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Optimization of left atrial pressure prior to left atrial appendage (LAA) closure -- through volume loading with saline -- may be linked to improved closure device sizing, a single-center study found.

After a fluid bolus, the LAA widened by 1.9 mm (P<0.0001) and deepened by 2.5 mm (P<0.0001) on average in patients who had fasted prior to LAA measurement by transesophageal echocardiography (TEE).

This expansion "corresponds to upsizing of the currently available devices by an entire size" which can "result in better device stability," , of Vancouver General Hospital, and colleagues reported in the December issue of JACC: Cardiovascular Interventions.

"Establishing the physiological maximum width of the LAA enables the operator to select the largest device that can be accommodated by the LAA, which is likely to have the least risk of leak, embolization, and perforation," they wrote. "Although the clinical significance of residual leak has not yet been established, many believe that large residual LAA leaks can contribute to higher stroke risk, as was seen with surgical LAA closure."

"Selecting a device that remains 8% to 20% compressed when the LAA is at its maximal size is of paramount importance," they added.

, of Swedish Heart and Vascular in Seattle, and colleagues agreed, writing in an accompanying editorial that "judicious intravenous fluid loading should be part of the procedural steps for LAA closure."

Fluid loading is an additional step and could risk pulmonary edema for patients with low ejection fraction, the editorialists noted. "However, these challenges are surmountable; the patient can have fluids given before procedure. In addition, the fluids may also make it easier to perform a safe transseptal puncture."

The study included 31 atrial fibrillation patients who underwent LAA occlusion between 2014 and 2015. Their devices were sized according to TEE measurements of the LAA orifice taken after fasting and volume loading.

The authors acknowledged that they "were not able to assess the effect of volume loading on clinical outcomes," citing the lack of a control group in the study. They warned, however, that "overzealous oversizing" of devices can lead to increased risks of perforation and device embolization and "should be avoided."

A separate study published alongside Saw's in JACC: Cardiovascular Interventions confirmed that the Watchman LAA closure device is after implantation.

For patients at high risk for both stroke and bleeding, the annual rates of death, stroke, transient ischemic attack, and intracranial hemorrhage were 3.5%, 0.7%, 0.7%, and 1.1%, respectively, in individuals implanted with the Watchman.

These numbers "show that percutaneous LAA closure with the Watchman device can be performed with high procedural success and a low rate of severe procedure-related adverse events," according to , of CardioVascular Center Frankfurt in Germany, and colleagues.

The single-center study included 102 atrial fibrillation patients who underwent LAA closure with the Watchman device between 2006 and 2010. Individuals received post-procedural anticoagulation therapy with vitamin K antagonists, dual antiplatelet therapy, or both for 6 months.

Over the mean follow-up period of 3 years, 8.8% of patients experienced procedure-related adverse events, such as pericardial effusion. Additionally, severe bleeding complications requiring hospitalization occurred in 2.1% of patients per year.

The data "confirm the safety and efficacy of LAA occlusion with the Watchman device for stroke protection, irrespective of the post-procedural anticoagulant regime," the authors concluded, calling LAA occlusion "a reasonable alternative to oral anticoagulation."

Several questions surrounding LAA closure remain to be answered, however. "What is the best device to close the door, which is actually oval in most patients?," , and , both of the Mayo Clinic in Rochester, Minn., asked in an accompanying editorial. "This does have important implications because the current devices are circular, and when placed in an oval orifice may lead to persistent leaks."

Nonetheless, the editorialists wrote that "LAA occlusion technology is transformational" and offers a potential treatment for "patients who have very limited options for stroke prevention."

From the American Heart Association: