Revisiting Transcranial Light Stimulation as a Stroke Therapeutic-Hurdles and Opportunities.

Near-infrared laser therapy, a special form of transcranial light therapy, has been tested as an acute stroke therapy in three large clinical trials. While the NEST trials failed to show the efficacy of light therapy in human stroke patients, there are many lingering questions and lessons that can be learned. In this review, we summarize the putative mechanism of light stimulation in the setting of stroke, highlight barriers, and challenges during the translational process, and evaluate light stimulation parameters, dosages and safety issues, choice of outcomes, effect size, and patient selection criteria. In the end, we propose potential future opportunities with transcranial light stimulation as a cerebroprotective or restorative tool for future stroke treatment.

Symptomatic Carotid Occlusion Is Frequently Associated With Microembolization.

BACKGROUND AND PURPOSE: Symptomatic carotid artery disease is associated with significant morbidity and mortality. The pathophysiologic mechanisms of cerebral ischemia among patients with carotid occlusion remain underexplored. METHODS: We conducted a prospective observational cohort study of patients hospitalized within 7 days of ischemic stroke or transient ischemic attack because of ≥50% carotid artery stenosis or occlusion. Transcranial Doppler emboli detection was performed in the middle cerebral artery ipsilateral to the symptomatic carotid. We describe the prevalence of microembolic signals (MES), characterize infarct topography, and report clinical outcomes at 90 days. RESULTS: Forty-seven patients, 19 with carotid occlusion and 28 with carotid stenosis, had complete transcranial Doppler recordings and were included in the final analysis. MES were present in 38%. There was no difference in MES between those with carotid occlusion (7/19, 37%) compared with stenosis (11/28, 39%; P=0.87). In patients with radiographic evidence of infarction (n=39), 38% had a watershed pattern of infarction, 41% had a nonwatershed pattern, and 21% had a combination. MES were present in 40% of patients with a watershed pattern of infarction. Recurrent cerebral ischemia occurred in 9 patients (19%; 6 with transient ischemic attack, 3 with ischemic stroke). There was no difference in the rate of recurrence in those with compared to those without MES. CONCLUSIONS: Cerebral embolization plays an important role in the pathophysiology of ischemia in both carotid occlusion and stenosis, even among patients with watershed infarcts. The role of aggressive antithrombotic and antiplatelet therapy for symptomatic carotid occlusions may warrant further investigation given our findings.

Middle Cerebral Artery Residual Contrast Stagnation on Noncontrast CT Scan Following Endovascular Treatment in Acute Ischemic Stroke Patients.

BACKGROUND AND PURPOSE: We evaluated the relationship between middle cerebral artery (MCA) residual contrast stagnation on immediate postprocedural noncontrast CT scan and intraparenchymal hemorrhage (IPH) after endovascular treatment in acute ischemic stroke patients. METHODS: The clinical and imaging data from patients with acute unilateral MCA M1 occlusion who underwent endovascular treatment over a 3.5-year period were reviewed. Bilateral M1 segments were selected on the first postangiography CT scan, and average attenuation was determined in Hounsfield units (HU); the difference between average HU values was calculated. Postprocedural CT scans were also evaluated for presence of IPH, defined as hyperdensity persisting on follow-up CT scans obtained >24-hours postprocedure. RESULTS: Of 80 patients included in our series; 10/80 developed IPH on immediate postprocedural CT scan. Patients with IPH had a higher (ipsilateral-contralateral) M1 residual attenuation difference (P < .001). An average ipsilateral M1 attenuation which was ≥5 HU greater than contralateral artery had a 3.8 times increase in relative risk of IPH (95% confidence interval: 2-7.1). CONCLUSION: On immediate postprocedural noncontrast CT scan of stroke patients with acute MCA M1 occlusion after endovascular treatment, higher residual contrast stagnation in the affected MCA, compared to contralateral artery, is associated with an increased risk of IPH.

Differentiating intraparenchymal hemorrhage from contrast extravasation on post-procedural noncontrast CT scan in acute ischemic stroke patients undergoing endovascular treatment.

INTRODUCTION: This study aimed to identify the imaging characteristics that can help differentiate intraparenchymal hemorrhage from benign contrast extravasation on post-procedural noncontrast CT scan in acute ischemic stroke patients after endovascular treatment. METHODS: We reviewed the clinical and imaging records of all acute ischemic stroke patients who underwent endovascular treatment in two hospitals over a 3.5-year period. The immediate post-procedural CT scan was evaluated for the presence of hyperdense lesion(s). The average attenuation of the lesion(s) was measured. Intraparenchymal hemorrhage was defined as a persistent hyperdensity visualized on follow-up CT scan, 24 h or greater after the procedure. RESULTS: Of the 135 patients studied, 74 (55%) patients had hyperdense lesion(s) on immediate post-procedural CT scan. Follow-up scans confirmed the diagnosis of intraparenchymal hemorrhage in 20 of these 74 patients. A receiver operating characteristic analysis showed that the average attenuation of the most hyperdense lesion can differentiate intraparenchymal hemorrhage from contrast extravasation with an area under the curve of 0.78 (p = 0.001). An average attenuation of <50 Hounsfield units (HU) in the most visually hyperattenuating hyperdense lesion had 100 % specificity and 56% sensitivity for identification of contrast extravasations. Petechial hyperdensity was seen in 46/54 (85%) patients with contrast extravasation versus 9/20 (45%) patients with intraparenchymal hemorrhage on the immediate post-procedural CT scan (p < 0.001). CONCLUSION: An average attenuation <50 HU of the most hyperattenuating hyperdense parenchymal lesion on immediate post-procedural CT scan was very specific for differentiating contrast extravasation from intraparenchymal hemorrhage in acute ischemic stroke patients after endovascular treatment.

Diagnosis of stroke by emergency medical dispatchers and its impact on the prehospital care of patients.

BACKGROUND: Emergency medical dispatchers represent the first line of communication with a patient, and their decision plays an important role in the prehospital care of stroke. We evaluated the rate and accuracy of stroke diagnosis by dispatchers and its influence in the prehospital care of potential stroke patients. METHODS: We analyzed the 2009 National Emergency Medical Services Information System. Study population was based on the diagnosis of stroke made by emergency medical technicians (EMT). This was then divided in those coded as stroke/cerebrovascular accident versus others reported by dispatchers and compared with each other. RESULTS: In all, 67,844 cases were identified as stroke by EMT, but transportation time was available for 52,282 cases that represented the final cohort. Cases identified as stroke by dispatchers were 27,566 (52.7%). When this group compared with stroke cases not identified by dispatchers, we found that the mean age was significantly higher (71.2 versus 68.6 years, P<.0001); advanced life support was dispatched more frequently (84% versus 72.8%, P<.0001), dispatchers offered help and instructions to the caller more frequently, and they arrived at a facility at a shorter time (41.8 versus 49.8 minutes, P<0001). Sensitivity and specificity for the diagnosis of stroke by dispatchers were 34.61 and 99.46, respectively. CONCLUSIONS: Recognition of symptoms and diagnosis of a potential stroke by dispatchers positively affect the care of patients by decreasing the arrival time to a hospital and providing the highest level of prehospital care possible. Education is needed to increase dispatcher's detection of stroke cases.