International Stroke Conference
January 24–26

Alexis N. Simpkins, MD, PhD

Session: Acute Neuroimaging Oral Abstracts II.
Date: Thursday, January 25, 2018

Speaker: Steven Warach, MD, PhD, University of Texas Dell Medical School, University of Texas

Now that the time window for endovascular interventions in acute stroke patients has been extended up to 24 hours, it is important to evaluate the proportion of patients that would potentially be eligible during this window in the general population and determine factors that may predict whether a patient will have an acceptable imaging profile. Dr. Steven Warach presented data analyzed from the LESION database that provided some interesting findings on both fronts. After the presentation, I was able to ask Dr. Warach some follow-up questions about his findings.

Question 1: By using your study registry, you were able to provide a population-based assessment of potential candidates that would be eligible for embolectomy in standard and extended time windows. How closely do you think these findings represent patients enrolled in the DEFUSE3 and DAWN studies?

Our sample was from the NINDS Intramural Stroke Database, which records all strokes referred from the ER, thus is a very representative sample. The practice at these hospitals is to obtain MRI with MRA and perfusion on the first encounter in the ER, unless there were a patient contraindication. From this sample collected over a 10-year period, we estimated that 1.4% of all strokes would meet eligibility criteria for extended time window (6-24hr) thrombectomy. This may be a somewhat overestimate, since we did not apply the more restrictive ‘small core’ definition that the clinical trials applied.

Question 2: You found an association between the presence of penumbral volume, NIHSS, time, and presence of a large vessel occlusion. How do you believe these findings may influence new research questions investigating the treatment of acute ischemic stroke patients in the extended time windows?

The most interesting aspect of this finding is that the probability of having a penumbra seems to be independent of clinical severity (measured by the NIHSS) in patients with the target large vessel occlusion (ICA or MCA-M1). However, in patients without a large vessel occlusion, the probability of having a penumbra is directly related to the NIHSS. The latter has implications for designing trials for the next frontier in recanalization — iv thrombolysis in patients > 4.5 h who do not have a large vessel occlusion.