Mortality and Stroke after Routine Left Atrial Appendage Occlusion in Patients Undergoing Isolated Mitral Repair without Atrial Fibrillation in the United States.

Background: The role of prophylactic concomitant left atrial appendage closure during mitral repair in patients without atrial fibrillation (AF) is not defined.

Objectives: The objective was to compare long-term outcomes of patients who had left atrial appendage closure during mitral repair with those who did not in patients without AF.

Methods: A large national registry was used to identify 38,597 patients undergoing isolated mitral repair from 2010 to 2019. After excluding prior cardiac surgery, endocarditis, emergencies, and AF history, we identified 10,810 isolated mitral repairs. Of these, 1,875(17%) received closure and 8,935(83%) did not. Propensity score matching was performed on 27 baseline characteristics. The primary outcome of any stroke or thromboembolism was compared between matched groups using the cumulative incidence function in a Fine-Gray model with death as a competing risk. All-cause mortality was compared in a Cox-proportional hazard model.

Results: Propensity matching yielded 1,875 well-matched patient pairs (mean age:71 years, 45%female, median CHA2DS2-Vasc score 3.0). New post-operative AF was more common in the closure group (45%vs38.4%, p<0.01). There was no difference in 30-day mortality (1.2%vs1.1%, p=0.88). There was a reduction in stroke and thromboembolism over 5 years (6.4% vs 8.3%, HR: 0.74, 95%CI:0.57-0.96, p=0.023). There was no difference in 5-year survival (91% vs 91%, HR: 0.99, 95%CI:0.80-1.23, p=0.95).

Conclusions: Left atrial appendage closure at the time of isolated mitral repair in patients without AF may be associated with increased incidence of post-operative AF, but reduced late stroke and thromboembolism compared to mitral repair alone.