Conference

International Stroke Conference
February 6–8, 2019

Deepak Gulati, MD

During the joint symposium on the last day of the ISC 2019 on Telestroke, multiple experts with different backgrounds addressed the challenges associated with Telestroke. Telestroke turns 20 in 2019, which reflects 2 decades of progress. It was more of proof of concepts in early 2000 while showing benefit of Telestroke in rural areas. Telestroke plays a predominant role in the ‘Drip and Ship’ model in the United States, whereas the focus has been on Telestroke-supported stroke units in Europe. In the U.S., the Congress also authorized the payment for Medicare FFS Telestroke regardless of patient location in the “Furthering Access to Stroke Telemedicine” FAST Act. The future of Telestroke research will be on value (~quality/cost) vs churn, true econometric analyses, adoption within health system, scalability, disparities in access, continuum of care and Telestroke on call expertise vs AI. Based on data provided, there appears to be a connection between door-to-needle time with the number of consults from spoke hospitals. 50% of the Telestroke consults are usually acute stroke, and the rate of IVtpa administration increases with the number of consults performed. It’s expected to have the involvement of artificial intelligence in the future to deal with increasing demand of Telestroke.

International Stroke Conference
February 6–8, 2019

Kat Dakay, DO

Much discussion has taken place about the role of advanced imaging in patient selection for mechanical thrombectomy. In this symposium, Dr. Marc Fisher, Editor-in-Chief of Stroke, moderated a lecture series focused on what imaging to perform in order to select patients for thrombectomy. The lectures were given by Dr. Fisher, Dr. Bruce Campbell (Melbourne Brain Institute, University of Melbourne), Dr. Michael Hill (University of Calgary), Dr. Maarten Lansberg (Stanford), and Dr. Pooja Khatri (University of Cincinnati).

Some themes that came up in the four lectures:

Advanced neuroimaging such as MR perfusion or CT perfusion can help make thrombectomy decisions, and may be especially important in patients presenting in the extended time window as per DAWN and DEFUSE.

• Dr. Lansberg discussed how CT perfusion can extend the time window, and identify patients who may be a high risk for hemorrhage.
• He also cited a meta-analysis titled “Neurons Over Nephrons” published in 2017 that dispelled the notion that CTA/CTP was associated with acute renal injury to help alleviate concerns regarding iodinated contrast exposure.

International Stroke Conference
February 6–8, 2019

Richard Jackson, MD

I’m writing to you from ISC reporting on an extremely well-planned lecture series on symptomatic carotid artery identification by imaging. I’ve always thought this topic extremely vague as the imaging technology progressed, the medical treatment progressed, but the evaluation and treatment remained surgical with guidelines from the 1990s and most of the research spread across multiple sub-specialties. This same sentiment was echoed today in each mini-series lecture. There’s no easy way to summarize each mini lecture except to keep it in its original format and hit the relevant highlights, which are numerous to say the least.

First Lecture: “Ultrasound Imaging of Carotid Wall and Plaque” by J David Spence
His focus is clearly the identification of vulnerable plaques by ultrasound, and he was a proponent of upcoming volumetric plaque morphology assessment. He quotes the prevalence of asymptomatic carotid stenosis in the >60 year old population at 10% and identifies vulnerable plaques using TCD with emboli detection and plaque characteristics as echo-lucency, hemorrhage, and plaque ulcerations. Of interest was a paper he showed in which TMAO and lecithins produced by intestinal flora worsened carotid stenosis. As GFR decreased, including with age, the metabolites increased, possibly explaining the age relationship to carotid stenosis. Also of interest were the timelines in which carotid stenosis responded to medication. He presented his own carotid plaque and showed a transition from hypoechoic to hyperechoic in 3 months with atorvastatin, and then presented a paper in which ezetimibe doubled the effectiveness of statin therapy.

International Stroke Conference
February 6–8, 2019

Burton J. Tabaac, MD
@burtontabaac

First Presenter: Xin Cheng, MD, PhD
This insightful discussion focused on the identification of intracranial atherosclerotic disease (ICAD) and its relationship to large vessel occlusion (LVO). The speaker pointedly detailed the differences in truncal type vs. branching type anatomies. This difference in dynamic may be correlated with baseline NIHSS and size of penumbra, with larger penumbra suggesting better collateral circulation. This portion of the talk was aided by neuroimaging to demonstrate the presence of a “susceptibility vessel sign” (SVS) on GRE/SWI MRI sequencing. If present, SVS suggests an embolic etiology, whereas the absence of SVS suggests ICAD.

The current treatment of ICAD-LVO lacks consensus amongst the scientific community. Notably, patients with ICAD were observed to experience much longer procedure times compared to patients with LVO of embolic origin. The presenter posed the question, “Is endovascular treatment, or even thrombosis, necessary in this subset of patients?” ICAD-LVO is highly common in Asian populations, and there are no definitive clinical and/or imaging profiles for ICAD-LVO patients. It remains to be clear how treatment and patient selection criteria will change, the take-away being that intervention is safe, but it is unclear if it is beneficial.

World Stroke Congress
October 17-20, 2018

Ravinder-Jeet Singh, MBBS, DM

The session on advances in stroke imaging was very interesting and informative. Three speakers — Dr. Ken Butcher from Edmonton and Drs. Gregory Albers and Chitra Venkatasubramanian from Stanford — discussed some of the recent changes in the field of stroke imaging and how it is influencing the practice of stroke care.

Dr. Butcher spoke about multimodal CT based imaging paradigms in acute ischemic stroke, especially use of CTA and CTP in patient selection. It is of note that two of the “early window” EVT trials (SWIFT PRIME and EXTEND IA) and both the late window trials (DAWN and DEFUSE 3) used perfusion imaging for patient selection. He discussed various software platforms available for processing and interpreting CTP data. Options include inbuilt software provided by CT vendors and other commercially available software including RAPID (iSchemaView Inc.), MIstar (Apollo Medical Imaging Technology), and OleaSphere (Olea Medical). The key message was that clinicians should be careful in interpreting CTP images and also the outputs (core, penumbra volumes, and mismatch ratios) provided by these softwares. It is essential to look at arterial input function and venous output function curves to assess the quality of CTP data. These curves should display rapid upslopes and downslopes. Presence of any truncation of these curves should also be noted, which could lead to misestimation of core and penumbra size. In addition, the presence of motion artifacts can severely degrade image quality and, therefore, its interpretation. He also pointed out another important area in which CTP could be helpful — the stroke mimics — where a normal CTP would be reassuring in the appropriate clinical context.