{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,9]],"date-time":"2026-06-09T23:57:41Z","timestamp":1781049461421,"version":"3.54.1"},"reference-count":0,"publisher":"Pasifika Medical Association Group","issue":"1636","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["NZMJ"],"abstract":"<jats:p>aims: The aim of this article was to characterise the mechanisms underlying \u201cbreakthrough\u201d ischaemic stroke (IS) or transient\nischaemic attack (TIA) despite oral anticoagulation in patients with atrial fibrillation (AF).\nmethods: We conducted a cross-sectional analysis of adults with non-valvular AF who experienced IS\/TIA in the fifth Auckland\nRegional Community Stroke Study (ARCOS V: September 2020 to August 2021). Using clinical records, we collected data on demographics,\ncomorbidities and peri-event anticoagulant dosing and intake. Anticoagulant adherence in the months preceding IS\/TIA was\ncategorised as good control if proportion of days covered (PDC) \u226580% for direct oral anticoagulant users or time in therapeutic range\n(TTR) \u226570% for warfarin users. IS\/TIA mechanism was adjudicated using standardised criteria and classified as cardioembolic or\nnon-cardioembolic, and patient characteristics were compared.\nresults: Among 179 patients (76\/179 [43%] female), 138\/179 events (77%) were adjudicated as cardioembolic, while the remainder\nwere attributed to competing mechanisms. Compared with non-cardioembolic events, cardioembolic aetiology was associated with\nyounger median age (72 vs 81 years), lower proportions with good anticoagulant control (87\/138 [63%] vs 34\/41 [83%], p=0.017) and\nhigher rates of peri-event missed or under-dosing (90\/138 [65%] vs 18\/41 [44%], p=0.014). In multivariable analysis, good control was\nindependently associated with higher odds of a non-cardioembolic mechanism (adjusted odds ratio 3.67 [95% confidence interval\n1.35\u20139.99], p=0.011).\nconclusion: Most breakthrough IS\/TIA events on oral anticoagulation were either associated with anticoagulant under-exposure (in\npatients with a cardioembolic aetiology) or a competing mechanism rather than anticoagulant failure. These findings highlight the\nimportance of careful assessment to inform appropriate secondary prevention strategies.<\/jats:p>","DOI":"10.26635\/6965.7380","type":"journal-article","created":{"date-parts":[[2026,6,9]],"date-time":"2026-06-09T23:05:51Z","timestamp":1781046351000},"page":"44-51","source":"Crossref","is-referenced-by-count":0,"title":["Mechanisms of ischaemic strokes and transient ischaemic attacks despite oral anticoagulation in patients with atrial fibrillation"],"prefix":"10.26635","volume":"139","author":[{"given":"Karim","family":"Mahawish","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Valery","family":"Feigin","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rita","family":"Krishnamurthi","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Harvey","family":"White","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"11177","published-online":{"date-parts":[[2026,6,12]]},"container-title":["New Zealand Medical Journal"],"original-title":[],"deposited":{"date-parts":[[2026,6,9]],"date-time":"2026-06-09T23:05:52Z","timestamp":1781046352000},"score":1,"resource":{"primary":{"URL":"https:\/\/nzmj.org.nz\/journal\/vol-139-no-1636\/mechanisms-of-ischaemic-strokes-and-transient-ischaemic-attacks-despite-oral-anticoagulation-in-patients-with-atrial-fibrillatio"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,6,12]]},"references-count":0,"journal-issue":{"issue":"1636","published-online":{"date-parts":[[2026,6,12]]}},"URL":"https:\/\/doi.org\/10.26635\/6965.7380","relation":{},"ISSN":["1175-8716"],"issn-type":[{"value":"1175-8716","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,6,12]]}}}