Half a million people in Germany take medication to inhibit blood clotting on a permanent basis, and another 350,000 need the drugs for a limited time. The reason: they are at increased risk of blood clots forming in their bodies and – washed away with the bloodstream – leading to strokes or vascular occlusions in other organs. “Precisely adjusted anticoagulation protects these patients from such thromboembolism and thus very often from life-threatening complications,” emphasizes Prof. Hans-Jürgen Becker, MD, Chairman of the Board of the German Heart Foundation.
Risk factors for stroke
Among the significant risk factors for strokes is the cardiac arrhythmia atrial fibrillation, especially in older age. The risk of thromboembolism is also significantly increased if the mitral valve in the heart is severely narrowed, after the insertion of a new heart valve, in the presence of certain blood clotting disorders, or if a thromboembolism has occurred in the past. Those who have received a mechanical heart valve need anticoagulant medications such as Marcumar or falithrom for life; when a biological valve is used, they are necessary for three months after surgery.
Goal: Optimal embolic protection with minimal risk of bleeding.
Anticoagulation is effective and safe only if it is precisely adjusted. This is because any underdose of anticoagulant medication carries the risk of insufficient protection against strokes or embolisms, whereas an overdose makes the blood so thin that bleeding can easily occur. To obtain optimal protection against clot formation with minimal risk of bleeding, blood clotting is adjusted to the so-called therapeutic range.
The INR value (International Normalized Ratio) is used to define this range individually for each patient. To prevent the anticoagulation from being derailed upwards or downwards, it is recommended that patients monitor the INR value regularly themselves or have it measured by a doctor once a week, but at least every 14 days. In Germany, it is often checked only every three to four weeks – an interval that must be considered too short for optimal coagulation control.
Quick value is “out”
In the past, the so-called Quick value was determined to monitor anticoagulation. This has turned out to be unsafe for patients because the measurement results of different laboratories are often not comparable. “Unfortunately, there are still some medical practices and clinics in Germany that work with the Quick value,” criticizes Prof. Becker. Patients taking Marcumar or similar drugs should make sure that their anticoagulation is only recorded with the INR value.
A major advance in coagulation monitoring is also the possibility of determining the INR value oneself after appropriate training – with a drop of blood from the fingertip and a small device that is operated similarly to a blood glucose meter. “Self-measurement of the INR value,” says Prof. Becker, “enables better, safer, more flexible and more independent control of anticoagulation. This helps to increase the effectiveness of treatment with anticoagulant drugs and reduce the risk of complications.”
A list of training centers for self-determination of anticoagulation and a special anticoagulation identification card are available free of charge from: German Heart Foundation, Vogtstr. 50, 60322 Frankfurt am Main, Germany.
