Early Reperfusion Research Articles

Thrombus extraction in acute ischemic stroke: three years of experience at the regional vascular center

From a modern perspective, the key to successful treatment of ischemic stroke is early reperfusion with systemic thrombolytic therapy and thrombus extraction. Thrombectomy is the only reliable method of recanalization in patients with thrombosis of a large cerebral artery. Despite the fact that thrombus extraction has proven its effectiveness in the treatment of acute ischemic stroke in a number of large randomized trials, there are still issues that have not been fully studied, on which there are controversial opinions among specialists. For instance, there is different information about whether direct thrombectomy or thrombus extraction after systemic thrombolysis is more effective and safer. Moreover, in accordance with modern procedures for providing care to patients with acute cerebral circulatory disorders, patients admitted in the «therapeutic window» should receive intravenous thrombolytic therapy even if thrombectomy is planned. Based on the analysis of 164 thrombus extractions in patients with acute ischemic stroke admitted to the regional vascular center in 2020–2023, the results of direct thrombus extraction and staged reperfusion (systemic thrombolytic therapy + thrombectomy) were compared. It has been found that compared to direct thrombus extraction, staged reperfusion provides more frequent achievement of 2b-3 recanalization (71.83 % and 78.49 %, respectively), accompanied by lower mortality (45 % and 23.66 %, respectively) and more frequent achievement of Rankin 0–2 functional status at the time of discharge (48.72 % and 61.96 %, respectively). The worst results were observed among patients with vascular occlusion in the vertebrobasilar basin, at TICI 0-2a and the age of patients over 80 years.

Transcriptional Profiling Underscores the Role of Preprocurement Allograft Metabolism and Innate Immune Status on Outcomes in Human Liver Transplantation.

The adverse effects of ischemia-reperfusion injury (IRI) remain a principal barrier to a successful outcome after lifesaving orthotopic liver transplantation (OLT). Gene expression during different phases of IRI is dynamic and modified by individual exposures, making it attractive for identifying potential therapeutic targets for improving the number of suitable organs for transplantation and patient outcomes. However, data remain limited on the functional landscape of gene expression during liver graft IRI, spanning procurement to reperfusion and recovery. Therefore, we sought to characterize transcriptomic profiles of IRI during multiple phases in human OLT. We conducted clinical data analyses, histologic evaluation, and RNA sequencing of 17 consecutive human primary OLT. We performed liver allograft biopsies at 4 time points: baseline (B, before donor cross-clamp), at the end of cold ischemia (CI), during early reperfusion (ER, after revascularization), and during late reperfusion (LR). Data were generated and then recipients grouped by post-OLT outcomes categories: immediate allograft function (IAF; n = 11) versus early allograft dysfunction (EAD; n = 6) groups. We observed that CI (vs B) modified a transcriptomic landscape enriched for a metabolic and immune process. Expression levels of hallmark inflammatory response genes were higher transitioning from CI to ER and decreased from ER to LR. IAF group predominantly showed higher bile and fatty acid metabolism activity during LR compared with EAD group, while EAD group maintained more immunomodulatory activities. Throughout all time points, EAD specimens exhibited decreased metabolic activity in both bile and fatty acid pathways. We report transcriptomic profiles of human liver allograft IRI from prepreservation in the donor to posttransplantation in the recipient. Immunomodulatory and metabolic landscapes across ER and LR phases were different between IAF and EAD allografts. Our study also highlights marker genes for these biological processes that we plan to explore as novel therapeutic targets or surrogate markers for severe allograft injury in clinical OLT.

A Membrane-Targeting Aggregation-Induced Emission Probe for Monitoring Lipid Droplet Dynamics in Ischemia/Reperfusion-Induced Cardiomyocyte Ferroptosis.

Myocardial ischemia/reperfusion injury (MIRI) is the leading cause of irreversible myocardial damage. A pivotal pathogenic factor is ischemia/reperfusion (I/R)-induced cardiomyocyte ferroptosis, marked by iron overload and lipid peroxidation. However, the impact of lipid droplet (LD) changes on I/R-induced cardiomyocyte ferroptosis is unclear. In this study, an aggregation-induced emission probe, TPABTBP is developed that is used for imaging dynamic changes in LD during myocardial I/R-induced ferroptosis. TPABTBP exhibits excellent LD-specificity, superior capability for monitoring lipophagy, and remarkable photostability. Molecular dynamics (MD) simulation and super-resolution fluorescence imaging demonstrate that the TPABTBP is specifically localized to the phospholipid monolayer membrane of LDs. Imaging LDs in cardiomyocytes and myocardial tissue in model mice with MIRI reveals that the LD accumulation level increase in the early reperfusion stage (0-9h) but decrease in the late reperfusion stage (>24h) via lipophagy. The inhibition of LD breakdown significantly reduces the lipid peroxidation level in cardiomyocytes. Furthermore, it is demonstrated that chloroquine (CQ), an FDA-approved autophagy modulator, can inhibit ferroptosis, thereby attenuating MIRI in mice. This study describes the dynamic changes in LD during myocardial ischemia injury and suggests a potential therapeutic target for early MIRI intervention.

Hypothermic Oxygenated Perfusion Improves Vascular and Contractile Function by Preserving Endothelial Nitric Oxide Production in Cardiac Grafts Obtained With Donation After Circulatory Death.

Cardiac donation after circulatory death is a promising option to increase graft availability. Graft preservation with 30 minutes of hypothermic oxygenated perfusion (HOPE) before normothermic machine perfusion may improve cardiac recovery as compared with cold static storage, the current clinical standard. We investigated the role of preserved nitric oxide synthase activity during HOPE on its beneficial effects. Using a rat model of donation after circulatory death, hearts underwent insitu ischemia (21 minutes), were explanted for a cold storage period (30 minutes), and then reperfused under normothermic conditions (60 minutes) with left ventricular loading. Three cold storage conditions were compared: cold static storage, HOPE, and HOPE with Nω-nitro-L-arginine methyl ester (nitric oxide synthase inhibitor). To evaluate potential confounding effects of high coronary flow during early reperfusion in HOPE hearts, bradykinin was administered to normalize coronary flow to HOPE levels in 2 additional groups (cold static storage and HOPE with Nω-nitro-L-arginine methyl ester). Cardiac recovery was significantly improved in HOPE versus cold static storage hearts, as determined by cardiac output, left ventricular work, contraction and relaxation rates, and coronary flow (P<0.05). Furthermore, HOPE attenuated postreperfusion calcium overload. Strikingly, the addition of Nω-nitro-L-arginine methyl ester during HOPE largely abolished its beneficial effects, even when early reperfusion coronary flow was normalized to HOPE levels. HOPE provides superior preservation of ventricular and vascular function compared with the current clinical standard. Importantly, HOPE's beneficial effects require preservation of nitric oxide synthase activity during the cold storage. Therefore, the application of HOPE before normothermic machine perfusion is a promising approach to optimize graft recovery in donation after circulatory death cardiac grafts.

Development of a Large Animal Model of Ischemia-free Liver Transplantation in Pigs.

In organ transplantation, ischemia, and reperfusion injury (IRI) is considered as an inevitable event and the major contributor to graft failure. Ischemia-free liver transplantation (IFLT) is a novel transplant procedure that can prevent IRI and provide better transplant outcomes. However, a large animal model of IFLT has not been reported. Therefore, we develop a new, reproducible, and stable model of IFLT in pigs for investigating mechanisms of IFLT in IRI. Ten pigs were subjected to IFLT or conventional liver transplantation (CLT). Donor livers in IFLT underwent 6-h continuous normothermic machine perfusion (NMP) throughout graft procurement, preservation, and implantation, whereas livers in CLT were subjected to 6-h cold storage before implantation. The early reperfusion injury was compared between the 2 groups. Continuous bile production, low lactate, and liver enzyme levels were observed during NMP in IFLT. All animals survived after liver transplantation. The posttransplant graft function was improved with IFLT when compared with CLT. Minimal histologic changes, fewer apoptotic hepatocytes, less sinusoidal endothelial cell injury, and proinflammatory cytokine (interleukin [IL]-1β, IL-6, and tumor necrosis factor-α) release after graft revascularization were documented in the IFLT group versus the CLT group. We report that the concept of IFLT is achievable in pigs. This innovation provides a potential strategy to investigate the mechanisms of IRI and provide better transplant outcomes for clinical practice.

Complications in Emergency Department Patients with Acute Coronary Syndrome with Contemporary Care

Introduction: With the implementation of early reperfusion therapy, the number of complications in patients with acute coronary syndrome (ACS) has diminished significantly. However, ACS patients are still routinely admitted to units with high-level monitoring such as the coronary or intensive care unit (CCU/ICU). The cost of these admissions is high and there is often a shortage of beds. The aim of this study was to analyze the complications in contemporary emergency department (ED) patients with ACS and to map patient management. Methods: This observational study was a secondary analysis of data collected in the ESC-TROP trial (NCT03421873) that included 26,545 consecutive chest pain patients ≥18 years at five Swedish EDs. Complications were defined as the following within 30 days: death, cardiac arrest, cardiogenic shock, pulmonary edema, severe ventricular arrhythmia, high-degree atrioventricular (AV) block that required a pacemaker, and mechanical complications such as papillary muscle rupture, cardiac tamponade, or ventricular septum defects (VSDs). Complications were identified via diagnosis and/or intervention codes in the database, and manual chart review was performed in cases with complications. Results: Of all 26,545 patients, 2,463 (9.3%) were diagnosed with ACS, and 151 of these (6.1%) suffered any complication within 30 days. Mean age was higher in patients with (79.2 years) than without (69.4 years) complications, and more were female (39.7% vs. 33.0%). Eighty-four (3.4% of all ACS patients) patients died, 33 (1.3%) had cardiac arrest, 22 (0.9%) respiratory failure, 13 (0.5%) high-degree AV block, 10 (0.4%) cardiogenic shock, 12 (0.5%) severe ventricular arrhythmia, and 2 each (<0.1%) had VSD or cardiac tamponade. Almost 30% of the complications were present already at the ED, and 40% of patients with complications were not admitted to the CCU/ICU. Only 80 (53%) of the patients with complications underwent coronary angiography and 62 (41%) were revascularized with percutaneous coronary intervention or coronary artery bypass grafting. Conclusion: With current care, serious complications occurred in only 6 out of 100 ACS patients, and 2 of these complications were present already at the ED. Four out of 10 ACS patients with complications were not admitted to the CCU/ICU and about half did not undergo coronary angiography. Further research is needed to improve risk assessment in ED ACS patients, which may allow more effective use of cardiac monitoring and hospital resources.

Molecular Mechanisms of Ischemic Stroke: A Review Integrating Clinical Imaging and Therapeutic Perspectives.

Ischemic stroke poses a significant global health challenge, necessitating ongoing exploration of its pathophysiology and treatment strategies. This comprehensive review integrates various aspects of ischemic stroke research, emphasizing crucial mechanisms, therapeutic approaches, and the role of clinical imaging in disease management. It discusses the multifaceted role of Netrin-1, highlighting its potential in promoting neurovascular repair and mitigating post-stroke neurological decline. It also examines the impact of blood-brain barrier permeability on stroke outcomes and explores alternative therapeutic targets such as statins and sphingosine-1-phosphate signaling. Neurocardiology investigations underscore the contribution of cardiac factors to post-stroke mortality, emphasizing the importance of understanding the brain-heart axis for targeted interventions. Additionally, the review advocates for early reperfusion and neuroprotective agents to counter-time-dependent excitotoxicity and inflammation, aiming to preserve tissue viability. Advanced imaging techniques, including DWI, PI, and MR angiography, are discussed for their role in evaluating ischemic penumbra evolution and guiding therapeutic decisions. By integrating molecular insights with imaging modalities, this interdisciplinary approach enhances our understanding of ischemic stroke and offers promising avenues for future research and clinical interventions to improve patient outcomes.

Incidence and predictors of heart failure with reduced and preserved ejection fraction after ST-elevation myocardial infarction in the contemporary era of early percutaneous coronary intervention.

The development and incidence of de-novo heart failure after ST-elevation myocardial infarction (STEMI) in the contemporary era of rapid reperfusion are largely unknown. We aimed to establish the incidence of post-STEMI heart failure, stratified by left ventricular ejection fraction (LVEF) and to find predictors for its occurrence. Furthermore, we investigated the course of left ventricular systolic and diastolic function after STEMI. A total of 1172 all-comer STEMI patients from the CardioLines Biobank were included. Patients were predominantly male (74.5%) and 64 ± 12 years of age. During a median follow-up of 3.7 years (2.0, 5.5) we found a total incidence of post-STEMI heart failure of 10.9%, of which 52.1% heart failure with reduced ejection fraction (HFrEF), 29.4% heart failure with mildly reduced ejection fraction and 18.5% heart failure with preserved ejection fraction (HFpEF). Independent predictors for the development of HFrEF were male sex (β = 0.97, p = 0.009), lung crepitations (β = 1.09, p = 0.001), potassium level (mmol/L, β = 0.43, p = 0.012), neutrophil count (109/L, β = 0.09, p = 0.001) and a reduced LVEF (β = 1.91, p < 0.001) at baseline. Independent predictors for the development of HFpEF were female sex (β = 0.99, p = 0.029), pre-existing kidney failure (β = 1.95, p = 0.003) and greater left atrial volume index (β = 0.04, p = 0.033) at baseline. Follow-up echocardiography (median follow-up 20 months) showed an improvement in LVEF (p < 0.001), whereas changes in diastolic function parameters showed both improvement and deterioration. In the current era of early STEMI reperfusion, still one in 10 patients develops heart failure, with approximately half of the patients with a reduced and half with a mildly reduced or normal LVEF. Predictors for the development of HFrEF were different from HFpEF.

Baicalin attenuates neuronal damage associated with SDH activation and PDK2-PDH axis dysfunction in early reperfusion

BackgroundEnergy deficiency and oxidative stress are interconnected during ischemia/reperfusion (I/R) and serve as potential targets for the treatment of cerebral ischemic stroke. Baicalin is a neuroprotective antioxidant, but the underlying mechanisms are not fully revealed. PurposeThis study explored whether and how baicalin rescued neurons against ischemia/reperfusion (I/R) attack by focusing on the regulation of neuronal pyruvate dehydrogenase kinase 2 (PDK2)-pyruvate dehydrogenase (PDH) axis implicated with succinate dehydrogenase (SDH)-mediated oxidative stress. Study designThe effect of the tested drug was explored in vitro and in vivo with the model of oxygen-glucose deprivation/reoxygenation (OGD/R) and middle cerebral artery occlusion/reperfusion (MCAO/R), respectively. MethodsNeuronal damage was evaluated according to cell viability, infarct area, and Nissl staining. Protein levels were measured by western blotting and immunofluorescence. Gene expression was investigated by RT-qPCR. Mitochondrial status was also estimated by fluorescence probe labeling. ResultsSDH activation-induced excessive production of reactive oxygen species (ROS) changed the protein expression of Lon protease 1 (LonP1) and hypoxia-inducible factor-1ɑ (HIF-1ɑ) in the early stage of I/R, leading to an upregulation of PDK2 and a decrease in PDH activity in neurons and cerebral cortices. Treatment with baicalin prevented these alterations and ameliorated neuronal ATP production and survival. ConclusionBaicalin improves the function of the neuronal PDK2-PDH axis via suppression of SDH-mediated oxidative stress, revealing a new signaling pathway as a promising target under I/R conditions and the potential role of baicalin in the treatment of acute ischemic stroke.

Second Edition of the German–Austrian S3 Guideline “Infarction-Related Cardiogenic Shock: Diagnosis, Monitoring and Treatment”

The mortality of patients with MI has significantly decreased in recent decades, mainly due to early reperfusion therapy with a probability of surviving of more than 90% if the patient reaches the hospital [...]

Histone deacetylase inhibition by suberoylanilide hydroxamic acid during reperfusion promotes multifaceted brain and vascular protection in spontaneously hypertensive rats with transient ischaemic stroke

Hypertension is the most prevalent modifiable risk factor for stroke and is associated with worse functional outcomes. Pharmacological inhibition of histone deacetylases by suberoylanilide hydroxamic acid (SAHA) modulates gene expression and has emerged as a promising therapeutic approach to reduce ischaemic brain injury. Here, we have tested the therapeutic potential of SAHA administered during reperfusion in adult male spontaneously hypertensive (SHR) rats subjected to transient middle cerebral artery occlusion (tMCAO; 90 min occlusion/24 h reperfusion). Animals received a single dose of SAHA (50 mg/kg) or vehicle i.p. at 1, 4, or 6 h after reperfusion onset. The time-course of brain histone H3 acetylation was studied. After tMCAO, drug brain penetrance and beneficial effects on behavioural outcomes, infarct volume, oedema, angiogenesis, blood-brain barrier integrity, cerebral artery oxidative stress and remodelling, and brain and vascular inflammation were evaluated. SAHA increased brain histone H3 acetylation from 1 to 6 h after injection, reaching the ischaemic brain administered during reperfusion. Treatment given at 4 h after reperfusion onset improved neurological score, reduced infarct volume and oedema, attenuated microglial activation, prevented exacerbated MCA angiogenic sprouting and blood-brain barrier breakdown, normalised MCA oxidative stress and remodelling, and modulated brain and cerebrovascular cytokine expression. Overall, we demonstrate that SAHA administered during early reperfusion exerts robust brain and vascular protection after tMCAO in hypertensive rats. These findings are aligned with previous research in ischaemic normotensive mice and help pave the way to optimise the design of clinical trials assessing the effectiveness and safety of SAHA in ischaemic stroke.

Abstract WP74: Organized System of Care Improves Door to Needle Times in Rural Montana

Early reperfusion is critical to improved outcomes from acute stroke, with door-to-CT times &lt; 25 min and door-to-needle times &lt; 60 min as key performance metrics. These may be difficult to achieve in critical access hospitals (CAHs) due to low volumes, longer EMS transport, delays to provider response, challenges in obtaining rapid CT, and lack of access to neurology consultation. Each of these represent appropriate targets for performance improvement efforts. Methods: In 2022, The Montana Stroke Initiative began a quality improvement project to improve door-to-CT and door-to-needle times for acute stroke in rural Montana (MT) with the following objectives: 1. Engage more CAHs in the stroke registry. 2. Initiate monthly clinical learning collaboratives to share stroke data and best practices in reducing door-to-CT times. 3. Create statewide stroke order-sets. 4. Involve stroke coordinators and physicians from MT’s certified stroke centers in providing education on the order-sets, NIHSS, and the importance of data abstraction for quality improvement. The Montana Department of Health and Human Services collects statewide stroke data using the Get With The Guidelines®-Stroke registry. For this analysis, all CAH acute stroke patients evaluated for thrombolytic therapy in 2021 and 2022-23 were included. These cohorts were compared to total number of patients and the primary outcome measures of door-to-CT time &lt;25 min and door-to-needle time &lt; 60 min. Registry participation doubled from 12 hospitals in 2021 to 24 in 2022-23. The total number of suspected stroke patients increased from 126 patients in 2021 to 269 patients in 2022-23. Mean Door-to-CT time decreased from 56 min to 39 min (p=0.004), with Door-to-CT times 25 min increasing from 31.7% to 50.6% (p&lt;0.001). Thrombolytic therapy was given to a total of 10 patients in 2021 and 36 patients in 2022-23. Mean Door-to-Needle time decreased from 118 min to 77 min (p=0.026), with Door-to-Needle times 60 min increasing from 10.0% to 33.3% (p=0.24).In conclusion, an organized effort to improve door-to-CT processes for suspected stroke patients, including sharing data and best practices, and providing focused education, has resulted in more patients receiving lytic therapy in the recommended time of &lt; 60 minutes.

Abstract WP40: Enhanced Team Communication Improves Door to Device Times

Background: Patients experiencing acute ischemic stroke benefit from early reperfusion. The American Heart Association set a goal for hospitals performing mechanical thrombectomy to achieve ‘door to device’ (DTD) time of less than 90 minutes for 50% of eligible patients. In 2021, only 23% of patients were meeting this time target. These patients require complex care and timely communication between various practitioners. It was noted that these practitioners were working in silos, which resulted in unnecessary delays. The need for enhanced communication was identified as an intervention to improve performance. Methods: Key team members are equipped with a dedicated phone using an artificial intelligence application, which provides an early signal when large vessel occlusion is detected. This allows for earlier mobilization of resources. This is particularly important for emergency department and interventional radiology nurses who are the ones driving transition of care between departments. In addition, the anesthesia department uses closed loop communication to notify the team of their readiness to receive the patient. Lastly, timely debriefs for all practitioners involved in the case provide a forum for constructive, thoughtful feedback about ways to be more efficient. Results: After enhanced communication strategies were implemented in quarter 2 of 2022, DTD times improved to 43% in quarter 3 of 2022, 50% in quarter 4 of 2022, 67% in quarter 1 of 2023 and 75% in quarter 2 of 2023. Conclusions: Providing tools to enhance communication amongst various practitioners has resulted in sustained improvement in DTD times. Future data collection should focus on associating these improved DTD times with long term functional outcomes.

Abstract TP140: Effect of MR-Guided Perfusion Imaging Mismatch Profiles Within 6 Hours on Endovascular Thrombectomy Outcomes

Background: The treatment of acute ischemic stroke (AIS) aims to achieve early vascular recanalization and reperfusion of the penumbra. However, the effect of early penumbral imaging within 6 hours on clinical outcomes remains unclear. Objective: The objective of this study was to determine the effect of magnetic resonance-guided (MR-guided) perfusion imaging within 6 hours after symptom onset on endovascular thrombectomy outcomes in AIS patients. Methods: We prospectively collected the clinical information of consecutive AIS patients undergoing endovascular thrombectomy based on MR-guided perfusion imaging within 6 hours after symptom onset from AISRNA and EVTRNA studies. The primary outcome was defined as the poor outcome (mRS &gt; 2 within 90 days). The perfusion-weighted imaging/diffusion-weighted imaging (PWI/DWI) mismatch was assessed by an automated software. Results: We enrolled 84 patients (25 in the mismatch ≤ 1.8 group and 59 in the mismatch &gt; 1.8 group). Significant difference was found between the mismatch&gt;1.8 group and the mismatch≤1.8 group for the incidence of disabling stroke (mRS &gt; 2) within 90 days (40.7% vs. 68.0%, OR: 3.099, 95% CI: 1.154-8.323, P =0.025). Intracranial hemorrhage occurred in 8 patients (13.6%) in the mismatch &gt; 1.8 group and 10 patients in the mismatch ≤ 1.8 group (40.0%) (P = 0.010). The risk of severe cerebral edema was 2/59 (3.4%) vs. 7/25 (28.0%) (P = 0.004). These findings remained stable after adjustment. Conclusion: MR-guided perfusion imaging mismatch profiles within 6 hours after symptom onset may be feasible to improve clinical outcomes and reduce clinically ineffective reperfusion after endovascular thrombectomy.

Abstract WMP30: Real World Experience With Tenecteplase on a Mobile Stroke Unit

Background: Tenecteplase (TNK) administered on a mobile stroke unit (MSU) has demonstrated superior rates of early reperfusion compared to alteplase. Current guidelines include TNK as a second-tier option for large vessel occlusions as TNK has many benefits, including rapid IV administration and ease of dosing. The objective of this study was to describe real world utilization of TNK on a MSU. Methods: This was a retrospective observational study of patients receiving TNK as compared to alteplase between February 2021 and April 2023 at a large academic comprehensive stroke center. Baseline demographics, GCS, NIHSS, as well as time of initial imaging were collected. Primary endpoint was time from MSU door to thrombolytic administration. Secondary endpoints included: MSU door to imaging interpretation, dispatch to thrombolytic administration, and provider decision time to thrombolytic administration. Safety endpoints included symptomatic ICH within 24 hours. Results: During the studied time period 40 patients received alteplase and 32 patients received TNK on the MSU. The median age was 65.7 years and median NIHSS score was 9. There was no difference in time from MSU door to thrombolytic administration (15 vs 17.5, p=0.30). There was also no difference in time from MSU door to imaging interpretation, dispatch to thrombolytic administration, or provider decision time to thrombolytic administration. No hemorrhagic conversion occurred. Conclusion: This is the largest series to date describing real-world utilization of TNK administration in a MSU. There were no significant differences in time to therapy in any of the time points evaluated. This data is promising for the treatment of ischemic stroke in which time to administration of thrombolytic therapy is paramount and TNK is administered as a rapid IV injection as compared to alteplase infusion.

Abstract WMP36: Quality Improvement for Improved Ischemic Stroke Large Vessel Occlusion Door-In-Door-Out Times at an Urban Primary Stroke Center Integrated Health System

Background: Stroke patients who present to an Emergency Department (ED) with an acute ischemic stroke (AIS) due to a large vessel occlusion (LVO) and are eligible for endovascular stroke therapy (EST) require rapid transfer to a facility capable of EST. Nationwide data for 2022 suggest that 19% of LVO patients are transferred for EST within 90 minutes. Our practice center is a large urban community-based Primary Stroke Center, part of a spoke and hub integrated system. In 2022, we had a median door-in-door-out (DIDO) time of 98 min with 33% percent of cases under 90 min (n = 12). Purpose: Knowing the importance of early reperfusion, we implemented a quality improvement project using a pre-post design to improve our DIDO times for patients with AIS due to LVO, with a goal of achieving a median DIDO time of 75 min or less. Methods: Our approach was multidisciplinary. We completed comprehensive chart reviews focusing on critical time points and reviewed recent literature (2022 - 2023) for best practices. We created an ED interdisciplinary DIDO workgroup which developed and implemented a DIDO checklist after education and socialization. In March 2023, we created a dedicated regional neuro transfer hub to address changes with EMS notification and response to expedite LVO transfers. Other DIDO literature recommendations were already in place, including the use of a regionalized telestroke program. Best practices identified but not implemented focused on Emergency Medical Services (EMS), such as holding a rig while completing imaging, providing enroute reports, and conducting joint drills post-COVID. Results: After the implementation of the DIDO checklist, DIDO times decreased to 82 minutes from August 2022 to July 2023 (a decrease of 16 min), with 44% of cases under 75 mins (n = 9). Our median time for 2023 (January - July) is 68 min (n = 2). Conclusion: Transfer of LVO patients is a low-volume, high-risk event, but one where every minute matters for optimal patient outcomes. The DIDO checklist was a helpful aid for staff to ensure key steps were completed timely, leading to a decrease in DIDO times.

Abstract TP305: microRNA-182 Preserves Oxidative Phosphorylation During Substrate Limitation in Both Male and Female Primary Astrocyte Cultures

Introduction: Stroke remains the leading cause of long-term disability in the United States, with therapy remaining limited to early reperfusion interventions. Adjuvants that aim to preserve neuronal survival could provide functional benefits to stroke survivors. Astrocytes promote neuronal survival by providing metabolic support to neurons in the absence of glucose availability, a critical substrate required for neuronal metabolism and survival. MicroRNAs (miRs) are non-coding RNAs that suppress translation of target genes. Our prior work identified miR-182 as a critical modulator of stroke by targeting genes that preserve astrocyte mitochondrial function. In the present study we assessed the role of miR-182 inhibition on oxygen consumption rate (OCR) during glucose deprivation (GD) injury. As stroke-induced mitochondrial dysfunction occurs mechanistically differently between males and females, we compared the effect of miR-182 inhibition between male and female astrocytes. Methods: Primary male and female cortical astrocyte cultures were generated from neonatal male and female C57BL/6 mice. Cultures were maintained at ambient O 2 tension and 5% CO 2 until day-in-vitro 12. Cultures were randomized to transfection with miR-182 inhibitor, or mismatch control RNA, 24h prior to 72h of GD injury. OCR was measured using the Lucid Scientific Recipher TM . Cell plating density was assessed using the nuclear stain DAPI. Results: No significant differences between treatments or between sexes in cell density were observed. GD injury resulted in a progressive decrease in OCR, requiring 12.5+7.8h to become significantly (p&lt;0.05) lower in male astrocyte cultures, and 12.5+6.4h in females, with no difference between sexes. Comparatively, time-to-reach a lower OCR with miR-182 inhibitor required 38+7.1h in male cultures and 47+12.7h in females. The time-to-reach a lower OCR with miR-182 inhibition was significantly greater in both sexes versus control transfection, but not between sexes with miR-182 inhibition. Conclusions: These results suggest that inhibition of miR-182 represents a novel target to indirectly support neuronal metabolism during stroke that could be applied to both men and women survivors of stroke to improve functional outcomes.

Hydrocortisone cardioprotection in ischaemia/reperfusion injury involves antioxidant mechanisms.

Glucocorticoid (GR) and mineralocorticoid (MR) receptors are highly expressed in cardiac tissue, and both can be activated by corticosteroids. MR activation, in acute myocardial infarction (AMI), worsens cardiac function, and increase NHE activity contributing to the deleterious process. In contrast, effects of GR activation are not fully understood, probably because of the controversial scenario generated by using different doses or potencies of corticosteroids. We tested the hypothesis that an acute dose of hydrocortisone (HC), a low-potency glucocorticoid, in a murine model of AMI could be cardioprotective by regulating NHE1 activity, leading to a decrease in oxidative stress. Isolated hearts from Wistar rats were subjected to regional ischemic protocol. HC (10 nmol/L) was added to the perfusate during early reperfusion. Infarct size and oxidative stress were determined. Isolated papillary muscles from non-infarcted hearts were used to evaluate HC effect on sodium-proton exchanger 1 (NHE1) by analysing intracellular pH recovery from acute transient acidosis. HC treatment decreased infarct size, improved cardiac mechanics, reduced oxidative stress after AMI, while restoring the decreased level of the pro-fusion mitochondrial protein MFN-2. Co-treatment with the GR-blocker Mifepristone avoided these effects. HC reduced NHE1 activity by increasing the NHE1 pro-inhibiting Ser648 phosphorylation site and its upstream kinase AKT. HC restored the decreased AKT phosphorylation and anti-apoptotic BCL-2 protein expression detected after AMI. Our results provide the first evidence that acute HC treatment during early reperfusion induces cardioprotection against AMI, associated with a non-genomic HC-triggered NHE1 inhibition by AKT and antioxidant action that might involves mitochondrial dynamics improvement.

Reactive oxygen species generation by reverse electron transfer at mitochondrial complex I under simulated early reperfusion conditions

Ischemic tissues accumulate succinate, which is rapidly oxidized upon reperfusion, driving a burst of mitochondrial reactive oxygen species (ROS) generation that triggers cell death. In isolated mitochondria with succinate as the sole metabolic substrate under non-phosphorylating conditions, 90 % of ROS generation is from reverse electron transfer (RET) at the Q site of respiratory complex I (Cx-I). Together, these observations suggest Cx-I RET is the source of pathologic ROS in reperfusion injury. However, numerous factors present in early reperfusion may impact Cx-I RET, including: (i) High [NADH]; (ii) High [lactate]; (iii) Mildly acidic pH; (iv) Defined ATP/ADP ratios; (v) Presence of the nucleosides adenosine and inosine; and (vi) Defined free [Ca2+]. Herein, experiments with mouse cardiac mitochondria revealed that under simulated early reperfusion conditions including these factors, total mitochondrial ROS generation was only 56 ± 17 % of that seen with succinate alone (mean ± 95 % confidence intervals). Of this ROS, only 52 ± 20 % was assignable to Cx-I RET. A further 14 ± 7 % could be assigned to complex III, with the remainder (34 ± 11 %) likely originating from other ROS sources upstream of the Cx-I Q site. Together, these data suggest the relative contribution of Cx-I RET ROS to reperfusion injury may be overestimated, and other ROS sources may contribute a significant fraction of ROS in early reperfusion.

Patterns of left ventricular remodeling post-myocardial infarction, determinants, and outcome.

Left ventricular remodeling (LVR) after myocardial infarction (MI) can lead to heart failure, arrhythmia, and death. We aim to describe adverse LVR patterns at 6 months post-MI and their relationships with subsequent outcomes and to determine baseline. A multicenter cohort of 410 patients (median age 57 years, 87% male) with reperfused MI and at least 3 akinetic LV segments on admission was analyzed. All patients had transthoracic echocardiography performed 4 days and 6 months post-MI, and 214 also had cardiac magnetic resonance imaging performed on day 4. To predict LVR, machine learning methods were employed in order to handle many variables, some of which may have complex interactions. Six months post-MI, echocardiographic increases in LV end-diastolic volume (LVEDV), LV end-systolic volume (LVESV), and LV ejection fraction (LVEF) were 14.1% [interquartile range 0.0, 32.0], 5.0% [- 14.0, 25.8], and 8.7% [0.0, 19.4], respectively. At 6 months, ≥ 15% or 20% increases in LVEDV were observed in 49% and 42% of patients, respectively, and 37% had an LVEF < 50%. The rate of death or new-onset HF at the end of 5-year follow-up was 8.8%. Baseline variables associated with adverse LVR were determined best by random forest analysis and included stroke volume, stroke work, necrosis size, LVEDV, LVEF, and LV afterload, the latter assessed by Ea or Ea/Ees. In contrast, baseline clinical and biological characteristics were poorly predictive of LVR. After adjustment for predictive baseline variables, LV dilation > 20% and 6-month LVEF < 50% were significantly associated with the risk of death and/or heart failure: hazard ratio (HR) 2.12 (95% confidence interval (CI) 1.05-4.43; p = 0.04) and HR 2.68 (95% CI 1.20-6.00; p = 0.016) respectively. Despite early reperfusion and cardioprotective therapy, adverse LVR remains frequent after acute MI and is associated with a risk of death and HF. A machine learning approach identified and prioritized early variables that are associated with adverse LVR and which were mainly hemodynamic, combining LV volumes, estimates of systolic function, and afterload.