Late Stroke After Coronary Artery Bypass Grafting

Abstract

The use of oral anticoagulation therapy to prevent stroke in patients with atrial fibrillation (AF) is one of the most successful therapies in cardiovascular and stroke medicine. 1 The introduction of direct oral anticoagulants has increased the ease and safety of delivering this therapy 1 ; thus, there is a strong motivation to deliver this therapy to patients at risk of AFrelated stroke. More than 2 million cardiac surgeries are performed each year, and 20% to 30% of these patients develop postoperative AF. 2 Although most of these patients have traditional AF and stroke risk factors, 2 it is postulated that much of this AF may be transient, the result of both local inflammation and a systemic inflammatory response. 3 Clinicians speculate that AF may be self-limited in patients following cardiac surgery similar to other situations of transient stress, such as medical illness and noncardiac surgery, 4 and thus longterm treatment with oral anticoagulation therapy may not be necessary.Previous studies 5,6 using administrative data have attempted to determine the long-term risk of stroke in patients with AF following cardiac surgery. In nearly 109 000 patients who underwent cardiac surgery between 1996 and 2006 in Ontario, Canada, 5 1.8% experienced a stroke perioperatively and 3.6% experienced a stroke in the ensuing 2 years. Atrial fibrillation was present preoperatively in 9574 patients (8.8%), and new postoperative AF developed in 18 046 (18.2%). After multivariable adjustment, postoperative AF was significantly associated with an increased risk of perioperative stroke (hazard ratio [HR], 1.5; 95% CI, 1.3-1.6) but not stroke following hospital discharge (HR, 1.1; 95% CI, 1.0-1.2). 5 In 2014, Gialdini et al 6 used administrative data from California to study patients after both cardiac and noncardiac surgery, nearly 25 000 of whom developed postoperative AF and nearly 14 000 of whom experienced a stroke. After multivariable adjustment, postoperative AF was associated with an increased risk of developing stroke following cardiac surgery (HR, 1.3; 95% CI, 1.1-1.6) and after noncardiac surgery (HR, 2.0; 95% CI, 1.7-2.3; P < .001). 6 Together, these 2 large cohort studies suggest that AF following cardiac surgery is associated with a more modest risk of later stroke than is seen early after surgery and compared with other types of surgery, raising the possibility that long-term oral anticoagulation therapy may not always be necessary in this setting.In this issue of JAMA Cardiology, Butt et al 7 used the Danish National Patient Registry to identify 2108 patients with AF