Biomedical subjects
Publications and source records attributed to R J Lonsdale.
We present a 55-year-old lady who swallowed a 3 cm pointed metal foreign body whilst eating a sardine salad. The foreign body migrated from the hypopharynx through the parapharyngeal space and traversed the common carotid artery over a period of 12 days. The foreign body was removed by exploration of the neck.
Heparin induced thrombocytopenia with thrombosis, or the "white clot syndrome," is a rare but recognised complication of heparin therapy. The syndrome is idiosyncratic, immune mediated, and not dose dependent and therefore is equally likely to occur with prophylactic and therapeutic heparin dosage regimens. Despite published reports on the subject we were alarmed that many surgeons who regularly use heparin to prevent or treat thrombosis were unaware that heparin can induce thrombotic complications in susceptible patients. We present three typical case histories, a brief discussion of the condition, and some guidelines on its prevention and treatment.
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)
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.
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.
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.
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.
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Arteriography does not reliably distinguish between acute and chronic arterial occlusions. Seventeen patients with acute lower limb ischaemia were investigated by arteriography and by imaging with a platelet-specific monoclonal antibody (P256 Fab'); 20 MBq 111In-labelled P256 Fab' was administered intravenously and patients were imaged at intervals of between 20 min and 24 h. Thirteen patients were subsequently treated with intra-arterial thrombolysis. In six the images showed foci of increased uptake of 111In-labelled P256 Fab' and the corresponding arterial segment was recanalized. Patency to 30 days was maintained in four cases. Seven patients had negative scans, only four of whom achieved lysis, and two of these suffered early rethrombosis. The remaining four patients were excluded from thrombolysis by the arteriographic appearances. 111In-labelled P256 Fab' imaging can identify sites of acute arterial thrombosis and may have clinical applications in the management of peripheral vascular disease. Further studies are required to test whether the technique has a role to play in patient selection for thrombolysis.
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The ideal conservative treatment for lower limb oedema would be one that provided intermittent compression whilst allowing the patient to remain mobile. In this article we describe the development of a pneumatic ambulatory compression device that utilizes the patient's weight applied, during walking, to air cells under the foot to provide compression to the ankle and calf. In volunteer studies this device typically produced a cycle of interface pressure changes from 20 to 45-50 mmHg on the lower calf and 20 to 35-40 mmHg on the upper calf.