Alleged LAA Closure Device Risk Factor May Not Worsen Risk

The study covered in this summary was published in researchsquare.com as a preprint and has not yet been peer reviewed.

Key Takeaways

• Incomplete device endothelialization (IDE) is common in the 6 months after a successful left atrial appendage (LAA) closure procedure, especially in patients with persistent atrial fibrillation (AF), larger LAA ostial diameter, and larger left atrial (LA) size.

• IDE is not necessarily associated with thromboembolic events or poor clinical outcomes in patients with LAA closure given appropriate antithrombotic therapy.

• IDE does not appear to be a strong predictor of device-related thrombosis (DRT).

Why This Matters

• LAA closure is a treatment for AF to reduce risk for stroke in nonvalvular AF patients with contraindications to oral anticoagulation therapy.

• It is believed, but without much trial evidence, that a poorly endothelialized LAA closure device might lead to DRT, which might raise the risk for stroke.

Study Design

• A total of 101 patients with nonvalvular AF were prospectively enrolled from February to December 2019 after undergoing percutaneous LAA closure, and clinically followed for 6 months. Patients with severe renal failure or poor cardiac CT imaging were excluded.

• Oral anticoagulation was prescribed for the first 45 days after device implication, or for 3 months in those who had same-session LAA closure and catheter ablation. Dual antiplatelet therapy with aspirin and clopidogrel was then prescribed in accordance with the current guidelines. 

• IDE was defined as LAA attenuation of more than 100 Hounsfield units (HU) on CT imaging, or an LAA-to-LA attenuation ratio of more than 0.25 HU with evidence of trans-fabric leak (contrast agent entering the LAA through the device fabric rather than around the device) 6 months after implantation. DRT was diagnosed on detection of filling defects on the atrial aspect of the LAA closure device.

• Patients with and without IDE were compared for the composite endpoint of major adverse cerebral or cardiac events (MACCE), which included death from any cause, heart failure hospitalization, acute ischemic stroke, transient ischemic attack, peripheral vascular embolism, and major bleeding.

Key Results

• Among 101 patients, IDE was detected in 64.4% of the patients; the remaining 35.6% showed complete device endothelialization (CDE).  

• Patients with IDE had larger LAA ostial diameter and larger LA size, but the two groups did not differ significantly in baseline clinical features, other echocardiographic features, or LAA closure procedural characteristics.

• IDE was independently associated with persistent AF, increased LAA ostial diameter, and greater LA size in multivariate analysis.

• The incidence of DRT was 4.6% in patients with IDE and 2.8% in those with CDE; the difference did not reach significance (P >.05).

• The MACCE rate was not significantly different between the groups: 7.7% in the IDE group vs 2.8% in the CDE group (P = .32).

• Provided there is continued antithrombotic therapy, DRT is not necessarily associated with thromboembolic events or poor clinical outcome.

Limitations

• The study, with relatively few patients, might be underpowered.

• Treatment regimens in the single-center study might not be representative of those used at other centers.

• A 6-month follow-up might not have been optimal for adequate assessment of long-term clinical outcomes of patients with IDE.

• Baseline echocardiographic features such as mitral-valve function, which may have had an impact on IDE, were not assessed.

Disclosures

• The study received no industry support. The authors declared that they have no conflicts of interest.

This is a summary of a preprint research study, Clinical Relevance of Incomplete Device Endothelialization After Left Atrial Appendage Closure, written by researchers at the Tongji University School of Medicine, Shanghai East Hospital, China on ResearchSquare provided to you by Medscape. This study has not yet been peer reviewed. The full text of this study can be found on researchsquare.com.

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