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Randomized trials, observational studies differ on LAA occlusion vs. drug therapy for stroke prevention
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Randomized controlled trials did not demonstrate left atrial appendage occlusion devices to be superior to novel oral anticoagulants for stroke prevention in patients with atrial fibrillation, but observational studies suggest they might be, according to data published in Heart Rhythm.
Researchers conducting a systematic review and meta-analysis determined that in observational studies, left atrial appendage (LAA) occlusion devices were associated with lower rates of thromboembolic and hemorrhagic events compared with drug therapy.
“There is a trend toward decrease in thromboembolic and major bleeding event rates with prolonged follow-up duration after the implantation of a LAA [occlusion] device. Our findings suggest that priority might be given to the LAA [occlusion] device when determining stroke prevention strategy for patients with AF, especially in the elderly and high-risk population,” the researchers wrote.
Xin Li, PhD, and colleagues conducted a systematic review of randomized controlled trials and observational studies on novel oral anticoagulants (NOACs) and LAA occlusion devices, and then performed a network meta-analysis and meta-proportion analysis to evaluate differences in safety and efficacy of stroke prevention.
Overall, six randomized controlled trials and 27 observational studies were included in the analyses. Efficacy outcomes included stroke in the randomized controlled trials and thromboembolic events in the observational studies. Major bleeding event rate and major adverse event rates were measured as safety outcomes.
Randomized controlled trial s
According to the network meta-analysis of the randomized controlled trials, overall, NOACs were better for stroke prevention (probability of being the best, 60%) than an LAA occlusion device (Watchman, Boston Scientific; OR = 0.86; 95% CI, 0.34-1.75).
Dabigatran (Pradaxa, Boehringer Ingelheim) 150 mg was the most effective at preventing stroke, with a rank probability of 36%. ORs for dabigatran based on all pairwise comparisons ranged from 1.23 vs. apixaban (Eliquis, Bristol-Myers Squibb/Pfizer) to 1.77 vs. edoxaban (Savaysa, Daiichi Sankyo) 30 mg.
Both edoxaban 30 mg and the Watchman device were the least effective in stroke prevention compared with warfarin (OR = 0.89). However, the Watchman device was the most effective in hemorrhagic stroke reduction (probability of being the best, 35% vs. 0% for warfarin).
In terms of major bleeding, edoxaban 30 mg (OR vs. warfarin = 2.16) and the Watchman device (OR vs. warfarin = 1.82) were associated with fewer events. The ORs for rivaroxaban (Xarelto, Janssen Pharmaceuticals) and warfarin vs. the Watchman device were 0.51 and 0.55, respectively. Combined together, novel oral anticoagulants were inferior to LAA occlusion devices (OR = 0.66 vs. Watchman), with warfarin faring the worst (OR = 0.52 vs. Watchman), according to Li, from the department of cardiology, Beijing Anzhen Hospital, Capital Medical University, National Clinical Research Center for Cardiovascular Diseases, Beijing, and colleagues.
Observational studies
The meta-analysis of the observational studies, however, suggested that LAA occlusion devices are effective at preventing stroke compared with drug therapy.
In a pooled analysis, the devices had a lower stroke rate than NOACs (1.8 vs. 2.4 events/100 person-years for pooled thromboembolic event rate). The Watchman and Amplatzer (St. Jude Medical) devices had similar stroke outcomes, with pooled thromboembolic event rates of 1.7 and 1.8 events per 100 person-years, respectively. In addition, a subgroup analysis revealed the pooled thromboembolic event rate for LAA occlusion devices decreased over time (2.1 events per 100 person years at 1 years; 1.8 events per 100 person-years at 1 to 2 years; and 1 event per 100 person-years at more than 2 years).
LAA occlusion devices in the observational studies also showed a lower pooled major bleeding event rate than the NOACs (2.2 vs. 2.5 events per 100 person-years). However, both the devices and drug therapies had a similar intracranial hemorrhage rate (0.343% per year). Bleeding event rates in the LAA occlusion device group were lowest more than 2 years after implantation, the researchers wrote.
Combined analysis
An overall analysis of both randomized controlled trials and observational studies revealed that LAA occlusion devices had a stroke rate of 1.6 events per 100 person-years compared with NOACs, which had a stroke rate of 2 events per 100 person-years. Warfarin had the highest stroke rate (3.2 events per 100 person-years). Major bleeding event rates also were lower for LAA occlusion devices than for novel oral anticoagulants (2.1 vs. 2.6 events per 100 person-years) and for warfarin (3.6 events per 100 person-years), the researchers found.
In the meta-proportion analysis, the rate of periprocedural major adverse events after LAA occlusion device implantation was 6%, with the Watchman device having a lower rate than the Amplatzer device (4.1% vs. 6.5%).
The researchers wrote that head-to-head randomized controlled trials are necessary to confirm the findings. – by Tracey Romero
Disclosure: Li reports no relevant financial disclosures. Please see the full study for a list of all other researchers’ relevant financial disclosures.
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