Clinical Pearls & Morning Reports
Whitlock et al. conducted a randomized trial that evaluated the efficacy and safety of concomitant left atrial appendage occlusion in participants with a history of atrial fibrillation undergoing cardiac surgery for another indication. Specifically, they aimed to determine whether concomitant occlusion would prevent ischemic stroke or systemic embolism in participants who continued to receive usual care, including anticoagulation. Read the NEJM Original Article here.
Q: What are some of the limitations of oral anticoagulation in patients with atrial fibrillation?
A: Atrial fibrillation is common in elderly patients and is responsible for approximately a quarter of ischemic strokes, many of which are cardioembolic and originate from the left atrial appendage. Oral anticoagulation is limited by nonadherence to prescribed medications, drug discontinuation, underdosing, and, for patients treated with vitamin K antagonists, poor control of the international normalized ratio. Left atrial appendage occlusion is hypothesized to reduce the risk of stroke among patients with atrial fibrillation, but this has not been proved in a randomized trial.
Q: Are there any potential harms associated with left atrial appendage closure?
A: The left atrial appendage is a source of atrial natriuretic peptide, and it has been hypothesized that removal of the appendage might impair renal clearance of salt and water, thereby increasing the risk of heart failure. A recent nonrandomized study supported this hypothesis.
A: The primary outcome was the first occurrence of ischemic stroke (including transient ischemic attack with positive neuroimaging) or noncerebral systemic embolism during follow-up. Ischemic stroke or systemic embolism occurred in 114 participants (4.8%) in the occlusion group and in 168 (7.0%) in the no-occlusion group (hazard ratio, 0.67; 95% confidence interval [CI], 0.53 to 0.85; P=0.001). During the first 30 days after surgery, a primary-outcome event occurred in 53 participants (2.2%) in the occlusion group and in 65 (2.7%) in the no-occlusion group (hazard ratio, 0.82; 95% CI, 0.57 to 1.18). After 30 days, a primary-outcome event occurred in 61 participants (2.7%) in the occlusion group and in 103 (4.6%) in the no-occlusion group (hazard ratio, 0.58; 95% CI, 0.42 to 0.80). The authors did not observe an increase in hospitalization for heart failure, either early after surgery or during long-term follow-up. The incidence of major bleeding or myocardial infarction was similar in the trial groups. Reexploration for bleeding within the first 48 hours after surgery occurred in 94 participants (4.0%) in the occlusion group and in 95 (4.0%) in the no-occlusion group. The 30-day mortality was 3.7% in the occlusion group and 4.0% in the no-occlusion group.
A: In the trial by Whitlock et al., surgical occlusion of the left atrial appendage provided additional protection against stroke when added to anticoagulation. Endovascular occlusion devices may also be effective as a complement to anticoagulation rather than as a replacement, but this would require testing. There are notable differences between surgical occlusion of the left atrial appendage and occlusion performed with a percutaneous endovascular device. Surgical occlusion is an extravascular procedure, whereas occlusion with an endovascular device may increase the risk of thrombus formation and embolism.