Cerebral Protection During MitraClip Implantation

JACC: CARDIOVASCULAR INTERVENTIONS
VOL.
ª 2015 BY THE AMERICAN COLLEGE OF CARDIOLOGY FOUNDATION
-, NO. -, 2016
ISSN 1936-8798/$36.00
PUBLISHED BY ELSEVIER
http://dx.doi.org/10.1016/j.jcin.2015.09.039
Cerebral Protection During
MitraClip Implantation
Initial Experience at 2 Centers
Christian Frerker, MD,* Michael Schlüter, PHD,y Oscar D. Sanchez, MD,z Sebastian Reith, MD,x Maria E. Romero, MD,z
Elena Ladich, MD,z Jörg Schröder, MD,x Tobias Schmidt, MD,* Felix Kreidel, MD,* Michael Joner, MD,z
Renu Virmani, MD,z Karl-Heinz Kuck, MD*
ABSTRACT
OBJECTIVES This study sought to assess the feasibility and safety of using a filter-based cerebral protection system
(CPS) during MitraClip implantation and to report on the histopathologic analysis of the captured debris.
BACKGROUND Stroke is one of the serious adverse events associated with MitraClip therapy.
METHODS Between July 2014 and March 2015, 14 surgical high-risk patients (age 75 ! 7 years; 7 men; median logistic
EuroSCORE 21%) underwent MitraClip implantation employing cerebral protection with a dual embolic filter system. All
patients had severe mitral regurgitation of predominantly functional origin.
RESULTS All procedures were successfully completed for both CPS deployment/retrieval and MitraClip implantation.
A total of 28 filters (2 from each patient) were analyzed. Microscopically, debris was identified in all 14 patients. The most
common tissue types were acute thrombus and small fragments of foreign material, which were found in 12 patients
(85.7%) each. Organizing thrombus was present in 4 patients (28.6%), valve tissue and/or superficial atrial wall tissue in
9 patients (64.3%), and fragments of myocardium in 2 patients (14.3%). No transient ischemic attacks, strokes, or deaths
occurred peri-procedurally or during a median follow-up interval of 8.4 months.
CONCLUSIONS In this small study of patients undergoing MitraClip treatment with cerebral protection, embolic debris
potentially conducive to cerebrovascular events was found in all patients. Debris was composed most often of acute
thrombus, foreign material likely originating from the hydrophilic device coating, and valve/atrial wall tissue. Further
studies are warranted to assess the impact of cerebral protection on the incidence of cerebrovascular events after
MitraClip therapy. (J Am Coll Cardiol Intv 2016;-:-–-) © 2015 by the American College of Cardiology Foundation.
M
itral regurgitation (MR) is the second
implantation in 2008, several studies have attested
most common manifestation of valvular
to the safety and effectiveness of this new percuta-
heart disease in adults (1). Since the first
neous treatment option in patients with moderate-
MitraClip (Abbott Vascular, Santa Clara, California)
to-severe or severe MR (2–4). Current guidelines
From the *Department of Cardiology, Asklepios Klinik St. Georg, Hamburg, Germany; yAsklepios Proresearch, Hamburg, Germany;
zCVPath Institute, Inc., Gaithersburg, Maryland; and the xDepartment of Cardiology, University Hospital of the RWTH Aachen,
Aachen, Germany. Dr. Frerker reports that he has received lecture honoraria from Abbott Vascular, Inc., and Claret Medical, Inc. Dr.
Joner reports that he has received honoraria from OrbusNeich, Abbott Vascular, Boston Scientific, and Biotronik; and research grants
from OrbusNeich, Abbott Vascular, BioSensors International, SinoMedical, Terumo Corporation, CeloNova, W. L. Gore, Medtronic,
Microport, Boston Scientific, and Biotronik. Dr. Virmani reports that she has served as a consultant to 480 Biomedical, Abbott Vascular,
Medtronic, and W.L. Gore; has received honoraria from 480 Biomedical, Abbott Vascular, Boston Scientific, Cordis J&J, Lutonix Bard,
Medtronic, Merck, Terumo Corporation, W.L. Gore, CSI, Meril Life Sciences, and Spectranetics; and has received institutional grants/
research support from 480 Biomedical, Abbott Vascular, Atrium, BioSensors International, Biotronik, Boston Scientific, Cordis J&J,
GSK, Kona, Medtronic, MicroPort Medical, CeloNova, OrbusNeich Medical, ReCore, SINO Medical Technology, Terumo Corporation,
W.L. Gore, Spectranetics, CSI, Lutonix Bard, Surmodics, and Meril Life Sciences. Dr. Kuck reports that he has received consultant fees
and research grants from St. Jude Medical, Medtronic, and Edwards Lifesciences; and has received research grants from Abbott
Vascular, Inc. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
Manuscript received August 5, 2015; revised manuscript received September 14, 2015, accepted September 24, 2015.
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Cerebral Protection During MitraClip Implantation
ABBREVIATIONS
consider the MitraClip system to be a treat-
AND ACRONYMS
ment option for high-surgical-risk patients
ACT = activated clotting time
CPS = cerebral protection
(evidence class IIb) (5,6). Occurrence of a
stroke or a transient ischemic attack (TIA) is
one of the potential complications during
system
a MitraClip procedure. Incidences of 0.2% to
IQR = interquartile range
2.6% have been reported (2,3,7). Blazek et al.
MR = mitral regurgitation
MRI = magnetic resonance
imaging
Academic Research Consortium
TAVR = transcatheter aortic
valve replacement
T A B L E 1 Baseline Patient Characteristics (N ¼ 14)
Men
7 (50)
Age, yrs
75 ! 7
Body mass index, kg/m2
resulted in new ischemic cerebral lesions on
Cerebral embolic protection devices for
5,673 (1,603–12,160)
Left ventricle
End-systolic diameter, mm
studied.
21 (18–28)
NT-proBNP, pg/ml
End-diastolic diameter, mm
aging (MRI) in 23 (85.7%) of 27 patients
26 ! 4
Logistic EuroSCORE, %
(8) showed that the MitraClip procedure
diffusion-weighted magnetic resonance im-
MVARC = Mitral Valve
- 2016:-–-
61 ! 9
48 ! 15
Ejection fraction, %
37 ! 16
NYHA functional class
III
8 (57)
IV
6 (43)
Arterial hypertension
11/13 (85)
the prevention of cerebrovascular events
Hyperlipidemia
have been introduced for transcatheter aortic
Diabetes mellitus
5 (36)
valve replacement (TAVR) procedures (9). Van Mie-
COPD
5 (36)
ghem et al. (10) reported on the histopathologic
Pulmonary hypertension
7 (50)
TIA = transient ischemic attack
characteristics of debris captured and retrieved from
a filter-based cerebral embolic protection device in 30
(75%) of 40 patients undergoing TAVR. The present
study assessed the feasibility and safety of using a
9 (64)
Atrial fibrillation
8 (57)
Chronic renal insufficiency
7 (50)
Coronary artery disease
7 (50)
Previous cardiac surgery
2 (14)
Peripheral arterial disease
3 (21)
filter-based cerebral protection device during Mitra-
Prior stroke
2 (14)
Clip implantation and reports on the histopathologic
MR etiology
analysis of the debris captured.
METHODS
PATIENTS. Between July 2014 and March 2015, a total
of 14 surgical high-risk patients underwent a MitraClip procedure that employed cerebral protection
with the dual-filter Sentinel system (Claret Medical,
Santa Rosa, California) at two German sites (Hamburg
[n ¼ 10] and Aachen [n ¼ 4]). The Hamburg patients
were treated consecutively in 2 series of 6 and 4 pa-
tients; the Aachen patients were selected according to
the patient’s propensity for thromboembolic events
due to echocardiographically detected thrombus
material on pacemaker or defibrillator leads. Four
Degenerative
3 (21)
Functional
11 (79)
MR severity
Severe
14 (100)
Values are n (%), mean ! SD, or median (interquartile range).
COPD ¼ chronic obstructive pulmonary disease; EuroSCORE ¼ European System
for Cardiac Operative Risk Evaluation; MR ¼ mitral regurgitation; NT-proBNP ¼
N-terminal pro-brain natriuretic peptide; NYHA ¼ New York Heart Association.
of the anticoagulation during the MitraClip intervention; 5 patients had dual antiplatelet therapy with
aspirin and clopidogrel. Patients on dual antiplatelet
therapy received a 300-mg loading dose of clopidogrel after the MitraClip procedure. Written informed
consent was obtained from all patients.
patients (29%) had an internal cardiac defibrillator
CEREBRAL
(2 of them as a cardiac resynchronization therapy)
Cerebral Protection System (CPS) comprises 2 bag-
and 1 patient (7%) had a two-chamber pacemaker.
like embolic filters attached back-to-back to the tip
No patient had a porcelain aorta. Pertinent baseline
of a single 6-French compatible catheter, which is
patient characteristics are given in Table 1.
delivered from the right arm via radial or brachial
PROTECTION
DEVICE. The
Sentinel
All patients had severe MR of predominantly
artery access over a standard 0.014-inch coronary
functional origin. Left ventricular function was
guidewire (Figure 1). The filter bags are made of
impaired, with a mean ejection fraction of 37%, and
polyurethane film with 140-m m laser-drilled holes,
all patients presented with reduced physical capacity
and each filter is mounted on a self-expanding
(New York Heart Association functional class III or
nitinol wire loop. The system is advanced under
IV). A history of atrial fibrillation and prior stroke was
fluoroscopic guidance such that the larger proximal
present in 8 (57%) and 2 (14%) patients, respectively.
filter (loop diameter: 9 to 15 mm) is deployed in the
No patient was found to have a thrombus in the left
brachiocephalic trunk, and the smaller distal filter
atrial appendage or the left ventricle. Nine patients
(loop diameter: 6.5 to 10 mm), which is in an artic-
were on oral anticoagulation (phenprocoumon, n ¼ 4;
direct oral anticoagulants, n ¼ 5) without interruption
ulating sheath inside the proximal filter, is placed in
the left common carotid artery.
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F I G U R E 1 The Cerebral Protection Device Used in This Study
(A) Photograph of the Sentinel Cerebral Protection System (CPS) consisting of 2 filters for simultaneous protection of both the right side
(proximal filter) and the left side (distal filter) of the brain. (B) Schematic of the CPS in place, with the proximal filter deployed in the brachiocephalic trunk and the distal filter in the left common carotid artery.
MITRACLIP IMPLANTATION. A standardized anti-
examined grossly for visible debris, then cut open; all
coagulation regimen with heparin was initiated with a
contents were filtered through a 40-m m nylon cell
loading dose of 70 IU/kg aiming at an activated clot-
strainer (BD Falcon/Corning, Durham, North Car-
ting time (ACT) between 250 and 300 seconds. The
olina). The majority of particles detected were
bolus of heparin was given after the puncture of all
adherent to the filter, with only a small number of
peripheral vessels. Deployment of the cerebral pro-
immersed particles retrieved from the fixative. The
tection device was subsequently performed in all
cell-strainer disc was photographed to document
patients via right radial access—that is, before the
successful debris transfer, and measurements of the
transseptal puncture required for MitraClip implan-
retrieved debris were performed. The specimens were
tation. Left heart catheterization was not performed
dehydrated in a graded series of alcohols and
after placement of the CPS.
embedded in paraffin, and sections of 5 to 6 mm
The procedural details of percutaneous mitral
thickness were cut, with 2 sections mounted on each
valve repair using the MitraClip have been described
glass slide. The sections were stained with hematox-
before (2). All procedures were performed under
ylin and eosin and Movat’s pentachrome.
general anesthesia in a hybrid operating room. Procedural success was defined as discharge MR of
maximally moderate severity. Procedural details are
given in Table 2.
After MitraClip implantation, the embolic filters
T A B L E 2 Procedural Details and Outcome Parameters (N ¼ 14)
Hospitalization, days
ICU stay, days
were withdrawn into the catheter and removed from
Activated clotting time, s
the patient. Outside, the filters were cut and stored in
Contrast agent, ml
10% neutral buffered formalin solution and shipped
Tamponade
to the CVPath Institute (Gaithersburg, Maryland) for
Severe bleeding
analysis.
HISTOPATHOLOGIC
ASSESSMENT OF CAPTURED
DEBRIS. A total of 28 filters (2 from each patient)
were analyzed. The filters were photographed (Canon
EOS Rebel XSi; Canon U.S.A., Melville, New York),
7.4 ! 5.0
1 (1–2) [n ¼ 6]
289 ! 48
12.5 (10–20) [n ¼ 10]
0 (0)
0 (0)
Vascular complication
1 (7)
Stroke
0 (0)
TIA
0 (0)
Values are mean ! SD, median (interquartile range), or n (%).
ICU ¼ intensive care unit; TIA ¼ transient ischemic attack.
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The sections were evaluated for the presence of
thrombus, valve and atrial wall tissue, vascular
structures with or without atherosclerotic changes,
myocardial
fragments,
-, NO. -, 2016
calcification,
and
the clip delivery system from the left atrium—
amounted to 58 ! 31 min (range: 15 to 130 min).
There were no peri-procedural TIAs or strokes.
foreign
A single vascular complication occurred in a patient
material. Thrombus was classified as acute if it
in whom the supra-aortic arteries were insufficiently
showed platelets and fibrin with entrapped red blood
visualized by angiography; the patient experienced
cells and acute inflammatory cells, or as chronic if the
bleeding from a small thyroid artery, which was
thrombus showed the presence of spindle-shaped
treated conservatively by administration of prot-
cells with or without macrophages that lined the
amine at the end of the procedure. During a median
thrombus, infiltrated it, or had any organization with
follow-up period of 8.4 months (IQR: 3.5 to 10.3
matrix deposition interspersed between the fibrin/
months), no patient died or experienced out-of-
platelet thrombus. Two pathologists reviewed the
hospital TIA or stroke.
slides independently, and the final diagnosis was
based on unanimous agreement.
Histopathologic slides were scanned using a digital
slide scanner (Axion Scan.Z1, Carl Zeiss, Thornwood,
New York), and the morphometric analysis was performed using HALO digital image analysis software
(Version 1, Indica Labs, Corrales, New Mexico).
Quantitative measurements were performed on the
20 largest particles identified in each cross section.
The cumulative area of debris was quantitated in each
cross section using an internal algorithm for automated particle detection and was expressed as the
cumulative area per case. Minimum and maximum
diameters
of
individual
particles
were
also
determined.
HISTOPATHOLOGY. Microscopically,
debris
was
identified in all 14 patients. The morphometric analysis of a total of 515 sections (242 from proximal, 273
from distal filters) revealed a median cumulative
particle area per patient of 2.46 (IQR: 0.44 to 3.67)
mm 2 and a median maximum particle diameter of 295
(IQR: 104 to 509) m m; cumulative areas of debris
captured in proximal and distal filters were 1.35 (0.30
to 2.09) mm 2 and 1.07 (IQR: 0.13 to 2.21) mm 2,
respectively, with maximum diameters of 346 (IQR:
211 to 555) mm and 217 (IQR: 63 to 442) m m, respectively (p < 0.0001). The most common tissue types
were acute thrombus (Figure 2A) and small fragments
of
nonpolarizable
basophilic
foreign
material
(Figure 3) that was morphologically consistent with
STATISTICAL ANALYSIS. Continuous variables are
hydrogel, which were found in 12 patients (85.7%)
described as mean ! SD if normally distributed, or as
each. Organizing thrombus (Figure 2B) was present in
median (interquartile range [IQR]) if not. The Mann-
4 patients (28.6%), and 2 patients were devoid of any
Whitney U test was used to assess between-group
thrombus.
differences in maximum particle diameter, with p <
deposition, consistent with either valve tissue and/or
0.05 considered statistically significant. Categorical
superficial atrial wall tissue (Figure 4), was found in a
variables are described with absolute and relative
total of 9 patients (64.3%). Two patients (14.3%)
frequencies.
showed minute fragments of myocardium. Tissue
Fibroelastic
tissue
with
proteoglycan
particles exhibiting calcification were not observed in
RESULTS
any of the filters.
PROCEDURAL OUTCOMES. The mean ACT in the 14
cording to the number of clips implanted and the
procedures was 289 ! 48 seconds. All procedures were
study site are given in Tables 3 and 4, respectively. No
successfully completed for both CPS deployment/
difference in the distribution of debris type was
retrieval and MitraClip implantation; 6 patients were
apparent in either analysis. However, the maximum
discharged with no or trace residual MR, 5 had mild
particle diameters were statistically significantly
MR, and 3 patients were discharged with moderate
larger in patients treated with 2 clips (median 402 vs.
MR. A single clip was implanted in 7 patients (Hamburg
134 m m [1 clip], p < 0.0001) and in patients treated
Differentiations of histopathologic findings ac-
n ¼ 5, Aachen n ¼ 2); the other 7 patients received 2
clips each. The mean transmitral pressure gradient
after clip implantation was 3.3 ! 1.4 mm Hg (range: 1 to
6 mm Hg).
in Aachen (median 411 vs. 262 mm [Hamburg],
p < 0.0001).
The various combinations of types of debris as
found in the individual patients are shown in Figure 5.
The procedures lasted for a mean of 91 ! 43 min
The debris was composed of thrombus, valve/atrial
(range: 40 to 200 min), with a fluoroscopy time of
wall tissue, and foreign material in 8 patients (57%),
30 ! 16 min (range: 11 to 70 min). The total device time—
and of thrombus plus foreign material without any
the time from transseptal puncture to withdrawal of
valve/atrial wall tissue in 3 patients (21%). In 1 patient
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F I G U R E 2 Type of Thrombus
(A) Acute thrombus with platelet and fibrin (hematoxylin and eosin stained section). (B) Organizing thrombus with matrix deposition of
proteoglycan (yellow arrowheads) (Movat’s pentachrome stained section).
each the constituents of debris were thrombus and
DISCUSSION
myocardial fibers, foreign material and myocardial fibers, and valve/atrial wall tissue only.
The debris was contained in all 14 proximal and all
14 distal filters. The type of debris captured at the 2
filter locations is shown in Figure 6. Note the similarity of the distributions, with most filters at both
locations containing acute thrombus and foreign
material, followed by valve/atrial wall tissue. Two
filters
at
either
location
contained
organizing
MAIN FINDINGS. The main findings of this small
study of using a dual-filter CPS during MitraClip
implantation are as follows:
# Using the CPS during a MitraClip procedure is
feasible and safe.
# Debris was found in all patients, with larger parti-
cles identified in proximal filters, in patients
thrombus, and myocardial fibers were detected only
treated with 2 clips, and in patients at an increased
in 2 distal filters.
risk of thromboembolic events.
F I G U R E 3 Foreign Material
(A, B) Basophilic foreign material (yellow arrows) intermingled with acute fibrin-rich thrombus, rare neutrophils, and thrombocytes
(hematoxylin and eosin stained sections).
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F I G U R E 4 Valve Tissue
(A and C) Fibroelastic tissue with proteoglycan deposition corresponding to valve tissue and foreign material (blue arrows). (B) High-power
magnification of the boxed area in A. (D) High-power magnification of the boxed area in C. (A, B, C: hematoxylin and eosin stained section; D:
Movat’s pentachrome stained section).
# The most prevalent types of debris were acute
of new peri-procedural cerebral ischemic events (11).
thrombus and foreign material consistent with
In a recent consensus document, the Mitral Valve
hydrogel coating.
Academic Research Consortium (MVARC) stated that
CLINICAL
RELEVANCE. It
has been shown that
percutaneous interventional procedures bear the risk
T A B L E 3 Histopathologic Analysis According to Number of Clips
Implanted
stroke and TIA are “clinical endpoints to be collected
in all trials of mitral valve therapies” (12). The incidence of stroke or TIA after a MitraClip procedure of
up to 2.6% (7) justifies any attempt to prevent such
complications.
In this study, the Claret Sentinel device was
1 Clip
(n ¼ 7)
2 Clips
(n ¼ 7)
Thrombus
6 (86)
6 (86)
Acute
6 (86)
6 (86)
CPS. The overall procedure duration of 91 min
Organizing
2 (29)
2 (29)
compares favorably with procedure times reported
Foreign material
6 (86)
6 (86)
in the Pilot European Sentinel MitraClip Registry
Valve/atrial tissue
4 (57)
5 (71)
Myocardium
2 (29)
0 (0)
(138 min), the MitraClip post-approval ACCESS-EU
0.81 (0.36–2.06)
[n ¼ 7]
3.45 (2.80–6.80)
[n ¼ 7]
Type of debris in filters
Morphometry
Cumulative particle area,
mm2
Maximum particle diameter,
mm
134 (56–336)
[n ¼ 261]
Values are n (%) or median (interquartile range).
402 (275–589)
[n ¼ 254]
used for cerebral protection during MitraClip procedures. Except for one minor vascular complication, no complications occurred while using this
registry (100 min), and the German transcatheter
mitral
valve
interventions
(TRAMI)
registry
(103 min) (3,4,13).
In our series of patients without any periprocedural
cerebrovascular
events,
the
filters
captured debris in all patients. A recent diffusionweighted MRI study of patients after MitraClip
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T A B L E 4 Histopathologic Analysis According to Study Site
Hamburg
(n ¼ 10)
F I G U R E 6 Type of Captured Debris by Filter Location
Aachen
(n ¼ 4)
Type of debris in filters
Thrombus
9 (90)
3 (75)
Acute
9 (90)
3 (75)
3 (30)
1 (25)
Foreign material
Organizing
8 (80)
4 (100)
Valve/atrial tissue
8 (80)
1 (25)
Myocardium
1 (10)
1 (25)
2.24 (0.44–3.45)
[n ¼ 10]
5.00 (1.13–8.47)
[n ¼ 4]
Morphometry
Cumulative particle area,
mm2
Maximum particle diameter,
mm
262 (89–442)
[n ¼ 374]
411 (206–647)
[n ¼ 141]
Values are n (%) or median (interquartile range).
implantation without cerebral protection revealed an
86% incidence of newly acquired microembolic
cerebral lesions (8), suggesting a strong relationship
between embolic debris captured in filters during
MitraClip implantation with cerebral protection and
ischemic cerebral lesions detected by MRI after
MitraClip implantation without cerebral protection.
(A) Debris found in the 14 proximal filters protecting the
brachiocephalic trunk. The majority of filters (12 [86%] and 9
F I G U R E 5 Distribution of Debris Captured in 14 Patients
[64%], respectively) contained acute thrombus and foreign
material; valve/atrial wall tissue was present in 7 filters
(50%), and organizing thrombus was identified in 2 filters
(14%). (B) Debris found in the 14 distal filters protecting the
left common carotid artery. As in the proximal filters, the
majority of distal filters (11 [79%] and 10 [71%], respectively)
contained acute thrombus and foreign material; valve/atrial
wall tissue was present in 5 filters (36%), and organizing
thrombus and myocardial fibers were identified in 2 filters
(14%) each.
Although most of the MRI-detected embolic lesions
remained clinically silent, other studies have shown
that clinically silent cerebral lesions were associated
with neurocognitive impairment and the development of dementia (14,15).
Debris was captured by the cerebral protection system’s filters
in all patients. Pie chart segments represent numbers (and
POTENTIAL ORIGINS OF EMBOLI DURING TRANSCATHETER MITRAL VALVE REPAIR. Feld et al. (16)
percentages) of patients with different compositions of debris.
have shown that the Brockenbrough transseptal
Most often found was a combination of thrombus, valve/atrial
needle generates particles when advanced through
wall tissue, and foreign material (n ¼ 8; light blue segment)
the dilator and transseptal sheath. The particles in
and of thrombus and foreign material without valve/atrial wall
tissue (n ¼ 3; light brown segment). Thrombus plus myocar-
dium, foreign material plus myocardium, and valve/atrial wall
tissue only was found in 1 patient each.
that study were not examined further for the type of
material generated. In our study, foreign particles
found in the filters consisted of nonpolarizable
basophilic
material
that
was
morphologically
consistent with hydrogel. To date, no evidence has
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been found of foreign material arising from the
Both methodological additions to the study protocol
Sentinel filter itself and/or its coating. Even after we
as well as a comparison with a matched cohort of
manually scraped the surface of filters, no foreign
patients undergoing MitraClip implantation without
material was observed under high-magnification
cerebral protection would have been desirable.
microscopy.
Hydrophilic coating is frequently used on medical
CONCLUSIONS
devices for interventional procedures to decrease
friction between sheaths or catheters and vessel
In this study of 14 patients undergoing MitraClip
walls (17). Mehta et al. (18) identified hydrophilic
treatment using a CPS, embolic debris potentially
polymer
emboli in
conducive to cerebrovascular events was found in all
various
vascular
9 patients who underwent
different
patients. The debris was composed most often of
coated devices. Furthermore, multiple findings of
acute thrombus, foreign material likely originating
hydrophilic-coating
organs
from the hydrophilic device coating, and valve/atrial
have been described (19–21). For the MitraClip pro-
wall tissue. No peri- or post-procedural strokes or
cedure several catheters coated with hydrophilic
TIAs occurred. Further studies are warranted to
materials are used, such as the transseptal sheath
assess the impact of cerebral protection on the inci-
for transseptal puncture and the guide catheter for
dence of cerebrovascular events after MitraClip
the MitraClip system. However, it is unknown from
therapy.
interventions
material
in
using
different
which catheter the majority of foreign material
originated.
The MVARC stated that transcatheter mitral valve
therapies may predispose patients to the formation of
ACKNOWLEDGMENT The
authors
thank
Torie
Samuda, PA, for her assistance in the histopathologic
analyses.
thrombus (12). Acute thrombus could develop at the
REPRINT REQUESTS AND CORRESPONDENCE: Dr.
transseptal sheath as well as at the guiding catheter
Christian Frerker, Department of Cardiology, Asklepios
and the clip delivery system due to their thrombo-
Klinik St. Georg, Lohmühlenstr. 5, 20099 Hamburg, Ger-
genic nature. Maleki et al. (22) reported up to 9%
many. E-mail: [email protected].
thrombus formation on regular transseptal sheaths
despite adequate anticoagulation. In our study, anticoagulation was adequate (as reflected by a mean ACT
PERSPECTIVES
of 289 s throughout the procedures). In a cohort of 81
patients who underwent TAVR, thrombotic material
WHAT IS KNOWN? MitraClip implantation is a
was found in 74% of patients (23). However, in that
valid therapeutic option to relieve symptoms in
trial the ACT was suboptimal at a mean of 230 seconds
elderly patients with significant MR who are
(23).
deemed inoperable or at high surgical risk.
The origin of the valve and atrial wall tissue
Stroke has been observed, if rarely, in associa-
captured in 9 patients (64%) could be the dislodge-
tion with MitraClip therapy, and diffusion-
ment of such material during the transseptal punc-
weighted MRI studies have revealed a high
ture and the advancement of the MitraClip into the
incidence of new cerebral ischemic lesions after
left ventricle across the mitral valve. Furthermore,
the intervention.
during grasping of the mitral leaflets some valve tissue might be embolized.
Calcific debris was not found in any of the filters
analyzed in our study. This finding appears to be
consistent with the MRI study by Blazek et al. (8) who
reported no impact of mitral valve calcification on the
occurrence of embolic lesions.
STUDY
LIMITATIONS. The
number
of
patients
enrolled in this study was low. Most patients (11 of 14;
79%) had functional MR. Degenerative MR might be
associated with more valve-related debris. We made
no differentiation with respect to the type of MR. No
brain imaging or assessment of neurocognitive function before and after the intervention was performed.
WHAT IS NEW? The present study of a dual-filter
cerebral protection system employed during MitraClip
therapy has shown that embolic debris, composed
predominantly of acute thrombus and foreign material
likely originating from the hydrophilic device coating,
was released in all patients.
WHAT IS NEXT? Our findings warrant further
studies to assess the impact of cerebral protection
on the incidence of cerebrovascular events and
possibly identify patients in whom cerebral protection should be mandatory during MitraClip
implantation.
JACC: CARDIOVASCULAR INTERVENTIONS VOL.
Frerker et al.
-, NO. -, 2016
Cerebral Protection During MitraClip Implantation
- 2016:-–-
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KEY WORDS cerebral protection,
embolization, MitraClip, mitral regurgitation,
transcatheter mitral valve repair
9