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Adding prophylactic left atrial appendage (LAA) closure to planned cardiac surgery was linked to lower stroke risk for patients without atrial fibrillation (Afib, or AF), based on a meta-analysis.

Pooling six observational and randomized studies turned up significantly decreased risk of cerebrovascular accidents (CVA) with LAA occlusion (LAAO) compared with controls (log-rank P=0.02), reported a group led by Massimo Baudo, MD, of Lankenau Institute for Medical Research in Wynnewood, Pennsylvania. The CVA rates were consistently lower for the LAAO-treated patients over time:

• At 1 year, 1.4% vs 2.4%
• At 3 years, 2.6% vs 4.7%
• At 5 years, 4.3% vs 6.8%

Although these lower CVA rates did not translate into a significant difference in survival out to 8 years (HR 0.80, 95% CI 0.63-1.02), there was an early survival benefit with LAAO in a 4-year landmark analysis (89.6% vs 86% P=0.04), they reported in .

Whether LAA closure is really effective for stroke prevention in people without Afib will need to be proven in randomized trials. Baudo and colleagues cited the ongoing , LAA-CLOSURE, and LAACS-2 trials as ones that might provide more definite answers in the future.

LAA closure is thought to minimize blood stasis in the LAA that can generate cardioembolic thrombi and contribute to the development of Afib-related stroke.

"Besides demonstrating efficacy in preventing CVA, safety must also be established," the authors wrote. "The LAA is calculated to contribute to up to 10% of the total atrial volume and is neurohormonally active in sinus rhythm and variable hormonal changes have been documented across different techniques of LAAO. The effect on cardiac function and fluid homeostasis of excluding this structure in such patients must be established."

Concomitant LAAO had been proven beneficial for reducing the risk of thromboembolism for Afib patients with a CHA₂DS₂-VASc score ≥2 at the time of cardiac surgery in the LAAOS-III randomized trial. The strategy now has a strong recommendation in guidelines for these higher stroke risk patients.

Evidence for LAA closure in the absence of Afib is more limited, with only two randomized trials -- the modest-sized and trials -- available for inclusion in the present meta-analysis. More than 80% of patients in the meta-analysis came from three propensity-matched studies and one study using inverse probability treatment weighting.

"The 37% relative risk reduction in stroke rate, if genuine and replicable, would be both statistically and clinically significant. However, their findings should be interpreted with caution, and should not, in isolation, be used to recommend widespread adoption of surgical LAAO in patients without AF undergoing cardiac surgery," commented Gregory Lip, MD, and colleagues at the University of Liverpool, England, in an ,

The large LeAAPS study is not expected to report results until 2032. Until then, the editorialists urged that clinicians make the decision to perform LAAO in this setting on a case-by-case basis.

"Surgical LAAO may be justifiable in those meeting the strict inclusion and exclusion criteria of [ATLAS and LAACS] although these studies are by no means conclusive due to their small sample sizes. In those not meeting these criteria, enrollment into one of the aforementioned [randomized controlled trials], if eligible and accessible, is preferable," Lip and colleagues wrote.

For their meta-analysis, Baudo and colleagues included six studies published from 2018 to 2023 that reported on patients with normal sinus rhythm who underwent cardiac surgery, with and without concomitant LAAO.

Among these study participants, 2,146 got LAAO and 1,984 did not. Various LAAO techniques were employed, including direct suture, clipping, and cut and sew.

Across study cohorts, the mean age ranged from around 60 to 70; all had a majority of men. The two studies that reported CHA₂DS₂-VASc showed averages of 3.1 and 3.4. Baudo's group acknowledged the lack of sufficient CHA₂DS₂-VASc data that would have been helpful in determining if the benefit of LAAO is wide-spanning or limited to a high-risk subgroup.

Based on just three studies with the available information, the authors said they were unable to detect a difference in the incidence of postoperative Afib between groups (RR 1.050, 95% CI 0.863-1.277).

Definitions of CVA varied across the studies, with half not specifying at all how it was defined. One included both ischemic and hemorrhagic stroke as well as transient ischemic attack (TIA), another excluded hemorrhagic stroke but was unclear about TIAs, and a third used administrative codes largely for ischemic stroke but left some room for ambiguity.

Finally, the study was also limited by the lack of data on perioperative and long-term antithrombotic therapy, Lip's group observed.

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