WATCHMAN Left Atrial Appendage System for Embolic Protection in Patients With Atrial Fibrillation - PROTECT-AF
Contribution To Literature:
The PROTECT-AF trial showed that left atrial appendage closure is noninferior to warfarin therapy alone in preventing cardiovascular death, stroke, or systemic embolism among patients with nonvalvular atrial fibrillation.
The goal of the trial was to evaluate left atrial appendage closure compared with warfarin in patients with nonvalvular atrial fibrillation.
Patients Screened: 4,998
Patients Enrolled: 707
Mean Follow Up: 16 months; intended follow-up to 5 years
Mean Patient Age: 72 years
Mean Ejection Fraction: 57%
- Patients with nonvalvular atrial fibrillation at least 18 years of age
- CHADS2 score of at least 1
- Contraindication to long-term warfarin therapy
- New York Heart Association class IV heart failure
- Presence or repair of an atrial septal defect
- Planned ablation procedure for atrial fibrillation
- Symptomatic carotid disease
- Left ventricular ejection fraction <30%
- Left atrial appendage thrombus
Primary efficacy endpoint defined as:
- Ischemic or hemorrhagic stroke, cardiovascular death, or systemic embolization
Primary safety endpoint defined as:
- Device embolization that required retrieval, pericardial effusion that required intervention, intracranial or gastrointestinal bleeding, or any bleeding that required transfusion
Patients with nonvalvular atrial fibrillation and at least one risk factor were randomized to left atrial appendage closure with the WATCHMAN device followed by discontinuation of warfarin after 45 days (n = 463) versus continued warfarin therapy (n = 244).
In the device arm, patients were treated with warfarin for 45 days, aspirin and clopidogrel until 6 months, then lifelong aspirin.
Patients in the warfarin arm received this study medication for the duration of the study.
Overall, 707 patients were randomized. Baseline characteristics were well matched between the groups. The mean age was 72 years, 30% were women, and the mean ejection fraction was 57%. Approximately two-thirds of the patients had a CHADS2 score of 1 or 2. In the device group, 87% of patients discontinued warfarin at 45 days.
The primary efficacy outcome, cardiovascular death, stroke, or systemic embolism, was 3.0 events per 100 patient-years in the device group versus 4.9 events per 100 patient-years in the control group (p for noninferiority >0.99). All strokes were 2.3 events per 100 patient-years versus 3.2 events per 100 patient-years (p = 0.99 for noninferiority), respectively. There was one hemorrhagic stroke in the device group versus six in the warfarin group (p > 0.99 for noninferiority). At a mean of 2.3 years, the primary efficacy outcome occurred in 3% per 100 patient-years in the device group versus 4.3% per 100 patient-years in the control group (p for noninferiority >0.99).
The primary composite safety outcome was 7.4 events per 100 patient-years in the device group versus 4.4 events per 100 patient-years in the control group. This was primarily related to complications (pericardial effusions) at the time of device implant. At a mean of 2.3 years, the primary safety outcome occurred in 5.5% per 100 patient-years in the device group versus 3.6% per 100 patient-years in the control group.
Pooled meta-analysis of PREVAIL and PROTECT-AF trials at 5 years: Cardiovascular death, stroke, or systemic embolism occurred in 2.8% of the device group versus 3.4% of the warfarin group (p = 0.27). Major bleeding or nonprocedure-related bleeding occurred in 1.7% of the device group versus 3.6% of the warfarin group (p = 0.0003).
Pooled analysis of PROTECT-AF, PREVAIL, CAP, and CAP2 trials: Device-related thrombus was present in 3.74%. Stroke or systemic embolism occurred in 7.46 per 100 patient-years among those with device-related thrombus versus 1.78 per 100 patient-years among those without device-related thrombus (p < 0.001). Predictors of device-related thrombus included history of transient ischemic attack/stroke, permanent atrial fibrillation, vascular disease, left atrial dilatation, and left ventricular systolic dysfunction.
Among patients with nonvalvular atrial fibrillation, the use of the WATCHMAN device for left atrial appendage ligation is feasible. This device demonstrated a noninferior rate of cardiovascular death, stroke, or systemic embolism, compared with warfarin alone, which was sustained to 5 years of follow-up. The rate of all strokes (ischemic or hemorrhagic) was noninferior between the groups, and there were significantly less hemorrhagic strokes in the device group. Adverse outcomes were higher in the device group due to a high occurrence of pericardial effusion. In a pooled analysis of four trials, device-related thrombus was detected in 3.74% and was a predictor of stroke or systemic embolism.
The procedural (and long-term) safety of this device will need to be balanced against the reduction in hemorrhagic strokes afforded from discontinuation of warfarin. It is also possible that this device may prove to reduce ischemic strokes; however, long-term follow-up will be needed to assess this.
Dukkipati SR, Kar S, Holmes DR, et al. Device-Related Thrombus After Left Atrial Appendage Closure: Incidence, Predictors, and Outcomes. Circulation 2018;May 11:[Epub ahead of print].
Reddy VK, Doshi SK, Kar S, et al., on behalf of the PREVAIL and PROTECT-AF Investigators. Left Atrial Appendage Closure: 5-Year Outcomes of the PREVAIL and PROTECT-AF Trials. J Am Coll Cardiol 2017;70:2964-75.
Editorial Comment: Saw J. Long-Term Results With Left Atrial Appendage Closure: Watching the Watchman. J Am Coll Cardiol 2017;70:2976-8.
Presented by Dr. Vivek Y. Reddy at the Transcatheter Cardiovascular Therapeutics meeting (TCT 2017), Denver, CO, November 2, 2017.
Reddy VY, Doshi SK, Siever H, et al. Percutaneous Left Atrial Appendage Closure for Stroke Prophylaxis in Patients with Atrial Fibrillation: 2.3 Year Follow-Up of the PROTECT AF Trial. Circulation 2013;Jan 16:[Epub ahead of print].
Holmes DR, Reddy VY, Turi ZG, et al. Percutaneous closure of the left atrial appendage versus warfarin therapy for prevention of stroke in patients with atrial fibrillation: a randomised non-inferiority trial. Lancet 2009;374:534-42.
Randomized Prospective Trial of Percutaneous Left Atrial Appendage Closure Versus Warfarin for Stroke Prevention in Atrial Fibrillation (PROTECT AF). Presented by Dr. David Holmes at ACC.09/i2, Orlando, FL, March 2009.
Keywords: Ligation, Stroke, Atrial Appendage, Warfarin, Atrial Fibrillation, Risk Factors, Embolism, Pericardial Effusion, TCT17, Transcatheter Cardiovascular Therapeutics
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