Do you want MICROEMBOLISM-FREE procedures in aneurysm coiling?
A brief introduction to ‘stop-and-aspirate-out’ technique
내용: 울산의대 서울아산병원 영상의학과 이덕희
Script: Prof. LEE, Deok Hee. Dept of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
자료: 서울아산병원 영상의학과 신경중재 니드팀
Sources: Neurointervention NIDD, Asan Medical Center
Literatures
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For microembolism-free neurovascular procedures
Fighting against any (thrombo)embolic event is one of our main concerns for safe neurovascular procedures.
In a sense, thromboembolic complication could be an inevitable fate of neuro-endovascular procedures since we are playing within the cerebral vasculature supplying the sophisticated and delicate brain.
Due to the current limitations in the devices and techniques we are using and adopting, embolism-free procedure could be challenging even in experienced interventionists.
Ironically, during the procedure, overt thrombosis or thromboembolism which can cause overt infarction might not be a big problem for the experienced interventionists since the phenomenon could easily be noted during the procedure and can be managed with parenteral administration of the IIbIIIa inhibitors.
What I would like to emphasize in this video presentation is, so called, microembolisms.
Microembolisms are quite common in our daily practice.
The incidence in the literature ranges from 20% to 90%, usually around 50-60% when counting cases with only one or two DWI high signal spots.
Fortunately, those DWI hits are asymptomatic and leave virtually no clinical consequence in the long run. However, we do have the risk of symptomatic ischemia depending on the location of those hits.
Besides the potential risk of cerebral ischemia, unclear late effect of those high signal hits, it is uncomfortable to observe them on the DWI obtained the next day even in the case with otherwise perfect procedure.
Then, what are the sources of the microembolic lesions.
Let’s name them…
Thromboembolism associated with catheterization
Atheroembolism from the arch
Embolic device-related thrombosis (coils, stents, and others)
Air bubbles from the flushing solution or from the devices
Denuded hydrophilic coating materials or other foreign bodies
Blood clots either formed during manipulation of the devices or formed due to the interaction of the device surface with the blood and blood vessels.
That’s why we anticoagulate the patients and put them on antiplatelets.
We used to be obscessed with drug resistance issue.
Anti-thrombotic measures are very important, however, I am a little skeptical on the role of modified antiplatelet regimen on the reduction of the microembolism.
It is said that the fine fragments of the fibers released from the linen drapes could be the nidus of the thrombus. We need to try to avoid injecting any red or even pink-colored liquid through the catheters.
Air bubbles are also well-known potential emboli and we are trained to perform air bubble free procedures.
Several years ago, we reported introduction of significant amount of air bubble during detachable coil delivery, especially in particular type of coils.
Interestingly, other than the Oxygen and hydrogen formed during electrolytic detachment, most of the air bubbles were noted right after removal of the pusher wire.
Similar findings were seen with some microguidewires.
After observing these ugly pictures full of air bubbles, we changed our microcatheter handling technique from the usual continuous saline flushing method to stop-and-aspirate-out technique.
After applying this new technique, we could reduce the microembolism problem significantly as we reported.
We have thought that reduction of those air bubbles might help reduce the problem until we came across several stunning reports on the observation of device coating embolism.
With this we could extend our hypothesis on the beneficial mechanism of the proposed stop-and-aspirate-out technique for the microembolism-free procedure not just minimizing air embolism but also minimizing embolization of the liberated hydrophilic coating materials.
It becomes our steadfast belief because the microembolic dots become less and less after we switched our main microcatheter to another one. There could be some difference in the stability of the surface coating.
From now on, we are presenting our current effort especially in the endovascular aneurysm embolization.
