International Normalized Ratio (INR), coagulation factor activities and calibrated automated thrombin generation - influence of 24 h storage at ambient temperature.

International Normalized Ratio (INR) measurements are used to monitor oral anticoagulation therapy with coumarins. Single coagulation factor activities and calibrated automated thrombin (CAT) generation are considered as more advanced methods for evaluating overall haemostatic capacity. The aims were to assess the variability of INR, coagulation factor activities, and CAT, during 24 h of storage of blood samples at ambient temperature. A total of 24 patients on stable coumarin treatment were followed prospectively for 6 weeks. INR was analyzed at 0, 6 and 24 h after blood sampling and 1-stage clotting activity of coagulation factors II, VII, IX, and X as well as CAT generation was recorded after 0 and 24 h respectively. Statistical analyses included Bland-Altman plot, 95% limits of agreement, and a variability test using a mixed effect model. The level of INR remained statistically unchanged from 0 to 6 and 24 h of storage. Coagulation factor activities and CAT revealed no significant difference induced by 24 h of storage, although the limits of agreement were wide. Patients' individual INR, coagulation factor activities, and CAT generation were not significantly influenced by 24 h storage of blood samples, but for the CAT generation analyses a trend toward time dependency was detected.

Self-management of oral anticoagulant therapy for mechanical heart valve patients.

OBJECTIVE: Self-management of oral anticoagulant therapy (OAT) has shown good results on a short-term basis. We hypothesize that self-management of OAT provides a better quality of treatment than conventional management also on a long-term basis. The aim of this study was to assess the quality of self-management of OAT in patients with mechanical heart valve prostheses on a 4-year perspective in a prospective, non-randomized study. DESIGN: Twenty-four patients with mechanical heart valves and on self-managed OAT were followed for up to 4 years. A matched, retrospectively selected group of conventionally managed heart valve patients (control group) was used as reference. RESULTS: The median observation time was 1175 days (range: 174-1428 days). The self-managed patients were within therapeutic INR target range for a mean of 78.0% (range: 36.1%-93.9%) of the time compared with 61.0% (range 37.4%-2.9%) for the control group. CONCLUSION: Self-management of OAT is a feasible and safe concept for selected patients with mechanical heart valve prostheses also on a long-term basis. It provides at least as good and most likely better quality of anticoagulant therapy than conventional management assessed by time within the therapeutic International Normalized Ratio (INR) target range.

Self-management of oral anticoagulation in children with congenital heart disease.

OBJECTIVE: The concept of self-management of oral anticoagulation has been shown to entail better quality of treatment than conventional management when assessed in selected adults. We have extended the concept of self-management to include children with congenital cardiac disease, hypothesizing self-management of oral anticoagulation is also possible in this subset of patients. Our aim was to assess the quality of self-management. METHODS: We trained 14 children aged from 2.2 to 15.6 years, with a mean age of 9.7 years, and their parents, in domiciliary analysis of the International Normalized Ratio and necessary adjustment of dosage of coumarin. The curriculum for training lasted for 27 weeks, and the patients and their parents were followed for a period of up to 31 months by weekly measurement of the values obtained for the International Normalized Ratio. RESULTS: The patients were observed over a mean of 547 days, with a range from 214 to 953 days. The patients were within the therapeutic targetted range of the International Normalized Ratio for a median of 65.5% of the time, with a range from 17.6% to 90.4%. None of the patients experienced thromboembolic or bleeding complications requiring doctoral intervention. All the patients and their parents expressed full satisfaction with the treatment. CONCLUSION: Self-management of oral anticoagulation provides a good quality of treatment, which is feasible and safe in selected children with congenital cardiac disease.