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Dr. Igor Pagiola
Interventional Neuroradiologist
INRAD - Instituto de Radiologia HCFMUSP
São Paulo, Brésil
Once again, we are at the stage where trials and clinical experience in the endovascular treatment of the acute phase of stroke are about to break paradigms.
We saw this before when the time needed to begin performing femoral punctures was thought to be limited to 6 hours while now we have studies demonstrating benefits up to 24 hours. There are even some reported cases demonstrating good outcomes even after more than 24 hours. This shifted the “time” paradigm to a “viable tissue” paradigm.
Another big change we are experiencing which is increasingly being studied is in the management of large ischemic core strokes.
If we go back to previous studies published in early 2015, we see that the inclusion of most patients was for large vessel occlusions (LVO).
With the increase in the performance of mechanical thrombectomy, we started to face two interesting situations:
Also, we need to remember that 25-40% of strokes are caused by MeVO or DiVO (distal vessel occlusion) and that intravenous thrombolysis fails to achieve recanalization in 50% of these cases.
Many doubts have arisen concerning these two scenarios:
But, we know that there are many INR services today who have begun performing thrombectomy of these vessels, demonstrating that it is possible to treat these types of patients.
Additionally, there is a need to define how we will classify a MeVO.
Will it be by:
At present, we are seeing the emergence of devices for performing MeVO mechanical thrombectomies. Regardless of the technique employed (ADAPT or stent retriever) the devices have become more navigable and compatible with smaller vessels. One of the more current examples is the Solitaire X 3mm for performing MeVO thrombectomies.
Even though many services perform this type of treatment, in order to change the guidelines themselves we need randomized clinical trials – the key approach to achieve certainty in our daily practice.
Another point to raise is the matter of anesthesia. According to Dr. Demetrius Lopes "The optimal anesthesia approach for MeVO stroke intervention is currently unknown. MeVO mechanical thrombectomy involves smaller vessels and may be more difficult to assess in uncooperative patients. General anesthesia as a first choice should be considered based on these factors: location of occlusion (challenging anatomy), older patient age, operator experience, and availability of a skilled anesthesia team. Otherwise, starting the procedure with local anesthesia or conscious sedation and convert to general if necessary seems to be also a reasonable approach until more data is available."
These will be just some of the subjects that we will be discussing in this edition of the LINNC newsletter focusing on MeVO.
And looking at the recent past where mechanical thrombectomy destroyed all paradigms, soon I hope to be able to say that as LVO was in 2015, MeVO will be the new broken paradigm, allowing me to announce, sometime in the next two years:
“MeVO is the new LVO for mechanical thrombectomy.”
