Percutaneous left atrial appendage

Left atrial appendage occlusion for
stroke prevention in atrial fibrillation
LAA OCCLUSION FOR STROKE
PREVENTION IN AF

INTRODUCTION
 AF
 0.4% to 1% of the general population.
 most common sustained cardiac arrhythmia
 3–5% of the population aged 65–75 years
 increasing to >8% of those older than 80 years.
 risk of ischaemic stroke in non-valvular
AF(NVAF) is 3–5%/year, which is a fivefold
increase compared with the unaffected population
PREVENTION IN AF

AF
• 15–20% of strokes in the general population and
for up to 30% in patients over the age of 80
years.
• prevention of stroke-OAC is the standard
treatment in patients with AF with a
CHA(2)DS2-(VASc) stroke risk score ≥1.
• LAA occlusion -AF with a high stroke risk and
contraindications for OAC.
PREVENTION IN AF

RISK SCORES
PREVENTION IN AF

Rationale for LAA occlusion
 60% of atrial thrombi in valvular AF – LAA
 in NVAF >90% of thrombi were located in the
LAA.
 LAA found to be the dominant source of
thrombus in patients with NVAF
 reduces the risk of AF-induced stroke in such a
range that it outweighs the possible risk on
procedural complications.
PREVENTION IN AF

INDICATION
 ESC (2012) -LAA closure may be considered in
patients with a high stroke risk and
contraindications for long-term OAC
administration
(Class IIb, level of evidence B)
PREVENTION IN AF

Patient selection
 All patients with NVAF with increased stroke risk
and contraindication(s) to OAC
 Patients with NVAF with a high stroke (CHADS2)
and bleeding (HAS-BLED) risk score
 Higher the stroke risk of the individual patient,
the larger the ‘Net clinical benefit’ of LAA closure
in comparison to OAC therapy
PREVENTION IN AF

 Patients with a high risk for thromboembolism—
for example, left ventricular (LV) dysfunction or
prior stroke—have also been reported to be at a
higher risk of thrombus formation in the LA cavity
(and not in the LAA) and device thrombosis.
 combined risk of stroke, thromboembolism,
bleeding and other adverse events - best way to
select patients most suitable for LAA closure.
PREVENTION IN AF

Indications for percutaneous LAA
closure
 Patients with AF at high stroke risk with high risk
(or recurrence) of bleeding under (N)OAC due to
 Uncontrolled, severe hypertension
 Coagulopathies—low platelet counts, MDS
 Inherited bleeding disorder— vWD,
haemophilia
 Severe hepatic or renal dysfunction—eg,
alcoholic liver disease,cirrhosis
PREVENTION IN AF

 Vascular disease or malformations— eg,
intestinal angiodysplasia,Osler-Weber-Rendu
disease,previous intracerebral
haemorrhage,cerebral microbleeds (∼amyloid
angiopathy), retinal vasculopathy
 Insufficiently treatable GI disease with bleeding—
eg, neoplastic disease, intestinal angiodysplasia
 Recurrent nephrolithiasis
 High probability of frequent and/or severe
traumas—eg, epilepsy,in the elderly
PREVENTION IN AF

 Ischaemic stroke despite well controlled OAC
therapy
 High probability of therapeutic non-compliance to
(N)OAC
 Intolerance to (N)OAC drugs--GI intolerance,
severe liver/
kidney dysfunction, drug interactions
 Other contraindications for (N)OAC
PREVENTION IN AF

Contraindications for percutaneous
LAA closure
 Low risk for stroke CHA(2)DS2-(VASc)=0
 VHD(eg, MS)
 Other indications for long-term or lifelong
OAC—mechanical prosthetic valve, PTE and
DVT ,thrombi in the LA or LV
 Contraindications for transseptal LA thrombus
or tumour, active infection, uncooperative
patient,( presence of ASD/PFO closure
device) a thrombus in the LAA
PREVENTION IN AF

LAA anatomy
• The LAA derives from the primordial left atrium
(LA), which is formed mainly by the adsorption of
the primordial
pulmonary veins and their branches.
• LAA has a highly variable anatomical structure ,it
is important to correctly evaluate the LAA
anatomy
• best way -MDCT and/or angiography
• LAA orifice and neck can also readily be
examined by TEE
PREVENTION IN AF

 LAA extends between the anterior and the lateral
walls of the LA, and its tip is directed
anterosuperiorly, overlapping
the left border of RVOT or PT and the main stem
of LM or LCX.
 Veinot et al. defined lobes as protrusions from
the main body with the tail portion also
representing a lobe, whereas bends in the tail do
not constitute more lobes.
 2 lobes were most common(54%), followed by 3
lobes (23%), 1 lobe (20%), and 4 lobes (3%),
PREVENTION IN AF

 An increased number of lobes was associated
with the presence of a thrombus
 muscle bundles in the LAA do not ramify like the
teeth of a comb but instead, they have a feather-
type-palm-leaf arrangement.
PREVENTION IN AF

LAA classification
 (1) chicken wing: an LAA with an obvious bend in
the proximal part of the dominant lobe;
 (2) windsock: an LAA with a main lobe of
sufficient length (>4 cm) as the primary structure;
 (3) cauliflower: an LAA that has limited overall
length (<4 cm) without any forked lobes;
 (4) cactus: a dominant central lobe with
secondary lobes extending from the central lobe.
PREVENTION IN AF

PREVENTION IN AF

 ‘chicken wing’ -lower stroke risk , procedural
challenge and a modified implantation technique
may be preferred.
 ‘cauliflower’ morphology /smaller LAA orifice,
larger neck dimension and extensive LAA
trabeculation -higher stroke risk
PREVENTION IN AF

 understanding the different configurations of the
LAA ostium and neck is vital, as the occluder is
anchored at the neck and must cover the ostium.
 Three different morphologies of the LAA ostium
and neck: (1) Horn shaped: LAA ostium wider
than the neck,
(2) Parallel tube: an ostium and neck that are
similar in dimension and
(3) Angel wing: a neck with larger dimensions
PREVENTION IN AF

LAA FUNCTION AND THROMBUS
FORMATION
 Normal contraction of the LAA during SR and
adequate blood flow within the LAA lower the risk
for thrombi
 Thrombus formation - reduced contractility and
stasis ensue.
 AF -decrease in LAA contractility and function,
manifest as a decrease in Doppler velocities and
dilation of the LAA.
 Significant LV dysfunction and elevated LV EDP
-LAA thrombus formation in the absence of AF.
PREVENTION IN AF

NONINVASIVE IMAGING OF THE
LAA
FOR RISK ASSESSMENT
 TEE - LAA morphology and flow patterns within it.
 sensitivity and specificity of TEE for detection of
LAA thrombi - 92% and 98%
 functional assessment of the LAA using Doppler
echocardiography is routinely used.
PREVENTION IN AF

 In SR, the LAA is usually a highly contractile
muscular sac that obliterates its apex during atrial
systole and can be seen by TEE and confirmed
by pulsed and color flow Doppler.
 AA velocity and color flow in SR are concordant
with LAA reduction in size, reflecting true
contraction, whereas in AF this normal pattern is
usually replaced by a chaotic one of varying
velocities.
 Flow in the appendage -sampling done at the
site where maximal flow velocities are obtained
(usually in the proximal third of the appendage)LAA OCCLUSION FOR STROKE
PREVENTION IN AF

LAA flow pattern. A.
sinus rhythm
quadriphasic wave pattern
PREVENTION IN AF

B)PWD-tracing of LAA flow in sinus rhythm.
C) PWD-tracing of LAA flow in atrial fibrillation.
PREVENTION IN AF

 normal subjects-, LAA contraction is
quadriphasic with velocities ranging from 50 to
83 cm/s with filling velocities ranging from 46 to
60 cm/s.
 Decreased velocities in SR - elevated LA
pressure.
 AF- flow signals are highly variable with a
sawtooth pattern or the absence of identifiable
flow waves although they tend to have lower
velocities during ventricular systole (when the
LAA contracts against a closed mitral valve) with
increasing heart rate reducing the peak flow
velocity
PREVENTION IN AF

 Velocities
 highest in SR
 intermediate -paroxysmal AF and atrial flutter
 lowest -chronic AF.
 Velocities <40 cm/s -higher risk of stroke and the
presence of SEC ,
 velocities of <20 cm/s -thrombus within the LAA
and a higher incidence of thromboembolic events.
PREVENTION IN AF

Imaging of the LAA
(1) preprocedural TEE is used to screen suitable
candidates and to define LAA morphology and
dimensions;
(2) periprocedural -guiding delivery and
deployment of the device and for assessing
procedural complications;
(3) postprocedural -surveillance
and monitoring of long-term outcome
PREVENTION IN AF

TEE IMAGES OF LAA
PREVENTION IN AF

 LAA ostium, LAA neck width (orifice width or
‘landing zone’) and LAA depth should be
measured.
 The LAA neck width - plane from the LCx
coronary artery to a point 10 mm distal to the
limbus (white arrow) of the left superior
pulmonary vein (LSPV).
 risk of undersizing is device embolization
 risk of oversizing is compression on the LCx
and/or LSPV, as well as LAA perforation and
device embolisation
PREVENTION IN AF

 These various LAA configurations can influence
device/size selection and implantation success.
 The risk of device dislodgement -highest in horn-
shaped configuration of the LAA.
 Choosing a device large enough to cover the
ostium and yet maintain the optimal degree of
oversizing in the ‘landing zone’ to secure
anchorage can be a challenge
 Amount of trabeculation of the ‘landing zone’and
the depth of the LAA (especially important if using
the WATCHMAN device) need to be assessed to
ensure that the optimal device is chosen.
PREVENTION IN AF

 Important aspects to assess are the number,
shape and location of the lobes.
 large LAA neck width (>26 mm) or complicated
LAA anatomy-preprocedural imaging with CT/MRI
should be considered.
 LAA size is dependent on the LA pressure
(‘loading status’) as well as on the presence of
sinus rhythm or AF.
PREVENTION IN AF

LAA CLOSURE DEVICES
PREVENTION IN AF

PLAATO device
PREVENTION IN AF

PLAATO device
 PLAATO (Percutaneous Left Atrial Appendage
Transcatheter Occlusion) system
 first device specifically developed
 self-expanding nitinol cage with three anchors on
each strut and was covered with a nonthrombogenic
PTFE membrane.
 anchoring barbs provided the stability;
 PTFE membrane prevented mobilisation of thrombi
from the LAA and promoted healing.
 device diameter ranged between 15 and 32 mm
 normally selected 20–40% larger than the diameter of
the LAA ostium.
 no longer available for clinical use after withdrawal
from the market in 2006
PREVENTION IN AF

RAO View
PREVENTION IN AF

Watchman device
 approved by FDA in 2015 for nonvalvular AF
patients at risk for stroke without contraindication
to anticoagulation.
 Watchman Left Atrial Appendage System for
Embolic Protection in Patients With Atrial
Fibrillation (PROTECT-AF) trial -trial to examine
the efficacy of the Watchman device.
 self-expanding nitinol frame covered with a
porous filtering PET (polyethylene terephthalate )
membrane.
PREVENTION IN AF

 stability of the device is secured by fixation barbs
located circumferentially.
 PET membrane acts as a filter preventing the
outflow of the thrombi and promotes
endothelialisation.
 five different sizes ranging from 21 to 33 mm
 selected 10–20% larger than LAA diameter to
ensure stable device positioning.
 can be recaptured and withdrawn in case of
suboptimal fixation.
PREVENTION IN AF

WATCHMAN Device
PREVENTION IN AF

TEE Image LA Angiogram
PREVENTION IN AF

ACP Device
 lobe and a disk connected by a short, flexible waist, both
the lobe and disk are constructed from a nitinol mesh
covered with a polyester patch.
 The lobe is implanted within the neck of the LAA (the so-
called
‘landing zone’), and achieves device stabilization and
retention by means of a number of stabilization wires.
 delivery system is 9-13Fr depending on the size of the
device.
 lobe size ranges from 16-30 mm and the disk from 20–36
mm;
 size of the lobe should be chosen 3 to 5 mm larger than
the diameter of the ‘landing zone’.
 not designed to fill the LAA but to seal its ostium by means
of the larger disk.
 better choice when challenged with a more complex
PREVENTION IN AF

AMPLATZER CARDIAC PLUG
PREVENTION IN AF

LA Angiogram TEE Image
PREVENTION IN AF

Minimally invasive external
occlusion of LAA
Lariat system
AtriClip
PREVENTION IN AF

Lariat system
 3 components: a balloon catheter, magnet-tipped
guidewires, and an epicardially placed 12-F
suture delivery device.
 requires both epicardial and endocardial
approaches to occlude the LAA.
 Using a transseptal approach, the LA is entered,
and the
endocardial magnet-tipped guidewire is placed
in the apex of the LAA, over which the balloon
catheter is advanced to the neck of the LAA.
 A second magnetic wire is advanced through the
pericardial space to the epicardial surfaceLAA OCCLUSION FOR STROKE
PREVENTION IN AF

 When the 2 magnetic wires are opposed, a suture can
be guided over the rail formed by the 2 magnet-tipped
guidewires and positioned basal to the balloon
inflated in the neck of the LAA.
 Once adequate placement is confirmed with imaging,
the epicardial suture can be secured and the LAA
ligated.
 As the Lariat system leaves no hardware inside the
LA after
the LAA is occluded, there is no clear need for
postprocedure anticoagulation.
 The Lariat device received 510(k) clearance by the
FDA as a suture for tissue approximation, but not
specifically for LAA exclusion or stroke prevention
PREVENTION IN AF

LARIAT PROCEDURE
PREVENTION IN AF

AtriClip
 self-closing external rectangular LAA occluder.
 4 sizes, from 35 mm to 50 mm, in 5-mm
increments.
 2 nitinol springs joined with 2 titanium members
covered with Dacron polyester fabric.
 parallel compression planes symmetrically exert a
pressure of 2 to 8 psi over the entire contact area,
effectively forming a surgically implanted clamp
across the base of the LAA.
 applied epicardially via a median sternotomy or
video-assisted thorascopic surgical approach .
 FDA 510(k) approval of the device
 indicated for LAA occlusion under direct
visualization, in conjunction with other open
cardiac surgical procedures..
PREVENTION IN AF

ATRICLIP
PREVENTION IN AF

NEW LAA OCCLUSION DEVICES
IN
DEVELOPMENT
 Sierra Ligation System -epicardial
electrocardiogram-guided LAA capture and
ligation system. =canine models and a feasibility
study is on the way .
 Lambre =self-expanding nitinol device with
high success rates in canines.
 WaveCrest and Occlutech
PREVENTION IN AF

Coherex WaveCrest LAA occlusion
system
 latest development in
 nitinol frame with retractable coils and anchors to
enable optimal device positioning.
 multi-composite membrane including a PTFE
membrane on the LA side of the device, and a
foam substrate on the LA-opposing surface to
minimize residual leaks.
 WAVECREST I clinical trial was completed - CE
Mark approval was obtained in September 2013.
PREVENTION IN AF

Coherex WaveCrest LAA
occlusion
PREVENTION IN AF

Device implantation
 general anaesthesia
 TEE and fluoroscopic guidance
 Antibiotic prophylaxis =prior to the procedure.
 Vascular access through a femoral vein
 delivery system is introduced by transseptal
puncture using a standard transseptal needle
and sheath.
 the puncture site is preferably inferior and
posterior in the fossa
PREVENTION IN AF

.
 After the puncture,a bolus of unfractionated
heparin to achieve ACT >250 s.
 TEE (or intracardiac echocardiography (ICE)) and
contrast angiography of the LAA (right anterior
oblique 30°/cranial 30°) =LAA dimensions(ostium,
neck width, depth)—based on these
measurements, the size of the device is chosen
 device is deployed by withdrawing the sheath
over the device (to reduce the risk of perforation).
PREVENTION IN AF

.
 Once in position, the device stability is confirmed
by a ‘tug test’, and complete sealing is verified by
colour Doppler imaging.
 Finally, the device is released from the delivery
cable and possible complications such as
pericardial effusion are ruled out.
 To avoid embolism of the Watchman Device,
there are four release criteria that should be
evaluated before release: Position, Anchor, Size
and Seal (PASS).
 Position: To confirm that the device is properly
positioned, ensure that the plane of maximum
diameter of the device is at or just distal to the
PREVENTION IN AF

PREVENTION IN AF
 Anchor: To confirm the device is anchored in
place, withdraw the access sheath/delivery
catheter assembly 1-2 cm from the face of the
device. After injecting a small puff of contrast
gently retract and push the deployment knob to
see the combined movement of the device and
the LAA tissue.
 Size: To confirm the correct device size, measure
the plane of the maximum diameter of the device
using TEE in the 4 standard views 0, 45, 90, and
135 degrees, ensuring the threaded insert is
visible. The device size should be 80%-92% of
the nominal diameter.
 Seal: Using colour Doppler, ensure that all of the
lobes are distal of the device and are sealed. If
there is a gap visible between the wall of LAA and
the device with more than 3 mm, the device

Postprocedural considerations
 chest X-ray and TTE before discharge -device
embolisation and pericardial effusion.
 After 45 days-control TEE to verify complete
sealing of the LAA and the absence of a
thrombus.
 OAC was given for 45 days and patients
discontinued OAC if the 45-day TEE control
showed either complete closure of the LAA or if
the jet width of the residual peridevice flow was
<5 mm.
 After stopping OAC therapy, patients were given
DAPT with ASA and clopidogrel until completion
of the 6-month TEE control, after which ASA
monotherapy was continued indefinitely
PREVENTION IN AF

 WATCHMAN implantation can be safely
performed without OAC transition and that DAPT
prescribed for 6 months followed by ASA alone
 ACP device- OAC has been avoided and DAPT
from 1 to 6 months after implantation, followed
by ASA alone.
 Incidence of device thrombosis - 4% to 17%.
 incidence of thrombus formation is more
frequent in the first few weeks/months and
significantly declines with complete
endothelisation of the occluder surface
PREVENTION IN AF

 device thrombosis- subcutaneous heparin for 2
weeks followed by TEE, and DAPT therapy is
extended for a longer period.
 Risk for thrombus formation on the device -high
platelet count, high stroke risk score and low LV
EF.
 After percutaneous LAA exclusion with the Lariat
snare device in which no intracavitary device is
left behind, thrombus formation can occur at the
LAA ostium , so postprocedural antiplatelet
therapy is also indicated for this device
PREVENTION IN AF

Complications of percutaneous
LAA
closure
 Cardiac perforation
 Pericardial effusion with tamponade
 Device embolisation
 Device thrombosis
 Stroke/TIA—thromboembolism, air embolism
 Vascular complications
 haematoma, bleeding, AV fistula
PREVENTION IN AF

 Peridevice leaks
 (1) severe—multiple jets or free flow;
 (2) major—jet width >3 mm;
 (3) moderate—jet width of 1–3 mm and
 (4) minor—jet width <1 mm.
 Major residual leaks -62%,32% and 10% of the
patients after PLAATO, WATCHMAN and ACP
PREVENTION IN AF

 lower rate of residual leak -ACP implantation
(double-disk structure of the ACP, which may
contribute to a better sealing of the LAA orifice)
 presence of residual peridevice leaks has never
been associated with cardioembolic events.
 when detecting major residual peridevice leaks,
OAC therapy is continued or restarted for several
weeks /months until the next control TEE in the
hope of a complete closure or jet width <3 mm.
PREVENTION IN AF

PROTECT AF trial
 Only prospective, RCT
 707 patients with NVAF -2:1 ratio to either
percutaneous LAA occlusion with the WATCHMAN
device or to warfarin therapy.
 paroxysmal,persistent or permanent NVAF were
eligible for enrolment if they had a CHADS2 risk score
≥1
 confirmed the non-inferiority of WATCHMAN LAA
occlusion compared with OAC therapy regarding
the
primary efficacy endpoint—a composite of stroke,
systemic
embolism and cardiovascular death (RR=0.62,95% CI
0.35 to 1.25)
 The probability of non-inferiority of the intervention
was >99.9%.LAA OCCLUSION FOR STROKE
PREVENTION IN AF

 4-year follow-up results from the PROTECT AF trial
were presented
 primary efficacy endpoint -40% relative risk reduction
in primary efficacy in the WATCHMAN group.
 Cardiovascular death occurred in 1.0% of the device
group vs 2.4% of the warfarin group (p<0.05)
 rate of haemorrhagic stroke was 0.2% in the device
group vs 1% in the warfarin group (p<0.05).
 long-term follow-up data -additional support
PREVENTION IN AF

PREVAIL Study
 n=269, WATCHMAN
 large multicentre study
 ACP device (n=969)
 improved procedural safety—complication rates
within
7 days were 4.1%, 4.4% and 4.1%, respectively,
as compared with >7% in the initial PROTECT
AF trial (2009)
 lower rates of periprocedural major adverse
events can be ascribed to a better understanding
of the procedure and an operator learning curve
effect.
PREVENTION IN AF

5-Year Outcomes
After Left Atrial Appendage
Closure
From the PREVAIL and PROTECT
AF Trials
PREVENTION IN AF

• PROTECT AF (WATCHMAN Left Atrial
Appendage System for Embolic Protection in
Patients With Atrial Fibrillation) -Watchman device
was equivalent to warfarin for preventing stroke in
atrial fibrillation, but had a high rate of
complications.
• PREVAIL (Evaluation of the WATCHMAN LAA
Closure Device in Patients with Atrial Fibrillation
Versus Long Term Warfarin Therapy), -
complication rate was low.
PREVENTION IN AF

• PREVAIL and PROTECT AF are prospective
randomized clinical trials with patients
randomized 2:1 to LAAC or
warfarin; together, they enrolled 1,114 patients
for 4,343 patient-years.
• These 5-year outcomes of the PREVAIL trial,
combined with the 5-year outcomes of the
PROTECT AF trial-Watchman provides stroke
prevention in NVAF comparable to warfarin,with
additional reductions in major bleeding,
particularly hemorrhagic stroke, and mortality.
PREVENTION IN AF

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