International Stroke Conference
February 19–21, 2020

Robert Regenhardt, MD, PhD
@rwregen

The session “Expanding Indications for Thrombectomy” at the International Stroke Conference 2020 included several debates about which patients should be treated with thrombectomy (EVT). Moderated by Thabele Leslie-Mazwi and Marc Ribo, topics included whether to treat patients with mild symptoms, tandem occlusions, and large cores.

Pooja Khatri argued to treat patients with mild symptoms. She first defined mild as NIHSS 0-5, as these patients were largely not included in the landmark RCTs. 20-40% of patients with mild symptoms will decline. Dr. Khatri made the point that NIHSS doesn’t modify the treatment effect of EVT; it may be reasonable to expect benefit even with lower NIHSS. While non-randomized data are mixed, a recent meta-analysis showed a non-significant benefit with treatment.

Sandra Narayanan argued instead that patients with mild symptoms should be monitored. She emphasized the importance of this question: 15% of LVO present with mild symptoms. However, we cannot ignore the potential risks to these patients given they present with only mild symptoms. In the Swiss stroke registry, mortality was observed in 9.3% of EVT patients compared to 2.8% without (p=0.06). The ETIS registry showed any ICH occurred in 16.5% of EVT patients compared to 6% without (p=0.008). Another retrospective cohort from 8 centers in US/Barcelona showed symptomatic ICH in 5.8% of EVT patients compared to 0% in those without (p=0.02). Dr. Narayanan argued that we should consider other variables to assess risk before making this decision: collateral score, orthostatic challenge, perfusion imaging, and NIHSS eloquence. It may be best to randomize these patients in ongoing RCTs: TEMPO-2, ENDOLOW, and IN EXTREMIS.

Albert Yoo was asked to make a case against treating tandem occlusions. He argued that there is little randomized data to prove efficacy. Tandem occlusions only accounted for 10% of patients treated in the HERMES meta-analysis. The American Heart Association guidelines suggest it may be reasonable to treat with class 2b evidence, reflecting clinical equipoise. Further, the benefit of EVT decreases with time, and tandem lesions take more time to treat. There is a 10-15% reduction in 90-day functional independence when procedure time increases from 35 min to 80 min. Thrombus fragmentation that occurs when treating tandem occlusions may also be a consideration. Dr. Yoo described these occlusions are often red blood cell clots, which have been shown more likely to embolize. Red blood cell content can also impact the degree of clot contraction. Selection may be especially important for these cases.

Ameer Hassan argued for treating tandem occlusions. While outcomes are not as good as those with isolated intracranial occlusions, the evidence we have suggests outcomes are better for those treated compared to not. Dr. Hassan discussed that time and technique are  important variables we should target for improvement. Improved techniques, such as ReWiSed CARe, show successful reperfusion in 96%. Another important consideration is whether patients should receive acute ICA stents. EASI-TOC is ongoing, but for now the consensus was that it may be best to avoid acute stenting if possible. If stenting is necessary acutely, antiplatelet strategy requires careful consideration. For patients treated with tPA, Dr. Yoo suggested ASA may be sufficient for the first 24h followed by DAPT thereafter. Dr. Hassan, on the other hand, recommended both ASA and GP IIB/IIIa immediately, imaging at 12h, then switching to ASA/Plavix. 

Johanna Fifi made a case to treat patients with large cores. While there is limited RCT data, available evidence suggests there is a benefit. A case control study from Grady suggested that there was a benefit in those with core >50 cc. In the RCTs, there was a benefit even for those with ASPECTS 3-5. Conceding core size affects outcome, she discussed that the faster we treat larger cores, the better given outcomes are highly time dependent for these patients. Dr. Fifi also cautioned that CTP measured core may not be accurate in the very early time window. She concluded that the outer boundary of core volume has yet to be determined.

Bruce Campbell argued against treating all patients with large cores. He cautioned that the major concerns are hemorrhage and malignant edema. HERMES showed that 20% of patients with very large cores have symptomatic ICH. He conceded that some large core patients will likely benefit, but careful selection is needed. We also must be careful not to mislabel patients as large core who are not (CTP vs non-contrast CT). Furthermore, he discussed ongoing trials studying adjuvant therapies, such as glyburide, for patients with large cores. Ongoing RCTs will help us with this decision; TESLA, SELECT 2, RESCUE-Japan, and IN EXTREMIS are ongoing.