Report by Rajiv Advani MD PhD FESO, Norway Twitter: @rajeroni
The first day of the ESO-WSO 2020 Congress and the first Live Q&A session focused on Controversies in Thrombectomy.
The session focussed on three key controversies in the field of mechanical thrombectomy (MT); using perfusion imaging to guide extended time window thrombectomy, Drip and Ship versus Mothership models and acute intracranial stenting as rescue therapy in the setting of primary EVT failure.
Do We Need Perfusion Imaging to Guide MT In Extended Time Window – YES
Prof. Gotz Thomalla from Germany started off by presenting the pros for using perfusion imaging in extended time window MT. Right off the bat we saw that perfusion based selection was the driving force for the DAWN and DIFFUSE trials. These trials included patients with a significant penumbra visualised on perfusion imaging. Prof. Thomalla continued by pointing out the inter-observer variability of the ASPECTS score arguing that this wasn’t the most reliable method of verifying viable penumbra. The use of Perfusion imaging augments the identification of viable penumbra and the use of Tmax amongst others can show non-viable tissue. Tmax > 6 seconds is red and red tissue is dead tissue!
Do We Need Perfusion Imaging to Guide MT In Extended Time Window – NO
Prof. Mayank Goyal from Canada presented the cons for the use of perfusion based imaging in extended window MT. Prof. Goyal pointed out that the time window for extended window MT was arbitrary and wasn’t based on the physiological progression of an ischemic stroke. Rather, it is based on study design and therefore using 6 hours as an absolute cut off to warrant the use of perfusion imaging isn’t well founded. Furthermore, we heard that perfusion imaging and its interpretation is time consuming and often leads to more neurons dying. Patient selection in extended window trials favoured those with good collaterals and therefore didn’t always reflect the real-world situations. Patients with an equivalent infarct size treated using MT and those treated with best medical treatment alone favour the use of MT. Avoiding perfusion imaging leads to more simplified decision making; decision making takes time and neurons die!
Patients with Severe Stroke Should be Directly Transferred to an Interventional Center (Bypassing Smaller Non-Interventional Centers) – YES
Prof. Blanca Fuentes from Spain guided us through the pros of direct EMS transfer to Mothership centres. This leave no patient behind approach guarantees that most if not all patients are considered for MT. Additionally, this approach saves not only time (and brain), but also resources in terms of personnel and costs. Avoiding going through two hospitals also has great benefits in the times of a pandemic. Prof. Fuentes went on to describe the direct transfer routines in Madrid and the use of the MDIRECT scale which led to better functional outcomes and reduced mortality as a result of LVO stroke. When highly specialised treatment is involved patients should be directly transferred!
Patients with Severe Stroke Should be Directly Transferred to an Interventional Center (Bypassing Smaller Non-Interventional Centers) – NO
Prof. Marios Psychogios from Switzerland presented the cons of direct transfer to the Mothership centre. When a primary treatment centre is bypassed the time to intravenous thrombolysis is inevitably longer and leads to a treatment delay. The role of IVT is still important especially considering that prehospital stroke scales have a low specificity and sensitivity for LVO stroke. Prof. Psychogios then went on to discuss the use of Mobile Stroke Units (MSU) which save time and can facilitate transport to MT centres. Another interesting concept is that of moving the interventionist to the patient and therefore reducing the time to recanalization. Prof. Psychogios specified that this should always be done in a fast, German sports car – the Drip and Drive model. Time is key, work fast and consider Drip and Drive!
Acute Intracranial Stenting Should be Performed as Rescue Treatment in Failed Recanalization – YES
Prof. Chapot from Germany discussed the pros of acute intracranial stenting in the setting of a failed primary MT. We heard how the expectations of stroke treatment physicians had changed over the last decade; it is now firmly expected that MT reopens an occluded vessel. Crucially, how many attempts should be made at primary MT before rescue stenting is considered. This problem is of more relevance in Asian countries where a higher prevalence of intracranial stenoses is seen in the patient population. Studies have shown that rescue stenting leads to better functional outcome at 3 months, but there is a high failure rate associated with this procedure. Prof. Chapot left us with this thought; it is worth the risk for the chance of a good outcome!
Acute Intracranial Stenting Should be Performed as Rescue Treatment in Failed Recanalization – NO
Prof. Phil White from the UK discussed the cons of acute intracranial stenting in the setting of a failed primary MT. Prof. White pointed out that more than two attempts at MT is associated with poor outcome, but that this doesn’t always mean that acute stenting should be considered. It is often difficult to distinguish a residual thrombus from a stenosis and this is reason enough to reconsider. Rescue stenting is associated with high rates of sICH and SAH, 10% greater than MT alone. Blood in and around the brain leads to challenges in decision making around the use of DAPT and anticoagulants in the setting of an ischemic stroke. In addition, vessel damage is common and can further complicate the situation. Prof. White’s take home message: It can be done but shouldn’t always be done!
On behalf of the ESO and WSO, I would like to thank the speakers for very insightful presentations around the pros and cons of some of the controversies surrounding MT.
