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Research
Articles
Cardiology Plus 2016, Vol 1. No10
3
RESEARCH ARTICLES
First clinical experience with new left atrial appendage closure
device - WATCHMAN FLX® system
Xin Xue² , Erich Duenninger1 , Manuela Muenzel1 , Adam Fazakas1, Nina Schneider1 , Jing Chang2 , Jiangtao Yu1*,
1 Helmut-G.-Walther Klinikum, Cardiology, Lichtenfels, Germany. 2 No.2 Hospital of Jilin
University, Cardiology, Changchun, PR China.
Abstract
BACKGROUND: Percutaneous left atrial appendage closure (LAAC) with WATCHMAN (WM)
has been recognized as a new interventional routine, but the development of device is continuing. The
WATCHMAN FLX® system (WMF) is a new equipment for LAAC which was used in patients since
Dec. 2015, but until now, there was a lack of clinical experience with the WMF device. We therefore
evaluated, in a selection of patients from a single hospital, the safety, feasibility, and effectiveness of the
WMF device on the early detection of LAAC.
RESULTS: LAAC was performed using WMF in 16 non-valvular atrial fibrillation (NVAF) patients
mostly contraindicated with long-term oral anticoagulants (OAC). Mean age at LAAC was 75±5, and
70.6% male. Hypertension, diabetes and stroke before operation were present in 87.5%, 25% and 18.8%
of patients, respectively. Mean CHADS2, CHA2DS-VASc and HASBLED scores were 3.0±1.1, 4.0±1.5
and 3.0±1.2, respectively. Success rate of device implantation was 100% with no severe major procedural
complications. Transesophageal echocardiography was performed in the first 6 weeks and 6 months after
LAAC, 100% patients were finished by 6 weeks follow-up. No device-related deaths were recorded.
Neither ischemic strokes nor transient ischemic attacks were observed. But 3 cases experienced device
dislocation. In those cases, the WMF devices slipped out of the left appendages, two at descending aorta
and one at ascending aorta. Fortunately, all the lost devices were found and successfully captured with
a Caesar grasping forceps system via A. femoralis (18F sheath). 12 patients have already accepted 6
months TEE, with one patient reporting thrombosis on the WMF surface.
CONCLUSIONS: LAAC with WM is a safe and effective therapy to prevent stroke in NVAF patients.
The WMF is upgrading novel and updated version of the WATCHMAN device, but should not be
considered as the penultimate device. Researchers will still need to accumulate clinical experience with
the WMF product, and device dislocation should be also be closely monitored.
Key Words:WatchmanFLX; Left Atrial Appendage Closure; Device Dislocation
* Response Author: Corresponding author: Director of Interventional
Cardiology Helmut-G.-Walter Klinikum
Prof-Arneth-Str. The Second Hospital
96215 Lichtenfels, Germany Tel: 0049-9571-129166
Email: [email protected]; [email protected]
Introduction
Atrial fibrillation (AF) is the most common cardiac arrhythmia,
affecting 3–5% of the population aged 65–75 years, and up to 8%
of those older than 80 years[1].The risk of stroke in AF patients
increases with age, AF accounts for up to 30% of strokes in
patients over 80 years old2. Oral anticoagulant treatment (OAC)
Cardiology Plus 2016, Vol 1. No 3
11
Figure1 WATCHMAN FLX® and Watchman
is recommended for stroke prevention in AF patients.
length, a longer distal fabric coverage, more strut frames, and
Percutaneous left atrial appendage closure (LAAC) with
more anchors (two rows). In addition, the WMF has a closed
WATCHMAN (WM) (Boston Scientific, Marlborough,
distal end thus allowing it to be partial recaptured and advanced
MA, USA) is an evolving therapy in AF. The results of the
into the LAA. It has a recessed metal screw on its proximal face
PROTECT-AF study demonstrated the superior effectiveness of
(Figure 1).
this approach in preventing thrombolytic complications of AF
We evaluated a selection of patients not receiving onsite cardiac
[3-5]
compared to OAC threapy
. However, mastery WM calls for a
steep learning curve, and therefore requires abundant operational
backup and within a single hospital, for the safety, feasibility,
and the early results of LAAC with WMF.
experience. For the beginner, unexpected complications often
occur in periintervention. In order to shorten the learning curve,
and reduce unexpected complications, a new device needed to
Methods
From December 2015 to February 2016, percutaneous LAA
be developed.
®
The WATCHMAN FLX system (WMF) (Boston Scientific,
closure (Watchman FLX® device) was performed in a total
Marlborough, MA, USA) is an upgraded device, compared to
of 16 patients, including one patient that underwent the same
the WM. It has a wider range of device size, a shorter device
procedure twice. The implantation procedure was performed
Xue et al LAAC - WATCHMAN FLX
12
by the same experienced investigators who followed clinically
In the case of a peri-device leak with flow >5 mm on follow-
accepted transesophageal echocardiography (TEE) guidelines.
up TEE, the initial anticoagulation regime (either warfarin or
This was a retrospective study designed to investigate the safety
aspirin/clopidogrel) was prolonged for another 6 weeks followed
and efficacy of LAAC with WMF. Patients with documented
by TEE.
chronic or paroxysmal non-valvular AF were all over 18 years
Endpoints
and an estimated life expectancy of at least 2 years .
The primary endpoint was successful implantation of the WMF
device. Secondary endpoints included complications during
Patient selection:
Inclusion criteria
device implantation and the occurrence of adverse events within
- sign the informed consent
determined by TEE, with indications of no or minimal leakage
- with AF at high risk of thromboembolic complications
(gap<5mm). Sealing was confirmed at 3 different time points:
- one of the following conditions were screened.
at the end of the implantation procedure, after 45 days and after
Bleeding complication while using OAC
6 months. Major adverse events were defined as: death, stroke,
Bleeding medical history leading to markedly elevated risk of
transient ischemic attack (TIA), systemic embolism, device
recurrence if use OAC
thrombosis and major bleeding requiring invasive treatment or
HAS-BLED score≥ 3
blood transfusion.
Difficult to manage the dose of warfarin to keep the stable INR
Statistical Analysis
Refuse OAC
Estimated frequencies of event occurrence are expressed as
Exclusion criteria
percentage or rate. Continuous variables are summarized as
-symptomatic valvular disease
mean ± standard deviation (SD).
the whole follow-up period. Successful sealing of the LAA was
-symptomatic carotid disease
-pregnancy
-intracardiac thrombus in the LAA visualized by TEE within 48
Results
h of the planned
LAAC was performed using WMF in 16 non-valvular atrial
implantation
fibrillation(NVAF) patients mostly with long-term oral
-indication other than AF for OAC therapy
anticoagulants (OAC) contraindications. Mean age was 75±5
Device Implantation
years old and 70.6% male. Hypertension, diabetes and stroke
The device implantation procedure is the same with WM which
[6]
before operation were present in 87.5%, 25% and 18.8%,
was described previously in detail . Patients were staying in
respectively. Mean CHADS2, CHA2DS-VASc and HASBLED
hospital overnight and discharged the next day after transthoracic
scores were 3.0±1.1, 4.0±15 and 3.0±1.2, respectively. (Table 1)
echocardiography examination in order to exclude pericardial
Success rate of device implantation was 100% and no severe
effusion. TEE follow-up was repeated at 45 days and 6 months,
major procedural complications.
to make sure there was no thrombus or leakage around the
During the procedure, no cases needed to change to different
device.
Medical Treatment
When there was no contraindication of warfarin, anticoagulation
therapy with warfarin was given for 45 days if there was no
thrombus or leakage around the device. This was confirmed by
TEE and then dual antiplatelet therapy (DAPT) with Aspirin
(100mg/day) and Clopidogrel (75mg/day) given for up to 6
months after implantation. This was then followed by oral
administration of 100mg/day Aspirin.
Patients with contraindication for warfarin were under the
following therapy: Enoxaparin sc. 0.01 mg/kg twice daily for 45
days. If no evidence of thrombus or leakage from TEE at 45-day
follow-up then one initiated a therapy of 100 mg aspirin plus 75
mg clopidogrel once daily until 6 months after implantation, and
finally followed by 100 mg aspirin.
Table 1 Baseline Demographic and Clinical Characteristics
of the Study Population
Characteristics
Age (years)
Male/Female
Atrial fibrillation type
paroxysmal
Persistent/Permanent
CHA2DS2-VASc
Congestive heart failure
Hypertension
diabetes mellitus(DM)
Stroke
CHADS2
HASBLED
Value
75±5 (Mean±SD)
11(68.8%)/5(31.2%)
5(31.2%)
11(68.8%)
4.0±1.5 (Mean±SD)
5(29.4%)
14(87.5%)
4(25.0%)
3(18.8%)
3.0±1.1 (Mean±SD)
3.0±1.2 (Mean±SD)
Cardiology Plus 2016, Vol 1. No 3
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Table 2 Characteristics of the procedure (n=17)
Procedure
N(%)
Major bleeding
Pericardial infusion
Other major bleeding
Thrombosis events
Stroke
Transient Ischemic Attack
Systemic Embolization
Device thrombosis
Device Dislocation
Size Change
Recapture
Gap(<5mm)
Gap(≥5mm)
failure
0
0
0
0
0
0
0
0(0.0%)
0(0.0%)
0(0.0%)
7(35.3%)
1(5.9%)
0(0.0%)
0(0.0%)
Discussion
Currently, OAC therapy is the traditional way to prevent stroke
in NVAF patients, however, more than half of patients do not
receive this therapy for various reasons[4]. The main caution for
prescription of OAC is the risk of cerebral and gastrointestinal
bleeding. In NVAF, over 90% thrombi formation was found
in the LAA[7], thus it is reasonable to seal the LAA to prevent
thrombus formation.
WM has been shown to be adequate in preventing stroke within
NVAF[8,9]. WMF is the upgraded product of WM. But until now,
we have few clinical experiences validating this latter device.
WM and WMF have the similar design, but WMF has some key
improvements according to the manufacturer's advertisement.
WMF is more flexible and has a flat top to prevent perforation of
size, 7 cases(35.3%) needed to recapture, Gap was discovered in
LAA wall during the release process, and two rows of hooks are
1 cases(5.9%).(Table 2)
placed to fix the device more firmly. Theoretically, WMF will be
Transesophagus echocardiography was performed in the first
easy and safe to be implanted, but in real world situations, we
6 weeks and 6 months after LAAC, 100% patients finished 6
have experienced some technical challenges.
weeks follow up. No device related death was recorded, and
For instance, in 3 of 17 cases we have experienced unexpected
neither ischemic stroke nor transient Ischemic attack were
dislocation in 6 weeks after intervention. The main operator of
observed. But 3 cases experienced device dislocation. The WMF
our center is skillful in the use of WM, so we think there is no
devices were out of left appendages: two from the descending
relationship with the operator skills. In fact we don’t understand
aorta, one from the ascending aorta. Fortunately, we found all
the real reason for dislocation. Maybe other factors should be
carefully considered.
Table 3 Complication during follow up
Follow-up Complications
N(%)
Thrombosis Event
0(0%)
Ischemic Stroke
0(0%)
Transient Ischemic Attack
0(0%)
Systemic Embolization
0
Device thrombosis
1(5.9%)
Device dislocation
3(17.6%)
Bleeding
0(0%)
Upper gastrointestinal
0(0%)
Thorax
0(0%)
Hemorrhagic stroke
0(0%)
Death
0(0%)
Cardiovascular Cause
0(0%)
Septic Shock
0(0%)
Other
0
We noticed that one of the three patients suffering from device
dislocation received another operation by implanting second
WMF smaller than the first one. It indicates that compression
ratio can’t be too large for the WMF. The WMF’s big
compression ratio affects not only LCX, but also the stability of
the device.
The WMF is short, so the demand of LAA’s depth is so strict
when implantation, but the device capacity center may moved to
the orifice of the LAA. ‘As a result, dislocation may happen.
WMF has two rows of hooks, it’s more than WM, but the hooks’
angle and length have many differences, thus the hooks may not
work well and fixed firmly.
What’s more, the flexibility of the WMF is better than WM, but
it needs a long time to release device to a final posture during
the procedure. We doubt that WMF may still have a mini gesture
of the lost devices, and successfully captured the device with
change after the tractive test and the mini change may cause the
Caesar grasping forceps system (COOK Medical, Winston-
dislocation.
Salem, Ireland) via A. femoralis (18F sheath). Two of the
In our research, one of the 17cases occurred device surface
dislocation patients, were served with a re-implanted Watchman
thrombosis, in fact, we speculate that it might be a result of
device instead, while the third patient was given another smaller
small possibility event. Further study with a larger of sample
WMF (from 27mm to 24mm). 12 patients have already accepted
size should be implemented to draw a conclusion.
6 months TEE, unfortunately there was 1 patient with thrombosis
According to our experience, the device characters including
on the WMF surface.(Table 3)
the length, flexibility and the hooks’ placed way may need some
Xue et al LAAC - WATCHMAN FLX
14
improvements.
update of the 2010 ESC Guidelines for the management of
Study Limitations
atrial fibrillation--developed with the special contribution
This study is retrospective and small scale with limited 17 cases,
of the European Heart Rhythm Association. Europace.
which is our main limitation.
2012;14(10):1385-1413.
6.
Conclusions
LAAC with WM is a safe and effective therapy to prevent stroke
atrial appendage closure device for atrial fibrillation. J Vis
Exp. 2012(60).
7.
in NVAF patients. The WMF is the new upgrading product of
Blackshear JL, Odell JA, et al. Appendage obliteration
to reduce stroke in cardiac surgical patients with atrial
the WATCHMAN device, but not the final device. It still needs
accumulating clinical experience with WMF, and the device
Möbius-Winkler S, Sandri M, et al. The WATCHMAN left
fibrillation. Ann Thorac Surg. 1996;61(2):755-759.
8.
dislocation should be also alerted.
Yu J, Guan S, Huemmer H, et al. Percutaneous left atrial
appendage closure in patients with non-valvular atrial
fibrillation with Watchman® left atrial appendage device:
single center experience and results up to three years
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Declaration of interest
van Walraven C, Jennings A, et al. Effect of study setting
Dr. Yu has research donation or travel expense reimbursement of
on anticoagulation control: a systematic review and
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