American College of Cardiology (ACC), American Heart Association (AHA) and Heart Rhythm Society (HRS) guidelines

Update your knowledge of the American recommendations regarding the use of oral anticoagulants to prevent thromboembolism in AF patients.

The guidelines from the USA recommend oral anticoagulants for AF (or atrial flutter) patients with a CHA2DS2-VASc score of two or greater in men or three or greater in women. Unless, the person has moderate-to-severe mitral stenosis or a mechanical heart valve, the guidelines remark that omitting anticoagulants is reasonable for AF patients CHA2DS2-VASc score of zero in men or one in women, but can be considered in those with scores of one and two respectively.37

The guidelines recommend DOACs rather than warfarin in eligible AF patients, with the exception of those with moderate-to-severe mitral stenosis or a mechanical heart valve. Warfarin is recommended for AF patients with mechanical heart valves. The guidelines note that the trials suggest that DOACs were non-inferior and, in some trials, superior to warfarin for preventing stroke and systemic embolism. In addition, DOACs were associated with lower risks of serious haemorrhage compared with warfarin.37

The ACC/AHA/HRS guidelines recommend the CHA2DS2-VASc score to assess stroke risk in AF patients, except people with moderate-to-severe mitral stenosis or a mechanical heart valve. The guidelines stress that the decision to use anticoagulants depends on the risk of thromboembolism, irrespective of the AF pattern and should be individualised based on shared decision-making after discussing the absolute and relative risks of stroke and haemorrhage, and the patient’s values and preferences. Clinicians and patients should periodically re-evaluate the need for an choice of anticoagulant based on the risk of stroke and haemorrhage.37

The ACC/AHA/HRS guidelines underscore the importance of regularly monitoring patients taking warfarin. The guidelines suggest determining INR at least weekly during initiation of warfarin therapy and at least monthly when anticoagulation is stable, with the INR in range. The guidelines recommend a DOAC for patients that cannot maintain a therapeutic INR with warfarin, unless the person is ineligible because of moderate-to-severe mitral stenosis or a mechanical heart valve.37

Clinicians should evaluate renal and hepatic function before starting a DOAC. The guidelines recommend re-evaluating renal and hepatic function at least annually:37

  • For AF patients with end-stage CKD, defined as creatinine clearance of less than 15 mL/minute or dialysis, and a CHA2DS2-VASc score of 2 or greater in men or 3 or greater in women, the guidelines suggest apixaban or warfarin
  • For AF patients (except those with moderate-to-severe mitral stenosis or a mechanical heart valve) and moderate-to-severe CKD and a CHA2DS2-VASc score of 2 or greater in men or 3 or greater in women, the guidelines suggest considering reduced doses of direct thrombin or factor Xa inhibitors; the definition of moderate-to-severe CKD depends on the DOAC: serum creatinine at least 1.5 mg/dL for apixaban and creatinine clearances of 15–30 mL/minute for dabigatran, at least 50 mL/ minute for rivaroxaban or 15–50 mL/ minute for edoxaban
  • The guidelines do not recommend dabigatran, rivaroxaban or edoxaban for AF patients with end-stage CKD or on dialysis as the evidence from clinical trials does not confirm that the benefit exceeds risk

Stroke prevention in patients with AF and ACS and/or PCI

US guidelines treat these patients as one specific group.37 Patients treated for ACS normally require dual antiplatelet therapy with aspirin and may also require the addition of warfarin or a DOAC (triple therapy). Double therapy (DOAC plus an antiplatelet medication without aspirin) can also be considered. Indeed, the US guidelines recommend that triple therapy is limited to 4–6 weeks as this is the period of greatest risk of thrombosis following PCI, especially in patients with ACS.37

Learn more about clinical trials in this patient population, such as the AUGUSTUS trial. With guidelines taking onboard the evidence from trials such as the AUGUSTUS trial we are moving towards harmonisation of American and European guidelines. Find out how this will improve patient treatment outcomes from Professor Robert Storey.

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