Watchman LAA Effective in Patients Contraindicated for Warfarin

MIAMI BEACH, FLA.—Two presentations at TCT 2012 demonstrated that use of the Watchman device for left atrial appendage (LAA) closure in patients contraindicated for warfarin is safe and feasible. The device, which is currently awaiting FDA approval, also was shown to be noninferior to warfarin among patients aged 75 years and older.

ASAP registry study

In a multicenter ASAP registry study, researchers led by Horst Sievert, MD, PhD, of CardioVascular Center Frankfurt in Germany, evaluated the Watchman (Atritech, Plymouth, MN), for LAA closure in 142 patients contraindicated for warfarin.

The ASAP protocol was similar to PROTECT AF, in which the Watchman device was implanted with 45-day warfarin treatment.

In comparing registry results with PROTECT AF, researchers observed no significant difference in incidence of death (5% for ASAP vs. 3.2% for PROTECT AF), stroke (2.3% vs. 2%), ischemic stroke (1.7% vs. 1.9%), or hemorrhagic stroke (0.6% vs. 0.3%) per 100 patient-years.

Rates of device thrombus and other adverse events were similar between the two trials. Sievert and colleagues also reported a 77% reduction in stroke in the ASAP study. The researchers observed a stroke rate of 1.7% per year, while historical comparisons projected an expected stroke rate of 7.3% per year based on mean CHADS2 score of 2.8. According to Sievert, the results confirm that LAA closure with the Watchman is at least as good

PROTECT AF subanalysis

Presenting data from a subanalysis of PROTECT AF, Saibal Kar, MD, of Cedars-Sinai Medical Center in Los Angeles, said the

Watchman was associated with outcomes similar to warfarin among high-risk AF patients aged 75 years or older.

 PROTECT AF included 305 patients aged 75 years or older with CHADS2 score ≥ 1. Of these, 190 were randomized to LAA closure with the Watchman (164 underwent successful implantation) and 115 patients were randomized to warfarin control. For the subanalysis, Kar and colleagues used proportional hazard models to compare the composite primary efficacy endpoint (stroke, systemic embolism, and cardiovascular/unknown death), stroke incidence and all-cause mortality in the device and control groups.

At an average follow-up of 27 months, patients who underwent device implantation experienced efficacy outcomes—expressed as the percentage of patients who experienced adverse events per year—that were at least as good as those assigned to warfarin control (see Figure).

“It met the noninferiority margins very clearly … but it was not superior,” Kar observed.

Overall rates of major bleeding were higher in the device group than the control group (6.1 vs. 5.1 events/patient-years), but non-procedure related major bleeding rates were lower in the device group (3.3 vs. 5.1 events/patient-years).

“These results may confirm that LAA closure with the Watchman device is a reasonable alternative to anticoagulation for patients (age 75 years or older),” Kar said.