Regarding "Transfemoral endovascular aortic graft placement".
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Biomedical subjects
Publications and source records attributed to M M Thompson.
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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.
Advances in radiological techniques have allowed successful treatment of arterial stenoses situated in the distal arterial tree. This paper describes the experience at Leicester Royal Infirmary with percutaneous transluminal angioplasty (PTA) for the treatment of occluded crural arteries. Over a 27 month period, 21 patients with 24 ischaemic limbs have undergone PTA for crural artery occlusion. PTA was attempted in a total of 29 occluded crural arteries with a median length of occlusion of 6 cm (range 1-30 cm). Intraluminal recanalisation was used for short occlusions and the subintimal technique for long occlusions. Technical success with angiographic recanalisation of the artery was achieved in 25 out of 29 crural vessels (86%). Endovascular treatment of crural artery occlusion appears to be a safe and effective treatment which avoids the need for femorodistal surgery in patients with occluded calf vessels.
Ninety-five infrainguinal polytetrafluoroethylene (PTFE) bypass grafts were performed in 90 patients. Indications for surgery were severe claudication in 23 limbs (24%) and rest pain or tissue necrosis in 72 limbs (76%). Sixty-seven grafts (71%) were to the above knee popliteal artery and 28 (29%) to the infragenicular vessels. The primary, primary assisted and secondary graft patencies at 2 years in limbs with rest pain or tissue necrosis were 37, 42 and 46% respectively with a limb salvage rate of 65%. A univariate analysis was performed to identify preoperative risk factors which affected graft patency. Smoking, an ankle systolic pressure of less than 50 mmHg, presentation with rest pain or tissue necrosis and single vessel run-off all had a significant adverse effect on graft patency. However, multivariate analysis revealed that smoking was the only significant adverse variable. These findings support the view that PTFE grafts for limb salvage are worthwhile even if the distal anastomosis is below the knee and run-off is via a single vessel provided that the patient stops smoking.
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.
The impact of interventional radiology on the cumulative patency rate of 112 consecutive infrainguinal vein grafts was reviewed. The primary, primary assisted and secondary cumulative patency rates at 42 months were 40, 65 and 69 per cent respectively. The difference between primary and primary assisted patency rates (40 versus 65 per cent, P = 0.001) resulted from the early detection and treatment of stenoses in 30 grafts by percutaneous transluminal angioplasty (PTA). Interventional radiology also improved the cumulative graft patency rate through PTA of one inflow and five outflow arteries, thrombolysis of two graft occlusions, embolization of two persistent arteriovenous fistulas and salvage of one graft on the first day after operation by percutaneous aspiration of distal graft thrombus. Interventional radiology has a crucial role to play in the maintenance of infrainguinal vein graft patency; provided that graft stenoses are detected early in their development by aggressive graft surveillance, PTA is a highly effective treatment.
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.
Over a 17-year period, 2930 vascular procedures were performed for chronic lower-limb occlusive disease. During this time, the total vascular surgical workload rose significantly as a result of an increase in the rates of arterial reconstruction and percutaneous transluminal angioplasty. Although the major lower-limb amputation rate did not change significantly, there was a decrease in the above- to below-knee ratio. In addition, there were significant increases in the percentage of patients treated over the age of 75 years and the proportion of attempted revascularizations before amputation. The mortality rates for arterial reconstruction, percutaneous transluminal angioplasty and amputation did not change significantly during the study period. The duration of hospital stay increased significantly for patients undergoing amputation and decreased significantly for those receiving arterial reconstruction.
We have reviewed 3036 consecutive patients who underwent arterial reconstruction, percutaneous transluminal angioplasty, or a major amputation for lower limb peripheral vascular disease in Leicester between 1974 and 1990. Patient data were obtained from the Hospitals Activity Analysis database, which codes all patient discharges according to diagnosis and treatment. During this 17-year study period, 1132 patients have undergone arterial reconstruction, 706 patients have undergone percutaneous transluminal angioplasty, and 1198 patients have undergone major amputation. The results show that the number of arterial reconstructions and angioplasties for lower limb arterial occlusive disease has increased over the last 17 years. The total amputation rate has decreased slightly during the period studied, but overall the decrease has not been significant.
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The merits of an aggressive policy of distal reconstruction have been questioned by some observers. To determine the factors affecting graft patency and mortality, we analysed 78 consecutive infragenicular femorodistal vein grafts performed in 72 patients with critical limb ischaemia. The primary, primary assisted and secondary graft patency rates at 36 months were 29, 57 and 64%, respectively. The limb salvage and patient survival rates at 36 months were 67 and 74%, respectively. Univariate analysis (log-rank test) was performed to identify factors affecting graft patency, limb salvage and mortality at 1 month (perioperative) and 1 year. Independent variables of age, sex, diabetes, presentation, level of anastomosis and vein technique (reversed or in situ) did not affect graft patency. The ankle systolic pressure did not predict graft patency but was an independent variable affecting mortality (p = 0.047), as did diabetes (p = 0.019). These results show that excellent limb salvage can be successfully achieved in severely ischaemic patients by adopting an aggressive approach to femorodistal bypass, and that age, gender and poor medical condition are not contraindications to femorodistal bypass. The difference between the primary and primary assisted patency rates in this series is dramatic and reflects the impact of a vein graft surveillance programme in preventing graft occlusion.
The Second European Consensus Document on Chronic Critical Leg Ischaemia defines critical limb ischaemia in non-diabetic patients as rest pain or tissue necrosis (ulceration or gangrene) with an ankle systolic pressure (ASP) of less than or equal to 50 mmHg, or a toe pressure of less than or equal to 30 mmHg. The aim of this study was to investigate whether this definition is able to predict the outcome of patients with severe lower limb ischaemia and thus to determine the relevance of the definition in clinical practice. We have analysed 148 severely ischaemic limbs in 133 non-diabetic patients who presented with rest pain, tissue necrosis or a combination of these symptoms. Fifty-one percent of these limbs fulfilled the current definition with an ASP < or = 50 mmHg; 49% had an ASP > 50 mmHg and were thus not defined as critically ischaemic according to the current definition. We have compared actuarial limb salvage and mortality rates in patients with an ASP < or = 50 mmHg to those patients with an ASP > 50 mmHg. The 1 year limb salvage and mortality rates for ischaemic limbs fulfilling the European Consensus Document criteria were 78.7 and 36.7% respectively, compared to rates of 73.9 and 17.3% in patients who were not defined as critically ischaemic under the current definition. There were no significant differences between 1 year limb salvage or mortality rates between the two patients groups (p = 0.843, 0.078, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)
One of the most important prerequisites prior to femorocrural bypass is the identification of a patent calf vessel. To determine the ability of three preoperative investigations to demonstrate patent distal vessels we compared preoperative conventional arteriography, Doppler ultrasound measurement of ankle systolic pressure (ASP) and pulse generated run-off (PGR). PGR and ASP both identified significantly more calf vessels than did preoperative conventional arteriography. However, only PGR had the ability to distinguish those vessels suitable for bypass grafting from those unsuitable for grafting. These results demonstrate that PGR is the investigation of choice prior to femorocrural bypass.
Acute arterial reocclusion and late restenosis following angioplasty may be partially caused by loss of the endothelial cell monolayer during balloon dilatation. Rapid restoration of the endothelial cell monolayer by endothelial cell transplantation has the potential to increase the antithrombotic nature of the angioplasty site and also to prevent myointimal hyperplasia which is the cause of late restenosis. We have investigated a method to transluminally deliver endothelial cells to angioplasty sites using a double balloon catheter with a central instillation port. Inflation of the balloons allows a segment of artery to be isolated from the circulation which may then be incubated with infused endothelial cells. The external iliac arteries of New Zealand white rabbits were dilated for 30 s at 8 atm pressure using a 3 mm balloon angioplasty catheter. Indium-111 labelled allogeneic rabbit endothelial cells were seeded onto the angioplasty site and retained in contact with the vascular surface for 30 min by continued inflation of the isolation balloons. After 30 min, the balloons were deflated and flow restored. Percentage cell retention was calculated by determining the gamma activity of the seeded angioplasty site, and referencing this to the contralateral sham seeded site. Results are expressed as a median with 95% confidence intervals and suggest that endothelial cells may be successfully delivered and retained on damaged vascular surfaces [table: see text].
We present a case of leiomyosarcoma of the intrahepatic inferior vena cava extending into the right atrium, that has been successfully palliated by removal of the obstructing tumour under conditions of full cardiopulmonary bypass and circulatory arrest. Lesions of this kind have previously thought not to be amenable to surgery. Although resection was incomplete, successful palliation may be achieved facilitating this technique.
The management of patients with carotid artery disease who require coronary artery bypass grafting (CABG) remains controversial. Several published series from the USA (including one with prospective randomization) advocate a combined approach of carotid endarterectomy (CEA) followed immediately by coronary artery bypass surgery. However, experience of combined carotid endarterectomy and coronary bypass grafting has not been previously reported by a centre from the United Kingdom. Between 1986 and 1991 we performed this combined procedure on 18 patients who required myocardial revascularization and had co-existing severe (> 70%) carotid stenosis. Sixteen patients (89%) had angina and 11 patients (61%) had symptomatic carotid artery disease. The perioperative mortality was 5.5% and the ipsilateral perioperative stroke rate was 5.5%. These early results are encouraging and suggest that further evaluation of combined carotid endarterectomy and coronary artery bypass surgery is warranted.