Summary. Although several authoritative, evidence-based, guidelines for the prevention of venous thromboembolism (VTE) have been published, the use of VTE prophylaxis in routine clinical practice varies markedly. Even in orthopedic surgery, the indication for which prophylaxis is used most often, a signi®cant proportion of surgeons do not use routine prophylaxis. When prophylaxis is used, guideline recommendations are often not followed. A number of factors may contribute to the under-use of guidelines. Physician-related factors include: a lack of awareness of, or familiarity with, the guidelines; a perception that VTE is not a signi®cant problem or that VTE prophylaxis is ineffective; and concern about potential bleeding risks. The guidelines may also be perceived to be too complicated or dif®cult to apply in a routine manner. In addition, a lack of facilities or resources may also present a barrier to implementation of the guidelines. A number of strategies are being investigated in an attempt to improve compliance with guidelines for VTE prophylaxis. For example, the Investigators Against Thromboembolism (INATE) initiative has developed a simpli®ed pocket guideline on VTE prophylaxis in orthopedic and trauma surgery in order to raise awareness of the current guideline recommendations.

In a prospective, randomized, assessor-blind multicentre study two antithrombotic subcutaneous regimens were compared in patients undergoing total hip replacement. Group 1 (154 patients) received 750 anti-Xa units of a new low molecular weight heparinoid (Lomoparan) subcutaneously twice a day and group 2 (155 patients) received 5000 units heparin and 0.5 mg dihydroergotamine (heparin-DHE 5000) twice a day. The incidence of deep vein thrombosis, assessed by routine bilateral venography on day 10 (+/- 1), was 17 and 32 per cent in groups 1 and 2 respectively (risk reduction 47 per cent; P = 0.007). One patient in each group developed a symptomatic pulmonary embolism confirmed by lung scanning. Major bleeding complications occurred in one patient in each group and no significant difference was observed between the two groups with respect to minor bleeding complications. Subcutaneous Lomoparan appears to be as safe as heparin-DHE 5000 at the above doses with regard to bleeding complications, and is more efficacious with respect to venous thrombosis.

Prophylaxis with low-dose heparin has contributed significantly to the reduction in thromboembolic complications in surgery. Without prophylaxis, the rate of deep-vein thrombosis is about 30% in patients undergoing general surgery, rising up to 70% in orthopedic and trauma surgery. According to Collins et al. [N Engl J Med 1988;318:1162-1172] and Clagett and Reisch [Ann Surg 1988;208:227-240] heparin prevented at least 60% of deep-vein thromboses. Meanwhile, various heparin fragments have become available for clinical use and the question arises whether these low-molecular-weight heparins are equal or even superior to unfractionated heparin in preventing thromboembolic complications. Because of the pharmacological heterogeneity of low-molecular-weight heparins and variations in administered doses, this question can only be partially answered by meta-analysis. However, in summary it can be said that despite the difficulties of and concerns about general assessments, single daily injections of low-molecular-weight heparin are at least as efficacious as multiple daily doses of unfractionated heparin. In particular, enoxaparin 40 mg once a day and enoxaparin 30 mg twice a day seem to be superior to unfractionated heparin in high-risk patients, and adverse drug reactions occur less frequently when this prophylaxis is used.

Summary215 German family physicians participated in a prospective registry to assess the venous thromboembolic risk in acutely ill medical outpatients. In 1247 patients who were visited at home due to an acute medical illness, the risk factors were documented using a standardised questionnaire. The doctors subjectively rated the patient’s risk on a scale ranging from 1 to 10 and the result was compared with an objective risk-score which had been previously developed for hospitalized patients and has been successfully used in these patients. The results showed a wide agreement of the subjective risk assessment and the objective score. The resulting consequence of an adequate thromboprophylaxis reflects a high awareness of venous thromboembolic risk among the physicians treating acutely ill medical outpatients.

In the case of clinically minor bleedings, a delay in the administration of the next dabigatran etexilate dose is recommended. The length of the delay is based on the patient's individual thromboembolic risk. In minor bleedings the use of prothrombin complex concentrates is not indicated. In the case of moderate or major bleedings the main focus should be on stabilising the circulation by using fluids and blood products and, if a lesion can be identified, the local treatment thereof. If time and infrastructure is available, dialysis offers an effective and fast option to remove dabigatran out of the circulation. In the incidence of severe and life threatening bleedings, an additional, more complex haemostasis management is required. Besides haemodynamic stabilisation of the circulation, administration of prothrombin complex concentrates should not be delayed. It has to be kept in mind that standard laboratory coagulation parameters may not accurately reflect the effect of prothrombin complex concentrates in patients on dabigatran. Hence the effect of the prothrombin complex concentrate should be monitored clinically and adjusted by means of onset of coagulation in vivo.