Ultra-Early Intravenous Stroke Thrombolysis

A new machine learning algorithm with high interpretability for improving the safety and efficiency of thrombolysis for stroke patients: A hospital-based pilot study

Background

Thrombolysis is the first-line treatment for patients with acute ischemic stroke. Previous studies leveraged machine learning to assist neurologists in selecting patients who could benefit the most from thrombolysis. However, when designing the algorithm, most of the previous algorithms traded interpretability for predictive power, making the algorithms hard to be trusted by neurologists and be used in real clinical practice.

Methods

Our proposed algorithm is an advanced version of classical k-nearest neighbors classification algorithm (KNN). We achieved high interpretability by changing the isotropy in feature space of classical KNN. We leveraged a cohort of 189 patients to prove that our algorithm maintains the interpretability of previous models while in the meantime improving the predictive power when compared with the existing algorithms. The predictive powers of models were assessed by area under the receiver operating characteristic curve (AUC).

Results

In terms of interpretability, only onset time, diabetes, and baseline National Institutes of Health Stroke Scale (NIHSS) were statistically significant and their contributions to the final prediction were forced to be proportional to their feature importance values by the rescaling formula we defined. In terms of predictive power, our advanced KNN (AUC 0.88) outperformed the classical KNN (AUC 0.75, p = 0.0192 ).

Conclusions

Our preliminary results show that the advanced KNN achieved high AUC and identified consistent significant clinical features as previous clinical trials/observational studies did. This model shows the potential to assist in thrombolysis patient selection for improving the successful rate of thrombolysis.

Prehospital identification of large vessel occlusion using the FAST-ED score

OBJECTIVES

The prehospital identification of stroke patients with large vessel occlusion (LVO) enables appropriate hospital selection and reduces the onset-to-treatment time. The aim of this study was to investigate whether the Field Assessment Stroke Triage for Emergency Destination (FAST-ED) scale could be reconstructed from existing prehospital patient reports and to compare its performance with neurologist's clinical judgement using the same prehospital data.

MATERIALS & METHODS

All patients transported by ambulance using stroke code on a six-month period were registered for the study. The prehospital patient reports were retrospectively evaluated using the FAST-ED scale by two investigators. The performance of FAST-ED score (≥4 points) in LVO identification was compared to neurologist's clinical judgement ('LVO or not'). The presence of LVO was verified using computed tomography angiography imaging.

RESULTS

A total of 610 FAST-ED scores were obtained. The FAST-ED had a sensitivity of 57.8%, specificity of 87.2%, positive predictive value (PPV) of 37.3%, negative predictive value (NPV) of 93.4% and area under curve (AUC) of 0.724. Interclass correlation coefficient for both raters over the entire range of FAST-ED was 0.92 (0.88-0.94). The neurologist's clinical judgement raised sensitivity to 79.4%, NPV to 97.1% and PPV to 45.0% with an AUC of 0.837 (p < .05).

CONCLUSIONS

The existing patient report data could be feasibly used to reconstruct FAST-ED scores to identify LVO. The binary FAST-ED score had a moderate sensitivity and good specificity for prehospital LVO identification. However, the FAST-ED was surpassed by neurologist's clinical judgement which further increased the sensitivity of identification.

EndoVAscular treatment and ThRombolysis for Ischemic Stroke Patients (EVA-TRISP) registry: basis and methodology of a pan-European prospective ischaemic stroke revascularisation treatment registry

PURPOSE

The Thrombolysis in Ischemic Stroke Patients (TRISP) collaboration was a concerted effort initiated in 2010 with the purpose to address relevant research questions about the effectiveness and safety of intravenous thrombolysis (IVT). The collaboration also aims to prospectively collect data on patients undergoing endovascular treatment (EVT) and hence the name of the collaboration was changed from TRISP to EVA-TRISP. The methodology of the former TRISP registry for patients treated with IVT has already been published. This paper focuses on describing the EVT part of the registry.

PARTICIPANTS

All centres committed to collecting predefined variables on consecutive patients prospectively. We aim for accuracy and completeness of the data and to adapt local databases to investigate novel research questions. Herein, we introduce the methodology of a recently constructed academic investigator-initiated open collaboration EVT registry built as an extension of an existing IVT registry in patients with acute ischaemic stroke (AIS).

FINDINGS TO DATE

Currently, the EVA-TRISP network includes 20 stroke centres with considerable expertise in EVT and maintenance of high-quality hospital-based registries. Following several successful randomised controlled trials (RCTs), many important clinical questions remain unanswered in the (EVT) field and some of them will unlikely be investigated in future RCTs. Prospective registries with high-quality data on EVT-treated patients may help answering some of these unanswered issues, especially on safety and efficacy of EVT in specific patient subgroups.

FUTURE PLANS

This collaborative effort aims at addressing clinically important questions on safety and efficacy of EVT in conditions not covered by RCTs. The TRISP registry generated substantial novel data supporting stroke physicians in their daily decision making considering IVT candidate patients. While providing observational data on EVT in daily clinical practice, our future findings may likewise be hypothesis generating for future research as well as for quality improvement (on EVT). The collaboration welcomes participation of further centres willing to fulfill the commitment and the outlined requirements.

Spatial Analysis of Geographic Distribution and Accessibility of Suspected Acute Stroke Patients Transferred to Acute Stroke Centers by Emergency Medical Services in Tehran, Iran: A Cross-Sectional Study

Objectives: We intended to map the geographical distribution of patients with acute stroke who called the Tehran EMS center based on the geographic information of the incident location on a map. The distributions of these centers and patients’ access within a standard period were evaluated. Methods: A cross-sectional study based on the registered data was conducted on suspected acute stroke patients > 18 years of age that were transferred by EMS. The analysis was performed based on pointing the patients’ locations and locating the hospitals in ArcGIS software plus a review of the polygons and focal points. Results: Totally, 1,606 patients suspected to stroke with a mean age of 64.89 ± 17.48 years were evaluated, of whom 947 (58.6%) were male. The mean time of arrival of an ambulance in the patient’s location from the EMS station was 11.94 ± 6.67 minutes, and the longest time was 69.32 minutes. The mean time from the patient’s location to the stroke center was 17.79 ± 11.42 minutes (range 2.4 - 83.70 minutes). Stroke centers in Tehran are not distributed in a balanced manner, and they are concentrated on the central and northern parts of Tehran, limiting access to hospital services. Conclusions: The multiplicity of hospitals in the west and center of Tehran led to an increase in access times in eastern Tehran. It emphasizes the necessity of revision of service locating, especially because the east of Tehran has a denser texture than the west.

Intravenous Thrombolysis Benefits Mild Stroke Patients With Large-Artery Atherosclerosis but No Tandem Steno-Occlusion

At present, there is controversy regarding whether thrombolysis is beneficial for patients suffering from a mild stroke. In this study, we therefore sought to determine whether the therapeutic benefit of thrombolysis is dependent upon stroke subtype for those with mild stroke. We conducted a retrospective analysis of data from consecutive mild stroke patients (National Institutes of Health Stroke Scale ≤5) with and without recombinant tissue plasminogen activator (rt-PA) therapy. The TOAST (Trial of Org 10172 in acute stroke treatment) criteria was used to determine stroke subtypes. Patients suffering from large-artery atherosclerosis (LAA) were subdivided based upon whether or not they exhibited tandem steno-occlusion, as defined by the association of a proximal intracranial occlusion and a cervical internal carotid artery lesion (complete occlusion or severe stenosis ≥ 90%). For this study, favorable outcomes at 90 days of onset (modified Rankin Scale Score [mRS] of 0–1) were the primary measured outcome. Three hundred thirty-nine patients were included in the study. For patients with non-LAA, there were not statistically significant improvements in favorable outcomes for rt-PA treatment (p = 0.889, 0.929, 0.708; respectively). For patients with LAA, compared with non-treated group, rt-PA-treated patients had a significant in the rate of favorable outcomes at 90 days (82.8 vs. 64.9%; OR 2.59; 95%CI, 1.13–5.92; P = 0.024). Among LAA patients exhibiting tandem lesions, favorable outcomes were observed in 66.7% of rt-PA-treated patients, with no significant differences to those observed in untreated patients (OR 1.00; 95%CI, 0.23–4.28; p = 1.000). Among LAA patients without tandem lesions, compared with non-treated group, we found that rt-PA treatment was associated with a significant beneficial impact on favorable outcomes after 90 days (64.4 vs. 88.4%; OR 4.20; 95%CI, 1.43–12.30; p = 0.009). Our findings suggest that intravenous rt-PA is only beneficial in mild stroke patients with LAA-type strokes that do not exhibit tandem steno-occlusion.

Pachymic acid protects against cerebral ischemia/reperfusion injury by the PI3K/Akt signaling pathway

Pachymic acid (PA) from medicinal fungus Poria cocos has a variety of pharmacological potentials. However, there are no reports of the effects of PA on cerebral ischemia/reperfusion (I/R) injury. The purpose of this study was to investigate the mechanisms of PA on cerebral I/R injury in rats. The effects of PA on cerebral infarction size, brain water content, neurological symptoms and cerebral blood flow were evaluated. Nissl staining was used to observe the damage of ischemic brain neurons after I/R in rats. Apoptosis of ischemic brain neurons after I/R was observed by TUNEL staining. The effect of PA on the expression of some components of PI3K/Akt was detected by Western blotting. PA significantly increased cerebral blood flow after I/R in rats, reduced infarct volume and brain water content, and downgrade neurological function scores, significantly reduced neuronal damage after I/R in rats, and significantly decreased neuronal apoptosis. The effect of PA on rat I/R can be eliminated by LY294002. In addition, PA significantly up-regulated the protein expression of p-PTEN (Ser380), p-PDK1 (Ser241), p-Akt (Ser473), pc-Raf (Ser259) and p-BAD (Ser136), and down-regulated Cleaved caspase protein expression. LY294002 can reverse the effect of PA on the expression of PI3K / Akt signaling pathway related protein in rats after I/R. PA had obviously neuroprotective effects on brain I/R injury and neuronal apoptosis, and its mechanism may be related to activation of PI3K / Akt signaling pathway.

Reducing door-to-needle times in stroke thrombolysis to 13 min through protocol revision and simulation training: a quality improvement project in a Norwegian stroke centre

Background

In eligible patients with acute ischaemic stroke, rapid revascularisation is crucial for good outcome. At our treatment centre, we had achieved and sustained a median door-to-needle time of under 30 min. We hypothesised that further improvement could be achieved through implementing a revised treatment protocol and in situ simulation-based team training sessions. This report describes a quality improvement project aiming to reduce door-to-needle times in stroke thrombolysis.

Methods

All members of the acute stroke treatment team were surveyed to tailor the interventions to local conditions. Through a review of responses and available literature, the improvement team suggested changes to streamline the protocol and designed in situ simulation-based team training sessions. Implementation of interventions started in February 2017. We completed 14 simulation sessions from February to June 2017 and an additional 12 sessions from November 2017 to March 2018. Applying Kirkpatrick’s four-level training evaluation model, participant reactions, clinical behaviour and patient outcomes were measured. Statistical process control charts were used to demonstrate changes in treatment times and patient outcomes.

Results

A total of 650 consecutive patients, including a 3-year baseline, treated with intravenous thrombolysis were assessed. Median door to needle times were significantly reduced from 27 to 13 min and remained consistent after 13 months. Risk-adjusted cumulative sum charts indicate a reduced proportion of patients deceased or bedridden after 90 days. There was no significant change in balancing measures (stroke mimics, fatal intracranial haemorrhage and prehospital times).

Conclusions

Implementing a revised treatment protocol in combination with in situ simulation-based team training sessions for stroke thrombolysis was followed by a considerable reduction in door-to-needle times and improved patient outcomes. Additional work is needed to assess sustainability and generalisability of the interventions.

Cohort profile: Thrombolysis in Ischemic Stroke Patients (TRISP): a multicentre research collaboration

PURPOSE

The ThRombolysis in Ischemic Stroke Patients (TRISP) collaboration aims to address clinically relevant questions about safety and outcomes of intravenous thrombolysis (IVT) and endovascular thrombectomy. The findings can provide observational information on treatment of patients derived from everyday clinical practice.

PARTICIPANTS

TRISP is an open, investigator-driven collaborative research initiative of European stroke centres with expertise in treatment with revascularisation therapies and maintenance of hospital-based registries. All participating centres made a commitment to prospectively collect data on consecutive patients with stroke treated with IVT using standardised definitions of variables and outcomes, to assure accuracy and completeness of the data and to adapt their local databases to answer novel research questions.

FINDINGS TO DATE

Currently, TRISP comprises 18 centres and registers >10 000 IVT-treated patients. Prior TRISP projects provided evidence on the safety and functional outcome in relevant subgroups of patients who were excluded, under-represented or not specifically addressed in randomised controlled trials (ie, pre-existing disability, cervical artery dissections, stroke mimics, prior statin use), demonstrated deficits in organisation of acute stroke care (ie, IVT during non-working hours, effects of onset-to-door time on onset-to-needle time), evaluated the association between laboratory findings on outcome after IVT and served to develop risk estimation tools for prediction of haemorrhagic complications and functional outcome after IVT.

FUTURE PLANS

Further TRISP projects to increase knowledge of the effect and safety of revascularisation therapies in acute stroke are ongoing. TRISP welcomes participation and project proposals of further centres fulfilling the outlined requirements. In the future, TRISP will be extended to include patients undergoing endovascular thrombectomy.

Clinical and radiological factors associated with unfavorable outcome after intravenous thrombolysis in patients with mild ischemic stroke

BACKGROUND

A significant proportion of patients with mild ischemic stroke become disabled despite receiving intravenous thrombolytic therapy. The purpose of this study was to assess the clinical and radiological factors associated with unfavorable outcomes in patients with minor ischemic stroke that received intravenous recombinant tissue plasminogen activator (rt-PA) therapy.

METHODS

We identified anterior circulation stroke patients with initial National Institutes of Health Stroke Scale (NIHSS) scores ≤5 who received intravenous thrombolysis within 4.5 h of stroke onset and had pretreatment magnetic resonance (MR)/MR angiography using our prospective stroke database. We analyzed baseline characteristics, infarction patterns on diffusion-weighted imaging (DWI), and steno-occlusive lesions on MR angiography. Unfavorable outcome was defined as a modified Rankin Scale (mRS) score ≥ 2 at 90 days. Logistic regression was used to determine independent predictors of unfavorable outcomes.

RESULTS

Among 121 patients (85 men; mean age, 63.4 ± 11.3 years) included in this study, 46 (38%) had unfavorable outcomes at 90 days and DWI lesion patterns showing infarction in the deep middle cerebral artery (MCA) territory involving the perforating artery area was observed in 47 (38.8%) patients. On multivariable analysis, unfavorable outcomes at 90 days were associated with diabetes [odds ratio (OR), 3.41; 95% confidence interval (CI), 1.06-10.9; P = 0.039), NIHSS score on admission (OR, 2.11; 95% CI, 1.35-3.30; P = 0.001), and infarction in the deep MCA territory on DWI (OR, 4.19; 95% CI, 1.63-10.8; P = 0.003). Lesions in the deep MCA territory was independently associated with early neurological deterioration (P = 0.032). The patients without deep MCA territory infarction had a higher prevalence of cardiac embolism (P = 0.009).

CONCLUSIONS

Higher NIHSS scores, diabetes, and deep MCA territory infarction may be useful for predicting unfavorable outcomes in patients with minor stroke treated with intravenous rt-PA therapy.

The effect of informal caregiver support on utilization of acute health services among home care clients: a prospective observational study

BACKGROUND

Emergency department visits and hospitalizations (EDVH) place a large burden on patients and the health care system. The presence of informal caregivers may be beneficial for reducing EDVH among patients with specific diagnoses. Our objective was to determine whether the presence of an informal caregiver was associated with the occurrence of an EDVH among clients 50 years of age or older.

METHODS

Using a database accessed through the Toronto Central Community Care Access Centre (CCAC), we identified 479 adults over 50 years of age who received home care in Toronto, Canada. Exposure variables were extracted from the interRAI health assessment form completed at the time of admission to the CCAC. EDVH data were linked to provincial records through the CCAC database. Data on emergency room visits were included for up to 6 months after time of admission to home care. Multiple logistic regression analysis was used to identify factors associated with the occurrence of an EDVH.

RESULTS

Approximately half of all clients had an EDVH within 180 days of admission to CCAC home care. No significant association was found between the presence of an informal caregiver and the occurrence of an EDVH. Significant factors associated with an EDVH included: Participants having a poor perception of their health (adjusted OR = 1.68, 95% CI: 1.11-2.56), severe cardiac disorders (adjusted OR = 1.54, 95% CI: 1.04-2.29), and pulmonary diseases (adjusted OR = 1.99, 95% CI: 1.16-3.47).

CONCLUSIONS

The presence of an informal caregiver was not significantly associated with the occurrence of an EDVH. Future research should examine the potential associations between length of hospital stay or quality of life and the presence of an informal caregiver. In general, our work contributes to a growing body of literature that is increasingly concerned with the health of our aging population, and more specifically, health service use by elderly patients, which may have implications for health care providers.

Intravenous Thrombolysis in Chinese Patients with Different Subtype of Mild Stroke: Thrombolysis in Patients with Mild Stroke

Thrombolysis treatment for patients with mild stroke is controversial. The aim of our study was to investigate whether patients with mild stroke or its specific etiologic subtype might benefit from rt-PA therapy. Data were derived from two cohorts of patients with and without rt-PA treatment: (1) the Thrombolysis Implementation and Monitor of Acute Ischemic Stroke in China (TIMS-China) and (2) the China National Stroke Registry (CNSR) database. Patients with mild stroke (defined as National Institutes of Health Stroke Scale ≤5) receiving the rt-PA therapy and without rt-PA therapy were matched in 1:2 for age, sex, stroke severity and etiologic subtype. A total of 134 rt-PA-treated patients were matched to 249 non-rt-PA-treated patients in the study. Among them, 104 (76%) rt-PA-treated patients with mild stroke had good outcome after 3 months compared with 173 (69.5%) non-rt-PA-treated matching cases (odds ratio [OR], 1.48; 95% confidence interval [CI], 0.91–2.43; P = 0.12). Compared with non-rt-PA-treated group, rt-PA-treated patients had good outcome after 3 months in those with stroke subtype of large-artery atherosclerosis (LAA) (80.5% vs 65.1%; OR, 2.19; 95%CI, 1.14–4.21; P = 0.02). For patients with mild stroke, intravenous rt-PA treatment may be effective. Patients with stroke subtype of LAA might benefit more from rt-PA treatment.

The cost-effectiveness of telestroke in the Pacific Northwest region of the USA

Introduction

Using real-world data from the Providence Oregon Telestroke Network, we examined the cost-effectiveness of telestroke from both the spoke and hub perspectives by level of financial responsibility for these costs and by patient stroke severity.

Methods

We constructed a decision analytic model using patient-level clinical and financial data from before and after telestroke implementation. Effectiveness was measured as quality-adjusted life years (QALYs) and was combined with cost per patient outcomes to calculate incremental cost effectiveness ratios (ICERs). Outcomes were generated (a) overall; (b) by stroke severity, via the National Institute of Health Stroke Scale (NIHSS) at time of arrival, defined as low (<5), medium (5–14) and high (>15); and (c) by percentage of implementation costs paid by spokes (0%, 50%, 100%).

Results

Data for 864 patients, 98 pre- and 766 post-implementation, were used to parameterize our model. From the spoke perspective, telestroke had ICERs of US$1322/QALY, US$25,991/QALY and US$50,687/QALY when responsible for 0%, 50%, and 100% of these costs, respectively. Overall, the ICER ranged from US$22,363/QALY to US$71,703/QALY from the hub perspective.

Conclusions

Our results support previous models showing good value, overall. However, costs and ICERs varied by stroke severity, with telestroke being most cost-effective for severe strokes. Telestroke was least cost effective for the spokes if spokes paid for more than half of implementation costs.

Trends in Door-to-Thrombolysis Time in the Safe Implementation of Stroke Thrombolysis Registry

Background and Purpose—

Shorter delays between symptom onset and treatment translate into better outcomes after ischemic stroke thrombolysis. There are considerable intercenter variations in treatment delivery. We analyzed the trends of door-to-needle times (DNTs) in the Safe Implementation of Thrombolysis in Stroke registry between 2003 and 2011.

Methods—

We extracted from the Safe Implementation of Thrombolysis in Stroke registry (n=45 079) year of treatment, center code, DNT, sex, age, National Institutes of Health Stroke Scale, and comorbidity. For each center, the year they joined the registry and the annual volume of patients were determined (<5, 5–24, 25–49, 50–74, 75–99, and ≥100 patients/y).

Results—

DNT was not available for 720 (1.6%) patients. The overall mean (SD) DNT was 73 (37) minutes with a median (interquartile range) of 67 (47–91) minutes. The DNT was 65 (46–90), 68 (50–92), and 72 (51–98) minutes for centers joined early (2003–2005), later (2006–2009), and recently (2009–2011), respectively. Center volume had more robust effect on DNT than year of treatment, and the shortest DNTs were seen in centers with volumes ≥100 patients/y. Earlier enrollment period was also associated with shorter delays.

Conclusions—

Centers that joined the registry earlier and those with high annual volume achieved shorter DNT than centers that joined later and low-volume centers. However, in most of the centers, DNT did not change much during the registry period. A multicenter project aiming to reduce DNT is warranted.

The golden hour Performing an acute ischemic stroke workup

Ischemic stroke is a medical emergency resulting from an embolic or thrombotic occlusion of an intracranial artery. The purpose of this article is to provide acute care nurse practitioners a summary of recent updates on the rapid evaluation and workup for patient selection and treatment with I.V. fibrinolysis.

Collaterals: an important determinant of prolonged ischemic penumbra versus rapid cerebral infarction?

Intravenous tissue plasminogen activator is the mainstay for the treatment of acute ischemic stroke in patients presenting within 4.5 h of symptom onset. Studies have demonstrated that treating patients early leads to improved long-term outcomes. MR imaging currently allows quantification of the ischemic penumbra in order to better identify individuals most likely to benefit from intervention, irrespective of “time last seen normal.” Its increasing use in clinical practice has demonstrated individual differences in rate of infarction. One explanation for this variability is a difference in collateral blood flow. We report two cases that highlight the individual variability of infarction rate, and discuss potential underlying mechanisms that may influence treatment decisions and outcomes.

Thrombolysis in patients with mild stroke: results from the Austrian Stroke Unit Registry

BACKGROUND AND PURPOSE

Apart from missing the approved time window of 4.5 hours, one frequent cause for withholding recombinant tissue plasminogen activator (rt-PA) treatment in patients with ischemic stroke is presentation with mild deficit on admission. We analyzed in a large cohort of patients whether rt-PA treatment is beneficial for this group of patients.

METHODS

From a total of 54 917 patients with ischemic stroke prospectively enrolled in the Austrian Stroke Unit Registry, 890 patients with mild deficit defined as ≤5 points in the National Institutes of Health Stroke Scale treated with and without rt-PA were matched for age, sex, prestroke disability, stroke severity, hypertension, diabetes mellitus, hypercholesterolemia, stroke cause, and clinical stroke syndrome. Functional outcome was assessed using the modified Rankin Scale at 3 months. For data visualization, weighted averages of outcome differences were computed for all age severity combinations and mapped to a color. For quantification of effect sizes, numbers need to treat were calculated.

RESULTS

rt-PA-treated patients with mild deficit had a better outcome after 3 months compared with matched cases without rt-PA treatment (odds ratio [OR], 1.49; 95% confidence interval [CI], 1.17-1.89; P<0.001). In rt-PA-treated patients with mild deficit, the numbers need to treat ranged from 8 to 14. Improvement achieved by rt-PA treatment was observed along the entire age range.

CONCLUSIONS

In our study, intravenous rt-PA treatment was beneficial for patients with mild deficit. Given the observational nature of these results, our data might serve as an incentive for future randomized controlled trials to provide a basis for optimal patient selection.