Risks and benefits of procedure versus medication in afib vary by individual

Left atrial appendage occlusion (LAAO) is effective for stroke prevention in atrial fibrillation in patients at high bleeding risk but less effective when stroke risk is high, according to a recent study.

Researchers performed a decision analysis using Markov modeling to determine the optimal strategy for stroke prevention in patients with atrial fibrillation based on individual risks for ischemic stroke and bleeding. The target population was 70-year-old patients with nonvalvular atrial fibrillation and without previous stroke. LAAO was compared with warfarin or direct oral anticoagulants (DOACs), and the primary end point was clinical benefit measured in quality-adjusted life-years. The results were published Aug. 16 by Annals of Internal Medicine.

In the base-case analysis, the baseline risks for stroke and bleeding determined whether LAAO was preferred over anticoagulants in the target population. The combined risks favored LAAO when bleeding risk was higher and stroke risk was lower, but the benefit of LAAO became less certain as stroke risk rose. In patients with the highest bleeding risk (a HAS-BLED score of 5), LAAO was favored in more than 80% of model simulations of CHA₂DS₂-VASc scores between 2 and 5, but the probability of LAAO benefit (>80%) in terms of quality-adjusted life-years at lower bleeding risks (a HAS-BLED score of 0 to 1) was limited to patients with lower stroke risks (a CHA₂DS₂-VASc score of 2). The net benefit of LAAO was less certain than that of DOACs because DOACs have a lower bleeding risk than warfarin, the authors noted. Results were consistent in the sensitivity analysis when the ORBIT bleeding score was used and when alternative sources of data on LAAO's clinical effectiveness were considered.

The researchers concluded that LAAO was more likely to be preferred over warfarin in patients at higher bleeding risk but lower stroke risk, that the clinical benefit of LAAO included a survival benefit versus warfarin, and that LAAO was preferred over DOACs in a smaller range of stroke and bleeding risks, since DOACs are less likely than warfarin to cause bleeding. “Our decision model may help clinicians to further understand and explain to their patients the tradeoffs between ischemic stroke and bleeding events for different treatment options,” they wrote.

An accompanying editorial advised cautious interpretation of the results, noting that the data sources for the study were previous trials and meta-analyses and that no long-term data from LAAO trials are available. The editorialist also questioned some of the model assumptions, pointing out that LAAO may not have been available for all patients with previous bleeding. The editorial cautioned against generalizing the findings to patients in whom the CHA₂DS₂-VASc and HAS-BLED scores are not valid. While the study is “innovative and insightful” and “has substantial scientific merit,” the editorialist wrote, “clinicians caring for patients with [atrial fibrillation] need further research to guide decisions when faced with the dilemma of anticoagulation versus LAAO.”