Monthly Archives: December 2019

Charlotte Zerna, MD, MSc
@CharlotteZerna

Mayer SA, Viarasilpa T, Panyavachiraporn N, Brady M, Scozzari D, Van Harn M, et al. CTA-for-All: Impact of Emergency Computed Tomographic Angiography for All Patients With Stroke Presenting Within 24 Hours of Onset. Stroke. 2019.

Mechanical thrombectomy for acute ischemic stroke in the anterior circulation due to large-vessel occlusion (LVO) has been established as the new standard of care. The ESCAPE trial found no evidence of treatment heterogeneity between subjects in the early and late windows, and treatment effect favoring intervention was seen across all clinical outcomes in the extended time window.¹ The DAWN and DEFUSE 3 trials were then further able to show benefit of mechanical thrombectomy > 6 hours from onset for patients selected by clinical-core mismatch or perfusion-core mismatch via advanced neuroimaging.^{2, 3} But even though benefit clearly exists beyond 6 hours, fast mechanical thrombectomy is critical since an LVO acute ischemic stroke typically leads to destruction of 1.9 million neurons, 14 billion synapses, and 12 km (7.5 miles) of myelinated fibers per minute.⁴ Because LVO can only be diagnosed by time-efficient neurovascular imaging, the authors implemented a CTA-for-All stroke imaging policy in their regional health system for all patients presenting within 24 hours of last known well, regardless of baseline NIHSS scores and eliminating the requirement of obtaining baseline creatinine levels. The new policy applied to stroke codes in both the ED and on hospital floors, whereas before, an emergency CTA was reserved only for patients with acute ischemic stroke confirmed by non-contrast CT who presented within 6 hours of last known well and with an NIHSS score of at least 6 once serum creatinine levels were known.

Name: Parneet Grewal, MD
Hometown: Chicago, IL
Current Position: Vascular Neurology Fellow at Rush University Medical Center, Chicago, IL

Q: What made you interested in a career in stroke?

A: The experience of taking a stroke alert patient who was also 37 weeks pregnant personally to the angiography suite, and watching her beginning to speak and move her limbs after she returned from the procedure and then deliver a baby three weeks later, still makes me smile and feel contented whenever I think back. Starting with this case, my passion for stroke continued to gain ground through each year in residency as I continued to experience firsthand the immense role a vascular neurologist can play in the life of patients affected with this condition.

Q: What has been your career path into this field?

A: I completed all my training, including medical school, in India and then moved to the United States for my residency at the University of Kentucky Medical Center, followed by a fellowship in stroke at Rush University Medical Center.

Stephanie Lyden, MD, BS

Olivot JM, Mlynash M, Inoue M, Marks MP, Wheeler HM, Kemp S, et al. Hypoperfusion Intensity Ratio Predicts Infarct Progression and Functional Outcome in the DEFUSE 2 Cohort. Stroke. 2014;45:1018–1023.

In stroke care, it is important to understand the various factors that influence patients’ risk for infarct progression. In this regard, there has been increasing interest in understanding the collateral circulation. For example, in chronic vessel stenosis, ischemic preconditioning can cause collateral arborization that results in less than expected infarct size if an occlusion at that area of stenosis occurs. Additionally, in patients with large vessel occlusion who do not achieve recanalization, adequate collateral circulation may play a role in reducing infarct size. The use of perfusion imaging has contributed to a better understanding of the collateral circulation.

This study aimed to evaluate the association between the severity of perfusion-weighted imaging abnormalities, using a hypoperfusion intensity ratio (HIR), on infarct progression and functional outcome in the Diffusion and Perfusion Imaging Evaluation for Understanding Stroke Evolution Study 2 (DEFUSE 2). HIR was defined as the proportion of TMax >6 s lesion volume with a Tmax >10 s delay and was dichotomized based on its median value (0.4) into low versus high subgroups and quartiles. Another way this definition was explained is that it is the Tmax 10/6 s ratio and assessed within 4.9 [+/- 2.6] hours after stroke onset. Initial infarct size was determined using diffusion weighted (DWI) imaging in patients who presented within 12 hours of stroke onset in whom endovascular treatment was anticipated. At day 5 from stroke onset of symptoms, final infarct volume was determined using the fluid attenuated inversion recovery (FLAIR) sequence on magnetic resonance imaging (MRI) of the brain. Total infarct growth was determined by the difference between final infarct volume and initial infarct volume. Baseline DWI lesion volume divided by the delay from symptom onset to baseline MRI of the brain calculated the initial infarct growth velocity. Conventional angiography was used to help determine good or poor collateral flow. A modified Rankin Scale ≤ 2 at 90 days was considered a good functional outcome.

Name: Jennifer Harris, MD
Hometown: Berlin, Germany
Current Affiliation: Columbia University Medical Center

Q: What made you interested in a career in stroke?

A: It was a combination of factors. I was a psychology major in my undergraduate studies and became totally fascinated with behavioral neurology in medical school. During my neurology rotation, I was drawn to the acute care aspect of stroke neurology. I found stroke neurology especially clinically rewarding in light of the expanding treatment options available for stroke patients. It is breathtaking to await the next stroke trial that pushes the boundaries of innovation and treatment.

I also enjoy the multidisciplinary aspect of stroke care, which allows me to work closely with emergency medicine, radiology, vascular surgery, neurosurgery, cardiology, rehabilitation medicine, and community services.

Lastly, I find it especially rewarding to take care of stroke patients. To go from normal to being unable to communicate, walk, or see half of the world in an instant is devastating. The passion that I developed for stroke care and the interest in improving outcomes stems from caring for stroke patients.