This is the most common approach for mitral PVL closure and will be described in detail with the most common possible variants. After adequate infusion of local anesthetics, the femoral vein is accessed and cannulated to perform echo-guided interatrial septum puncture, choosing the puncture site as previously reported. During the whole procedure, the activated clotting time should be frequently checked and maintained above 250–300 s by heparin administration. Sometimes the use of radiofrequency or electrocautery devices is needed to facilitate the passage through a fibrous or altered septum. Additionally, to safely pass hardened septums and avoid any damage to the left atrial walls, the use of dedicated guidewires able to assume J-shape after crossing, such as the SafeSept transseptal guidewire (Pressure Products Medical Supplies Inc, San Pedro, CA), may be useful and allow more gentle maneuvers. The septum is then dilated as usual and a telescopic system is advanced through it: most often it is helpful to use a steerable device as the Agilis NxT Introducer (St. Jude Medical, St. Paul, MN), an 8.5 French sheath available in three distal curve sizes to adapt best for pointing toward the PVL site. If the operator prefers, an ordinary angiographic guiding catheter may be directly introduced without the sheath: the choice is based on the anatomy, but usually Judkins right, Hockey stick, or internal mammary are best suited. The advantage of using a steerable sheath consists in the possibility of maneuvering complex telescopic setups to achieve three-dimensional orientation of the devices to fine-direct the selected guidewire across the defect. In fact, catheters of decreasing size can be telescoped together and rotated/advanced independently: typically a 6-Fr 100 cm multipurpose guiding with another 5-Fr longer (125 cm) multipurpose diagnostic or an angled catheter of choice inside [28]. Sometimes, the use of an angled 4-Fr glide catheter (120 cm by Terumo Medical) may be of help in particular situations such as posteromedial PVLs [29]. Anyway, the use of such an equipment usually allows complete probing of the mitral valvular ring.

Of course, the next procedural step consists in crossing the true lumen of the identified PVL with a guidewire in order to gain access to the left ventricular side and proceed. An angled, extra-stiff, and exchange long 0.035″ idrophilic guide (e.g., Glidewire by Terumo Medical) is therefore advanced through the defect with fine rotation by dedicated torquer, while available imaging modalities (RAO/LAO angio views, TEE, or ICE) are carefully monitored to avoid intravalvular crossing. Once ensured correct positioning, the guidewire is advanced deeply into the left ventricle to form a loop avoiding any wall damage, pointing toward the outflow tract, and entering the ascending aorta where it will be finally advanced down to the descending thoracic part in order to the minimize the risk of displacement/loose of position. In some difficult cases, especially when the PVL is particularly small or fissure-like, the use of a regular 0.014″ coronary guidewire may be an option.

After crossing the PVL with the wire, the operator needs to advance the catheter(s) of his telescopic system through the defect: this maneuver should be performed very cautiously due to the risk of losing the position or damaging the structures as relevant force is needed to be accomplished. Therefore, at this point, the need for higher support should be determined, and additional techniques may be used to gain it. Most commonly, an arteriovenous loop is created by accessing the contralateral femoral artery and advancing a snare to capture the wire parked in the descending aorta for externalization and fixing. This technique usually guarantees extremely high support for the rest of the procedure.

The next step depends on the choice of the occluder device(s) to be used; in fact, while smaller devices like the Amplatzer Vascular Plug II (AVP II; St. Jude Medical, St. Paul, MN) up to 12 mm can pass quite easily though a 6-Fr guiding catheter, other devices of larger dimensions usually require catheters of higher diameters. The force required to advance a 6-Fr catheter through the defect may be a good indicator for the size of the device to start with, selecting smaller ones for difficult crossings. On the contrary, when the defect is large, the common choice is to advance a dedicated sheath like a 9- or 10-Fr Amplatzer TorqVue delivery into the ventricle for bulky occluders. If necessary, the interatrial septum may be further dilated prior crossing with this larger stuff.

The preferred method for defect reduction or closure should be selected and preplanned on the basis of the PVL morphological characteristics, whenever possible. In fact, when the PVL is small and oblong or crescentic, it is often more advisable to account for the use of multiple smaller devices, while round and bigger defects are commonly best addressed with single larger occluders [7]. Figure 11.2 describes the characteristics of the most commonly used commercial devices for PVL closure. Ductal, septal, and muscular VSD occluders from Amplatzer may also be chosen when appropriate, but due to the higher stiffness of their nitinol structure and bigger sizes, these may be more prone to develop postprocedural hemolysis [14]. Of note, as none of these devices are specifically designed for PVL closure to date, and due to the great anatomical variety of periprosthetic defects, the use of this material remains off-label, and great care should be taken when planning their use.

The next phase is the release of the selected device across the mitral PVL: with the guiding catheter or sheath inside the left ventricle, the distal portion of the occluder is advanced and opens into the cavity. Then the whole system is very carefully retracted against the mitral valvular ring, and the operator starts a controlled release of the device by gently pushing the device while continuing the retraction of the sheath. Collaboration with the echocardiographer is crucial to identify interference with the prosthesis at this stage, when it is possible to readvance the sheath and retry with a different orientation. If manipulation is not sufficient for avoiding valve dysfunction, a different or smaller occluder may be selected and tried. When satisfied with the behavior of the device, the release can be completed proceeding with the retraction of the sheath, and final detach from the delivery system may be accomplished. Of course, the interaction between the occluder type and the PVL anatomy determines the shape that it will assume when released: in particular, the proximal portion may open and extend in the atrial structure or may remain compressed within the PVL channel. In either case, the device stability and adequate occlusion should be carefully assessed prior to final release.

If more than one device are needed, several techniques may be used to avoid losing the position into the left ventricle through the leak. In particular, when a multiple occluder procedure was previously planned, a multiple-guidewire approach may be chosen: a 20-Fr venous femoral introducer is needed to limit access bleeding, and two (or even three) 0.032″ extra-stiff guidewires are advanced through the crossing guiding catheter (typically the 6-Fr multipurpose) that is then carefully removed after wire placement into the left ventricle or aorta if possible. Afterward, two independent telescopic systems (again, typically a 5-Fr diagnostic into a 6-Fr guiding catheters) are mounted onto the wires and then advanced through the leak to permit simultaneous device delivery.

When multiple devices are not planned or the defect is not big enough for the above-described simultaneous-delivery technique, a sequential approach may be used. This time when the hydrophilic wire is in place in the descending aorta, a 0.032″ or 0.035″ stiff wire is advanced into the left ventricle through the guiding catheter. Then, another sheath (typically an 8-Fr Cook Flexor Shuttle Sheath by Cook Medical) is placed into the LV and permits delivery of the first device. The sheath is then removed leaving the occluder attached to its delivery cable and readvanced through the extra-stiff wire, allowing for repeated sequential occluder delivery. Alternatively, an arteriovenous loop can be obtained as previously described, and the tension and support offered by the hydrophilic externalized wire may be controlled by a second operator. Like in the previous technique, a sheath is needed and this time advanced directly onto the arteriovenous loop wire to deliver in sequence the desired number of occluders [7, 30]. For sequential delivery techniques, the need for smaller catheters as the leak gets reduced by the devices should be taken into account. Caution must be used when manipulating the externalized wire for more support, as damages on the vessels, prosthesis impingement, or anatomy distortion may occur and complicate the procedure. A useful tip is to remember controlling the aortic pressure shape, as excessive wire tension induces aortic regurgitation and therefore lowers diastolic pressure: of course, this condition should be eliminated as soon as possible by releasing the tension on the wire. A step-by-step description of the usual transseptal antegrade technique is detailed in Fig. 11.3.