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Subarachnoid hemorrhage (SAH) is a devastating type of stroke, leading to high mortality and morbidity rates. Cerebral vasospasm and delayed cerebral ischemia (DCI) are common complications following SAH that contribute significantly to the poor outcomes observed in these patients. Intrathecal (IT) nicardipine delivered via an existing external ventricular drain is an off‐label intervention that has been shown to be correlated with reduced DCI and improved patient outcomes. The current study aims to characterize the population pharmacokinetic (popPK) properties of intermittent IT nicardipine. Following informed consent, serial cerebrospinal fluid (CSF) samples were obtained from 16 SAH patients (50.4 ± 9.3 years old; 13 females) treated with IT nicardipine every 6 h (q6h, n = 8) or every 8 h (q8h, n = 8) for an average of 72 ± 21 doses. High‐performance liquid chromatography was used to quantify CSF concentration from each sample. Our popPK analysis showed that the CSF pharmacokinetics of IT nicardipine in the cohort was adequately described by a two‐compartment model with a lag time. Model parameter estimates were reliable (relative standard error <50%). Intracranial pressure influenced both the total clearance and the central volume of nicardipine (i.e., negative correlation, P <−.001). Calculated PK parameters were similar between q6h and q8h dosing regimens. Despite a small cohort of SAH patients, we successfully developed a popPK model to describe the nicardipine disposition kinetics in the CSF following IT administration. These findings may help inform future clinical trials designed to examine the optimal dosing of IT nicardipine. [ABSTRACT FROM AUTHOR]

Although multilayer analytical models have been proposed to enhance brain sensitivity of diffuse correlation spectroscopy (DCS) measurements of cerebral blood flow, the traditional homogeneous model remains dominant in clinical applications. Rigorous in vivo comparison of these analytical models is lacking. We compare the performance of different analytical models to estimate a cerebral blood flow index (CBFi) with DCS in adults. Resting-state data were obtained on a cohort of 20 adult patients with subarachnoid hemorrhage. Data at 1 and 2.5 cm source-detector separations were analyzed with the homogenous, two-layer, and three-layer models to estimate scalp blood flow index and CBFi. The performance of each model was quantified via fitting convergence, fit stability, brain-to-scalp flow ratio (BSR), and correlation with transcranial Doppler ultrasound (TCD) measurements of cerebral blood flow velocity in the middle cerebral artery (MCA). The homogeneous model has the highest pass rate (100%), lowest coefficient of variation (CV) at rest (median [IQR] at 1 Hz of 0.18 [0.13, 0.22]), and most significant correlation with MCA blood flow velocities (Rs = 0.59, p = 0.010) compared with both the two- and three-layer models. The multilayer model pass rate was significantly correlated with extracerebral layer thicknesses. Discarding datasets with non-physiological BSRs increased the correlation between DCS measured CBFi and TCD measured MCA velocities for all models. We found that the homogeneous model has the highest pass rate, lowest CV at rest, and most significant correlation with MCA blood flow velocities. Results from the multilayer models should be taken with caution because they suffer from lower pass rates and higher coefficients of variation at rest and can converge to non-physiological values for CBFi. Future work is needed to validate these models in vivo, and novel approaches are merited to improve the performance of the multimodel models. [ABSTRACT FROM AUTHOR]

This document is a reply to a comment on a previous manuscript regarding the pharmacokinetics of nicardipine in patients with subarachnoid hemorrhage. The authors address some details that were omitted from the original manuscript, such as sample storage and patient outcomes. They explain that the purpose of their study was to determine the pharmacokinetics of nicardipine and that reporting patient outcomes in a small cohort may lead to misinterpretation. They also discuss the relevance of another study and mention the dosing regimen used in a clinical trial. The authors conclude by stating that larger and more rigorously designed studies are needed to develop an optimal dosing strategy for intrathecal nicardipine. [Extracted from the article]

Disclaimer: In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time., Purpose: Subarachnoid hemorrhage (SAH) is a rare but life-threatening clinical event for pediatric patients. Cerebral vasospasm is a common complication of SAH that often leads to poor outcomes. This case report describes the use of dual intraventricular (IVT) vasodilators in a pediatric patient., Summary: An 11-year-old male presented with traumatic diffuse SAH and cranial vasospasm. Despite treatment with IVT nicardipine, intravenous (IV) milrinone by continuous infusion, enteral nimodipine, and intraarterial verapamil and milrinone given during digital subtraction angiography, transcranial Doppler (TCD) mean velocities continued to rise. IVT milrinone was then added to IVT nicardipine and IV milrinone. The combination of IVT nicardipine, IV milrinone, and rescue therapy with IVT milrinone was continued for a total of 7 days. TCD mean velocities decreased into the mild to moderate range within 2 days of the patient receiving this combined regimen and remained globally low thereafter., Conclusion: This case illustrates the potential benefit of using dual IVT vasodilators to improve outcomes for pediatric patients with refractory cerebral vasospasm., (© American Society of Health-System Pharmacists 2024. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Background: Atrial fibrillation (AF) associated ischemic stroke is associated with worse functional outcomes, less effective recanalization, and increased rates of hemorrhagic complications after intravenous thrombolysis (IVT). Conversely, AF is not associated with hemorrhagic complications or functional outcomes in patients undergoing mechanical thrombectomy (MT). This differential effect of MT and IVT in AF associated stroke raises the question of whether bridging thrombolysis increases hemorrhagic complications in AF patients undergoing MT., Methods: This international cohort study of 22 comprehensive stroke centers analyzed patients with large vessel occlusion (LVO) undergoing MT between June 1, 2015 and December 31, 2020. Patients were divided into four groups based on comorbid AF and IVT exposure. Baseline patient characteristics, complications, and outcomes were reported and compared., Results: 6461 patients underwent MT for LVO. 2311 (35.8%) patients had comorbid AF. In non-AF patients, bridging therapy improved the odds of good 90 day functional outcomes (adjusted OR (aOR) 1.29, 95% CI 1.03 to 1.60, p=0.025) and did not increase hemorrhagic complications. In AF patients, bridging therapy led to significant increases in symptomatic intracranial hemorrhage and parenchymal hematoma type 2 (aOR 1.66, 1.07 to 2.57, p=0.024) without any benefit in 90 day functional outcomes. Similar findings were noted in a separate propensity score analysis., Conclusion: In this large thrombectomy registry, AF patients exposed to IVT before MT had increased hemorrhagic complications without improved functional outcomes, in contrast with non-AF patients. Prospective trials are warranted to assess whether AF patients represent a subgroup of LVO patients who may benefit from a direct to thrombectomy approach at thrombectomy capable centers., Competing Interests: Competing interests: RMS: consulting and teaching agreements with Penumbra, Abbott, Medtronic, InNeuroCo, and Cerenovus. MNP: travel grants/honoraria from Phenox, Stryker, and Siemens. ASA: consultant for Balt, Johnson and Johnson, Leica, Medtronic, Microvention, Penumbra, Scientia, Siemens, and Stryker; research support for Cerenovus, Microvention, Penumbra, and Siemens; and shareholder of Bendit, Cerebrotech, Endostream, Magneto, Marblehead, Neurogami, Serenity, Synchron, Triad Medical, and Vascular Simulations. LE: consultant for Balt, Cerenovuc, Medtronic, MicroVention, Penumbra, Sequent, and Stryker; and research support for Siemens. PJ: consultant for Medtronics and Microvention. AMS: consultant for Penumbra, Microvention, and Pulsar Vascular; and travel grants/honoraria from Penumbra, Pulsar Vascular, Microvention, and Stryker. KMF, JM, PK, and RDL are on the editorial board of Journal of Neurointerventional Surgery., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)