wall stress can be calculated from routinely performed CT scans and may be a better predictor of risk of rupture than AAA diameter on an individual patient basis.

Aged↗
PubMed2003

Fluvastatin induces apoptosis of vascular endothelial cells: blockade by glucocorticoids.

Statins block de novo synthesis of cholesterol by inhibiting the enzyme, HMG CoA reductase. The product of this reaction, mevalonic acid, is also a precursor of isoprenoids, molecules required for the activation of signaling G-proteins, such as Ras. Signal transduction pathways involving Ras are important for cell survival and this may be why statins induce apoptotic death of several cell types. Given that statins are used to treat vascular disease, surprisingly no studies have been conducted on vascular endothelial cells. Here we show that fluvastatin (FS), at concentrations from 1-2 microM, blocks growth and induces apoptosis of the endothelial cell line, EA.hy 926. Considerable redundancy is known to exist in cell signaling and in vivo toxicity of FS might be prevented by other signaling pathways, like those activated by adrenal or sex steroids. RT-PCR analysis revealed the expression of the androgen and glucocorticoid receptor in EA.hy 926 cells. Although the androgen, dihydrotestesterone (DHT) had no effect, the glucocorticoid, dexamethasone (Dex), blocked FS-induced apoptosis. Cell cycle analysis revealed that 24 h exposure to FS prevented cells from leaving G(1) and 24-48 h later a marked sub-G(1) peak was observed. Dex was able to reduce the sub-G(1) peak, but it failed to block accumulation of cells in G(1), indicating that it's effect was specific for blockade of apoptosis, and not specific to an effect on FS alone. This study strongly suggests that glucocorticoids have a role to play in preventing vascular injury and they may provide the reason why statins are not inherently toxic to vascular endothelial cells, in vivo.

Anticholesteremic Agents↗
PubMed2003

The role of hyperbaric oxygen therapy in ischaemic diabetic lower extremity ulcers: a double-blind randomised-controlled trial.

OBJECTIVE: ischaemic lower-extremity ulcers in the diabetic population are a source of major concern because of the associated high risk of limb-threatening complications. The aim of this study was to evaluate the role of hyperbaric oxygen in the management of these ulcers. METHOD: eighteen diabetic patients with ischaemic, non-healing lower-extremity ulcers were recruited in a double-blind study. Patients were randomly assigned either to receive 100% oxygen (treatment group) or air (control group), at 2.4 atmospheres of absolute pressure for 90 min daily (total of 30 treatments). RESULTS: healing with complete epithelialisation was achieved in five out of eight ulcers in the treatment group compared to one out of eight ulcers in the control group. The median decrease of the wound areas in the treatment group was 100% and in the control group was 52% (p=0.027). Cost-effectiveness analysis has shown that despite the extra cost involved in using hyperbaric oxygen, there was a potential saving in the total cost of treatment for each patient during the study. CONCLUSION: hyperbaric oxygen enhanced the healing of ischaemic, non-healing diabetic leg ulcers and may be used as a valuable adjunct to conventional therapy when reconstructive surgery is not possible.

Aged↗
PubMed2002

POSSUM and P-POSSUM overpredict mortality for carotid endarterectomy.

OBJECTIVES: the aim was to test the predictive accuracy of POSSUM and P-POSSUM on patients undergoing CEA. DESIGN: retrospective and prospective study. MATERIALS: 499 CEAs performed by four vascular surgeons from a single unit from 1992-99. The median age was 68 (range 38-86) and 60% were men. METHODS: physiological parameters, operative parameters and the 30-day mortality were collected. Predicted mortality for each patient was calculated using POSSUM and P-POSSUM equations. Patients were stratified into risk groups and observed and predicted deaths were compared. Accuracy of the prediction was assessed using chi-squared analysis. RESULTS: the observed 30-day mortality was 1.8% (9/499). The predicted deaths using POSSUM and P-POSSUM analysis were 49 and 25 respectively compared to nine observed deaths. There was significant evidence of lack of fit of both models in predicting mortality (chi-squared analysis, p<0.05). CONCLUSIONS: POSSUM and P-POSSUM overpredict mortality and are unsuitable for comparative audit of CEA. Models developed specific for CEA might accurately predict mortality.

Adult↗
PubMed2002

A Bayesian hierarchical approach to comparative audit for carotid surgery.

OBJECTIVES: the aim of this study was to illustrate how a Bayesian hierarchical modelling approach can aid the reliable comparison of outcome rates between surgeons. DESIGN: retrospective analysis of prospective and retrospective data. MATERIALS: binary outcome data (death/stroke within 30 days), together with information on 15 possible risk factors specific for CEA were available on 836 CEAs performed by four vascular surgeons from 1992-99. The median patient age was 68 (range 38-86) years and 60% were men. METHODS: the model was developed using the WinBUGS software. After adjusting for patient-level risk factors, a cross-validatory approach was adopted to identify "divergent" performance. A ranking exercise was also carried out. RESULTS: the overall observed 30-day stroke/death rate was 3.9% (33/836). The model found diabetes, stroke and heart disease to be significant risk factors. There was no significant difference between the predicted and observed outcome rates for any surgeon (Bayesian p -value>0.05). Each surgeon had a median rank of 3 with associated 95% CI 1.0-5.0, despite the variability of observed stroke/death rate from 2.9-4.4%. After risk adjustment, there was very little residual between-surgeon variability in outcome rate. CONCLUSIONS: Bayesian hierarchical models can help to accurately quantify the uncertainty associated with surgeons' performance and rank.

Adult↗
PubMed2002

Statin-induced apoptosis of vascular endothelial cells is blocked by dexamethasone.

Statins block de novo synthesis of cholesterol by inhibiting the enzyme, HMG CoA reductase. The product of this reaction, mevalonic acid, is also a precursor of isoprenoids, molecules required for the activation of signalling G-proteins, such as Ras. Signal transduction pathways involving Ras are important for cell survival and this may be why statins induce apoptotic death of several cell types. Given that statins are used to treat vascular disease, it is surprising that no studies have been conducted on vascular endothelial cells. For this reason, we have tested the effect of fluvastatin (FS) on the endothelial cell line EA.hy 926. Here we show that FS, at concentrations from 1 to 2 microM, blocks growth and induces apoptosis of the endothelial cell line, EA.hy 926. As considerable redundancy exists in cell signalling pathways for cell survival, toxicity of FS under more physiological conditions might be prevented by pathways that do not require Ras, such as those activated by adrenal or sex steroids. To test this hypothesis, first RT-PCR analysis was performed for nuclear receptor mRNA expression. This revealed the presence of mRNA for the androgen receptor (AR) and glucocorticoid receptor (GR). The effect of the AR agonist, dihydrotestosterone (DHT), and the GR agonist, dexamethasone (Dex), was then tested. Whilst DHT (100 nM) had no effect on FS-induced cell death, Dex (1 microM) blocked FS-induced apoptosis. Cell cycle analysis revealed that 24 h exposure to FS prevented cells from leaving G(1) and 24-48 h later a marked sub-G(1) peak was observed. Dex was able to reduce the sub-G(1) peak, but it failed to reduce accumulation of cells in G(1). Further studies revealed that, in addition to blocking FS-induced apoptosis, Dex was able to block apoptosis of EA.hy 926 cells induced by serum deprivation, tumour necrosis factor-alpha, oxidants, DNA damage and mitochondrial disruption. This study strongly suggests that glucocorticoids have a role to play in preventing vascular injury and they may provide a reason why statins are apparently not toxic to vascular endothelial cells in vivo.

Androgen Receptor Antagonists↗
PubMed2001

Risk modelling study for carotid endarterectomy.

BACKGROUND: The aims of this study were to identify factors that influence the risk of stroke or death following carotid endarterectomy (CEA) and to develop a model to aid in comparative audit of vascular surgeons and units. METHODS: A series of 839 CEAs performed by four vascular surgeons between 1992 and 1999 was analysed. Multiple logistic regression analysis was used to model the effect of 15 possible risk factors on the 30-day risk of stroke or death. Outcome was compared for four surgeons and two units after adjustment for the significant risk factors. RESULTS: The overall 30-day stroke or death rate was 3.9 per cent (29 of 741). Heart disease, diabetes and stroke were significant risk factors. The 30-day predicted stroke or death rates increased with increasing risk scores. The observed 30-day stroke or death rate was 3.9 per cent for both vascular units and varied from 3.0 to 4.2 per cent for the four vascular surgeons. Differences in the outcomes between the surgeons and vascular units did not reach statistical significance after risk adjustment. CONCLUSION: Diabetes, heart disease and stroke are significant risk factors for stroke or death following CEA. The risk score model identified patients at higher risk and aided in comparative audit.

Adult↗
PubMed2000

Tibial and peroneal artery bypasses using polytetrafluoroethylene (PTFE) with an interposition vein cuff.

UNLABELLED: The combined results of femoro-distal bypasses using prosthetic material with vein cuffs from two separate vascular units is presented. METHOD: Over the last five years, 89 infrainguinal bypasses using polytetrafluoroethylene (PTFE) with a distal interposition vein cuff to a tibial artery have been performed in two centres. All operations were for critical limb ischaemia. The mean age was 72 years (47-90), there were 46 males and 43 females, 27 of whom were diabetic. Twenty-eight patients had a history of angina and/or previous myocardial infarct. The median follow-up was 12 months (0-68 months). RESULTS: During the follow-up period there were 28 deaths, 35 major limb amputations and 44 graft failures. The graft patency rates at 12 and 24 months were 50 and 32%, and limb salvage rates were 53 and 44%, respectively. The patient survival rates were 66 and 61%, respectively. CONCLUSION: The authors believe that the likely improvement in pain free quality of life the patient may enjoy with a successful bypass shifts the balance in some individuals towards bypass surgery using PTFE with a vein cuff to a tibial artery when such an option is possible.

Aged↗
PubMed1999

Disruption of skin perfusion following longitudinal groin incision for infrainguinal bypass surgery.

OBJECTIVE: The objective of our study was to investigate whether such an incision results in a reduction in blood flow, and therefore haemoglobin oxygen saturation, across the wound. DESIGN: Microvascular oxygenation was measured with lightguide spectrophotometry in 21 patients undergoing femoropopliteal or femorodistal bypass procedures. A series of measurements were made in the groin, medial and lateral to the surface marking of the femoral artery. The mean oxygen saturation on each side was calculated, and the contra-lateral groin was used as a control. The measurements were repeated at 2 and 7 days postop. RESULTS: Oxygen saturation in the skin of the operated groins was increased significantly from baseline at 2 days postop (f = 25.80, p < 0.001) and had begun to return to normal by day 7. The rise was more marked on the lateral side of the wound than on the medial (f = 12.32, p < 0.001). There was no such difference in the control groins. All wounds healed at 10 days. CONCLUSIONS: These results show a significant difference in skin oxygenation between the lateral and medial sides of the groin following longitudinal incision. This may contribute to the relatively high incidence of postoperative infection in these wounds.

Aged↗
PubMed1999

Audit of the effect of introducing local guidelines for referral for carotid duplex scanning.

Guidelines for referral of patients for carotid duplex scanning were introduced stating that scans were only indicated for patients with hemispheric localising symptoms or asymptomatic bruits. A 19% reduction in referral rate was seen for new scans in a one year period. The number of "inappropriate" requests fell from 27.6% in 1994 to 12.8% in 1995. There was no reduction in the numbers of patients identified with effectively occult asymptomatic disease who may have been suitable for surgery in the same period. Guideline introduction had the effect of reducing unnecessary scans without any effect on the overall pick-up, rate for carotid disease.

Carotid Stenosis↗
PubMed1999

Accuracy of the recording of operative events by the Scottish Morbidity Record 1 (SMR1) for a teaching hospital vascular unit.

OBJECTIVE: To determine the accuracy of operative data collected for the Scottish Morbidity Record 1 (SMR1). DESIGN: Retrospective comparative analysis of operative data recorded by the Scottish Office Information and Statistics Division (ISD) with that recorded in a locally held vascular database where the clinical information was entered by medical personnel. SUBJECTS: All patients with a codeable operative procedure carried out under the care of a single consultant vascular surgeon in a Regional Vascular Unit in 1994. RESULTS: A total of 840 admissions involving at least one OPCS4 code were recorded in the Vascular Database and 793 by the Scottish Office ISD. Although there was good agreement of the total number of operations and admissions, operative codes for 23 patients undergoing major abdominal aortic surgery and 19 undergoing major limb reconstruction were not recorded by the ISD. This represents 14% of total major arterial reconstructions in a single year. CONCLUSION: Accurate data collection has wide implications for research, monitoring future health trends, and planning hospital bed numbers. SMR1 data may accurately record total number of admissions and operations but is poor at distinguishing between those admissions that may be resource-intensive.

Cardiovascular Surgical Procedures↗
PubMed1998

Management of iliac occlusions with a new self-expanding endovascular stent.

OBJECTIVES: To determine the patency and acceptability of the Memotherm endovascular stent in the treatment of iliac arterial occlusions. MATERIALS AND METHODS: Twenty-two patients (12 males and 10 females) underwent stenting of iliac occlusions of the aortoiliac bifurcation, the common iliac artery and the external iliac artery. All patients were reassessed at 3, 6 and 12 month intervals and then yearly to evaluate their symptoms and Doppler pressure measurements. Comparison was made with results from other studies treating iliac occlusions by angioplasty alone or combined with stenting. RESULTS: Out of 22 patients, 21 had an immediate and sustained improvement over the whole of the follow-up period. The Ankle-brachial Index (ABI) increased from a mean value of 0.49 to 0.81 3-months postprocedure and improved to 0.85 at 12 months (paired t-test p < 0.001). At 6 and 12 months the stent patency remained at 95.5%, which compares favourably with other studies. There were four minor and one major complication associated with the stenting procedure. CONCLUSIONS: The Memothern self-expanding stent is a useful, safe and effective device suitable for the majority of iliac occlusions. Further long-term evaluation is warranted to confirm its advantages over open surgery.

Aged↗