Introduction
The transseptal puncture (TSP) is a critical step for left-sided structural heart interventions. Precise TSP sets the stage for a successful procedure; however, precision is often limited with current two-dimensional echocardiographic techniques. Additionally, cardiac computed tomography angiography is often utilized for preprocedural TSP planning; however, carrying out a three-dimensional plan with two-dimensional intraprocedural transesophageal echocardiography can be unreliable. In the current imaging vignette, we provide the basis for understanding three-dimensional interatrial septal anatomy, step-by-step guidance for performing TSP, variability in interatrial septal anatomy, and common pitfalls that may lead to suboptimal TSP .
Relevant anatomy of the interatrial septum (IAS) based on three-dimensional (3D) printing as it pertains to the transseptal puncture (TSP). IAS anatomy: 3D printed model of the IAS displayed from the left atrial (LA) perspective. The posterior wall of the LA has been cut off for visualization purposes. The fossa ovalis (FO) is represented in green. The access routes, typically the inferior vena cava (IVC) and occasionally the superior vena cava (SVC), are depicted. The target (mitral valve [MV]) is shown, with its anterior mitral leaflet (AML) and posterior mitral leaflet (PML), along with the medial commissure (MC). Other relevant structures, such as the aortic valve (AV), aorta, left atrial appendage (LAA), right upper pulmonary vein (RUPV), right lower pulmonary vein (RLPV), left upper pulmonary vein (LUPV), and left lower pulmonary vein (LLPV) are also displayed.
(a-b) Three-dimensional (3D) transesophageal echocardiography (TEE) and 3D printed left atrial view for the transseptal puncture (TSP). Left panel: 3D TEE of IAS. We use the LA perspective so that the access route (venae cavae [VC]), the crossing point (fossa ovalis [FO], circle in red), the landmark (aortic valve [AV]), and the target (mitral valve [MV]) are all displayed. The 3D image is oriented so that the MV leaflets (anterior mitral leaflet [AML], posterior mitral leaflet [PML]), as well as the medial commissure (MC), are at 6 o’clock while the AV is at 8 o’clock. The SVC and IVC are at the top. This 3D display shows the height relationship (double arrow) between the FO and the MV. Right panel: 3D-printed anatomy: 3D-printed anatomy is zoomed and oriented to provide a similar vantage point as that obtained on 3D TEE. Note a catheter in the noncoronary cusp (NCC) of AV, a commonly used fluoroscopic landmark to assist in TSP
Abbreviations: CS, coronary sinus; IAS, interatrial septum; IVC, inferior vena cava; SVC, superior vena cava.
Three-dimensional (3D) transesophageal echocardiography (TEE) and multiplanar reconstruction (MPR) views for the transseptal puncture (TSP). Left panel: 3D TEE of IAS, as in figure 2 a. Right panel: 3D MPR representation. The green plane is oriented along the access route (venae cavae [VC]) producing a typical 2D bicaval view, and the red plane is rotated to cross the AV to produce a 2D image with an anterior landmark. The cross hair is then used to follow the TSP needle. The lower images display the 3D rendering and its corresponding projection (blue plane). The location of the TSP needle is at the intersection of the red and green planes at the superior (and slightly anterior) aspect of the fossa ovalis. Videos 1 and 2 are provided to help better appreciate the anatomy depicted in the still images shown above
Abbreviations: AML, anterior mitral leaflet; AV, aortic valve; CS, coronary sinus; IAS, interatrial septum; IVC, inferior vena cava; MC, medial commissure; MV, mitral valve; PML, posterior mitral leaflet; SVC, superior vena cava.
