Percutaneous Repair of Paravalvular Leaks

Preprocedural Echocardiography

For most patients, the diagnosis of valvular regurgitation and PVL is made by TTE. It should be noted, however, that because of shielding from prosthetic valves, regurgitation may not be well visualized on the TTE. Furthermore the eccentric nature of most PVLs makes diagnosis of regurgitation severity more difficult, because routine parameters such as size of the color-flow jet or the proximal isovolumic surface area may be significantly underestimated. Therefore further imaging either with TEE or angiography is recommended in cases when the clinical presentation and TTE are incongruent.

Performance of a percutaneous PVL closure requires precise definition of the leak origin in order to properly direct wires and devices to the area. Preprocedural echocardiography is therefore important not only to define the degree of PVL, but also to identify the exact origin of the regurgitant jet and allow for procedural planning before the patient’s arrival in the catheterization lab or hybrid operating room.

Localization of Mitral Paravalvular Leak

For the sake of consistency in nomenclature, the mitral valve (MV) is viewed as a clock face, and leak origin defined by the position on the clock ( Figure 12–1 ). Using TTE, the parasternal short-axis image is useful, displaying the MV as a clock face that allows an easy definition of the PVL origin ( Figure 12–2 ). In a large surgical series, the most common location for mitral PVL was anteromedial (between hours 10 and 11) and posterolateral (between hours 5 and 6). Similar analysis of a percutaneous series revealed the most common mitral PVLs between 10 and 2 o’clock (45%) and between 6 and 10 o’clock (37%).

When using TEE, localizing the PVL requires a reconstruction of the clock face in the mind of the operator. Figure 12–3 demonstrates the clock-face orientation of the MV with TEE angles listed around the periphery of the valve showing which parts of the MV are interrogated at each angle. Movement of the TEE probe cranial and caudal with anteflexion or retroflexion of the imaging crystal cuts the valve at planes parallel to those listed.

An example of PVL localization by TEE is given in Figure 12–4 : In A, the leak origin is shown in the 120 - degree view, with the leak in the anterior portion of the MVR; in B, the leak origin is shown in the 30 - degree aortic short-axis view, just medial to the aortic valve (AV) (i.e., next to the left coronary cusp). The ultrasound beam at each of these TEE angles is applied to the MV clock-face view in C, with localization of the PVL at the intersection. D confirms the location where an Amplatzer ventricular septal occluder device (St. Jude Medical, St. Paul, Minn.) was subsequently placed.

Localization of Aortic Paravalvular Leak

Position along the perimeter of the aortic valve can also be referenced to a clock face, as shown in Figure 12–1 . In a large series examining PVL closure, aortic leaks most commonly presented at the 7 to 11 o’clock position (46%), followed by the 11 to 3 o’clock position (36%). Alternatively, operators may choose to identify the origin of the PVL with respect to the native cusp location (i.e., right, left, and noncoronary cusps). This is useful for procedural guidance and for assessing risk of coronary impingement with a device. Whereas the long-axis TTE and TEE views are helpful in defining the anteroposterior relationship of the leak, the short-axis view is most helpful in defining the leak with respect to the cusps ( Figure 12–5 ). This relationship allows a simple translation to the fluoroscopic projection of the aortic root ( Figure 12–6 ).

Procedural Echocardiography

Guidance of the percutaneous PVL closure procedure can be performed using TEE and/or ICE. The authors perform all PVL procedures using only conscious sedation and local anesthetic, and therefore try to minimize the duration of TEE use, instead favoring ICE to direct the procedure until TEE is absolutely necessary ( Figure 12–7 ). Generally, the TEE probe is placed after crossing the leak with a wire and before crossing it with a delivery sheath. In certain situations, ICE is ineffective at properly visualizing the mitral PVL and TEE guidance is necessary for crossing the leak. This is especially true in cases of lateral PVL, where the ICE catheter is furthest away from the leak. ICE is routinely used for transseptal (TS) puncture of the interatrial septum (IAS), and therefore it is already in place for guidance during mitral PVL procedures that are performed via TS puncture. In patients requiring tricuspid or aortic PVL, an extra femoral venous sheath is placed to introduce the ICE catheter for procedural guidance.

TEE is also integral to the PVL procedure for wire/catheter guidance, evaluation of procedural success and need for additional device(s), and assessment of complications (such as valve impingement by the device). Since ICE and TEE are 2D imaging modalities, the entirety of wires and catheters may not be seen in the left atrium (LA) if the devices are off-axis to the imaging plane. Echocardiographic guidance of the equipment may therefore require constant adjustment of the ICE and/or TEE. On the other hand, real-time 3D TEE provides excellent image resolution and guidance of wires and devices to the site of PVL with minimal manipulation of the imaging probe ( Figure 12–8 ). Because not all probes and TEE machines are capable of real-time 3D imaging, it is important to assure that the proper equipment is on hand before commencing the procedure.

Procedural Fluoroscopy and Angiography

Fluoroscopic imaging is routine in catheterization lab procedures. Interventional cardiologists have become accustomed to manipulating wires, catheters, and other devices while observing their movements on the fluoroscopic screen. In the case of mechanical or bioprosthetic valve replacements, an additional degree of guidance is provided by the prosthetic valve/ring. In order to cross the PVL, orthogonal fluoroscopic views are necessary to assure appropriate wire placement in all planes. This is most easily done using a biplane system; in labs without biplane fluoroscopy, repetitively moving the C -arm to each view can be cumbersome but should be done. This is especially important after device deployment in the paravalvular space to assure that prosthetic leaflet motion is not hindered. For mitral PVL, the 30-degree right anterior oblique and left anterior oblique (LAO) caudal (spider) projections are most useful for device placement. For aortic PVL, a shallow LAO projection often provides adequate imaging.

In addition to echocardiography, angiography may be helpful in defining the location of a PVL for procedural guidance ( Figure 12–9 ). However, as the patients who need PVL closure are often sick with numerous comorbidities including chronic kidney disease, angiography is not often used.

Procedural Computed Tomography–Fluoroscopy Fusion Imaging

Fluoroscopy provides a 2D image of 3D structures. The operator must integrate the 2D and 3D images obtained echocardiographically into his or her mental picture of the intracardiac space to properly guide wires, catheters, and devices to the PVL for percutaneous closure under fluoroscopic guidance. In order to bridge this 2D-to-3D gap, technologies have been developed to overlay information taken from CT onto the real-time fluoroscopic image.

A thorough description of the fusion process has been previously published (see reference ), and an overview is given in Figure 12–10 . In brief, after the initial identification of PVL origin using TTE and/or TEE, a mark is made on the preprocedural CT scan of the PVL. Markings of the proposed TS puncture location are also made to aid guidance of the Brockenbrough needle. CT markings are made of the prosthetic valve, the trachea, and/or other structures to provide assurance of proper image overlay. Upon the patient’s arrival to the cardiac catheterization lab, a rotational CT-like image (Syngo DynaCT, Siemens Healthcare, Forchheim, Germany) is obtained to establish the patient orientation on the table. The preprocedural CT is then registered to the procedural DynaCT (3D-3D fusion), and the CT markings can be overlaid onto the real-time fluoroscopic images. This process is quite helpful in directing wires through the PVL, anecdotally reducing procedural time, radiation dose, and TEE duration.

Access Site/Approach for Paravalvular Leak Closure

In the case of mitral PVL, the operator must decide on the approach that will allow access to the leak and that provides enough support to deliver the bulky delivery sheath and device to the area. Potential routes for mitral PVL closure include:

• 1.

  TS Approach: TS puncture and antegrade access to the mitral PVL is from the LA via a femoral venous sheath. If there is inadequate support to place a delivery sheath with a wire passed into the left ventricle, the wire can be advanced to the descending aorta ( Figure 12–11 , A ) (and also snared via the femoral artery if necessary) or snared via a transapical (TA) sheath ( Figure 12–11 , B ). TA snaring may be useful if snaring from the descending aorta results in impingement upon the prosthetic leaflets and hemodynamic compromise or in the presence of a mechanical aortic valve.

  

• 2.

  Femoral Artery Approach: A guiding catheter is advanced across the AV to the left ventricle and the PVL is wired retrograde. This may be accomplished with a Glidewire (Terumo Medical, Somerset, NJ) or even a 0.014-inch coronary wire that can often be “blown through” the mitral PVL. The retrograde wire is then snared via TS puncture and brought to a femoral venous sheath; devices are delivered in an antegrade fashion across the PVL via the femoral vein ( Figure 12–11 , C ). This approach is not feasible if the patient has a mechanical AVR.

• 3.

  TA Approach: Direct retrograde wiring is from the left ventricle via TA sheath placement. Devices may be delivered retrograde via a delivery sheath placed in the left ventricular (LV) apex ( Figure 12–11 , D ) or in an antegrade fashion after snaring the wire via TS puncture (in order to minimize the LA apical sheath size) ( Figure 12–11 , E ).

The choice of the above approaches must be made on a patient-specific basis. The TS approach is usually favored over the TA approach in order to avoid direct LA apical trauma and the potential complications of sheath insertion therein. Generally, a PVL that is near the anterior and lateral aspects of the MV can be wired via the TS approach.

Leaks that are posterior and medial may be more difficult to engage from the LA because of the acute angles that are presented after TS puncture; therefore the apical or retrograde aortic approaches may be preferred. This is not to say that posterior/medial leaks cannot be fixed via TS puncture, but operators should be aware that failure to cross the PVL antegrade does not imply complete failure of the percutaneous approach in a given patient.

In some rare circumstances, a patient’s IAS may be so calcified that TS puncture or advancement of a sheath across the IAS is not possible. Consideration may be given to the application of electrocautery energy to the Brockenbrough TS needle to facilitate puncture. If the TS approach is impossible, TA access or a retrograde femoral artery approach should be considered.

For patients with aortic PVL, the retrograde femoral artery approach is most commonly used. When this is not successful, consideration may be given to the TS or TA approaches. Patients with concomitant mechanical MVR are not candidates for the TS approach. Care must also be taken with the TS approach to avoid creating a taut loop of wire from the IAS to the aorta that can cause MV leaflet impingement (and hence MR) or tear the MV apparatus.

Sheath size is dictated by the choice of approach and expected devices to be delivered (discussed in the following paragraphs). Another consideration is whether multiple devices need to be delivered simultaneously. In this case, a large femoral sheath (i.e., 16F) may be placed to allow placement of two large delivery sheaths across the IAS at the same time.

Transseptal Approach to Mitral Paravalvular Leak Closure

The TS puncture is described in Chapter 4 . With respect to PVL closure, however, the specific location of TS puncture should be carefully planned to allow easiest access to the leak. For leaks that are lateral, the usual puncture high on the IAS is reasonable. However, for patients with a more medial leak, a lower and more posterior TS puncture allows more direct/coaxial access to the PVL ( Figure 12–12 ). After dilation of the IAS, we prefer to advance an Agilis NxT steerable guide catheter (St. Jude Medical, St. Paul, Minn.) to the LA. The Agilis is an 8.5F (internal diameter) catheter with a deflectable tip and is available with three distal curl options: (1) small (16.8 mm), (2) medium (22.4 mm), and (3) large (50.0 mm). The authors generally use the medium curve for most applications, though the presence of a severely dilated LA may necessitate the large curl, or a significantly acute angle from the IAS to the leak (in the case of medial PVLs) may require a small curl. Some operators prefer to use a curved-tip guiding catheter such as the JR4, Berenstein, or Hockey Stick instead of the Agilis.

A 120-cm 4F angled glide catheter is then advanced via the Agilis into the LA. The telescopic combination of the angled glide catheter tip and articulation of the Agilis provides a wide range of directions to direct a wire across the leak. A 0.035-inch stiff-angled Glidewire (SAG) is the first choice, but a hydrophilic 0.014-inch coronary wire may be used if the SAG is unsuccessful. Once the wire is across the leak, it is advanced further into the descending aorta. At this point the wire may be snared via femoral artery access if necessary, though simply advancing it to the distal aorta usually provides enough purchase and support for the procedure. If the operator chooses not to advance the wire to the aorta (i.e., in a patient with mechanical AVR), the angled Glide catheter can be advanced to the left ventricle and used to exchange the SAG wire for a stiffer support wire such as an Amplatz Extra Stiff (Cook Medical, Bloomington, Ind.) wire or Lunderquist wire (Cook Medical) if necessary. Care should be taken to make a broad curve on these wires to avoid trauma/perforation of the left ventricle.

The combination of the Agilis and Glide catheter is then removed. A delivery sheath is then advanced over the SAG that is in place across the PVL. Delivery sheath size is based on the size of the device needed. The authors usually use the 8F Amplatzer TorqVue 45-Degree Delivery System (St. Jude Medical). Alternatively, a 6F multipurpose guide catheter can be used, depending on the device that will be delivered to the leak. Once the TorqVue is advanced to the left ventricle, the SAG is removed and the occluder device is loaded into the sheath. The LV disc is then deployed and apposed to the LV side of the leak. The LA side of the device is then exposed. Careful evaluation should be made fluoroscopically and by echo for leak persistence and/or impingement of the device(s) on the prosthetic valve (discussed later). The TS approach is illustrated in Figure 12–13 .

In situations where one device does not adequately close the PVL, two (or more) devices can be deployed. This is illustrated in Figure 12–14 . Briefly, after crossing the leak with an SAG wire, the Agilis or other catheter (such as a 7F multipurpose guide) is advanced over the wire to the left ventricle and a second SAG wire is advanced to the aorta. Each wire can then accommodate a delivery sheath if necessary. If the operators prefer to deploy both devices simultaneously to assess the degree of PVL closure, a large enough femoral venous sheath (14F to 20F) is required to accommodate both delivery systems. For instance, two 6F coronary guides can be advanced across the defect to allow simultaneous deployment of two Amplatzer vascular plugs. Alternatively, operators may choose to advance an 0.014-inch wire via the TorqVue delivery sheath before advancing the occluder device, keeping wire access to the leak in case there is need for a second device ( Figure 12–15 ).