Despite recent advances and increasing adoption, certain issues with left atrial appendage occlusion (LAAO) remain, including the frequency of peridevice leak (PDL), which has been shown to confer a higher risk for subsequent ischemic events, warns a new review.
The state-of-the-art review, published online Monday and in the March 27 issue of JACC: Cardiovascular Interventions, presents an up-to-date review of the incidence, mechanisms, clinical impact, and management of PDL after percutaneous LAAO.
Led by Mohamad Alkhouli, MD, from the Mayo Clinic School of Medicine, Rochester, Minnesota, the team noted that while LAAO has emerged as a feasible stroke prevention strategy for selected patients with atrial fibrillation (AF), a key challenge is incomplete LAAO, which is often described synonymously as PDL.
“Initial data from the pivotal LAAO trials and prospective observational registries did not show an association between PDL and adverse events. Hence, the presence of PDLs (especially small ones) has largely been considered benign,” the team noted.
“However, recent studies documented a relationship between PDLs and subsequent thromboembolic events leading to a renewed interest in PDLs and their management.”
Alkhouli and colleagues noted that there is no consensus on the definition of PDL or the optimal method of its detection and sizing.
“In the published research, PDL has been defined as a residual communication between the left atrium and the LAA as determined on transesophageal echocardiography (TEE) or cardiac computed tomography (CT). However, the issue of PDL is highly nuanced, and uncertainties and controversies surrounding its detection and reporting remain,” they said, adding that the reported rate of PDL varies considerably according to the imaging modality selected for surveillance.
Indeed, they added that although TEE was used to detect PDL in clinical trials, other studies have suggested that CT is a more sensitive method to evaluate PDLs compared with TEE.
Despite a lack of clear consensus on the exact definition of PDL, the team notes that it is clear from numerous studies that PDL after LAAO are both common and associated with an increased risk of thromboembolic events.
The authors added that investigators who have sought to assess the clinical impact of PDL have faced several challenges: “First, the rate of thromboembolic events after LAAO is low. Therefore, discerning an independent impact of PDL requires a very large sample cohort and/or long-term follow-up.”
“Second, the cutoff of what is potentially significant PDL is arbitrary and varies across different sites (≥3, >3, and >5 mm). Third, the mechanism of PDL was not considered in most studies. Fourth, patients with large leaks often remain on anticoagulation or undergo PDL closure, and hence assessing the impact of residual leak in these patients is confounded by a significant treatment bias,” they said, adding that because of these limitations, most published studies on the clinical impact of PDL have been underpowered and/or inconclusive.
Treatment and Future Directions
“Once a PDL is diagnosed, the conundrum is whether leaks should be managed with watchful observation and frequent imaging, with long-term anticoagulation, or with prophylactic PDL closure,” said Alkhouli and colleagues.
“The decision is further complicated by the lack of consensus on which leaks are clinically significant (any leaks, leaks >3, ≥3, >5, and ≥5 mm), the absence of long-term efficacy data on PDL closure procedures, and the heightened risk for bleeding among these patients,” they added, noting that interventional approaches to close larger PDLs include the use of vascular plugs and cardiac occluders, detachable coils, radiofrequency ablation, or a combination of more than one technique.
Indeed, the team also noted that uncertainties remain regarding the long-term management of patients undergoing interventional PDL closure: “For example, there are no standardized protocols for postprocedural imaging surveillance or antithrombotic therapy after PDL closure,” they said, noting that previously published studies suggest that most patients who underwent PDL closure were treated with antiplatelet agents and underwent a single follow-up imaging study.
“Although the low rates of ischemic events reported in these studies support the potential efficacy of PDL closure, the small number of studied patients and the short follow-up duration precludes solid conclusions,” they said, warning that the impact of placing multiple devices in the LAA on the development of device related thrombus also needs to be investigated.
“Addressing PDL requires a holistic approach that primarily focuses on its prevention but also incorporates the emerging data on its various treatment options,” said the team, noting that computer simulation software has now been shown to aid in mitigating PDL and should be routinely used for preprocedural planning when feasible.
Meanwhile, selection of an LAA occluder should consider the likelihood of achieving complete seal with that particular device, they said.
“We suggest that the assessment of a PDL consider both the leak’s dimensions and its mechanism. If the leak is determined to be ‘clinically relevant,’ decisions on anticoagulation or PDL closure should consider the individual ischemic vs bleeding risks and the limited long-term data on PDL closure. Furthermore, framing of those risks should reflect both the relative and absolute rates of ischemic events associated with PDL reported in the published research,” concluded Alkhouli and colleagues.
Alkhouli M, De Backer O, Ellis CR, et al. Peridevice Leak After Left Atrial Appendage Occlusion: Incidence, Mechanisms, Clinical Impact, and Management. JACC Cardiovasc Interv 2023;16:627-642.
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