Recasting Endovascular Coils to Seal Post-LAAO Leaks

Patrice Wendling

January 23, 2020

Detachable endovascular coils may provide an alternative approach to sealing residual leaks after left atrial appendage occlusion (LAAO), a small feasibility study suggests.

LAA coiling completely sealed or reduced residual leaks to 2 mm or less in 28 of 30 consecutive patients with atrial fibrillation and high thromboembolic and bleeding risk.

At 60-day follow-up, five patients had moderate device leak, three of whom underwent successful repeat coiling. There were no device-related thrombi and no coil migration or embolization.

The overall complication rate was 6.1% (2/33). One patient suffered a pericardial tamponade requiring a pericardial window and a second had a small pericardial effusion treated with pericardiocentesis.

"The high success rate and acceptable safety profile of LAA coiling may justify its use in larger studies to assess whether and in which AF populations achieving complete LAA closure enhances stroke prophylaxis," the authors reported January 15 in JACC Cardiovascular Interventions.

Although endovascular coiling has been used to treat a range of conditions from brain aneurysms to patent ductus arteriosus, the TREASURE study is the first to report on its use after incomplete LAA closure.

About 25% to 30% of patients have a visible leak after treatment with the Lariat device (SentreHeart), with similar rates observed in those receiving endovascular plugs like the Amulet (Abbott) and Watchman (Boston Scientific), lead author Domenico Della Rocca, MD, Texas Cardiac Arrhythmia Institute at St. David's Medical Center in Austin, said in an interview.

"There are some limitations of the anatomy and morphology of the appendage and the left atrium, but also some limitations of the technologies that are available now," he said. "So unfortunately, there are still a significant number of patients who have residual leak."

Also, there is not a clear correlation between the size and presence of leaks and thromboembolic events. It's common practice to continue anticoagulation if a leak is larger than 5 mm in diameter, but this cut-off is "completely arbitrary," Della Rocca said.

The researchers selected patients for TREASURE who had significant residual LAA leak, a high thromboembolic and bleeding risk profile, and at least one of the following criteria: contraindications to long-term oral anticoagulation therapy, need for prolonged dual antiplatelet therapy, and/or a history of thromboembolic events after LAA closure.

On baseline transesophageal echocardiography (TEE), 10 patients had leaks that were 5 mm or larger and 20 had 3- to 4-mm leaks.

Most patients (73.3% male; mean age, 72 years) had undergone LAA occlusion/exclusion procedures with the Watchman (n = 25) device, but the Amulet was used in two and the Lariat in three. Their mean CHA2Ds2-VASc score was 4.4, and mean HAS-BLED score was 3.6. Median follow-up was 54 days.

The procedures were performed under general anesthesia in the EP lab, and both TEE and intracardiac echocardiography were used continuously to guide trans-septal puncture and placement of the coils.

The average procedure time was 76 minutes, fluoroscopy time 21 minutes, and volume of iodinated contrast used was 80 mL.

Coil deployment led to an average reduction in leak size of 86.3% (< .001). A median of three coils were used in each procedure.

"The main challenge when you're doing leak closure with coils is to understand how to select the size of the coils because you are not just closing the leak, you need to first fill the residual volume inside the appendage," Della Rocca observed. "So you start filling this thrombus inside the appendage with one or more coils, and then you move toward the leak and then seal the leak."

With more experience, the team optimized the procedure. "So basically now we select the coils using longer coils to cover a wider space at the beginning and then we optimize the closure with smaller coils so we can be more precise," he said. "We now have more than 100 leaks closed with coils and basically success is almost 100%."

Of the 17 patients taking an oral anticoagulant at baseline, only two were kept on OAC at follow-up, owing to the presence of residual moderate leak.

"There are several factors that justify this technique; it's not only reducing the risk of stroke, it's also avoiding long-term oral anticoagulation in patients who are very high risk, not only for stroke, but also bleeding," Della Rocca said.

Nevertheless, "I want to underline the fact that not all patients with 3- to 4-millimeter leaks need to be treated," he added. "As I said before, selection is very important," as well as the risk profile.

In a linked editorial, Mohamad Alkhouli, MD, Mayo Clinic, Rochester, Minnesota, says: "An evident contribution of this study is its addition of a useful tool to our interventional armamentarium for treating persistent post-LAAO leaks. However, the more important contribution of this study may be its underscoring of the enormous deficits in our understanding of post-LAAO leaks overall."

Fundamental questions include why leaks occur after LAA occlusion, whether they increase the risk for adverse events, and whether percutaneous leak closure mitigates those potential risks.

Speaking to | Medscape Cardiology, Alkhouli highlighted the importance of refining LAAO technology so leaks don't happen in the first place.

"A lot of the appendages are oval, circular, funnel shaped, and we really just have a circular device, so at the end of the day, some patients are going to have leak. The question is how to minimize that," he said. "They're working on that with the device design and the steerable sheath. So I think we are going to see less of that, but it begs the question: Do we really need to do those things to fix the leak or should we take a step back and try to understand it first?"

Alkhouli noted that there are now more than 100,000 LAA closures with the Watchman device alone worldwide. "If they're saying it's 25%, 30% [who have leaks], that means there are 25,000 patients who have some sort of a leak, and still nobody can tell which one is significant and which one is not."

A joint study by Mayo, the American College of Cardiology, and Yale University is underway to look at a national registry of LAAO in 40,000 to 50,000 patients, Alkhouli said. "So we will know more in the future."

Della Rocca and Alkhouli report no relevant conflicts of interest.

J Am Coll Cardiol Intv. Published online January 15, 2020. Abstract, Editorial

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