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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3590_Библиотеки_им_академика_М_И_Перельмана
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254 5—VENTRICULAR SEPTAL INTERVENTIONS
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the uncertain risk of recurrent heart block. Patients who develop new right bundle branch
block or those with more advanced baseline conduction system disease require a temporary
permanent pacemaker for a minimum of 48 hours and may require more prolonged inpatient
monitoring beyond 72 hours to exclude development of heart block.
Outcomes
Over the first 6 weeks after ASA, myocardial remodeling and thinning of the basal septum results
in additional relief of outflow tract obstruction. Procedural success is achieved in approximately
85% of appropriately selected patients, especially in those with lower resting LVOT gradients and
lesser degrees of baseline septal hypertrophy. In a study following 177 patients after septal ablation at the Mayo Clinic for approximately 6 years, the survival free of all-cause mortality was
similar to that of the general population and matched patients who underwent surgical myectomy
for HOCM.
7
Data regarding long-term survival after ASA remain limited.
Summary and Take-Home Points
n
ASA is a safe and effective strategy to reduce LVOT obstruction and improve symptoms
in appropriately selected patients with HOCM.
n
Hemodynamic assessment and angiographic evaluation of septal anatomy are necessary
before performing septal ablation. Confirming the appropriate target vessel course is necessary for optimal procedural safety and efficacy.
n
Procedural success with ASA is achieved in a majority of patients with similar survival
compared with isolated surgical myectomy.
References
1. Maron BJ. Hypertrophic cardiomyopathy: A systematic review. JAMA. 2002;287(10):1308-1320.
2. Gersh BJ, Maron BJ, Bonow RO, et al. ACCF/AHA guideline for the diagnosis and treatment of hypertrophic cardiomyopathy. Circulation. 2011;124:e783-e831.
3. Spaziano M, Sawaya FJ, Lefevre T. Alcohol septal ablation for hypertrophic obstructive cardiomyopathy:
Indications, technical aspects, and clinical outcomes. J Invasive Cardiol. 2017;29(12):404-410.
4. Nishimura RA, Ommen SR. Hypertrophic cardiomyopathy. The search for obstruction. Circulation.
2006;114:2200-2202.
5. Sorajja P, Valeti U, Nishimura RA, et al. Outcome of alcohol septal ablation for obstructive hypertrophic
cardiomyopathy. Circulation. 2008;118(2):131-139.
6. El-Sabawi B, Nishimura RA, Barsness GW, Cha YM, Geske JB, Eleid MF. Temporal occurrence of
arrhythmic complications after alcohol septal ablation. Circ Cardiovasc Interv. 2020;13(2):e008540.
7. Sorajja P, Ommen SR, Holmes DR Jr, et al. Survival after alcohol septal ablation for obstructive hypertrophic cardiomyopathy. Circulation. 2012;126(20):2374-2380.
e1
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Abstract: Alcohol septal ablation is a safe and effective strategy to reduce left ventricular outflow
tract obstruction and improve symptoms in appropriately selected patients with obstructive hypertrophic cardiomyopathy. Invasive hemodynamic assessment and angiographic evaluation of
septal anatomy are important considerations before performing septal ablation. Confirming appropriate target vessel course is necessary for optimal procedural safety and efficacy. Procedural
success with septal ablation is achieved in a majority of patients with similar survival compared
with isolated surgical myectomy.
Keywords: Hypertrophic cardiomyopathy, outflow obstruction, alcohol septal ablation, myectomy, septal reduction
SECTION 6
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Left Atrial Interventions
255
CHAPTER 22
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Left Atrial Appendage Occlusion
Sidakpal S. Panaich David R. Holmes Jr.
Atrial fibrillation (AF) accounts for the majority of cardioembolic strokes, especially in elderly
individuals.
of AF patients have relative or absolute contraindications to anticoagulation.
high bleeding risk are also the patients at highest risk of stroke with AF.
1
Although anticoagulation reduces the risk of embolic stroke, a significant proportion
2–4
5
Patients with
Imaging studies have previously documented that .90% of embolic strokes in nonvalvular AF
originate from the left atrial appendage (LAA).
6
This might be secondary to specific anatomy of
pectinate muscles, as well as inflammation and fibrosis involving the LAA. This therefore makes
therapies targeted at LAA occlusion (LAAO) appealing. LAAO is currently covered by Centers
for Medicare & Medicaid Services (CMS) as an alternative for stroke prevention in patients with
an elevated stroke risk (CHADS2 2 or CHA2DS2-VaSc score 3) who have the appropriate
rationale for avoiding long-term oral anticoagulation after a shared decision-making process.
This chapter will primarily focus on the Watchman, which is currently the only Food and Drug
Administration (FDA)–approved endocardial LAAO device.
Left Atrial Appendage Occlusion Devices
The Watchman (Boston Scientific, Natick, MA) is the only percutaneous device (Fig. 22.1)
approved by the FDA for LAAO in United States.
age System for Embolic Protection in Patients with Atrial Fibrillation) trial
patients with nonvalvular AF and an additional risk factor for stroke (n 5 707) had similar rates
of stroke and cardiovascular death after Watchman compared with warfarin. The PREVAIL
(Prospective Randomized Evaluation of the Watchman LAA Closure Device in Patients with
Atrial Fibrillation Versus Long-Term Warfarin Therapy) trial also showed noninferiority to
warfarin.
10
The improving procedural success and safety have been replicated in real-world clinical practice with low rates of cardiac tamponade (≈1%), procedural strokes (,0.1%), and mortality
(,0.1%).
11
Some of the other percutaneous devices available in Europe include an Amplatzer Cardiac
Plug (ACP) or its newer iteration, the Amulet device (St. Jude Medical, Little Canada, MA), and
the WaveCrest (Coherex Medical, Salt Lake City, UT). The largest available literature on the
ACP (n 5 1047) demonstrated an annual stroke risk of 2.3% (59% lower than expected based on
patient risk scores).
12
The Amulet is reported to have a lower rate of periprocedural leaks than
the ACP and a lower risk of dislodgment. The Amplatzer Amulet LAA Occluder Investigational
Device Exemption (IDE) trial has been initiated in the United States to demonstrate its noninferiority to the Watchman.
13
Alternatively, epicardial approaches for LAAO may be considered in patients who cannot
tolerate any anticoagulation or do not have suitable LAA anatomy for endocardial occlusion.
The Lariat is a suturelike device that is inserted with a combination of endocardial and epicardial
8
The PROTECT AF (Left Atrial Append-
9
demonstrated that
7
256
22—LEFT ATRIAL APPENDAGE OCCLUSION 257
A
Single curve Double curve Anterior curve
B
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Fig. 22.1 (A) Watchman device with a 160-micron polyethylene terephthalate (PET) membrane. (B) Different
Watchman delivery sheaths. (Permission received from Boston Scientific.)
approaches and has high procedural success for LAA occlusion.14 There have been procedural
safety concerns with the Lariat due to possible LAA perforation and tamponade requiring
urgent cardiac surgery. The Aegis (Aegis Medical, Vancouver, Canada) allows for exclusively
epicardial LAAO and has thus far been studied primarily in canine models. Both open and
minimally invasive thoracoscopic surgical techniques have also been employed for LAAO.
Data on surgical techniques have been limited, with incomplete closure a concern with earlier
strategies. Newer devices such as the AtriCure AtriClip system promise to offer superior rates
of effective occlusion.
15
AHA Recommendations
The current European Society of Cardiology (ESC) and American Heart Association (AHA)/
American College of Cardiology guidelines suggest that surgical excision of the LAA may be
considered in patients undergoing cardiac surgery or thoracoscopic AF surgery (grade IIB).
LAA occlusion devices are not currently included in the AHA or ESC guidelines.
Patient Selection
The national coverage determination requires the following criteria:
n
CHADS2 score 2 or CHA2DS2-VASc score of 3
n
Documented evidence of a formal shared decision-making process between the patient
and a noninterventional physician using evidence-based decision-making tools on oral
anticoagulants
n
Suitable for short-term warfarin, but deemed unable to take long-term oral anticoagulation
These patients could be those with prior non-life-threatening bleeding events, those with high
HAS-BLED scores (typically .3), those with a history of coronary artery disease on dual antiplatelet therapy, and patients with end-stage renal disease (creatinine clearance ,15 to 30 mL/min).
Bleeding issues in such patients are of significant concern. The current recommendations for
16
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the Watchman device require at least 45 days of warfarin post–device implantation followed by
4.5 months of clopidogrel and lifelong aspirin (if the residual leak on follow-up transesophageal
echocardiogram [TEE] at 45 days is ,5 mm). Registry data have documented excellent safety and
efficacy of LAAO in these patients.
Patients with contraindications to even short-term anticoagulation were recently evaluated in
a nonrandomized ASA Plavix Feasibility Study With Watchman Left Atrial Appendage Closure
Technology (ASAP). The authors achieved a 64% relative risk reduction with the Watchman
device compared with historically expected rates of ischemic stroke in patients with a mean
CHADS
score of 2.8 when treated with antiplatelet therapy alone.
2
Preprocedural Planning
TEE is important to document absence of LAA thrombi and to determine the size and shape of
the LAA. The acceptable LAA ostium size should be .17 mm and ,31 mm for the Watchman
procedure. The LAA ostium should be measured in at least four TEE views: 0 degrees from the
left circumflex coronary artery to a point 2 cm from tip of the left upper pulmonary vein (LUPV)
limbus and 45, 90, and 135 degrees from the mitral valve (MV) annulus to a point 2 cm from the
tip of LUPV limbus. The LAA usable length should be measured next from the ostium to
the back wall along the neck axis. The usable LAA length should be equal to or greater than the
largest ostium diameter.
The LAA anatomy (Fig. 22.2) is highly variable, and its shape, number of lobes, presence of
pectinate muscles, etc. can be characterized on TEE. Although the shape of the LAA can be
described using terms such as “chicken wing” or “broccoli,” the only things that are really important are whether we have an adequate landing zone and whether the device will fully exclude the
LAA without extruding into the left atrium (LA).
AB
D
Fig. 22.2 Left atrial appendage anatomies. (A) Windsock. (B) Small broccoli (arrows pointing at different
lobes). (C) Anterior chicken wing (arrows pointing toward the direction of chicken wing). (D) Posterior chicken
wing (arrows pointing toward the direction of chicken wing).
C
22—LEFT ATRIAL APPENDAGE OCCLUSION 259
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Procedure
The Watchman is a semispherical nitinol frame partially coated with a polyethylene terephthalate
fabric cap (Fig. 22.1). The polyethylene terephthalate fabric serves as a 160-micron filter that faces
into the body of the LA and creates a permeable membrane to block thrombus embolization while
providing a scaffold over which endothelialization can occur. The base is anchored into the LAA
by 10 fixation barbs. The device is available in five different sizes: 21, 24, 27, 30, and 33 mm. The
Watchman Transseptal Access Sheath is available in double, single, and anterior curves
(14F outer diameter, 12F inner diameter, and a 75-cm working length).
The most important step of the LAAO procedure is a good transseptal location. In most
cases, this is mid-inferior and posterior on the interatrial septum guided by TEE (Fig. 22.3).
This is because the LAA is an anteriorly directed structure with its ostium perpendicular to
A
C
E
Fig. 22.3 Watchman procedure. (A) Measurements of the left atrial appendage preprocedure. (B) Transsep-
tal puncture in mid superior-inferior and mid anterior-posterior location (arrows). (C) Transesophageal-guided
advancement of the sheath (arrow) (with pigtail in front) into the anterior lobe of the left atrial appendage.
(D) Angiography of the left atrial appendage via pigtail. (E) Final deployed 30-mm Watchman device with 16%
compression (threaded insert marked by the arrow must be visible to ensure measurement is being made in
the widest cross-section). (F) Fluoroscopic image of the final deployed device.
B
D
F
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this axis. A mid-inferior and posterior puncture site allows the delivery sheath to be safely
advanced as deep as possible within the LAA for coaxial device deployment. An anterior
puncture will place the sheath out of the LAA plane, whereas a superior puncture could result
in noncoaxial sheath orientation or obstruction from the LUPV limbus/ “coumadin ridge.”
However, mid instead of posterior location might be more suitable for a LAA with a predominant posterior lobe for more direct vector orientation. Likewise, a prominent LUPV
limbus might prevent the device sheath from turning anteriorly into the LAA. In such cases,
a more mid rather than posterior transseptal puncture in this circumstance will allow easier
access to the LAA.
After the transseptal puncture, the transseptal sheath is advanced into the LA over a
0.0350 stiff guidewire that has been advanced into the LUPV. Alternatively, a Torayguide or
Baylis ProTrak (Baylis Medical, Montreal, Canada) guidewire can be looped in the LA. The
transseptal sheath can then be switched out over the guidewire for the Watchman sheath.
Three different Watchman sheaths are available: single curve (for superior LAA anatomies),
double curve (for superior and anterior anatomies), and anterior curve (for extremely anterior
anatomies) (see Fig. 22.1). After removing the dilator, the pigtail is advanced through
the Watchman sheath. The pigtail is then maneuvered with counterclockwise rotation into the
LAA, and the Watchman sheath is then slid over the pigtail catheter (with counterclockwise
rotation as necessary) into the LAA. It is important to always have a pigtail in front of
the sheath to avoid damage to the LAA wall. Once in the LAA, perform angiography in a
right anterior oblique (RAO) (20 to 30 degrees to visualize the mid-distal LAA) and caudal
(20 to 30 degrees to visualize the ostium) angulation, which allows visualization of the distal
lobes before advancing the sheath farther. The LAA should be fully evaluated with a TEE
sweep in all angles, especially 135 degrees, when advancing the sheath distally. It is also
important to measure mean left atrial pressure and attain adequate pressures (≈15 mmHg)
with fluid bolus if needed for accurate measurements.
The prepped Watchman delivery system, along with the compressed device, is advanced
through the sheath until both the distal marker bands of the sheath and delivery system are
aligned. The device is deployed by unsheathing slowly, without any forward movement, and
preferably with apnea for stable deployment. Once deployed, the device needs to be thoroughly
evaluated on TEE and fluoroscopy for “PASS” criteria:
1. Position (device at the ostium, not too distal, or shoulder protrusion ,40% to 50% of
device depth)
2. Anchor (test stability by retracting the deployment knob and letting go—the device should
return to the original position)
3. Size (device should be compressed 8% to 20% of original size on TEE)
4. Seal (residual flow around the device on TEE ,5 mm) prior to release
Distal positioning could leave some lobes uncovered, with a potential for thrombus formation
and embolization. If the device position is too distal, the device can be partially resheathed and
repositioned (Fig. 22.4). A proximal device, however, needs to be fully recaptured, and the procedure needs to be repeated using a new device through the existing sheath.
Some patients have anatomic reasons (esophageal varices, esophagectomy, etc.) that preclude
TEE. In this situation, intracardiac echocardiogram (ICE) guidance may be considered.
17
ICE
also offers the advantage of avoiding general anesthesia and intubation. Disadvantages include
limited 45-degree views and evaluation of LAA, which can sometimes be partly overcome by
imaging the LAA from the right ventricular outflow tract or advancing the ICE probe through
the transseptal puncture site into the LA.
17–19
Fig. 22.5 shows a case where ICE was used for a
patient with a history of esophagectomy with successful deployment of the Watchman device
without any complications.
22—LEFT ATRIAL APPENDAGE OCCLUSION 261
AB
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C
Fig. 22.4 Transesophageal echocardiography images demonstrating incomplete and complete coverage of all left atrial appendage lobes. (A) First deployment with incomplete coverage of a posterior lobe.
(B) Partial recapture and slightly proximal deployment with adequate coverage of all lobes. (C) Final deployed
Watchman device.
ABC
Fig. 22.5 Intracardiac echocardiography (ICE)–guided Watchman procedure. (A) Transseptal puncture
(arrow) guided by ICE. (B) Watchman device (thin, long arrow) being deployed under ICE guidance via device
sheath (thick, short arrow). (C) A deployed device with adequate compression (20 mm as measured resulting
in ≈25% compression for the device).
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Procedural Steps
Figs. 22.6 through 22.11 show the steps necessary when carrying out this procedure.
Procedural Complications
The acute procedural complications with the Watchman have declined with improved operator
experience. The risk of procedural ischemic stroke is ,0.5%, typically related to air embolism, or
thrombus in the LAA or on the equipment. Meticulous flushing and device preparation, adequate
procedural anticoagulation (operators can choose to fully anticoagulate or should at least give half
the weight-based heparin before transseptal puncture), and baseline imaging to exclude preexisting
thrombus can further reduce this risk.
Fig. 22.6 After transseptal puncture, the transseptal sheath is advanced into the LA over a
0.0350 over a stiff guidewire that has been advanced into the LUPV. Alternatively, a guidewire
can be looped in the LA. The transseptal sheath
can then be switched out over the guidewire for the
Watchman sheath.
Fig. 22.7 After removing the dilator, the pigtail
is advanced through the Watchman sheath. The
pigtail is then maneuvered with counterclockwise
rotation into the LAA, and the Watchman sheath is
then slid over the pigtail catheter (with counterclockwise rotation as necessary) into the LAA.
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