Fig. 5.1
AmplatzerTM Vascular Plug (AVP; St. Jude Medical, Inc., Plymouth, MN). (a) AVP II and (b) AVP III. These devices are made of self-expanding finely braided nitinol wire mesh. A device is selected according to the dimensions and shape of the defect to be occluded. The AVP II is more suited to circular defects, whereas the oblong shape of the AVP III fits well in the more slit like and crescentic holes (Amplatzer and St. Jude Medical are trademarks of St. Jude Medical, Inc. or its related companies. Reproduced with permission of St. Jude Medical, © 2016. All rights reserved)
Fig. 5.2
Anterograde, transseptal approach to close a mitral paravalvular leak. (a) A transseptal sheath has been placed in position across the inter-atrial septum, and a left Judkins coronary diagnostic catheter is introduced. (b) A Terumo TM guide wire (Terumo Europe NV) is guide wire is advanced through the Judkins catheter and manipulated so as to cross the defect into the left ventricle (LV). (c) The Judkins catheter is advanced over the wire to follow it into the LV. (d) The Terumo TM wire is removed and replaced with an Amplatz TM extra stiff wire (Cook Medical), to provide a more rigid rail. (e) A delivery sheath is advanced over the stiff wire across the defect. (f) The closure device is introduced through the delivery sheath. (g) The distal disc of the closure device is advanced out of the sheath, and as it does so the nitinol frame conforms to its original unconstrained shape. (h) The device is pulled back so that the distal disc sits on the ventricular side of the defect. As the delivery sheath is pulled further back the proximal disc is released from constraint and also assumes its original shape on the atrial side of the defect. Careful assessment is then carried out to check that the device is securely in position and that the discs are not obstructing the mitral valve leaflets. The delivery cable is subsequently detached from the device and the equipment withdrawn leaving the closure device in place
Fig. 5.3
Alternative approaches to mitral paravalvular leak closure. (a) An example of a retrograde approach. A wire has been passed retrogradely from the femoral artery to the aortic root, and across the aortic valve to the LV. A Judkins shaped or extra back-up shaped catheter is used to help steer the wire back through the paravalvular defect and into the left atrium. A transseptal catheter is passed from the femoral vein to the right atrium and across the inter-atrial septum to the left atrium. This is used to introduce a snare to capture the retrograde wire. A ‘circuit’ can then be created from the femoral artery, through the defect and back out to the femoral vein. This circuit is used to introduce a delivery sheath and deploy a device in the defect. (b) A transapical approach. The apex of the LV is punctured through the anterior chest wall, and a wire introduced into the ventricle. From here it is directed retrogradely across the defect into the left atrium. A delivery catheter is then placed over this wire and an occlusion device delivered to the defect. If the defect is large, the delivery sheath required may be of a large diameter. To avoid creating a large puncture in the LV apex, an anterograde approach might be favoured. For this method the wire is snared in the left atrium, and a circuit created. The large delivery sheath can then be introduced through the femoral vein and the occluder delivered in an anterograde fashion
Fig. 5.4
Retrograde approach to aortic paravalvular leak closure. (a) A Judkins diagnostic catheter is introduced to the aortic root. (b) A Terumo TM wire is used through this catheter to cross the defect. (c) The catheter follows the wire into the LV. (d) The Terumo TM wire is switched for the more supportive Amplatz TM extra stiff wire. (e) The catheter is withdrawn. (f) A delivery sheath is introduced on the stiff wire, across the defect. (g) The closure device is advanced attached to the delivery cable. (h) The distal disc is released to adopt its normal configuration. (i) The distal disc is pulled back against the LV side of the defect. (j) The proximal disc is released. (k) Checks are made to ensure device stability and that there is no interference with valve function, and then it is released from its delivery cable
The therapeutic endpoint should be determined before initiating the procedure. If the procedure is being done primarily for treatment of heart failure, any marked reduction in regurgitant volume is likely to help the patient. However, if the procedure is done primarily to treat haemolysis, complete obliteration of regurgitation is usually necessary for efficacy. Important considerations clearly include determining which specific leak is responsible for the haemolysis. Should residual regurgitation be present, color flow Doppler assessment can be extremely difficult because of splaying of the jet through the residual leak and around the first device. Measuring left atrial pressure does not usually help because pressure typically does not decrease immediately.
Tilting-disk valves may be pulled shut during device deployment, which can be recognised immediately if the fluoroscopic planes are set up correctly. Valve obstruction may be relieved by reversing the deployment manoeuvre and pushing the delivery catheter and device back into the mid left ventricle (LV). Devices may also obstruct prosthetic valve leaflets during systole and prevent valve closure. In this scenario, frequently the only sign is an abrupt increase in valvular regurgitation that is greater than the normal closing volume. Rarely, a device may tilt after deployment and block the prosthetic leaflet. If this occurs, two options are available. The first is to use a long, flexible, bioptome through the steerable left atrial sheath. The second option is to snare the distal portion of the device and pull it anterograde through the defect. Failure of these manoeuvres will necessitate surgery. Stroke or transient ischemic attacks can result from systemic thromboembolism, either peri- or post-procedure and are related to transition of anticoagulation regimens. Therefore meticulous attention to catheter flushing and adequate heparinisation are mandatory.
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