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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3597_Библиотеки_им_академика_М_И_Перельмана
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Figure 7-3 The trans-septal arrow is oriented approximately 45 degrees
posteriorly. FII, Frontal image intensifier; LII, lateral image intensifier. (From
Weiner RI, Maranhao V: Development and application of transseptal left
heart catheterization. Cathet Cardiovasc Diagn 15:112–120, 1988.)
Special Techniques
FII
Anterior
45°
LII
Posterior
Superior
atrial
boundary
Aortic root
Posterior
atrial
boundary
1-3 cm
X
Inferior
atrial boundary
Figure 7-4 The optimal location for trans-septal puncture. Diagrammatic
representation of the structures visualized in 40 degrees right anterior
oblique (RAO) projection. Limits of the atria are depicted behind the aorta.
The pigtail catheter positioned in the noncoronary aortic cusp defines the
posterior boundary of the aortic root. X, The point of intended atrial septal
puncture. (From Croft CH, Lipscomb K: Modified technique of transseptal
left hear t catheterization. J Am Coll Cardiol 5:904–910, 1985.)
Plane of mitral valve
Left ventricle
what point the needle leaves the catheter end, and marks this
distance with the right thumb. The right thumb position is used to
keep the needle inside the catheter and protect from inadvertent
needle damage.
2. To mark the aortic valve level as an anatomic reference point,
place a pigtail catheter in the sinus of Valsalva at the aortic valve.
For patients with an aortic valve prosthesis visible on fluoroscopy
or when echocardiography is used, a pigtail catheter is not
needed. In all cases, monitor the aortic or systemic arterial pressure during trans-septal puncture.
3. Use fluoroscopy to determine landmarks for puncture. Figure 7-4
shows a right anterior oblique (RAO) projection, at which a
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horizontal line is drawn from the lower end of the pigtail catheter
that intersects with the vertical line of the RA border. The fossa
ovale is typically 1 cm below this line at its midpoint. If a left
anterior oblique (LAO) projection is available, the operator can
help to ensure a posterior orientation of the needle trajectory. In
this view, the location of the fossa ovale is typically two-thirds
of the distance from the aorta to the posterior wall of the LA
(Fig. 7-5).
4. Advance a 0.032-inch guidewire to the SVC via the right femoral
vein.
5. Advance the trans-septal catheter (and sheath) over the guidewire
to the SVC. It is important to have the end of the catheter in the
SVC before removing the guidewire, because this position minimizes the need for superior movement of the assembly. Withdraw
the wire and then aspirate the catheter.
6. Advance the trans-septal needle through the catheter. As the
trans-septal needle is passed through the trans-septal catheter to
the SVC, rotate it at three points along its course to facilitate movement through the pelvic vessels. The first is at the iliac crest, the
second over the spine near the renal vein, and the third at the
inferior junction of the cardiac silhouette. The needle should
rotate freely over these three segments and slide smoothly up
through the trans-septal catheter. Damage to the catheter or injury
to the patient can occur if the needle does not rotate freely.
Position the needle in the SVC with the needle tip kept within
the catheter, whose position was previously noted by the finger
separation of the hub from the sheath. Connect the needle to a
pressure transducer for continuous observation of atrial pressure
during septal crossing.
7. Withdraw the catheter and needle assembly, now held fixed
together, downward (caudally) from the SVC into the RA with a
clockwise rotation of the metal arrow indicator of the needle
angle pointing posterior-medially between a 3 o’clock and 5
o’clock position (see Fig. 7-3).
8. On withdrawal downward into the RA, pass the catheter assembly
over the aortic knob with a forward motion, and on further withdrawal, pass under the superior limbus into the fossa ovale.
Slightly advance the catheter-needle assembly until making
secure contact with the atrial septum. Approximately 15% to 20%
of patients have a patent foramen ovale, which allows unobstructed passage of the catheter assembly into the LA without
needle puncture.
9. After the catheter and needle assembly makes secure contact with
the atrial septum, maintain firm pressure on the sheath and catheter
and advance the needle into the septum while continuously monitoring pressure waveforms. When echocardiography is used,
per form imaging to demonstrate indentation of the atrial septum
by the needle and a posterior orientation of the assembly
(Fig. 7-6).
10. Observe the LA pressure waveforms to note entry of the needle
into the LA. If the operator is in doubt about the location of the
needle tip, aspirate blood to determine oxygen saturation (which
should be arterial) or inject a small amount of contrast material
under fluoroscopy. After confirming the proper positioning of the
needle in the LA, advance it slightly and advance the catheter over
the needle with a counterclockwise rotation of the needle, which
permits the trans-septal catheter to turn anteriorly toward the
mitral valve. The operator can give small amounts of contrast
during manipulation across the septum to help avoid injury of the
posterior or superior walls of the atrium.
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Special Techniques
A
B
C
TV
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Figure 7-5
posterior imaging, with the tip of the trans-septal catheter inferior and medial
to the aor tic valve. B, On the lateral projection, the trans-septal puncture
site is at approximately two-thirds of the distance from the aortic valve to
the posterior wall of the left atrium (LA). C, In the right anterior oblique (RAO)
view, the trans-septal dilator engages the fossa ovalis posterior to the pigtail
catheter (aortic valve) but anterior to the right atrial (RA) silhouet te (dashed
line). TV, Tricuspid valve . (From Babaliaros VC, Green JT, Lerakis S, et al:
Emerging applications for transseptal left heart catheterization old techniques for new procedures. J Am Coll Cardiol 51:2116–2122, 2008.)
A, The pigtail marks the location of the aortic valve on anterior-
11. The operator can advance the sheath over the trans-septal catheter. This advancement can be performed with or without removal
of the needle, with fixation of the catheter. Of note, during the
advancement of the sheath, the relatively abrupt transition
between the catheter and sheath can cause the assembly to be
pushed off the atrial septum back into the RA with loss of transseptal access. To help minimize this error, use gentle forward
pressure with care to avoid inadvertent forward movement of the
assembly. This forward pressure can be applied after withdrawing
the needle and reinserting a preshaped guidewire (e.g., Inoue
wire).
12. To access the LV, insert a guidewire into the trans-septal catheter
or sheath and advance across the mitral valve and into the LV. Do
not turn the sheath without a wire or dilator in place, because it
is thin-walled and easily kinked. Pass a balloon catheter (filled
with carbon dioxide to minimize risk in the event of balloon
rupture) through the trans-septal sheath, and float the catheter
into the LV. The operator can transduce the balloon catheter for
ventricular pressure or use it as a rail for passing the trans-septal
catheter into the LV.
13. Give heparin (70 U/kg IV) once trans-septal access has been successfully obtained.
Of note, the fossa ovale is located in the middle third of the atrial
septum and is concave toward the LA in a normal heart. Valvular
disease may significantly alter the location of the fossa ovale. In aortic
valve disease, a dilated ascending aorta may displace the fossa superiorly and anteriorly. In mitral valve disease, the LA usually enlarges
posteriorly and inferiorly and displaces the fossa ovale inferiorly. In
severe mitral disease, the fossa may become everted and displaced
into the lower third of the septum. This makes the fossa difficult to
locate on catheter descent, and trans-septal puncture technique must
be modified accordingly.
In some patients, the atrial septum can be thickened and difficult
to cross with the trans-septal needle or catheter assembly. A transseptal method using radiofrequency energy to ablate the atrial septum
has been developed. A needle, which is fully insulated excepted for
the 21-gauge tip, is connected to a generator that creates monopolar
output to deliver 10 W of energy for 2 seconds (Baylis Medical
Company, Quebec, CA). Comparing the radiofrequency method with
conventional trans-septal needle techniques, a randomized trial
showed a shorter time to trans-septal puncture (2.3 min vs. 7.3 min)
and a higher rate of success (100% vs. 72.2%) with radiofrequency.
When there is concern about the forward pressure needed to
advance a trans-septal needle or catheter assembly, the atrial septum
can be initially crossed with a low-profile guidewire. In this technique,
the catheter assembly and needle is used to indent the septum, followed by advancement of a 135-cm 0.014-inch nitinol wire (SafeSept,
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A
Special Techniques
LA
RA
LA
RA
B
Figure 7-6
cardiography shows tenting of the atrial septum with the catheter pointed
posteriorly and away from the aortic valve. LA, Left atrium; RA, right atrium.
(From Babaliaros VC, Green JT, Lerakis S, et al: Emerging applications for
transseptal left hear t catheterization old techniques for new procedures.
J Am Coll Cardiol 51:2116–2122, 2008.)
Two-dimensional (2D; A) and three -dimensional (3D; B) echo-
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Special Techniques 337
Pressure Products, San Pedro, CA). The tip of this wire is sharp to allow
relatively easy passage across the septum; once across, the preshaped
configuration helps to prevent inadvertent injury from forward
advancement of the catheter assembly into the LA.
Risks of Trans-Septal Catheterization
Punctures of the aortic root, the coronary sinus (CS), or the posterior
free wall of the atrium are potentially lethal complications (Box 7-1).
In patients who have not been given anticoagulants, the 21-gauge tip
of the needle rarely causes a problem. However, if the large transseptal catheter assembly is advanced into these spaces, cardiac tamponade can easily occur. The catheter-needle combination should not
be advanced if the operator is not satisfied with the position of the
trans-septal catheter in the right atria. If the catheter assembly is not
in the correct position, the operator must remove the trans-septal
needle, reinsert the guidewire to the SVC, and reposition the assembly
toward the fossa ovale, as indicated earlier.
Direct Left Ventricular Puncture
The development of retrograde arterial catheterization and transseptal techniques has enabled clinicians to access the LV without
direct puncture in the vast majority of patients. Nonetheless, there
remain diagnostic and therapeutic indications for this technique,
especially with the advent of transapical transcatheter aortic valve
replacement (TAVR). Due to the high potential for complications, only
experienced operators should perform direct LV puncture.
Indications
The indications for direct left ventricular puncture are:
1. Direct hemodynamic assessment of the LV and left ventriculogra-
phy, when diagnostic data cannot be obtained using other vascular
access or from noninvasive imaging evaluations. This indication
occurs mainly in patients who have undergone replacement of the
mitral and aortic valves with mechanical prostheses.
2. Structural heart interventions whose therapies are either deliv-
ered through the LV apex or require the creation of transcatheter
heart rails for delivery. These therapies include mitral valve
placement and percutaneous closure of paravalvular prosthetic
regurgitation.
Direct LV puncture should be avoided in patients with intracardiac thrombus and those on therapeutic anticoagulation.
Box 7-1 Risks Related to Trans-Septal Catheterization
• Cardiac per foration
• RA
• Posterior LA
• LA appendage
• Pulmonary vein
• LV
• Puncture into the aortic root
• Pericardial tamponade*
• Embolus from the LA
LA, Lef t atrium; LV, lef t ventricle; RA, right atrium.
*Almost all deaths related to trans-septal catheteriza tion are a result of tampona de.
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Special Techniques
Technique
Direct LV puncture is most commonly performed with echocardiographic guidance. Recently, techniques with guidance from CT overlay
in the catheterization laboratory also have been developed (see
Fusion Imaging to Facilitate Cardiac Catheterization later).
When relying on echocardiography, the LV apex is imaged from
the apical window to determine the direction of the long axis of the
LV at a position that is superior to the rib margin. The operator memorizes this angle and marks the position in the chest with an indelible
pen. Following sterile prepping of the puncture area, an 18-gauge
needle with a Teflon sheath is inserted. Some operators prefer needles
with stylets to avoid coring of the myocardium, whereas others choose
to connect the needle to a pressure transducer for hemodynamic
monitoring during insertion. Once the needle enters the LV, it is
advanced 2 to 3 mm further to ensure that the outer Teflon sheath is
fully advanced into the LV. The needle is then removed, leaving the
sheath in place for diagnostic use or therapeutic interventions. Note
that after its removal, the needle should not be reintroduced into the
Teflon sheath in the patient. Figures 7-7 and 7-8 illustrate a typical case
of direct LV puncture and associated hemodynamics.
Following completion of the procedure, the apical access site can
be closed with placement of an occlude device. Currently, there are
no FDA-approved devices for closure of the LV apex, but several
devices (AMPLATZER Muscular VSD Occluder, AMPLATZER Duct
Occluder, and AMPLATZER Vascular Plug II, St. Jude Medical, St. Paul,
MN) have been used. Following reversal of anticoagulation, the distal
disk of the closure device is withdrawn until secured to the endocardial surface of the LV. Positioning can be identified by landmarks on
adjunctive imaging and confirmed by contrast injection through the
sheath. The entire device is then uncovered, such that the proximal
disk is on the epicardial surface. At that time, elongation and systolic
compression of the device should be noted through the cardiac cycle
to confirm correct placement.
Complications
The patient should be observed carefully for hemopericardium, hemothorax, or pneumothorax. Should any of these complications occur,
they can be treated with direct aspiration or surgery as needed. A
vasovagal reaction with bradycardia and hypotension may be encountered. Bleeding complications may result from laceration of the left
anterior descending, its branches, or intercostal arteries. Patients who
have had previous cardiac surgery usually have obliterated pericardial
space, which decreases the likelihood of cardiac tamponade.
Fusion Imaging to Facilitate Cardiac
Catheterization
When performing cardiac catheterization, fusion imaging, which
merges two or more imaging sources (e.g., echocardiography, CT, and
fluoroscopy), helps to overcome the spatial limitations of a single
imaging source. This integration, made possible through the use of
proprietar y software, leads to benefits of individualized planning and
guidance to improve procedural accuracy and safety.
Computed Tomography Angiography–Fluoroscopy
Fusion Imaging
Fusion imaging using computed tomography angiography (CTA) and
fluoroscopy imaging provides a three-dimensional (3D) model that
allows important cardiac and surrounding structures to be identified,
while preserving the temporal resolution of fluoroscopy. All patients
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P
A
M
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Special Techniques 339
P
4
A
B
Figure 7-7
lography through the pigtail catheter (P4) positioned from the left ventricular
apex. The supravalvular pigtail catheter (P) is positioned above the aor tic
ring (A), which is adjacent to the mitral ring (M). Multiple pacing leads
and two pulmonary ar tery catheters are positioned near the supraaortic
pigtail catheter. Contrast injection during ventriculography shows no mitral
regurgitation.
Cineangiographic frames before (A) and during (B) left ventricu-
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200 mm Hg
Figure 7-8 Left ventricular (LV), lef t atrial (L A), and aortic (Ao) pressures
(0- to 200-mm Hg scale) showing aortic and mitral prosthetic valve gradients. Note the influence of the paced beats on the valve gradients.
Special Techniques
LV
Ao
LA
undergo a preprocedural CTA (preferably, ≥256-slice) with retrospective electrocardiogram (ECG)-gating. DICOM data of a single phase,
typically diastolic, 75% of the R–R interval are subsequently uploaded
to the fusion workstation. These preprocedural two-dimensional (2D)
images are volume-rendered in three dimensions, followed by segmentation to identify the ventricles, valves, ribs, coronary arteries, and
great vessels, with optimization depending on information needed
(Figs. 7-9 and 7-10). Landmarks are placed for each site-specific access
approach. The CTA images are registered by markers (e.g., bronchi/
carina, prosthetic valve frame, pacemaker wires, aorta, and coronary
arteries) in two views taken ≥30 degrees apart. For live overlay, volume-
rendered, 3D images are replaced with an outlined view of the segmented cardiac structures. During the procedure, 3D rendered images
are displayed in real time with the same perspective as the synchro nized fluoroscopic C-arm.
For transapical access, required cardiac structures include the
ribs, left lung, and left anterior descending artery. Preselected landmarks are placed to identify skin entry, LV epicardial entry site, and
structural defect. A “safe path” or cylinder is generated, connecting
the landmarks such that a direct line is made into the LV away from
lung parenchyma, coronary arteries, and papillary muscles (Fig. 7-11).
The skin is entered with the needle trajectory confirmed in RAO and
LAO views. The LAO view is en face such that the landmarks and
cylinder are completely in line, generating a target into the LV. With
CTA-fluoroscopic fusion imaging, the accuracy of transapical puncture is usually within 5 mm of intended entry.
For trans-septal puncture using CTA-fluoroscopic fusion imaging,
a landmark is placed on the interatrial septum typically at the fossa
ovalis (Fig. 7-12). Standard trans-septal puncture techniques, as
described earlier, can then be used.
Transesophageal echocardiography–Fluoroscopy
Fusion Imaging
Transesophageal echocardiography (TEE)–fluoroscopy fusion imaging merges live echocardiography and fluoroscopy in a volumetrically fused image dataset. This type of imaging does not require
contrast and overcomes some limitations of CTA, including lack of
motion compensation and nonsimultaneous data acquisition. Nonetheless, imaging with TEE-fluoroscopy is restricted to the echocardiographic field of view. In TEE-fluoroscopy, 2D and 3D images are
obtained using the IE33 echocardiographic system with an X7-2t TEE
probe (Philips Healthcare, Andover, MA). The fluoroscopy table is
placed with the echocardiographic probe tip at the center of the registration window with the entire TEE faceplate well visualized.
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A B
Special Techniques 341
C
Figure 7-9 Images showing three -dimensional (3D) volume-rendering, seg-
mentation, and placement of landmarks. Preprocedural two-dimensional
(2D) computed tomographic angiography (CTA) images are 3D volumerendered and automatically segmented to identify cardiac structures including the left ventricle (LV; red), left atrium (green), and aor ta (orange).
Additional structures that can be manually segmented include the coronary
arteries (purple; extending from the aortic root), mitral annular calcification/
prosthetic valve (yellow), lung (purple), and ribs (orange). Landmarks are then
placed to identify skin, LV entr y, center of mitral prosthesis (MV), paravalvular leak (PVL), and trans-septal entry (blue circle; TRSEPT ). A “safe path”
is generated, connecting the skin and LV entry landmarks toward the PVL
(red cylinder) or MV (yellow cylinder) for transapical access. A, Full-volume
view; B, axial, coronal, and sagittal planes; C, cutplane view with the LV
removed. AV, Atrioventricular node.
Landmarks are placed and subsequently overlayed onto fluoroscopy.
Changes in position or angulation of the TEE probe are immediately
re-registered and updated on the live fluoroscopic image. Four viewing
windows are available: (1) echo view, which mimics the display of
traditional echocardiographic images; (2) C-arm view, which displays
the echocardiographic images in reference to the C-arm orientation;
(3) free view, which allows the interventionalist and echocardiographer to freely move the echocardiographic image while keeping track
of virtual C-arm orientation; and (4) x-ray view, the traditional fluoroscopic 2D image with overlayed landmarks (Fig. 7-13). For trans-septal
access, a landmark is placed on the interatrial septum at an appropriate site on the septum in x-plane and confirmed in a 3D view. These
views can then be used to guide trans-septal access.
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