I. Antiplatelet Premedication: The correctly chosen premedication is essential. PLAVIX (minimum 600mg) should ideally be administered during eight days prior to procedure (75mg per day). However, a loading dose of 600mg of PLAVIX may be administered the day before the intervention (although this is not preferable). In conjunction with PLAVIX, Aspirin therapy should be administered at a rate of 100mg per day. These are general guidelines and should be adapted to the status of the patient. II. SILK size selection 1. Diameter SILK s conformability is enhanced if the stent is open to its maximum diameter due to the fact that this facilitates deployment. Consequently, the selected SILK diameter should be the smallest compatible with the artery. Refer to the compatibility interval indicated on the label : For vessel from to Example: SILK4,0x should be selected (SILK4,0 are suitable for arteries of diameter 3.5 to 4.25) Ø4.2mm Ø4.2mm NB: SILK4,5 is also compatible (suitable for vessels with diameter 4.0 4.75), although obtaining optimal conformability is more difficult due to its greater diameter. If the diameter of the artery distal to the lesion is smaller than the proximal one (sometimes due to a compression effect of the aneurysm on the artery itself), the SILK should be selected using the smaller (distal) diameter, as explained above. Always ensure that the proximal diameter (the biggest) is no larger (it can be the same) than the diameter of the SILK when Fully Open (check the label). Example Ø4.0mm Ø3.5mm SILK3,5x should be selected Suitable for vessel with diameters from 3.0 to 3.75 Fully Open diameter : 4.0 Exception: If the difference in diameters is too significant, the selected SILK should have a Fully Open diameter equal to the proximal (greater) diameter. The distal part of the SILK will then probably be oversized and particular attention should be paid during its deployment (as the distal oversizing may affect conformability) Example Ø4.5mm Ø3.0mm SILK4,0x should be selected For vessel of 3.5 min & 4.25 max Fully Open diameter : 4.5mm Note: Para-opthalmic aneurysms are usually treated with SILK4,0x Aneurysms proximal to opthalmic artery are usually treated with SILK4,5x Page 1 / 8
2. Length SILK shortens considerably when deployed. The following approximate shortening should be considered: 1/2 1/2 SILK length inside delivery catheter= L KT Nominal Ø length L NOM = L KT /2 Fully open length L FO = L NOM /2 SILK should extend from both ends of the aneurysm neck: 1.5 times the artery diameter as a minimum. However, if possible, it is preferable to leave 10mm of SILK extending from both ends of the aneurysm. Placement in wide neck aneurysms will result in increased shortening of the SILK as the expansion will be greater in the unconstrained neck of aneurysm. This must be taken into account by selecting a SILK longer than the normal intracranial stent that would otherwise have been selected. 1.5xØ artery = minimum for safety 10 mm = recommended Ø4.5mm Ø3.0mm In this type of case, select: SILK4,0x25 or SILK4,0x30 Note The selected SILK is usually 5 to 10 mm longer than the LEO+ which could also be selected for the same case. Unique Indication for fusiform Aneurysm In the case of a fusiform aneurysm, the SILK will shorten considerably as it deploys to its maximum diameter through the major part of its length. Consequently, the SILK should be selected according to the Fully Open length that is marked on the label. Note: A simple rule can generally be applied to determine the SILK size: Length of the Fully Open SILK = length of fusiform aneurysm plus 5 to 10 mm Example: In this case, select: SILK4,5x40 Fully Open length = 22 (approx. 15+5) Never plan to lengthen a SILK during its implantation by exerting tension (even slightly) on the SILK through the fusiform part of the aneurysm, as it will lead to the SILK jumping into the aneurysm. Due to the precise nature of correct size selection, it is difficult to size the SILK prior to the angiography performed during the placement procedure. For this reason BALT has developed the STARTERSET concept, which provides a panel of SILK sizes along with the size selected prior to the procedure. Thanks to the STARTERSET, it is possible to select a different size SILK at the time of implantation to ensure a safe and effective placement. Contact your BALT distributor for more information on STARTERSET. Page 2 / 8
III. Procedure 1. Access Perfect control of push and pull movements as well as a perfect stability of the catheters is mandatory whilst deploying a SILK. Therefore, it is important to take the time to build a stable coaxial platform to ensure one-to-one control of the practitioner s manipulations. We strongly advise that: For access to the anterior circulation a long (80cm) 6F introducer should be positioned in the common carotid or in the proximal internal carotid. Balt IVA6F80 is ideal for this purpose, although Terumo s Destination is also suitable. The sheath should not be longer than 80 cm (in particular a 90cm sheath is not ideal), as it will unnecessarily protrude outside the patient and may prevent the other catheters from being placed distally enough to deliver the Silk. A Guide catheter is used to enable a very distal placement with high stability. Balt FARGO is designed for this purpose. The Penumbra Neuron is also suitable for this purpose. It should be noted that FARGO has a greater resistance to distal kinking and has a bigger internal diameter, thus making contrast injection (for Roadmapping) easier. Additionally, FARGO can be easily placed more distally, in the carotid siphon or up to the basilar artery providing optimal support and security during SILK deployment. Page 3 / 8
2. Device preparation A SILK set comprises: 1 Delivery catheter Vasco+21 1 Y-connector with a side-arm adaptor ANRYV 1 SILK prosthesis mounted on its pusher, all packaged in an introducing tube VASCO+21 micro-catheter is pre-shaped with a Multi-Purpose distal curve (MP: approx 45 angle). It is generally not useful to change the curve. In the packaging the distal curve is protected by a blister. Do not manipulate this blister. Incorrect opening or detachment can damage or kink the catheter s distal end which may result in SILK blockage and catheter impaction during placement). Avoiding handling the distal part of the VASCO+21, pull firmly on the proximal hub to remove it from the protective tube to release the catheter. Its distal pre-shaped tip will withdraw from the protective blister unobstructed. Do not flush the catheter before doing this. Protection blister (do not manipulate) Take the catheter out by pulling on the hub without manipulating the catheter s distal tip Catheter hub It is essential to fully flush of the delivery catheter VASCO+21 and to check that the valve of the Y-connector does not leak. If blood backflows inside the catheter and saturates the constrained SILK, the SILK may be glued by fibrin (even with Plavix, Aspirin and Heparin) and will not open once deployed outside the catheter. HINTS & TIPS: - Some users soak SILK with a small quantity of pure heparin before flushing the introducer with normal saline solution. The efficacy of this practice is not proven however, and is the interventionalist s decision. - Many Interventionalists administer an anti-spasm drug through the guide-catheter s flushing port (3mg of Nimodipin for 1 litre). Page 4 / 8
3. Navigation and passage of SILK VASCO+21 is preferably used with a.014 guide wire. The VASCO+21 should be placed very distal to the placement site (for example, do not hesitate to mount Vasco+21 in the MCA in the case of a paraopthalmic aneurysm) and pull the guide wire out. (Fig.1) Fig.1 Vasco+21 Once done, straighten VASCO+21 as much as possible in order to eliminate or lessen the curves. This will facilitate the SILK mounting and control during deployment. (Fig.2) FARGO Fig.2 Straightening the Vasco will bring the FARGO up Partially insert the SILK introducer into the Y-connector. Increase the pressure on the perfusion bag to a maximum. Allow the saline solution to run out of the proximal end of the introducer for 30 seconds minimum, pulling and pushing the pusher so that the SILK moves backwards and forwards over a maximum of 1 cm until any existing air bubbles in the SILK disappear. The distal end of the pusher must remain inside the introducer throughout this manipulation. Advance the introducer until it reaches full contact with the VASCO+21 hub (the contact should be complete, but do not exert high pressure) and tighten the Y-connector firmly to avoid any movement between the introducer and the hub. Note: the passage of the SILK produces considerable distraction forces between the hub and the introducer, and if the latter shifts this poses 3 risks: - SILK can deploy inside the VASCO+21 hub and the device is lost - SILK shifts on its delivery wire, which considerably increases friction inside the catheter and SILK can become jammed in the catheter. - SILK s distal end may be damaged which can result in the failure of the distal portion of the prothesis to expand during deployment. Continue advancing SILK to the distal tip of VASCO+21, checking for the absence any leakage of the perfusion fluid at the Y-connector. Until the SILK is detached, never torque the delivery wire (torquing will lead to delivery wire s failure and the SILK can be lost) Page 5 / 8
4. Deployment Push out 15 mm of the delivery wire (the distal radiopaque end). (Fig.3) Pull VASCO+21 creating a fix-point on the delivery wire (like with Neuroform and Enterprise) until SILK comes out and deploys to approximately 1 cm. (Fig.4). This manipulation ensures that SILK does not move distally which can result in the wire struts of the SILK damaging the vessel wall. Using this technique, SILK shortens during deployment and the distal part draws back thus avoiding any traumatic movement. If this technique is not utilised, it generally leads to a slight annulus spasm at SILK distal end, which could cause reduction of flow. It is also possible that the distal segment of the SILK fails to expand if this technique is not observed. 15mm Fig.3 SILK proximal marker Fig.4 Do not push the delivery wire forward while unsheathing 1cm of SILK by pulling on the Vasco Once the SILK is deployed by approximately 1 cm, position the distal tip simultaneously pulling on the catheter and on the delivery wire. (Fig.5) Fig.5 Fig.6 Continue deploying the SILK by pulling back on the catheter and compensate with delivery wire advancement. Check that the delivery wire is advancing freely in the distal vasculature. (Fig.6) The procedure should be carried out delicately: Excessive pushing or pulling can adversely affect deployment. If necessary you may gently manipulate or play with the catheter, by pushing it forwards and pulling it backwards until the SILK has opened correctly. The added stability afforded by the FARGO guide catheter and the IVA6F80 long introducer facilitates this action. It is worth training with a model DEMO SILK, which BALT representatives use for demonstration. Example of wrong deployment: In this case, too much compression on the system is not allowing the SILK to deploy correctly. The problem is solved by pulling on the whole system (catheter and wire) Page 6 / 8
SILK is detached when its proximal marker overpasses the distal marker of VASCO+21. Before SILK is detached, make sure that it is correctly deployed through its entire length and its artery wall apposition is complete. Fig.7 Vasco+ marker Once detached, the SILK proximal tip might be not fully deployed (particularly in a curve). The most effective technique is to push the proximal end with VASCO+21 and make it open. In plain terms this technique is referred to as a kick in the ass. (Fig.7bis) SILK proximal marker Pushing the SILK with the Vasco+ can improve its deployment and wall apposition Vasco Vasco Fig.7bis It is crucial to take time to move the VASCO+21 over the delivery wire inside the SILK in order to position it very distally (sometimes the delivery wire should be straightened, to prevent VASCO+21 bumping into the proximal end of the SILK). During this procedure the catheter will press against the inside wall of the SILK and improve its apposition to the artery wall. Next, remove the delivery wire and straighten VASCO+21 by applying slow and gentle traction: thus it will press against the opposite walls of the SILK and ensure a good apposition. This technique is known as the Internal Massage. (Fig.8) Fig.8 Before removing VASCO+21, perform all the necessary angiographic assessments. Whilst VASCO+21 remains in position inside the stent, it is still possible to: - place a second SILK (using the same VASCO+21), i.e. to do a Telescopic SILK. - place a remodelling balloon, using an exchange guidewire through VASCO+21 (ECLIPSE with STEEL12D300: wire.012 /300cm long). This extra step is very rarely required if all the steps described above are correctly executed. After thoroughly checking that every aspect of SILK deployment is satisfactory, the VASCO+21 can be removed. Carefully study the hemodynamic changes. A phenomenon has been observed in which arteries disappear due to an alteration of pressure balances with communicating arteries in which there is no thrombus, nor which have any associated clinical consequences. It may also be observed that the SILK appears to be filled in, although a simple passage of a micro-guidewire makes the artery refill, without any thrombotic phenomenon being observed. We are currently unable to explain these apparent filling defects. Page 7 / 8
IV. Post-procedure NOTE: The following information reflects current knowledge in April 2009 and should be adapted to each patient in accordance with their individual condition and to take into account any further knowledge. If no contraindications are present, low-dose heparin (500U/h) can be administrated to the patient for twentyfour hours. Post-medication: PLAVIX 75 mg/day and ASPIRIN 100mg/day. The current consensus is to administer PLAVIX for a minimum of 3 months, and for 6 months if communicating arteries stem from the aneurismal sac covered by SILK and to administer ASPIRIN for 1 year. It is important that full communication and understanding be established with the patient to ensure this regimen is adhered to; several complications have been observed due to a premature ceasing of this premedication by the patient. In the case of treatment for a giant aneurysm, it is commonly observed that the aneurysm s size increases during the thrombosis period following SILK placement, probably due to an inflammatory response. This phenomenon could be a cause of: - Headaches - worsening symptoms (particularly visual) - arterial stenosis due to the compression exerted by the mass effect of the aneurysm (in particular when the artery is constrained against a bone structure) The phenomena may persist over a period of 3 to 8 days, generally during the 2 weeks following the procedure, or following the discontinuation of post-medication with PLAVIX. Corticoids can be administered in order to limit the consequences of the inflammatory response. We hope that these Tips & Tricks will enable you to work with SILK in a safe and effective manner. However, we strongly recommend that the first five SILK cases are monitored by a proctor specialising in SILK. BALT has several proctors and is at your service to coordinate their attendance for supervising early SILK cases. Page 8 / 8