Radiological examination of the brain is a critical determinant of stroke care pathways. Accessible neuroimaging is essential to detect the presence of intracerebral hemorrhage (ICH). Conventional ...magnetic resonance imaging (MRI) operates at high magnetic field strength (1.5-3 T), which requires an access-controlled environment, rendering MRI often inaccessible. We demonstrate the use of a low-field MRI (0.064 T) for ICH evaluation. Patients were imaged using conventional neuroimaging (non-contrast computerized tomography (CT) or 1.5/3 T MRI) and portable MRI (pMRI) at Yale New Haven Hospital from July 2018 to November 2020. Two board-certified neuroradiologists evaluated a total of 144 pMRI examinations (56 ICH, 48 acute ischemic stroke, 40 healthy controls) and one ICH imaging core lab researcher reviewed the cases of disagreement. Raters correctly detected ICH in 45 of 56 cases (80.4% sensitivity, 95%CI: 0.68-0.90). Blood-negative cases were correctly identified in 85 of 88 cases (96.6% specificity, 95%CI: 0.90-0.99). Manually segmented hematoma volumes and ABC/2 estimated volumes on pMRI correlate with conventional imaging volumes (ICC = 0.955, p = 1.69e-30 and ICC = 0.875, p = 1.66e-8, respectively). Hematoma volumes measured on pMRI correlate with NIH stroke scale (NIHSS) and clinical outcome (mRS) at discharge for manual and ABC/2 volumes. Low-field pMRI may be useful in bringing advanced MRI technology to resource-limited settings.
Epigenetics refers to chromatin-based pathways important in the regulation of gene expression and includes 3 distinct, but highly interrelated, mechanismsDNA methylation, histone density and ...posttranslational modifications, and RNA-based mechanisms. Together, they offer a newer perspective on transcriptional control paradigms in vascular endothelial cells and provide a molecular basis for how the environment impacts the genome to modify disease susceptibility. This review provides an introduction to epigenetic concepts for vascular biologists. Using endothelial nitric oxide synthase (NOS3) as an example, we examine the growing body of evidence implicating epigenetic pathways in the control of vascular endothelial gene expression in health and disease.
Flow diversion for posterior circulation aneurysms performed using the Pipeline embolization device (PED) constitutes an increasingly common off-label use for otherwise untreatable aneurysms. The ...safety and efficacy of this treatment modality has not been assessed in a multicenter study.
A retrospective review of prospectively maintained databases at 8 academic institutions was performed for the years 2009 to 2016 to identify patients with posterior circulation aneurysms treated with PED placement.
A total of 129 consecutive patients underwent 129 procedures to treat 131 aneurysms; 29 dissecting, 53 fusiform, and 49 saccular lesions were included. At a median follow-up of 11 months, complete and near-complete occlusion was recorded in 78.1%. Dissecting aneurysms had the highest occlusion rate and fusiform the lowest. Major complications were most frequent in fusiform aneurysms, whereas minor complications occurred most commonly in saccular aneurysms. In patients with saccular aneurysms, clopidogrel responders had a lower complication rate than did clopidogrel nonresponders. The majority of dissecting aneurysms were treated in the immediate or acute phase following subarachnoid hemorrhage, a circumstance that contributed to the highest mortality rate in those aneurysms.
In the largest series to date, fusiform aneurysms were found to have the lowest occlusion rate and the highest frequency of major complications. Dissecting aneurysms, frequently treated in the setting of subarachnoid hemorrhage, occluded most often and had a low complication rate. Saccular aneurysms were associated with predominantly minor complications, particularly in clopidogrel nonresponders.
IMPORTANCE: Unruptured intracranial aneurysms (UIAs) are relatively common in the general population and are being increasingly diagnosed; a significant proportion are tiny (≤3 mm) aneurysms. There ...is significant heterogeneity in practice and lack of clear guidelines on the management of incidental, tiny UIAs. It is important to quantify the implications of different management strategies in terms of health benefits to patients. OBJECTIVE: To evaluate the effectiveness of routine treatment (aneurysm coiling) vs 3 strategies for imaging surveillance compared with no preventive treatment or routine follow-up of tiny UIAs. DESIGN, SETTING, AND PARTICIPANTS: A decision-analytic model-based comparative effectiveness analysis was conducted from May 1 to June 30, 2017, using inputs from the medical literature. PubMed searches were performed to identify relevant literature for all key model inputs, each of which was derived from the clinical study with the most robust data and greatest applicability. Analysis included 10 000 iterations simulating adult patients with incidental detections of UIAs 3 mm or smaller and no history of subarachnoid hemorrhage. INTERVENTIONS: The following 5 management strategies for tiny UIAs were evaluated: annual magnetic resonance angiography (MRA) screening, biennial MRA screening, MRA screening every 5 years, aneurysm coiling and follow-up, and no treatment or preventive follow-up. MAIN OUTCOMES AND MEASURES: A Markov decision model for lifetime rupture was constructed from a societal perspective per 10 000 patients with incidental, tiny UIAs. Outcomes were assessed in terms of quality-adjusted life-years. Probabilistic, 1-way, and 2-way sensitivity analyses were performed. RESULTS: In this analysis of 10 000 iterations simulating adult patients with a mean age of 50 years, the base-case calculation shows that the management strategy of no treatment or preventive follow-up has the highest health benefit (mean SD quality-adjusted life-years, 19.40 0.31). Among the management strategies that incorporate follow-up imaging, MRA every 5 years is the best strategy with the next highest effectiveness (mean SD quality-adjusted life-years, 18.05 0.62). The conclusion remains robust in probabilistic and 1-way sensitivity analyses. No routine follow-up remains the optimal strategy when the annual growth rate and risk of rupture of growing aneurysms are varied. When the annual risk of rupture of nongrowing UIAs is less than 1.7% (0.23% in base case scenario), no follow-up is the optimal strategy. If annual risk of rupture is more than 1.7%, coiling should be performed directly. CONCLUSIONS AND RELEVANCE: Given the current literature, no preventive treatment or imaging follow-up is the most effective strategy in patients with aneurysms that are 3 mm or smaller, resulting in better health outcomes. More aggressive imaging surveillance for aneurysm growth or preventive treatment should be reserved for patients with a high risk of rupture. Given these findings, it is important to critically evaluate the appropriateness of current clinical practices, and potentially determine specific guidelines to reflect the most effective management strategy for patients with incidental, tiny UIAs.
Background
Triage for suspected acute stroke has two main options: (1) transport to the closest primary stroke center (PSC) and then to the nearest comprehensive stroke center (CSC) (Drip-and-Ship) ...or (2) transport the patient to the nearest CSC, bypassing a closer PSC (mothership). The purpose was to evaluate the effectiveness of drip-and-ship versus mothership models for acute stroke patients.
Methods
A Markov decision-analytic model was constructed. All model parameters were derived from recent medical literature. Our target population was adult patient with sudden onset of acute stroke within 8 h of onset over a one-year horizon. The primary outcome was quantified in terms of quality-adjusted-life-years (QALYs).
Results
The base case scenario show that the drip-and-ship strategy has a slightly higher expected health benefit, 0.591 QALY, as compared to 0.586 QALY in the mothership strategy when the time to PSC is 30 min and to CSC is 65 min, although the difference in health benefit becomes minimal as the time to PSC increases towards 60 min. Multiple sensitivity analyses show that when both PSC and CSC are far from place of onset (>1.5 h away), drip-and-ship becomes the better strategy. Mothership strategy is favored by smaller difference between distances to PSC and CSC, shorter transfer time from PSC to CSC, and longer delay in reperfusion in CSC for transferred patients. Drip-and-ship is favored by the reverse.
Conclusion
Drip-and-ship has a slightly higher utility than mothership. This study assesses the complex issue of prehospital triage of acute stroke patients and can provide a framework for real-world data input.
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NUK, OILJ, SAZU, UKNU, UL, UM, UPUK
Both endovascular coiling and the Pipeline embolization device (PED) have been shown to be safe and clinically effective for treatment of small (< 10 mm) aneurysms. The authors conducted a ...comparative effectiveness analysis to compare the utility of these treatment methods in terms of health benefits.
A decision-analytical study was performed with Markov modeling methods to simulate patients with small unruptured aneurysms undergoing endovascular coiling, stent-assisted coiling (SAC), or PED placement for treatment. Input probabilities were derived from prior literature, and 1-way, 2-way, and probabilistic sensitivity analyses were performed to assess model and input parameter uncertainty.
The base case calculation for a 50-year-old man reveals PED to have a higher health benefit (17.48 quality-adjusted life years QALYs) than coiling (17.44 QALYs) or SAC (17.36 QALYs). PED is the better option in 6020 of the 10,000 iterations in probabilistic sensitivity analysis. When the retreatment rate of PED is lower than 9.53%, and the coiling retreatment is higher than 15.6%, PED is the better strategy. In the 2-way sensitivity analysis varying the retreatment rates from both treatment modalities, when the retreatment rate of PED is approximately 14% lower than the retreatment rate of coiling, PED is the more favorable treatment strategy. Otherwise, coiling is more effective. SAC may be better than PED when the unfavorable outcome risk of SAC is lower than 70% of its reported current value.
With the increasing use of PEDs for treatment of small unruptured aneurysms, the current study indicates that these devices may have higher health benefits due to lower rates of retreatment compared to both simple coiling and stent-assisted techniques. Longer follow-up studies are needed to document the rates of recurrence and retreatment after coiling and PED to assess the cost-effectiveness of these strategies.
BACKGROUND AND PURPOSE—Multiple studies have shown that negative computed tomographic angiograms (CTAs) are reliable in excluding aneurysms in patients with isolated perimesencephalic subarachnoid ...hemorrhage (pSAH). We evaluate the use of digital subtraction angiography versus CTA for initial diagnosis and of angiographic follow-ups in patients with pSAH by performing an institutional analysis and a meta-analysis of literature.
METHODS—Retrospective institutional analysis of patients with pSAH was performed from 2008 to 2014. The number and types of follow-up imaging studies were tabulated. Initial and follow-up studies were evaluated by an experienced neuroradiologist for intracranial aneurysm. Meta-analysis of literature was performed to assess the use of initial digital subtraction angiography and of follow-up imaging.
RESULTS—Our institutional review revealed no additional use of initial digital subtraction angiography or of any angiographic follow-up after initial negative CTA in patients with pSAH on noncontrast CT. Meta-analysis of 40 studies yielded a total of 1031 patients. Only 8 aneurysms were first diagnosed on follow-ups (0.78%). Careful review showed that some of these aneurysms reported on follow-up are of questionable validity. Initial digital subtraction angiography and follow-up imaging after a negative initial CTA showed no statistically significant benefits.
CONCLUSIONS—In patients meeting the strict imaging criteria of pSAH, initial negative CTA is reliable in excluding aneurysms. A critical review of the literature through meta-analysis shows no foundation for multiple follow-up studies in patients with pSAH.
BACKGROUND AND PURPOSE—Loss of cerebral autoregulation in the acute phase of ischemic stroke leaves patients vulnerable to blood pressure (BP) changes. Effective BP management after endovascular ...thrombectomy may protect the brain from hypoperfusion or hyperperfusion. In this observational study, we compared personalized, autoregulation-based BP targets to static systolic BP thresholds.
METHODS—We prospectively enrolled 90 patients undergoing endovascular thrombectomy for stroke. Autoregulatory function was continuously measured by interrogating changes in near-infrared spectroscopy–derived tissue oxygenation (a cerebral blood flow surrogate) in response to changes in mean arterial pressure. The resulting autoregulatory index was used to trend the BP range at which autoregulation was most preserved. Percent time that mean arterial pressure exceeded the upper limit of autoregulation or decreased below the lower limit of autoregulation was calculated for each patient. Time above fixed systolic BP thresholds was computed in a similar fashion. Functional outcome was measured with the modified Rankin Scale at 90 days.
RESULTS—Personalized limits of autoregulation were successfully computed in all 90 patients (age 71.6±16.2, 47% female, mean National Institutes of Health Stroke Scale 13.9±5.7, monitoring time 28.0±18.4 hours). Percent time with mean arterial pressure above the upper limit of autoregulation associated with worse 90-day outcomes (odds ratio per 10% 1.84 95% CI, 1.3–2.7 P=0.002), and patients with hemorrhagic transformation spent more time above the upper limit of autoregulation (10.9% versus 16.0%, P=0.042). Although there appeared to be a nonsignificant trend towards worse outcome with increasing time above systolic BP thresholds of 140 mm Hg and 160 mm Hg, the effect sizes were smaller compared with the personalized approach.
CONCLUSIONS—Noninvasive determination of personalized BP thresholds for stroke patients is feasible. Deviation from these limits may increase risk of further brain injury and poor functional outcome. This approach may present a better strategy compared with the classical approach of maintaining systolic BP below a predetermined value, though a randomized trial is needed to determine the optimal approach for hemodynamic management.
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