Use of LAA Occlusion in Low-Risk Patients Debated

During a didactic symposium at TCT 2015, experts debated the pros and cons of left atrial appendage (LAA) closure as an alternative to oral anticoagulation in patients with nonvalvular atrial fibrillation and at low risk for bleeding. The issue has taken on greater importance as physicians introduce the Watchman device (Boston Scientific Corporation) into everyday practice following its FDA approval in March 2015.

Device an alternative 

Arguing for the use of LAA closure as an alternative in low-risk patients, Saibal Kar, MD, of Cedars-Sinai Medical Center, Los Angeles, Calif., noted that more than 25% of patients stop taking oral anticoagulants within a few years for a variety of reasons, including the constant risk of bleeding, cost, drug failure, drug-drug interactions and compliance issues.

The safety and effectiveness of LAA closure have been established in studies of more than 30,000 patients overall and more than 2,400 in randomized trials or continued-access registries, he said. In the PROTECT AF trial, which evaluated the Watchman device vs. warfarin, there was no difference in the primary safety endpoint (procedure-related events and major bleeding) through 4 years, despite an increase in early events – such as pericardial effusion, device embolization, and periprocedural stroke – with the device. Moreover, Kar noted, complication rates have declined over time, even when looking at real-world data collected since approval, indicating that appropriate technique can minimize the risks of the procedure.

As for efficacy, he pointed out that pooled data from the PROTECT AF and PREVAIL trials demonstrated that the risk of stroke or systemic embolism was comparable between Watchman and warfarin. Although ischemic stroke was more common with Watchman, the difference was mitigated when procedural stroke was removed from the analysis, Kar said. Hemorrhagic stroke, CV/unexplained death and nonprocedure-related major bleeding were all reduced with Watchman. Additionally, in PROTECT AF, Watchman reduced disabling stroke, CV mortality and all-cause mortality through 4 years.

Thus, Kar said, the FDA approval of Watchman is appropriate for patients who are at increased risk for stroke and systemic embolism, are recommended for anticoagulation therapy, are deemed suitable for warfarin, and have an appropriate reason for seeking a nonpharmacologic alternative to warfarin.

Complications, challenges persist

Jai-Wun Park, MD, of Coburg Hospital, Coburg, Germany, countered that LAA closure should be limited to patients with contraindications to anticoagulation. Complication rates are expected to be higher in everyday practice, where patients have more challenging anatomy than in a trial setting, he said.

According to Park, LAA closure is associated with four major life-threatening acute complications — tamponade due to LAA perforation and transseptal puncture, device embolization, stroke due to clot or air embolism and pulmonary artery perforation — and one major life-threatening long-term complication — stroke due to device thrombosis. In addition, an FDA safety communication issued in July 2015 described six deaths and other serious complications related to the Lariat device (SentreHeart), which is used off-label for LAA closure. Three-quarters of the 45 adverse events reported to the FDA resulted in emergency heart surgery. As for Watchman, embolization rates have ranged from 0.4% to 1.3%, although those figures were not derived from real-world experience, Park said.

Park supports the concept of LAA occlusion, but he noted that it is not a simple procedure. The interest in LAA closure is growing among operators, although many are not skilled in structural heart device implants or transseptal puncture techniques, he said. Park acknowledged that technology is evolving and newer devices appear to carry lower risks of complications. But at this stage, he concluded, LAA closure should be limited to patients with contraindications to oral anticoagulation until more data about safety in the real world are available.

Disclosures:

• Kar reports relationships with multiple device companies.
• Park reports receiving grant/research support and consultant/honoraria fees from Lifetech, Occlutech and St. Jude Medical.