The impact of prior antithrombotic status on cerebral infarction in patients with atrial fibrillation

Background: Anticoagulation effectively prevents cardioembolic stroke in atrial fibrillation (AF) patients, whereas it is less effective than antiplatelet therapy (AT) in noncardioembolic stroke prevention. We hypothesized that the ischemic lesion pattern and vascular patency would differ according to the antithrombotic treatment status in AF patients.

Methods: The medical records of 1078 acute ischemic stroke patients with AF were retrospectively reviewed. Patients were classified according to medication at stroke onset: (1) optimal anticoagulation (OAC; international normalized ratio [INR] 1.7-3.0; n = 36); (2) suboptimal anticoagulation (SOAC; INR ≤1.7; n = 134); (3) AT (n = 285); and (4) control (no antithrombotic medication; n = 623). Imaging and clinical variables of each group were compared with that of controls.

Results: Small cortical or single subcortical infarctions were more common in the OAC group than in controls (6% vs. 1% and 22% vs. 8%, respectively; standardized residual, 2.4 and 2.8). Multicirculatory infarctions were less common in the OAC group than in controls (0% vs. 11%; standardized residual, -2.0). Obstruction of the corresponding artery was less common in the OAC group than in controls (26.5% vs. 46.5%, P = .02). Initial neurologic severity was lower in the OAC and AT groups than in controls (P = .01 and .03, respectively). OAC and AT were independently associated with favorable functional outcome at 3-months (P = .015 and <.001, respectively).

Conclusions: Ischemic stroke can occur during OAC in AF patients. Small cortical or single subcortical lesions were more common than typical cardioembolic lesion patterns. OAC and AT were protective against severe neurologic deficit and independently associated with favorable outcome, but SOAC was not.