100,000 patients in Belgium (1% of the total population) are currently treated with an oral anticoagulant agent, mainly phenprocoumone and acenocoumarol. In the absence of a network of well-organised anticoagulation clinics, monitoring of oral anticoagulant therapy (OAT) is widely performed by general practitioners or by specialists in biochemistry working in hospitals or in private laboratories. Adaptation of the vitamin K antagonists (VKA) dosages is most of the time purely intuitive and not guided by validated algorithms.

In order to improve the quality of oral anticoagulation monitoring, an anticoagulation clinic was set up by Professors Cedric Hermans and Véronique Deneys at the Cliniques universitaires Saint-Luc, Brussels in 2001. The staff is composed of one secretary and one nurse working under the supervision of the haemostasis and thrombosis specialist. Since its introduction, this clinic has been operating as described hereafter. Venous citrated blood withdrawn by the nurse in the consultation room is sent to the central laboratory.

The INR is measured on a CA7000 from Dade Behring using the Innovin as thromboplastin. Adaptation of the VKA dosing is performed with the Dawn AC (version 6.0) by the registrar or the laboratory specialist in charge. The INR result, the suggested dosing and timing of the next appointment suggested by the DAWN software are recorded in the anticoagulation log-book which is sent back by post to the patient. The anticoagulation clinic operates three days a week between 8 and 12 AM and is currently following 350 different patients.

Over the last few years, this mode of functioning has proven to be time and staff consuming. Moreover, the structure was found to be less efficient than initially expected. Several sources of errors were indeed identified among which misunderstanding by the patients of the INR result and the treatment recommendations, discrepancies between the data recorded in the logbook and the software, delay in informing the patients, loss of the log-book. In order to improve the efficiency of the structure, a Point of Care Testing (POCT) of the INR was recently introduced.

Two different POCT systems (Coagucheck XS Plus, Roche and the INRatio, Goffin Meyvis) were tested and compared with the INR results obtained with the CA7000. The correlation with the INR measured centrally was better with the Coagucheck XS Plus (figure 1) that was selected to monitor OAT at the anticoagulation clinic. The introduction of the POCT in the anticoagulation clinic was rapidly found to have several advantages: rapid measurement of the INR, immediate release of the log-book to the patient who was better informed, reduction of potential sources of errors, increased cost-effectiveness. In our experience, POCT represents a useful adjunct to the DAWN AC Software and provides a useful tool to improve the cost-effectiveness and the efficiency of anticoagulation clinic.

Figure 1. Correlation study between CA7000 (Dade Behring) and Coagucheck XS Plus (Roche)

Figure 2. Correlation study between CA7000 (Dade Behring) and INRatio (Goffin Meyvis)

Another huge problem of the anticoagulation clinic in Belgium is the interaction with the General Practitioners. There are 11,800 GP in Belgium. Majority of them are self-employed and paid by consultations. Oral Anticoagulant Treatment (OAT) treatment represents 3,600,000 consultations each year and it represents 25 consultations per GP per month. For that reason, and despite the proven effectiveness of the anticoagulation clinics, GP do not agree to refer their OAT treated patients to our consultations.

In conclusion, we can say that we have improved the security of the clinic using POCT system. We must now improve the interaction between the GP’s and the Anticoagulation Clinic.