Addressing the unmet needs and challenges in managing older AF patients
A key focus in the management of atrial fibrillation (AF) in older patients is stroke prevention through oral anticoagulation. However, a significant proportion of older AF patients remain undercoagulated due to the perceived bleeding risk of oral anticoagulants (OACs). Dr Tan Vern Hsen, Senior Consultant, Department of Cardiology, Changi General Hospital, Singapore, and Dr Barbara Helen Rosario, Senior Consultant, Department of Geriatric Medicine, Changi General Hospital, Singapore, shared their respective insights into managing older AF patients for an integrated approach.
Bleeding risk over-estimated
The risk of stroke in AF patients increases with age. OAC use is central to minimizing this risk. However, frailty and multimorbidities add complexity to OAC use in older patients. Often, OACs are needlessly withheld due to overestimation of bleeding risk. Hence, there remains an unmet need in the use of OACs in older patients [Figure 1].
“Older patients, particularly those ≥80 years, are often not given
OACs as they are perceived to be at high risk for falls, frail, or have a history of bleeding or bleeding tendencies,” said Tan.
Stroke vs bleeding risk: A delicate balance
However, protecting older patients with AF is not only a matter of preventing bleeding, but also stroke. This is especially important as there is a higher risk of ischaemic cardiovascular events vs major bleeding in older patients with AF [Figure 2], with older age (>85 years) being the most important risk factor for ischaemic stroke. [Europace 2020;22:47-57]
Importantly, bleeding is reversible, whereas stroke is permanent. A delicate balance between the two requires clinicians’ assessment of risk factors and best judgment.
“Striking a balance between stroke and bleeding risk is best achieved by calculating an individual’s risk factors using the CHA2DS2-VASc* score for stroke risk, and the HAS-BLED** score for bleeding risk assessment,” said Rosario. “Both are important and warrant consideration when making treatment decisions.”
“However, a high HAS-BLED score (≥3) should not necessarily lead to withholding of OACs as its clinical benefit is still high,” added Tan. “Instead, the physician in charge should address the modifiable bleeding risk factors and ‘flag up’ the patient for regular review and follow-up.”
The marked variation in anticoagulation prescribing among Asian patients with AF (21–89%) suggests clinicians could be more proactive in offering OACs to patients. [Thromb Haemost 2017;117:2376-2388]
Improving treatment adherence
Treatment adherence, said Rosario, is critical in these patients. Hence, doctors should ask during consultations about the difficulties patients may have taking their medications. “A review of their medication history to ensure they had adequate supply between appointments and whether there have been gaps in prescribing may also identify issues.”
NOACs may be renoprotective
The combination of AF and chronic kidney disease (CKD) is also increasingly common, said Tan. “Strategies to prevent renal function decline include lifestyle modification and pharmacological treatment of the respective risk factors.”
Another important disease entity is anticoagulation-related nephropathy (ARN), a common but often underdiagnosed syndrome affecting about 20 percent of patients treated with warfarin. [Kidney Int 2011;80:181-189] “It is defined as acute kidney injury (AKI) without obvious aetiology in the setting of an INR*** >3.0. ARN can lead to new onset or progression of CKD,” Tan pointed out. ARN is suspected in warfarin-treated patients with unexplained haematuria after other potential causes of AKI have been ruled out. Treatment includes warfarin cessation and supportive management. [J Am Soc Nephrol 2011;22:1856-1862]
“The introduction of non-vitamin K oral anticoagulants (NOACs) is a game-changer in this aspect as evidence suggests that NOACs may be renoprotective in older
patients,” he added. He however cautioned that in patients with impaired renal function, the dose of NOAC may need to be adjusted [Figure 3].
NOACs in patients at risk of falls
One factor that influences physicians’ decision to anticoagulate frail older AF patients is their risk of falls, noted Rosario. Falls are not a contraindication to OAC use but precautions should be taken, and modifiable bleeding risk factors addressed. [Europace 2021;23:1612-1676] Despite the risk of traumatic intracranial haemorrhage (ICH), anticoagulation still benefits older AF patients at risk of falls [Am J Med 2005;118:612-617], and compared with vitamin K antagonists (VKAs), NOACs have been shown to have lower bleeding risk and less ICH in frail older patients. [Heart 2021;107:1376-1382]
There is some evidence suggesting reduced adverse effects with no compromise in efficacy by reducing the dose of a NOAC in certain subgroups [Intern Med J 2020;50:1359-1366; Adv Chronic Kidney Dis 2016;23:19-28; J Am Col Cardiol 2016;68:1452-1464]; however, low-dose anticoagulation has been associated with both increased bleeding and thrombotic stroke when compared to full-dose anticoagulation. [Intern Med J 2020;50:1359-1366]
“The presence of frailty should not impact guidelines recommended for NOAC dosing in older patients,” Rosario emphasized, but “individuals with severe frailty (eg, those who are in the final phase of life or palliative with advanced disease) may not benefit from anticoagulation.”
What the guidelines advise
Other than the use of OACs to prevent stroke, the 2020 ESC# guidelines advise integrated management of AF in older patients, involving multiple specialties. [Eur Heart J 2021;42:373-498]
Of note, frailty, impaired renal function, and increased risk of falls do not outweigh the benefits of OACs. “NOAC is however contraindicated in AF patients with mechanical valve or moderate-to-severe mitral stenosis,” said Tan.
The optimal use of OACs in older AF patients with multiple comorbidities (eg, dementia, kidney disease, frailty, recurrent falls, and polypharmacy) remains a challenge, said Tan. “NOACs were shown to have a superior safety profile and similar or better efficacy over warfarin in this population based on clinical trials. Physicians should use the appropriate or approved dosage for each NOAC, [and its] dose should be adjusted based on renal function.”
“Age alone should not be a deciding factor for decisions on anticoagulation, as many in their ninth decade continue to live healthy, independent lives. Where possible, offer anticoagulation to older patients with AF and risk factors for ischaemic stroke, with discussion about the risk vs benefit for each individual patient,” added Rosario.