Influence of severe anemia on procedural safety and one-year outcome after left atrial appendage closure: Insights from a very high-risk cohort

Introduction: Patients undergoing left atrial appendage closure (LAAC) are often severly anemic and close to the transfusion threshold. The aim was to investigate the prevalence of severe anemia in this cohort and if procedural safety is compromised compared with non-anemic patients.

Methods and results: Comparison of severly anemic patients (Hb < 80 g/l) vs. non-severly anemic patients in the prospective, multicentre observational LAARGE registry of patients undergoing LAAC. A total of 638 patients (anemia 22.3% vs non-anemic 77.7%) were included. Anemic patients were older (77.1 years ± 7.9 vs 75.6 years ± 7.9, p = 0.014), had more comorbidities, higher CHA2DS2-VASc (4.8 vs 4.4, p = 0.017) and higher HAS-BLED (4.3 vs 3.8, p < 0.001) scores. Implant success was not influenced by anemia (99.3% vs 97.2%). Severe in-hospital (0.7% vs 5.6%, p = 0.01) and overall complications (8.5% vs 13.7%, p = 0.11) were less common in patients with anemia, driven by fewer pericardial effusions. Mortality was higher in anemic patients and associated with an increased hazard ratio, albeit not significantly (16.0% vs 10.3%, HR 1.61 (95%-CI: 0.97-2.67), p = 0.06). In the one-year follow-up, composite outcome of death, stroke or systemic embolism occurred in 22/142 anemic and in 54/496 non-anemic patients with an adjusted HR of 1.04 (95%-CI 0.62-1.73, p = 0.89).

Conclusion: Severe anemia close to the transfusion threshold is common in patients undergoing LAAC. However, this does not influence in-hospital complications or implant success. One-year mortality is higher in anemic patients, mainly driven by co-morbidities.