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Canadian Journal of Cardiology

Obstructive Sleep Apnea as a Predictor of Atrial Fibrillation After Coronary Artery Bypass Grafting

Published:November 13, 2014DOI:https://doi.org/10.1016/j.cjca.2014.11.008
      To the Editor:
      We read with great interest the report by Qaddoura et al. in the Canadian Journal of Cardiology.
      • Qaddoura A.
      • Kabali C.
      • Drew D.
      • et al.
      Obstructive sleep apnea as a predictor of atrial fibrillation after coronary artery bypass grafting: a systematic review and meta-analysis.
      This article reported the predicted value of obstructive sleep apnea (OSA) on post–coronary artery bypass graft atrial fibrillation (PCAF). We congratulate the authors for conducting this wonderful study because they concluded that OSA might be a strong predictor of PCAF through this comprehensive meta-analysis.
      Nonetheless, we would like to point out some issues that are likely to affect the accuracy of their results: (1) The authors defined PCAF as “an episode of atrial fibrillation from the end of the operation to hospital discharge”; however, a pilot study by Sharma et al.,
      • Sharma S.
      • Daggubatti R.
      • Tribble R.W.
      • Petit S.J.
      • Gross K.
      Prevalence of Obstructive Sleep Apnea in Patients Undergoing Coronary Artery Bypass Graft Surgery (CABG). A Pilot Study.
      which followed their patients for 30 days after operation, was also included in this meta-analysis. We wonder whether it is reasonable to include this study according to the authors' definition of PCAF. The authors should make the definition clearer if they intend to include Sharma et al.’s study.
      • Sharma S.
      • Daggubatti R.
      • Tribble R.W.
      • Petit S.J.
      • Gross K.
      Prevalence of Obstructive Sleep Apnea in Patients Undergoing Coronary Artery Bypass Graft Surgery (CABG). A Pilot Study.
      In the subgroup analysis, the authors indicated that only 1 study reported the association with severe OSA; to our surprise, there were 3 studies in the corresponding Forest plot. This should be explained clearly in the report. In addition, if the authors regarded an apnea-hypopnea index (AHI) > 30 to be as severe as OSA, why should Mooe et al.’s study, in which the cutoff value of AHI was 5, be included in the subanalysis?
      • Mooe T.
      • Gullsby S.
      • Rabben T.
      • Eriksson P.
      Sleep-disordered breathing: a novel predictor of atrial fibrillation after coronary artery bypass surgery.
      The definition of “severe OSA” should be described in detail.
      Overall, the report highlighted the value of OSA in predicting PCAF; further high-quality trials are warranted to confirm this result.

      Disclosures

      The authors have no conflicts of interest to disclose.

      References

        • Qaddoura A.
        • Kabali C.
        • Drew D.
        • et al.
        Obstructive sleep apnea as a predictor of atrial fibrillation after coronary artery bypass grafting: a systematic review and meta-analysis.
        Can J Cardiol. 2014; 30: 1516-1522
        • Sharma S.
        • Daggubatti R.
        • Tribble R.W.
        • Petit S.J.
        • Gross K.
        Prevalence of Obstructive Sleep Apnea in Patients Undergoing Coronary Artery Bypass Graft Surgery (CABG). A Pilot Study.
        J Sleep Disor: Treat Care. 2012; 1: 1-5
        • Mooe T.
        • Gullsby S.
        • Rabben T.
        • Eriksson P.
        Sleep-disordered breathing: a novel predictor of atrial fibrillation after coronary artery bypass surgery.
        Coron Artery Dis. 1996; 7: 475-478

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