Late initiation of oral anticoagulants common after AF diagnosis
In patients diagnosed with atrial fibrillation (AF), late initiation of oral anticoagulant (OAC) therapy is common and is associated with a significantly increased risk of stroke, according to a study led by the Chinese University of Hong Kong (CUHK).
The results, reported at the European Society of Cardiology (ESC) Congress 2018, showed that 23.8 percent of patients were not prescribed OAC therapy until >12 months after the first AF diagnosis. [Sun W, et al, ESC 2018, poster P3842]
In 21.4 percent of the patients, OAC therapy was prescribed at >1–≤12 months after AF diagnosis, whereas in 54.8 percent of the patients, the diagnosis-to-prescription (Dx-to-Rx) time was ≤1 month.
The study included 12,928 consecutive patients aged ≥65 years who received AF screening at medical outpatient clinics using AliveCor, a smartphone-based handheld single-lead ECG device, between December 2014 and December 2016. AF was detected in 1,646 patients (12.7 percent; mean age, 78.2 years; mean CHA2DS2-VASc score, 4.2), of whom 199 (1.54 percent) were newly diagnosed cases. Clinical characteristics were generally comparable between patients with previously known and newly detected AF except for a significantly higher prevalence of congestive heart failure and significantly higher rates of use of aspirin, P2Y12 inhibitors and OACs among patients with previously known AF.
“Delayed OAC initiation was associated with a significantly higher rate of stroke or transient ischaemic attack [TIA], with more marked increases in patients with higher CHA2DS2-VASc scores [p<0.01],” the investigators reported.
In patients with a CHA2DS2-VASc score of ≥5, the rate of stroke/TIA was 43.48 percent in those with a Dx-to-Rx time of >12 months, 37.76 percent in those with a Dx-to-Rx time of >1–≤12 months, and 14.29 percent in those with a Dx-to-Rx time of ≤1 month.
Among patients with a CHA2DS2-VASc score of 3–4, the corresponding rate of stroke/TIA was 35.99 percent, 23.69 percent and 16.66 percent, respectively. In patients with a CHA2DS2-VASc score of 1–2, the corresponding rate of stroke/TIA was 21.7 percent, 13.42 percent and 13.65 percent, respectively.
Concomitant use of aspirin was an independent predictor of late OAC initiation (ie, Dx-to-Rx time >12 months) in the entire study cohort (odds ratio [OR], 3.35; 95 percent confidence interval [CI], 2.48 to 4.53).
In patients at high risk of stroke (ie, CHA2DS2-VASc score ≥5), history of vascular disease (OR, 1.69; 95 percent CI, 1.01 to 2.82) and absence of prior stroke/TIA (OR, 2.51; 95 percent CI, 1.48 to 4.27) were also independent predictors of late initiation of OAC therapy.
“These findings stress the importance of prompt OAC initiation after AF diagnosis for effective stroke prevention,” the investigators concluded.
In another study, investigators from the Ruttonjee Hospital and Tang Shiu Kin Hospital showed that screening for subclinical AF using AliveCor is effective and practical in specialist outpatient department settings. [Leung SC, et al, ESC 2018, poster P992]Among 2,036 patients screened (mean age, 75.3 years; mean CHA2DS2-VASc score, 3.7), 13 (0.6 percent) were newly diagnosed to have AF. There were eight (38.1 percent) false-positive cases, while 264 patients (12.9 percent) with initially uninterpretable results were confirmed to be in sinus rhythm.