LAA Closure With Amplatzer Appears Safe, Effective in A-fib Patients

In high-risk patients with nonvalvular atrial fibrillation (A-fib), left atrial appendage (LAA) occlusion using a cardiac plug device can be safely performed and effectively prevents long-term stroke, according to a study published online October 30, 2014, ahead of print in EuroIntervention. But the overall lack of evidence base could derail any hope for approval from the US Food and Drug Administration (FDA) in the near future, according to an outside source.

Stroke Prevention With Minimal Complications

Technical success was 95.5% (n = 128), with implantation failure consistently related to unfavorable LAA anatomy—multiple proximal lobes and a shallow landing zone. Additionally, the procedural success rate was 93.3%, as there was one instance of pericardial effusion and 2 occurrences of cardiac tamponade. There was no procedural stroke or device embolization, but 6 patients experienced minor procedural complications.

After a mean follow-up of 680 days (238 patient-years), three-quarters of patients were taking aspirin, 14% were on clopidogrel, and 10.9% were not receiving any antithrombotics. Thirty- three events were recorded in 28 patients, 8 of whom died. All deaths were unrelated to the device or implantation procedure. Five cerebral ischemic events occurred during follow-up, including 2 nonfatal strokes and 3 transient ischemic attacks. Observed event rates were lower than would be expected based on patients’ risk scores (table 1).

Moreover, among 64 patients followed out to 2 years, all but 1 remained free from ischemic stroke.

Intracranial bleeding was reported in 1 patient on an “unduly high dose of triple antithrombotic therapy following an erroneous prescription by the patient’s general practitioner,” the authors note. Two additional patients had major extracranial bleeding (both gastroenteric), resulting in an overall major bleeding rate of 2.3% and an annual major bleeding rate of 1.3%.

In the 67 patients who had transesophageal echocardiography (mean 9.7 months after implant), 1 major and 6 nonsignificant residual leaks were observed.

Implantation Depends on Suitable Anatomy

“[LAA occlusion] is a safe and effective therapy for stroke prevention in [nonvalvular A-fib] patients who are at high risk for ischemic stroke and bleeding and are not suitable for long-term [oral anticoagulation],” Dr. Berti and colleagues write, especially since “the stroke rate assessed over a period of up to 4 years of follow-up remains lower than the cohort’s risk-predicted stroke rate.”

The annual major bleeding rate “closely resembles the bleeding rate reported for large cohorts taking aspirin,” the authors report, adding that the overall therapy-related major bleeding rate of 2.6% “represents a beneficial outcome of [LAA occlusion],” as it was expected to be 3.1%.

Nevertheless, the researchers acknowledge that device implantation is heavily dependent on suitable anatomy. “Different types of appendage might require specific implant techniques,” they write, adding that “it might still be prudent to abstain from implantation in certain anatomies.”

Dr. Berti and colleagues say that although their findings need confirmation from a large randomized trial with a more uniformly treated cohort, their therapeutic approach is consistent with the clinical practice.

Evidence Base ‘Woefully Lacking’

In a telephone interview with TCTMD, Zoltan G. Turi, MD, of Cooper University Hospital (Camden, NJ), said that this analysis is “one of a myriad of observational studies that have all said the same thing,” and the “good news” is that it is the largest.

The “bad news,” he continued, is that the device “has been marketed for a number of years and is woefully lacking in evidence base.”

For example, Dr. Turi compared this study’s 238 patient-years with the 6,000-plus patient-years logged with the Watchman LAA Closure Device (Boston Scientific), a substantial proportion of them in a randomized clinical trial. “When we actually have randomized control groups, the event rates have been dramatically less than what was predicted, most notably [in] the PREVAIL trial,” he said.

Nonetheless, this study is “particularly important” since a recent FDA advisory panel came back with a split vote over whether to approve Watchman. “The FDA is on the cusp of making a decision that may well affect our ability to use these devices for a long time,” Dr. Turi observed. “If FDA approves Watchman, I think it will make it easier to get this device and a slew of others in the pipeline. But if FDA does not approve Watchman, the lack evidence base [will be partly to blame].”

Dr. Turi said the long road to approval for Watchman has been “unprecedented,” adding that he “sympathize[s] with the difficulty that the FDA has in terms of where to go from here. At the same time, I'm a clinician who would like to have the technology available for at least a subset of patients.”

 

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Source:
Santoro G, Meucci F, Stolcova M, et al. Percutaneous left atrial appendage occlusion in patients with non-valvular atrial fibrillation: implantation and up to four years follow-up of the AMPLATZER Cardiac Plug. EuroIntervention. 2014;Epub ahead of print.

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