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Biomedical subjects

P A Stonebridge

Publications and source records attributed to P A Stonebridge.

At least 19 recordsLinked to original sources
PubMed2001

Antiplatelet and anticoagulant therapy to prevent bypass graft thrombosis in patients with lower extremity arterial occlusive disease.

The incidence of graft failure for above knee femoropopliteal grafts is described by the European Consensus Document on Critical Limb Ischaemia. It occurs in approximately 15% of patients when vein is used for the grafting procedure and in 20% of patients when PTFA (polytetrafluoroethylene) or other prosthetic material is used. Femorodistal grafts have a much poorer outcome with 45% and 75% failure rates for vein and prosthetic grafts, respectively. Prevention of primary graft failure and thus the need for surgical reintervention is of major clinical and economic importance. Early failure, occurring within one month of operation, is usually due to technical error such as poor patient selection or operative technique. Approximately 10% of graft failures will fall into this time period. When grafts thrombose after two years, progression of native atherosclerosis either proximally or distally is the usual cause. This accounts for 2-3% of all graft failures each year. The most common time for grafts to fail is between one month and two years (80% of all failures) and this is the same period in which graft stenoses are now known to develop. There are few evidence-based recommendations for the use of pharmacological agents in maintaining graft patency following peripheral vascular surgery. This article reviews the evidence for or against the use of anticoagulant and antiplatelet therapy for the prevention of bypass graft thrombosis in patients with peripheral arterial occlusive disease.

Anticoagulants↗
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↗
PubMed2000

Elevated levels of soluble E-selectin in diabetic patients with severe symptomatic peripheral arterial occlusive disease requiring angioplasty. A possible role in diabetic vascular disease?

BACKGROUND: To study levels of E-selectin in patients with peripheral arterial occlusive disease who were undergoing percutaneous transluminal angioplasty. METHODS: Experimental design and setting: Cross sectional case control study, conducted in a teaching hospital. SUBJECTS: Seven patients with type-2 (non-insulin dependent) diabetes mellitus undergoing transluminal angioplasty for symptomatic peripheral arterial occlusive disease, had blood tests for sE-selectin measurement, and were compared to a similar groups of age and sex matched non-diabetic patients with arteriopathy who are undergoing the same procedure. Also evaluated were a group of diabetic patients and healthy non-diabetics with no peripheral arterial disease. RESULTS: The levels of sE-selectin in the two diabetic groups were significantly higher than the non-diabetic groups measuring at 77 ng/ml (53-120) and 79 ng/ml (43-98) (median, range) vs 54 ng/ml (24-104) in the non-diabetic with arteriopathy, and 42 ng/ml (35-66) in the normal healthy controls, p<0.04, p<0.003 respectively, Mann Whitney "U" test. CONCLUSIONS: We have demonstrated significantly high values of soluble E-selectin in patients with diabetes mellitus requiring angioplasty for symptomatic peripheral arterial occlusive disease. This suggests that sE-selectin may be involved in the diabetic angiopathic process. It may act as a precursor for smooth muscle proliferation.

Angioplasty, Balloon↗
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

Interleukin-8 (IL-8) may contribute to the activation of neutrophils in patients with peripheral arterial occlusive disease (PAOD).

OBJECTIVES: to investigate the levels of interleukin-8 (IL-8) in patients with peripheral arterial occlusive disease (PAOD) and healthy control subjects both before and after an acute exercise test. MATERIALS AND METHODS: twenty-six patients with intermittent claudication and 22 matched healthy control subjects each had IL-8 levels measured before and after a standard acute treadmill-exercise test. Subjects walked for 10 min or until stopped by claudication pain. Serum IL-8 levels were measured before exercise was commenced and 1, 5 and 10 min after exercise was stopped. RESULTS: patients with PAOD had statistically significantly higher levels of IL-8 than healthy control subjects, before and after an acute exercise test (p <0.00001, Mann-Whitney). Ratios of the change of IL-8 levels post-exercise showed a statistically significant difference at the post-5-min time point (p =0.005), showing a difference in the change of IL-8 levels at this time point between the patient group and control group. CONCLUSIONS: The increased levels and the failure of the cytokine levels to fall by the same extent after exercise in the patient group may be due to a combination of increased neutrophil activation, reduced blood flow and increased cytokine production during ischaemia-reperfusion, which is not observed in the healthy controls.

Adult↗
PubMed1999

Decrease in P-selectin levels in patients with hypercholesterolaemia and peripheral arterial occlusive disease after lipid-lowering treatment.

At sites of thrombosis and vascular injury, interactions occur among platelets, leucocytes and endothelial cells. Patients with peripheral arterial occlusive disease (PAOD) have been shown to have raised total serum cholesterol and serum triglycerides and increased sP-selectin levels when compared with controls. A total of 31 patients with PAOD and hypercholesterolaemia took part in this three-staged study. Soluble P-selectin (sP-selectin) levels were significantly lowered after 12 weeks of fluvastatin treatment (157.0 ng/ml versus 113.77 ng/ml, p = 0.01), whereas 12 weeks of placebo treatment had no statistically significant effect on sP-selectin levels (150.0 ng/ml versus 139.4 ng/ml). An unpaired t-test almost reached statistical significance (p = 0.051) when the levels by which sP-selectin fell after 12 weeks of active or placebo treatment were compared. The placebo group was then put onto long-term, active treatment and sP-selectin levels were significantly lowered by fluvastatin when compared to pre-treatment levels (150.0 ng/ml versus 110.0 ng/ml, p = 0.03). By lowering the levels of P-selectin, fluvastatin may not only attenuate atherosclerotic progression but may also decrease the platelet activation associated with PAOD.

Aged↗
PubMed1999

Lipid-lowering and skin vascular responses in patients with hypercholesterolaemia and peripheral arterial obstructive disease.

Elevated blood cholesterol is a major risk factor for atherosclerosis. Recent studies show that lowering cholesterol reduces the risk of vascular disease, but the precise mechanisms for vascular improvement are not fully understood. Furthermore, it is not known whether the beneficial effects of cholesterol lowering extend to the skin microvasculature. In this unrandomized, open design study, we used iontophoresis and laser Doppler flowmetry to examine forearm skin perfusion in hypercholesterolaemic patients with PAOD before and after cholesterol-lowering therapy with fluvastatin. Endothelium-dependent and -independent vasodilatation were measured following skin iontophoresis of acetylcholine (ACh) and sodium nitroprusside (SNP), respectively. Before cholesterol-lowering, vascular responses to ACh and SNP were reduced significantly in patients compared with responses in control subjects (p < 0.001 and p < 0.05, ANOVA, respectively). Fluvastatin therapy (40 mg/day) for 24 weeks significantly reduced total cholesterol (7.3+/-0.3 to 6.0+/-0.2 mmol/l, p < 0.001) and LDL cholesterol (5.4+/-0.5 to 4.2+/-0.4 mmol/l, p < 0.01). Vasodilatation to SNP was significantly improved at week 24 (p < 0.05). In patients with hypercholesterolaemia and PAOD, cholesterol-lowering with statin therapy significantly improved endothelium-independent vascular responses to SNP in skin microvessels. The application of the non-invasive techniques of iontophoresis and laser Doppler flowmetry may provide useful markers for the assessment of microvascular function in this group of patients.

Acetylcholine↗
PubMed1999

Completion of the journey of care: Scottish Audit of Surgical Mortality (SASM).

The ideal must be to audit all deaths as part of routine surgical and anaesthetic practice. We have examined the level of compliance of surgeons and anaesthetists participating in the Scottish Audit of Surgical Mortality (SASM) for the audit's first three years. The audit has achieved more than 92% compliance, unchanged over a three year period. As a consequence it can be regarded as a truly routine part of surgical and anaesthetic practice within Scotland.

Data Collection↗
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↗
PubMed1998

Minimizing the risk of penetrating injury to surgical staff in the operating theatre: towards sharp-free surgery.

Conventional surgery carries a significant risk of inadvertent injury to members of the scrub team. Although minor injury is common and usually no more than unpleasant, serious consequences may occur. Modifications in technique together with the application of modern instrumentation may reduce the risks of sharp injury substantially. The techniques and technology available in the conventional open surgery setting are reviewed.

Accidents, Occupational↗
PubMed1997

Randomized trial comparing infrainguinal polytetrafluoroethylene bypass grafting with and without vein interposition cuff at the distal anastomosis. The Joint Vascular Research Group.

PURPOSE: A multicenter randomized prospective study was undertaken to determine whether an interposition vein cuff improved the short-term and medium-term patency and limb salvage rates of femoral-above-knee and femoral-below-knee popliteal artery polytetrafluoroethylene (PTFE) bypass procedures. METHODS: Two hundred sixty-one bypass operations were randomized (133 to vein cuff and 128 to no vein cuff). One hundred fifty grafts were to the above-knee popliteal artery, 96 to the below-knee popliteal artery, and 15 to tibial vessels. The median follow-up was 617 days. RESULTS: The 12-month patency rates for cuffed and uncuffed above-knee popliteal artery PTFE bypass grafts were 80% and 84%, and the 2-year patency rates were 72% and 70%, respectively. The patency rates for bypass grafts to the below-knee popliteal artery at 12 months were 80% and 65% and at 2 years 52% and 29%, respectively (p = 0.03). At the below-knee site, this was reflected in 24-month difference in limb salvage rates of 84% and 62%, respectively (p = 0.08). CONCLUSIONS: There was no improvement in the patency rate with the use of a distal anastomosis interposition vein cuff in femoral-above-knee popliteal PTFE bypass grafts, but there was a statistically significant advantage when PTFE bypass grafts were anastomosed to the popliteal artery below the knee.

Aged↗
PubMed1996

What are the indications for a carotid duplex scan?

Carotid duplex scanning offers a quick and non-invasive method for detecting extracranial carotid arterial disease. However, the increasing awareness of the association of carotid disease and cerebrovascular symptoms, together with the recognition that carotid endarterectomy offers the possibility of prevention of a major stroke [1], means that requests for investigation are constantly increasing. The Dundee Vascular Laboratory undertakes the majority of carotid duplex scans in the Tayside region and we have found an increasing burden is being placed on a limited resource that is required for other vascular investigations. In 1994 we carried out 1389 carotid examinations of which 929 (66.9%) showed either no abnormality or no more than a 50% stenosis in one vessel. More importantly, of the 1052 new requests 832 (79.1%) fell into the same category. In order to ascertain if the number of new requests could be reduced a retrospective analysis of the referral indications for a carotid duplex scan in the last 5 years has been undertaken.

Adolescent↗
PubMed1996

Growth rate of infrarenal aortic aneurysms.

OBJECTIVE: To delineate the natural history of infrarenal aortic aneurysms with respect to growth rate. METHODS: A referral based series of 233 patients with abdominal aortic aneurysm was serially assessed by abdominal ultrasound. RESULTS: The mean age was 71 years and the median follow up 26 months (range 6-146). The mean growth rate of the series was 3.2mm/year. Division of the initial size into those less than 41 mm (128 patients), between 41-60 mm (92 patients) and those above 60 mm (13 patients) in AP diameter showed mean growth rates per year were 2.6 mm/year, 4.1 mm/year and 6.5 mm/year. Examination of the relationship between aneurysm size and subsequent growth rate over the whole study period revealed a rank correlation of 0.19 (p = 0.002). Aneurysms were also observed to expand at an erratic rate both in terms of time and size. CONCLUSIONS: When the initial decision is to observe the patient, serial ultrasound examinations facilitate later judgements on the balance of risks in relation to surgical treatment.

Adult↗
PubMed1996

Spiral laminar flow in vivo.

1. Blood flow patterns are poorly understood despite their impact on arterial disease. There have been few measurements in vivo of the three-dimensional blood flow patterns; we present the results of such studies using a new non-invasive in-vivo method of examining biplanar arterial blood flow patterns. 2. Multiple colour Doppler ultrasound directional velocity images were obtained at two different beam target angles from the artery in the plane perpendicular to its axis. Ensemble average images were constructed; the absolute velocity and direction were calculated by compounding the left and right averaged images. Simple directional, non-directional velocity and vector maps were constructed. 3. Flow patterns were sampled in 11 healthy male volunteers at four points of the pulse cycle; peak systole, systolic downswing, diastolic reverse flow and diastolic forward flow and at three sites; the right common and distal superficial femoral and the left common femoral arteries. 4. Stable rotational flow was observed in all subjects, the direction of rotation varying between sides and individuals. 5. There are theoretical advantages to spiral laminar blood flow; the forward-directed, rotationally induced stability and reduction of laterally directed forces may reduce turbulence in the tapering branching arterial tree and at stenoses and have a beneficial effect on mechanisms of endothelial damage and repair.

Blood Flow Velocity↗
PubMed1996

Prognosis of elderly patients with non-specific abdominal pain.

OBJECTIVE: To examine the long term outcome of patients over 65 years presenting with acute non-specific abdominal pain. SETTING: District general hospital. DESIGN: Retrospective cohort survey. SUBJECTS: 43 patients with non-specific abdominal pain, median age 75.5 years, presenting in 1985. METHODS: Case notes were reviewed and a questionnaire sent to the patients' general practitioners to assess long term outcome. RESULTS: There was little evidence that these patients subsequently developed or died from a disease requiring surgery. However, this patient group did have a significantly poorer five year survival than a representative control group because of cardiorespiratory disorders. CONCLUSIONS: Non-specific abdominal pain in elderly patients should not be regarded as harmless but may have medical rather than surgical implications.

Abdominal Pain↗