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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3676_Библиотеки_им_академика_М_И_Перельмана
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J.J. Lee et al.
13.1.3 Diagnosis
Normal anatomic features of the pulmonary
venous trunks draining into the left atrium.
13.1.4 Discussion
Although, there are three lobes in the right lung
and two in the left lung, the right middle and the
superior lobar veins join together, and, most
commonly, two pulmonary veins (PV) from each
lung drain into the left atrium [1]. Other anatomical variations include:
1. The three right lobar veins could remain separate. Such information can be useful to ensure
that all PVs are electrically isolated [1].
2. The two left PVs may form a single trunk.
This single trunk usually has a larger ostium.
A larger ostium can allow limited lesion application at the ostium with greater confidence in
avoiding pulmonary vein stenosis [1].
3. An accessory lobar vein from each lobe can
join and augment the two left PVs. On the contrary, this accessory lobar trunk has a smaller
ostium. This accessory vein and its small
ostium should be noted before the procedure to
ensure that all PVs are electrically isolated and
to avoid pulmonary vein stenosis [1].
Left atrial size is also evaluated with
CCTA. The enlargement of the LA can estimate
the duration and the difficulty of the ablation procedure; it is also a risk factor for stroke and atrial
fibrillation before and after the procedure [5, 6].
In the AFFIRM study, large transthoracic echocardiographic LA sizes were associated with
recurrent AF (HR = 1.21, 1.16, and 1.32 for mild,
moderate, and severe enlargement, respectively)
[7]. Moreover, according to the substudy of the
ENGAGE AF-TIMI 48 trial, there were strong
correlations between increasing abnormalities of
LA structure and function with greater burdens of
AF and higher CHADS
stroke risk [8].
score, an estimate of
2
13.1.5 Pearls and Pitfalls
Radiofrequency ablation to modify the atrial
myocardial substrate should be considered for
patients with atrial fibrillation refractory to
conventional pharmacological therapy [9].
CCTA could provide crucial information prior
to the EP procedure, by demonstrating patient’s
coronary anatomy for the pre-procedural
guideline.
13.2 Case 13.2
13.2.1 Findings
Intra-operative imaging for EP procedure:
Figure 13.1d is an image of a left atrium volume rendered from a preoperative CT. Four pulmonary veins and a left atrial appendage are
visualized in this figure.
Figure 13.1e is a 3D Fast Anatomical Mapping
(FAM) reconstruction (left) with a synchronized
posterior-anterior view of the CT (right). Note
that an esophagus has been reconstructed with
the same technique to delineate its location relative to the posterior wall of the LA.
Figure 13.1f is again a 3D FAM with the corresponding left anterior oblique (LAO) CT. In
this figure, an ablation catheter is shown pointing
anteriorly and superiorly (note the vector) on a
carina between a left inferior pulmonary vein
(LIPV) and a left superior pulmonary vein
(LSPV). An electrical activity sensing catheter is
also visualized inside the LIPV. The local intracardiac electrograms inside the pulmonary veins
show electrical activity.
Figure 13.1g shows an electrical isolation of
the LIPV. Here, we can see that there is no electrical activity on the local intracardiac electrograms while the catheter is in the LIPV. The blue
dot is used as a location marker for the electroanatomical location of an applied lesion where
complete electrical isolation was achieved.
Figure 13.1h is a right posterior view of the
3D FAM and a corresponding CT. This real-time
13 Cardiac CTA: Electrophysiology
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graph view allows us to monitor the force applied
as the distal tip of the catheter, impedance, temperature, and power throughout the ablation.
13.2.2 Diagnosis
Successful pulmonary vein isolation without
complications.
13.2.3 Discussion
The electrophysiologist can utilize this 3D reconstruction to safely maneuver the catheter inside
the heart and precisely locate the ablation points.
There is a thin layer of fat, insulating the posterior wall of the LA from the anterior esophagus
[10]. This relationship between the left atrium and
the esophagus is carefully evaluated before the
procedure and monitored during the procedure to
avoid esophageal injury during the procedure.
During a post-op follow-up visit, patient
reported feeling well and no longer having any
symptoms of atrial fibrillation. Patient is active
with no exertional symptoms and no shortness of
breath.
13.2.4 Pearls and Pitfalls
A careful, efficient intra-operative maneuvering
of the ablation catheter is possible with the CCTA
reconstruction superimposed with the CARTO,
3D electro-anatomic and non-fluoroscopic system
[11]. This has increased the safety of the procedure while cutting down both the procedure and
fluoroscopy times.
13.3 Case 13.3
13.3.1 History
A 56-year-old male with history of AF, status
post ablation 8 years ago at an outside hospital,
presented with recurrent AF. Three years ago, 5
years after his initial ablation, the patient started
to redevelop symptomatic palpitations and he
began taking flecainide and metoprolol. Despite
being on anti-arrhythmic therapy, the patient continued to complain of palpitations without significant shortness of breath.
Upon review of the outside hospital records,
there were no post-procedure images taken. The
pre-ablation echocardiogram demonstrated normal ventricular function and pulmonary pressures. The pre-procedural computed tomography
(CT) scan along with the three-dimensional (3D)
reconstruction was done on the procedural table
prior to the transeptal puncture, but did not pick
up the pulmonary vein stenosis.
Pulmonary vein potential mapping noted that
there was a potential at the ostium of the left
superior pulmonary vein. During the left atrial
catheter manipulation, the occlusion of the left
superior PV was discovered, secondary to the AF
ablation 8 years ago. The procedure was aborted
for further diagnostic workup.
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13.3.2 Findings
The computed tomography scan (Fig. 13.2a) and
the left atrium 3D reconstruction (Fig. 13.2b)
demonstrated subtotal occlusion of the left upper
pulmonary venous trunk. The lung perfusion
scan revealed significantly decreased left lung
perfusion (Fig. 13.2c). The levophase pulmonary
a
c
b
angiogram demonstrated well-developed collateral circulation from the left upper lobe to the
mid segment of the left lung and left upper PV
occlusion. The levophase angiogram of the right
middle lobe pulmonary arterial system demonstrated venous return confined to the area of the
lung supplied by the arterial vasculature
(Fig. 13.2d and e, respectively).
d e
Fig. 13.2 (a) Axial MIP (b) volume rendered (c) lung perfusion scan (d) left pulmonary angiogram. Arrow indicating
collateral (e) right pulmonary angiogram
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13.3.3 Diagnosis
Pulmonary vein stenosis on the LSPV.
13.3.4 Discussion
The patient’s asymptomatic PV stenosis is likely
secondary to compensatory hemodynamic adaptations via a well-developed collateral circulation. The patient has remained asymptomatic
since the incidental finding of PV stenosis and no
further attempts at AF ablation have been
undertaken.
13.3.5 Pearls and Pitfalls
The frequency of PV stenosis, a well-established
possible complication following an AF ablation
of pulmonary veins, has been declining due to the
improvement of technique. However, depending
on the technique and diagnostic modalities used,
PV stenosis occurs as often as 40% of patients
who underwent AF ablation [12].
PV stenosis acquired after AF ablation varies in severity from asymptomatic to nonspecific symptoms including persistent cough,
hemoptysis, and exertional dyspnea [13].
Given these nonspecific clinical symptoms,
physicians should be highly suspicious of the
diagnosis of PV stenosis in post-ablation
patients, and further evaluate patients with
multiple imaging modalities. In most cases of
PV stenosis, including severe cases, clinical
symptoms improve without intervention secondary to the compensatory hemodynamics
[12]; only about 22% of severe PV stenosis,
defined as more than 50% luminal occlusion,
required intervention [14]. Further supporting
the compensatory mechanism, absent perfusion on lung perfusion scan is indicative of
pulmonary artery to systemic collaterals,
which in our case is further demonstrated by
the pulmonary angiogram (Fig. 13.2d) [15,
16]. Patient undergoing repeat AF ablation
should undergo a CCTA to further evaluate the
possibility of PV stenosis preoperatively.
References
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tomography in pre-procedural planning of cardiovascular surgery and intervention. Insights Imaging.
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R, Liu Z, Augostini R, Kalbfleisch S, Smith MC,
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computed tomographic imaging with intraprocedural contrast esophagogram. Implications for catheter ablation of atrial fibrillation. Heart Rhythm.
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Cardiac Imaging 3:89–98.
12. Saad EB, Marrouche NF, Saad CP, et al. Pulmonary
vein stenosis after catheter ablation of atrial fibrillat io n:
MDCT of the left atrium
Comparison of
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emergence of a new clinical syndrome. Ann Intern
Med. 2003;138:634–8.
13. Yun D, Jung JI, YS O, Youn H-J. Hemodynamic
change in pulmonary vein stenosis after radiofrequency ablation: assessment with magnetic resonance
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14. Cappato R, Calkins H, Chen SA, et al. Updated
worldwide survey on the methods, efficacy, and safety
of catheter ablation for human atrial fibrillation. Circ
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Functional assessment of pulmonary vein stenosis using radionuclide ventilation/perfusion imaging. Chest. 2004;126(2):645–51.
Transcatheter Aortic Valve
https://t.me/med1917
Replacement Planning
Tariq A. Hameed
14
14.1 Transcatheter Aortic Valve
Replacement
Severe stenosis of aortic valve is associated with
high morbidity and there is high mortality in
untreated symptomatic patients. Severe aortic
stenosis is treated by surgical replacement of aortic valve. However, many patients are poor surgical candidates due to other comorbidities. In
these patients, the replacement of aortic valve by
transcatheter procedure is also a treatment option
with improved outcomes compared to medical
treatment.
Transcatheter aortic valve replacement
(TAVR), also called transcatheter aortic valve
implantation (TAVI), involves placement of a
bioprosthetic aortic valve within the native diseased aortic valve (Fig. 14.1a–f). The crimped
prosthetic valve contained within a sheath is
advanced into the native aortic valve via a catheter over a guide-wire during fluoroscopic guidance. Following appropriate alignment and
positioning, the valve is expelled out of the sheath
and depending on the type of valve, allowed to
expand or expanded over a balloon within the
native aortic valve apparatus. The prosthetic
valve is anchored in surrounding tissues with the
T.A. Hameed, MD, FCPS
Indiana University School of Medicine and Indiana
University Health, Indianapolis, IN, USA
e-mail: thameed@iupui.edu
native aortic valve leaflets displaced or sometimes crushed against the walls of the aortic root.
Two commonly used types of bioprosthetic
valves are:
• Balloon-expandable Edwards valves (Edwards
Lifesciences, Irvine, CA) including Sapien,
Sapien XT, and Sapien 3 (Fig. 14.2a, b).
• Self-expandable Medtronic CoreValve system
(Fig. 14.2c) including CoreValve and Evolut
R (Medtronic, Minneapolis, MN).
The transcatheter heart valve (THV) is usually
implanted via transfemoral approach (Fig. 14.3a),
which is preferred due to lower risk of potential
complications. This requires appropriate caliber
of access vessels such as iliac arteries and aorta to
accommodate the sheath with the valve. Less tortuous course of access vessels is desirable as
severe tortuosity limits catheter maneuverability
during valve implantation. In patients whose iliofemoral arterial anatomy is unfavorable, other
approaches are utilized, which include transapical approach via left ventricular apex (Fig. 14.3b–
d), direct aortic approach via ascending aorta
(Fig. 14.3e–g), and trans-axillary or subclavian
arterial approach.
Pre-TAVR workup of patients includes evalu-
ation with multiple imaging modalities including
echocardiography, catheter angiography, and
computed tomography (CT). The prosthetic
valves for TAVR come in a specific variety of
sizes and accurate determination of aortic valve
© Springer International Publishing AG 2018
C. Smuclovisky (ed.), Coronary Artery CTA, https://doi.org/10.1007/978-3-319-66988-5_14
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T.A. Hameed
a
b
c
Fig. 14.1 (a) Valve in sheath (b) Valve on partially expanded balloon (c) Valve on expanded balloon (d–f) Angiogram
of transcatheter valve deployment
14 Transcatheter Aortic Valve Replacement Planning
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383
d
e
f
Fig. 14.1 (continued)
384
a
b
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T.A. Hameed
c
Fig. 14.2 (a) Sapien 3 side view (b) Sapien 3 leaflet view (c) CoreValve 26 mm (a, b used with permission by Edwards
Lifesciences LLC, Irvine, CA. c is used with permission by Medtronic © 2016)
a
cd
b e
14 Transcatheter Aortic Valve Replacement Planning
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385
f
g
Fig. 14.3 (a) Commander Edwards valve via transfemo-
ral approach (b) Certitude Edwards valve via transapical
approach (c, d) Angiogram of transapical approach (e)
Certitude Edwards trans-aortic approach (f, g) Angiogram
of trans-aortic approach. (a, b, e are used with permission
by Edwards Lifesciences LLC, Irvine, CA. Edwards,
Edwards Lifesciences, CERTITUDE, COMMANDER,
Edwards SAPIEN, SAPIEN, SAPIEN XT, and SAPIEN 3
are trademarks of Edwards Lifesciences Corporation)
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