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Learning objectives
To learn how to:
Select the candidates for the technique
Optimise the use of equipment
Carry out the procedure
Adapt the procedure to specific subsequent structural interventions
Manage the complications
Introduction
Transseptal catheterisation was introduced in the late 50s1 and gained popularity with the introduction of the electrophysiological and structural heart interventions.2–10 Here, we shall describe the use of transseptal puncture (TSP) technique in the main transcatheter structural, and especially valve, interventions.
Indications
In current practice, the use of TSP has shifted from a diagnostic procedure, which is now used only exceptionally, to the first step before percutaneous interventions.
Transseptal puncture has been used worldwide for percutaneous mitral commissurotomy (PMC). More recently, it is increasingly performed for transcatheter interventions on the mitral valve (MitraClip procedure, annuloplasty or valve implantation: valve in valve, valve in a ring, valve in massive annular calcification), left atrial appendage closure and paravalvular leak closure. Finally, very recently it was also used for the new techniques of transcatheter mitral valve implantation.6 7 Its use for percutaneous aortic valve intervention has been almost entirely abandoned.10
Contraindications
The main contraindications to be excluded before TSP are as follows:
Left atrial thrombosis is an absolute contraindication for TSP if it is in the atrial cavity or on the septum. In patients with organised thrombosis localised in the apex of the left atrial appendage, TSP may be performed in exceptional cases where there is no therapeutic alternative. Left atrial myxoma also constitutes a contraindication. As a consequence, the performance of transoesophageal echocardiography (TOE) is recommended to exclude left atrial thrombosis before transseptal catheterisation. TOE should be performed immediately, or only a few days before the procedure depending on the intervention planned.11
The other following contraindications are relative:
Bleeding disorders.
If the patient receives vitamin K blockers, there is no consensus on the lower target International Normalized Ratio(INR) to be obtained before puncture. An INR <2 is mandatory in the absence of TOE guidance and for operators with limited experience of TSP. Others accept to perform the procedure when INR is <3. Intravenous heparin should be stopped 4 hours before TSP and reinitiated 2 hours later.
Severe kyphoscoliosis may be a contraindication. In such cases, TOE guidance is recommended.
Complex congenital disease resulting in severe anatomic distortion.
Obstruction or agenesis of the vena cava associated with azygos return are contraindications for femoral access. Similarly, an occluded filter in the vena cava contraindicates TSP.12–14
Repair of the interatrial septum by a patch or an occluder, is not a contraindication but may render the crossing difficult. In such cases, TSP may be performed, if possible, in the native septum or even inside the device.15
Dextrocardia is not a contraindication when TSP is performed by experienced operators under TOE guidance.w16
Technique
Equipment
The Brockenbrough needle (Medtronic or St Jude BRK) is the most frequently used. It is 70 cm long, has a curved tip and tapers distally.17 The arrow on the proximal part indicates the orientation of the needle.
The most commonly used catheters are 8F and comprise a dilator and a sheath (Mullins sheath or the Saint Jude SL 0 or 1 sheath). The shape of the latter allows for an easier catheterisation of the left superior pulmonary vein as an important step in the MitraClip or left atrial occlusion procedures. The catheters used for TSP in structural interventions are non-steerable18 (figure 1).
Equipment. (A) Two important features of the transseptal needle: the proximal arrow pointing in the same direction that the needle tip and the distal tip which is curved. (B) Catheter: Mullins sheath on top and ST Jude sheath at the bottom. (C) Illustration of how to maintain with two fingers the distance between the needle arrow and proximal end of the catheter in order to avoid protrusion of the needle outside the dilator.
Guidance of the procedure
Echo-guided TSP could be used for the following scenarios:
Targeted/site-specific TSP for structural interventions
Complex anatomy: severe thoracic deformity, complex congenital disorders, dextrocardia
Safety: low volume operator
Both TOE19 20 and intracardiac echocardiography (ICE)21 provide good visualisation of the septum, to guide the orientation towards the fossa ovale, to show the tenting of the septum and to monitor crossing. However, TOE guidance requires general anaesthesia, or at least analgesia, when TOE is performed. Alternatively, costs and the need for a second femoral access are drawbacks for ICE.
With growing experience, TOE guidance is limited to cases with difficult anatomy or when unexpected difficulties occur.3 On the other hand, TOE guidance is mandatory during TSP in structural valve interventions where it is therefore systematically used upfront. It is also helpful during the initial phase of training. Effective TOE guidance requires specific training and good understanding and collaboration between the interventionist and the echocardiographist, as well as the use of similar definitions.
In addition, TOE must also carefully look at abnormalities of the interatrial septum before TSP (thick septum, calcification, aneurysmal deformation, presence of a patent foramen ovale).
Finally, transthoracic echocardiographic guidance (TTE) could be helpful in experienced hands in case of difficulty when TOE is not available.
In the era of echo-guided TSP, it does not seem that there is a place for the levo phase of a right atrial injection to guide the procedure.
Procedure
The patient should be in strict horizontal position in order to facilitate orientation of TSP. TSP may however be performed in semi-supine position if there is no alternative as may be the case during PMC in patients with pulmonary oedema.
The sequential steps are as follows: (figure 2).
A pigtail catheter is positioned in the right coronary aortic sinus to locate the aorta and monitor aortic pressure. This can be omitted when echo guidance is used or after the early phase of training.
Procedural performance using fluoroscopic guidance. (A) a pigtail catheter may be positioned in the aortic root to mark the location of the aortic valve The dilator is advanced over a J-type guidewire into the superior vena cava. (B) The guide wire is removed and exchanged for the needle. (C) The dilator is pulled back from the superior vena cava to the fossa ovalis. (D) Antero-posterior fluoroscopic projection. The catheter and needle are now in the fossa, ovalis located inferiorly and medially to the pigtail catheter. (E) Right anterior oblique 30° fluoroscopic projection. The catheter and needle are inferior and posterior to the pigtail catheter.
Right femoral vein access eases TSP. Alternatively,left femoral approach can be used but TSP is more difficult and the pressure on the TSP catheter may be painful. In very rare cases where the transfemoral approach is not possible, TSP has been performed using a transjugular or transhepatic approach.22
A 0.035 or 0.032 inch J-tipped guidewire is positioned, up to the origin of the left innominate vein, in antero-posterior (AP) view avoiding the right atrial appendage.
After a cautious dilatation of the cutaneous entry puncture site, allowing for free movement, the catheter is advanced into the superior vena cava and the guidewire is removed.
After removal of the stylet, the TSP needle is connected to a pressure line, moved upwards close to the distal end of the dilator under fluoroscopy. If resistance occurs, the arrow located at the proximal part of the needle should be rotated until no resistance is felt. Some operators leave the stylet in place to reduce the risk that the needle will abrade or perforate the catheter. When the needle reaches the desired position the pressure is recorded.
During the following steps, the needle and the catheter should move together (figure 3).
The tip of the catheter is orientated initially pointing to the right shoulder of the patient in AP view. Then, both catheter and needle are pulled downwards and rotated counterclockwise until reaching the septum figure 4.
Moving the transseptal needle and the dilator. (A) The catheter and the needle should be moved as an assembly while maintaining the predetermined distance necessary to keep the needle tip inside the catheter. (B) The catheter and the needle are rotated such that the arrow points to 5 o’clock.
Necessary echocardiographic landmarks and definitions used for guidance of the transseptal puncture (transoesophageal echocardiography). Ao, aorta IVC, inferior vena cava; SAX, short axis view; SVC, superior vena cava.
Alternatively, the catheter can be initially directed towards the left shoulder. In such cases, the rotation is made clockwise and downwards with the perception of three sequential bumps at the level of the right atrium (RA)/superior vena cava junction; then the pulsatile ascending aorta and the passage over the limbus at the entrance of the fossa ovalis.
Whatever the approach, the proximal arrow of the TS catheter is located at 4 to 6 o’clock, looking from bottom to top. If the LA is severely enlarged, the arrow may be oriented towards 6 o’clock (figure 2).
The selection of an adequate puncture site varies depending on the imaging modality used for its guidance:
1. If the procedure is fluoroscopy guided:
In AP view, the adequate puncture site is mid-way between the pigtail catheter and the right atrial border in the horizontal axis and slightly lower than the tip of the pigtail catheter.
Additional views provide further guidance:
Right anterior oblique 30° with a target zone vertically in the middle of the line between the pigtail and the spina and below a horizontal line at the level of the pigtail. Some practitioners favour use of left anterior oblique and lateral views, which is less convenient as regards the manipulation of the C-arm to aid septal puncture.
2. If the TS is guided by echocardiography:
The different TOE views used are summarised in figure 4.
Three sequential two-dimensional TOE views will define the optimal target for TSP19 20: (1) long axis view (bicaval) at 90–120° for superior-inferior orientation; (2) short axis view at the base (30–50°) for AP orientation; (3) four-chamber view (0°) to determine the height above the mitral valve when performing transcatheter valve repair or implantation (figure 5).
Sequential steps of the echocardiographic guidance of transseptal puncture. 1) From superior to inferior in bicaval; 2) from anterior to posterior in short axis; 3) from high to low in four-chamber view.
The position of the TS catheter creates a ‘tenting’ of the septum into the left atrium, clockwise rotation of the needle allows for an anterior orientation. All movements should be of limited amplitude. The interventionist and the echocardiographist should work in harmony, one following the other, without simultaneous and uncoordinated movements.
Three-dimensional X-plane views facilitates TSP orientation (figure 6).
Guidance of transseptal puncture by transoesophageal echocardiography. (A) Three-dimensional transoesophageal echocardiography showing from left to right: tenting, puncturing and crossing of the interatrial septum. (B) Two-dimensional biplane transoesophageal imaging. Visualisation of the tenting of the septum towards the left atrium (arrow) in both simultaneous views: short axis view (left panel) and biplane view (right panel). LA, left atrium; RA, right atrium; AV, aortic valve.
If a specific interventional procedure is planned, the necessary time must be taken to perform the puncture at the specific site most appropriate for the given procedure. Whatever the mode of guidance before puncturing the septum, it is necessary to make a final assessment of the adequate positioning and the tactile feeling of the interatrial septum.
Only then, the needle is advanced. Entry into the LA is indicated by echography and by pressure recording. The lack of changes in pressure may be due to: 1) closure of the ‘robinet’ on the needle, or clotting inside the needle. In the latter case, blood should be gently aspirated. The presence of red blood confirms the good positioning; 2) a resistant septum may prevent penetration in the LA despite a correct positioning; 3) incorrect positioning will necessitate withdrawing in the inferior vena cava and repetition of the full manoeuver because the catheter should not be pushed upwards.
When the adequate position of the needle in the LA is confirmed the catheter may be advanced, in AP view, in order to better locate the borders of the LA.
Then the needle is pulled back the LA pressure is recorded (figure 7).
Pressure recording during transseptal puncture. On the lower left part: pressure curves recorded in the right atrium. On the lower right part: pressure curves recorded in the left atrium.
Afterwards, heparin (3000–5000 IU) is administered.
Specificities in transseptal puncture
Anatomic variations
Large right/left atrium
If the LA is severely enlarged the TSP should be performed in a slightly more inferior position avoiding a too posterior position which may result in a perforation into the pericardial space between the LA and RA. If the RA is very large bending the needle a few centimetres proximal to the tip will facilitate TSP.
Resistant septum
This may occur in redo intervention after cardiac surgery or after thoracic radiation.23 If crossing is still not possible despite forceful and continuous pressure, an inverted exchange angioplasty 0.014 guidewire should be inserted into the needle.w24 Alternatively, an electrosurgical cautery generator may be used to apply radiofrequency via the proximal part of the needle.25 If the needle can cross but not the catheter it may be helpful to introduce an exchange angioplasty 0.018 guidewire (Steelcore, Abbott Vascular) into the needle up to the superior pulmonary vein and use it as a support. Finally, the SafeSept TSP guidewire (Heart Medical Europe BV) may be a useful addition in such cases.
Specific interventional procedures
Percutaneous mitral commissurotomy
TSP during PMC does not require a specific puncture site even if TSP through a patent foramen ovale may render crossing of the mitral valve difficult. In the rare cases where TOE is used the optimal site for TSP is usually in the inferior and posterior part of the fossa ovale if the LA is severely enlarged.3
Percutaneous mitral valve repair or replacement
The available recommendations were mostly set for the performance of the MitraClip procedure.19 20
A suboptimal puncture site limits the movements of the device and results in technical failures. Patent foramen ovale should not be used to access the LA during structural heart intervention because its anterior location would not enable an easy and precise navigation of the devices towards the mitral valve.
To optimise the performance of these procedures, TSP must be performed in the superior-posterior part of the fossa ovalis and at a sufficient distance (height) from the mitral valve (figure 8). When using the MitraClip device in cases with primary MR, the TSP height should be 4–5 cm above the mitral annulus to allow the capture of prolapsed valves. Conversely, in secondary MR, the puncture site must be lower, approximately 3.5 cm above the annular plane or 4–4.5 cm above the coaptation of both leaflets in order to be able to advance the catheter more deeply into the LA because of valve tethering. An inadequate puncture site will lead to the following complications: aortic hugging if the puncture is too anterior—difficulties in crossing the mitral valve if TSP is too high, or in pulling back the clip if the puncture is too low; risk of perforation if TSP is too posterior. Higher (more superior) puncture is needed for medial jets while lower TSP is recommended in lateral jets.26
Target puncture sites for the MitraClip procedure and left atrial occlusion. ACP, Amplatzer cardiac plug; Ao, aorta; IVC, inferior vena cava; SVC, superior vena cava.
Other techniques of percutaneous treatment of mitral valve disease have been recently shown to be feasible and effective (figure 9).
Transcatheter mitral implantation (SAPIEN prosthesis) performed via a transseptal approach. (A) Transcatheter valve implantation in a dysfunctioning surgical bioprosthesis. (B) Transcatheter valve implantation in a failing annuloplasty ring. (C) Transcatheter implantation in severe mitral annular calcification.
The transseptal approach is becoming more popular over transapical or transatrial approaches in transcatheter mitral interventions (valve in a valve or valve in a ring or valve in massive annular calcification) because it is less invasive and recent data show its feasibility and effectiveness.5
Experience is even more limited for percutaneous direct mitral annuloplasty,6 where TSP is the only approach and where only a couple of cases of implantation of dedicated prostheses in native mitral valve were done using TSP because of the very large size of the current devices.7 There are no precise recommendations concerning TSP for these procedures. As a rule, TSP shares most of the characteristics of the MitraClip technique, that is, a superior and posterior puncture to allow for sufficient manoeuvrability in the LA and valve crossing.
Left atrial appendage closure
The transseptal approach is by far the most frequently used.27 The location of TSP is somewhat dependent on the particular characteristics of the device to be implanted in order to facilitate coaxial alignment and reduce the risk of complications and embolisation. When using the Watchman device the ideal location is in the middle portion of the posterior part of the fossa ovalis in order to allow a coaxial engagement of the appendage. The TS puncture is ideally slightly more anterior and inferior with the Amplatzer device (figure 8).
Paravalvular leak closure
Transseptal approach is also the most popular approach for the closure of paravalvular leak in patients with mitral prosthesis. A posterior and slightly superior TSP is best for medial leaks, although this is less important if the defect is at a distance from the septum.28
Complications
The incidence of complications of TSP is low if it is carefully performed.2 29 30
Failure occurs in 1%–2%, fatality is the exception (0%–0.08%). It is mostly due to heart perforation.
Heart perforation (0.1%–1.2%) related to TSP may concern the RA or LA or the aorta. It may be related to insufficient experience or difficult anatomy such as atrial enlargement or thoracic deformity. Its incidence varies from 1% to 4%. It should be feared when hypotension occurs during TSP and mandates the immediate performance of echocardiography to confirm the diagnosis. Puncture of the aorta by the needle is usually without consequences when it is identified immediately by pressure changes. Conversely, advancement of the catheter may lead to massive hemopericardium. The feasibility of using occluders to seal the puncture of the aorta has been reported.w31
In most cases, hemopericardium leading to tamponade can be managed by pericardiocentesis if it is due to the needle alone but may be more difficult to treat if the catheter has been advanced in an inappropriate location. Of note, the presence of even a mild-to-moderate pericardial effusion before the procedure should be described in the echo report to serve as a comparator if hemopericardium is suspected during the procedure.
Embolism due to TSP itself is rare (0.008%–0.4%).
ST-segment elevation in the inferior leads accompanied by a vagal reaction could occur after TSP. This results from a Bezold-Jarish-like reflex and can be treated using atropine32 or could be due to air embolism in the right coronary which points upwards in the supine position. During TSP itself the neural origin is more likely while air embolism is more frequently the cause when large devices are introduced into the LA.
Inferior vena cava perforation leading to retroperitoneal hematoma is very rare. It could result from the inadvertent puncture of the vessel by the needle through the catheter.
Transient atrial tachyarrhythmias are rare after TSP in isolation.
Persistent interatrial shunts are not observed after the performance of transseptal catheterisation in isolation, but could result from the introduction of large devices afterwards.
Training must address echocardiography
As is the case for all invasive procedures, there is a learning curve in TSP.2 29 Besides the technical skills, the training for TSP includes echocardiography and management of tamponade. Virtual training on simulators is a useful complement to clinical demonstrations in dedicated training sessions during interventional courses.33
Conclusions
TSP is now an important part of several interventional procedures in structural heart disease such as mitral valve interventions and left atrial appendage closure. It is a difficult procedure requiring specific expertise. However, when performed properly it is safe and reproducible.
Quantification of mitral gradient
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Key messages
In current practice, the use of transseptal puncture (TSP) has shifted from a diagnostic procedure to the first step before percutaneous mitral interventions such as percutaneous mitral commissurotomy—percutaneous mitral valve repair or replacement—paravalvular leak closure, or left atrial appendage closure.
The main contraindications of TSP are the presence of a thrombus/tumour in the left atrium/appendage or uncontrollable bleeding diathesis.
TSP may be guided by fluoroscopy only but most often echo-guided TSP is used for the following scenarios: safety for low volume operator—complex anatomy—and most importantly targeted/site-specific TSP for structural interventions. Transoesophageal echocardiography (TOE) is the most popular technique while intracardiac echocardiography can also be used in specific cases. Effective TOE guidance requires specific training and good understanding and collaboration between the interventionist and the echocardiographist.
When performed properly TSP is safe and reproducible. Heart perforation is rare and may be related to insufficient experience or difficult anatomy. Its suspicion mandates the immediate performance of echocardiography. In most cases, hemopericardium leading to tamponade can be managed by pericardiocentesis.
TSP is a difficult procedure requiring specific expertise. Besides specific technical skills, training must address echocardiography and management of tamponade. Virtual training on simulators is a useful method.
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References
Footnotes
Competing interests None declared.
Provenance and peer review Commissioned; externally peer reviewed.