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Surgical LAA Occlusion and Stroke and Mortality in Cardiac Surgery Patients
Study Questions:
Is left atrial appendage surgical occlusion (LAAO) during cardiac surgery associated with a decreased risk of stroke or death, and is LAAO associated with an increased risk of developing atrial fibrillation (AF)?
Methods:
The authors used a large administrative database that includes data from both private insurance and Medicare Advantage to identify adults who had their first coronary artery bypass grafting (CABG) or open valve surgery between January 2009 and March 2017. Covariates were defined by diagnosis codes, procedure codes, or prescription claims. Discharge status and the Social Security Death Master File were used to identify patient deaths. AF was identified by AF-related health care utilization. Patients were followed until death or a change of insurance. Propensity score matching, based on more than 70 covariates, was used to compare patients with and without LAAO.
Results:
There were 75,782 patients in the database who had cardiac surgery and were included in the analyses. The average age was 66, 29% were women, 34% had pre-existing AF, and close to 6% underwent concurrent LAAO. Patients who had LAAO were more likely to have a history of AF, valve surgery (rather than CABG), and use oral anticoagulants prior to surgery.
There were 8,590 patients included in the propensity matched cohort and their baseline sociodemographic, medical, and procedure characteristics were similar. LAAO was associated with a reduced risk of stroke (hazard ratio [HR], 0.73; 95% confidence interval [CI], 0.56-0.96) and mortality (HR, 0.71; 95% CI, 0.60-0.84), but a higher risk of developing AF (rate ratio for outpatient visits, 1.17; 95% CI, 1.10-1.24; rate ratio for AF-related hospitalization, 1.13; 95% CI, 1.05-1.21). In patients with prior AF who underwent LAAO, the stroke and mortality findings were similar to the larger cohort. In the subgroup of patients without a history of AF, LAAO was not associated with a decreased risk of stroke (HR, 0.95; 95% CI, 0.54-1.68) or reduced mortality (HR, 0.92; 95% CI, 0.61-1.37); however, there was no significant interaction between AF and LAAO, suggesting that the larger cohort findings also apply to patients with AF. The findings from multiple sensitivity analyses did not alter the primary results.
Conclusions:
LAAO during cardiac surgery may be associated with a reduced risk of stroke or death and an increased risk of AF.
Perspective:
LAAO during cardiac surgery is sometimes performed in an attempt to reduce the risk of future stroke; however, there are limited data to guide this decision. The authors have shown that LAAO during cardiac surgery is associated with a reduced risk of stroke or death in patients with and without a history of AF. Since stroke is a leading cause of disability, interventions that can decrease its impact are beneficial. This work also confirmed a prior study, suggesting that in patients without a history of AF, LAAO increases the risk of AF; an effect that may limit its use in this patient population.
This study likely generalizes to many cardiac surgery patients across the US, though the use of administrative data limits analyses to information contained in codes and claims and raises the possibility of misclassification bias. While these results are intriguing, randomized trials will be needed to more definitively determine the role of LAAO in cardiac surgery patients.
Keywords: Anticoagulants, Arrhythmias, Cardiac, Atrial Appendage, Cardiac Surgical Procedures, Coronary Artery Bypass, Coronary Occlusion, Mortality, Outpatients, Primary Prevention, Stroke, Vascular Diseases
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