Complications during giant cavernous aneurysm treatment:

Diagnostic work-up before any intervention:

• MRI to evaluate mass effect and thrombosis
• DSA:
  • Always inject contralateral ICA
  • Inject posterior circulation
  • Always perform balloon occlusion test:
    • Rely on angiodynamics if symmetrical venous phase or 1-2 seconds maximum delay in the venous phase (awake)
    • If the venous delay is less than or equal to equal 2 seconds  – perform a full 30-minute neurologic examination
    • If done under general anaesthesia and the delay in venous phase is around 2 seconds it is reasonable to wake up the patient and do a full neurologic examination for 30 min
    • Think about increasing the sensibility of the test by reducing the blood pressure by 20mmHg if you have doubts

Complications management:

Suboptimal opening of the flow-diverter that needs balloon angioplasty:

• If there is no good distal anchoring you may risk foreshortening and the distal part of the stent may slide inside the aneurysm and you may lose access to the distal ICA. Never underestimate the need for good anchoring in giant cavernous aneurysm cases
  • Before angioplasty – carefully navigate the guidewire of the angioplasty balloon in the distal MCA;
  • Always use dual lumen balloons, in case of foreshortening you may still keep distal access;
  • Consider using 3-meter wires, in case of complications you may already have an exchange wire in place and you don’t need to navigate your balloon inside the MCA in order to perform a wire exchange
  • If you have a 2-meter wire you need to navigate your dual lumen balloon inside the MCA, if it is not tracking properly try to advance the intermediate catheter inside the proximal portion of your flow-diverter. Using a smaller intermediate catheter 5-Fr may be recommended for this kind of maneuver.

• Once the microcatheter is safely deployed inside the MCA consider bridging with another flow-diverter with a very long and good distal anchoring
• If positive occlusion test before the procedure – consider closing the carotid as an option if catheterization is difficult

Exchange maneuver during neurointerventional procedures:

• Very dangerous due to high risk of bleeding due to perforation
• Never do an intracranial exchange maneuver alone;
• If patient vital metrics change do a control run – look for late phase and perforation;
• Always know where your wire is!
• Ask the second operator to always follow the distal tip of the wire and to alarm you if any improper movement is spotted;
• Use a tiny J-shape for your guidewire;
• Perform the exchange slowly;
• Always keep the wire in a safe position, keep the biplane continuously because guide-wire tip movement may not be visible just in one projection, and stay in the M3 segment;
• Two moments when the risk of perforation with the wire are high: 1) around M1-M2 due to insular branches which you don’t see – keep the wire in place; 2) when you pass your microcatheter and your microguidewire in M2-M3 may be pushed to M4;
• Use guitar string technique: pinch the microcatheter that is removed at the level of the valve in order to ensure that the second operator who performs the exchange does not pull it easily out of the patient;
• Once you get the wire close your valve as tightly as possible and control that the wire is not moving during complete microcatheter removal;
• The exchange microcatheter may block in the ophthalmic and you may use a 0.10 microguidewire in the 0.27 in order to reduce the gap in this case;

Perforation during exchange maneuver during neurointerventional procedures:

• Completely devote all the attention towards the bleeding – this is what will kill the patient;
• Don’t worry about the aneurysm when you have active bleeding;
• Reverse heparin;
• Ask someone to compress the carotid at the level of the neck (there is a rationale for using balloon guide catheters in cases in which you are concerned about a risk of bleeding);
• Rapidly mount a dual lumen balloon and inflate it for at least 5 minutes;
• After control do unsubtracted images and control with the two projections;
• Perform Cone Beam CT;

Options if bleeding stopped:

• Stop the procedure or occlude the carotid
• The problem is the haemorrhage, be concerned about the haemorrhage
• Stop the procedure rationale:
  • Even if bleeding stopped – risk of delayed bleeding due to antiplatelet medication on board;
  • Leave the stent as it is – with the option that you can come back and see what you can do in a second time;
  • Do not occlude initially the carotid, even if you theoretically have this option because with SAH you have high ICP and risk of vasospasm which makes your previous balloon occlusion test result less reliable (totally different situation);
  • You can also think if feasible of removing the first stent and performing a stent-ectomy: this may reduce embolic risk;
  • If you have to place an extraventricular drain, but you are on double antiplatelet therapy think about posing a lumbar drain which is much more safe in this setting;

• Carotid occlusion rationale:
  • Think about carotid sacrifice, with dual antiplatelet and heparin on board you expose the patients to future risks like the need to pose an extraventricular drain or surgery if bleeding recommences;
  • Risk is that the initial balloon occlusion test is not helping due to marginal perfusion and future vasospasm;
  • No risk of distal embolization from the stent;
  • Less risk of subsequent bleeding because you can stop antiplatelet medication;
  • Stentectomy is possible but it is adding complexity to a really straight-forward procedure in which you already had several complications;
  • Use bigger coils if available for carotid occlusion;