Therapeutic target values in oral anticoagulation--justification of Dutch policy and a warning against the so-called moderate-intensity regimens.

Careful scrutiny of relevant thrombosis prevention studies in the light of recent knowledge on the responsiveness to the anticoagulant defect of the various prothrombin time assays used in these studies casts serious doubts on the adequacy of the so-called moderate-intensity warfarin regimens, currently recommended by British and North American experts, in the majority of clinical situations. As long as there is strict laboratory monitoring, more intensive anticoagulation provides satisfactory prevention of thromboembolic events. The Federation of Dutch Thrombosis Centers recommends a target of 3.0 International Normalized Ratio (INR) for the primary and secondary prevention of venous thrombosis and thromboembolism, 3.5 INR in case of recurrence under the former regimen and for patients at risk for a cardiogenic embolism from any source (including tissue heart valve replacement) and those with atherothrombotic disease, and 4.0 INR for patients with a mechanical heart valve prosthesis. The risk of hemorrhage at such levels of anticoagulation remains acceptable.

Long-term stability of international reference preparations for thromboplastins.

Three certified reference materials for thromboplastins are available from the Community Bureau of Reference (BCR) of the European Commission for calibration of commercial thromboplastins used for control of oral anticoagulant therapy. The long-term stability of these reference materials has been monitored by two independent laboratories, using deep-frozen and lyophilized plasma samples. Prothrombin times and prothrombin time ratios measured on 19 occasions in the period 1981-86 have been analysed for trend with time. Although significant trends of prothrombin time and ratio (P less than 0.05) were observed, a consistent pattern of trends could not be recognized. The significant trends of prothrombin time and prothrombin time ratio are most probably due to changes in local laboratory conditions. There is no indication that the reference materials have deteriorated since the beginning of the study. It is recommended that long-term stability monitoring of thromboplastins be performed by at least two laboratories simultaneously.

[Fibrinolytic and anticoagulation therapy in Budd-Chiari syndrome. Review and recommendations]. / Fibrinolytische und Antikoagulantientherapie beim Budd-Chiari-Syndrom. Ubersicht und Empfehlungen.

In Western countries, hepatic vein thrombosis (Budd-Chiari syndrome) is, as a rule, an uncommon though well-known complication of acquired or hereditary thrombophilia. It may be complicated by overt defibrination when secondary to deep venous thrombosis ascending to the vena cava. To be effective treatment should consist of early initial intensive thrombolysis for up to one week, followed without interruption by an APTT-controlled heparin infusion. Oral anticoagulant therapy is started together with the heparin, which should not be discontinued until the prothrombin times, expressed as international normalized ratios (INR), lie within a therapeutic range of 3-5 INR for 2 days, the target being 4 INR. After this intensity of anticoagulation has been maintained for three weeks, the range may be lowered to 2.5-4 INR, the target being 3 INR. Oral anticoagulation should be continued for as long as thrombophilia persists.