Feature | Atrial Fibrillation | November 02, 2017

Mixed Results in PREVAIL Trial Comparing Five-Year Data for LAA Closure Compared to Warfarin

Study looked at patients with nonvalvular atrial fibrillation and included a combined meta-analysis with PROTECT AF at TCT 2017 

The Watchman LAA occluder PREVAIL Trial 5-year results were presented at the 2017 TCT meeting.

November 2, 2017 – Five-year results from the PREVAIL Trial comparing left atrial appendage closure (LAAC) with the Boston Scientific Watchman device to warfarin in patients with nonvalvular atrial fibrillation found that the first composite co-primary endpoint of stroke, systemic embolism (SE), or cardiovascular/unexplained death did not achieve noninferiority. However, the second co-primary endpoint of post-procedure ischemic stroke/SE did achieve noninferiority. When combined with the five-year outcomes of the PROTECT AF trial a meta-analysis demonstrated that LAAC provides stroke prevention comparable to warfarin, with additional reductions in major bleeding, particularly hemorrhagic stroke and mortality.

Findings were reported at the 2017 Transcatheter Cardiovascular Therapeutics (TCT) scientific symposium and published simultaneously in the Journal of the American College of Cardiology.

“Beyond PROTECT AF, PREVAIL is the only other completed randomized clinical trial comparing any LAAC device with an oral anticoagulant,” said Saibal Kar, M.D., director of cardiovascular intervention center research at Cedars-Sinai Medical Center. “Based on the combined results of these two studies, left atrial appendage closure is a reasonable strategy for stroke prophylaxis for patients who are poor candidates for long-term oral anticoagulation.”

Because of identical efficacy endpoint definitions in both the PROTECT AF and PREVAIL trials, and the near-identical eligibility criteria, data from both trials were pooled for a patient-level meta-analysis. The PROTECT AF and PREVAIL trials enrolled 707 and 407 patients, respectively, who were randomized 2:1 to the LAAC and warfarin arms. In both trials, patients were followed for the protocol-defined maximum time period of five years, ending in 2013 and 2017. Baseline patient characteristics were similar in both studies.

For the PREVAIL trial, all endpoints required the inclusion of the PROTECT AF informative prior, resulting in a calculated 18-month rate of the first coprimary endpoint (composite of stroke, systemic embolism (SE), or cardiovascular/unexplained death) of 0.066 with LAAC versus 0.051 for warfarin, yielding a mean 18-month rate ratio of 1.33 (95% credible interval: 0.78 to 2.13). It did not achieve noninferiority (posterior probability for noninferiority = 88.4%). However, the second coprimary endpoint of post-procedure ischemic stroke/SE did achieve noninferiority (posterior probability for noninferiority = 97.5%). The calculated 18-month rate for the second coprimary efficacy endpoint was 0.0255 in the LAAC group versus 0.0135 in the warfarin group (rate difference 0.0120; 95% credible interval: -0.0036 to 0.0275) At five years, the warfarin arm maintained an unexpectedly low ischemic stroke rate (0.73%), as compared with other studies examining such a regimen.

In the meta-analysis of PROTECT AF and PREVAIL with five-year follow-up, the composite endpoint was similar between groups (HR: 0.820; P=0.27), as were all-stroke/SE (HR: 0.961; P= 0.87). The ischemic stroke/SE rate was numerically higher with LAAC, but this difference did not reach statistical significance (HR: 1.71; P=0.080). However, differences in hemorrhagic stroke, disabling/fatal stroke, cardiovascular/unexplained death, all-cause death, and post-procedure bleeding favored LAAC (HR: 0.20; P=0.0022; HR: 0.45; P=0.03; HR: 0.59; P=0.027; HR: 0.73; P=0.035; HR: 0.48; P=0.0003, respectively). Therefore, the meta-analysis demonstrates comparable efficacy and stroke rates with no significant difference across subgroups, no significant differences in ischemic stroke rates versus warfarin, and significant, superior reductions in disabling strokes, non-procedural bleeding, and mortality.

The PREVAIL trial was funded by Boston Scientific. Kar reported that he received research grants from and served as a consultant for Abbott Vascular and Boston Scientific; has served as a member of the advisory board for left atrial appendage closure; is the national principal investigator of the Continuous Access Registries (CAP & CAP2); and has served as a proctor for Boston Scientific.

For more information: www.crf.org

 

Related Content

TCT 2017 Late-breaking Clinical Trial Presentations

Related Content

Boston Scientific's Apama multi-electrode ablation balloon to treat atrial fibrillation.

Boston Scientific's Apama multi-electrode ablation balloon to treat atrial fibrillation. The technology allows different energies to be used for each electrode to prevent damage to the esophagus or other underlying critical structures. 

Feature | Atrial Fibrillation | January 15, 2018 | Dave Fornell
The development of atrial fibrillation (AFib or AF) ablation technologies over the past 20 years has been a constant
Heart Rhythm Society Partners With WebMD Education to Increase Atrial Fibrillation Awareness
News | Atrial Fibrillation | January 02, 2018
The Heart Rhythm Society (HRS), in partnership with WebMD Education, announced in December the launch of a free, online...
The Boston Scientific Rhythmia Mapping System produces higher-density voltage maps without increasing overall procedure time.

The Boston Scientific Rhythmia Mapping System produces higher-density voltage maps without increasing overall procedure time. It was the first of a new generation of high-density mapping systems to be introduced.

Feature | Atrial Fibrillation | December 18, 2017 | Kenneth Stein, M.D. FACC FHRS
When I began practicing as an electrophysiologist in 1994, the dream of successfully using cardiac catheter ablation
Acutus dipole density EP mapping for ablation procedures.

The FDA recently cleared high-speed Acutus Medical's AcQMap High Resolution image and mapping system and the AcQMap 3-D Imaging and Mapping Catheter.  detects and displays both standard voltage-based and higher resolution dipole density (charge-source) maps. The system combines ultrasound anatomy construction with an ability to map the electrical-conduction of each heartbeat to identify complex arrhythmias across the entire atrial chamber. Following each ablation treatment, the heart can be re-mapped in seconds to continually visualize any changes from the prior mapping.

 

 

Feature | Atrial Fibrillation | November 07, 2017
November 7, 2017 — Here is an aggregated list of articles detailing the latest clinical data and new device technolog
UNC School of Medicine Receives $1.7 Million for Atrial Fibrillation Program Streamlining Patient Care
News | Atrial Fibrillation | October 23, 2017
October 23, 2017 — University of North Carolina (UNC) School of Medicine cardiologist Anil Gehi, M.D., will use a $1.
EMANATE Trial Shows Apixaban Lowers stroke in AF Patients Undergoing Cardioversion.
News | Atrial Fibrillation | September 01, 2017
September 1, 2017 — Apixaban lowers the risk of stroke compared to warfarin in anticoagulation-naïve patients with at
CASTLE-AF Study shows Catheter Ablation of Atrial Fibrillation is First-Line Treatment for Heart Failure Patients. Biotronic Ilivia 7 ICD.

The CASTLE-AF Study shows catheter alation of AF can be used effectively to treat heart failure in patients with an implanted ICD.

News | Atrial Fibrillation | September 01, 2017
September 1, 2017 — Final results from the CASTLE-AF study show a 38 percent reduction in the composite of all-cause
Overlay Init