Poststroke Montreal Cognitive Assessment and Recurrent Stroke in Patients With Symptomatic Intracranial Atherosclerosis

BACKGROUND AND PURPOSE

Cognitive impairment occurs in 20%-40% of stroke patients and is a predictor of long-term morbidity and mortality. In this study, we aim to determine the association between poststroke cognitive impairment and stroke recurrence risk, in patients with anterior versus posterior circulation intracranial stenosis.

METHODS

This is a post-hoc analysis of the Stenting and Aggressive Medical Therapy for Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS) trial. The primary predictor was poststroke cognitive function measured by Montreal Cognitive Assessment (MOCA) at 3-6 months and the primary outcome was recurrent ischemic stroke. We used univariate and multivariable cox-regression models to determine the associations between MOCA at 3-6 months and recurrent stroke.

RESULTS

Of the 451 patients enrolled in SAMMPRIS, 393 patients met the inclusion criteria. The mean age of the sample (in years) was 59.5 ± 11.3, 62.6% (246 of 393) were men. Fifty patients (12.7%) had recurrent ischemic stroke during a mean follow up of 2.7 years. The 3-6 month MOCA score was performed on 351 patients. In prespecified multivariable models, there was an association between 3 and 6 month MOCA and recurrent stroke (hazard ratio [HR] per point increase .93 95% confidence interval [CI] .88-.99, P = .040). This effect was present in anterior circulation stenosis (adjusted HR per point increase .92 95% CI .85-0.99, P = .022) but not in posterior circulation artery stenosis (adjusted HR per point increase 1.00 95% .86-1.16, P = .983).

CONCLUSIONS

Overall, we found weak associations and trends between MoCA at 3-6 months and stroke recurrence but more notable and stronger associations in certain subgroups. Since our study is underpowered, larger studies are needed to validate our findings and determine the mechanism(s) behind this association.

Joint time-frequency analysis of dynamic cerebral autoregulation using generalized harmonic wavelets

OBJECTIVE

To develop a joint time-frequency analysis technique based on generalized harmonic wavelets (GHWs) for dynamic cerebral autoregulation (DCA) performance quantification.

APPROACH

We considered two groups of human subjects to develop and validate the method: 55 healthy volunteers and 35 stroke-free subjects with unilateral internal carotid artery stenosis (CAS). We determined the mean and coherence-weighted average of the phase shift (PS) of appropriately defined GHW-based transfer functions, based on data points over the joint time-frequency domain. We compared agreement of standard transfer function analysis (TFA) and GHW analyses in healthy subjects using Bland-Altman plots. We assessed sensitivity of each metric to detect the presumed side-to-side difference in DCA function in CAS subjects (with decreased PS on the occluded side), using McNemar's chi square test to compare each metric to the standard TFA approach. An alternative Morlet wavelet-based approach was also considered.

MAIN RESULTS

The GHW and TFA methods exhibited strong agreement in healthy subjects. Among CAS subjects, GHW metrics outperformed TFA and Morlet wavelet-based approaches in identifying expected side-to-side differences: TFA sensitivity was 40.0% (95%CI 23.9-57.9), Morlet 60.0% (95%CI 42.1-76.1), and GHW  >70% for both metrics (GHW mean PS sensitivity 74.3, 95%CI 56.7-87.5, p   =  0.0027 versus TFA; GHW coherence-weighted PS sensitivity 71.4, 95%CI 53.7-85.4, p   =  0.0009 versus TFA).

SIGNIFICANCE

In comparison to the widely used stationary Fourier transform-based TFA and to Morlet wavelet-based analysis, our data suggest that the GHW-based analysis performs better in identifying DCA asymmetry between the two cerebral hemispheres in patients with high grade unilateral carotid stenosis. Our method may provide enhanced confidence in employing DCA metrics as a sensitive diagnostic tool for detecting impaired DCA function in a variety of pathological settings.

Spatial coefficient of variation of arterial spin labeling MRI as a cerebrovascular correlate of carotid occlusive disease

Clinical interpretation of arterial spin labeling (ASL) perfusion MRI in cerebrovascular disease remains challenging mainly because of the method's sensitivity to concomitant contributions from both intravascular and tissue compartments. While acquisition of multi-delay images can differentiate between the two contributions, the prolonged acquisition is prone to artifacts and not practical for clinical applications. Here, the utility of the spatial coefficient of variation (sCoV) of a single-delay ASL image as a marker of the intravascular contribution was evaluated by testing the hypothesis that sCoV can detect the effects of differences in label arrival times between ipsi- and contra-lateral hemispheres even in the absence of a hemispheric difference in CBF. Hemispheric lateralization values for sCoV and CBF were computed from ASL images acquired on 28 patients (age 73.9 ± 10.2 years, 8 women) with asymptomatic unilateral carotid occlusion. The results showed that sCoV lateralization predicted the occluded side with 96.4% sensitivity, missing only 1 patient. In contrast, the sensitivity of the CBF lateralization was 71.4%, with 8 patients showing no difference in CBF between hemispheres. The findings demonstrate the potential clinical utility of sCoV as a cerebrovascular correlate of large vessel disease. Using sCoV in tandem with CBF, vascular information can be obtained in image processing without the need for additional scan-time.

Abstract TP483: Transcatheter Aortic Valve Replacement (TAVR) Does Not Improve Cerebral Hemodynamics or Neurocognition in Patients With Severe Aortic Stenosis

Objective: To determine if aortic stenosis (AS) is associated with altered cerebral hemodynamics and impaired neurocognition, and whether TAVR improves hemodynamics and cognition.

Background: AS results in higher systolic pressure to overcome resistance from the stenotic valve, leading to heart failure and decline in cardiac output. There has been no baseline assessment of CBF with neurocognition in AS, or the effects of valve replacement.

Methods: In 40 patients with planned TAVR, transcranial Doppler (TCD) assessed bilateral MCA mean flow velocity (MFV); abnormality was < 30cc/sec. The neurocognitive battery assessed memory, language, attention, visual-spatial skills, and executive function, yielding an average Z-score. Impairment was < 1.5 SD’s below the normative mean.

Results: The mean age was 78 years, 59% male, and the mean valve gradient was 46.87%. Mean follow-up was 36 days post-TAVR (range 27 - 55). Before TAVR, the average MFV was 42 cc/sec (SD=10.22), and the mean cognitive score was -0.22 SD’s (range -1.99 to 1.08) below the normative mean. Of the 5 with abnormal MFV’s, none had abnormal cognition (average=0.19 SD’s above the normative mean). After TAVR, the MFV was 43 cc/sec, not different from baseline (p=0.56). The post-TAVR average Z-score was 0.01 SD’s above the normative mean, also not different from baseline (p=0.29). There was no correlation between the change scores in MFV and in neurocognition (r = 0.08, p= 0.69).

Conclusions: Among patients with severe AS, there was no correlation at baseline between abnormal MFV’s on TCD and abnormal neurocognition. It was therefore unsurprising that there was little impact of valve replacement on these measures of cerebral blood flow and brain function. Prior assumptions about diminished CBF and the relationship to cognitive function may not be supported.

Abstract TP141: Can the Human Eye Match a Computer Algorithm in Identifying Hypoperfusion in Asymptomatic Carotid Artery Stenosis?

Background: Perfusion weighted imaging on MRI (MRP) and computerized tomography perfusion (CTP) are increasingly required to manage large vessel disease. Computerized algorithms can quantify perfusion data, but the programs are expensive and not widely used outside acute stroke evaluation. We aimed to determine how well human observers can identify asymmetries in cerebral perfusion images compared with an automated computer algorithm.

Methods: Ten clinicians experienced in treating carotid artery disease (4 vascular neurologists, 3 neuroradiologists, 1 vascular surgeon, 1 neurosurgeon, 1 interventional radiologist) were given 28 post-processed, color-coded, axial-slice MRP scans from patients in the Carotid Revascularization Endovascular versus Stenting Trial - Hemodynamics (CREST-H) study. All patients had >70%, unilateral, asymptomatic carotid artery stenosis and had varying degrees of time-to-peak (TTP) delay on the side of stenosis, ranging from 0 to 2 secs, quantified by a semi-automated system that computes quantitative perfusion maps, using deconvolution of tissue and arterial signals (Olea, Cambridge, MA). A minimum volume of 10cc was required for a given TTP delay. Clinicians were asked to determine asymmetry (y/n) and side of occlusion for each case. Number of correct responses that matched the computer output were tallied.

Results: We averaged correct responses by the 10 clinicians for cases at each increment of TTP delay; (Figure). At TTP delays ≥1.5 seconds, accuracy was ≥80%. At 1.25 sec accuracy fell to 60%, and at ≤ 1 sec, accuracy was ≤50%. For TTP=0 (no asymmetry), accuracy was 71%.

Conclusions: Visual impression of hemodynamic asymmetry among experienced clinicians was reasonably accurate for TTP delays ≥1.5 seconds, but declined with more subtle asymmetries. Depending on the clinical impact of TTP delays (for CREST-H: correlation with cognitive decline), experienced clinicians may perform as well as an automated algorithm.

Changes on Dynamic Cerebral Autoregulation Are Associated with Delayed Cerebral Ischemia in Patients with Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

Early identification of vasospasm prior to symptom onset would allow prevention of delayed cerebral ischemia (DCI) in aneurysmal subarachnoid hemorrhage (aSAH). Dynamic cerebral autoregulation (DCA) is a noninvasive means of assessing cerebral blood flow regulation by determining independence of low-frequency temporal oscillations of systemic blood pressure (BP) and cerebral blood flow velocities (CBFV).

METHODS

Eight SAH patients underwent prospectively a median of 7 DCA assessments consisting of continuous measurements of BCFV and BP. Transfer function analysis was applied to calculate average phase shift (PS) in low (0.07-0.2 Hz) frequency range for each hemisphere as continuous measure of DCA. Lower PS indicated poorer regulatory response. DCI was defined as a 2-point decrease in Glasgow Coma Score and/or infarction on CT.

RESULTS

Three subjects developed symptomatic vasospasm with median time-to-DCI of 9 days. DCI was significantly associated with lower PS over the entire recording period (Wald = 4.28; p = 0.039). Additionally, there was a significant change in PS over different recording periods after adjusting for DCI (Wald = 15.66; p = 0.001); particularly, a significantly lower mean PS day 3-5 after bleed (14.22 vs 27.51; p = 0.05).

CONCLUSIONS

DCA might be useful for early detection of symptomatic vasospasm. A larger cohort study of SAH patients is currently underway.

A Multilevel Analysis of Surgical Category and Individual Patient-Level Risk Factors for Postoperative Stroke

Background and Purpose

Many studies supporting the association between specific surgical procedure categories and postoperative stroke (POS) do not account for differences in patient-level characteristics between and within surgical categories. The risk of POS after high-risk procedure categories remains unknown after adjusting for such differences in patient-level characteristics.

Methods

Using inpatients in the American College of Surgeons National Surgical Quality Initiative Program database, we conducted a retrospective cohort study between January 1, 2000, and December 31, 2010. Our primary outcome was POS within 30 days of surgery. We characterized the relationship between surgical- and individual patient-level factors and POS by using multivariable, multilevel logistic regression that accounted for clustering of patient-level factors with surgical categories.

Results

We identified 729 886 patients, 2703 (0.3%) of whom developed POS. Dependent functional status (odds ratio [OR]: 4.11, 95% confidence interval [95% CI]: 3.60-4.69), history of stroke (OR: 2.35, 95%CI: 2.06-2.69) or transient ischemic attack (OR: 2.49 95%CI: 2.19-2.83), active smoking (OR: 1.20, 95%CI: 1.08-1.32), hypertension (OR: 2.11, 95%CI: 2.19-2.82), chronic obstructive pulmonary disease (OR: 1.39 95%CI: 1.21-1.59), and acute renal failure (OR: 2.35, 95%CI: 1.85-2.99) were significantly associated with POS. After adjusting for clustering, patients who underwent cardiac (OR: 11.25, 95%CI: 8.52-14.87), vascular (OR: 4.75, 95%CI: 3.88-5.82), neurological (OR: 4.60, 95%CI: 3.48-6.08), and general surgery (OR: 1.40, 95%CI: 1.15-1.70) had significantly greater odds of POS compared to patients undergoing other types of surgical procedures.

Conclusions

Vascular, cardiac, and neurological surgery remained strongly associated with POS in an analysis accounting for the association between patient-level factors and surgical categories.

National Institutes of Health StrokeNet Training Core

Background and Purpose- The National Institutes of Health (NIH) StrokeNet provides a nationwide infrastructure to advance stroke research. Capitalizing on this unique opportunity, the NIH StrokeNet Training Core (NSTC) was established with the overarching goal of enhancing the professional development of a diverse spectrum of professionals who are embedded in the stroke clinical trials network of the NIH StrokeNet. Methods- This special report provides a descriptive account of the rationale, organization, and activities of the NSTC since its inception in 2013. Current processes and their evolution over time for facilitating training of NIH StrokeNet trainees have been highlighted. Data collected for monitoring training are summarized. Outcomes data (publications and grants) collected by NSTC was supplemented by publicly available resources. Results- The NSTC comprises of cross-network faculty, trainees, and education coordinators. It helps in the development and monitoring of training programs and organizes educational and career development activities. Trainees are provided directed guidance towards their mandated research projects, including opportunities to present at the International Stroke Conference. The committee has focused on developing sustainable models of peer-to-peer interaction and cross-institutional mentorships. A total of 124 professionals (43.7% female, 10.5% underrepresented minorities) have completed training between 2013 and 2018, of whom 55% were clinical vascular neurologists. Of the total, 85% transitioned to a formal academic position and 95% were involved in stroke research post-training. Altogether, 1659 indexed publications have been authored or co-authored by NIH StrokeNet Trainees, of which 58% were published during or after their training years. Based on data from 109 trainees, 33% had submitted 72 grant proposals as principal or co-principal investigators of which 22.2% proposals have been funded. Conclusions- NSTC has provided a foundation to foster nationwide training in stroke research. Our data demonstrate strong contribution of trainees towards academic scholarship. Continued innovation in educational methodologies is required to adapt to unique training opportunities such as the NIH StrokeNet.

Geographic Analysis of Mobile Stroke Unit Treatment in a Dense Urban Area: The New York City METRONOME Registry

Background Mobile stroke units (MSUs) reduce time to intravenous thrombolysis in acute ischemic stroke. Whether this advantage exists in densely populated urban areas with many proximate hospitals is unclear. Methods and Results We evaluated patients from the METRONOME (Metropolitan New York Mobile Stroke) registry with suspected acute ischemic stroke who were transported by a bi-institutional MSU operating in Manhattan, New York, from October 2016 to September 2017. The comparison group included patients transported to our hospitals via conventional ambulance for acute ischemic stroke during the same hours of MSU operation (Monday to Friday, 9 am to 5 pm). Our exposure was MSU care, and our primary outcome was dispatch-to-thrombolysis time. We estimated mean differences in the primary outcome between both groups, adjusting for clinical, demographic, and geographic factors, including numbers of nearby designated stroke centers and population density. We identified 66 patients treated or transported by MSU and 19 patients transported by conventional ambulance. Patients receiving MSU care had significantly shorter dispatch-to-thrombolysis time than patients receiving conventional care (mean: 61.2 versus 91.6 minutes; P=0.001). Compared with patients receiving conventional care, patients receiving MSU care were significantly more likely to be picked up closer to a higher mean number of designated stroke centers in a 2.0-mile radius (4.8 versus 2.7, P=0.002). In multivariable analysis, MSU care was associated with a mean decrease in dispatch-to-thrombolysis time of 29.7 minutes (95% CI, 6.9-52.5) compared with conventional care. Conclusions In a densely populated urban area with a high number of intermediary stroke centers, MSU care was associated with substantially quicker time to thrombolysis compared with conventional ambulance care.

Cognition and Quality of Life in Symptomatic Carotid Occlusion

PURPOSE

Carotid occlusion may result in stroke, TIA, and cognitive reductions. Whether cognition predicts quality of life (QOL) for patients with carotid occlusion is unknown. Depression is also known to affect QOL. We examined whether cognition and depression predicted QOL in patients with carotid occlusive disease who have not had revascularization.

METHODS

Patients with unilateral carotid occlusion and history of TIA or a remote history of minor stroke were included. Patients underwent exam of memory, language, motor, and executive function skills and completed depression and QOL questionnaires (Center for Epidemiological Studies-Depression [CES-D], Stroke Specific QOL [SSQOL]). Deficits from remote stroke were assessed with the NIH Stroke Scale (NIHSS). Z-scores for cognitive tests were averaged (Cog-Z). The SSQOL scores were averaged across subgroup domains. Analyses of patients with all depression levels were followed by subgroup analyses for patients with minimal depression. Correlation findings were used to select the variables in a regression model to predict SSQOL.

RESULTS

Among 37 patients with all depression levels, QOL was predicted by deficits from remote stroke and depression (F(3, 36) = 21.15, P<.0005; NIHSS Beta = -.392, P = .001; CES-D Beta = -.577, P < .0005). Among 22 patients with minimal depression, QOL was predicted by cognitive and depression scores, (F(2,21) = 7.88, P = .003; Cog-Z Beta = .364, P = .05; CES-D Beta = -.495, P = .01).

CONCLUSIONS

In patients with carotid occlusive disease without major stroke and without revascularization, cognitive and depression scores independently predicted QOL. These data demonstrate the clinical relevance of cognitive and mood decline among patients with carotid occlusion.

Abstract WP104: Clinical Characteristics of Stroke Mimics Treated on an Urban Mobile Stroke Unit

Introduction: It is unknown how the clinical characteristics of stroke mimics treated on Mobile Stroke Units (MSUs) compare to confirmed acute strokes treated on these units.

Methods: We retrospectively analyzed all patients transported by the NewYork-Presbyterian MSU in New York City from October 2016-May 2018. A vascular neurologist assigned a final diagnosis after comprehensive medical record review. Clinical data were abstracted, including comorbidities, presenting symptoms, stroke severity, acute treatments, and short-term outcomes. We compared characteristics of patients with a stroke mimic diagnosis versus those with acute ischemic or hemorrhagic stroke using targeted minimum loss-based estimation to adjust for demographics, comorbidities, NIH Stroke Scale (NIHSS) score, and intravenous tPA administration.

Results: Among 92 suspected stroke patients transported by MSU, 56 (61%) had confirmed acute stroke (77% ischemic, 23% hemorrhagic) and 36 (39%) had a stroke mimic. Mimics consisted of seizure (n=8), metabolic encephalopathy (n=6), somatoform disorders (n=4), and others (n=18). The mean NIHSS score was 8 (SD 7) among mimics versus 11 (SD 8) among confirmed strokes (p=0.14). The top presenting symptoms among mimics were unilateral weakness (n=8), aphasia (n=6), confusion (n=6), and decreased consciousness (n=6). Nine mimics (25%) received tPA and none had hemorrhagic conversion; while 30 (53%) confirmed strokes received tPA and 2 (7%) had hemorrhagic conversion. There was no difference in MSU arrival-to-tPA time between groups (46 vs. 44 minutes, p=0.70). In multivariable analyses, compared to patients with confirmed stroke, mimics had significantly lower NIHSS scores, higher initial blood pressures, and shorter lengths-of-stay. Rates of death and discharge disposition were similar between groups.

Conclusions: Among patients transported by a MSU for suspected stroke, two-fifths were stroke mimics. Seizure, metabolic encephalopathy, and somatoform disorders were the most common mimic diagnoses. Patients with stroke mimics had lower NIHSS scores and less often were treated with tPA.

Abstract TP153: Cognitive Profile in Patients With Hemodynamic Failure Due to Severe Carotid Stenosis

Background: Severe carotid stenosis can reduce cognition due to hypoperfusion. Published cognitive profiles for vascular disease are variable, however, precluding identification of hemodynamic failure as a specific cause. We investigated the relationship among carotid stenosis, hemodynamic failure, and cognition by characterizing cognition in patients with severe carotid stenosis, with and without hemodynamic failure.

Methods: Sixty-one patients (18 with TIA, none with stroke) with ≥80% carotid stenosis were drawn from two study cohorts, RECON and BFC 1 . Hemodynamic status was assessed using oxygen extraction fraction by positron emission tomography (RECON) or mean flow velocity by transcranial Doppler (BFC) and dichotomized into normal (n=30) vs impaired (n=31). Cognition was assessed with 16 tests. Sixteen linear regressions, one for each cognitive test, were performed to assess the influence of hemodynamic failure on test scores, adjusting for side of occlusion, depression, age, gender, education, and study cohort. Multiple comparisons were adjusted using false discovery rate (FDR) correction.

Results: Hemodynamic failure was a significant independent predictor for Rey Complex Figure Test-Copy (RCFT-C, p=0.007), RCFT-Delayed Recall (RCFT-D, p=0.003), and Trail Making Test-B (TMT-B, p=0.006) and remained so after FDR correction. The other tests were not predicted by hemodynamic status.

Conclusions: Tests of mental flexibility, visuospatial skill, and organization were sensitive to hemodynamic failure in patients with severe carotid stenosis. A larger sample is required to validate this cognitive profile in such patients. Cognitive assessment with RCFT-C, RCFT-D, and TMT-B may detect the effects of hemodynamic failure specific to large vessel disease, having research and treatment utility. 1 NINDS NS048212 (Randomized Evaluation of Carotid Occlusion and Neurocognition -RECON), R01NS076277 (Blood Flow and Cognition - BFC)

Is Hemispheric Hypoperfusion a Treatable Cause of Cognitive Impairment?

PURPOSE OF REVIEW

To review the current literature that supports the notion that cerebral hemodynamic compromise from internal carotid artery stenosis may be a cause of vascular cognitive impairment that is amenable to treatment by revascularization.

RECENT FINDINGS

Converging evidence suggests that successful carotid endarterectomy and carotid artery stenting are associated with reversal of cognitive decline in many patients with severe but asymptomatic carotid artery stenosis. Most of these findings have been derived from cohort studies and comparisons with either normal or surgical controls. Failure to find treatment benefit in a number of studies appears to have been the result of patient heterogeneity or confounding from concomitant conditions independently associated with cognitive decline, such as heart failure and other cardiovascular risk factors, or failure to establish pre-procedure hemodynamic failure. Patients with severe carotid artery stenosis causing cerebral hemodynamic impairment may have a reversible cause of cognitive decline. None of the prior studies, however, were done in the context of a randomized clinical trial with large numbers of participants. The ongoing CREST-2 trial comparing revascularization with medical therapy versus medical therapy alone, and its associated CREST-H study determining whether cognitive decline is reversible among those with hemodynamic compromise may address this question.

Pathological correlates of brain arterial calcifications

BACKGROUND

In clinical practice, calcifications seen on computed tomographic studies within the large brain arteries are often referred to as a surrogate marker for cholesterol-mediated atherosclerosis. However, limited data exist to support the association between calcification and atherosclerosis. In this study, we examined if intracranial arterial calcifications were associated with cholesterol-mediated intracranial large artery atherosclerosis (ILAA) within the arteries of the circle of Willis in an autopsy-based sample.

METHODS

We carried out a cross-sectional analysis of histopathological characteristics of brain large arteries obtained from autopsy cases. Brain large arteries were examined for evidences of calcifications, which were rated as macroscopic (coalescent) and microscopic (scattered). In addition to calcification, we also obtained measurement of the arterial wall and the presence of ILAA and nonatherosclerotic arterial fibrosis. We built hierarchical models adjusted for demographic and vascular risk factors to assess the relationship between calcification and ILAA.

RESULTS

In univariate analysis, the presence of any arterial calcifications was associated with cerebral infarcts (29% vs. 14%, P<.01). Multivariate analysis revealed that among all calcifications, coalescent calcifications were not associated with ILAA. In contrast, scattered calcifications were associated with ILAA (P<.001), decreased lumen diameter (-1.87 +/- 0.41 mm, P≤.001), and increased luminal stenosis (0.03% +/- 0.01%, P≤.006). These findings were independent of age, sex, or other vascular risk factors.

CONCLUSIONS

This study demonstrates that coalescent calcifications in brain large arteries, although associated with morbidity, are not synonymous with cholesterol-driven ILAA. Understanding the precise pathological components of cerebrovascular disease, including nonatherosclerotic arterial calcifications, will help develop individualized therapies beyond amelioration of traditional risk factors such as hyperlipidemia.

Impact of Patient Language on Emergency Medical Service Use and Prenotification for Acute Ischemic Stroke

Background and Purpose

Use of emergency medical services (EMS) is associated with decreased door-to-needle time in acute ischemic stroke (AIS). Whether patient language affects EMS utilization and prenotification in AIS has been understudied. We sought to characterize EMS use and prenotification by patient language among intravenous tissue plasminogen activator (IV-tPA) tissue plasminogen (IV-tPA) treated patients at a single center with a large Spanish-speaking patient population.

Methods

We performed a retrospective analysis of all patients who received IV-tPA in our emergency department between July 2011 and June 2016. Baseline characteristics, EMS use, and prenotification were compared between English- and Spanish-speaking patients. Logistic regression was used to measure the association between patient language and EMS use.

Results

Of 391 patients who received IV-tPA, 208 (53%) primarily spoke English and 174 (45%) primarily spoke Spanish. Demographic and clinical factors including National Institutes of Health Stroke Scale (NIHSS) did not differ between language groups. Emergency medical services use was higher among Spanish-speaking patients (82% vs 70%; P < .01). Prenotification did not differ by language (61% vs 63%; P = .8). In a multivariable model adjusted for age, sex, and NIHSS, Spanish speakers remained more likely to use EMS (odds ratio: 1.8, 95% confidence interval: 1.1-3.0).

Conclusion

Emergency medical services usage was higher in Spanish speakers compared to English speakers among AIS patients treated with IV-tPA; however, prenotification rates did not differ. Future studies should evaluate differences in EMS utilization according to primary language and ethnicity.

Transcranial Doppler Waveforms During Intra-aortic Balloon Pump Counterpulsation for Vasospasm Detection After Subarachnoid Hemorrhage

BACKGROUND

Transcranial Doppler ultrasound is a standard screening tool for vasospasm after subarachnoid hemorrhage. Prevention of vasospasm-induced delayed cerebral ischemia after subarachnoid hemorrhage depends on optimization of cerebral perfusion pressure, which can be challenged by neurogenic stress cardiomyopathy. Intra-aortic balloon pumps have been utilized to augment cerebral perfusion, but they change the transcranial Doppler waveform, altering its interpretability for vasospasm screening.

OBJECTIVE

To assess the features of the transcranial Doppler waveform that correlate with vasospasm.

METHODS

We retrospectively reviewed cases of subarachnoid hemorrhage that underwent same-day transcranial Doppler ultrasound and angiography. Transcranial Doppler waveforms were assessed for mean velocity, peak systolic velocity, balloon pump-augmented diastolic velocity, and a novel feature, "delta velocity" (balloon pump-augmented velocity - systolic velocity). Relationship of flow velocity features to vasospasm was estimated by generalized estimating equation models using a Gaussian distribution and an exchangeable correlation structure.

RESULTS

There were 31 transcranial Doppler and angiography pairings (12 CT angiography/19 digital subtraction angiography) from 4 patients. Fourteen pairings had proximal vasospasm by angiography. Delta velocity was associated with proximal vasospasm (coefficient -6.8 [95% CI -9.8 to -3.8], P < .001). There was no significant correlation with proximal vasospasm for mean velocity (coefficient -13.0 [95% CI -29.3 to 3.4], P = .12), systolic velocity (coefficient -8.7 [95% CI -24.8 to 7.3], P = .29), or balloon pump-augmented velocity (coefficient -15.3 [95% CI -31.3 to 0.71], P = .06).

CONCLUSION

Delta velocity, a novel transcranial Doppler flow velocity feature, may reflect vasospasm in patients with subarachnoid hemorrhage and intra-aortic balloon pumps.

Carotid revascularization and medical management for asymptomatic carotid stenosis - Hemodynamics (CREST-H): Study design and rationale

RATIONALE

For patients with asymptomatic high-grade carotid stenosis, clinical investigations have focused on preventing cerebral infarction, yet stenosis that reduces cerebral blood flow may independently impair cognition. Whether revascularization of a hemodynamically significant carotid stenosis can alter the course of cognitive decline has never been investigated in the context of a randomized clinical trial.

HYPOTHESIS

Among patients randomized in the Carotid Revascularization and Medical Management for Asymptomatic Carotid Stenosis (CREST-2) trials, the magnitude of treatment differences (revascularization versus medical management alone) with regard to cognition will differ between those with flow impairment compared to those without flow impairment.

SAMPLE SIZE

We will enroll approximately 500 patients from CREST-2, of which we anticipate 100 will have hemodynamic impairment. We estimate 93% power to detect a clinically meaningful treatment difference of 0.5 SD.

METHODS AND DESIGN

We will use perfusion-weighted magnetic resonance imaging to stratify by hemodynamic status. Linear regression will compare treatment differences, controlling for baseline cognitive status, age, depression, prior cerebral infarcts, silent infarction, white matter hyperintensity volume, and cerebral microbleeds.

STUDY OUTCOMES

The primary outcome is change in cognition at one year. Secondary outcomes include silent infarction, change in white matter hyperintensity volume, number of cerebral microbleeds, and cortical thickness over one year.

DISCUSSION

If cognitive impairment can be shown to be reversible by revascularization, then we can redefine "symptomatic carotid stenosis" to include cognitive impairment and identify a new population of patients likely to benefit from revascularization.

TRIAL REGISTRATION

US National Institutes of Health (NIH) clinicaltrials.gov NCT03121209.

Perfusion imaging and recurrent cerebrovascular events in intracranial atherosclerotic disease or carotid occlusion

Background

Large vessel disease stroke subtype carries the highest risk of early recurrent stroke. In this study we aim to look at the association between impaired perfusion and early stroke recurrence in patients with intracranial atherosclerotic disease or total cervical carotid occlusion.

Methods

This is a retrospective study from a comprehensive stroke center where we included consecutive patients 18 years or older with intracranial atherosclerotic disease or total cervical carotid occlusion admitted with a diagnosis of ischemic stroke within 24 h from symptom onset with National Institute Health Stroke Scale < 15, between 1 December 2016 and 30 June 2017. Patients with (1) evidence of ≥ 50% stenosis of a large intracranial artery or total carotid artery occlusion, (2) symptoms referable to the territory of the affected artery, and (3) perfusion imaging data using the RAPID processing software were included. The primary predictor was unfavorable perfusion imaging defined as Tmax > 6 s mismatch volume (penumbra volume–infarct volume) of 15 ml or more. The outcome was recurrent cerebrovascular events at 90 days defined as worsening or new neurological symptoms in the absence of a nonvascular cause attributable to the decline, or new infarct or infarct extension in the territory of the affected artery. We used Cox proportional hazards models to determine the association between impaired perfusion and recurrent cerebrovascular events.

Results

Sixty-two patients met our inclusion criteria; mean age 66.4 ± 13.1 years, 64.5% male (40/62) and 50.0% (31/62) with intracranial atherosclerotic disease. When compared to patients with favorable perfusion pattern, patients with unfavorable perfusion pattern were more likely to have recurrent cerebrovascular events (55.6% (10/18) versus 9.1% (4/44), p < 0.001). This association persisted after adjusting for potential confounders (adjusted hazard ratio 10.44, 95% confidence interval 2.30–47.42, p = 0.002).

Conclusion

Perfusion mismatch predicts recurrent cerebrovascular events in patients with ischemic stroke due to intracranial atherosclerotic disease or total cervical carotid occlusion. Studies are needed to determine the utility of revascularization strategies in this patient population.

Clinical Information Systems Integration in New York City's First Mobile Stroke Unit

BACKGROUND

Mobile stroke units (MSUs) reduce time to thrombolytic therapy in acute ischemic stroke. These units are widely used, but the clinical information systems underlying MSU operations are understudied.

OBJECTIVE

The first MSU on the East Coast of the United States was established at New York Presbyterian Hospital (NYP) in October 2016. We describe our program's 7-month pilot, focusing on the integration of our hospital's clinical information systems into our MSU to support patient care and research efforts.

METHODS

NYP's MSU was staffed by two paramedics, one radiology technologist, and a vascular neurologist. The unit was equipped with four laptop computers and networking infrastructure enabling all staff to access the hospital intranet and clinical applications during operating hours. A telephone-based registration procedure registered patients from the field into our admit/discharge/transfer system, which interfaced with the institutional electronic health record (EHR). We developed and implemented a computerized physician order entry set in our EHR with prefilled values to permit quick ordering of medications, imaging, and laboratory testing. We also developed and implemented a structured clinician note to facilitate care documentation and clinical data extraction.

RESULTS

Our MSU began operating on October 3, 2016. As of April 27, 2017, the MSU transported 49 patients, of whom 16 received tissue plasminogen activator (t-PA). Zero technical problems impacting patient care were reported around registration, order entry, or intranet access. Two onboard network failures occurred, resulting in computed tomography scanner malfunctions, although no patients became ineligible for time-sensitive treatment as a result. Thirteen (26.5%) clinical notes contained at least one incomplete time field.

CONCLUSION

The main technical challenges encountered during the integration of our hospital's clinical information systems into our MSU were onboard network failures and incomplete clinical documentation. Future studies are necessary to determine whether such integrative efforts improve MSU care quality, and which enhancements to information systems will optimize clinical care and research efforts.

Abstract TMP17: Impaired Perfusion Imaging Predicts Recurrent Cerebrovascular Events in Symptomatic Large Vessel Stenosis

Importance: Large vessel disease (LVD) stroke subtype carries the highest risk of early recurrent stroke, reaching up to 30% in the first few days. Predictors of early recurrence have been previously described, but less is known regarding infarct expansion and other causes of neurological worsening. We aim to determine the association between impaired perfusion and neurological decline in patients with LVD subtype.

Methods: This is a single center retrospective cohort study of all consecutive patients 18 years or older with LVD admitted with a diagnosis of ischemic stroke within 24 hours from symptom onset (12/1/2016 to 3/31/2017). Patients with 1) evidence of ≥ 50% stenosis of a large intra- or extracranial artery on computerized tomography angiography (CTA); 2) symptoms referable to the territory of the affected artery and NIHSS < 15 and 3) perfusion imaging data using the RAPID processing software were included. The primary predictor was unfavorable mismatch volume ≥15 mL, defined as perfusion deficit of Tmax > 6sec volume minus infarct volume similar to neuro-interventional trials. The outcome was recurrent cerebrovascular events (RCVE) at 90 days (adjudicated independently by two vascular neurologists) defined as a decline in neurologic function in the absence of a medical cause, or new infarct or infarct extension in the territory of the affected artery. We estimated the hazard ratio (HR) and 95% confidence interval (CI) for unfavorable perfusion imaging as predictor of RCVE using univariable and multivariable Cox proportional hazards models.

Results: Sixty-eight patients met our inclusion criteria (mean age 64.7 years; 61.8% male; 58.8% intracranial LVD). When compared to patients without RCVE, patients with RCVE were more likely to have unfavorable mismatch volume [71.4% vs. 14.8%, p<0.001]. This association persisted after adjusting for sex, dual antiplatelet therapy, initial stroke severity, and intracranial location of LVD (adjusted HR 15.6, 95% CI 3.7-66.7, p<0.001).

Conclusion: Perfusion mismatch is associated with RCVE in patients with ischemic stroke due to LVD. Pursuit of more aggressive treatment and management strategies may be warranted in this population.