Atrial flutter doesn’t equal AFib in stroke risk scoring
Atrial fibrillation (AFib) and atrial flutter (AFL) are often regarded as interchangeable when informing the management of stroke risk. However, a new study in JAMA Network Open suggests clinical outcomes are worse for patients with AFib, even if they have the same values on the standard CHA2DS2-VASc scoring system.
“The current recommended level of CHA2DS2-VASc score (≥2) used to prevent ischemic stroke in patients with atrial flutter should be re-evaluated and prospectively studied,” concluded lead author Yu-Sheng Lin, MD, with Chang Gung Memorial Hospital in Taiwan, and colleagues.
Lin and coauthors studied nearly 220,000 individuals from a national database in Taiwan, matching by age and sex those with AFib, AFL and neither condition. Patients with AFib were older, more often female and had the highest CHA2DS2-VASc scores, which indicate greater stroke risk.
After stratification by CHA2DS2-VASc score, the researchers noted the following event rates per 100 person-years:
- Ischemic stroke: 3.08 for AFib patients, 1.45 for AFL and 0.97 for control individuals.
- Heart failure hospitalization: 3.39 for AFib, 1.57 for AFL and 0.32 for controls.
- All-cause mortality: 17.8 for AFib, 13.9 for AFL and 4.2 for controls.
The incidence of stroke increased in all three groups as CHA2DS2-VASc scores went up, but the researchers found the risk of stroke for AFib patients with a score of 1 was similar to that of AFL patients with a score of 2. Likewise, a score of 2 for AFib patients signaled a similar risk as a score of 4 for those with AFL.
Lin et al. noted that according to current guidelines, “patients with AFL should be treated in the same manner as patients with (AFib) for preventing ischemic stroke.” But their findings suggest that shouldn’t necessarily be the case.
“Our results indicate that patients with AFL may be prescribed anticoagulants when the CHA2DS2-VASc score is 4 or higher [with an (incidence density) of 2.3 percent] and non–vitamin K oral anticoagulants when the CHA2DS2-VASc score is 2 or higher (with an ID of 1.0 percent),” the researchers wrote.
“However, from a statistical significance point of view, the incidences of ischemic stroke in the AF cohort across all levels of CHA2DS2-VASc and in the AFL cohort at a CHA2DS2-VASc score of 5 to 9 were significantly higher than in the control cohort. Thus, oral anticoagulants should be considered for patients with AFL and patients with AF when the CHA2DS2-VASc score is 5 or higher.”
The authors said it is unknown whether their results could be extrapolated to non-Asian populations. They also noted they didn’t subclassify AFib into paroxysmal, persistent and chronic types, which might have different clinical outcomes.
Daniel joined TriMed’s Chicago editorial team in 2017 as a Cardiovascular Business writer. He previously worked as a writer for daily newspapers in North Dakota and Indiana.