Heparin plus alteplase compared with heparin alone in patients with submassive pulmonary embolism. A prospective double-blind trial of a low molecular weight heparin once daily compared with conventional low-dose heparin three times daily to prevent pulmonary embolism and venous thrombosis in patients with hip fracture. [Prevention of deep venous thrombosis of the leg by a very low molecular weight heparin fraction (CY 222) in patients with hemiplegia following cerebral infarction: a randomized pilot study (30 patients)]. A randomised trial of subcutaneous low molecular weight heparin (CY 216) compared with intravenous unfractionated heparin in the treatment of deep vein thrombosis. A collaborative European multicentre study. A randomized trial of a single bolus dosage regimen of recombinant tissue plasminogen activator in patients with acute pulmonary embolism. Long-term treatment of deep venous thrombosis with a low molecular weight heparin (tinzaparin): a prospective randomized trial. Subcutaneous heparin treatment of deep venous thrombosis: a comparison of unfractionated and low molecular weight heparin.
The use of thrombolytic agents in the treatment of hemodynamically stable patients with acute submassive pulmonary embolism remains controversial.
                We conducted a study of patients with acute pulmonary embolism and pulmonary hypertension or right ventricular dysfunction but without arterial hypotension or shock. The patients were randomly assigned in double-blind fashion to receive heparin plus 100 mg of alteplase or heparin plus placebo over a period of two hours. The primary end point was in-hospital death or clinical deterioration requiring an escalation of treatment, which was defined as catecholamine infusion, secondary thrombolysis, endotracheal intubation, cardiopulmonary resuscitation, or emergency surgical embolectomy or thrombus fragmentation by catheter.
                Of 256 patients enrolled, 118 were randomly assigned to receive heparin plus alteplase and 138 to receive heparin plus placebo. The incidence of the primary end point was significantly higher in the heparin-plus-placebo group than in the heparin-plus-alteplase group (P=0.006), and the probability of 30-day event-free survival (according to Kaplan-Meier analysis) was higher in the heparin-plus-alteplase group (P=0.005). This difference was due to the higher incidence of treatment escalation in the heparin-plus-placebo group (24.6 percent vs. 10.2 percent, P=0.004), since mortality was low in both groups (3.4 percent in the heparin-plus-alteplase group and 2.2 percent in the heparin-plus-placebo group, P=0.71). Treatment with heparin plus placebo was associated with almost three times the risk of death or treatment escalation that was associated with heparin plus alteplase (P=0.006). No fatal bleeding or cerebral bleeding occurred in patients receiving heparin plus alteplase.
                When given in conjunction with heparin, alteplase can improve the clinical course of stable patients who have acute submassive pulmonary embolism and can prevent clinical deterioration requiring the escalation of treatment during the hospital stay.
                Copyright 2002 Massachusetts Medical Society In a randomized, prospective, double-blind trial, the effect of conventional low-dose heparin (5,000 units every 8 hours) was compared with that of a low molecular weight fragment (2165 LMWH, Kabi Vitrum AB, starting 2,500 units 2 hr before surgery, and then 5,000 units subcutaneously every morning for 9 days). A total of 90 patients admitted because of hip fracture fulfilled the inclusion criteria and were analyzed for development of pulmonary embolism and deep vein thrombosis: 46 patients were included in the low molecular weight heparin (LMWH) group, and 44 in the conventional heparin group. Two and three, respectively, died before diagnostic tests were performed. In the remaining patients a ventilation-perfusion lung scan was performed 8 days after intervention. In the first 57 patients studied a bilateral ascending venography was performed on the ninth day only if clinical symptoms suggested a deep venous thrombosis. Because of the rate of venous thrombosis detected in those patients was unexpectedly low, venography was requested in the remaining 33 patients, even if the screening tests were negative. Pulmonary embolism occurred in six patients, all in the LMWH group. Deep vein thrombosis occurred in 14 patients in the LMWH group and in six patients in the conventional heparin group. Both differences are statistically significant. Mortality did not differ between the groups, nor did haemorrhagic complications. Our findings suggest that, in patients with hip fracture, LMWH is not useful at the dosage used. The effectiveness and safety of a very low molecular weight heparin fraction were evaluated in the prevention of deep-vein thrombosis in patients confined to bed due to hemiplegia consecutive to a recent cerebral infarction. CY 222 was administered within 48 hours of the stroke by one single daily subcutaneous injection of 0.6 ml (= 15,000 U AXa IC) during 14 days. This randomized pilot study involved 30 patients. The effects of CY 222 were assessed in a group of 15 patients compared with a control group of 15 untreated patients. No deep-vein thrombosis was detected by the labelled fibrinogen test in the treated group, as against 12 patients in the control group. Six patients (3 in each group) died during the study. One case of lethal pulmonary embolism was observed and confirmed at autopsy in the control group. In the remaining 5 patients, no systematic autopsy which would have asserted the absence of pulmonary embolism or drug-induced haemorrhage was performed. Numerous standard laboratory tests confirmed that CY 222 was well tolerated. The standard treatment of deep vein thrombosis is given by continuous intravenous infusion of unfractionated heparin. This entails hospitalisation, nursing care, immobility and repeated laboratory tests (e.g. activated partial thromboplastin time [APTT], platelet count). In addition approximately 10% of patients suffer major haemorrhages. The potential advantages of a low molecular weight heparin (CY 216) given subcutaneously were explored in a randomised trial with blind quantitative evaluation of venograms. The study included 166 patients and both "therapeutic efficacy" and "intention to-treat" analyses showed that subcutaneous CY 216 in fixed doses based only on body weight was more effective on the Arnesen and Marder phlebographic scores than continuous i.v. standard heparin with daily dose adjustment according to results of coagulation tests. There was no increase in the risks of pulmonary embolism, haemorrhage or clot extension. Experiments in animals have demonstrated that recombinant tissue plasminogen activator (rt-PA) produces continuing thrombolysis after it is cleared from the circulation and that thrombolysis is both increased and accelerated, and bleeding is reduced when rt-PA is administered over a short period. In previous studies in patients with thrombotic disease, rt-PA has been shown to be an effective thrombolytic agent when administered by continuous infusion over a period between 90 minutes and 8 hours. To determine whether a short course regimen of rt-PA can achieve thrombolysis, a double-blind randomized trial has been conducted in which patients with objectively established acute symptomatic pulmonary embolism who were receiving heparin were allocated to either a 2-minute infusion of rt-PA at a dose of 0.6 mg/kg (33 patients) or saline placebo (25 patients). Perfusion lung scanning was used to assess the change in pulmonary perfusion at 24 hours and seven days post-study drug administration. Thirty-four percent of the rt-PA patients had a greater than 50 percent resolution in the perfusion defect at 24 hours compared to 12 percent of placebo patients (p = 0.026). At 24 hours, the mean relative improvement in the perfusion defect was 37.0 percent in rt-PA treated patients compared to 18.8 percent in the placebo group (p = 0.017). By day 7, no difference in lung scan resolution was detected between the groups. There were no major bleeds in either group nor were there any differences in transfusion requirements between groups. Minor bleeding occurred in 15 of the rt-PA patients mainly at angiogram-catheter insertion and venipuncture sites. These results suggest that a bolus regimen of rt-PA produces accelerated thrombolysis and provides an alternative and convenient approach to thrombolytic therapy in patients with pulmonary embolism. Evaluation of the effectiveness and safety of the low molecular weight heparin (LMWH) tinzaparin versus unfractionated heparin (UFH) followed by acenocoumarol in proximal deep venous thrombosis (DVT).
                Prospective, randomized clinical trial.
                Consecutive patients (n=108) with acute leg DVT, confirmed by duplex, were randomized to either tinzaparin alone or UFH and acenocoumarol for 6 months. Patients were evaluated ultrasonographically at entry, 1, 3, 6 and 12 months. Thrombus regression, reflux distribution and the incidence of complications were studied. A cost-analysis, comparing the two treatments, was performed.
                The overall incidence of major events (mortality, DVT recurrence, pulmonary embolism, major bleeding, heparin-induced thrombocytopenia) was significantly different (p=0.035) in favor of tinzaparin (7 versus 17 events). The ultrasonographic clot volume score (an index of recanalization) decreased significantly in both treatment groups. However, tinzaparin produced significantly more extended overall recanalization from 3 months onwards (p<0.02). Thrombus regression was equivalent or in favor of tinzaparin in the different DVT subgroups and venous segments, but the statistical significance varied. Reflux showed non-significant differences overall or in subgroups. A cost-analysis resulted in favor of LMWH.
                A fixed daily dose of tinzaparin for 6 months was at least as effective and safe as UFH and acenocoumarol. Regarding major events and recanalization, there was a significant benefit in favor of tinzaparin. Long-term DVT treatment with tinzaparin could represent an alternative to conventional treatment. In a double-blind study, patients with phlebographically proven deep venous thrombosis (DVT) were treated with subcutaneous injections twice a day of either unfractionated heparin (UH; n = 27) or low molecular weight heparin (LH; n = 29) for 7 days, and the dose was adjusted until therapeutic range was reached, according to a chromogenic substrate anti-Xa assay. Forty-eight percent of the LH group did not need dose adjustment as compared to 24% of the UH group. During the course of heparin administration, deviation from initial heparin activity was frequent in both groups, but mean activity did not indicate a cumulative effect in either group. There was 1 incidence of pulmonary embolism (LH) and only 1 minor bleeding episode (UH). Half of the patients in both groups were phlebographically improved. We conclude that subcutaneous heparin treatment with UH or LH appears safe and convenient.
Based on the limited evidence found we cannot conclude whether thrombolytic therapy is better than heparin for pulmonary embolism. More double-blind RCTs, with subgroup analysis of patients presenting with haemodynamically stable acute pulmonary embolism compared to those patients with a haemodynamic unstable condition, are required.