GP cardiovascular specialists Professor Ahmet Fuat and Dr Paul Ferenc answer key questions on the management of anticoagulation in general practice
- DOACs are the preferred choice of anticoagulant in NVAF
- Warfarin is still indicated in patients with mechanical heart valves, moderate to severe mitral stenosis, antiphospholipid syndrome, if CrCl <15ml/min and if the INR target is outside the usual range
- When switching from warfarin to a DOAC, the INR should be checked on the day warfarin is stopped and the DOAC started that day, over the next two days, or after further INR checks, depending on the result
- Monitoring of DOACs involves at least annual FBC and renal and liver function tests
- For most patients, the risk of bleeding with anticoagulation is outweighed by the benefits of treatment
- NSAIDs should be avoided with both warfarin and DOACs
Q When might warfarin be the anticoagulant of choice instead of a direct-acting oral anticoagulant (DOAC)?
A In the latest NICE guidelines on atrial fibrillation (AF), DOACs are the preferred choice if anticoagulation is indicated.1 NICE recommends we offer anticoagulation with a DOAC to adults with non-valvular AF (NVAF) and a CHA2DS2-VASc score of 2 or above, and consider anticoagulation with a DOAC in men with AF and a CHA2DS2-VASc score of 1, taking into account the risk of bleeding.
There are certain groups in which a vitamin K antagonist (such as warfarin) is still indicated. This includes patients with mechanical heart valves (those with bioprosthetic heart valves do not require anticoagulation unless there are other factors), moderate to severe mitral stenosis (usually due to rheumatic fever) and antiphospholipid syndrome. In addition, as renal clearance accounts for the majority of total DOAC clearance, warfarin is preferred if the creatinine clearance (CrCl) is less than 15ml/min. DOACs are also contraindicated in patients planning pregnancy, or who are pregnant or breastfeeding.
Warfarin is still recommended if the INR target is outside the usual range of 2-3, such as for patients with recurrence of deep vein thrombosis (DVT) or pulmonary embolism (PE) while receiving anticoagulation with an INR greater than 2, and advice should be sought from the specialist team in patients with venous thrombosis at unusual sites, a left ventricular thrombus or more unusual conditions such as non-compaction cardiomyopathy, as there are limited data in these conditions. Patients with active malignancy or on chemotherapy, or on certain medications including some antiepileptics, antiretrovirals and antivirals, should also be discussed with their specialist.
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Professor Ahmet Fuat is a GPSI in cardiology and honorary professor of primary care cardiology at Durham University, and Dr Paul Ferenc is a GP and PCN cardiovascular disease lead. Both are Primary Care Cardiovascular Society council members