'Striking' Difference in Adverse Events in Women With Watchman LAAO

Patrice Wendling

August 13, 2021

Women have more in-hospital complications than men and double the risk for major adverse events after left atrial appendage occlusion (LAAO) with the Watchman device, according to new National Cardiovascular Data Registry (NCDR) LAAO Registry data.

In-hospital mortality was also twofold higher among women than men and hospital stay was longer. Even after adjustment for potential confounders, these relationships still exist, Douglas Darden, MD, University of California, San Diego, and colleagues reported online in JAMA Cardiology.

"I think this article certainly highlights — specific to a procedure that has gained more popularity and will become more commonplace in cardiovascular practice — that operators and patients need to pay more attention that women may be at more risk for adverse events and mortality," senior author Jonathan Hsu, MD, also from UCSD, told theheart.org | Medscape Cardiology.

Possible explanations for the disparities include anatomic differences between the sexes, such as smaller vessel diameter, thinner myocardial wall, and a more friable LLA in women; increased frailty; and clinician inexperience, the authors suggest.

"It could be something as simple or as specific as thinness of tissue or friability of tissue that may predispose women more than men to perforation or other risks that may put them at risk for adverse events specifically," Hsu said.

Commenting further, he said, "I think we would be remiss not to mention the fact that part of this association may unfortunately be a disparity in care that women as a specific sex may receive,” he said.

Indeed, postimplantation women had higher adjusted odds of receiving a direct oral anticoagulant only (odds ratio [OR], 1.07, = .02) and warfarin only (OR, 1.12; < .001), and lower odds of receiving clinical trial-recommended combined oral anticoagulants plus single antiplatelet therapy (OR, 0.91; < .001).

"This article highlights the fact that in all aspects we need to pay attention that women receive as high-level, guideline-driven care as men," Hsu said.

First author Darden pointed out in an email that women suffer disproportionately from atrial fibrillation (AF), compared with men, with worse quality of life and higher risk for stroke. So "it's only natural to seek further treatment in order to decrease that risk, specifically LAAO with Watchman."

Despite the fact that women are known to be at greater risk for adverse events after invasive procedures, including AF ablation and TAVR, however, little is known about sex differences with LAAO, as the LAAO clinical trials only included about 30% women, he said.

Two 2021 papers zeroing in on these sex differences produced mixed results. An American report in roughly 9200 patients reported a higher risk for major in-hospital events in women after receipt of Watchman implants, whereas a German report found similar safety and efficacy among 387 consecutive patients, regardless of sex.

The present study involved 20,388 women and 28,969 men implanted with the Watchman device between January 2016 and June 2019 in the NCDR registry, the largest LAAO registry with adjudicated events with participation mandated for Medicare coverage.

The women were older (mean age, 76.5 vs 75.8 years), had a higher mean CHA2DS2-VASc score (5.3 vs 4.5), and more likely to have a high fall risk as an indication for LAAO (39.8% vs 33.5%).

Further, women were more likely than men to have paroxysmal atrial fibrillation and uncontrolled hypertension, but less likely to have congestive heart failure, diabetes, and coronary artery disease.

After multivariable adjustment, all but one of the primary outcomes was significantly worse in women vs men:

  • Aborted or cancelled procedure: 3.0% vs 2.9% (OR, 1.01; = .87)

  • Any adverse event: 6.3% vs 3.9% (OR, 1.63; < .001)

  • Major adverse event: 4.1% vs 2.0% (OR, 2.06; < .001)

  • Hospital stay more than 1 day: 16.0% vs 11.6% (OR, 1.46; < .001)

  • Death: 58/0.3% vs 37/0.1% (OR, 2.01; = .001).

The authors point out that device-related adverse events are lower than in the PROTECT-AF and PREVAIL clinical trials of the Watchman, with 0.8% of patients developing a pericardial effusion requiring drainage and 1.2% having major bleeding, down from highs of 4.8% and 3.5%, respectively, in PROTECT-AF.

Although promising overall, adverse events among women were driven by higher rates of both pericardial effusion requiring draining (1.2% vs 0.5%; < .001) and major bleeding (1.7% vs 0.8%; < .001).

Commenting for theheart.org | Medscape Cardiology, John Mandrola, MD, Baptist Health, Louisville, Kentucky, expressed concern that despite its increasing popularity, the rate of serious complications appears to be increasing for the preventive procedure. "That's peculiar because you'd expect increased experience and device iterations to decrease complications. And the NCDR data surely undercounts the real rate of adverse events because it only includes in-hospital complications."

Based on the current data, he observed that there's a 3% chance for a major complication overall, with the typical female Watchman patient facing a 6% chance of any adverse event and 4% risk for a major adverse event during her hospital stay alone.

"The striking difference in complications in women is a super important observation because higher upfront risk has an even more negative effect on the harm–benefit calculus of this procedure," Mandrola said.

"Some of the increased harm in women may have been due to the slightly higher rate of comorbid conditions, but that is real-life," he said. "Registry data like this is extremely valuable because, unlike the carefully selected randomized trial, registries reflect what is actually being done in practice."

Hsu agreed that the absolute numbers are concerning. Nevertheless, "it doesn't necessarily sound an alarm that our adverse events are worse in contemporary practice or that adverse events continue to increase. But, in general, it just points to the fact that there is this inherent larger risk in women, compared to men, and that we need to, first, figure out why and, second, we need to figure out how to improve."

Strategies to mitigate procedural risk included ultrasound-guided venous access, preprocedural imaging, improved proficiency with LAAO devices, and continued development of safer devices, they note.

Despite the more generalizable nature of registry data, "the results of this study should not result in differing sex-based thresholds for LAAO implant," the authors conclude.

The study was supported by the American College of Cardiology Foundation's NCDR. Hsu reports receiving personal fees from Medtronic, Boston Scientific, Abbott, Biotronik, Janssen Pharmaceutical, Bristol Myers Squibb, Pfizer, Biosense Webster, Altathera Pharmaceuticals, and Zoll Medical; grants from Biotronik and Biosense Webster; and holding equity interest in Acutus Medical and Vektor Medical outside the submitted work. Darden reports no relevant financial relationships. Mandrola is a regular contributor to Medscape Cardiology.

JAMA Cardiol. Published online August 11, 2021. Abstract

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