Perioperative atrial fibrillation and the long-term risk of ischemic stroke

Area of Science:

• Cardiology
• Neurology
• Health Services Research

Background:

• Clinically apparent atrial fibrillation is a known risk factor for ischemic stroke.
• The long-term stroke risk associated with perioperative atrial fibrillation, often considered a transient response to surgical stress, remains unclear.

Purpose of the Study:

• To investigate the association between newly diagnosed perioperative atrial fibrillation and the long-term risk of ischemic stroke.
• To compare this risk between patients undergoing cardiac versus noncardiac surgery.

Main Methods:

• Retrospective cohort study utilizing administrative claims data from California hospitals (2007-2011).
• Included patients hospitalized for surgery, discharged alive, and without prior cerebrovascular disease or atrial fibrillation.
• Identified new-onset perioperative atrial fibrillation using validated codes and tracked ischemic strokes post-discharge.

Main Results:

• Over 1.7 million patients were analyzed; 1.43% developed new-onset perioperative atrial fibrillation.
• At 1 year post-discharge, stroke rates were 0.99% with perioperative atrial fibrillation vs. 0.83% without after cardiac surgery.
• At 1 year post-discharge, stroke rates were 1.47% with perioperative atrial fibrillation vs. 0.36% without after noncardiac surgery.
• Perioperative atrial fibrillation was associated with increased stroke risk after both cardiac (HR, 1.3) and noncardiac surgery (HR, 2.0), with a stronger association after noncardiac surgery.

Conclusions:

• New-onset perioperative atrial fibrillation is linked to an elevated long-term risk of ischemic stroke.
• The risk of stroke following perioperative atrial fibrillation is substantially higher after noncardiac surgery compared to cardiac surgery.