Abstract WMP97: Regional Cerebral Oxygen Extraction is Elevated in Tissue at High Risk of Stroke in Pediatric Sickle Cell Disease

Stroke ◽  
2016 ◽  
Vol 47 (suppl_1) ◽  
Author(s):  
Andria L Ford ◽  
Kristin P Guilliams ◽  
Melanie Fields ◽  
Dustin K Ragan ◽  
Cihat Eldeniz ◽  
...  

Introduction: Children with sickle cell disease (SCD) are at high risk of stroke. Hemispheric oxygen extraction fraction (OEF) is a predictor of stroke in adults with carotid occlusion, but OEF has not been evaluated as a predictor of stroke in children with SCD. Hypothesis: OEF is elevated in SCD children compared to controls within a region at high risk of stroke as defined by an infarct heat-map created from a separate retrospective SCD cohort. Methods: A prospective MRI study enrolled 37 children aged 5-21: 17 with SCD and no stroke, 12 with SCD and silent infarcts (median infarct volume=0.3ml), and 8 sibling controls. None were on transfusions or had overt stroke history. Voxel-wise OEF was measured using an asymmetric spin echo sequence. In a separate retrospective cohort of 67 SCD children with overt and silent stroke, infarct regions on FLAIR were manually outlined and coregistered to an average T1 map to create an infarct heat-map (Fig A) which was used to define a “high risk” ROI (defined by >3% infarct density). This ROI was aligned to individual OEF maps from the prospective cohort (Fig B, average OEF map). OEF within the “high risk” ROI was compared between SCD children and controls; and between SCD children with and without infarction using Mann Whitney U tests. Results: The infarct heat-map from the retrospective cohort (Fig A) and the average OEF map from the prospective SCD cohort (Fig B) demonstrate striking co-localization of infarct density and elevated OEF. Within the “high risk” ROI, OEF was higher in SCD children compared to controls (39% [36, 46] vs. 23% [22, 27], p<0.0001 (Fig C). OEF within this “high risk” ROI did not differ between SCD children with and without infarcts (40% [38, 47] vs. 38% [35, 46], p=0.6). Conclusion: OEF in SCD children is elevated in the internal borderzone, a region with high stroke risk in SCD. Regional OEF may be a marker of cerebral metabolic stress that could be exploited to stratify stroke risk in this vulnerable population.

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 1387-1387
Author(s):  
Adam M Bush ◽  
Matthew Borzage ◽  
Soyoung Choi ◽  
Thomas Coates ◽  
John C Wood

Abstract Introduction Chronic Transfusion Therapy (CTT) has been successful in decreasing stroke frequency in patients with sickle cell disease (SCD). Despite this, indication for CTT is largely based on empirical evidence and the mechanisms by which CTT protects the brain remain unclear. CTT improves oxygen carrying capacity and lowers hemoglobin S%, but the corresponding impact on cerebral blood flow(CBF), cerebral metabolic rate (CMRO2), and oxygen extraction fraction (OEF) is unknown. Understanding the impact of these competing influences in non-transfused (NT) and chronically transfused (CT) SCD patients will inform stroke prevention. Thus, we measured CBF, CMRO2, and OEF, in NT and CT patients with SCD using magnetic resonance imaging (MRI). Methods All patients were recruited with informed consent or assent and this study was approved by the CHLA IRB. Fourteen (6 NT, 8 CT) patients with SCD and 12 healthy ethnicity matched controls (CTL) were studied. Exclusion criteria included pregnancy, previous stroke, acute chest or pain crisis hospitalization within one month. Complete blood count and hemoglobin electrophoresis were performed. Arterial oxygen saturation (SaO2) was measured via peripheral pulse oximetery. CaO2 was calculated as the product of hemoglobin, SaO2 and the oxygen density of hemoglobin (1.36 ml/g). Phase contrast imaging of the carotid and vertebral arteries was used to measure global CBF. T2 Relaxation Under Spin Tagging (TRUST) was used to measured T2 relaxation of blood within the sagittal sinus. T2 relaxation was converted to SvO2 via previously validated calibration curves. OEF represented the difference of SaO2 andSvO2 divided bySaO2. CMRO2 was calculated as the product of CBF and OEF. High resolution, 3D, T1 weighted images were used for brain volume calculation using BrainSuiteñ software. Results Table 1 summarizes the results. Hemoglobin and oxygen content were well matched between transfused and non transfused SCD patients. Cerebral metabolic rate was also nearly identical in the two groups. However, CT patients exhibited 25% higher CBF than NT SCD patients, allowing them to have a normal oxygen extraction fraction ~30%. In contrast, OEF in NT SCD patients was abnormally high (37.8%), suggesting a decreased extraction reserve. Total oxygenation index (TOI) by NIRS also trended lower in NT SCD patients, consistent with the greater oxygen extraction and lower cerebral venous saturations observed. Abstract 1387. TableCTL (reference)NTCTp value (NT vs CT)Hemoglobin (g/dl)13.5 ± 1.229.7 ± 1.259.7 ± 1.05nsCaO2 (umol O2/ml)9.85 ± .996.84 ± 1.176.95 ±.71nsCMRO2 (umol O2/100g/min)193.1 ± 44.9239.7 ± 35.3238.6 ± 38.3nsCBF (ml/100g/min)70.0 ± 12.8101.5 ± 16.6127.1 ± 23.5< 0.05OEF (%)30.0 ± 7.137.8. ± 3.0629.7 ± 7.53< 0.05NIRS TOI56.0 ± 4.0948.5 ± 4.2153.5 ± 8.760.076SvO2 (%)65.6 ± 6.856.2 ± 5.267.1 ± 6.7< 0.05 Discussion: Chronically transfused SCD patients achieve normal brain oxygenation metrics (SvO2, OEF, and NIRS) but require very high CBF to achieve this balance (lowering flow reserve). In contrast, NT SCD patients have smaller increases in CBF but require greater oxygen extraction to meet cerebrovascular demands (lowering extraction reserve). Hemoglobin S mediate changes in oxygen dissociation, blood viscosity, red cell deformability and microvascular damage potentially mediate these differences but their interplay is complicated and requires further study. Disclosures Coates: novartis: Consultancy, Honoraria, Speakers Bureau; shire: Consultancy, Honoraria; apo pharma: Consultancy, Honoraria; acceleron: Consultancy, Honoraria.


Neurology ◽  
2018 ◽  
Vol 90 (13) ◽  
pp. e1134-e1142 ◽  
Author(s):  
Melanie E. Fields ◽  
Kristin P. Guilliams ◽  
Dustin K. Ragan ◽  
Michael M. Binkley ◽  
Cihat Eldeniz ◽  
...  

ObjectiveTo determine mechanisms underlying regional vulnerability to infarction in sickle cell disease (SCD) by measuring voxel-wise cerebral blood flow (CBF), oxygen extraction fraction (OEF), and cerebral metabolic rate of oxygen utilization (CMRO2) in children with SCD.MethodsParticipants underwent brain MRIs to measure voxel-based CBF, OEF, and CMRO2. An infarct heat map was created from an independent pediatric SCD cohort with silent infarcts and compared to prospectively obtained OEF maps.ResultsFifty-six participants, 36 children with SCD and 20 controls, completed the study evaluation. Whole-brain CBF (99.2 vs 66.3 mL/100 g/min, p < 0.001), OEF (42.7% vs 28.8%, p < 0.001), and CMRO2 (3.7 vs 2.5 mL/100 g/min, p < 0.001) were higher in the SCD cohort compared to controls. A region of peak OEF was identified in the deep white matter in the SCD cohort, delineated by a ratio map of average SCD to control OEF voxels. CMRO2 in this region, which encompassed the CBF nadir, was low relative to all white matter (p < 0.001). Furthermore, this peak OEF region colocalized with regions of greatest infarct density derived from an independent SCD cohort.ConclusionsElevated OEF in the deep white matter identifies a signature of metabolically stressed brain tissue at increased stroke risk in pediatric patients with SCD. We propose that border zone physiology, exacerbated by chronic anemic hypoxia, explains the high risk in this region.


Author(s):  
Ji Y. Chong ◽  
Michael P. Lerario

Sickle cell disease may result in large vessel intracranial stenoses, which cause high rates of stroke. Screening for elevated velocities on transcranial Dopplers is a good way to stratify stroke risk. Patients at high stroke risk should participate in an exchange transfusion program indefinitely to reduce the rate of subsequent stroke. Although there is a high risk of stroke in pediatric sickle cell patients, the use of IV tPA in this population is largely unstudied and not routinely recommended due to unclear safety and efficacy.


PEDIATRICS ◽  
2016 ◽  
Vol 137 (Supplement 3) ◽  
pp. 264A-264A
Author(s):  
Parth J. Bhatt ◽  
Dinesh Singh ◽  
Akingbola Olubenga ◽  
Devraj Chavda ◽  
Achint Patel

2021 ◽  
pp. 1-4
Author(s):  
Mohammad Ali ◽  
Lina Okar ◽  
Nabil E. Omar ◽  
Jabeed Parengal ◽  
Ashraf Soliman ◽  
...  

Despite the widespread of coronavirus disease-19 (CO­VID-19) infection around the world, there are very scarce reported literature about the care of patients with a known diagnosis of hemoglobin disorders such as sickle cell disease (SCD) or thalassemia and confirmed COVID-19 infection. Thalassemia International Federation issued a position statement to include patients with thalassemia and SCD among the high-risk groups of patients. Here, we present an interesting case of a 42-year-old patient know to have SCD presenting with Vaso-occlusive (VOC) pain episode in the absence of COVID-19 signs and symptoms, who tested positive for COVID-19 infection and had a smooth recovery. This case highlights the importance of screening SCD patients presenting with VOC-related events even in the absence of COVID-19 signs and symptoms.


Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 68-68 ◽  
Author(s):  
Janet L. Kwiatkowski ◽  
Julie Kanter ◽  
Heather J. Fullerton ◽  
Jenifer Voeks ◽  
Ellen Debenham ◽  
...  

Abstract Background: The Stroke Prevention Trial in Sickle Cell Anemia (STOP) and Optimizing Primary Stroke Prevention in Sickle Cell Anemia (STOP 2) established routine transcranial Doppler ultrasound (TCD) screening with indefinite chronic red cell transfusions (CRCT) for children with abnormal TCD as standard of care. To identify children at high-risk of stroke, annual TCD screening is recommended from ages 2 to 16 years, with more frequent monitoring if the result is not normal. A reduction in stroke incidence in children with SCD has been reported in several clinical series and analyses utilizing large hospital databases when comparing rates before and after the publication of the STOP study in 1998. We sought to determine the rate of first ischemic stroke in a multicenter cohort of children who had previously participated in the STOP and/or STOP 2 trials and to determine whether these strokes were screening or treatment failures. Subjects and Methods: Between 1995 and 2005, STOP and STOP 2 (STOP/2) were conducted at 26 sites in the US and Canada. These studies included 3,835 children, ages 2 to 16 y with SCD type SS or S-beta-0-thalassemia. Participation in STOP/2 ranged from a single screening TCD to randomization. STOP 2 also had an observational arm for children on CRCT for abnormal TCD whose TCD had not reverted to normal. The Post-STOP study was designed to follow-up the outcomes of children who participated in one or both trials. 19 of the 26 original study sites participated in Post-STOP, contributing a total of 3,539 (92%) of the STOP/2 subjects. After exit from STOP/2, these children received TCD screening and treatment according to local practices. Data abstractors visited each clinical site and obtained retrospective data from STOP/2 study exit to 2012-2014 (depending on site) including follow-up TCD and brain imaging results, clinical information, and laboratory results. Two vascular neurologists, blinded to STOP/2 status and prior TCD and neuroimaging results, reviewed source records to confirm all ischemic strokes, defined as a symptomatic cerebral infarction; discordant opinions were resolved through discussion. For the first Post-STOP ischemic stroke, prior TCD result and treatment history subsequently were analyzed. Results: Of the 3,539 subjects, follow-up data were available for 2,850 (81%). Twelve children who had a stroke during STOP or STOP2 were excluded from these analyses resulting in data on 2,838 subjects. The mean age at the start of Post-STOP was 10.5 y and mean duration of follow-up after exiting STOP/2 was 9.1 y. A total of 69 first ischemic strokes occurred in the Post-STOP observation period (incidence 0.27 per 100 pt years). The mean age at time of stroke was 14.4±6.2 (median 13.8, range 3.5-28.9) y. Twenty-five of the 69 patients (36%) had documented abnormal TCD (STOP/2 or Post-STOP) prior to the stroke; 15 (60%) were receiving CRCT and 9 (36%) were not (treatment data not available for 1 subject). Among the 44 subjects without documented abnormal TCD, 29 (66%) had not had TCD re-screen in the Post-STOP period prior to the event; 7 of these 29 (24%) were 16 y or older at the start of Post-STOP, which is beyond the recommended screening age. Four of the 44 (9%) patients had inadequate TCD in Post-STOP (1 to 10.7 y prior to event). Six (14%) had normal TCD more than a year before the event (1.2 - 4 y); all but one of these children were younger than 16 y at the time of that TCD. Only 5 (11%) had a documented normal TCD less than 1 year prior to the event. Conclusions: In the Post-STOP era, the rate of first ischemic stroke was substantially lower than that reported in the Cooperative Study of Sickle Cell Disease, prior to implementation of TCD screening. Many (39%) of the Post-STOP ischemic strokes were associated with a failure to re-screen according to current guidelines, while only 11% occurred in children who had had recent low-risk TCD. Among those known to be at high risk prior to stroke, treatment refusal or inadequate treatment may have contributed. While TCD screening and treatment are effective at reducing ischemic stroke in clinical practice, significant gaps in screening and treatment, even at sites experienced in the STOP protocol, remain to be addressed. Closing these gaps should provide yet further reduction of ischemic stroke in SCD. Disclosures No relevant conflicts of interest to declare.


2020 ◽  
Vol 13 (2) ◽  
pp. 186-192 ◽  
Author(s):  
Narcisse Elenga ◽  
Donald Celicourt ◽  
Blandine Muanza ◽  
Gisèle Elana ◽  
Sévérine Hocquelet ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document