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Biomedical subjects

J S Budd

Publications and source records attributed to J S Budd.

At least 19 recordsLinked to original sources
PubMed2003

Infrainguinal bypass graft patency and limb salvage rates in critical limb ischemia: influence of the mode of presentation.

Rest pain, ulceration, and gangrene are often considered together in studies describing outcomes in patients with critical limb ischemia. A retrospective analysis of prospectively collected data of 152 infrainguinal bypass grafts performed on 128 patients with chronic critical limb ischemia over a 6-year period was carried out. Grafts were classified according to the mode of presentation and were followed up by regular clinical and duplex examinations. Mean follow-up period was 29 months (range 12 to 60 months). Patients' demographics, risk factors, and graft characteristics were not statistically different between the groups. The 5-year cumulative primary patency rates were 33%, 52%, and 51% for gangrene, ulceration, and rest pain, respectively (p = 0.04). The 5-year cumulative primary assisted patency rates were 46%, 70%, and 72% for gangrene, ulceration, and rest pain, respectively (p = 0.01). The 5-year cumulative secondary patency rates were 48%, 76%, and 75% for gangrene, ulceration, and rest pain, respectively (p = 0.003). The 5-year cumulative limb salvage rates were 59%, 87%, and 83%, for gangrene, ulceration, and rest pain, respectively (p = 0.01). Gangrene is a distinct subcategory of critical limb ischemia with a worse prognosis than ulceration and rest pain and should be classified as such when reporting results of infrainguinal bypass grafts.

Aged↗
PubMed2001

Patient and hospital benefits of local anaesthesia for carotid endarterectomy.

OBJECTIVES: this study reviews and compares carotid endarterectomy (CEA) performed under local anaesthesia (LA) with CEA performed under general anaesthesia (GA) in a single institution. METHODS: data were collected prospectively from 240 CEA procedures. 140 GA CEA procedures are compared to 100 LA CEA procedures in terms of outcome, operative techniques, complications, and length of stay. RESULTS: the groups were similar for age, gender distribution and preoperative risk factors. There were more asymptomatic patients in the LA group. There were no significant differences in death, stroke or death/stroke rate between the two techniques. LA CEA was associated with lower shunt rate (LA 13%, GA 50%, p < 0.001), lower incidence of intraoperative hypotension (LA 8%, GA 40%, p < 0.001), decreased hospital stay (median (IQ); LA 2 (1-2), GA 3 (1-4), and a cost saving of pound235 per CEA procedure. CONCLUSIONS: carotid endarterectomy can be performed safely under local anaesthesia with the advantage that LA CEA enables the surgeon to monitor and selectively shunt patients more accurately. In addition LA CEA is associated with a shorter hospital stay and important cost savings.

Adult↗
PubMed1999

Experience with heparin-bonded collagen-coated grafts for infrainguinal bypass.

The perfect conduit for infrainguinal reconstructive surgery does not exist. When autologous vein is not available, then a prosthetic graft must be used. The use of a heparin-bonded graft has the theoretical advantage of reducing smooth muscle cell proliferation and thrombus formation, thereby reducing occlusion rates. The application of a collagen layer to the external surface of the graft serves to reduce transfabric haemorrhage. Forty-six patients underwent 47 infrainguinal reconstructions using heparin-bonded collagen-coated Dacron grafts over a 4-year period. Twenty grafts were for disabling claudication and 27 for critical ischaemia. Twenty-two grafts were to the above knee popliteal artery (47%), 10 to the below knee popliteal (21%) and 15 to one of the crural vessels (32%). There was a cumulative patency at 4 years of 69% for the above knee grafts, and 30-month patency of 58% and 45% for the below knee and crural grafts, respectively. There were three deaths over the study period and eight patients required major amputations.

Aged↗
PubMed1999

The incorporation of a stent-graft into the porcine aorta and the inflammatory response to the endoprosthesis.

The fate of a non-sutured anastomosis and the inflammatory response to an endoprosthesis in a porcine aorta was determined. Self-expanding aorto-aortic endovascular prostheses were deployed into the infrarenal aorta of Large White pigs by the transfemoral route, in accordance with Home Office regulations. Animals were followed up at intervals to 1 year. The aortas were explanted and specimens were subjected to light microscopy. Thirteen animals, mean weight 103 kg, underwent placement of a prosthesis. There was early evidence of a neointima at 4 weeks and a well-developed neointima by 12 weeks, with complete incorporation of the endoprosthesis. The early acute inflammatory reaction seen at 4 weeks had become chronic by 12 and was largely absent by 26 weeks. There was no evidence of atypia. Complete incorporation of the non-sutured anastomosis is seen in this model. The acute inflammatory reaction to the prosthesis seen at 4 weeks had largely subsided by 26 weeks.

Acute Disease↗
PubMed1999

Experimental assessment of proximal stent-graft (InterVascular) fixation in human cadaveric infrarenal aortas.

OBJECTIVES: This paper investigates the radial deformation load of an aortic endoluminal prosthesis and determines the longitudinal load required to cause migration in a human cadaveric aorta of the endoprosthesis. DESIGN AND METHODS: The endovascular prosthesis under investigation was a 24 mm diameter, nitinol, self-expanding aortoaortic device (InterVascular, Clearwater, Florida, U.S.A.). Initially, a motorised digital force gauge developed an incremental load which was applied to the ends of five stent-grafts, to a maximum of 10 mm (42%) compression. Secondly, using a simple bench model, each ends of four stent-grafts were deployed into 10 cadaveric experimental aneurysm necks and a longitudinal load applied to effect distraction. RESULTS: Increasing load produced increasing percentage deformation of the stent-grafts. The mean longitudinal distraction load for an aneurysm neck of 20 mm was 409 g (200-480 g), for 15 mm was 277 g (130-410 g) and for 10 mm was 218 g (130-340 g). The aneurysm diameter and aortic calcification had p values of 0.002 and 0.047, respectively, while the p value for aneurysm neck length was less than 0.00001. CONCLUSIONS: These results suggest that there is a theoretical advantage of oversizing an aortic prosthesis and that sufficient anchorage is achieved in an aortic neck of 10 mm to prevent migration when fully deployed.

Aorta, Abdominal↗
PubMed1999

Age-related outcome for peripheral thrombolysis.

OBJECTIVES: To investigate the age-related outcome of peripheral thrombolysis and determine for which patient group this treatment is worthwhile. DESIGN AND METHODS: A combined retrospective and prospective analysis of consecutive patients undergoing thrombolysis for acute lower-limb ischaemia was made with respect to age-related outcome and other risk factors. RESULTS: One hundred and two patients underwent thrombolysis for acute limb ischaemia. In the under 60 age group there was a 40% amputation rate. Seventy-three per cent of this group smoked. In the over 80 age group, the amputation rate was 15% and only 8% were smokers. CONCLUSION: Advancing age is not an adverse risk factor for thrombolysis which appears to be safe and effective in this patient group. There is a high incidence of smoking in the younger age group (< 60 years), in whom failed thrombolysis frequently leads to amputation.

Acute Disease↗
PubMed1996

Comparison of magnetic resonance imaging measurements of abdominal aortic aneurysms with measurements obtained by other imaging techniques and intraoperative measurements: possible implications for endovascular grafting.

PURPOSE: Abdominal aortic aneurysm morphologic evaluation with conventional imaging techniques is inadequate when endovascular repair is being contemplated. This study has addressed the problem with magnetic resonance imaging (MRI). METHODS: Twenty patients (14 men, 6 women) with a median age of 73 years were recruited and assessed according to current endovascular graft selection criteria. Thirteen patients subsequently underwent open aneurysmorrhaphy, and the intraoperative parameters have been compared with those of duplex ultrasonography and MRI. RESULTS: No significant difference was demonstrated in the diameter of the infrarenal neck among ultrasonography, MRI, and intraoperative findings (p > 0.05, Mann Whitney U Test) and also during assessment of infrarenal neck length; however, duplex sonography accurately defined the renal ostia in only five cases. MRI visualized 38 of 40 renal arteries. Distal aortic involvement (cuff diameter and length) and the length and diameter of the common iliac arteries were accurately determined by MRI in all cases, and no significant difference was demonstrated with the intraoperative findings. Comparison of the intraoperative and MRI aneurysm lengths suggested a slight trend of overestimation by MRI resulting from angulation of the aneurysm, but this figure did not reach statistical significance. Only two patients met the current criteria for endoluminal straight grafting. CONCLUSIONS: Both MRI and duplex sonography accurately predicted aortic morphologic characteristics; however, MRI provided the most comprehensive anatomic picture for patient selection and should be considered the nonionizing imaging modality of choice when an endovascular repair is being contemplated.

Aged↗
PubMed1995

The changing workload of a surgical unit with a vascular interest.

OBJECTIVES: To examine the changing relationship between general and vascular surgical workload on a vascular "firm", over a 6-year period. DESIGN: Retrospective review. SETTING: Leicester Royal Infirmary and Professorial Surgical Unit, U.K. 1987-1992. METHOD: Analysis of audit of all surgical admissions. Relation of vascular surgery to general surgery. RESULTS: There has been a slight decrease (5%) in the number of general surgical elective admissions. Overall, the number of general surgical admissions, both elective and emergency, show a slight increase of about 3%. In contrast the number of vascular admissions increased by 42%. Of the general surgical procedures carried out 75.9% were either minor or intermediate, whereas 92.5% of vascular procedures were coded as major or higher. There has been a three times increase in the number of carotid endarterectomies, a similar increase in the number of the femorodistal bypass grafts and a halving of the number of major amputations. There has also been a five times increase in the number of angioplasties carried out. CONCLUSIONS: Our figures show the progressive, rapid increase in vascular surgical workload, compared to general surgery, and the need for the continued expansion of vascular surgery as a speciality.

Abdominal Pain↗
PubMed1995

Attachment, replication and thrombogenicity of genetically modified endothelial cells.

UNLABELLED: Endothelial cell seeding of prosthetic surfaces has been proposed as a technique to improve the patency of vascular grafts following arterial reconstruction. The introduction of specific recombinant DNA into seeded endothelial cells may enhance the anti-thrombogenic nature of the endothelial-blood interface with a consequent reduction in graft thrombosis. However, the successful use of genetically modified endothelial cells in the seeding process relies on the cells retaining normal function in terms of cellular replication, attachment and secretion of anti-thrombotic mediators. Successful genetic manipulation of human endothelial cells has been accomplished by viral and chemical methods. AIM: To study the functional characteristics of electrontransfected endothelial cells. METHODS AND RESULTS: Endothelial cells were electro-transfected with the test plasmid pTCF at a transfection efficiency of 10% utilising a single electric pulse with an electric field of 1000 volts/cm and a time constant of 12.8ms. The functional status of transfected endothelial cells was then compared with a control endothelial cell population. There were no significant differences in replication (p = 0.76), attachment (p = 0.43), basal (p = 0.89) or stimulated (p = 0.11) prostacyclin release between transfected cells as compared with control endothelial cells. CONCLUSIONS: Genetically modified cells are functionally normal, and may be used in endothelial cell seeding of prosthetic vascular surfaces.

Blood Vessel Prosthesis↗
PubMed1995

Optimisation of gene transfer into vascular endothelial cells using electroporation.

OBJECTIVES: We have examined the conditions required to obtain optimum transfection efficiencies for human umbilical vein endothelial cells by transduction with a plasmid conferring neomycin resistance. MATERIALS AND METHODS: Preliminary studies examined the effects of electric discharges using the Biorad Gene Pulser on endothelial cells. Post-electroporation, there was a significant decrease in cell survival with increasing voltages (100-400 volts; p = 0.03), capacitances [125-960 microFarads (microF); p = 0.02], number of electric pulses (1-2; p = 0.03) and decreasing cell concentrations (p = 0.01). The optimal cell concentration was 3 x 10(6) cells/ml. Transfection studies utilised the neomycin resistance expressing plasmid, pTCF; transfectants were selected with the neomycin analogue G-148. RESULTS: Electro-transfection was optimised with increasing voltages (p = 0.02) and capacitances (p = 0.01) using a single pulse. Optimal transfection was obtained using 400 volts with a capacitance of 960 microF using a single pulse; the median transfection efficiency was 10%. Transduced endothelial cells stably expressed the plasmid for 12 days and at least two cell passages. CONCLUSIONS: The results indicate that endothelial cells can be efficiently transduced by electroporation to stably express an introduced gene. This may have important implications in vascular surgery.

Cell Survival↗
PubMed1995

Do-it-yourself femoropopliteal bypass.

A 74-year-old male claudicant had undergone operative repair of his bilateral varicose veins 22 years earlier. His records confirmed that on the right side he had only had a saphenofemoral disconnection. Duplex scanning and angiography of his right leg demonstrated an occluded superficial femoral artery (SFA) and a network of channels between the proximal SFA stump and the long saphenous vein (LSV). Distal SFA reconstitution occurred through two distal arteriovenous fistulas. We believe that this is the first case of a spontaneous femorodistal bypass graft secondary to neovascularisation recorded in the literature.

Aged↗
PubMed1994

Treatment and outcome of severe lower-limb ischaemia.

The overall outcome of severe lower-limb ischaemia in terms of limb salvage and mortality is poorly documented. A consecutive series of 232 severely ischaemic legs in 209 patients was therefore studied. An aggressive policy of revascularization has been pursued; this was attempted in 89 per cent of legs, with a primary amputation rate of 8 per cent. The perioperative 30-day limb salvage rate was 79 per cent with a patient mortality rate of 20 per cent. At 12 and 24 months the limb salvage rates were 74 and 71 per cent and patient survival rates 75 and 73 per cent respectively. To identify high-risk groups the effects on limb salvage and mortality of age, sex, presentation, diabetes and ankle systolic pressure of 50 mmHg or less were studied. Using life-table analysis, none of the preoperative risk factors had an effect on limb salvage and mortality. An aggressive policy of revascularization provides excellent results in the treatment of patients with severe leg ischaemia.

Adult↗
PubMed1994

Effect of pulsatile shear stress on endothelial attachment to native vascular surfaces.

An in vitro model of vascular damage was used to investigate the ability of seeded endothelial cells to resist shear stresses generated in a perfusion circuit. At perfusion rates of 100 ml/min the maximum shear stress reached 16.5 dyn/cm2. At this level the rate of cell detachment from the damaged vascular surface was 88 per cent per h for the first 20 min of flow but gradually decreased to 5 per cent per h after 90 min. These findings suggest that endothelial cells may be retained on damaged vascular surfaces in conditions that approximate to arterial flow.

Blood Flow Velocity↗
PubMed1994

Platelet deposition after angioplasty is abolished by restoration of the endothelial cell monolayer.

PURPOSE: Percutaneous transluminal angioplasty of an atheromatous plaque causes endothelial desquamation and intimal dissection with the consequent formation of a thrombogenic flow surface. In this study we investigated the hypothesis that platelet deposition after balloon angioplasty may be decreased by rapid restoration of the endothelial cell monolayer, achieved by transluminally seeding angioplasty sites with endothelial cells. METHODS: Bilateral external iliac angioplasty was performed in eight New Zealand white rabbits. One angioplasty site was isolated from the circulation and incubated with a supraconfluent endothelial cell suspension with a double balloon catheter; the contralateral angioplasty site was sham seeded with culture medium. The deposition of autologous indium 111-labeled platelets on the angioplasty sites was quantified 30 minutes after restoration of flow and was referenced to an undamaged segment of aorta that acted as a negative control. RESULTS: Platelet deposition on the nonseeded angioplasty site (13.1 x 10(4) platelets/mm2) was significantly higher than on nondilated segments (3.4 x 10(4) platelets/mm2; p = 0.014). Restorationof endothelial cell coverage by endothelial seeding significantly reduced platelet deposition on dilated arterial segments to levels not significantly higher than in controls (3.6 x 10(4) platelets/mm2; p = 0.014). CONCLUSIONS: These results illustrate that rapid reendothelialization of angioplasty sites decreases subsequent platelet deposition and may reduce the rate of acute arterial reocclusion complicating endovascular techniques.

Angioplasty, Balloon↗
PubMed1994

The effect of transluminal endothelial seeding on myointimal hyperplasia following angioplasty.

Myointimal hyperplasia develops as a generalised response to vascular injury, and may cause stenoses in 40% of all peripheral arterial reconstructions. Disruption of the endothelial monolayer is a prerequisite for the development of intimal hyperplasia, and may be the initiating event in this process. This study examined the hypothesis that restenosis following balloon angioplasty may be reduced by rapid restoration of the endothelial monolayer, achieved by endothelial seeding. Bilateral iliac angioplasties were performed in 11 rabbits. A double balloon catheter was used to seed one angioplasty site with autogenous endothelial cells; the contralateral site was sham seeded with culture medium and acted as a control. Arterial patency rates, the degree of intimal hyperplasia (IH/IEL), and the extent of endothelialisation were quantified at 1 (n = 5) and 3 (n = 6) weeks following balloon dilatation. The results suggest that transluminal endothelial seeding may be a therapeutically applicable technique as it decreases myointimal hyperplasia, and increases patency following angioplasty. This study also illustrates the protective effect of the vascular endothelium following arterial injury, and indicates that intensive efforts should be made to preserve the endothelium during vascular reconstruction.

Angioplasty, Balloon↗
PubMed1993

Effect of seeding time and density on endothelial cell attachment to damaged vascular surfaces.

An in vitro model to facilitate the study of endothelial cell seeding of damaged vascular surfaces has been developed. This may have applications in the study of endothelial seeding of angioplasty and endarterectomy sites. Using this model, the optimum endothelial seeding time for attachment to damaged vascular surfaces should not exceed 30 min and, to achieve confluent cell attachment, a seeding density > 5 x 10(5) cells/cm2 should be used.

Angioplasty, Balloon↗