Clinical meaning
The clinician must navigate complex anticoagulation decisions across multiple clinical scenarios. DOACs (dabigatran, rivaroxaban, apixaban, edoxaban) have largely replaced warfarin for non-valvular atrial fibrillation and VTE treatment due to predictable pharmacokinetics, fewer drug-food interactions, and no routine monitoring requirement. However, warfarin remains essential for mechanical heart valves and antiphospholipid syndrome. The choice of anticoagulant depends on indication, renal function, drug interactions, bleeding risk (HAS-BLED score), and patient factors. Reversal agents are now available for most anticoagulants: protamine for heparin, vitamin K and 4-factor PCC for warfarin, idarucizumab for dabigatran, and andexanet alfa for anti-Xa inhibitors. The clinician must prescribe, monitor, adjust, and manage transitions and complications across the anticoagulation spectrum.
Diagnosis & workup
Diagnostics & workup: - Calculate CHA2DS2-VASc score to determine stroke risk and anticoagulation need - Calculate HAS-BLED score to assess bleeding risk on anticoagulation - Order baseline and serial renal function (CrCl) for DOAC dose determination - Order CBC with baseline platelet count before initiating therapy - Monitor INR for warfarin patients: target 2-3 (non-valvular AF, VTE) or 2.5-3.5 (mechanical valves) - Order DOAC-specific drug levels (anti-Xa calibrated to specific drug) only in emergencies or special populations - Screen for drug interactions: CYP3A4 and P-glycoprotein inhibitors/inducers affect DOACs