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64 1—BUILDING BLOCKS OF STRUCTURAL INTERVENTION
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Fig. 5.5 Transseptal puncture guided by biplane TEE. FO, Fossa ovalis; IVC, inferior vena cava; LA, left
atrium; RA, right atrium; RAA, right atrial appendage; SVC, superior vena cava; TEE, transesophageal echocardiography. The arrows illustrate tenting of the fossa ovalis in a mid-mid position on the superior-inferior
(left) and the anterior-posterior (right) aspects of the septum, respectively.
catheter (e.g., AcuNav, Siemens, Malvern, PA; ViewFlex, St. Jude, St. Paul, MN) is advanced
to the mid-RA and rotated clockwise to identify the intraatrial septum. A slight posterior tilt
of the transducer (AP knob) brings the FO into view (long-axis septal view). This view is
comparable, but not identical, to the “long-axis” view on TEE, and hence can be used to
assess the height of the puncture (Fig. 5.6). The catheter can then be withdrawn slightly to
a low RA position and rotated slightly leftward using the right–left knob to yield the “shortaxis septal view,” which delineates the anterior and posterior borders of the FO.
Fig. 5.6 Intracardiac echocardiography for transseptal puncture. (A) The fossa ovalis as seen in the
“septal” view. (B) Tenting of the fossa ovalis with the transseptal needle. (C) The transseptal sheath across
the fossa ovalis in the left atrium. FO, Fossa ovalis; IVC, inferior vena cava; LA, left atrium; RA, right atrium;
SVC, superior vena cava. (Reprinted with permission from Alkhouli M, Rihal CS, Holmes DR Jr. Transseptal
techniques for emerging structural heart interventions. JACC Cardiovasc Interv. 2016:26;9[24]:2465-2480.)
5—TECHNIQUES OF TRANSSEPTAL PUNCTURE 65
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3. Fusion imaging: Novel imaging systems (e.g., Echo Navigator, Philips, Amsterdam,
Netherlands) offer fusion of TEE 1 fluoroscopy images, allowing a real-time, crossintegrated view of both modalities. Newer imaging modalities (3D-TEE, computed
tomography [CT]-derived 3D-augmented fluoroscopy, real-time magnetic resonance
imaging, and rotational angiography) have been shown to be very useful in guiding
SHD interventions, but their incremental values in guiding TSP have not been fully
evaluated.
SITE-SPECIFIC PUNCTURE
The advent of complex SHD interventions that require LA access has called attention to the
key role of site-specific transseptal access in optimizing the results of these procedures.
example, optimal guiding-catheter position in the LA is a crucial initial step of transcatheter
mitral valve repair with the MitraClip (Abbott Vascular, Santa Clara, CA); a posterior and
slightly superior puncture is desired to achieve the recommended distance of 3.5 to 4.5 cm
between the puncture and the valve planes when central mitral regurgitation is targeted,
whereas higher and lower puncture locations are more suitable for medial and lateral regurgitant jets, respectively. In percutaneous balloon mitral valvuloplasty and transseptal mitral
valve–in–valve implantation procedures, a midposterior puncture allows coaxial access to the
valve plane and adequate working height in the LA. Similarly, in percutaneous left atrial appendage (LAA) closure procedures, the success of the procedure relies on coaxial alignment of
the delivery sheath along the long axis of the LAA. This is best achieved with an inferiorposterior TSP (Fig. 5.7).
2,3
For
Fig. 5.7 Site-specific transseptal puncture for various intracardiac interventions. Red: MitraClip, para-
valvular leak closure (a higher crossing site is recommended for medial leaks, and a lower crossing site is
recommended for lateral leaks—dashed red circles). Yellow: Transseptal patent foramen ovale closure. Blue:
Percutaneous left ventricular assist device placement, hemodynamic studies. Green: Left atrial appendage
closure. Orange: Pulmonary vein interventions. (Reprinted with permission from Reprinted with permission
from Alkhouli M, Rihal CS, Holmes DR Jr. Transseptal techniques for emerging structural heart interventions.
JACC Cardiovasc Interv. 2016:26;9[24]:2465-2480.)
66 1—BUILDING BLOCKS OF STRUCTURAL INTERVENTION
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Complications of Transseptal Catheterization
Complications of TSP, although rare, are associated with major morbidity and mortality.
Detailed knowledge of the spatial relationship of the atrial septum to surrounding structures and
its variations is a key to enhance the safety of the procedure. The operator should also develop a
contingency plan and a systematic approach to the most common potential complications of TSP.
Cardiac tamponade: Cardiac tamponade during TSP may result from inadvertent advance-
ment of the needle or the transseptal sheath into the free atrial wall or excessive manipulation of
large-bore sheaths/guides in the LA or the LAA. The incidence of cardiac tamponade ranges
between ,1% in diagnostic hemodynamic studies to 1% to 2% with mitral valve interventions
and 2% to 3% with LAA closure. The clinical presentation varies according to the size of the
implicated device, the structure that is affected (RA, LA, LAA), and the hemodynamic and coagulation status of the patient at the time of the event. Immediate recognition and treatment with
pericardiocentesis is lifesaving. Therefore pericardiocentesis kits and competency in the procedure are essential requirements for any intervention involving TSP. If tamponade is a result of an
inadvertent passage of a sheath or a catheter through the free wall of the atrium, it is vital not to
prematurely withdraw the perforating catheter. Maintaining sheath or catheter access through
the perforation allows stabilization of the perforation until a definitive rescue intervention is
undertaken. The feasibility of Amplatz septal and vascular occluders in sealing iatrogenic cardiac
and aortic perforations has been demonstrated in several reports.
Thromboembolism: Thrombus formation can occur before, during, or after TSP, mainly due to
underanticoagulation (Fig. 5.8). To mitigate these risks, we routinely administer 2000 to 5000 units
of unfractionated heparin before TSP and 150 to 200 units/kg to achieve an ACT .250 to 300
after obtaining LA access to the LA. Maintaining an activated clotting time (ACT) .300 seconds
during pulmonary vein isolation (PVI) has been suggested to prevent LA thrombus formation. The
high ACT is well tolerated, and it is important not to rely on coronary doses of heparin while intervening in the LA. In high-risk patients with persistent LAA clot or dense smoke, cerebral embolic protection can be utilized. If a thrombus is detected on echocardiography, vigorous aspiration
and intensifying anticoagulation are often adequate to resolve it.
2
Air embolism: Air emboli may enter the LA because of inadvertent injection of air during
catheter/sheath flushing or due to inadequate deairing of the delivery system, especially in patients with low LA pressure. Although the majority of air emboli are subclinical, myocardial infarction, stroke, hypotension, and cardiac arrest may occur if large emboli have entered the arterial
circulation. This complication can be largely prevented with meticulous deairing of the delivery
sheath and adequate hydration to increase LA pressure during the procedure. If air emboli are
suspected, prompt treatment with high-flow oxygen, manual thrombectomy, vasopressors, and
volume expansion is paramount. Hyperbaric oxygen is reserved for patients with large air emboli
leading to cerebral ischemia, although the prognosis of those patients is guarded despite treatment. Although the development of ST-segment elevation should always raise suspicion for air
embolism, transient self-limiting ST elevation may occur due to a vasospastic neutrally mediated
mechanism (Bezold–Jarisch reflex).
Iatrogenic atrial septal defect: Persistent septal defect after transseptal structural interventions
is not uncommon, and its incidence is linearly related to the diameter of the transseptal sheath/
5
system.
At 6-month follow-up, persistent septal defects were found in 6.8%, 20%, and 50% of
patients who underwent LAA closure (12F), mitral balloon valvuloplasty (14F), and transcatheter mitral valve repair (22F), respectively (Fig. 5.9). Many patients with persistent septal defect
are asymptomatic or mildly symptomatic, but a large defect can result in severe heart failure
symptoms or acute hypoxemia. In patients with large residual septal defects, advanced ventricular
dysfunction, or pulmonary hypertension, routine surveillance of the defect with serial echocardiograms may be warranted (Fig. 5.10).
2,3
5—TECHNIQUES OF TRANSSEPTAL PUNCTURE 67
Transseptal Catheter Internal Diameter French (∗Fr)
ect (%)
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Fig. 5.8 Thromboembolism during transseptal cardiac catheterization. (A–B) Thrombus on the trans-
septal sheath in the right atrium detected on transesophageal echocardiogram (arrow). (C–D) Thrombus
formation (arrow) on the transseptal sheath in the left atrial (LA) detected on intracardiac echocardiogram.
(Reprinted with permission from Alkhouli M, Rihal CS, Holmes DR Jr. Transseptal techniques for emerging
structural heart interventions. JACC Cardiovasc Interv. 2016:26;9[24]:2465-2480.)
P < 0.001
50
50.0%
40
30
23.1%
20
10
6.8%
2.2%
0
Persistent Iatrogenic Atrial Septal Def
∗
8Fr
Fig. 5.9 Transseptal catheter internal diameter (French).
12Fr
∗
14–20Fr
∗
22Fr
∗
68 1—BUILDING BLOCKS OF STRUCTURAL INTERVENTION
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Fig. 5.10 Iatrogenic atrial septal defect after transseptal mitral valve–in–valve implantation. (A) Atrial
septostomy: balloon atrial dilatation of the intraatrial septum before valve placement (asterisk). (B) Transesophageal echocardiogram assessment showing a large residual septal defect with left-to-right shunt (yellow arrow).
(C) Three-dimensional transesophageal echocardiography reconstruction showing the irregular shape of the
defect. (D) Hemodynamic assessment of aortic (red) and left atrial pressure (green) before (top rows) and after
(lower rows) valve implantation. (E) Percutaneous septal defect closure with a 25-mm Cardioform septal occluder. AV, Aortic valve; LA, left atrium; RA, right atrium. (Reprinted with permission from Alkhouli M, Sarraf M,
Holmes, DR. Iatrogenic atrial septal defect. Circ Cardiovasc Interv. 2016;9:e003545.)
Other, less common complications of TSP include venous perforation, aortic puncture, coro-
nary dissection, septal tear, detachment of the sheath’s tip, and acute pericarditis.
Competency in Transseptal Puncture
Data on training in TSP have suggested that the steepest area of the learning curve can be passed
with the performance of 25 supervised cases to minimize procedural complications. Although
this hands-on experience is achievable in the majority of SHD fellowship programs, additional
venues for training include virtual reality simulators (e.g., Procedicus VIST, Mentice AB, Gothenburg, Sweden; Simbionix, Cleveland, OH) and cross-training with other specialties that
routinely perform TSP.
Conclusion
TSP is an essential skill for a growing number of structural heart interventions. Contemporary
TSP utilizes advanced imaging modalities and novel ancillary tools to achieve safe site-specific
puncture even in patients with difficult anatomy.
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References
1. Ross J Jr., Braunwald E, Morrow AG. Transseptal left atrial puncture: New technique for the easurement
of left atrial pressure in man. Am J Cardiol. 1959;3:653-655.
2. Alkhouli M, Rihal CS, Holmes DR Jr. Transseptal techniques for emerging structural heart interventions.
JACC Cardiovasc Interv. 2016;9(24):2465-2480.
3. Singh GD ST, Rogers JH. Targeted transseptal access for MitraClip percutaneous mitral valve repair.
Intervent Cardiol Clin. 2016;5:55-69.
4. Raphael CE, Alkhouli M, Maor E, et al. Building blocks of structural intervention: A novel modular
paradigm for procedural training. Circ Cardiovasc Interv. 2017;10(10). pii: e005686.
5. Alkhouli M, Sarraf M, Zack CJ, Holmes DR, Rihal CS. Iatrogenic atrial septal defect following transseptal cardiac interventions. Int J Cardiol. 2016;209:142-148.
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Abstract: Transseptal catheterization is a key element of many contemporary structural heart
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interventions. This chapter provides an overview of transseptal catheterization techniques, with
a special focus on challenging transseptal access navigation and procedural complications.
Keywords: Transseptal catheterization, transseptal puncture, intraatrial septum, fossa ovalis,
structural heart intervention.
e1
SECTION 2
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Aortic Valve Interventions
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CHAPTER 6
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Balloon Aortic Valvuloplasty
Claire E. Raphael David R. Holmes Jr.
Background
Aortic stenosis (AS) is common in the elderly population, with a prevalence of approximately 3%
in patients over 75 years old. The prognosis of symptomatic severe AS is poor, with a 50% mortality rate at 2 years; therefore valve replacement is usually recommended once symptoms of
shortness of breath, heart failure, or angina occur.
In the majority of elderly patients, the aortic valve is trileaflet (Fig. 6.1, left panel). Patients
with severe AS below the age of 65 usually have a congenital bicuspid aortic valve (see Fig. 6.1,
central panel). In both cases, the aortic valve becomes progressively calcified with age and leaflet
movement is restricted. Rheumatic heart disease may cause premature calcification of the aortic
and/or other valves (see Fig. 6.1, right panel).
Indications
Balloon aortic valvuloplasty (BAV ) is designed to fissure or fracture the calcified aortic
valve and separate fused commissures. The role of BAV depends on the specific clinical
setting. In congenital AS where the valve is not significantly calcified, benefits are usually
quite durable and it is an accepted destination therapy. This is different to elderly patients
with severe calcific degenerative AS in whom BAV is largely performed as a palliative procedure or a bridge to aortic valve replacement (AVR)/or transcatheter aortic valve replacement (TAVR).
The reluctance to perform BAV in calcific AS relates to the fact that the injury caused by the
balloon also promotes progressive collagenization and formation of new scar tissue, leading to
short-lived reduction in aortic gradients and valve area. Symptomatic improvement may persist
for up to 6 to 12 months in selected cases after BAV, but the mortality remains high and similar
to untreated patients. Restenosis usually occurs within 6 to 12 months of BAV in calcific AS, and
results are not durable (Box 6.1).
Other Potential Indications
There are no class I indications for BAV because it has not been shown to have lasting benefits
in any disease state.
Young Patients With Congenital Aortic Stenosis
In young patients with congenital AS, BAV may be considered as a therapeutic option. It is
thought to have a more durable effect in younger patients who do not have significant valvular
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