When to Initiate Dabigatran Therapy in Patients with Atrial Fibrillation After First Ischemic Stroke?

Study Methodology and Population

Based on data from 2014–2018, a total of 1489 patients (53% women; average age 75 years) with non-valvular atrial fibrillation were included in the study from the SITS registry (Safe Implementation of Treatment in Stroke). All patients were hospitalized for their first acute iCMP, treated with intravenous thrombolysis (alteplase) and/or endovascular thrombectomy, and within 3 months, anticoagulant therapy with dabigatran was initiated as secondary iCMP prevention.

Before hospitalization, 15% of patients used oral anticoagulants, 29% acetylsalicylic acid, and 4% clopidogrel. The NIHSS score (National Institute of Health Stroke Scale – a scale for assessing neurological deficit in stroke patients) showed an average value of 10 (6–16) upon admission.

The primary parameter monitored was the time from iCMP to the initiation of dabigatran. Secondary parameters included the reasons for delaying dabigatran therapy initiation and the occurrence of clinically significant events (death, stroke, pulmonary or systemic embolism, myocardial infarction, intracerebral or major extracranial bleeding as defined by the International Society on Thrombosis and Haemostasis) within 3 months after the first incident.

Results

For the majority of patients (82%), dabigatran therapy was initiated within 14 days of iCMP onset, on average 8 days (4–12). Patients who started dabigatran therapy earlier generally had less severe iCMP: severity ranged from an average NIHSS score of 8 (6–13) when starting within 7 days to a score of 15 (9–19) for those starting dabigatran between 28 days and 3 months post-iCMP.

The most common reasons for delaying dabigatran initiation mentioned by physicians were stroke severity (22.8%), ischemic lesion size (19.4%), and hemorrhagic transformation of ischemia (14.9%).

Higher NIHSS scores at admission and higher mRS scores (modified Rankin Scale, used to assess a patient's functional independence – higher value indicates lower self-sufficiency) before the stroke were generally associated with delayed dabigatran therapy. Other independent factors included older age, higher diastolic blood pressure at admission, higher CHA₂DS₂-VASc scores, and a history of bleeding/predisposition to bleeding.

A clinically significant event within 3 months of the first iCMP was reported in 20 of 926 patients (2.2%). This included 13 embolic/ischemic and 7 hemorrhagic events.

A total of 697 (68.5%) of the 1018 patients were functionally independent (mRS score 0–2) after 3 months. During the follow-up, 31 patients (3%) died.

Conclusion and Discussion

Dabigatran therapy as secondary stroke prevention in patients with non-valvular atrial fibrillation is generally initiated early in clinical practice. This approach appears safe for patients treated with intravenous thrombolysis and/or endovascular thrombectomy. Ischemic and hemorrhagic complications are rare during the first 3 months after therapy initiation.

Currently, there are 4 major randomized controlled trials evaluating the benefits of early NOACs initiation in patients with iCMP associated with atrial fibrillation. However, we must rely on the results of observational studies for now.

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Source: Escuredo-Martinez I., Mazya M., Teutsch C. et al. Dabigatran initiation in patients with non-valvular AF and first acute ischaemic stroke: a retrospective observational study from the SITS registry. BMJ Open 2020 May 19; 10 (5): e037234, doi: 10.1136/bmjopen-2020-037234.