Dose escalation of low molecular weight heparin in patients with recurrent cancer-associated thrombosis

Introduction

Patients with cancer-associated thrombosis are at a high risk of developing recurrent events despite anticoagulant therapy. Escalation of the dose of low molecular weight heparin (LMWH) has been suggested as a potential treatment option to manage these patients. We sought to confirm the benefit and risk of this management strategy in patients with recurrent cancer-associated thrombosis.

Material and Methods

A retrospective cohort study of consecutive cancer outpatients seen for management of a symptomatic recurrent cancer-associated thrombosis while on anticoagulation was undertaken. Objectively confirmed episodes of recurrent thrombosis were treated with either dose escalation of LMWH or initiation of therapeutic dose of LMWH in patients already anticoagulated with LMWH or vitamin K antagonist (VKA) respectively. Included patients were followed for a minimum of 3 months after the index recurrent event.

Results

Fifty-five cancer patients with a recurrent venous thromboembolism (VTE) despite anticoagulation were included. At the time of the recurrence, 89% of patients were on LMWH. The median time between the initial cancer-associated thrombosis to the index recurrent event was 2.3 months (range 0.1 to 30.4 months). Four patients (7.3%; 95% CI: 2.0 to 17.6%) had a second recurrent VTE during the 3-month follow-up period. Three patients (5.5%; 95% CI 1.1 to 15.1%) had major bleeding complications after dose escalation of LMWH. There were no recurrent fatal VTE or major bleeding episodes.

Conclusion

Escalating the dose of LMWH seems effective and safe for managing patients with recurrent cancer-associated thrombosis despite anticoagulant therapy.     

Low molecular weight heparin for deep vein thrombosis in glioma patients

The treatment and secondary prophylaxis of deep vein thrombosis (DVT) and pulmonary embolism, a common complication in patients with malignant glioma, has remained controversial. We treated 11 patients with malignant glioma and DVT prospectively with low molecular weight heparin (LMWH) at 175 IU/kg for 10 days and then for 3 months at 100 IU/kg. No patient developed bleeding complications or any other severe side effects of LMWH treatment. Two patients had a dose reduction of LMWH to 75 IU/kg because of chemotherapy-induced thrombocytopenia. One patient developed progressive DVT and nonlethal pulmonary embolism on day 14 of LMWH 100 IU/kg. After increasing the dose to 175 IU/kg he had no further recurrence. One patient had recurrence of DVT after a fracture of the leg affected by DVT at 8 months after the diagnosis of DVT and 5 months after the end of LMWH therapy. LMWH therapy may be safe and effective in the treatment and secondary prophylaxis of DVT in patients with malignant glioma. Received: 4 January 2002, Received in revised form: 18 April 2002, Accepted: 23 April 2002 Correspondence to Dr. F. Schmidt     

Low molecular weight heparin and prevention of postoperative thrombosis in abdominal surgery.

In a prospective, double-blind, randomized multicenter trial the efficacy and safety of low molecular weight heparin and unfractionated heparin were compared for the prevention of postoperative deep vein thrombosis in patients undergoing abdominal surgery. Six hundred and seventy-three patients were randomly allocated to the two prophylaxis groups; 20 of these, however, did not undergo surgery and did not receive any prophylaxis. Of the remaining 653 patients 323 received one subcutaneous injection of 3,000 anti-Xa units of low molecular weight heparin and 330 received subcutaneously 5,000 U heparin three times a day. Treatment was initiated 2 h preoperatively and continued for 7 to 10 days. The occurrence of DVT was determined by the 125I-labelled fibrinogen uptake test and phlebography. Venous thrombosis was diagnosed in 24 of 323 patients (7.4%) treated with low molecular weight heparin and in 26 of 330 patients (7.9%) treated with low-dose heparin. DVT of proximal veins was detected in four patients of the low molecular weight heparin group and in three patients of the low-dose heparin group. During the observation period three pulmonary emboli - one fatal and two non-fatal - occurred in patients receiving prophylaxis with low-dose heparin. No pulmonary embolism was found in patients treated with low molecular weight heparin. Both prophylactic schemes were well tolerated. Intra- and postoperative blood loss, incidence of wound hematoma, frequency and volume of intra- and postoperative blood transfusion were similar in both groups with a slight advantage for the low molecular weight heparin group.(ABSTRACT TRUNCATED AT 250 WORDS)     

低剂量低分子肝素钠预防脑出血患者下肢深静脉血栓形成临床体会

目的探讨脑出血患者应用低分子肝素钠预防下肢深静脉血栓形成的安全性及有效性。方法将2011年1月至2013年3月期间收治的103例脑出血患者随机分为治疗组及对照组。对照组42例,给予常规治疗;治疗组61例,常规治疗基础上入院后第1~14天皮下连续注射低分子肝素钠4000IU·d-1。收集两组患者的临床资料进行统计学分析。结果治疗组发生1例深静脉血栓形成和1例颅内再出血,无肺栓塞发生;对照组8例发生深静脉血栓形成和3例肺栓塞,无颅内再出血发生。两组下肢深静脉血栓形成及肺栓塞发生率差异有统计学意义(P<0.05),颅内再出血差异无统计学意义(P>0.05)。结论皮下注射低剂量低分子肝素钠是预防脑出血患者下肢深静脉血栓形成的有效措施。     

Enoxaparin vs heparin for prevention of deep-vein thrombosis in acute ischaemic stroke: a randomized,double-blind study

OBJECTIVES: To compare the efficacy, safety, and overall risk-benefit profile of enoxaparin and unfractionated heparin (UFH) prophylaxis of venous thromboembolic complications in patients with acute ischaemic stroke. METHODS: Patients with ischaemic stroke resulting in lower-limb paralysis lasting for at least 24 h and necessitating bedrest, were randomized within 48 h of the onset of stroke, and treated with enoxaparin (40 mg subcutaneously once daily) or UFH (5000 IU subcutaneously thrice daily) for 10 +/- 2 days. Main outcome measures were deep-vein thrombosis, pulmonary embolism (PE), death from any cause, intracranial haemorrhage including haemorrhagic infarction, or any other major bleeding. RESULTS: Outcome events occurred within 3 months of stroke in 40/106 patients treated with enoxaparin (37.7%) and 52/106 patients treated with UFH (49.1%, P=0.127). Fewer patients treated with enoxaparin (14, 13.2%) than with UFH (20, 18.9%) had evidence of haemorrhagic transformation of ischaemic stroke. CONCLUSIONS: Enoxaparin administered subcutaneously once daily was as safe and effective as subcutaneous UFH given thrice daily in the prevention of thromboembolic events in patients with lower limb paralysis caused by acute ischaemic stroke.     

An international standard for low molecular weight heparin

An international collaborative study has been carried out with the aim of establishing an international standard for low molecular weight (LMW) heparin. Three preparations of LMW heparin were assayed against the International Standard for unfractionated heparin (UFH) by 25 laboratories in 13 countries, using nine different assay methods. The results confirmed previous findings of non-parallel assays, wide interlaboratory variability and differences between methods when LMW heparins are assayed against a UFH standard. Use of one of the LMW heparins as a standard for the other two gave parallel assays and much closer agreement between laboratories. The preparation in ampoules coded 85/600 was selected as likely to give the best agreement with the largest number of LMW heparins; potencies were assigned by taking the mean of all the anti-Xa assays, and the mean of the thrombin and APTT assays, to represent the two major groups of activities. Preparation 85/600 has been established by WHO as the 1st International Standard for LMW heparin, with potencies of 1,680 iu/ampoule by anti-Xa assays and 665 iu/ampoule by thrombin inhibition and APTT assays.     

A human pharmacological study comparing conventional heparin and a low molecular weight heparin fragment

The pharmacokinetics of a heparin fragment of low molecular weight (LMWH) of 4000-5000 D and unfractioned standard heparin (UFH) have been studied after i.v. injections of different doses and infusions in 8 humans. The heparin activity was significantly higher and the effect on APTT lower after LMWH fragment as compared to UFH in the same doses. The half-life of heparin activity was about 1 hr for UFH and about 2 hr for LMWH. LMWH was found to be eliminated according to first order kinetics and there were no signs of dose dependency.     

A low molecular weight heparin compared with unfractionated heparin

A 6000 daltons low molecular weight heparin (LMWH) was compared with unfractionated mucosal heparin in vitro and in vivo. Despite unimpressive specifications by clotting assays in vitro, the LMWH gave high and sustained activity in vivo by anti-Factor Xa assays, following subcutaneous injection. However, activity measured by APTT and calcium thrombin time assays was at least as high as occurred following unfractionated heparin. On the basis of clotting assays, there seems no reason to expect a lower incidence of haemorrhagic side-effects following the clinical use of this LMWH. The study also strikingly demonstrates the inadequacy of in vitro clotting assays for assessing the in vivo behaviour of LMWH.     

A randomized double-blind study between a low molecular weight heparin Kabi 2165 and standard heparin in the prevention of deep vein thrombosis in general surgery. A French multicenter trial

The safety and efficacy of a low molecular weight heparin fragment Kabi 2165, given in the dose 2,500 anti-Xa units once daily, in preventing postoperative venous thromboembolism, was assessed against calcium heparin in the dose 5,000 IU twice daily, in a multicenter double blind randomized study. On an intention to treat basis 385 patients scheduled for major surgery were included in this study. Six patients (3.1%) out of 195 developed isotopic DVT in the Kabi 2165 group. Corresponding figures for calcium heparin was 7 patients (3.7%). There was no statistically significant difference between the two groups with respect to the bleeding variables; blood loss during operation, postoperative drainage, blood transfusion, haemoglobin and haematocrit levels; wound haematoma and haematoma at the injection sites. No patient had to undergo evacuation of wound haematoma or reoperation due to bleeding. It is concluded that one single daily injection of Kabi 2165 provides a convenient safe and effective prophylaxis against thromboembolism in general surgery.     

The influence of low molecular weight heparin in combination with dihydroergotamine on experimental thrombosis and haemostasis

The influence of low molecular weight heparin in combination with dihydroergotamine (DHE) on thrombus formation and primary haemostasis was investigated in rabbit models. Conventional heparin in the dose of 60 units anti Xa activity/kg b. w. effectively prevented thrombus formation but the same dose of a low molecular weight fragment only gave a marginal decrease of the frequency of thrombosis. The thrombus weight was, however, significantly reduced. Doubling the dose of the heparin fragment totally abolished thrombus formation as did the combination of 60 units with DHE. With DHE it was also possible to diminish the low molecular weight heparin dose to 30 units with a good prophylactic effect. There was a small but significant increase of haemostatic plug formation time in all treatment groups except the one with low molecular weight heparin fragment 30 units anti Xa activity combined with DHE. Thus, by combining low molecular weight heparin in a low dose with DHE it is possible to prevent thrombus formation without influencing primary haemostasis in rabbits.     

Randomized double-blind, placebo controlled safety study of a low molecular weight heparinoid in patients undergoing transurethral resection of the prostate

In preparation for an efficacy study, the effect of the low molecular weight heparinoid Org 10172 on postoperative blood loss was assessed in a randomized double-blind, placebo controlled study in patients undergoing transurethral resection of the prostate (TURP). Org 10172 and placebo were given twice daily as i.v. injection for three postoperative days starting one hour preoperatively. Three doses of Org 10172 (800, 1600, and 2400 anti-Xa units b.d.) were evaluated against placebo in three consecutive patient blocks respectively. Each block consisted of 20 patients, 15 receiving Org 10172 and 5 patients placebo. The study was discontinued after 9 patients of the third block had completed the protocol because of excessive urinary blood loss. Data analysis showed a dose-dependent increase in postoperative haemoglobin loss, this was not significant for the 800 anti-Xa units b.d. dosage but was significant in those patients treated with 1600 (p less than 0.05) and 2400 anti-Xa units b.d. (p less than 0.01). It was concluded that the heparinoid Org 10172 caused a dose dependent increase in urinary blood loss following TURP.     

Subcutaneous treatment of deep venous thrombosis with low molecular weight heparin. A dose finding study with LMWH-Novo

Treatment of deep venous thrombosis with low molecular weight heparin (LMWH-Novo, Logiparin) was carried out with two different doses of Logiparin, 75 XaI U/kg b.w. twice daily and 150 XaI U/kg b.w. once daily subcutaneously for 5 days. Simultaneously warfarin was given from the first day of heparin treatment. Mean age of the twenty patients was 65 years and one third was females. No serious side effects, hematomas, pulmonary emboli or signs of recurrent thrombosis occurred during treatment with either dose regime. Venografic assessment with Marder scoring one week after initiation of Logiparin treatment showed a slight not significant improvement apparent in 40 % of the patients. The activities of F-IIaI and F-XaI in the blood plasma were found to increase after injection of Logiparin. These two parameters seem to be the most suitable for monitoring the effect during treatment. For future studies on the therapeutic effect of Logiparin in deep venous thrombosis a single dose of 150 to 200 F-XaI activity per 24 hours seems to be most suitable.     

Prevention of postoperative venous thrombosis: a randomized trial comparing unfractionated heparin with low molecular weight heparin in patients undergoing total hip replacement

A double blind randomized trial comparing subcutaneous enoxaparin (40 mg once daily) with standard unfractionated calcium heparin administered at a dose of 5,000 units every 8 hours in patients undergoing elective hip replacement has been performed. Treatment regimens began 12 hours preoperatively with enoxaparin, 2 hours preoperatively with standard unfractionated calcium heparin, and were continued for 15 days or until discharge. Venography was performed in all patients. Two hundred thirty-seven patients were included in the study: 113 received unfractionated heparin and 124 received enoxaparin. The incidence of proximal deep vein thrombosis was reduced from 18.5% in the unfractionated heparin group to 7.5% in the enoxaparin group (p = 0.014), and the incidence of total deep vein thrombosis was similarly reduced from 25% to 12.5% (p = 0.03). There were two major bleeding episodes and one minor bleed in the enoxaparin group compared to two minor bleeds in the unfractionated heparin group. Patients who received enoxaparin required fewer red blood cell transfusions and had a significantly higher hemoglobin on postoperative days 3 and 4. Thus prophylaxis with enoxaparin, 40 mg once daily, is simple, safe and more effective than standard low dose unfractionated heparin in preventing deep vein thrombosis in patients undergoing elective hip replacement.     

Fixed-dose,body weight-independent subcutaneous low molecular weight heparin Certoparin compared with adjusted-dose intravenous unfractionated heparin in patients with proximal deep venous thrombosis

Subcutaneous body weight-adjusted low molecular weight heparin (LMWH) has been proven as effective and safe as intravenous aPTT-adjusted unfractionated heparin (UFH) for the treatment of patients with acute deep venous thrombosis (DVT). In this study we evaluate the efficacy of the initial treatment of proximal DVT with a fixed-dose, body weight-independent application of the LMWH Certoparin with a six month follow-up. In a prospective, multicentre, randomized, active-controlled study 1220 patients with objectively diagnosed proximal DVT were randomly assigned to subcutaneous 8000 U anti-factor Xa of Certoparin twice daily for 10 to 14 days or intravenous aPTT-adjusted UFH for 5 to 8 days. Both regimen were followed by oral anticoagulation for 6 months. The primary end point was the rate of symptomatic and objectively confirmed thromboembolic events within 6 months. The aim of the study was to demonstrate the non-inferiority of the Certoparin regimen as compared to UFH. The per-protocol analysis revealed 22 (3.8%) thromboembolic events in the Certoparin group and 24 (4.3%) in patients assigned to UFH within 6 months, thereby proving the non-inferiority (p<0.01), confirmed by intent-to-treat analysis (p<0.001). Major bleeding occurred in 6 and 7 patients started on Certoparin or UFH during the treatment period. Thromboembolic events were equally distributed in body weight categories with < 50, 50-80 and >80 kg as followed: 0, 3.6% and 4.1% of patients for the Certoparin group and 0, 4.6% and 4.2% of patients for the UFH group. The same was true for major bleeding complications with 0, 2.9% and 1.5% for Certoparin and 0, 3.5% and 4.2% for UFH. Overall mortality was 1.9% in the Certoparin group and 2.7% in the UFH group. Fixed-dose body weight-independent subcutaneous LMWH Certoparin is at least as efficacious and safe as intravenous aPTT-adjusted UFH for the initial treatment of acute proximal DVT. This effect is maintained during a 6-months follow-up of treatment with oral anticoagulation.