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Atrial fibrillation after noncardiac surgery tied to higher stroke risk

Reuters Health - 01/09/2020 - Patients who develop atrial fibrillation following noncardiac surgery have a significantly increased risk of suffering transient ischemic attack (TIA) or stroke over the next five years, a retrospective cohort study shows.

AF that develops following noncardiac surgery is thought to be triggered by postoperative stress and systemic inflammation, coupled with predisposing comorbid conditions. What's not clear is how often the arrhythmia is an isolated postoperative event or an arrhythmia that is likely to persist.

To investigate, Dr. Alanna Chamberlain and colleagues at Mayo Clinic, in Rochester, Minnesota, took a look back at 452 patients with new-onset AF within 30 days after noncardiac surgery between 2000 and 2013. They were matched 1:1 on age, sex, year of surgery and type of surgery to patients who had noncardiac surgery but did not develop postoperative AF. In both groups, the median age was 75 years and 52% were men.

Patients with postoperative AF had significantly higher CHA2DS2-VASc scores compared with the no AF group (median, 4 vs. 3). During a median follow-up of 5.4 years, 71 ischemic strokes/TIAs, 266 subsequent documented AF episodes (defined as AF >30 days after the surgery) and 571 deaths (172 heart-related) occurred.

After accounting for age and Charlson Comorbidity Index, patients with postoperative AF had a greater than two-fold higher risk of suffering stroke or TIA during follow-up (hazard ratio, 2.69; 95% confidence interval, 1.35 to 5.37). The absolute risk difference at five years was 4.7%.

Postoperative AF patients also had a statistically significantly higher risk of having AF documented more than 30 days after the surgery (HR, 7.94; 95% CI, 4.85 to 12.98) and dying from any cause (HR, 1.66; 95% CI, 1.32 to 2.09). The absolute risk differences at five years were 39.3% and 9.4%, respectively.

There was no significant difference in the risk of cardiovascular death in either group.

In their JAMA report, the researchers say these findings "might have rhythm monitoring and treatment implications and suggest that, for many patients, AF after noncardiac surgery is not a transient arrhythmia simply dependent on resolution of the postoperative state. Rather, the postoperative state may be considered a 'stress test' for the manifestation of AF."

They caution, however, that "the implications of these findings for the management of postoperative AF, such as the need for anticoagulation therapy, require investigation in randomized trials."

By Megan Brooks

SOURCE: https://bit.ly/3hSDIgy JAMA, published online September 1, 2020.

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