下肢深静脉血栓形成的预防性治疗与护理

目的 评价对具有下肢深静脉血栓形成的高危因素患者进行恰当的预防性治疗与护理的临床意义。方法 对近期医学文献进行回顾性分析总结。结果 随着诊断技术的提高,临床发现住院患者中下肢深静脉血栓形成的发病率逐渐升高,特别是具有各种高危因素的患者。下肢深静脉血栓形成可导致深静脉血栓后综合征,给患者带来痛苦,严重者可发生肺栓塞,危及患者生命。近年来,低剂量肝素和小分子量肝素的应用安全、有效,对下肢深静脉血栓形成预防性治疗具有重要作用。结论 对于具有高危因素的患者,应加强护理,做好深静脉血栓形成的早期诊断及预防性治疗,避免严重并发症的发生。     

Efficacy of unfractionated heparin for thromboembolism prophylaxis in medical patients

A common mode of deep vein thrombosis prophylaxis in medical inpatients is unfractionated heparin 5000 U subcutaneously (s.q.) twice daily. We examined the evidence in favor of using this dose of heparin in this group of patients. MEDLINE was searched for studies using the words deep vein thrombosis prophylaxis and heparin. All randomized controlled trials comparing heparin and placebo or heparin and a low molecular weight heparin were used. Relative risk was 0.4 (95% confidence interval 0.22-0.73) in studies comparing heparin 5000 U s.q. b.i.d. with placebo. Relative risk was 0.28 (95% confidence interval 0.21-0.38) in studies comparing heparin 5000 units s.q. t.i.d. versus placebo. In studies comparing unfractionated heparin with enoxaparin relative risk was 1.42 (95% confidence interval 0.99-2.05). Heparin 5000 U s.q. b.i.d. is less efficacious than low molecular weight heparins and unfractionated heparin 5000 U s.q. t.i.d.     

Evaluation of the risk of venous thromboembolism in the medical patients

The venous thromboembolic risk seems to be demonstrated in medical patients since the incidence of symptomatic and asymptomatic deep vein thrombosis (DVT) without any prophylactic methods is respectively about 50 per cent in stroke, 25 per cent in acute myocardial infarction (AMI) and 15 per cent in internal medicine. A synthesis of clinical trials performed in medical patients shows that prophylactic doses of heparins (unfractionated heparin or low molecular weight heparins) reduce the incidence of DVT by 40 to 60 per cent compared with the lack of any antithrombotic agents but without any significant effect on total mortality. Other antithrombotic agents such as antiplatelet agents seem to reduce the incidence of DVT by about 40 per cent associated with a significant decrease in total mortality of stroke or AMI. But the recommendations made on the basis of these results have to be extremely cautious since the number of medical patients included in clinical trials is quite limited compared with the surgical area. Moreover, each of these recommendations is not sufficiently proven. Thus more clinical trials have to be carried out with a placebo control group in internal medicine and an aspirin control group for stroke and AMI.     

低分子肝素钙围术期应用预防老年髋部骨折术后深静脉血栓疗效观察

目的：为观察低分子肝素钙（low molecular weight heparins calcium injection,LMWH）围术期应用预防老年髋部骨折术后深静脉血栓（deep venous thrombosis,DVT）的疗效和安全性。方法：将50例接受手术的患者随机分为2组,每组25例。A组应用低分子肝素钙预防,B组运用普通血管活性药物,术后14～20d患侧下肢行彩超检查了解深静脉血栓发生情况。结果：A组0例（0%）发生深静脉血栓,B组为6例（24%）,两组比较差异有统计学意义（P〈0.05）;A组出血量（295±80）ml,B组（272±80）ml,两组比较差别无统计学意义（P〉0.05）,两组均未发生明显大出血。结论：表明低分子肝素钙围术期应用可安全有效预防下肢骨折术后深静脉血栓形成。     

Antithrombotics in thrombosis and cancer

Many cancer patients have a hypercoagulable state, with recurrent thrombosis due to the impact of cancer cells and chemotherapy or radiotherapy on the coagulation cascade. Studies have demonstrated that unfractionated heparin (UFH) or its low molecular weight fractions interfere with various processes involved in tumour growth and metastasis. These include fibrin formation; binding of heparin to angiogenic growth factors, such as basic fibroblast growth factor (FGF2) and vascular endothelial growth factor (VEGF); modulation of tissue factor; and perhaps other more important modulatory mechanisms, such as enhanced tissue factor pathway inhibitor (TFPI) release and inhibition of various matrix-degrading enzymes. Clinical trials have suggested a clinically relevant effect of low molecular weight heparin (LMWH), as compared to UFH, on the survival of cancer patients with deep vein thrombosis. Similarly, the impact of warfarin on the survival of cancer patients with thromboembolic disorders was demonstrated. Studies from our laboratory demonstrated a significant role for LMWH, warfarin, anti-VIIa, and LMWH-releasable TFPI on the regulation of angiogenesis, tumour growth, and tumour metastasis. Thus, modulation of tissue factor/VIIa non-coagulant activities by LMWH, warfarin, anti-VIIa, or TFPI might be a useful therapeutic method for the inhibition of angiogenesis associated with human tumour growth and metastasis. Additionally, antiplatelet drugs could have an impact on tumour metastasis, and the combination of antiplatelets and anticoagulants at adjusted doses might provide greater benefits to cancer patients.     

Prevention of thromboembolic risk in spinal cord injury: results of a questionnaire concerning short- and long-term treatment]

INTRODUCTION: The use of medications to prevent thromboembolic risk is recommended in spinal cord injury patients during the early phase, but there is no consensus on treatment duration and modalities. Differences in practice include choice of medication (heparin, low molecular weight heparin, inhibitors of platelet aggregation), treatment duration (three to six months or more), and criteria for discontinuation of treatment. GOALS: To determine usual practice modalities for prophylaxis of deep vein thrombosis in spinal cord injury patients, and to identify determinant criteria. METHODS: Postal survey of physiatrists taking care of spinal cord injury patients. The questionnaire asks the physician about his usual practice modalities (choice of treatments, paraclinical tests, use of compressive stockings, during and after the first six months and criteria for discontinuation of treatments). RESULTS: Forty-two questionnaires were suitable for analysis. Results show that usual practice modalities combine venous doppler testing only in the setting of suggestive clinical signs, treatment with low molecular weight heparin during three to six months, and combination with compressive stockings. DISCUSSION: Despite the absence of consensus on this question, our results are consistent with data from the literature, which identify acute spinal cord lesions as a factor of high risk for deep vein thrombosis. The risk decreases during the chronic phase. Adjuvant techniques include mobilisation, elastic compression, and standing. A study of long-term treatment modalities after deep vein thrombosis would be needed.     

The use of low molecular weight heparins for postsurgical deep vein thrombosis prevention in orthopaedic patients

The prophylactic antithrombotic efficacy of a low molecular weight heparin was compared with a traditional unfractionated calcium heparin after orthopaedic surgery in 140 patients. Deep vein thromboses were detected in legs either by Doppler sonography or [125I]fibrinogen uptake tests in five (7.1%) and seven (10%) patients, respectively. The capacity of both drugs to prevent deep vein thrombosis was demonstrated. Compared with the control group, those who used low molecular weight heparin showed a significant increase of activated factor X inhibition and smaller increases in activated partial thromboplastin times. Tolerability of both drugs was good, with a low incidence of local side-effects.     

缺血性卒中的抗凝治疗

几个大规模、多中心、随机试验发现,天然肝素(UFH)或低分子肝素(LMWH)并不能改善急性缺血性卒中患者的总体预后。紧急抗凝可预防长期卧床急性缺血性卒中患者深静脉血栓的形成。伴房颤及附加危险因素,如附壁血栓和(或)新发心肌梗死的心源性栓塞性卒中患者具有较高复发性卒中危险,若无显著出血可紧急抗凝。华法令抗凝可作为伴心房纤颤卒中患者的初级和二级预防。颅内静脉窦栓塞形成、颈动脉夹层和抗磷脂抗体综合征患者可常规抗凝,而非心源性栓塞性卒中或症状性颅内动脉狭窄综合征患者长期抗凝治疗证据不足。     

Deep vein thrombosis of the legs: new therapy by means of low molecular weight heparins

This open controlled study compared the effects of subcutaneous administration of two types of heparin in two groups of 40 patients each with deep vein thrombosis. One group received calcium heparin and the other received low molecular weight heparin for 40 days in each case. Patients receiving low molecular weight heparin showed a greater increase in inhibition of activated factor X than those receiving calcium heparin. Both drugs slightly reduced activated partial thromboplastin time. No patient experienced pulmonary embolism during the study. At the end of the study, maximum venous outflow was significantly higher in patients given low molecular weight heparin than in those given calcium heparin. No major side-effects were observed. This study showed that: (a) the anti-thrombotic effect of low molecular weight heparin was greater than for calcium heparin; and (b) low molecular weight heparin improved maximum venous outflow in approximately half of the patients, possibly by promoting or accelerating recanalization of the vessel.     

The importance of appropriate prophylaxis for the prevention of venous thromboembolism in at‐risk medical patients

Background: Venous thromboembolism (VTE), which encompasses both deep‐vein thrombosis and pulmonary embolism, is a significant healthcare problem, leading to considerable morbidity, mortality and resource utilisation. Aims: This review discusses the adherence to VTE guideline recommendations and the available clinical evidence on the appropriate type, dose and duration of VTE prophylaxis. Methods: A literature survey was conducted using Pub Med and EMBASE to identify publications related to appropriate thromboprophylaxis in medically ill patients at risk of VTE. Results: Despite evidence from clinical trials and national guidelines, VTE prophylaxis in medically ill patients remains underutilised. The use of unfractionated heparin three‐times‐daily, low‐molecular‐weight heparin once‐daily and fondaparinux once‐daily has demonstrated effectiveness in clinical trials of medically ill patients. However, controversy exists about the use of unfractionated heparin twice‐daily, and fondaparinux has not yet received US Food and Drug Administration approval for VTE prophylaxis in medically ill patients. Conclusion: It is important for clinicians to have an understanding of the evidence‐based literature when selecting an appropriate drug, at the appropriate dose, for the appropriate duration for VTE prophylaxis in medically ill patients. VTE prophylaxis in medically ill patients is cost‐effective, and drugs that are expensive may still be cost‐effective when considering improved efficacy and/or safety. Recently, the underutilisation of VTE prophylaxis has led to the involvement of government and other regulatory agencies in an attempt to increase appropriate VTE prophylaxis in US hospitals and improve the clinical and economic outcomes in medical patients at risk of VTE.     

Venous thromboembolism prevention post neck of femur fractures – does it make a difference?

Peripheral blood eosinophilia and vascular occlusions are rare occurrences in patients with pleural mesothelioma whereas eosinophilia may associate with thrombosis. We describe a patient with mesothelioma who developed peripheral blood eosinophilia followed by deep vein thrombosis despite being on low molecular weight heparin prophylaxis. We discuss the genesis of peripheral blood eosinophilia and thrombosis in pleural mesothelioma.     

股骨颈骨折后伴下肢深静脉血栓形成的治疗探讨

目的 探讨股骨颈骨折后伴下肢深静脉血栓形成的最佳治疗方法 .方法 51例患者随机分为A组(26例)和B组(25例).A组患者给予手背静脉滴注尿激酶和丹参注射液;B组患者给予手背静脉滴注丹参注射液,尿激酶于患肢股深静脉远端、在超声引导下置管滴注,并给予皮下注射低分子肝素钙,口服肠溶阿司匹林.结果 A组病例平均疗程(13....     

A clinical pathway for deep vein thrombosis

The use of low molecular weight heparin to treat deep vein thrombosis at home represents a relatively new patient population for home care agencies. Use of a clinical pathway provides a framework for defining expected outcomes of care and direction for patient assessment, care, monitoring, and documentation. Implementation and evaluation of a clinical pathway are described.     

Role of heparin and low-molecular-weight heparins in the management of acute ischemic stroke

The numerous large-scale randomized clinical trials performed during the last decade on either unfractionated heparin, or low molecular weight heparin have not been able to demonstrate undisputed benefits in patients with acute ischemic stroke, compared with no treatment or aspirin. However, a large number of these trials, including the International Stroke Trial and Chinese Acute Stroke Trial, exhibit severe methodological limitations and need to be interpreted with caution. Knowledge of thromboembolism pathophysiology and clinical experience leads to the theory that heparins will prevent red thrombus formation, propagation and embolism. Heparins effectively prevent venous thrombosis and pulmonary embolism. More trials are needed to test heparins in patients whose cardiocerebrovascular lesions are better defined by newer neuroimaging techniques. The efficacy of heparins has not been adequately tested in patients with defined stroke subtypes and occlusive vascular lesions. Heparins should not be indiscriminately given to all patients with acute ischemic stroke. High-quality, randomized trials that adequately study heparin use in patients using modern technology for vascular lesions and stroke subtypes are lacking, and need to be performed.     

Nurse-led outpatient treatment of deep vein thrombosis

Patients with a deep vein thrombosis (DVT) have, historically, been treated initially with intravenous, unfractionated heparin, necessitating inpatient care. The advent of low molecular weight heparin (LMWH) now allows treatment of these patients on an outpatient basis, as the authors explain here.     

Unresolved issues in anticoagulant therapy

Summary. Large randomized clinical trials have clarified some issues of anticoagulation and have led to progress, such as outpatient treatment of acute deep vein thrombosis with low‐molecular‐weight heparin. However, many uncertainties remain and are reviewed here. When should thrombolytic therapy be used, apart from patients in shock due to pulmonary embolism? How should low‐molecular‐weight heparin be used in patients with extreme obesity or renal failure? The optimal duration of anticoagulation after venous thromboembolism has been the subject of many debates. With the recognition of an increasing number of risk factors for recurrence, the picture becomes increasingly complex. Lower intensity of anticoagulation with vitamin K antagonists and novel anticoagulant drugs are possible alternatives in extended secondary prophylaxis. For stroke prophylaxis in non‐valvular atrial fibrillation, there is a gray zone between the groups where there is a clear indication for aspirin or for vitamin K antagonists. Anticoagulation in connection with cardioversion raises questions regarding optimal postprocedure therapy. Fine tuning of prophylaxis against thromboembolism in patients with prosthetic heart valves requires more studies of subgroups, homogenous for position and type of valve as well as presence of atrial fibrillation. The management of these patients in case of surgical procedures has not been studied properly. Secondary prophylaxis after myocardial infarction may achieve the best effect with vitamin K antagonists at an INR of 2.0–2.5 in combination with low‐dose aspirin, but is it really cost‐effective? Finally, many controversies exist regarding anticoagulation during pregnancy.     

Treatment of upper limb deep vein thrombosis with low molecular weight heparin

Upper limb deep vein thrombosis has been an under-recognized disease; however, physicians' awareness of it as a cause of arm pain and edema is increasing. Previously thought of as benign, upper limb deep vein thrombosis has been shown in recent studies to pose a significant risk for pulmonary embolus and death. The need for treatment is now recognized; however, effective treatments for upper limb deep vein thrombosis have not been fully defined. Anticoagulation with oral agents is known to be successful in preventing complications and recurrence. This report presents the first case of upper limb deep vein thrombosis successfully treated with only low molecular weight heparin.     

Fondaparinux (Arixtra): a new anticoagulant

Fondaparinux is a promising new antithrombotic agent. This pentasaccharide selectively and specifically inhibits coagulation factor Xa, and requires antithrombin as co-factor It is entirely synthetic, in contrast to conventional heparin and low molecular heparins which are derived from animal tissues. Fondaparinux exhibits a high bioavailability and is convenient to use as it only needs to be given once daily by subcutaneous injection. Peak plasma levels are achieved within two hours of dosing and the plasma half-life of fondaparinux is approximately 17 hours. There is no specific antidote for fondaparinux: it is not neutralised by protamine sulphate. Fondaparinux shows no cross-reactivity with antibodies associated with heparin-induced thrombocytopenia. Several randomised, double-blind studies have demonstrated superiority with respect to a low molecular weight heparin (enoxaparin) in preventing venous thromboembolism in the setting of orthopaedic surgery. The results of clinical trials of fondaparinux in the treatment of deep vein thrombosis and acute coronary syndrome are also presented.     

Heparin-induced platelet aggregation in anorexia nervosa and in severe peripheral vascular disease

Abstract. We have previously demonstrated that platelets obtained from patients with anorexia nervosa or severe peripheral vascular disease are hyperaggregable. Since conventional heparins are known to activate platelets in vitro and occasionally induce thrombosis and consumptive thrombocytopenia in vivo , we have investigated the direct effect of a conventional heparin on platelets obtained from patients with anorexia nervosa or severe peripheral vascular disease. Heparin at therapeutic concentrations was found to induce platelet aggregation of such platelets in vitro. In contrast, a recently developed low molecular weight heparinoid (Org 10172), at therapeutic concentrations, had no effect on these hyperaggregable platelets. We conclude that: (i) heparin may be potentially harmful to patients with hyperaggregable platelets; (ii) thrombocytopenia and thrombosis associated with heparin therapy may be mediated through a direct effect of heparin on platelets; (iii) it is unlikely that heparin induced thrombocytopenia is always mediated by classical immunological mechanisms, especially in patients with hyperaggregable platelets; and (iv) low molecular weight heparinoids may be safer anticoagulants in patients with platelet hyperaggregability.     

Deep vein thrombosis and anticoagulant therapy.

This article focuses on deep vein thrombosis (DVT) and anticoagulant therapy. The risk factors, pathophysiology, prevention, and detection of DVT are explained. Anticoagulants such as unfractionated heparin (UFH), low molecular weight heparin (enoxaparin), and warfarin are discussed. The article also reviews nursing assessment and monitoring of patients with DVT as well as patient education on anticoagulants.