Watchman in the Real World: Reports on Use in High-Risk Patients and Overall Safety

Recaps of three studies from Cleveland Clinic’s experience to date

By Oussama Wazni, MD, MBA, and Samir Kapadia, MD

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Since its FDA approval in March 2015, the Watchman™ left atrial appendage closure device has been implanted into nearly 50,000 patients with nonvalvular atrial fibrillation (AF) as a nonpharmacologic alternative for reducing stroke risk.

At Cleveland Clinic, we have performed more than 200 of those procedures, with excellent results. Members of our team reported on our experience with the Watchman in three study presentations at the Heart Rhythm Society’s 39th Annual Scientific Sessions this week, and we hope our findings (outlined below) may help expand the use of this device to benefit a wider range of patients.

Use in patients with prior intracranial hemorrhage

Both of the two original trials of the Watchman device — PROTECT-AF and PREVAIL — excluded patients with AF who had perceived contraindications to oral anticoagulation, including prior intracranial hemorrhage.

We hypothesized that these patients might actually stand to gain particular benefit from left atrial appendage closure, as it would spare them from the need for long-term anticoagulation even though they would be exposed to the short-term anticoagulation required after Watchman placement to prevent thrombus formation on the device.

In Cleveland Clinic’s multidisciplinary Atrial Fibrillation Stroke Prevention Center, we have now implanted the Watchman in more than 40 patients with AF who had prior intracranial hemorrhage and would therefore have been excluded from the pivotal trials. All patients receiving the device are enrolled in a prospectively maintained registry.

Despite continuation of anticoagulation for six weeks postimplantation in all patients, there have been no procedural complications and no intracranial bleeds. One patient had minor bleeding without adverse sequelae.

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Transesophageal echocardiograms at 45 days showed no peridevice leak or device-related thrombi. There were no strokes and no deaths at mean follow-up of 13 months.

To accomplish these results, our cardiac electrophysiology team works closely with our neurologist and neurosurgeon colleagues to screen and manage patients. The neurological team typically advises that Watchman implantation be delayed for a few months after the bleed, and they use MRI to ascertain whether some patients are at such high bleeding risk that they simply cannot be exposed to any anticoagulation. So far we haven’t encountered any such patients.

The study patients had an average CHADSVASC score of 4.9 and an average HAS-BLED score of 4.1. In all cases, we determined in joint decision-making with the patients that the Watchman’s stroke prevention benefit outweighed the risk of short-term anticoagulation so that they could avoid long-term oral anticoagulation. This approach has paid off thus far.

In fact, we believe it’s actually these patients, who were excluded from the original Watchman trials, who may derive the most benefit from left atrial appendage closure.

Higher stroke risk, greater benefit?

In the PREVAIL trial, the Watchman was noninferior to warfarin for ischemic stroke prevention or systemic embolization after seven days, one of two co-primary end points for efficacy. Overall noninferiority — the other co-primary efficacy endpoint — wasn’t achieved. However, safety of the procedure had improved significantly in the five years since PROTECT-AF, and PREVAIL did achieve the prespecified safety goal.

We wondered whether the Watchman might provide greater stroke prevention in patients with higher baseline stroke risk. So, in contrast to the average CHADSVASC score of about 4 in PREVAIL, we assessed outcomes for over 100 Watchman recipients in our registry with a CHADSVASC scored of 5 or greater.

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At one year, just 2.8 percent of patients had experienced a stroke. This compares favorably to the estimated annual stroke risk of about 12 percent for patients in this population not on anticoagulation and the greater than 4 percent risk for those on warfarin. In addition to giving us reassurance that the Watchman decreases ischemic stroke, this finding provides further information about the patients most likely to benefit from left atrial appendage closure.

Encouraging intraprocedural safety

Among the more than 200 patients who have been implanted with the Watchman at Cleveland Clinic, there have been no pericardial tamponades, procedure-related strokes, device embolizations or procedure-related deaths. In contrast, in a recent published review of nearly 4,000 U.S. implantations, rates of these intraprocedural complications were 1.02 percent, 0.078 percent, 0.24 percent and 0.078 percent, respectively. Of course, those rates are very low overall, as more and more centers gain experience with the device.

Cleveland Clinic is also involved in trials of two other left atrial appendage closure devices that may offer further advantages for patients with nonvalvular AF. Stay tuned for what we believe is an exciting future of new options for this patient population.

Dr. Wazni is Section Head of Cardiac Electrophysiology and Pacing, and Dr. Kapadia is Section Head of Interventional Cardiology, both at Cleveland Clinic.