Applying the Grades of Recommendation for Antithrombotic and Thrombolytic Therapy

Venous Thromboembolism Prevention in Acutely Ill Nonsurgical Patients

OBJECTIVE

To review recent advances in the prevention of venous thromboembolism (VTE) in acutely ill nonsurgical inpatients.

DATA SOURCES

A MEDLINE search (1966–March 2005) was done to identify relevant articles relating to prevention of VTE in acutely ill nonsurgical inpatients.

STUDY SELECTION AND DATA EXTRACTION

Four major prophylaxis trials, one registry, one guideline, and supporting articles representative of the subject matter from the last few years were included.

DATA SYNTHESIS

Enoxaparin, dalteparin, fondaparinux, and unfractionated heparin 5000 units every 8 hours are effective in reducing the risk of VTE in acutely ill medical patients, but such prophylaxis is currently underused. Barriers to be overcome include recognition of the importance of VTE in this population, definition of the optimal strategy to assess risks, optimal timing of the risk assessment, optimal prophylactic regimen for a given level of risk or disease state, and optimal duration of prophylaxis. We recommend that acutely ill medical inpatients should be risk-stratified early in their hospitalization. At this time, the specific risk-assessment protocol should be derived from the trial(s) of the available formulary agent(s). Decisions about providing prophylaxis must also be made considering anticoagulant contraindications and renal function. Mechanical methods of prophylaxis should be considered as monotherapy only if an anticoagulant contraindication exists. The optimal duration of prophylaxis is not known, but 14 days was used in recent studies.

CONCLUSIONS

Prophylaxis of VTE in acutely ill medical inpatients is underused. Data provide some guidance for increasing awareness and optimizing patient care.

In pursuit of evidence-based treatments for paediatric stroke: the UK and Chest guidelines

BACKGROUND

Arterial ischaemic stroke and cerebral sinovenous thrombosis are increasingly seen in infants and children. Incidence ranges from two to six per 100,000 children a year. Adverse outcome including death, neurological deficits, and reduced quality of life affect most children with stroke. Residual neurological deficits last many decades, for the rest of a patient's life. Of major concern is the risk of recurrent stroke, which affects up to 25% of children who have arterial ischaemic stroke after the newborn period. Children with ischaemic stroke are empirically treated with antithrombotics including antiplatelet (aspirin and clopidogrel) and anticoagulant (heparins and warfarin) drugs. No randomised controlled trials have been done besides those in patients with sickle-cell disease and adult trial data are not directly applicable to paediatric stroke due to maturational differences in coagulation and vascular systems as well as different stroke mechanisms.

RECENT DEVELOPMENTS

National and international networks of clinical and basic researchers focused on paediatric stroke are now developing. Recently published cohort and case-controlled studies are elucidating stroke mechanisms, outcomes, and treatment safety in children. Two sets of guidelines have been published in the past 6 months. These guidelines differ both in the scope of treatments and subgroups of patients with stroke they cover; however, both focus on ischaemic stroke beyond the newborn period. There are areas of agreement-for children with sickle-cell disease and stroke, both guidelines recommend initial and maintenance transfusion therapy to reduce the proportion of sickle-cell haemoglobin to less than 30%. For children with sinovenous thrombosis or arterial stroke due to dissection or cardiac embolism, both guidelines recommend anticoagulant therapy with warfarin or low molecular weight heparin for 3-6 months. However, the guidelines diverge in their recommendations for the initial treatment of non-haemorrhagic arterial ischaemic stroke, one recommending aspirin and the other 5-7 days of anticoagulants. The guidelines also differ in their recommendations for long-term treatment of children after arterial ischaemic stroke, one set recommending maintenance aspirin in all patients and the other only in children with vasculopathy. These differences arise from both a lack of sufficient evidence and the differing views of neurologists and haematologists in the treatment of paediatric cerebral thrombosis. WHERE NEXT?: Multicentre studies and networks provide increasingly precise data regarding mechanisms, outcomes, and treatment safety in paediatric stroke. These data and networks will enable clinical trials to address areas of divergent opinion and improve the outcome from childhood stroke in the near future.

[Low molecular weight heparin in patients undergoing vascular surgery]

OBJECTIVES

Despite the fact that there are no approved indications by the French regulatory agency and despite the absence of recommendations, low molecular weight heparins (LMWH) are frequently used in vascular surgery, an area at both high risk of perioperative arterial and venous thrombosis as well as of bleeding. The aim of this study was to investigate medical practice in vascular surgery, using a survey of prescribers of antithrombotic agents.

STUDY DESIGN

Survey of physicians from different specialities involved in patient care before, during, and after vascular surgery.

PATIENTS AND METHODS

Between March and June 2003, 301 physicians filled a questionnaire providing information about their antithrombotic regimens depending on the type of vascular surgery. These physicians are involved in an important part of vascular surgery activity in France.

RESULTS

The survey confirmed the use of LMWH in near 80% of patients scheduled for vascular surgery. The prescribed LMWH is frequently associated with antiplatelets agents. During patient's hospitalization, LMWH prescription is guided by numerous factors, making the prescription protocol rather complex. Major risk factors favoring continued prophylaxis after patient's hospital discharge include surgery with a high risk of thromboembolic events and limited ambulation. Analysis of the data also showed that the surgeon and the referring physician are both implicated in the majority of the postoperative care following patient's discharge, and therefore, in prescribing the antithrombotic drug.

CONCLUSION

This survey gives information on practical use of LMWH in the vascular surgery setting. This information could lead to prospective studies of LMWH in situations other than venous thromboembolic disease.

Antithrombotic and Thrombolytic Therapy: From Evidence to Application

This chapter about implementation strategies for practice guidelines is part of the 7th ACCP Conference on Antithrombotic and Thrombolytic Therapy: Evidence Based Guidelines. Grade 1 recommendations are strong and indicate that the benefits do, or do not, outweigh risks, burden, and costs. Grade 2 suggests that feasibility, acceptability and cost related to implementation strategies may lead to different choices depending on the practice setting (for a full understanding of the grading see Guyatt et al, CHEST 2004; 126:179S-187S). To encourage uptake of guidelines to reduce thrombosis, we recommend that appreciable resources be devoted to distribution of educational material (Grade 2B). We suggest that few resources be devoted to educational meetings (Grade 2B), to audit and feedback (Grade 2B), or to educational outreach visits (Grade 2B) to encourage uptake of the guidelines. We suggest that appreciable resources be devoted to computer reminders (Grade 2A) and to patient-mediated interventions (Grade 2B) to encourage uptake of the guidelines. This review suggests that there are few implementation strategies that are of unequivocal, consistent benefit, and that are clearly and consistently worth resource investment. Fully informed decisions will require additional research to identify effective guideline implementation strategies to optimize antithrombotic and thrombolytic therapy.

Methodology for Guideline Development for the Seventh American College of Chest Physicians Conference on Antithrombotic and Thrombolytic Therapy

This article describes the methodology for the Seventh American College of Chest Physicians (ACCP) Conference on Antithrombotic and Thrombolytic Therapy: Evidence-Based Guidelines. Guideline authors began by specifying the population, the intervention and alternative, and the outcomes for each clinical question, and defined the criteria for eligible articles, including methodological criteria, for each recommendation. Librarians, in collaboration with guideline authors and methodologists, conducted systematic searches for evidence. Guideline authors systematically evaluated the evidence, considered the full range of benefits, risks, inconvenience, and costs associated with alternative management strategies, considered patients' underlying values and preferences, and made recommendations accordingly. To increase the likelihood that the recommendations adequately represent patient values and preferences, the development process included a review of recommendations by research methodologists, practicing generalists, and specialists. Chapters are organized so that evidence is clearly linked to the relevant recommendations, and that recommendations particularly sensitive to underlying values and preferences are explicitly identified. Authors paid careful attention to the strength of the underlying evidence and to the balance between risks and benefits, which are both reflected in the grades of recommendations. Thus, improvements to the process of making recommendations for the ACCP guidelines include the explicit definition of questions, transparent eligibility criteria for including studies, and the specification of values and preferences underlying recommendations where they are particularly relevant. In combination with our previous practice of grading recommendations according to their strength, and the methodological quality of the supporting studies, these innovations establish our guidelines as, by and large, evidence based.