Interest in transseptal puncture has surged with the development of structural interventions for the left side of the heart. Francesco Maisano provides an update on its changing role in modern interventional cardiology.
The transseptal puncture (TP) technique was developed in the 1950s by Ross et al as a diagnostic tool to investigate patient haemodynamics before cardiac surgery. However, as Doppler echocardiography became established as the main method of interpreting haemodynamics, diagnostic applications were rapidly abandoned, and transseptal puncture was no longer used much by most interventional cardiologists, although electrophysiologists continued to routinely perform it for atrial fibrillation ablation.
The advent of left-sided catheter-based therapies, and the introduction into clinical practice of several left heart structural interventions, has reawakened an interest in learning and retraining in transseptal puncture. Transseptal puncture has become a necessary step for approaching the left atrium.
Mitral valve balloon commissurotomy was the first structural procedure that required transseptal puncture and, later, the first cases of transcatheter aortic valve implantation (TAVI) were performed via an antegrade transvenous–transseptal approach, before smaller delivery systems became available. Mitral valve interventions and left atrial appendage (LAA) occlusions have also become available and are being progressively adopted in many centres.
Reaching a critical puncture
These new procedures have introduced a new requirement for transseptal puncture—particularly in mitral interventions as the location of the puncture within the fossa ovalis plays a critical role in the efficiency of the procedures and their probability of success. For this reason, transseptal puncture for mitral interventions is routinely performed using echocardiographic guidance, in addition to fluoroscopy and continuous pressure measurement.
Depending on the type of intervention, the patient anatomy and the type of device, different locations can be preferable: for example, inferior punctures for LAA occlusion, posterior punctures for leaflet repair, inferior–posterior punctures for mitral valve-in-valve, and so on. Under 2D and 3D echo-guidance, the exact location of the puncture can usually be well identified. Three standard echo views are used to determine the coordinates of the puncture: the bi-caval view is used to determine the position of the puncture on the superior–inferior axis, the short axis view at the base is used to check the position on the anterior–posterior axis, and the four-chamber view to measure the height (distance) from the mitral valve annulus. In addition, 3D images can provide further information about the relative position of the puncture in relation to the target of therapy.
Precise and safe
With echo guidance, the puncture is not only more precise, but it is also safer. When punctures are confined within the membranous portion of the fossa ovalis, the risk of tamponade is very low, and further manipulation of the catheters is safe and fast. Intracardiac echocardiograpy has been also used to guide transseptal punctures, and the availability of 3D probes for intracardiac echocardiography may expand its application further. Pre-procedural planning tools are available to simulate the position of the transseptal puncture from a CT-scan, and fusion imaging can be used to guide the procedure by integrating live fluoroscopy and echocardiography, as well as the prerecorded overlays of the CT scan, eventually incorporating markers from the planning tools.
Novel TSP catheters
Mirroring the field of structural interventions, which has rapidly developed with the introduction of new devices and techniques, there has recently been a drive to develop novel transseptal catheters to better fulfill the requirements of modern interventions. Although the original transseptal system still in use in most labs does not differ much from the original Mullin’s sheath and Brockenbrough needle, several innovations are now available. These include different catheter shapes and structures, safer needles, steerable needles and catheters, and radiofrequency catheters to address complex anatomies (for example, post-cardiotomy and floppy septum). The most recent new technologies include the TSP crosser (Transseptal Solution), a steerable transseptal catheter with a localisation/stabilisation tool to identify and then navigate on the fossa; the FlexPoint (Indian Wells Medical), a steerable needle to simplify the procedure; and the Kapsus catheter (Bavaria Medizin Technologien GmBH), to assist and control the site of puncture within the fossa (Figure 1).
Embrace the new
The modern structural interventionalist should embrace most of the new technologies and techniques to tackle the vast variability of patient anatomies and procedural requirements. Learning transseptal techniques is once again becoming a “must-do” and there are several opportunities to get trained. At our institution, we run several transseptal courses, including hands-on training with high fidelity physical and computer simulators, and similar short versions of these courses are available at major conferences, like Transcatheter Valve Therapies (TVT), Transcatheter Cardiovascular Therapeutics (TCT), PCR, and London Valves.
Now is the time to learn the basics as well as the advanced skills necessary to perform transseptal puncture in left heart structural interventions.
Francesco Maisano is at the Department of Cardiovascular Surgery, University Hospital Zurich, Zurich, Switzerland.