Abstract 106: CHANTER Syndrome: A Case Report Of A 59 Year Old Man With Positive Outcome

Introduction Cerebellar, Hippocampal, and Basal Nuclei Transient Edema with Restricted Diffusion (CHANTER) syndrome was first described in 2019 [1] as a pattern of radiographic findings that are distinct from ischemic, anoxic, or toxic brain injury. Pathophysiology is still uncertain, but some proposed theories include a primary metabolic etiology or a mitochondrial failure of gray matter. Clinically, patients typically present with altered level of consciousness. Radiographically, diffusion weighted imaging shows restriction in the bilateral hippocampi, bilateral cerebelli, and basal nuclei. The cerebral cortex, thalamus, and subcortical white matter are usually spared. Despite the morbid clinical picture on presenation, positive outcomes were reported with early intervention. We describe a case of CHANTER syndrome in a 59 year old man with history of illicit substance abuse. Methods Case report with electronic medical record review. Results 59‐year‐old man with history of illicit substance abuse including cocaine, opioid, and phencyclidine presented to the hospital after being found down at a drug store. Patient did not respond to Naloxone and was eventually intubated due to respiratory compromise. Non‐contrast CT head showed hypoattenuation of the bilateral cerebellar hemispheres with mild effacement of the fourth ventricle. MRI brain showed diffusion signal abnormalities with corresponding T2 FLAIR hyperintensities in the bilateral cerebellar hemispheres, bilateral hippocampi, and bilateral basal ganglia with some involvement of the left occipital lobe suggestive of CHANTER syndrome. As vasogenic edema worsened, hydrocephalus ensued requiring administration of hypertonic saline and eventual external ventricular drain (EVD) insertion in the neurocritical care unit. Despite initial improvement in his level of consciousness after the EVD insertion, his intracranial pressure (ICP) continued to increase and midazolam and ketamine infusion drips were added. A fine balance between lowering the ICP and avoiding respiratory suppresion with sedating infusions was maintained. Consecutive MRI brain images over the course of the following 4 weeks of his stay showed decrease of the abnormal diffusion weighted imaging signal along with improvement in his overall mental status and eventual discharge 12 weeks from his initial presentation. Conclusion This case further strengthens the relationship between CHANTER syndrome and illicit substance use as a likely etiology along with other cases in the literature. Aggressive management in the neurocritical care to control vasogenic edema and avoid ICP elevation is essential to give patients the highest chance of recovery. Clinical improvement At least partial reversal of the radiographic findings of CHANTER syndrome can be attained with treatment, however, unclear if complete reversal is possible

Abstract 182: Optimal Timeframe from Securing Mycotic Aneurysms to Cardiac Surgery: A Single Center Study

Introduction Infectious Intracranial Aneurysms (IIAs), commonly referred to as mycotic aneurysms, are a common sequela of infective endocarditis (IE). Approximately 65% of patients found to have IIAs also have IE, and IIAs occur in up to 10% of patients with IE. Currently, there are no guidelines for the management of IIAs due to the small sample size of observational studies and no randomized controlled studies. In addition to management techniques regarding IIAs, strategic cardiac valve surgery planning also remains imperative. Standard recommendations are to delay cardiac surgery by four weeks if patients are treated conservatively and if they remain stable. However, if one is able to embolize and secure IIAs, then that delay between endovascular therapy (EVT) and surgery may be shortened. We present a single‐center experience demonstrating the timing between securing mycotic aneurysms and cardiac surgery. Methods This is a single‐center retrospective observational study of patients admitted with IE who were found to have IIAs at our institute from 2016 to 2022. Descriptive statistics were performed using SAS statistical software and Microsoft Excel. Results Out of a total of 862 patients with IE, 25 patients (3.0%) were identified to have 41 IIAs (single aneurysm in 18 patients and multiple aneurysms in 7 patients). The median (IQR) age of our population was 45 (27‐65) years, with 28/41 (68.3%) male patients. The most common location of IIAs was the distal segments of the posterior and middle cerebral arteries in both groups. Of these 41 IIAs, 24/41 (58.5%) were ruptured and 17/41 (41.5%) were unruptured. A total of 14/24 (58.3%) ruptured IIAs were treated vs. none were treated in the unruptured IIAs group (P=0.001). A total of 8/41 (19.5%) IIAs were secured before undergoing cardiac valve surgery. The median (minimum‐maximum) number of days between securing aneurysms to valvular surgery was 18 (10‐29). Only 2/41 (4.9%) IIAs were detected following valvular surgery. Those were treated on day 3 and day 15 following surgery. There were 4/41 (9.7%) secured IIAs that did not undergo valvular surgery as they did not meet surgical criteria or had surgery planned at another admission. Conclusion Our study demonstrates that a timeframe of 2‐3 weeks from securing IIAs to cardiac surgery is considered safe. However, one should note that our cohort consists of a small sample size. Therefore, additional large multicenter observational studies are warranted to confirm these findings

Abstract 184: Comparing Characteristics and Outcomes of Ruptured and Unruptured Mycotic Aneurysms: A Single Center Study

Introduction Infectious intracranial aneurysms (IIAs), commonly referred to as mycotic aneurysms, are a common sequela of infective endocarditis (IE). Approximately 65% of patients found to have IIAs also have IE, and IIAs occur in up to 10% of patients with IE. Clinically, it is important to be able to identify IIAs as well as their etiologies to adequately manage these insidious vascular lesions. Mortality rates have been reported up to 30% for unruptured and 80% for ruptured mycotic aneurysms. With upcoming advances in the neuro‐endovascular field, there has been a surge in pursuing endovascular therapies to secure these aneurysms which have yielded positive outcomes. We present a single‐center experience describing the characteristics and outcomes of ruptured and unruptured IIAs. Methods This is a single‐center retrospective observational study of patients admitted with IE who developed IIAs and were admitted at our institute from 2016 to 2022. Descriptive statistics were performed using SAS statistical software and Microsoft Excel. Results Out of a total of 862 patients with IE, 25 patients (3.0%) were identified to have 41 IIAs (single aneurysm in 18 patients and multiple aneurysms in 7 patients). The median (IQR) age of our population was 45 (27‐65) years, with 28/41 (68.3%) male patients. The most common location of IIAs was the distal segments of the posterior and middle cerebral arteries in both groups. The overall mean (minimum‐maximum) size of all IIAs was 2.8 (0.2‐11) mm. Of these 41 IIAs, 24/41 (58.5%) were ruptured and 17/41 (41.5%) were unruptured. A total of 14/24 (58.3%) ruptured IIAs were treated vs. none were treated in the unruptured IIAs group (P=0.001). The average (minimum‐maximum; mm) size of ruptured IIAs was 3.3 (0.2‐11) vs. 2.1 (0.8‐5) in the unruptured IIAs group (P=0.324). More patients died while hospitalized with ruptured aneurysms vs unruptured aneurysms at 29.1% and 11.7%, respectively (P=0.18). Additionally, 16.7% of those in the ruptured group were discharged home, whereas 41.2% in the unruptured IIA group were discharged home (P=0.08). Conclusion This study emphasizes the significant mortality rate observed among patients with ruptured IIAs. Clinicians should remain vigilant when screening patients. Our study suggests that ruptured IIAs should be secured while unruptured IIAs may be monitored closely

Abstract 183: Characteristics and Outcomes of Treated and Untreated Mycotic Aneurysms: A Single Center Study

Introduction Infectious intracranial aneurysms (IIAs), commonly referred to as mycotic aneurysms, are a common sequela of infective endocarditis (IE). The morbidity rate is known to be about 80% in ruptured IIAs. Over the last decade, we have seen a rise in the utilization of endovascular therapies over conservative management for the treatment of IIAs with promising results. We present a single‐center experience describing the characteristics and outcomes of treated and untreated IIAs. Methods This is a single‐center retrospective observational study of patients admitted with IE who developed IIAs and were admitted at our institute from 2016 to 2022. Descriptive statistics were performed using SAS statistical software and Microsoft Excel. Results Out of a total of 862 patients with IE, 25 patients (3.0%) were identified to have 41 IIAs (single aneurysm in 18 patients and multiple aneurysms in 7 patients). The median (IQR) age of our population was 45 (27‐65) years, with 28/41 (68.3%) male patients. The overall mean (minimum‐maximum) size of all IIAs was 2.8 (0.2‐11) mm. The number of treated IIAs was 14/41 (34.1%) while 27/41 (65.9%) of IIAs were not intervened on. Among those IIAs treated, 92.8% were treated with an endovascular approach; 50% underwent onyx embolization, 28.6% underwent n‐BCA embolization, 14.2% underwent coil embolization, and 7.2% (n=1) underwent surgical intervention. The average (minimum‐maximum; mm) size of ruptured IIAs was 4.4 (1‐11) whereas the size of untreated IIAs was 2.0 (0.2‐9); (P=0.002). Among the treated group of IIAs, the majority were discharged home (21.4%) or discharged to facilities (78.6%). There was no in‐hospital mortality observed among the treated group. No IIAs were found to re‐rupture following embolization, and there was no change in any patient’s baseline neurologic examination following the embolization procedure. Conclusion Endovascular therapy is overall safe and effective in the management of IIAs and may be considered among patients with ruptured IIAs while accounting for their underlying comorbidities. Patients with secured IIAs are less likely to have in‐hospital mortality and are more likely to have better outcomes upon discharge. However, this may be influenced by case selection bias. Additional large center observational studies are warranted to confirm our findings

Antithrombotic Treatment for Stroke Prevention in Cervical Artery Dissection: The STOP-CAD Study.

Background: Small, randomized trials of cervical artery dissection (CAD) patients showed conflicting results regarding optimal stroke prevention strategies. We aimed to compare outcomes in patients with CAD treated with antiplatelets versus anticoagulation. Methods: This is a multi-center observational retrospective international study (16 countries, 63 sites) that included CAD patients without major trauma. The exposure was antithrombotic treatment type (anticoagulation vs. antiplatelets) and outcomes were subsequent ischemic stroke and major hemorrhage (intracranial or extracranial hemorrhage). We used adjusted Cox regression with Inverse Probability of Treatment Weighting (IPTW) to determine associations between anticoagulation and study outcomes within 30 and 180 days. The main analysis used an "as treated" cross-over approach and only included outcomes occurring on the above treatments. Results: The study included 3,636 patients [402 (11.1%) received exclusively anticoagulation and 2,453 (67.5%) received exclusively antiplatelets]. By day 180, there were 162 new ischemic strokes (4.4%) and 28 major hemorrhages (0.8%); 87.0% of ischemic strokes occurred by day 30. In adjusted Cox regression with IPTW, compared to antiplatelet therapy, anticoagulation was associated with a non-significantly lower risk of subsequent ischemic stroke by day 30 (adjusted HR 0.71 95% CI 0.45-1.12, p=0.145) and by day 180 (adjusted HR 0.80 95% CI 0.28-2.24, p=0.670). Anticoagulation therapy was not associated with a higher risk of major hemorrhage by day 30 (adjusted HR 1.39 95% CI 0.35-5.45, p=0.637) but was by day 180 (adjusted HR 5.56 95% CI 1.53-20.13, p=0.009). In interaction analyses, patients with occlusive dissection had significantly lower ischemic stroke risk with anticoagulation (adjusted HR 0.40 95% CI 0.18-0.88) (Pinteraction=0.009). Conclusions: Our study does not rule out a benefit of anticoagulation in reducing ischemic stroke risk, particularly in patients with occlusive dissection. If anticoagulation is chosen, it seems reasonable to switch to antiplatelet therapy before 180 days to lower the risk of major bleeding. Large prospective studies are needed to validate our findings