Poster Presentation Australian and New Zealand Stroke Organisation Conference 2026

Left atrial appendage contrast retention is associated with breakthrough stroke (#116)

Mikito Saito 1 2 , Hiroyuki Kawano 2 , Shota Watanabe 3 , Takuya Adachi 3 , Risa Toyota 2 , Reona Miwa 2 , HAYATE ONUKI 2 , Ayane Kawatake 2 , Atsuhi Yamamichi 2 , Kaoru Nakanishi 2 , Eisaku Tsuji 4 , Shinya Tomari 2 , Yuko Honda 2 , Miho Gomyo 5 , Yoshiko Unno 2 , Teruyuki Hirano 2
  1. University of Newcastle, Mount Hutton, NSW, Australia
  2. Department of Stroke and Cerebrovascular Medicine, Kyorin University, Mitaka, Tokyo, Japan
  3. Department of Radiology, Kyorin University Hospital, Mitaka, Tokyo, Japan
  4. Department of Neurosurgery, Takaisifujii Hospital, Takaishi, Osaka, Japan
  5. Department of Radiology, Kyorin University, Mitaka, Tokyo, Japan

Background:

Oral anticoagulation (OAC) reduces ischaemic stroke risk in patients with atrial fibrillation (AF). However, ischaemic stroke despite anticoagulation, so-called breakthrough stroke, still occurs. We investigated whether left atrial appendage (LAA) contrast retention on cardiac CT obtained immediately after brain CT perfusion (CTP), reflecting delayed washout of contrast used for CTP, was associated with breakthrough stroke.

Methods:
We retrospectively analyzed patients with AF-related cardioembolic stroke who underwent acute brain CTP and cardiac CT simultaneously. Breakthrough stroke was defined as cardioembolic stroke in patients taking OAC before stroke onset. LAA contrast retention was assessed on cardiac CT obtained immediately after brain CTP using the same contrast injection, based on visual and quantitative assessment. Multivariable logistic regression was adjusted for age, persistent AF, and prior stroke. Sensitivity analyses were performed by replacing persistent AF with LAVI and by applying a stricter breakthrough stroke definition excluding inappropriate dosing or poor adherence.

Results:
Among 247 patients, 99 (40.1%) had breakthrough stroke and 63 (25.5%) met the stricter definition. LAA contrast retention occurred more frequently in breakthrough stroke than non-breakthrough stroke (20.4% vs 8.2%, p=0.01). Multivariable analysis revealed that LAA contrast retention was independently associated with breakthrough stroke (adjusted OR 2.78, 95% CI 1.21–6.57, p=0.02). This association remained significant in sensitivity analysis using LAVI (adjusted OR 2.50, 95% CI 1.07–6.01, p=0.03) and the stricter breakthrough definition (adjusted OR 2.81, 95% CI 1.23–6.40, p=0.01).

Conclusions:

Among patients with acute stroke, LAA contrast retention on cardiac CT was independently associated with breakthrough stroke.