Feasibility and logistics of MRI before thrombolytic treatment

Results of a 1-year quality-improvement process to reduce door-to-needle time in acute ischemic stroke with MRI screening

OBJECTIVE

To determine the effects of a 1-year quality-improvement (QI) process to reduce door-to-needle (DTN) time in a secondary general hospital in which multimodal MRI screening is used before tissue plasminogen activator (tPA) administration in patients with acute ischemic stroke (AIS).

METHODS

The QI process was initiated in January 2015. Patients who received intravenous (iv) tPA<4.5h after AIS onset between 26 February 2015 to 25 February 2016 (during implementation of the QI process; the "2015 cohort") were identified (n=130), and their demographic and clinical characteristics and timing metrics compared with those of patients treated by iv tPA in 2014 (the "2014 cohort", n=135).

RESULTS

Of the 130 patients in the 2015 cohort, 120 (92.3%) of them were screened by MRI. The median DTN time was significantly reduced by 30% (from 84min in 2014 to 59min; P<0.003), while the proportion of treated patients with a DTN time≤60min increased from 21% to 52% (P<0.0001). Demographic and baseline characteristics did not significantly differ between cohorts, and the improvement in DTN time was associated with better outcomes after discharge (patients with a 0-2 score on the modified rankin scale: 59% in the 2015 cohort vs 42.4% in the 2014 cohort; P<0.01). During the 1-year QI process, the median DTN time decreased by 15% (from 65min in the first trimester to 55min in the last trimester; P≤0.04) with a non-significant 1.5-fold increase in the proportion of treated patients with a DTN time≤60min (from 41% to 62%; P=0.09).

CONCLUSION

It is feasible to deliver tPA to patients with AIS within 60min in a general hospital, using MRI as the routine screening modality, making this QI process to reduce DTN time widely applicable to other secondary general hospitals.

Cost-effectiveness and resource use of implementing MRI-guided NACT in ER-positive/HER2-negative breast cancers in The Netherlands

Background

Response-guided neoadjuvant chemotherapy (RG-NACT) with magnetic resonance imaging (MRI) is effective in treating oestrogen receptor positive/human epidermal growth factor receptor-2 negative (ER-positive/HER2-negative) breast cancer. We estimated the expected cost-effectiveness and resources required for its implementation compared to conventional-NACT.

Methods

A Markov model compared costs, quality-adjusted-life-years (QALYs) and costs/QALY of RG-NACT vs. conventional-NACT, from a hospital perspective over a 5-year time horizon. Health services required for and health outcomes of implementation were estimated via resource modelling analysis, considering a current (4 %) and a full (100 %) implementation scenario.

Results

RG-NACT was expected to be more effective and less costly than conventional NACT in both implementation scenarios, with 94 % (current) and 95 % (full) certainty, at a willingness to pay threshold of €20.000/QALY. Fully implementing RG-NACT in the Dutch target population of 6306 patients requires additional 5335 MRI examinations and an (absolute) increase in the number of MRI technologists, by 3.6 fte (full-time equivalent), and of breast radiologists, by 0.4 fte. On the other hand, it prevents 9 additional relapses, 143 cancer deaths, 23 congestive heart failure events and 2 myelodysplastic syndrome/acute myeloid leukaemia events.

Conclusion

Considering cost-effectiveness, RG-NACT is expected to dominate conventional-NACT. While personnel capacity is likely to be sufficient for a full implementation scenario, MRI utilization needs to be intensified.

Patient and Process Factors Associated With Type of First Neuroimaging and Delayed Diagnosis in Childhood Arterial Ischemic Stroke

OBJECTIVES

In-hospital factors contribute more to delayed diagnosis of childhood arterial ischemic stroke (AIS) than prehospital factors. We aimed to explore process and patient factors associated with type of and timing to neuroimaging in childhood AIS in the emergency department (ED).

METHODS

This was a retrospective hospital registry-based study of children with AIS, presenting to an Australian tertiary pediatric ED between January 2003 and December 2012. Neuroimaging data and timelines of care were also collected from referring hospitals for transferred patients.

RESULTS

Seventy-one AIS episodes and 19 transient ischemic attacks were recorded. The majority (56%) were initially seen at a referring hospital. Patients underwent computed tomography (CT) as first scan more frequently than magnetic resonance imaging (MRI) as first scan (61% vs. 32%) at both the referring and the tertiary hospitals. Time to first scan as CT was significantly shorter compared with MRI (median = 1.5 hours vs. 10.9 hours, p < 0.001). MRI was performed more often at the tertiary hospital (92.5% vs. 26%, p = 0.001). Median time to performance of diagnostic MRI was 15.1 hours (interquartile range = 7.1-23.5), with no significant difference between patients first presenting to a referring hospital and those directly accessing the tertiary center. Patient characteristics including age, past medical history, conscious state, focal symptoms, and signs on arrival were not associated with the type of first neuroimaging or time to diagnostic MRI. Patients presenting during weekends were less likely to receive an MRI as first scan (odds ratio [OR] = 0.3, 95% confidence interval [CI] = 0.1-0.8), while time to MRI was significantly longer for children presenting after hours (5 pm-8 am; median = 17.6 hours vs. 8.4 hours, p = 0.026). MRI overall and as first scan was associated with a higher use of sedation than CT (OR = 6.5, 95% CI = 1.3-32.9; and OR = 3.9, 95% CI = 1.3-11.8), particularly for children younger than 5 years of age (OR = 12.5, 95% CI = 3-52.4).

CONCLUSIONS

Strategies to improve rapid diagnosis of pediatric stroke should include shared regional hospital networks protocols to optimize local imaging strategies and where possible rapid transfer to the tertiary center. Future priorities should include development of pediatric ED physician decision support tools to differentiate stroke from mimics and the development and implementation of rapid ED imaging stroke protocols to improve access to confirmatory MRI scanning.

ASPECTS discrepancies between CT and MR imaging: analysis and implications for triage protocols in acute ischemic stroke

BACKGROUND

Optimal imaging triage for intervention for large vessel occlusions remains unclear. MR-based imaging provides ischemic core volumes at the cost of increased imaging time. CT Alberta Stroke Program Early CT Score (ASPECTS) estimates are faster, but may be less sensitive.

OBJECTIVE

To assesses the rate at which MRI changed management in comparison with CT imaging alone.

METHODS

Retrospective analysis of patients with acute ischemic stroke undergoing imaging triage for endovascular therapy was performed between 2008 and 2013. Univariate and multivariate analyses were performed. Multivariate logistic regression was used to evaluate the effect of time on disagreement in MRI and CT ASPECTS scores.

RESULTS

A total of 241 patients underwent both diffusion-weighted imaging (DWI) and CT. Six patients with DWI ASPECTS ≥6 and CT ASPECTS <6 were omitted, leaving 235 patients. For 47 patients, disagreement between the two modalities resulted in different treatment recommendations. The estimated probability of disagreement was 20.0% (95% CI 15.4% to 25.6%). In a multivariate logistic regression, CT ASPECTS >7 (p=0.004) and admission National Institutes of Health Stroke Scale (NIHSS) score <16 (p=0.008) were simultaneously significant predictors of agreement in ASPECTS. The time between modalities was a marginally significant predictor (p=0.080).

CONCLUSIONS

The study suggests that patients with NIHSS scores at admission of <16 and patients with CT ASPECTS >7 have a higher likelihood of agreement between CT and DWI based on an ASPECTS cut-off value of 6. Additional MRI for triage in patients with NIHSS at admission of >16, and ASPECTS of 6 or 7 may be more likely to change management. Unsurprisingly, patients with low CT ASPECTS had good correlation with MRI ASPECTS.

Brain attacks and stroke in children

Emergency physicians are often the first point of contact in children presenting with acute neurological disorders. Differentiating serious disorders, such as stroke, from benign disorders, such as migraine, can be challenging. Clinical assessment influences decision-making, in particular the need for emergent neuroimaging to confirm diagnosis. This review describes the spectrum of disorders causing 'brain attack' symptoms, or acute onset focal neurological dysfunction, with particular emphasis on childhood stroke, because early recognition is essential to improve access to thrombolytic treatments, which have improved outcomes in adults. Clues to diagnosis of specific conditions are discussed. Symptoms and signs, which discriminate stroke from mimics, are described, highlighting differences to adults. Haemorrhagic and ischaemic stroke have different presenting features, which influence choice of the most appropriate imaging modality to maximise diagnostic accuracy. Improvements in the care of children with brain attacks require coordinated approaches and system improvements similar to those developed in adults.

Screening with MRI for Accurate and Rapid Stroke Treatment: SMART

OBJECTIVE

The objective of this study was to demonstrate the feasibility of timely multimodal MRI screening before thrombolysis in acute stroke patients.

METHODS

Quality improvement processes were initiated in 2013 to reduce door-to-needle (DTN) time at the 2 hospitals where the NIH stroke team provides clinical care. Acute ischemic stroke (AIS) patients who received IV tissue plasminogen activator (tPA) ≤4.5 hours from last known normal were identified. Demographic and clinical characteristics and timing metrics were analyzed comparing the time periods before, during, and after the quality improvement processes.

RESULTS

There were 157 patients treated with IV tPA for AIS during 2012-2013, of whom 135 (86%) were screened with MRI. DTN time was significantly reduced by 40% during this period from a median of 93 minutes in the first half of 2012 to 55 minutes in the last half of 2013 (p < 0.0001) with a significant 4-fold increase in the proportion of treated patients with DTN time ≤60 minutes from 13.0% to 61.5%, respectively (p < 0.00001). Improvement in DTN time was associated with reduced door-to-MRI time, and there were no differences in demographic or clinical characteristics (p = 0.21-0.76).

CONCLUSIONS

It is feasible and practical to consistently and rapidly deliver IV tPA to AIS patients within national benchmark times using MRI as the routine screening modality. The processes used in the SMART (Screening with MRI for Accurate and Rapid Stroke Treatment) Study to reduce DTN time have the potential to be widely applicable to other hospitals.

Emergency management of ischemic stroke in children

OPINION STATEMENT

Children who present with acute neurological symptoms suggestive of a stroke need immediate clinical assessment and urgent neuroimaging to confirm diagnosis. Magnetic resonance imaging (MRI) is the investigation of first choice due to limited sensitivity of computed tomography (CT) for detection of ischaemia. Acute monitoring should include monitoring of blood pressure and body temperature, and neurological observations. Surveillance in a paediatric high dependency or intensive care unit and neurosurgical consultation are mandatory in children with large infarcts at risk of developing malignant oedema or haemorrhagic transformation. Thrombolysis and/or endovascular treatment, whilst not currently approved for use in children, may be considered when stroke diagnosis is confirmed within 4.5 to 6 h, provided there are no contraindications on standard adult criteria. Standard treatment consists of aspirin, but anticoagulation therapy is frequently prescribed in stroke due to cardiac disease and extracranial dissection. Steroids and immunosuppression have a definite place in children with proven vasculitis, but their role in focal arteriopathies is less clear. Decompressive craniotomy should be considered in children with deteriorating consciousness or signs of raised intracranial pressure.

Organizational changes aiming to reduce iv tPA door-to-needle time

OBJECTIVES

To assess time trends in intravenous thrombolytic (iv tPA) treatment in a general local hospital during a period with organizational changes, especially how movement of treatment start from the emergency room (ER) to the CT laboratory, and changing method of administration of acute antihypertensive medication influenced on door-to-needle time (DNT).

MATERIALS AND METHODS

All stroke patients treated with iv tPA have been prospectively enrolled in the Safe Implementation of Treatments in Stroke (SITS) registry. Data from 2007 to 2011 were reviewed. Safety was evaluated by the incidence of symptomatic intracerebral hemorrhage (SICH). Predictors of DNT were assessed by multivariable regression.

RESULTS

Two hundred and forty-three patients were treated with iv tPA. The annual treatment rate reached 21.9% of patients with ischemic strokes admitted to the hospital. Median DNT decreased from 36 to 28 min (P ≤ 0.001). The incidence of SICH remained low and was throughout the period 2.5%. Treatment start in the CT laboratory vs in the ER was associated with a reduction in median DNT (P = 0.007). Acute antihypertensive treatment and treatment with warfarin were associated with increased DNT (P = 0.024 and P = 0.003, respectively). Age, gender, baseline NIHSS, onset-to-door time, comorbidity, and method of administration of acute antihypertensive treatment did not influence DNT significantly.

CONCLUSIONS

Streamlining of iv tPA logistics can reduce median DNT to <30 min in a general local hospital. Moving treatment start from the ER to the CT laboratory contributed to reduce DNT. Our organizational model was resistant to influence on DNT by patient age, gender, stroke severity, and time to hospital arrival. The incidence of SICH remained low.

MRI before intraarterial therapy in ischemic stroke: feasibility, impact, and safety

Intraarterial therapy (IAT) in acute ischemic stroke is effective for opening occlusions of major extracranial or intracranial vessels. Clinical efficacy data are lacking pointing to a need for proper patient selection. We examined feasibility, clinical impact, and safety profile of magnetic resonance imaging (MRI) for patient selection before IAT. In this single-center study, we collected epidemiologic, imaging, and outcome data on all intraarterial-treated patients presenting with anterior circulation occlusions at our center from 2004 to 2011. Magnetic resonance imaging was the first imaging choice. Computer tomography (CT) was performed in the presence of a contraindication. We treated 138 patients. Mean age was 64 years and median National Institutes of Health Stroke Scale (NIHSS) was 17. Major reperfusion (thrombolysis in cerebral infarction (TICI) 2b+3) was achieved in 52% and good outcome defined as modified Rankin Scale (mRS) score 0 to 2 at 90 days was achieved in 41%. Mortality at 90 days was 10%. There was only one symptomatic hemorrhage. Recanalization, age, and stroke severity were associated with outcome. Preprocedure MRI was obtained in 83%. Good outcome was significantly associated with smaller diffusion-weighted imaging (DWI) lesion size at presentation and not with the size of the perfusion lesion. It is feasible to triage patients for IAT using MRI with acceptable rates of poor outcome and symptomatic hemorrhage.

Imaging-based treatment selection for intravenous and intra-arterial stroke therapies: a comprehensive review

Reperfusion therapy is the only approved treatment for acute ischemic stroke. The current approach to patient selection is primarily based on the time from stroke symptom onset. However, this algorithm sharply restricts the eligible patient population, and neglects large variations in collateral circulation that ultimately determine the therapeutic time window in individual patients. Time alone is unlikely to remain the dominant parameter. Alternative approaches to patient selection involve advanced neuroimaging methods including MRI diffusion-weighted imaging, magnetic resonance and computed tomography perfusion imaging and noninvasive angiography that provide potentially valuable information regarding the state of the brain parenchyma and the neurovasculature. These techniques have now been used extensively, and there is emerging evidence on how specific imaging data may result in improved clinical outcomes. This article will review the major studies that have investigated the role of imaging in patient selection for both intravenous and intra-arterial therapies.

Thrombolysis in acute ischaemic stroke: an update

Stroke is a major cause of mortality and morbidity, and thrombolysis has served as a catalyst for major changes in the management of acute ischaemic stroke. Intravenous alteplase (recombinant tissue plasminogen activator) is the only approved thrombolytic agent at present indicated for acute ischaemic stoke. While the licensed time window extends to 3h from symptom onset, recent data suggest that the trial window can be extended up to 4.5 h with overall benefit. Nonetheless, 'time is brain' and every effort must be made to reduce the time delay to thrombolysis. Intracranial haemorrhage is the major complication associated with thrombolysis, and key factors increasing risk of haemorrhage include increasing age, high blood pressure, diabetes and stroke severity. Currently, there is no direct evidence to support thrombolysis in patients >80 years of age, with a few case series indicating no overt harm. Identification of viable penumbra based on computed tomography/magnetic resonance imaging may allow future extension of the time window. Adjuvant transcranial Doppler ultrasound has the potential to improve reperfusion rates. While intra-arterial thrombolysis has been in vogue for a few decades, there is no clear advantage over intravenous thrombolysis. The evidence base for thrombolysis in specific situations (e.g. dissection, pregnancy) is inadequate, and individualized decisions are needed, with a clear indication to the patient/carer about the lack of direct evidence, and the risk-benefit balance. Patient-friendly information leaflets may facilitate the process of consent for thrombolysis. This article summarizes the recent advances in thrombolysis for acute ischaemic stroke. Key questions faced by clinicians during the decision-making process are answered based on the evidence available.