Antikoagulaatioon

Antikoagulaatioon, or anticoagulation, refers to medical strategies that reduce the blood’s ability to clot. The goal is to prevent the formation of harmful clots and to minimize the risk of thromboembolic events such as stroke, pulmonary embolism, and deep vein thrombosis. Anticoagulants are used in conditions including atrial fibrillation, venous thromboembolism, mechanical heart valves, and after certain surgeries.

Most antikoagulants work by interfering with the coagulation cascade. They either inhibit vitamin K–dependent clotting factors or directly inhibit thrombin (factor IIa) or factor Xa. The main categories are vitamin K antagonists, direct oral anticoagulants (DOACs), and parenteral anticoagulants. Vitamin K antagonists, such as warfarin, require regular blood testing to monitor the international normalized ratio (INR). DOACs, including dabigatran, rivaroxaban, apixaban, and edoxaban, have more predictable effects and typically do not require routine INR monitoring. Parenteral anticoagulants include unfractionated heparin and low-molecular-weight heparin, often used in hospital settings or bridging therapy.

Indications for anticoagulation include prevention of stroke in atrial fibrillation, treatment of acute venous thromboembolism, and prophylaxis after certain surgeries. Choice of agent depends on patient factors such as kidney function, bleeding risk, drug interactions, and specific clinical scenarios (for example, some DOACs are not suitable for mechanical heart valves).

Safety and management emphasize bleeding risk assessment, dose adjustments, and drug interactions. Reversal strategies exist for major bleeding or urgent procedures: vitamin K and prothrombin complex concentrates for vitamin K antagonists; specific reversal agents for several DOACs, along with general supportive measures. Regular follow-up and patient education are essential to balance thrombosis and bleeding risks.