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Biomedical subjects

B R Hopkinson

Publications and source records attributed to B R Hopkinson.

At least 73 records · Page 4Linked to original sources
PubMed1995

Transfemoral insertion of a bifurcated endovascular graft for aortic aneurysm repair: the first 22 patients.

The purpose of this study was to evaluate and optimize a system of transfemoral bifurcated graft insertion for endovascular repair of infrarenal aortic aneurysm. Grafts were inserted through bilateral femoral arteriotomies in 22 patients. Placement was guided by fluoroscopy. Results were assessed by completion angiography, with computed tomography scanning or duplex ultrasonography at 1, 3 and 6 months. The first 11 insertions were complicated by failed insertion in two cases, proximal leakage in one, graft limb thrombosis in five and wound infection in one. The second 11 insertions were complicated by retrograde leakage around the distal graft orifice in two patients. One of these was associated with aneurysm rupture, leading to the sole mortality of the series. There were no instances of graft migration or embolism. In conclusion, the lessons learned during the first 11 insertions were responsible for the improved results apparent in the second 11 insertions. When applied in properly selected patients, transfemoral insertion of a bifurcated graft is a reliable method of isolating an aortic aneurysm from the circulation.

Aortic Aneurysm, Abdominal↗
PubMed1995

Prospective randomised comparative study of pulse spray and conventional local thrombolysis.

OBJECTIVES: To compare the time required to achieve lysis with the pulse spray technique and the conventional slow continuous infusion technique. DESIGN: Prospective randomised open Study. METHODS: Eighteen patients suitable for intra-arterial thrombolytic therapy with conventional and pulse spray technique were randomised 1:1 to receive either pulse spray thrombolysis with 0.33 mg/ml rt-PA injected as a bolus of 0.2 ml or conventional thrombolysis with 0.05 mg/ml rt-PA infused at a rate of 10 ml/h. RESULTS: The age, duration of symptoms, length of occlusion and prethrombolysis ankle brachial pressure index were comparable in the two groups. The median duration of thrombolytic therapy in the pulse spray group was 195 min (range 90-1260) compared to 1390 min (range 300-2400) in the Conventional group. The difference between the two groups was significant, p < 0.002 (Mann-Whitney test). CONCLUSIONS: Significantly shorter time is required to achieve local thrombolysis with pulse spray compared to the conventional infusion method.

Aged↗
PubMed1995

Carbon dioxide: an alternative to iodinated contrast media.

OBJECTIVES: To study the use of carbon dioxide as a contrast medium for arteriography. METHODS: Carbon dioxide was used as a contrast medium for intra-arterial digital subtraction lower limb angiography in 12 examinations on 11 patients. RESULTS: No complication was encountered and no significant changes occurred in the arterial pH, PaCO2 and PaO2. The quality of images as assessed by an independent observer was adequate for the majority of the vessels (77%). CONCLUSIONS: Carbon dioxide is a safe alternative in patients at an increased risk of adverse reaction to iodinated ionic or non-ionic contrast medium and is very cheap.

Aged↗
PubMed1994

Transfemoral endoluminal repair of abdominal aortic aneurysm with bifurcated graft.

Traditional open repair of abdominal aortic aneurysm has disadvantages. We present our experience of transfemoral endoluminal repair with a bifurcated graft system. 29 patients with aortic aneurysm over 5.5 cm in diameter and 1 with a 3.2 cm aneurysm and bilateral iliac stenosis were assessed; 5 were suitable for the procedure. The operation was successful in all the patients, without haemodynamic compromise or major complications. This technique has the potential to reduce morbidity and mortality from abdominal aortic aneurysm. Further modifications are required to make it applicable to most aneurysms.

Aged↗
PubMed1994

Experience with pulse-spray technique in peripheral thrombolysis.

Pulse-spray thrombolysis (PST) is a new technique of accelerated peripheral arterial thrombolysis. This technique has been evaluated on 24 patients with limb ischaemia. Severe acute limb-threatening ischaemia with sensory and motor deficit was present in 11/24 (45.8%) patients. The median dose of recombinant tissue plasminogen activator (rt-PA) used was 18 mg (10-35 mg) injected in a concentration of 0.33 mg/ml and bolus size of 0.2 ml. The median length of occlusions treated was 23 cm (range 4-55 cm). Complete initial lysis was achieved in 23/24 (95.8%) and limb salvage at 30 days was achieved in 18/24 (75%) of the cases. The overall 30-days mortality was 4/24 (16.6%) and 2/4 (50%) in those who required surgical intervention. The median duration of thrombolytic treatment was 137.5 minutes (range 35-1125 minutes) which is an 11-fold and significant reduction (p < 0.001, Mann-Whitney) in lysis time compared with the results of conventional low dose infusion of rt-PA at a rate of 0.5 mg/h in 120 consecutive patients in our unit. PST rapidly restores vascular patency and may become the treatment of choice for acute limb ischaemia including those at immediate risk of irreversible ischaemic injury which would not be considered suitable for conventional thrombolysis.

Adult↗
PubMed1994

Obesity as a risk factor in major reconstructive vascular surgery.

In a prospective analysis of 150 consecutive major vascular reconstructions, 104 patients were of normal weight (NW), 33 were overweight (OW) and 13 were obese (OB), as defined by body mass index calculations (BMI = kg/m2). Wound infections were more common in OW than NW patients (10/33 versus 10/104, p < 0.01) and in the OB compared to the NW group (4/13 versus 10/104, p < 0.05). Wound dehiscence was more common in the combined OW and OB groups than the NW patients (3/46 versus 0/104, p < 0.01). Chest infections were more common in OB (4/13) than NW (9/104) patients (p < 0.02). Median (interquartile range) in-patient stay was longer in OB patients [34 (15-41) days] compared to OW [14 (10-19) days, p < 0.001] and NW [11 (8-15) days; p < 0.001] patients. Nonetheless, there were no significant differences in the rates of more major complications or operative mortality between the three groups and early infrainguinal graft patency and limb salvage rates were not different. Only one prosthetic graft infection occurred in this series. In conclusion, despite the higher risk of infective complications, major vascular reconstruction can be performed safely in overweight and obese patients.

Aged↗
PubMed1994

Endoscopic transthoracic sympathectomy: successful in hyperhidrosis but can the indications be extended?

Endoscopic transthoracic sympathectomy (ETS) has recently become established as a successful treatment for severe palmar and axillary hyperhidrosis. In this unit the indications for ETS have been broadened to include patients with Raynaud's syndrome and critical upper limb ischaemia and this paper is primarily concerned with analysing outcome in relation to the indication for operation. In all, 68 operations have been attempted in 40 patients and complete follow-up details are available on 62 treated limbs. One operation was a technical failure because of an obliterated pleural cavity. In the hyperhidrosis group (n = 28), all the affected areas showed symptomatic improvement at a median follow-up of 17 months. In the Raynaud's group (n = 30), 28 limbs (93%) were improved to some degree at the time of discharge, but at a median follow-up of 18 months only 15 limbs (50%) remained symtomatically improved to some degree. The four upper limbs treated for critical ischaemia were improved by ETS and no amputations were necessary. Significant postoperative chest pain was noted by nine patients (23%). There were three postoperative pneumothoraces, two intercostobrachial neuralgias and one transient Horner's syndrome. The cosmetic result was reported as excellent or good by 97% of patients. As with other forms of surgical thoracic sympathectomy, excellent early results are not maintained in the longer term when ETS is used to treat Raynaud's syndrome. Nevertheless, the greater simplicity and lower morbidity of the endoscopic method suggest that it can be offered to Raynaud's sufferers with greater impunity than open sympathectomies.

Adolescent↗
PubMed1993

A study of the use of the thromboxane A2 antagonist, sulotroban, in combination with streptokinase for local thrombolysis in patients with recent peripheral arterial occlusions: clinical effects, platelet function and fibrinolytic parameters.

In peripheral thrombolysis adjuvant anti-platelet therapy may help to lyse otherwise resistant thrombus, thereby increasing the number of patients successfully treated and reducing the "time to lysis". If continued after lysis it may help to prevent early rethrombosis. In this pilot study 21 patients undergoing peripheral thrombolysis with streptokinase were randomised to receive the thromboxane receptor antagonist sulotroban or placebo. The dose of sulotroban given was 2 mg/min (four patients), 4 mg/min (five patients) or 8 mg/min (four patients), eight patients received placebo. The clinical and laboratory effects of the treatment were monitored. Thrombolysis was achieved more quickly in patients receiving sulotroban, however, there was no difference between groups in the number of patients in whom recanalisation was achieved (six of eight receiving placebo and eight of 13 receiving sulotroban) or in the number of cases of early rethrombosis. During lysis there was an increase in plasma beta-thromboglobulin with similar levels being found in patients receiving sulotroban and streptokinase and those receiving streptokinase alone. No other major changes in platelet function during lysis were seen in patients receiving streptokinase alone. Sulotroban significantly reduced platelet aggregation and 14C-5HT release in response to several platelet agonists. With the thromboxane mimetic U46619 the degree of inhibition of aggregation and 14C-5HT release depended on the dose of sulotroban used. High levels of inhibition were associated with an excess of haemorrhagic complications especially in combination with a low plasma fibrinogen level. We conclude that the use of low dose sulotroban in combination with streptokinase merits further study and may hve a role in accelerating lysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

Peripheral arterial thrombolysis: intermediate-term results.

To determine the intermediate-term results of intra-arterial thrombolysis, 127 consecutive patients receiving 129 courses of treatment were reviewed at a median follow-up of 3 years. At initial review, 30 days after treatment, thrombolysis was successful in 63 cases (49 per cent). Of these patients, 16 were lost to follow-up: 15 died without further vascular symptoms and one moved from the area. Some 35 patients were alive and asymptomatic, of whom 33 had either angiographic or clinical evidence of continued arterial patency. Symptomatic reocclusion occurred in 12 cases; a further two patients remained asymptomatic and reocclusion was detected at follow-up. Two of the 12 symptomatic patients required amputation. Estimated patency rates were 80 per cent at 1 year, 72 per cent at 2 years and 70 per cent at 3 years. The intermediate-term results in the 66 cases in which lysis was unsuccessful were worse, only 16 patients (24 per cent) surviving to follow-up with the treated limb intact. It is concluded that, if thrombolysis is successful at 30 days, the intermediate-term results are good.

Adult↗
PubMed1993

Acute limb deterioration during intra-arterial thrombolysis.

Approximately 12 per cent of limbs undergoing intra-arterial thrombolysis (IAT) develop distal embolism or extension of thrombus during the procedure. These are usually of little clinical consequence and can be treated by increasing the rate of administration of the lytic agent. However, in some patients the clinical condition of the limb deteriorates rapidly. In an attempt to define the incidence of acute limb deterioration during IAT, information was collected from five centres in the UK with experience of the technique. A total of 866 treatments were recorded, with 20 limbs (2.3 per cent) undergoing acute deterioration. This complication was more common during the treatment of thrombosed popliteal aneurysm than during that of emboli or thrombosed atheromatous arteries or grafts (P < 0.001). The amputation rate associated with the complication was high, and operative intervention provided better results than continuation of lysis.

Aneurysm↗
PubMed1992

Recombinant tissue-type plasminogen activator is superior to streptokinase for local intra-arterial thrombolysis.

The results of local intra-arterial thrombolysis in 98 patients treated with streptokinase and 69 patients treated with recombinant tissue plasminogen activator (rtPA) have been compared. The two groups of patients were well matched and their treatment protocols were identical except with regard to the thrombolytic agent used. Strict criteria for defining successful thrombolysis were used. Successful lysis was achieved in 40 of 98 patients (41 per cent) receiving streptokinase and 40 of 69 patients (58 per cent) receiving rtPA (P less than 0.05). The time to lysis was significantly shorter with rtPA, median time 22 h, than with streptokinase, median time 40 h (P less than 0.002). There was no difference in the incidence of haemorrhagic complications. These results suggest that rtPA is superior to streptokinase for local intra-arterial thrombolysis.

Adult↗
PubMed1992

Fibrinolytic enhancement with a prostaglandin analogue iloprost.

Earlier workers have suggested a possible fibrinolytic effect using prostaglandin or prostaglandin analogues. Despite using maximum tolerated doses of the prostaglandin analogue Iloprost, we have been unable to demonstrate any significant effect on fibrinolysis in patients with stage IV peripheral vascular disease (Fontaine classification).

Fibrinolysis↗
PubMed1992

Detection of left heart thrombus by echocardiography is not essential before peripheral arterial thrombolysis.

Left heart thrombus has been regarded as a contraindication to thrombolysis. In this prospective study the role of echocardiography before thrombolysis in the cardiac assessment of 51 patients undergoing thrombolysis for a peripheral arterial occlusion was evaluated. Ten patients with positive echocardiograms were identified. Echocardiography contributed to the diagnosis of embolus in one patient. All eight patients with embolic arterial occlusions were successfully recanalized, comparing favourably with a success rate of 58% in patients with thrombotic occlusions. There were no embolic complications during thrombolytic treatment or in the subsequent 30 days. We conclude that thrombolysis can be performed safely despite the presence of left heart thrombus.

Adult↗
PubMed1991

Double-blind randomized trial of perioperative fibrinolytic enhancement for femoropopliteal bypass.

Patients with rest pain or acute peripheral arterial thrombosis are known to have impaired endogenous fibrinolysis, which is associated with an increased risk of early vascular graft thrombosis. This risk is exacerbated by the fibrinolytic shutdown which is known to occur after major surgery. Stanozolol, which has been demonstrated to enhance endogenous fibrinolysis, was therefore used in an attempt to prevent this perioperative fibrinolytic shutdown and so enhance graft patency. Twenty-seven patients were randomized to receive either 50 mg stanozolol or placebo intramuscularly 24 h before operation, followed by a 6 week course of either 5 mg stanozolol or placebo orally, twice daily. On the second day after operation, 10-11 MBq of autologous 111indium-labelled platelets were injected, with scanning over the graft on the 3 following days. Despite using a large depot of stanozolol, significant effects, such as raised plasminogen (P less than 0.001), reduced fibrinogen (P less than 0.001) and reduced euglobulin lysis time (P less than 0.001), were not seen until the seventh day after operation, with maximum benefit at 6 weeks. This was reflected in the 111indium-labelled platelet deposition studies. The placebo group had a progressive increase in platelet deposition on all 3 days. In contrast, those receiving stanozolol showed a lower, static picture of deposition. However, these changes did not attain statistical significance. Three patients experienced early graft thrombosis, two in the placebo group and one in the stanozolol group. Only an incomplete inhibition of the perioperative fibrinolytic shutdown was achieved. Much longer preoperative courses are thus required to allow the maximum effect to be present at the most crucial time. At present, perioperative fibrinolytic enhancement does not appear to be a practical proposition, and we must await the development of new safer and more potent agents.

Aged↗
PubMed1991

Randomized trial of intra-arterial recombinant tissue plasminogen activator, intravenous recombinant tissue plasminogen activator and intra-arterial streptokinase in peripheral arterial thrombolysis.

Sixty patients were recruited into a randomized parallel group comparison of three thrombolytic regimens for acute or subacute peripheral arterial thrombosis. There were no significant differences in age, duration of history, length of occlusion or presence of neurosensory deficit between the groups. Initially successful lysis was significantly greater with intra-arterial (IA) recombinant tissue plasminogen activator (rt-PA) than with either streptokinase (Sk) (P less than 0.04) or intravenous (IV) rt-PA (P less than 0.01). The duration of therapy varied from a median of 35 h with IA rt-PA to 40 h with Sk (P greater than 0.5). The median (confidence interval) increase in ankle:brachial pressure index following IA rt-PA of 0.57 (0.33-0.82) was significantly higher than for either Sk of 0.24 (0-0.57) or for IV rt-PA of 0.18 (0-0.41). Limb salvage at 30 days was achieved in 80, 60 and 45 per cent respectively for IA rt-PA, Sk and IV rt-PA. Haemorrhagic complications occurred in six patients following Sk and in 13 following IV rt-PA; only one minor haemorrhage occurred following a catheter perforation in a patient who received IA rt-PA (P less than 0.05). IA rt-PA provides a more effective, safer fibrinolytic regimen than conventional therapy with Sk. IV rt-PA has not been as successful and carries a significantly higher risk of haemorrhagic complications.

Aged↗