Prospective study examining the impact of cerebral angiography on quantitative pupillometer values in the interventional radiology suite.

OBJECTIVES: The purpose of this pilot study was to obtain baseline quantitative pupillometry (QP) measurements before and after catheter-directed cerebral angiography (DCA) to explore the hypothesis that cerebral angiography is an independent predictor of change in pupillary light reflex (PLR) metrics. DESIGN: This was a prospective, observational pilot study of PLR assessments obtained using QP 30 min before and after DCA. All patients had QP measurements performed with the NPi-300 (Neuroptics) pupillometer. SETTING: Recruitment was done at a single-centre, tertiary-care academic hospital and comprehensive stroke centre in Dallas, Texas. PARTICIPANTS: Fifty participants were recruited undergoing elective or emergent angiography. Inclusion criteria were a physician-ordered interventional neuroradiological procedure, at least 18 years of age, no contraindications to PLR assessment with QP, and nursing transport to and from DCA. Patients with a history of eye surgery were excluded. MAIN OUTCOME MEASURES: Difference in PLR metric obtained from QP 30 min before and after DCA. RESULTS: Statistically significant difference was noted in the pre and post left eye readings for the minimum pupil size (a.k.a., pupil diameter on maximum constriction). The mean maximum constriction diameter prior to angiogram of 3.2 (1.1) mm was statistically larger than after angiogram (2.9 (1.0) mm; p<0.05); however, this was not considered clinically significant. Comparisons for all other PLR metrics pre and post angiogram demonstrated no significant difference. Using change in NPi pre and post angiogram (Δpre=0.05 (0.77) vs Δpost=0.08 (0.67); p=0.62), we calculated the effect size as 0.042. Hence, detecting a statistically significant difference in NPi, if a difference exists, would require a sample size of ~6000 patients. CONCLUSIONS: Our study provides supportive data that in an uncomplicated angiogram, even with intervention, there is no effect on the PLR.

Strokes and Predictors of Outcomes.

Stroke is a leading cause of long-term disability and fifth leading cause of death. Acute ischemic stroke, intracerebral hemorrhage, and subarachnoid hemorrhage, the 3 subtypes of strokes, have varying treatment modalities. Common themes in management advocate for early interventions to reduce morbidity and mortality but not all perception is supported through randomized controlled trials. Each stroke subtype has varying premorbid-related and ictus-related outcome predictive models that have differing sensitivities and specificities.

Scoring System to Predict Hospital Outcome After Subarachnoid Hemorrhage-Incorporating Systemic Response: The CRIG Score.

OBJECTIVES: Local and systemic proinflammatory and prothrombotic processes after aneurysmal subarachnoid hemorrhage (aSAH) precipitate delayed cerebral ischemia (DCI) and determine clinical outcome. Recent studies using admission and temporal trends of mean platelet volume to platelet count ratio (MPV:PLT) and neutrophil to lymphocyte ratio (NLR) have identified patients developing DCI. We examine if MPV:PLT and NLR along with admission clinical or radiological features can be used to develop a scoring system to predict DCI and in-hospital clinical outcome. MATERIALS AND METHODS: A 7-year retrospective cohort of aSAH patients admitted to a tertiary care medical center was used to study and identify clinical, radiological and laboratory parameters to predict DCI and clinical outcome (good: discharge to home or rehabilitation facility; poor: all other discharge destinations). Using regression analyses a scoring system (Clinical, Radiological, Inflammatory, dysGlycemia, CRIG) was developed. RESULTS: Of 271 patients, admission clinical grade (World Federation of Neurological Surgeons' scale), radiological grade (modified Fisher score), NLR and glycated hemoglobin were identified as contributors for CRIG score. CRIGDCI score threshold of 112 and CRIGdischarge 109, respectively predicted DCI and adverse clinical outcome in score development cohort. The same threshold predicted DCI and adverse clinical outcome with 78.1 and 100% sensitivity, 44.0 and 52.2% specificity, and 63.2 and 61.4% accuracy, respectively in the score validation cohort. CONCLUSIONS: CRIG is an easily calculable scoring system that incorporates systemic response of aSAH - thus, alluding to its multisystem nature. It can be used at the time of admission to predict DCI and clinical outcome.

Developing new quantitative CT image markers to predict prognosis of acute ischemic stroke patients.

BACKGROUND: Endovascular mechanical thrombectomy (EMT) is an effective method to treat acute ischemic stroke (AIS) patients due to large vessel occlusion (LVO). However, stratifying AIS patients who can and cannot benefit from EMT remains a clinical challenge. OBJECTIVE: To develop a new quantitative image marker computed from pre-intervention computed tomography perfusion (CTP) images and evaluate its feasibility to predict clinical outcome among AIS patients undergoing EMT after diagnosis of LVO. METHODS: A retrospective dataset of 31 AIS patients with pre-intervention CTP images is assembled. A computer-aided detection (CAD) scheme is developed to pre-process CTP images of different scanning series for each study case, perform image segmentation, quantify contrast-enhanced blood volumes in bilateral cerebral hemispheres, and compute features related to asymmetrical cerebral blood flow patterns based on the cumulative cerebral blood flow curves of two hemispheres. Next, image markers based on a single optimal feature and machine learning (ML) models fused with multi-features are developed and tested to classify AIS cases into two classes of good and poor prognosis based on the Modified Rankin Scale. Performance of image markers is evaluated using the area under the ROC curve (AUC) and accuracy computed from the confusion matrix. RESULTS: The ML model using the neuroimaging features computed from the slopes of the subtracted cumulative blood flow curves between two cerebral hemispheres yields classification performance of AUC = 0.878±0.077 with an overall accuracy of 90.3%. CONCLUSIONS: This study demonstrates feasibility of developing a new quantitative imaging method and marker to predict AIS patients' prognosis in the hyperacute stage, which can help clinicians optimally treat and manage AIS patients.

Applying Quantitative Radiographic Image Markers to Predict Clinical Complications After Aneurysmal Subarachnoid Hemorrhage: A Pilot Study.

Accurately predicting clinical outcome of aneurysmal subarachnoid hemorrhage (aSAH) patients is difficult. The purpose of this study was to develop and test a new fully-automated computer-aided detection (CAD) scheme of brain computed tomography (CT) images to predict prognosis of aSAH patients. A retrospective dataset of 59 aSAH patients was assembled. Each patient had 2 sets of CT images acquired at admission and prior-to-discharge. CAD scheme was applied to segment intracranial brain regions into four subregions, namely, cerebrospinal fluid (CSF), white matter (WM), gray matter (GM), and leaked extraparenchymal blood (EPB), respectively. CAD then detects sulci and computes 9 image features related to 5 volumes of the segmented sulci, EPB, CSF, WM, and GM and 4 volumetrical ratios to sulci. Subsequently, applying a leave-one-case-out cross-validation method embedded with a principal component analysis (PCA) algorithm to generate optimal feature vector, 16 support vector machine (SVM) models were built using CT images acquired either at admission or prior-to-discharge to predict each of eight clinically relevant parameters commonly used to assess patients' prognosis. Finally, a receiver operating characteristics (ROC) method was used to evaluate SVM model performance. Areas under ROC curves of 16 SVM models range from 0.62 ± 0.07 to 0.86 ± 0.07. In general, SVM models trained using CT images acquired at admission yielded higher accuracy to predict short-term clinical outcomes, while SVM models trained using CT images acquired prior-to-discharge demonstrated higher accuracy in predicting long-term clinical outcomes. This study demonstrates feasibility to predict prognosis of aSAH patients using new quantitative image markers generated by SVM models.

Quantitative Analysis of Stress-Induced Hyperglycemia and Intracranial Blood Volumes for Predicting Mortality After Intracerebral Hemorrhage.

Stress-induced hyperglycemia (SIH) is a neuroendocrine response to acute illness. Although SIH has an adverse association with intracerebral hemorrhage (ICH), quantitative measures and determinants of SIH are not well delineated. In the present study, we objectively evaluated SIH using glycemic gap (GG) and identified its radiological and clinical determinants, with a 5-year retrospective review of charts of ICH patients. We calculated GG using the regression equation (GG = AG -28.7 × HbA1c + 46.7) and evaluated whether GG is an independent predictor of mortality using a multivariate regression model. Radiological volumes of different intracranial compartments were determined using image segmentation software. We correlated GG with different clinical and radiological parameters using Pearson correlation coefficient (PCC), Spearman's rank correlation (SRC), and Wilcoxon rank sum test. Then, we calculated the value of GG associated with mortality. Out of 328 patients, 238 (73%) survived hospitalization and 90 (27%) expired. GG was found to be an independent predictor of mortality (r=0.008, p=0.04). Additionally, GG was positively correlated with intraparenchymal hemorrhage (IPH) volume (PCC=0.185, p<0.01) and intraventricular hemorrhage (IVH) volume (PCC=0.233, p<0.01) and negatively correlated with cerebrospinal fluid (CSF) volume (PCC=-0.151, p<0.01) and brain tissue volume (PCC=-0.099, p=0.08). GG was positively correlated with patients' ICH score (SRC=0.377, p<0.01), Glasgow Coma Scale (GCS) (PCC=-0.356, p<0.01), hydrocephalus (p<0.01), and IVH in the third ventricle (p<0.01). The univariate logistic regression model identified 30.0 mg/dl as the value of GG (AUC=0.655, p<0.01) that predicted mortality with 52.2% sensitivity and 75.2% specificity and defined SIH. In conclusion, GG independently predicts mortality in ICH patients and positively correlates with IPH and IVH volumes. However, causality between the two is not established and would require specifically designed studies.

Cryptococcal Meningoencephalitis During Convalescence From Severe COVID-19 Pneumonia.

Invasive cryptococcal infection in a previously immunocompetent patient complicating coronavirus disease 2019 (COVID-19) pneumonia has not been described before. In this report, a 76-year-old woman survived a bout of respiratory failure from severe COVID-19 pneumonia, during which she received remdesivir, convalescent plasma, corticosteroids, and tocilizumab. Soon after discharge, she developed acute encephalopathy and multifocal ischemic strokes. CSF and blood cultures were positive for Cryptococcus neoformans. Cryptococcal meningoencephalitis should be considered in the differential diagnosis of encephalopathy in a patient with COVID-19. Treatment with high-dose steroids and tocilizumab may be predisposing factors.

Refractory Heparin-Induced Thrombocytopenia in a Patient With Subarachnoid Hemorrhage-A Clinical Conundrum.

Heparin induced thrombocytopenia (HIT) often resolves with discontinuation of heparin/ heparinoid products. Severe HIT with platelet counts <20,000/µL and disseminated intravascular coagulation is frequently associated with consumptive coagulopathy and systemic thrombosis. Management of severe HIT in patients who fail to improve on discontinuing heparinoid products and argatroban infusion is not well established. We describe a patient admitted with aneurysmal subarachnoid hemorrhage (SAH) who developed severe autoimmune HIT, failed conventional anticoagulation therapy with argatroban and progressed to develop extensive deep venous thrombosis and limb ischemia. She was successfully treated using bivalirudin, immunomodulation with 2 cycles of intravenous immunoglobulin and immunosuppression with methylprednisolone. Refractory severe HIT among SAH patients is rare and pose several therapeutic challenges. We report successful treatment using alternate anticoagulant and immune suppression and modulation.

Criteria for Emergency Brain MRI During Stroke-Alert.

OBJECTIVES: Intravenous (IV) tissue plasminogen activator (tPA) should be given to patients with acute ischemic stroke (AIS) and avoided in stroke mimics (SM). Select use of emergency brain magnetic resonance imaging (eMRI-brain) in stroke-alerts aids diagnosis, but accepted utilization criteria for eMRI-brain do not currently exist. We developed criteria for eMRI-brain and report the yield of eMRI-brain in stroke-alert patients. MATERIALS AND METHODS: We developed three history-based criteria for performing eMRI-brain during stroke-alerts: (1) history of previous similar deficits, (2) change in consciousness at onset of symptoms, (3) symptom presentation consistent with migraine aura. We then performed a retrospective chart review of patients who presented as a stroke-alert over a 5-year period and determined how these criteria affected administration of IV tPA to AIS and SM patients. RESULTS: Among 3,512 stroke-alerts, 230 (8.1%) patients met our criteria for eMRI-brain exams: 217 (92.6%) had SM and 17 (7.4%) had AIS. Our IV tPA decision-making analysis showed that based on eMRI-brain IV tPA was less frequently administered to SM patients (PCC-0.841, p=0.036) with less failures to administer IV tPA to patients with AIS (PCC -0.907, p-value=0.013, Pearson correlation coefficient). No patients became ineligible for IV tPA due to MRI-related time delays. CONCLUSIONS: Our history based criteria for performing eMRI-brain during stroke-alerts show a high yield of stroke mimics. Selective eMRI-brain improves decision-making accuracy regarding IV tPA administration.

Novel Metabolites as Potential Indicators of Ischemic Infarction Volume: a Pilot Study.

Metabolomics may identify biomarkers for acute ischemic stroke (AIS). Previously, circulating metabolites were compared in AIS and healthy controls without accounting for stroke size. The goal of this study was to identify metabolites that associate with the volume of AIS. We prospectively analyzed 1554 serum metabolites in the acute (72 h) and chronic (3-6 months) stages of 60 ischemic stroke patients. We calculated infarct volume using diffusion-weighted images with MR segmentation software and associated the volume with stage-specific metabolites, acute-to-chronic stage changes, and multiple mixed regression in metabolite concentrations using multivariate regression analysis. We used the two-stage Benjamini and Hochberg (TSBH) procedure for multiple testing. Four unknown metabolites at the acute stage significantly associated with infarct volume: X24541, X24577, X24581, and X2482 (all p < 0.01). Nine metabolites at the chronic stage are significantly associated with infarct volume: indolpropinate, alpha ketoglutaramate, picolinate, X16087, X24637, X24576, X24577, X24582, X24581 (all p < 0.048). Infarct volume is also associated with significant changes in serum concentrations of twenty-seven metabolites, with p values from 0.01 to 1.48 × 10-7, and on five metabolites using mixed regression model. This prospective pilot study identified several metabolites associated with the volume of ischemic infarction. Confirmation of these findings on a larger dataset would help characterize putative pathways underlying the size of ischemic infarction and facilitate the identification of biomarkers or therapeutic targets.

Management of Aneurysmal Subarachnoid Hemorrhage: Variation in Clinical Practice and Unmet Need for Follow-up among Survivors-A Single-Center Perspective.

OBJECTIVE: The purpose of the present study is to investigate the existence and/or prevalence of clinical practice variation in management of aneurysmal subarachnoid hemorrhage (aSAH) and to determine the need for long-term follow-up. METHODS: A single-center study was carried out of patients with aSAH over a 5-year period divided into 2 halves (2.5 years each) before and after addition of a dually trained cerebrovascular neurosurgeon. In-hospital clinical practice, clinical outcome (mortality and discharge destination) and long-term outcome (modified Rankin Scale score and Telephone Interview for Cognitive Status [TICS]) were compared using descriptive summaries and nonparametric tests. RESULTS: Among 251 patients admitted with aSAH, 115 (45.8%) were before the index event, whereas 136 (54.2%) were during the later period. The aneurysm-securing procedure changed from coil embolization to clip ligation (12/115 [10.4%] vs. 84/136 [61.8%]; P < 0.0001) during the latter years. Interventional treatment for cerebral vasospasm has decreased (58/115 [50.4%] vs. 49/136 [36.0%]; P = 0.0002). Patients surviving hospitalization had more clinic follow-up after discharge during the latter period (42/85 [49.4%] vs. 76/105 [72.4%]; P = 0.0012) and ventriculoperitoneal shunt placement for delayed hydrocephalus (1/85 [1.2%] vs. 9/105 [8.6%]; P = 0.02). A subcohort of aSAH survivors (n = 46) had lower median TICS score during the earlier study period (31.5 [interquartile range, 22-36] vs. 33 [interquartile range, 27-38]; P = 0.038). Similarly, preictal smoking status and hyperlipidemia were associated with adverse TICS score in a multivariate model (P = 0.007). CONCLUSIONS: Postdischarge clinical follow-up has improved facilitating recognition and treatment of delayed hydrocephalus. Existence of cognitive deficits among survivors calls for establishment of multidisciplinary clinics for long-term management of aSAH.

Potential Metabolite Biomarkers for Acute Versus Chronic Stage of Ischemic Stroke: A Pilot Study.

BACKGROUND: Metabolome profiling is used to identify biomarkers for acute ischemic stroke (AIS). Previous studies compared metabolite profiles in AIS and healthy controls, which did not account for factors that affect metabolome (genetics, medications). This pilot project evaluates the change in metabolite concentrations between the acute and chronic stage of stroke in the same cohort in order to minimize other factors impact. METHODS: We performed global metabolome profile on serum of 20 and urine of 12 stroke patients in acute (72 hours) and chronic (3-5.2 months) stage and compared relative peak values using Wilcoxon and orthogonal partial least squares discriminant analysis methods. Chronic stage metabolite concentrations were considered baseline. We performed analysis to identify significantly overrepresented pathways using MetaboAnalyst. RESULTS: Three serum metabolites asparagine (P = .045), tyrosine (P = .015), and xylose (P = .003) had significantly higher concentrations in acute stage. Seven out of top 10 serum metabolites ranked by Wilcoxon test P value were related to amino acid (AA) metabolism. Two urine metabolites glycine (P = .03) and acetylcarnitine (P = .05) had significantly different concentrations in the acute stage. Five of the top 10 urine metabolites related to AA metabolism. We identified 6 significant pathways after false discovery rate correction that were upregulated in the acute stage: (1) Aminoacyl-tRNA synthesis, (2) nitrogen, (3) alanine, aspartate, and glutamate, (4) branched-chain AA, (5) arginine and proline, and (6) phenylalanine metabolism. CONCLUSION: Longitudinal study design confirms that AA metabolism heavily involved in the pathophysiology of acute brain ischemia. Prospective longitudinal studies with a higher number of participants are needed to establish useful stroke biomarkers.

Predicting Clinical Outcome After Mechanical Thrombectomy: The GADIS (Gender, Age, Diabetes Mellitus History, Infarct Volume, and Current Smoker [corrected]) Score.

OBJECTIVE: To investigate predictive factors and develop an outcome assessment tool to determine clinical outcome after endovascular mechanical thrombectomy (EMT) in patients presenting with large vessel occlusion (LVO). METHODS: A retrospective analysis was carried out of a prospective cohort of patients presenting with LVO who underwent EMT after adoption of an expanded time window of ≤24 hours. Final cerebral infarction volume (CIV) after EMT was estimated using magnetic resonance imaging segmentation software. Stepwise linear regression models were used to identify factors that determined clinical outcome and to develop a predictive scale. RESULTS: Ninety patients underwent EMT over 19 months (68 within 6 hours and 22 between 6 and 24 hours). Clinical outcome determined using modified Rankin Scale (mRS) score at discharge and 3 months was no different among these subcohorts. A threshold of 16.99 mL of CIV, using the Youden index, resulted in a sensitivity of 90.5% and specificity of 58.1% for predicting mRS score of 0-2. A regression model identified gender, age, diabetes mellitus status, CIV, and smoking status as outcome determinants, which were used to develop the GADIS (Gender, Age, Diabetes Mellitus History, Infarct Volume, and Sex) scoring system to predict good clinical outcome. Using the GADIS score, <6 predicted mRS score 0-2 at discharge with a sensitivity of 83.3% and specificity of 80.6%. CONCLUSIONS: The GADIS score for patients with LVO-related acute ischemic stroke includes CIV after EMT and helps in early short-term prognostication. It is not intended to predict preintervention patient selection or outcome prediction.

Systemic response of coated-platelet and peripheral blood inflammatory cell indices after aneurysmal subarachnoid hemorrhage and long-term clinical outcome.

PURPOSE: Post-hemorrhage period after aneurysmal subarachnoid hemorrhage (aSAH) has several systemic manifestations including prothrombotic and pro-inflammatory states. Inter-relationship between these states using established/routine laboratory biomarkers and its long-term effect on clinical outcome is not well-defined. MATERIALS AND METHODS: Retrospective analysis of prospective cohort of 44 aSAH patients. Trend of procoagulant biomarkers [coated-platelets, mean platelet volume to platelet count (MPV:PLT)] and peripheral inflammatory biomarkers [platelet-lymphocyte ratio (PLR), neutrophil-platelet ratio (NLR)] were analyzed using regression analysis. Occurrence of delayed cerebral ischemia (DCI), modified Rankin score (mRS) of 3-6 and Montreal cognitive assessment (MoCA) of <26 at 1-year defined adverse clinical outcome. RESULTS: Patients with worse mRS and MoCA score had higher rise in coated-platelet compared to those with better scores [20.4 (IQR: 15.6, 32.9) vs. 10.95 (IQR: 6.1, 18.9), p = 0.003] and [16.9 (IQR: 13.4, 28.1) vs. 10.95 (IQR: 6.35, 18.65), p = 0.02] respectively. NLR and PLR trends showed significant initial decline followed by a gradual rise in NLR among those without DCI as compared to persistent low levels in those developing DCI (0.13 units/day vs. -0.07 units/day, p = 0.06). CONCLUSIONS: Coated-platelet rise after aSAH is associated with adverse long-term clinical outcome. NLR and PLR trends show an early immune-depressed state after aSAH.

Dasatinib Reinitiation After Poststroke Thrombolysis Associated with Symptomatic Intracerebral Hemorrhage.

BACKGROUND: Dasatinib, a tyrosine kinase inhibitor commonly used in treatment of acute lymphoblastic leukemia and chronic myelogenous leukemia, is often associated with hemorrhagic complications. Safety of dasatinib after thrombolytic therapy in acute ischemic stroke is unknown. CASE DESCRIPTION: A 63-year-old man with multiple vascular risk factors and chronic myelogenous leukemia (in molecular remission) on dasatinib presented with signs and symptoms of right hemispheric stroke owing to acute intracranial internal carotid artery occlusion that was treated with intravenous thrombolysis and mechanical thrombectomy resulting in near-complete resolution of stroke symptoms. The patient developed clinical worsening (>24 hours of thrombolytic therapy) after receiving a second dose of dasatinib that was due to symptomatic intracerebral hemorrhage and necessitated decompressive hemicraniectomy. Routine coagulation profile was normal. The etiology of this hemorrhagic complication was likely secondary to primary platelet dysfunction due to dasatinib as reported in some recent in vitro and ex vivo studies. CONCLUSIONS: It is advisable to withhold dasatinib during the poststroke period owing to its associated risk of symptomatic intracerebral hemorrhage.

Radiological Estimation of Intracranial Blood Volume and Occurrence of Hydrocephalus Determines Stress-Induced Hyperglycemia After Aneurysmal Subarachnoid Hemorrhage.

Acute phase after aneurysmal subarachnoid hemorrhage (aSAH) is associated with several metabolic derangements including stress-induced hyperglycemia (SIH). The present study is designed to identify objective radiological determinants for SIH to better understand its contributory role in clinical outcomes after aSAH. A computer-aided detection tool was used to segment admission computed tomography (CT) images of aSAH patients to estimate intracranial blood and cerebrospinal fluid volumes. Modified Graeb score (mGS) was used as a semi-quantitative measure to estimate degree of hydrocephalus. The relationship between glycemic gap (GG) determined SIH, mGS, and estimated intracranial blood and cerebrospinal fluid volumes were evaluated using linear regression. Ninety-four [94/187 (50.3%)] among the study cohort had SIH (defined as GG > 26.7 mg/dl). Patients with SIH had 14.3 ml/1000 ml more intracranial blood volume as compared to those without SIH [39.6 ml (95% confidence interval, CI, 33.6 to 45.5) vs. 25.3 ml (95% CI 20.6 to 29.9), p = 0.0002]. Linear regression analysis of mGS with GG showed each unit increase in mGS resulted in 1.2 mg/dl increase in GG [p = 0.002]. Patients with SIH had higher mGS [median 4.0, interquartile range, IQR 2.0-7.0] as compared to those without SIH [median 2.0, IQR 0.0-6.0], p = 0.002. Patients with third ventricular blood on admission CT scan were more likely to develop SIH [67/118 (56.8%) vs. 27/69 (39.1%), p = 0.023]. Hence, the present study, using unbiased SIH definition and objective CT scan parameters, reports "dose-dependent" radiological features resulting in SIH. Such findings allude to a brain injury-stress response-neuroendocrine axis in etiopathogenesis of SIH.

Trends of Platelet Volume Index Predicts Delayed Cerebral Ischemia After Subarachnoid Hemorrhage.

BACKGROUND: Delayed cerebral ischemia (DCI) is a major cause of disability after aneurysmal subarachnoid hemorrhage (aSAH). Activated platelets are surrogate markers for DCI occurrence and are reliably represented by mean platelet volume (MPV) to platelet count (PLT) ratio. If validated as a predictor of DCI, the ratio will allow clinicians to use it as a readily available tool in patient management. METHODS: Retrospective analysis of aSAH patient database at a tertiary care hospital. MPV:PLT ratio was defined as (MPV value(fL)PLT per 1000∗100). Nonlinear regression estimated differences in the ratio's pattern of change over time between those with or without DCI. Receiver operating characteristic curve determined optimal threshold of rise in MPV:PLT ratio to predict DCI. RESULTS: Average age of the cohort (n = 169) was 53.0 ± 13.0 years, and 38 patients (22.5%) developed DCI. Nonlinear regression analysis detected a transition of rising and declining MPV:PLT ratio at 3 days after aSAH. Rate of rise in MPV:PLT ratio was 0.5 units/day (95% confidence interval 0.3-0.7) in patients developing DCI as compared with 0.2 units/day (95% confidence interval 0.1-0.3) in those without DCI (P = 0.0004). Receiver operating characteristic analysis determined a threshold of 0.33 units/day rise in MPV:PLT predicted DCI with 89.5% sensitivity and 90.8% specificity. Patients who died demonstrated a steeper rise during the first 3 days (0.29 units/day) than those who were discharged home (0.21 units/day) (P = 0.004). CONCLUSIONS: Trend of MPV:PLT ratio after aSAH predicts DCI. This association alludes to significant early rise in reactive platelet population after aSAH in patients developing DCI.