The Edmonton-based mobile stroke unit (MSU), which transports patients to the University of Alberta Hospital (UAH), enrolled patients in the Intravenous Tenecteplase Compared with Alteplase for Acute Ischemic Stroke (AcT) trial. We examined the feasibility of trial enrollment in MSU, its impact on acute stroke workflow metrics and functional outcomes at 90–120 days.

In this post hoc analysis, patients were divided into three groups based on enrollment site: MSU (n = 43), UAH (n = 273) and non-UAH (n = 1261). All patients were enrolled with a deferred consent process. The primary outcome for this analysis was the feasibility of enrollment defined as the proportion of patients receiving intravenous thrombolysis (IVT) during the study period who were enrolled in the trial. Multiple linear and binary logistic regression was used to evaluate the adjusted effect of the study groups on acute stroke workflow metrics and functional outcomes at 90–120 days.

100% of eligible IVT-treated patients in the MSU during the study period were enrolled in the AcT trial. Covariate-adjusted linear regression showed shorter door-to-needle (17.2 [9.7–24.6] min) and CT-to-needle (10.7 [4.2–17.1] min) times in the MSU compared to UAH and non-UAH sites. There was no difference in the proportion of patients with an excellent functional outcome (mRS 0–1) at 90–120 days or symptomatic intracerebral hemorrhage (ICH) at 24 hours between groups.

Enrollment in the AcT trial from the MSU was feasible. MSU-enrolled patients demonstrated faster door-to-needle and CT-to-needle times, resulting in earlier IVT administration and similar rates of symptomatic ICH.

Clinical trials often struggle to recruit enough participants, with only 10% of eligible patients enrolling. This is concerning for conditions like stroke, where timely decision-making is crucial. Frontline clinicians typically screen patients manually, but this approach can be overwhelming and lead to many eligible patients being overlooked.

To address the problem of efficient and inclusive screening for trials, we developed a matching algorithm using imaging and clinical variables gathered as part of the AcT trial (NCT03889249) to automatically screen patients by matching these variables with the trials’ inclusion and exclusion criteria using rule-based logic. We then used the algorithm to identify patients who could have been enrolled in six trials: EASI-TOC (NCT04261478), CATIS-ICAD (NCT04142125), CONVINCE (NCT02898610), TEMPO-2 (NCT02398656), ESCAPE-MEVO (NCT05151172), and ENDOLOW (NCT04167527). To evaluate our algorithm, we compared our findings to the number of enrollments achieved without using a matching algorithm. The algorithm’s performance was validated by comparing results with ground truth from a manual review of two clinicians. The algorithm’s ability to reduce screening time was assessed by comparing it with the average time used by study clinicians.

The algorithm identified more potentially eligible study candidates than the number of participants enrolled. It also showed over 90% sensitivity and specificity for all trials, and reducing screening time by over 100-fold.

Automated matching algorithms can help clinicians quickly identify eligible patients and reduce resources needed for enrolment. Additionally, the algorithm can be modified for use in other trials and diseases.

We investigated the impact of workflow times on the outcomes of patients treated with endovascular thrombectomy (EVT) in the late time window.

Individual patients’ data who underwent EVT in the late time window (onset to imaging >6 hours) were pooled from seven registries and randomized clinical trials. Multiple time intervals were analyzed. Mixed-effects logistic regression was used to estimate the likelihood of functional independence at 90 days (modified Rankin Scale 0–2). Mixed-effects negative binomial regression was used to evaluate the relationship between patient characteristics and workflow time intervals.

608 patients were included. The median age was 70 years (IQR: 58–71), 307 (50.5%) were female, and 310 (53.2%) had wake-up strokes. Successful reperfusion was achieved in 493 (81.2%) patients, and 262 (44.9%) achieved 90-day mRS 0–2. The estimated odds of functional independence decreased by 13% for every 30 minute delay from emergency department (ED) arrival to imaging time and by 7% from ED arrival to the end of EVT in the entire cohort. Also, the estimated odds of functional independence decreased by 33% for every 30 minute delay in the interval from arterial puncture to end of EVT, 16% in the interval from arrival in ED to end of EVT and 6% in the interval from stroke onset to end of EVT among patients who had a wake-up stroke.

Faster workflow from ED arrival to end of EVT is associated with improved functional independence among stroke patients treated in the late window.

Cervico-cephalic arterial dissections (CeAD) are an important cause of stroke in young patients. This study aimed to determine the frequency and predictors of recanalization in spontaneous CeAD and to study the effect of recanalization on functional outcomes.

We identified patients presenting with acute ischemic stroke secondary to CeAD from the CT angiography (CTA) database of the Calgary Stroke Program. Dissections were diagnosed based on standard clinical and imaging findings. At the discretion of treating stroke Neurologists, the patients were either treated with single antiplatelet or dual antiplatelet or triple therapy. Follow-up imaging with CTA, magnetic resonance imaging, and DSA was completed, and a Modified Rankin scale (mRS) was performed to determine the outcome.

Fifty-six patients with CeAdD were studied. Thirty-four patients (18 VAD; vertebral artery dissection and 16 CAD; carotid artery dissection) were followed up for recanalization. Complete recanalization was observed in 27 subjects; 13 patients with VAD recanalized in comparison to 14 with CAD (p = 0.40). All non-recanalized patients had hypertension. A good clinical outcome (mRS ≤ 2) was observed in 47 patients. Interestingly, the likelihood of a good neurological outcome was not influenced by recanalization status. There was no difference in clinical outcome for different sites in VAD, whereas patients with intracranial CAD had severe strokes (NIHSS > 21).

CeAD has good recanalization rates and neurological outcomes, with recanalization seen even in vessels with initial complete occlusion. The presence of hypertension may influence recanalization. The efficacy of dual antiplatelets and heparin for early recanalization needs to be assessed in future clinical trials.

We have theorized that clots with stasis are longer. We therefore explored the relationship between thrombus imaging characteristics on noncontrast computed tomography (NCCT) and magnetic resonance imaging (MRI) with clot length and pial collaterals on baseline computed tomography angiography (CTA).

Prospective study of acute ischemic stroke patients (2005-2009) from Keimyung University. Patients with known stroke symptom onset time, baseline CTA, MRI, and with M1-Middle Cerebral Artery (MCA)±intracranial internal carotid artery (ICA) occlusions were included. Clot length and pial collaterals were measured on baseline CTA.

A total of 104 patients (mean age 65.1±12.28 years, 56.7% male, median baseline National Institutes of Health Stroke Scale 13) with intracranial ICA + MCA (n=50) or isolated M1-MCA (n=54) occlusions were included. Hyperdense sign on NCCT had a median clot length of 42.3 mm versus 29.5 mm when hyperdense negative (p=0.02). Clots showing blooming artifact on gradient recall echo MRI had a median length of 39.1 mm versus 24.5 mm without blooming (p=0.005). Patients with poor baseline collaterals on CTA had longer clots than those with intermediate/good collaterals (median clot length 49.4 mm vs 34.9 mm vs 20.5 mm respectively, p<0.001). In censored logistic regression modeling, clot length was an independent predictor of hyperdense sign (p=0.05) and of the presence of blooming artifact (p=0.006).

Clot length and baseline collateral status are independent predictors of clot hyperdensity on NCCT and blooming artifact on gradient recall echo. Longer clots are more likely to be hyperdense and to bloom more, probably because portions of these clots are freshly formed locally due to of stasis of blood around the original clot. This stasis could be because of poor collaterals and inefficient angio-architecture within the cerebral arterial tree.