Association Between Left Atrial Appendage Occlusion and Readmission for Thromboembolism Among Patients With Atrial Fibrillation Undergoing Concomitant Cardiac Surgery

Abstract

Importance: The left atrial appendage is a key site of thrombus formation in atrial fibrillation (AF) and can be occluded or removed at the time of cardiac surgery. There is limited evidence regarding the effectiveness of surgical left atrial appendage occlusion (S-LAAO) for reducing the risk of thromboembolism.

Objective: To evaluate the association of S-LAAO vs no receipt of S-LAAO with the risk of thromboembolism among older patients undergoing cardiac surgery.

Design, setting, and participants: Retrospective cohort study of a nationally representative Medicare-linked cohort from the Society of Thoracic Surgeons Adult Cardiac Surgery Database (2011-2012). Patients aged 65 years and older with AF undergoing cardiac surgery (coronary artery bypass grafting [CABG], mitral valve surgery with or without CABG, or aortic valve surgery with or without CABG) with and without concomitant S-LAAO were followed up until December 31, 2014.

Exposures: S-LAAO vs no S-LAAO.

Main outcomes and measures: The primary outcome was readmission for thromboembolism (stroke, transient ischemic attack, or systemic embolism) at up to 3 years of follow-up, as defined by Medicare claims data. Secondary end points included hemorrhagic stroke, all-cause mortality, and a composite end point (thromboembolism, hemorrhagic stroke, or all-cause mortality).

Results: Among 10 524 patients undergoing surgery (median age, 76 years; 39% female; median CHA2DS2-VASc score, 4), 3892 (37%) underwent S-LAAO. Overall, at a mean follow-up of 2.6 years, thromboembolism occurred in 5.4%, hemorrhagic stroke in 0.9%, all-cause mortality in 21.5%, and the composite end point in 25.7%. S-LAAO, compared with no S-LAAO, was associated with lower unadjusted rates of thromboembolism (4.2% vs 6.2%), all-cause mortality (17.3% vs 23.9%), and the composite end point (20.5% vs 28.7%) but no significant difference in rates of hemorrhagic stroke (0.9% vs 0.9%). After inverse probability-weighted adjustment, S-LAAO was associated with a significantly lower rate of thromboembolism (subdistribution hazard ratio [HR], 0.67; 95% CI, 0.56-0.81; P < .001), all-cause mortality (HR, 0.88; 95% CI, 0.79-0.97; P = .001), and the composite end point (HR, 0.83; 95% CI, 0.76-0.91; P < .001) but not hemorrhagic stroke (subdistribution HR, 0.84; 95% CI, 0.53-1.32; P = .44). S-LAAO, compared with no S-LAAO, was associated with a lower risk of thromboembolism among patients discharged without anticoagulation (unadjusted rate, 4.2% vs 6.0%; adjusted subdistribution HR, 0.26; 95% CI, 0.17-0.40; P < .001), but not among patients discharged with anticoagulation (unadjusted rate, 4.1% vs 6.3%; adjusted subdistribution HR, 0.88; 95% CI, 0.56-1.39; P = .59).

Conclusions and relevance: Among older patients with AF undergoing concomitant cardiac surgery, S-LAAO, compared with no S-LAAO, was associated with a lower risk of readmission for thromboembolism over 3 years. These findings support the use of S-LAAO, but randomized trials are necessary to provide definitive evidence.

Conflict of interest statement

Conflict of Interest Disclosures: All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Friedman reported receiving grants from Boston Scientific, Abbott, and the National Cardiovascular Data Registry and he is funded by T32 training grant HL069749-13 from the National Institutes of Health. Dr Piccini reported receiving grants from ARCA Biopharma, Boston Scientific, Gilead Sciences, Janssen Pharmaceuticals, and Abbott to Duke for conduct of clinical trials; consultancies for Allergan, Janssen Pharmaceuticals, Bayer, Sanofi, Spectranetics, and Medtronic; and grants/grants pending from Johnson & Johnson, Boston Scientific, Gilead, St Jude Medical, and Spectranetics. Ms Wang reported receiving grants from the Food and Drug Administration, Innovation in Regulatory Science Award from Burroughs Welcome Fund, and a T32 training grant from the National Institutes of Health. Dr Holmes and the Mayo Clinic reported a financial interest in technology related to this research; that technology has been licensed to Boston Scientific. Dr Suri reported receiving funding for the Sorin Perceval Trial and the Publications Committee Partner Trial. Dr Peterson reported running the analysis center for the ACC STS Adult Cardiac Surgery Database and receiving a research grant from Janssen Pharmaceuticals and Eli Lilly. Dr Peterson is also a consultant for Janssen Pharmaceuticals and Boehringer Ingelheim. Dr Brennan holds an Innovation in Regulatory Science Award from Burroughs Welcome Fund (1014158) and a Food and Drug Administration grant (1U01FD004591-01). No other disclosures were reported.

Figures

Figure.. Unadjusted Rates of Readmission for Thromboembolism, All-Cause Mortality, Hemorrhagic Stroke, and the Composite End Point

Unadjusted rates of readmission for thromboembolism (A), all-cause mortality (B), hemorrhagic stroke (C), and the composite end point (D) among those with (orange) and without (blue) surgical left atrial appendage occlusion (S-LAAO). The reported P values were obtained from unadjusted Fine-Gray (A and C) or Cox proportional hazards models (B and D). The shaded regions indicate 95% CIs.