Fig. 19.1
Guidewire tip has been advanced into an MCA branch to enable ICA stenting. During manipulation, perforation of MCA occurred. In panel (a) the tip appears to be within the vessel. However, after the wire was retracted, contrast extravasation was noted on angiography, indicative of vessel perforation (b). The area of interest, where the wire tip had been, is encircled
Ensure there is not too much energy in the wire or catheter. If needed, gently pull the wire or catheter back, to remove any redundancy or slack. When the slack is adequately removed, the loop just proximal to the tip will be seen to pulsate and only a fraction more retraction will be required to straighten out the system with the tip withdrawing only slightly. If done carefully, access will not be lost.
What to Do Once It Has Occurred
An awake patient will complain of sudden, severe, and persistent headache, possibly with stiff neck. While cerebral angioplasty in an awake patient may cause pain, it is transient and dissipates when the balloon is deflated. Persistence of pain is indicative of rupture. Depending upon the severity of rupture, there may be a decline in the level of consciousness. In an anesthetized (or awake) patient, the monitors may show a sudden increase in blood pressure due to the rise in ICP. There may be concomitant bradycardia.
ABC’s first. Ensure the patient has a protected airway and remains well oxygenated. Use an ambu bag if needed. Have the patient intubated, if the airway is unprotected.
Stop and reverse therapeutic heparinization, including administration of protamine 1 mg per 100 units of heparin (maximum 50 mg). Usually, protamine is administered over 10–30 min to prevent idiosyncratic hypotension and anaphylactoid symptoms. However, in endovascular emergencies such as this one, anticoagulation must be immediately reversed by rapid IV bolus of protamine (10 mg over 1–3 min). A preloaded syringe of 50 mg should remain available at all times during most endovascular procedures, to enable rapid bolus administration in case of an emergency.
Consider:
NovoSeven™ 90 µg/kg IV bolus over 2–5 min.
FFP.
Immediate steps to control ICP.
If EVD in place, open to drain CSF.
Ensure head midline and venous return is not compromised.
Consider anti-Trendelenberg position.
Mannitol 1 gm/kg infused rapidly within 20 min.
May need to direct others to perform these maneuvers while you take steps to address the complication.
Endovascular maneuvers.
Maintain wire (0.014″) access to the injured vessel. If access is lost, attempt to rapidly re-access the perforated vessel with wire. If successful, consider:
Placement of a covered stent, to exclude the site of perforation. If the rupture occurred following deployment of a stent, place a second stent overlapping with the first to cover the perforation site.
If the perforation was caused at site of balloon angioplasty during procedure, exchange for a balloon 1 mm smaller in size and inflate.
If necessary, sacrifice the involved vessel using coils. With this approach, e.g., in the M2 segment of MCA as in Fig. 19.1, the complication of stroke is accepted with the aim of saving the patient’s life.
Neurosurgical maneuvers.
Decompressive craniotomy, and if feasible, evacuation of the clot.
Displacement/Embolization of Detached Coil from Aneurysm
This may occur if the coil:
Is smaller than the circumference of the aneurysmal sac in which case, it may embolize out with the arterial pulsations.
Is displaced by the repositioning or retraction of microcatheter.
Was still partially in the microcatheter when detached.
Was partially deployed and then retrieval attempted due to unsatisfactory deployment. If the coil inadvertently entangled with previously detached coils, it may pull out coil/coil mass from the aneurysm.
Prevention
Select a coil with circumference equal to or slightly greater than the aneurysm circumference for the framing coil. Downsize gradually, as needed, for additional coils.
Before detachment, observe the coil using live fluoroscopy. If it visibly pulsates, the chances of it being displaced out of the aneurysm are significant. Consider removing it and replacing it with a larger size coil.
Pay particular attention to ensure that the marker on the coil has crossed the proximal marker of the microcatheter to form a ‘T’ before detaching it.
What to Do Once It Has Occurred
If the coil has not displaced yet, but is threatening to do so, consider rapidly deploying additional coils to trap the offensive coil within the aneurysm.
If the coil has already displaced out of the aneurysm then the options are as follows:
Assess if the coil can be retrieved endovascularly using snares or merci retriever. To do so, place a rapid transit catheter (Cordis, Miami, FL) adjacent to the coil by advancing it over microguidewire (e.g., Synchro 14).
Remove the microguidewire and advance an alligator retrieval device (ev3, Plymouth, MN) through the microcatheter, until it reaches the tip of the microcatheter.
Holding the microcatheter, advance the retrieval device slightly forward. This will result in opening of the jaws of the device (visualized fluoroscopically by separation of radiopaque markers). Attempt to engage the proximal tip of the coil. Once the coil appears to be engaged, advance the microcatheter slightly forward while holding the alligator device in position, to close the jaws of the device.
Maintaining slight tension on the alligator device, withdraw it and the microcatheter together as a unit completely through the guide catheter and the patient’s body.
Sometimes, it may not be possible to withdraw the coil fragment completely. Even relocating it to less critical regions compared to intracranial vasculature, e.g., branches of ECA or peripheral vasculature of lower extremity may be more acceptable.
Also, bear in mind the possibility of accidentally embolizing the coil to an even more critical location, causing the patient greater harm (Fig. 19.2a–g).
Fig. 19.2
a An anterior communicating aneurysm, which was treated by coiling. During the intervention, one of the coils detached prematurely resulting in a considerable length remaining outside the aneurysm and extending down into the ICA (b). An alligator snare was used in an attempt to grab and retrieve the errant coil. Initially, the result was rostral displacement of the coil (c and d). Eventually, the coil was successfully ensnared and retracted. However, control of the coil was lost in the femoral artery (e, arrow). The coil is better seen just inferior to femoral head on fluoroscopy image (f, arrow). The patient did not manifest any lower extremity deficit consequent to the inadvertent coil deposition. Post-intervention cerebral angiography demonstrated complete occlusion of the Acom aneurysm (g). There was no filling defect, vessel cutoff, or any other abnormality consequent to the earlier misadventure with the coil. After completion of intervention, vascular surgery was consulted and the errant coil was removed from the femoral artery surgically
If it is not possible to endovascularly remove the coil, a strong consideration should be given to trapping it against the wall of the vessel by using a stent as follows:
Prowler Select Plus (0.021″ inner diameter, 5 cm distal length) (Cordis Neurovascular, Miami, FL).
Transend microwire (0.014, or 0.010).
Enterprise Vascular Reconstruction Device and Delivery System (Cordis Neurovascular, Miami, FL).
The unconstrained diameter of Enterprise stent is 4.5 mm. The available lengths (in mm) are 14, 22, 28, and 37, respectively.
Technique
The guide catheter should be positioned as close to the site of stenting as safely possible to ensure stability of the system during deployment. However, it should be at least a cm (usually more) away from the site of stent placement to enable smooth deployment.
Our preferred stent is Enterprise stent, which is deployed as follows:
Prepare a Prowler Select Plus microcatheter by attaching it to an RHV and removing the shaping wire from its distal tip.
Connect the RHV to a three-way stopcock that is connected to a continuously running flush of heparinized saline.
Ensure the microcatheter (and all catheters introduced into the patient) are free of air bubbles.
Using fluoroscopy and roadmapping, advance a Prowler Select Plus microcatheter over a microwire and cross the site of stent deployment.
Select the appropriate Enterprise stent and inspect the package to rule out any damage or breakage in sterility.
Using sterile precautions, remove the dispenser hoop from the package and place it on the sterile equipment table.
Free the delivery wire from the clip on the dispenser hoop.
Grasp the introducer and the delivery wire at the point where it exits from the dispenser hoop. This will prevent stent movement.
While holding the introducer and delivery wire, remove the system from the dispenser hoop. Make sure the stent is not partially deployed.
Ensure that the wire is not kinked and the introducer is undamaged.
Do not attempt to shape the distal end of the delivery wire.
Loosen the RHV of the microcatheter.
Insert the distal end of the introducer partially into the RHV.
Tighten the RHV around the introducer.
Press the wings of the pediatric transducer on the tubing leading to the microcatheter, which will result in increased flow. Confirm that the fluid is exiting from the proximal end of the introducer. Purge the device until the saline flush has evacuated out any air from the system.
Slightly loosen the RHV and grasping the introducer and wire together, advance the introducer until it completely engages the hub of the microcatheter.
Advance the delivery wire to transfer the stent from the introducer into the microcatheter. Do not torque the wire at any point.
Continue to advance the wire until the marker at 150 cm (from the distal wire tip) enters the RHV.
Loosen the RHV and remove the introducer off the wire.
Using fluoroscopy, observe the stent as it is advanced toward the microcatheter tip.
Align the stent positioning marker on the wire across the coil.
Once positioned, confirm the following markers are visible on fluoroscopy in the following sequence distal to proximal:
- i.
Distal tip of catheter.
- ii.
Distal marker on delivery wire.
- iii.
Distal stent markers (appear as a single marker, until stent is deployed).
- iv.
Stent positioning marker on delivery wire (this is in the mid-region of the stent.
- v.
Small marker indicating the extent to which the stent can be partially deployed and still recaptured (manufacturer recommends that recapture be performed only once).
- vi.
Proximal stent markers (appear as a single marker, until stent is deployed).
- vii.
Proximal marker on delivery wire.
- viii.
Proximal marker on the catheter (the position of this marker is not crucial provided the above are positioned adequately).
- i.
Also ensure the distal tip of the guide catheter is visible and the catheter is stable, so it will not inadvertently collapse during stent deployment.
Remove all slack from the system.
Ensure the microcatheter RHV has been loosened.
Slowly retract the microcatheter under live fluoro while holding the delivery wire stable, so that it does not move. The marker on the tip of the microcatheter will be noted to move proximally toward the markers on the delivery wire.
As the microcatheter is retracted further, the distal stent markers will separate indicating the deployment of distal stent.Related posts:
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