Yao X, et al. - Researchers aimed at assessing the association of surgical occlusion of the left atrial appendage (LAAO) performed during cardiac surgery with risk of stroke, mortality, and development of subsequent atrial fibrillation (AF). Compared with no surgical LAAO, concurrent surgical LAAO was noted to be associated with reduced risk of subsequent stroke and all-cause mortality among patients undergoing cardiac surgery.

Methods

• Researchers performed a retrospective cohort study using a large US administrative database that contains data from adult patients (≥18 years) with private insurance or Medicare Advantage who underwent coronary artery bypass graft (CABG) or valve surgery between January 1, 2009, and March 30, 2017, with final follow-up on March 31, 2017.
• They used one-to-one propensity score matching to balance patients on 76 dimensions to compare those with vs without LAAO, stratified by history of prior AF at the time of surgery.
• Stroke (ie, ischemic stroke or systemic embolism) and all-cause mortality were assessed as the primary outcomes.
• Postoperative AF (AF within 30 days after surgery among patients without prior AF) and long-term AF-related health utilization (event rates of outpatient visits and hospitalizations) were assessed as the secondary outcomes.

Results

• Cardiac surgery was performed on 75,782 patients (mean age, 66.0 [SD, 11.2] years; 22,091 [29.2%] women, 25,721 [33.9%] with preexisting AF); 4374/75,782 (5.8%) underwent concurrent LAAO, and mean follow-up of 2.1 (SD, 1.9) years was performed.
• LAAO was associated with a reduced risk of stroke (1.14 vs 1.59 events per 100 person-years; hazard ratio [HR], 0.73 [95% CI, 0.56-0.96]; P=.03) and mortality (3.01 vs 4.30 events per 100 person-years; HR, 0.71 [95% CI, 0.60-0.84]; P < .001) among the 8,590 propensity score–matched patients, .
• Findings suggested a correlation of LAAO with higher rates of AF-related outpatient visits (11.96 vs 10.26 events per person-year; absolute difference, 1.70 [95% CI, 1.60-1.80] events per person-year; rate ratio, 1.17 [95% CI, 1.10-1.24]; P < .001) and hospitalizations (0.36 vs 0.32 event per person-year; absolute difference, 0.04 [95% CI, 0.02-0.06] event per person-year; rate ratio, 1.13 [95% CI, 1.05-1.21]; P=.002).
• Patients with prior AF (6438/8590 [74.9%]) and also with LAAO, compared to those without LAAO, demonstrated risk of stroke of 1.11 vs 1.71 events per 100 person-years (HR, 0.68 [95% CI, 0.50-0.92]; P=.01) and risk of mortality of 3.22 vs 4.93 events per 100 person-years (HR, 0.67 [95% CI, 0.56-0.80]; P < .001), respectively.
• Patients without prior AF (2152/8590 [25.1%]) and had underwent LAAO, compared to those who did not undergo LAAO, demonstrated risk of stroke of 1.23 vs 1.26 events per 100 person-years (HR, 0.95 [95% CI, 0.54-1.68]), risk of mortality of 2.30 vs 2.49 events per 100 person-years (HR, 0.92 [95% CI, 0.61-1.37]), and risk of postoperative AF of 27.7% vs 20.2% events per 100 person-years (HR, 1.46 [95% CI, 1.22-1.73]; P < .001).
• No significant interaction between prior AF and LAAO was noted (P=.29 for stroke and P=.16 for mortality).