Paravalvular Leak: Access
Aortic or medial mitral PVLs can be approached by transfemoral access. The authors’ preference is to use a 0.035” wire, often a hydrophilic one (e.g. Terumo Glidewire, Terumo Medical Corporation, Somerset, NJ, USA) inside a 5 Fr diagnostic catheter (JR4 or MP). The wire crosses the leak and the catheter follows the wire. This wire is substituted for a stiff 0.035” wire (e.g. Amplatzer Extra Stiff Wire, St. Jude Corporation, Minneapolis MN, USA). The delivery system guide or sheath is then advanced over the stiff wire, which is then removed, and the device is placed in correct position. If more support is needed for the catheter or delivery system to cross the leak, a rail can be made (either by transseptal access and snare or by externalising the wire through transapical access). If the aortomitral curtain is crossed, it is often necessary to protect this from significant stress by covering a bare wire with a catheter at all times. For a medial mitral leak, a JR4 or IM catheter can be helpful.
Sometimes transseptal access is needed, either for mitral PVLs or difficult aortic PVLs. Any transseptal system should be used, and this should be performed under transoesophageal guidance. The authors recommend an inferior and midway between superior and posterior position for puncture for most leaks, although it is just as important to make sure the transseptal puncture is performed safely as it is to find a specific spot to cross the septum that will allow crossing of the leak. For difficult aortic PVLs, the leak is crossed during retrograde femoral approach and a rail is formed by snaring the wire in the left atrium. For transseptal access, heparin 10,000 units should be administered.
When a mitral PVL cannot be crossed through other methods or if there are mechanical heart valves in both aortic and mitral positions, transapical access can be considered. In addition to echocardiographic/fluoroscopic visualisation to determine the position of the ventricular apex, it is also important to perform concomitant coronary angiography to avoid the coronary arteries. A sheath (often 4 Fr) is delivered and heparin is given. A device is often used to close the entry site (e.g. Amplatzer PDA Occluder, St. Jude Corporation). The authhors recommend this as a third and last option, as there is an increased risk of complications from tamponade, hemothorax or puncture of a coronary artery. Follow-up TTE and chest X-ray are highly recommended at 24 hours after procedure/discharge.
Paravalvular Leaks: Device Selection
There are only a few devices designed specifically for PVLs, thus other devices have often been used. The ideal device has the appropriate size and shape for the leak and does not interfere with the valve leaflets. Furthermore, it does not interfere with other vital structures, such as the coronary ostia in the case of aortic valves or left ventricular outflow tract in the case of mitral valves. Optimally, only one device is needed.
The device size is dependent on measurements from echocardiogram (TEE and 3D whenever possible). Angiography helps in the case of aortic PVL when this can be seen next to the valve. Some may use external catheter size to approximate leak size, but this is also dependent on calcification and tortuosity, which can cause difficulty in a catheter’s ability to cross the leak. The authors follow this general algorithm: for a small cylindrical leak, an Amplatzer Vascular Plug (AVP) II or PDA Occluder may be best; for an oval or crescentic leak, the AVP III is more ideal; if the leak is small or has significant angulation, an AVP IV is better as it is more flexible.
Recently, the Occlutech PLD (Helsingborg, Sweden) device has obtained CE mark approval. There are two devices, one square and one rectangular, both made of nitinol braided mesh. Waist size is chosen similar to the defect size, and this ranges from 3 to 7 mm with circular waist for the square device (requiring 5–7 Fr sheath) and from 4 x 2 to 12 x 5 mm for the rectangular device (requiring 5–8 Fr sheath).10