Left Atrial Appendage Occlusion Study II (LAAOS II)

Area of Science:

• Cardiology
• Vascular Surgery
• Clinical Trials

Background:

• Atrial fibrillation (AF) poses a stroke risk, for which anticoagulation is standard. Left atrial appendage (LAA) occlusion is an alternative therapy.
• Evidence for the safety and efficacy of LAA occlusion is limited.
• The Left Atrial Appendage Occlusion Study II (LAAOS II) aimed to assess the feasibility of a large-scale trial for stroke prevention in AF patients.

Purpose of the Study:

• To determine the prevalence of AF and stroke risk factors in patients undergoing cardiac surgery.
• To evaluate the feasibility, recruitment rate, and safety of LAA occlusion compared to anticoagulation in AF patients with increased stroke risk.

Main Methods:

• A cross-sectional study of 1889 cardiac surgery patients identified AF prevalence.
• 51 AF patients with high stroke risk were randomized to LAA occlusion (n=26) or oral anticoagulation (n=25).
• Safety outcomes, recruitment rates, and composite clinical events were assessed at 1 year.

Main Results:

• AF prevalence was 10.8% (204/1889), with 5.2% (98/1889) meeting trial eligibility criteria.
• Recruitment occurred at 1.6 patients/center/month; no significant bleeding at the LAA site was observed post-occlusion.
• At 1 year, the composite endpoint (death, MI, stroke, emboli, major bleeding) occurred in 15.4% of the occlusion group and 20.0% of the anticoagulation group (RR 0.71, P=0.61). Stroke occurred in 1 patient (occlusion) and 3 patients (anticoagulation).

Conclusions:

• LAA occlusion is a safe procedure when performed during cardiac surgery.
• A large clinical trial to confirm LAA occlusion's efficacy in preventing stroke in cardiac surgery patients is feasible with design modifications.