Chemical angioplasty vs. balloon plus chemical angioplasty for delayed cerebral ischemia: a pilot study of PbtO2 outcomes

BACKGROUND

Delayed cerebral ischaemia (DCI) is a major cause of morbidity and mortality after aneurysmal subarachnoid haemorrhage (aSAH). Chemical angioplasty (CA) and transluminal balloon angioplasty (TBA) are used to treat patients with refractory vasospasm causing DCI. Multi-modal monitoring including brain tissue oxygenation (PbtO2) is routinely used at this centre for early detection and management of DCI following aSAH. In this single-centre pilot study, we are comparing these two treatment modalities and their effects on PbtO2.

METHODS

Retrospective case series of patients with DCI who had PbtO2 monitoring as part of their multimodality monitoring and underwent either CA or TBA combined with CA. PbtO2 values were recorded from intra-parenchymal Raumedic NEUROVENT-PTO® probes. Data were continuously collected and downloaded as second-by-second data. Comparisons were made between pre-angioplasty PbtO2 and post-angioplasty PbtO2 median values (4 h before angioplasty, 4 h after and 12 h after).

RESULTS

There were immediate significant improvements in PbtO2 at the start of intervention in both groups. PbtO2 then increased by 13 mmHg in the CA group and 15 mmHg in the TBA plus CA group in the first 4 h post-intervention. This improvement in PbtO2 was sustained for the TBA plus CA group but not the CA group.

CONCLUSION

Combined balloon plus chemical angioplasty results in more sustained improvement in brain tissue oxygenation compared with chemical angioplasty alone. Our findings suggest that PbtO2 is a useful tool for monitoring the response to angioplasty in vasospasm.

Contemporary management of aneurysmal subarachnoid haemorrhage. An update for the intensivist

Aneurysmal subarachnoid haemorrhage (aSAH) is a rare yet profoundly debilitating condition associated with high global case fatality and morbidity rates. The key determinants of functional outcome include early brain injury, rebleeding of the ruptured aneurysm and delayed cerebral ischaemia. The only effective way to reduce the risk of rebleeding is to secure the ruptured aneurysm quickly. Prompt diagnosis, transfer to specialized centers, and meticulous management in the intensive care unit (ICU) significantly improved the prognosis of aSAH. Recently, multimodality monitoring with specific interventions to correct pathophysiological imbalances has been proposed. Vigilance extends beyond intracranial concerns to encompass systemic respiratory and haemodynamic monitoring, as derangements in these systems can precipitate secondary brain damage. Challenges persist in treating aSAH patients, exacerbated by a paucity of robust clinical evidence, with many interventions showing no benefit when tested in rigorous clinical trials. Given the growing body of literature in this field and the issuance of contemporary guidelines, our objective is to furnish an updated review of essential principles of ICU management for this patient population. Our review will discuss the epidemiology, initial stabilization, treatment strategies, long-term prognostic factors, the identification and management of post-aSAH complications. We aim to offer practical clinical guidance to intensivists, grounded in current evidence and expert clinical experience, while adhering to a concise format.

Advances in biomarkers for vasospasm - Towards a future blood-based diagnostic test

Objective

Cerebral vasospasm and the resultant delayed cerebral infarction is a significant source of mortality following aneurysmal SAH. Vasospasm is currently detected using invasive or expensive imaging at regular intervals in patients following SAH, thus posing a risk of complications following the procedure and financial burden on these patients. Currently, there is no blood-based test to detect vasospasm.

Methods

PubMed, Web of Science, and Embase databases were systematically searched to retrieve studies related to cerebral vasospasm, aneurysm rupture, and biomarkers. The study search dated from 1997 to 2022. Data from eligible studies was extracted and then summarized.

Results

Out of the 632 citations screened, only 217 abstracts were selected for further review. Out of those, only 59 full text articles met eligibility and another 13 were excluded.

Conclusions

We summarize the current literature on the mechanism of cerebral vasospasm and delayed cerebral ischemia, specifically studies relating to inflammation, and provide a rationale and commentary on a hypothetical future bloodbased test to detect vasospasm. Efforts should be focused on clinical-translational approaches to create such a test to improve treatment timing and prediction of vasospasm to reduce the incidence of delayed cerebral infarction.

Prediction of delayed cerebral ischemia followed aneurysmal subarachnoid hemorrhage. A machine-learning based study

INTRODUCTION

Delayed Cerebral Ischemia (DCI) is a significant complication following aneurysmal subarachnoid hemorrhage (aSAH) that can lead to poor outcomes. Machine learning techniques have shown promise in predicting DCI and improving risk stratification.

METHODS

In this study, we aimed to develop machine learning models to predict the occurrence of DCI in patients with aSAH. Patient data, including various clinical variables and co-factors, were collected. Six different machine learning models, including logistic regression, multilayer perceptron, decision tree, random forest, gradient boosting machine, and extreme gradient boosting (XGB), were trained and evaluated using performance metrics such as accuracy, area under the curve (AUC), precision, recall, and F1 score.

RESULTS

After data augmentation, the random forest model demonstrated the best performance, with an AUC of 0.85. The multilayer perceptron neural network model achieved an accuracy of 0.93 and an F1 score of 0.85, making it the best performing model. The presence of positive clinical vasospasm was identified as the most important feature for predicting DCI.

CONCLUSIONS

Our study highlights the potential of machine learning models in predicting the occurrence of DCI in patients with aSAH. The multilayer perceptron model showed excellent performance, indicating its utility in risk stratification and clinical decision-making. However, further validation and refinement of the models are necessary to ensure their generalizability and applicability in real-world settings. Machine learning techniques have the potential to enhance patient care and improve outcomes in aSAH, but their implementation should be accompanied by careful evaluation and validation.

"Aneurysmal Subarachnoid Hemorrhage and Cocaine Consumption: A Systematic Review and Metanalysis"

BACKGROUND

The use of cocaine can lead to a variety of neurologic complications, including cerebral vasoconstriction, ischemia, aneurysm formation, and aneurysm rupture. A previous study has shown that cocaine use is associated with an increased risk of subarachnoid hemorrhage (SAH). This study conducted a systematic review and meta-analysis of observational studies to assess the association between cocaine use and the risk of poor neurological outcomes and mortality in patients with SAH.

METHODS

A systematic review and meta-analysis were performed following the meta-analysis of observational studies in epidemiology (MOOSE) declaration for systematic reviews and the Cochrane Manual of Systematic Reviews and Meta-Analyses guidelines. Randomized controlled trials (RCTs), nonrandomized clinical trials, and prospective and retrospective cohort studies that reported data about adults who suffered Aneurysmal Subarachnoid Hemorrhage (aSAH) after having consumed cocaine recreationally were included. Variables such as mortality, vasospasm, seizures, re-bleeding, and complications were analyzed.

RESULTS

After a thorough selection process, 14 studies involving 116,141 patients, of which 2227 had a history of cocaine consumption, were included in the analysis. There was a significant increase in overall unfavorable outcomes in aSAH patients with a history of cocaine use (OR 5.51 CI 95% [4.26-7.13] P = <0.0001; I2 = 78%), with higher mortality and poor neurologic outcomes. There were no significant differences in the risk of hydrocephalus, seizures, or re-bleeding. Cocaine use was found to increase the risk of vasospasm and overall complications.

CONCLUSIONS

This study insinuates that cocaine use is associated with worse clinical outcomes in aSAH patients. Despite the cocaine users did not exhibit a higher risk of certain complications such as hydrocephalus and seizures, they had an increased risk of vasospasm and overall complications. These findings highlight the importance of addressing the issue of cocaine consumption as a primary preventive measure to decrease the incidence of aSAH and improve patient outcomes.

Non-invasive Auricular Vagus nerve stimulation for Subarachnoid Hemorrhage (NAVSaH): Protocol for a prospective, triple-blinded, randomized controlled trial

Background

Inflammation has been implicated in driving the morbidity associated with subarachnoid hemorrhage (SAH). Despite understanding the important role of inflammation in morbidity following SAH, there is no current effective way to modulate this deleterious response. There is a critical need for a novel approach to immunomodulation that can be safely, rapidly, and effectively deployed in SAH patients. Vagus nerve stimulation (VNS) provides a non-pharmacologic approach to immunomodulation, with prior studies demonstrating VNS can reduce systemic inflammatory markers, and VNS has had early success treating inflammatory conditions such as arthritis, sepsis, and inflammatory bowel diseases. The aim of the Non-invasive Auricular Vagus nerve stimulation for Subarachnoid Hemorrhage (NAVSaH) trial is to translate the use of non-invasive transcutaneous auricular VNS (taVNS) to spontaneous SAH, with our central hypothesis being that implementing taVNS in the acute period following spontaneous SAH attenuates the expected inflammatory response to hemorrhage and curtails morbidity associated with inflammatory-mediated clinical endpoints.

Materials and methods

The overall objectives for the NAHSaH trial are to 1) Define the impact that taVNS has on SAH-induced inflammatory markers in the plasma and cerebrospinal fluid (CSF), 2) Determine whether taVNS following SAH reduces radiographic vasospasm, and 3) Determine whether taVNS following SAH reduces chronic hydrocephalus. Following presentation to a single enrollment site, enrolled SAH patients are randomly assigned twice daily treatment with either taVNS or sham stimulation for the duration of their intensive care unit stay. Blood and CSF are drawn before initiation of treatment sessions, and then every three days during a patient's hospital stay. Primary endpoints include change in the inflammatory cytokine TNF-α in plasma and cerebrospinal fluid between day 1 and day 13, rate of radiographic vasospasm, and rate of requirement for long-term CSF diversion via a ventricular shunt. Secondary outcomes include exploratory analyses of a panel of additional cytokines, number and type of hospitalized acquired infections, duration of external ventricular drain in days, interventions required for vasospasm, continuous physiology data before, during, and after treatment sessions, hospital length of stay, intensive care unit length of stay, and modified Rankin Scale score (mRS) at admission, discharge, and each at follow-up appointment for up to two years following SAH.

Discussion

Inflammation plays a central role in morbidity following SAH. This NAVSaH trial is innovative because it diverges from the pharmacologic status quo by harnessing a novel non-invasive neuromodulatory approach and its known anti-inflammatory effects to alter the pathophysiology of SAH. The investigation of a new, effective, and rapidly deployable intervention in SAH offers a new route to improve outcomes following SAH.

Trial registration

Clinical Trials Registered, NCT04557618. Registered on September 21, 2020, and the first patient was enrolled on January 4, 2021.

Comparison of efficacy between clazosentan and fasudil hydrochloride-based management of vasospasm after subarachnoid hemorrhage focusing on older and WFNS grade V patients: a single-center experience in Japan

Subarachnoid hemorrhage often leads to poor outcomes owing to vasospasm, even after successful aneurysm treatment. Clazosentan, an endothelin receptor inhibitor, has been proven to be an effective treatment for vasospasms in a Japanese randomized controlled trial. However, its efficacy in older patients (≥ 75 years old) and those with World Federation of Neurosurgical Societies (WFNS) grade V has not been demonstrated. We retrospectively evaluated the efficacy of clazosentan in older patients and those with WFNS grade V, using real-world data. Patients with subarachnoid hemorrhage treated before and after the introduction of clazosentan were retrospectively evaluated. The patients were categorized into two groups (clazosentan era versus pre-clazosentan era), in which vasospasm management and outcomes were compared. Vasospasms were managed with fasudil hydrochloride-based (pre-clazosentan era) or clazosentan-based treatment (clazosentan era). Seventy-eight patients were included in this study: the clazosentan era (n = 32) and pre-clazosentan era (n = 46). Overall, clazosentan significantly reduced clinical vasospasms (clazosentan era: 31.3% versus pre-clazosentan era: 60.9%, p = 0.01), delayed cerebral ischemia (DCI) (9.4% versus 39.1%, p = 0.004), and vasospasm-related morbidity and mortality (M/M) (3.1% versus 19.6%, p = 0.03). In subgroup analysis of older patients or those with WFNS grade V, no significant difference was observed in clinical outcomes, although both DCI and vasospasm-related M/M were lower in the clazosentan era. Clazosentan was more effective than fasudil-based management in preventing DCI and reducing vasospasm-related M/M. Clazosentan could be used safely in older patients and those with WFNS grade V, although clinical outcomes in these patients were comparable to those of conventional treatment.

Effectiveness of Cerebrospinal Fluid Lumbar Drainage Among Patients with Aneurysmal Subarachnoid Hemorrhage: An Updated Systematic Review and Meta-Analysis

INTRODUCTION

Cerebral vasospasm in patients after aneurysmal subarachnoid hemorrhage (aSAH) continues to be a major source of morbidity despite significant clinical and basic science research. The removal of blood and its degradation products from the subarachnoid space through prophylactic lumbar drainage (LD) is a favorable option. However, several studies have delivered conflicting conclusions on its efficacy after aSAH.

METHODS

Systematic searches of Medline, Embase, and Cochrane Central Register of Controlled Trials were performed. The primary outcome was a good functional outcome (modified Rankin scale score, 0-2). Secondary outcomes included symptomatic vasospasm, secondary cerebral infarction, and mortality.

RESULTS

A total of 14 studies reporting on 2473 patients with aSAH were included in the meta-analysis. Compared with the non-LD group, no significant differences were found in the rates of good functional outcomes in the LD group at discharge to 1 month (risk ratio [RR], 1.28; 95% confidence interval [CI], 0.64-2.58) or at 6 months (RR, 1.12; 95% CI, 0.97-1.41). These findings were consistent in the subgroup analyses of only randomized controlled trials or observational studies. LD was associated with lower rates of symptomatic vasospasm (RR, 0.61; 95% CI, 0.48-0.77), secondary cerebral infarction (RR, 0.59; 95% CI, 0.45-0.79), and mortality at discharge to 1 month (RR, 0.58; 95% CI, 0.41-0.82). The effect on mortality diminished at 6 months (RR, 0.70; 95% CI, 0.34-1.45). However, when analyzing only randomized controlled trials, the benefit of LD on lower rates of mortality continued even at 6 months (RR, 0.75; 95% CI, 0.58-0.99).

CONCLUSIONS

For aSAH patients, the use of LD is associated with benefits in the rates of vasospasm, secondary cerebral infarctions, and mortality, without an increased risk of adverse events.

Point-of-care brain ultrasound and transcranial doppler or color-coded doppler in critically ill neonates and children

Point-of-care brain ultrasound and transcranial doppler or color-coded doppler is being increasingly used as an essential diagnostic and monitoring tool at the bedside of critically ill neonates and children. Brain ultrasound has already established as a cornerstone of daily practice in the management of the critically ill newborn for diagnosis and follow-up of the most common brain diseases, considering the easiness to insonate the brain through transfontanellar window. In critically ill children, doppler based techniques are used to assess cerebral hemodynamics in acute brain injury and recommended for screening patients suffering from sickle cell disease at risk for stroke. However, more evidence is needed regarding the accuracy of doppler based techniques for non-invasive estimation of cerebral perfusion pressure and intracranial pressure, as well as regarding the accuracy of brain ultrasound for diagnosis and monitoring of acute brain parenchyma alterations in children. This review is aimed at providing a comprehensive overview for clinicians of the technical, anatomical, and physiological basics for brain ultrasonography and transcranial doppler or color-coded doppler, and of the current status and future perspectives of their clinical applications in critically ill neonates and children.

CONCLUSION

In critically ill neonates, brain ultrasound for diagnosis and follow-up of the most common cerebral pathologies of the neonatal period may be considered the standard of care. Data are needed about the possible role of doppler techniques for the assessment of cerebral perfusion and vasoreactivity of the critically ill neonate with open fontanelles. In pediatric critical care, doppler based techniques should be routinely adopted to assess and monitor cerebral hemodynamics. New technologies and more evidence are needed to improve the accuracy of brain ultrasound for the assessment of brain parenchyma of critically ill children with fibrous fontanelles.

WHAT IS KNOWN

• In critically ill neonates, brain ultrasound for early diagnosis and follow-up of the most common cerebral and neurovascular pathologies of the neonatal period is a cornerstone of daily practice. In critically ill children, doppler-based techniques are more routinely used to assess cerebral hemodynamics and autoregulation after acute brain injury and to screen patients at risk for vasospasm or stroke (e.g., sickle cell diseases, right-to-left shunts).

WHAT IS NEW

• In critically ill neonates, research is currently focusing on the use of novel high frequency probes, even higher than 10 MHz, especially for extremely preterm babies. Furthermore, data are needed about the role of doppler based techniques for the assessment of cerebral perfusion and vasoreactivity of the critically ill neonate with open fontanelles, also integrated with a non-invasive assessment of brain oxygenation. In pediatric critical care, new technologies should be developed to improve the accuracy of brain ultrasound for the assessment of brain parenchyma of critically ill children with fibrous fontanelles. Furthermore, large multicenter studies are needed to clarify role and accuracy of doppler-based techniques to assess cerebral perfusion pressure and its changes after treatment interventions.

Interventional Treatment of Symptomatic Vasospasm in the Setting of Traumatic Brain Injury: A Systematic Review of Reported Cases

Traumatic subarachnoid hemorrhage (tSAH) is frequently comorbid with traumatic brain injury (TBI) and may induce secondary injury through vascular changes such as vasospasm and subsequent delayed cerebral ischemia (DCI). While aneurysmal SAH is well studied regarding vasospasm and DCI, less is known regarding tSAH and the prevalence of vasospasm and DCI, the consequences of vasospasm in this setting, when treatment is indicated, and which management strategies should be implemented. In this article, a systematic review of the literature that was conducted for cases of symptomatic vasospasm in patients with TBI is reported, association with tSAH is reported, risk factors for vasospasm and DCI are summarized, and commonalities in diagnosis and management are discussed. Clinical characteristics and treatment outcomes of 38 cases across 20 studies were identified in which patients with TBI with vasospasm underwent medical or endovascular management. Of the patients with data available for each category, the average age was 48.7 ± 20.3 years (n = 31), the Glasgow Coma Scale score at presentation was 10.6 ± 4.5 (n = 35), and 100% had tSAH (n = 29). Symptomatic vasospasm indicative of DCI was diagnosed on average at postinjury day 8.4 ± 3.0 days (n = 30). Of the patients, 56.6% (n = 30) had a new ischemic change associated with vasospasm confirming DCI. Treatment strategies are discussed, with 11 of 12 endovascularly treated and 19 of 26 medically treated patients surviving to discharge. tSAH is associated with vasospasm and DCI in moderate and severe TBI, and patients with clinical and radiographic evidence of symptomatic vasospasm and subsequent DCI may benefit from endovascular or medical management strategies.

Ultrastructural changes of vascular smooth muscle cells and resistance to vasospasm treatment in femoral arteries of an arteriosclerotic rat model

The objective of this study was to establish an animal model of arteriosclerosis for assessing vasospasm and to investigate the relationship between arteriosclerosis and vasospasm. Twelve-week-old male Sprague-Dawley rats were fed a diet supplemented with adenine and vitamin D (adenine/vitD). Body weight, blood, and femoral artery histopathology were assessed at 2, 4, and 6 weeks. Change in the femoral artery was examined by transmission electron microscope (TEM). Vasospasm was induced by administering epinephrine extravascularly into the femoral artery and released by the treatment with lidocaine as a vasodilator. During this period, the extravascular diameter and blood flow were measured. The rats in the adenine/vitD group developed renal dysfunction, uremia, hyperphosphatemia, and elevated serum alkaline phosphatase. Histological and TEM analyses of the femoral arteries in the treated rats revealed the degeneration of elastic fibers and extensive calcification of the tunica media and intima. Vascular smooth muscles were degenerated and osteoblasts were developed, resulting in calcified arteriosclerosis. Vasospasm in arteriosclerotic arteries was detected; however, vasodilation as well as an increase in the blood flow was not observed. This study revealed the development of vasospasm in the femoral arteries of the arteriosclerotic rats and, a conventional vasodilator did not release the vasospasm.

Hepatic artery vasospasm masquerading as early hepatic artery thrombosis in progressive familial intrahepatic cholestasis 3: a case report

Post-liver transplant (LT) hepatic artery vasospasm is a vascular complication that is not well recognized and its incidence is not known. As a possible sequela to vasospasm, hepatic artery thrombosis is the second major cause of allograft failure after primary nonfunction and its reported incidence is 2.9% in adults and 8.3% in pediatric LT. Lacuna in knowledge regarding early hepatic artery vasospasm post-LT makes it a difficult condition to diagnose and treat, as the initial ischemic insult on graft can have devastating consequences. We report a case of pediatric progressive familial intrahepatic cholestasis type 3-related chronic liver disease who underwent cadaveric orthotopic LT and postoperatively developed fever, worsening hypotension, and elevated liver enzymes with an absence of arterial flow in intrahepatic branches on Doppler ultrasound. Suspecting early hepatic artery thrombosis, the patient was re-explored and the graft hepatic artery was found to be in a state of vasospasm. Following the infusion of intra-arterial papaverine, urokinase, and intravenous nicorandil, there was an improvement in blood flow. The patient responded well and was discharged on postoperative day 23 with normal liver enzymes.

Stellate Ganglion Block in Subarachnoid Hemorrhage: A Promising Protective Measure Against Vasospasm?

BACKGROUND

Stellate ganglion block (SGB) may have protective effects in patients at risk of vasospasm following subarachnoid hemorrhage (SAH) due to reduced sympathetic activity. However, the safety and clinical outcomes of SGB in this scenario are not definitively known. The objective was to evaluate the safety, clinical outcomes, and cerebral blood flow velocity in patients submitted to SGB or cervical sympathectomy with SAH.

METHODS

Following Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, a systematic review and meta-analysis of studies investigating SGB or cervical sympathectomy use in SAH were conducted. PubMed, Cochrane Library, and Embase were evaluated. Patients with mRS from 0 to 2, GOS from 4 to 5, or symptom resolution were considered favorable clinical outcomes. Related mortality was defined as death by vasospasm or delayed cerebral ischemia.

RESULTS

The analysis included 8 studies comprising 182 patients. Only 2 studies employed SGB prophylactically. The results revealed favorable outcomes in 52% of patients (95% CI: 37%-65%). The overall incidence of complications was 2% (95% CI: 0% -26%). The mortality rate was 13% (95% CI: 7%-21%), with a vasospasm-related mortality rate of 11% (95% CI: 2%-20%). A decrease of cerebral blood flow velocity was reported in 4 studies.

CONCLUSIONS

The notable reduction in cerebral blood flow velocity following SGB, alongside positive outcomes and a low occurrence of mortality and complications, highlights its significance as a therapeutic intervention for vasospasm following SAH. While the number of studies evaluating SGB as a preventive measure is limited, the promising results emphasize the importance of future research.

Ferroptosis as a Therapeutic Target in Subarachnoid Hemorrhage

Subarachnoid hemorrhage (SAH) is a cerebrovascular disorder with significant mortality and morbidity. Neural injury in SAH is mediated through a variety of pathophysiological processes. Currently available treatments are either nonspecific in targeting the basic pathophysiological mechanisms that result in neural damage in SAH, or merely focus on vasospasm. Ferroptosis is a type of programmed iron dependent cell death, which has received attention due to its possible role in neural injury in SAH. Herein, we review how intracellular iron overload mediates the production of reactive free radicals and lipid peroxidation through a variety of biochemical pathways in SAH. This in turn results in induction of ferroptosis, as well as exacerbation of vasospasm. We also discuss several therapeutic agents that have been shown to inhibit ferroptosis through targeting different steps of the process. Such agents have proven effective in ameliorating vasospasm, neural damage, and neurobehavioral outcomes in animal models of SAH. Human studies to test the safety and efficacy of intrathecal or parenteral administration of the inhibitors of ferroptosis in improving outcomes of SAH patients are warranted. There are currently a few ongoing clinical trials pursuing this therapeutic concept, the results of which will be critical to determine the value of ferroptosis as a novel therapeutic target in SAH.

Effect of Intrathecal Urokinase Infusion on Cerebral Vasospasm After Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

Vasospasm following an aneurysmal subarachnoid hemorrhage (SAH) causes serious neurological complications, despite surgical clipping of the aneurysm. Intrathecal urokinase (UK) infusion has been shown to effectively prevent symptomatic vasospasm in patients who have undergone endovascular obliteration of the ruptured aneurysms.

OBJECTIVE

To investigate whether intrathecal UK infusion can prevent symptomatic vasospasm in patients undergoing surgical or endovascular treatment.

METHODS

A total of 90 patients with severe aneurysmal SAH were enrolled and assigned to a surgical neck clipping (n = 56) or an endovascular coil embolization (n = 34) groups. After treatment, UK infusion from the lumbar drain was repeated in 32 patients in the surgical neck clipping group (group B) and all in the endovascular coil embolization group (group C) until complete resolution of the SAH was observed on computed tomography. The remaining 24 of the surgical neck clipping group, without UK infusion, were assigned to group A.

RESULTS

Symptomatic vasospasm occurred in 7 (29.2%) patients in group A, 2 (6.3%) in group B, and none in group C (group A vs. group B [P = 0.02]; group B vs. group C [P = 0.14]). Excellent clinical outcomes (modified Rankin score, 0 or 1) were observed in 37.5%, 59.4%, and 76.5% of patients in group A, B, and C, respectively (group A vs. group B [P = 0.11]).

CONCLUSION

Clearance of SAH via intrathecal UK infusion significantly reduced symptomatic vasospasm in patients in both UK groups, resulting in better clinical outcomes.

Migrainous infarction

Migrainous infarction is defined as a migraine attack occurring as migraine with aura, typical of the patient's previous attacks, except that one or more aura symptoms persist for >60min, and neuroimaging demonstrates ischemic infarct in the relevant area. To better understand migrainous infarction, one must disentangle the complex interactions between migraine and stroke. In this chapter, we first discuss the migraine-stroke association in sections including "Increased Risks of Stroke and Subclinical Infarcts in Patients With Migraine," "Migrainous Headache Cooccurring or Triggered by Ischemic Stroke," "Stroke Progression in Patients With Migraine," and "Clinic Conditions Associated With Higher Risks of Both Migraine and Stroke." As an extreme example of migraine-stroke association, the annual incidence of migrainous infarction was reported to be 0.80/100,000/year, with the incidence in females nearly twofold that of male patients. Patients diagnosed with migrainous infarction are typically younger (average age 29-39 in case series), have fewer traditional vascular risk factors, and have more favorable prognosis compared to strokes from traditional risk factors. Thorough evaluation is recommended to rule out other etiologies of stroke. Patients diagnosed with migrainous infarction should receive antiplatelet therapy and migraine preventive therapy to avoid future events. Vasoactive medications, including triptans and ergots, should be avoided.

Ponatinib-Related Vasospastic Angina

Tyrosine kinase inhibitors (TKIs) are essential drugs for chronic myeloid leukemia and Philadelphia chromosome-positive acute lymphoblastic leukemia. Cardiovascular or arteriothrombotic adverse events have been reported in patients treated with TKIs. We report 3 cases of Ponatinib-related vasospastic angina, in which prophylactic administration of nitrates or calcium channel blockers was effective.

Use of a stent-retriever for treatment of iatrogenic vasospasm secondary to mechanical thrombectomy

The treatment strategy for iatrogenic intracranial vasospasm has not been established. We reported a rare case of stent-retriever use for the treatment of iatrogenic vasospasm after mechanical thrombectomy. The patient presented acute ischemic stroke due to the occlusion of the left middle cerebral artery (MCA). The patient underwent a successfully mechanical thrombectomy, however, severe stenosis was visualized in MCA, which was considered to be an iatrogenic mechanical vasospasm. This vasospasm was successfully treated with the Solitaire stent device, and the patient recovered from ischemic symptoms. A stent-retriever is a safe and effective treatment for iatrogenic vasospasm after mechanical thrombectomy.

Vascular imaging immediately after tourniquet removal does not increase vasospasm risk

BACKGROUND

Prehospital tourniquet use is now standard in trauma patients with diagnosed or suspected extremity vascular injuries. Tourniquet-related vasospasm is an understudied phenomenon that may confound management by causing erroneous arterial pressure indices (APIs) and abnormalities on computed tomography angiography (CTA) that do not reflect true arterial injuries. We hypothesized that shorter intervals between tourniquet removal and CTA imaging and longer total tourniquet times would be correlated with a higher likelihood of false positive CTA.

MATERIALS AND METHODS

We performed a single-institution retrospective cohort study of patients presenting to a busy, urban Level 1 Trauma Center with prehospital tourniquets from 2019 to 2021. Patients who presented with a tourniquet disengaged upon arrival or who died prior to admission to the Trauma Unit were excluded. Tourniquet duration, time between tourniquet removal and CTA imaging (CTA interval), CTA findings, and management of extremity arterial injuries were extracted. The proportion of false positive injuries on CTA was assessed for correlation with increasing time interval from tourniquet removal to CTA imaging and correlation with increasing total tourniquet time using multivariable logistic regression.

RESULTS

251 patients were identified with prehospital tourniquets. 127 underwent CTA of the affected extremity, 96 patients had an abnormal CTA finding, and 57 (45% of total CTA patients) had false positive arterial injuries on imaging. Using multivariable logistic regression, neither the CTA interval nor the tourniquet duration was associated with false positive CTA injuries. Female sex was associated with false positive injuries on CTA (OR 2.91, 95% CI: 1.01 - 8.39). Vasospasm was cited as a possible explanation by radiologists in 40% of false positive CTA reports.

CONCLUSIONS

Arterial vasospasm is a frequent finding on CTA after tourniquet use for extremity trauma, but concerns regarding tourniquet-related vasospasm should not alter trauma patient management. Neither the duration of tourniquet application nor the time interval since removal is associated with decreased CTA accuracy, and any delay in imaging does not appear to reduce the likelihood of vasospasm. These findings are important for supporting expedited care of trauma patients with severe extremity injuries.

Association between impaired dynamic cerebral autoregulation and BBB disruption in reversible cerebral vasoconstriction syndrome

BACKGROUND

Half of the sufferers of reversible cerebral vasoconstriction syndrome (RCVS) exhibit imaging-proven blood-brain barrier disruption. The pathogenesis of blood-brain barrier disruption in RCVS remains unclear and mechanism-specific intervention is lacking. We speculated that cerebrovascular dysregulation might be associated with blood-brain barrier disruption in RCVS. Hence, we aimed to evaluate whether the dynamic cerebral autoregulation is altered in patients with RCVS and could be associated with blood-brain barrier disruption.

METHODS

A cross-sectional study was conducted from 2019 to 2021 at headache clinics of a national tertiary medical center. Dynamic cerebral autoregulation was evaluated in all participants. The capacity of the dynamic cerebral autoregulation to damp the systemic hemodynamic changes, i.e., phase shift and gain between the cerebral blood flow and blood pressure waveforms in the very-low- and low-frequency bands were calculated by transfer function analysis. The mean flow correlation index was also calculated. Patients with RCVS received 3-dimensional isotropic contrast-enhanced T2 fluid-attenuated inversion recovery imaging to visualize blood-brain barrier disruption.

RESULTS

Forty-five patients with RCVS (41.9 ± 9.8 years old, 29 females) and 45 matched healthy controls (41.4 ± 12.5 years old, 29 females) completed the study. Nineteen of the patients had blood-brain barrier disruption. Compared to healthy controls, patients with RCVS had poorer dynamic cerebral autoregulation, indicated by higher gain in very-low-frequency band (left: 1.6 ± 0.7, p = 0.001; right: 1.5 ± 0.7, p = 0.003; healthy controls: 1.1 ± 0.4) and higher mean flow correlation index (left: 0.39 ± 0.20, p = 0.040; right: 0.40 ± 0.18, p = 0.017; healthy controls: 0.31 ± 0.17). Moreover, patients with RCVS with blood-brain barrier disruption had worse dynamic cerebral autoregulation, as compared to those without blood-brain barrier disruption, by having less phase shift in very-low- and low-frequency bands, and higher mean flow correlation index.

CONCLUSIONS

Dysfunctional dynamic cerebral autoregulation was observed in patients with RCVS, particularly in those with blood-brain barrier disruption. These findings suggest that impaired cerebral autoregulation plays a pivotal role in RCVS pathophysiology and may be relevant to complications associated with blood-brain barrier disruption by impaired capacity of maintaining stable cerebral blood flow under fluctuating blood pressure.

Impact of ventriculo-cisternal irrigation on prevention of delayed cerebral infarction in aneurysmal subarachnoid hemorrhage: a single-center retrospective study and literature review

OBJECTIVE

The aim of this study was to evaluate the effectiveness of ventriculo-cisternal irrigation (VCI) in preventing vasospasms and delayed cerebral infarction (DCI) by washing out subarachnoid clots earlier after aneurysm surgery.

METHODS

We retrospectively identified 340 subarachnoid hemorrhage (SAH) patients with ruptured intracranial aneurysms treated with postoperative VCI at our institution between December 2010 and January 2020. As VCI therapy, a ventricular drain/cisternal drain was placed during aneurysm surgery, and lactated Ringer's solution was used for irrigation until day 4 of SAH, followed by intracranial pressure control at 5-10 cmH2O until day 14.

RESULTS

The median age was 65 years (interquartile range 52-75), with 236 female patients (69%). The World Federation of Neurosurgical Societies grade distribution was as follows: grade I or II, 175 patients (51%); grade III or IV, 84 (25%); and grade V, 81 (24%). With VCI management in all patients, total vasospasm occurred in 162 patients (48%), although the DCI incidence was low (23 patients [6.8%]). Major drainage-related complications were observed in five patients (1.5%). Early surgery, performed on SAH day 0 or 1, was identified as a preventive factor against DCI occurrence (odds ratio (OR) 0.21, 95% confidence interval (CI) 0.07-0.67; P = 0.008), while additional surgery (4.76, 1.62-13.98; P = 0.005) and dyslipidemia (3.27, 1.24-8.63; P = 0.017) were associated with DCI occurrence.

CONCLUSION

Managing vasospasms with VCI after SAH is considered a safe and effective method to prevent DCI. Early surgery after SAH may be associated with a decreased risk of DCI with VCI therapy.

Intra-arterial lipo-prostaglandin E1 infusion for arterial spasm in liver transplantation: A case report

BACKGROUND

Hepatic artery obstruction is a critical consideration in graft outcomes after living donor liver transplantation. We report a case of diffuse arterial vasospasm that developed immediately after anastomosis and was managed with an intra-arterial infusion of lipo-prostaglandin E1 (PGE1).

CASE SUMMARY

A 57-year-old male with hepatitis B virus-related liver cirrhosis and hepatocellular carcinoma underwent ABO-incompatible living donor liver transplant. The grafted hepatic artery was first anastomosed to the recipient's right hepatic artery stump. However, the arterial pulse immediately weakened. Although a new anastomosis was performed using the right gastroepiploic artery, the patient's arterial pulse rate remained poor. We attempted angiographic intervention immediately after the operation; it showed diffuse arterial vasospasms like 'beads on a string'. We attempted continuous infusion of lipo-PGE1 overnight via an intra-arterial catheter. The next day, arterial flow improved without any spasms or strictures. The patient had no additional arterial complications or related sequelae at the time of writing, 1-year post-liver transplantation.

CONCLUSION

Angiographic evaluation is helpful in cases of repetitive arterial obstruction, and intra-arterial infusion of lipo-PGE1 may be effective in treating diffuse arterial spasms.

What are the predictors of delayed cerebral ischaemia (DCI) after aneurysmal subarachnoid haemorrhage? An up-to-date systematic review

PURPOSE

Delayed Cerebral Ischaemia (DCI) remains an important preventable driver of poor outcome in aneurysmal subarachnoid haemorrhage (aSAH). Our ability to predict DCI is based on historical patient cohorts, which use inconsistent definitions for DCI. In 2010, a definition of DCI was agreed upon and published by a group of aSAH experts. The aim of this study was to identify predictors using this agreed definition of DCI.

METHODS

We conducted a literature search of Medline (PubMed) to identify articles published since the publication of the 2010 consensus definition. Risk factors and prediction models for DCI were included if they: (1) adjusted for confounding factors or were derived from randomised trials, (2) were derived from prospectively collected data and (3) included adults with aSAH. The strength of studies was assessed based on quality, risk of bias and applicability of studies using PROBAST.

RESULTS

Eight studies totalling 4,542 patients were included from 105 relevant articles from 4,982 records. The most common reason for not including studies was failure to use the consensus definition of DCI (75%). No prediction models were identified in the eligible studies. Significant risk factors for DCI included the presence of onsite neuro-interventional services, high Neuropeptide Y, admission leucocytosis, neutrophil:lymphocyte >5.9 and Fisher Grade > 2. All studies had a high or unclear risk of bias.

CONCLUSIONS

Only a few studies with high risk of bias have investigated the predictors using consensus-defined DCI. Further studies are warranted to clarify risk factors of DCI in the modern era.

Massive traumatic subarachnoid hemorrhage mimicking aneurysmal subarachnoid hemorrhage

Introduction

Massive traumatic subarachnoid hemorrhage (tSAH) is a rare but potentially life-threatening condition that can mimic the clinical presentation of aneurysmal subarachnoid hemorrhage (aSAH). The accurate differentiation between these two entities is crucial, as their management and prognoses significantly differ.

Case presentation

We present a case of a 64-year-old male patient who presented to our emergency department after being involved in a motor vehicle collision. His radiological findings on a computed tomography (CT) scan were suggestive of aSAH based on its location, which showed massive SAH in bilateral sylvian fissures and the basal cisterns. There was no evidence of vasospasm. The patient later developed a stroke despite the use of Nimodipine.

Conclusion

While traumatic subarachnoid hemorrhage mimicking aneurysmal subarachnoid hemorrhage is a recognized phenomenon, it is relatively uncommon. We present a case of massive tSAH complicated by a stroke with no evidence of aneurysm on cerebral angiogram, shedding light on the diagnostic challenges in differentiating tSAH from aSAH and emphasizing the importance of accurate diagnosis for appropriate management, in addition, we aim to remind the readers that trauma may be a cause for massive SAH and should prompt a medical SAH management plan.

Assessment of Residual Vasospasm in Patients with Plaque Rupture or Plaque Erosion using Optical Coherence Tomography

AIMS

Coronary vasospasm is associated with acute coronary syndrome (ACS) and may persist during primary percutaneous coronary intervention (PCI). We aimed to elucidate the incidence, morphological characteristics, and prognostic impact of residual vasospasm in plaque rupture (PR) and plaque erosion (PE) lesions using optical coherence tomography (OCT).

METHODS

We enrolled 142 patients with ACS who underwent OCT-guided primary PCI. All patients received intracoronary vasodilators before OCT examination. Residual vasospasm was identified as intimal gathering and categorised as polygonal- or wavy- patterned depending on the luminal shape. A wavy pattern was defined as a curved intimal surface line. A polygonal pattern was defined as a lumen with multiple angles. The incidence of major cardiovascular events, defined as death, non-fatal myocardial infarction, stroke, and any revascularization, within 1-year of PCI was identified.

RESULTS

The prevalence of residual vasospasm in PR and PE was 15.1% (13 of 86) and 21.4% (12 of 56), respectively. Wavy pattern was the major shape of the residual vasospasm. Polygonal-patterned lumen was more frequently observed in PR than in PE (38.5 vs. 8.3 %). The polygonal-patterned lumens had significantly larger lipid arcs (257.9 vs. 78.0 °; P＜0.01), and significantly smaller areas (1.27 vs. 1.88 mm2; P=0.05) than wavy patterned lumens. Residual vasospasm had a prognostic impact on PR but not PE at 1-year of successful primary PCI.

CONCLUSION

Considerable proportion of ACS including both PR and PE had residual vasospasm with variable morphological feature and different prognostic impact.

Outcome analysis for patients with subarachnoid hemorrhage and vasospasm including endovascular treatment

As a complication of subarachnoid hemorrhage (SAH), vasospasm substantially contributes to its morbidity and mortality. We aimed at analyzing predictors of outcome for these patients including the role of endovascular treatment (ET). Our database was screened for patients with SAH treated in our Neuro-ICU from 2009 to 2019. Clinical parameters including functional outcome (modified Rankin Scale, mRS of 0-2 or 3-6 at discharge and after a median follow-up of 18 months) and details about ET were gathered on 465 patients, 241 (52%) of whom experienced vasospasm. Descriptive analyses were performed to identify explanatory variables for the dichotomized mRS score. A logistic regression model was fitted on 241 patients with vasospasm including age, Hunt and Hess Score, extraventricular drainage (EVD), forced hypertension, ET and delayed cerebral ischemia (DCI). The model found a Hunt and Hess Score of 5 (OR = 0.043, p = 0.008), requirement of EVD (OR = 0.161, p < 0.001), forced hypertension (OR = 0.242, p = 0.001), ET (OR = 0.431, p = 0.043) and DCI (OR = 0.229, p < 0.001) to be negative predictors of outcome while age was not. Use of intraarterial nimodipine alone (OR = 0.778, p = 0.705) or including balloon angioplasty (OR = 0.894, p = 0.902) and number of ETs per patient (OR = 0.757, p = 0.416) were not significant in a separate model with otherwise identical variables. While DCI is clearly associated with poor outcome, the influence of ET on outcome remains inconclusive. Limited by their retrospective nature and an indication bias, these data encourage a randomized assessment of ET.

The impact of pre-ictal statin use on vasospasm and outcome in aneurysmal subarachnoid hemorrhage

BACKGROUND

Pleiotropic effects of statins may be beneficial in alleviating cerebral vasospasm (VS) and improving outcome after aneurysmal subarachnoid hemorrhage (aSAH). Initiation of statin treatment at aSAH is not recommended; however, the effect of pre-ictal and continued statin use is not fully investigated.

METHODS

Retrospective study comparing aSAH patients admitted in 2012 to 2021 with pre-ictal statin use versus those not using statins. Patient entry variables, radiological/sonological VS, symptomatic VS, and radiologically documented delayed cerebral ischemia (DCI) were registered. Outcome was scored in terms of mortality, modified Rankin score, Glasgow outcome score extended, and levels of fatigue. Patients were compared on group level and in a case-control design.

RESULTS

We included 961 patients, with 204 (21.2%) statin users. Statin users were older and had more often hypertension. Severe radiological/sonological VS, symptomatic VS, and DCI were less frequent in statin users, and their length of stay was shorter. Mortality, functional outcome, and levels of fatigue were similar in both groups. When analyzing 89 pairs of statin users and non-statin users matched for age, aSAH severity, gender, and hypertension, we confirmed decreased radiological/sonological and symptomatic VS as well as shorter length of stay in statin users. They also had more often a favorable functional outcome and lower levels of fatigue.

CONCLUSIONS

Patients with pre-ictal and continued use of statins have a reduced occurrence of radiological/sonological and symptomatic VS, shorter length of stay, and more often favorable functional outcome, whereas mortality is similar to non-statin users. Even though larger multicenter studies with common, strict protocols for prevention, diagnosis, and treatment of vasospasm are needed to finally establish the value of statins in aSAH, continuation of pre-ictal statin use seems worthwhile.

Brain damage evaluation via arterial spin labeling perfusion imaging for patients with aneurysmal subarachnoid hemorrhage

OBJECTIVE

Subarachnoid hemorrhage (SAH) is a neurological condition with an annual incidence of 6-22 per 100,000. Despite many advances in diagnosis, the rates of mortality and morbidity in patients remain high. The most important reason for this is complications accompanied by perfusion changes. The aim of our study was to show the perfusion changes with arterial spin labelling (ASL) after SAH.

MATERIALS AND METHODS

In this prospective study, 23 patients diagnosed with aneurysmal SAH were evaluated by ASL perfusion imaging between days 1-3 and 8-10. The mean signal intensities (SI) of both hemispheres from the anterior cerebral artery, middle cerebral artery, and basal ganglia were measured manually according to the region of interest. The relationship between the SI values calculated for both cerebral hemispheres, complications, and grading scales of the side with more intense (ipsilateral) and less (contralateral) bleeding were evaluated.

RESULTS

There was a significant difference in the ipsilateral/contralateral SI ratio (SIIps/ConBGin) (p = 0.015) among all ASL values, including the basal ganglia between days 0-3 and 8-10. There was a significant negative correlation between ASL parameters and rating scale scores. Additionally, when the SIIps/ConBGinDay0-3 ratio cut-off value was ≤ 0.72, the sensitivity and specificity were 57.1% and 100.0%, respectively, in predicting non-fatal complications, and the sensitivity and specificity in predicting all complications, including death, were 55.6% and 100.0%, respectively.

CONCLUSION

Global or regional perfusion decrease can be shown using ASL, with or without the development of vasospasm, without the need for exogenous contrast agent use.

Loss of Consciousness in a 34 Yo Male Related to Marijuana

Nontraumatic exertional syncope can be an ominous event reflecting profound arterial hypotension, cerebral hypoperfusion, and transient loss-of consciousness that occurs most commonly in patients with underlying cardiovascular disease. In contradistinction, transient loss-of-consciousness in "healthy adults" is typically vasovagal syncope related to exaggerated orthostatic cardiovascular responses attributed to a hyper-reactive autonomic nervous system. In the present report, a 34 yo male presents to the hospital emergency department (ED) for a sudden loss of consciousness and fall ultimately related to cardiac syncope ascribed to chronic recreational marijuana use complicated by coronary vasospasm.

The clinical course and outcomes of non-aneurysmal subarachnoid hemorrhages in a single-center retrospective study

BACKGROUND

Non-aneurysmal subarachnoid hemorrhages (SAHs) are thought to have a benign clinical course compared to aneurysmal SAHs. The aim of this study is to report the clinical course and outcomes of non-aneurysmal SAHs in a large single-center study.

METHODS

The patients with non-aneurysmal SAHs were screened from Tampere University Hospital from 2005 to 2020. The clinical data were collected from the patient's medical records and from the imaging studies. The primary interest was the neurological outcome assessed by dichotomized GOS at 2 months. Multivariable logistic regression was used to study the factors associated with unfavorable outcome.

RESULTS

We found 216 non-aneurysmal SAHs in 214 patients (2 patients with > 1 bleed). Ninety-seven percent of patients with a typical perimesencephalic bleeding pattern SAH (PSAH) (75/77) had a favorable outcome, while 86% of patients with non-perimesencephalic SAH (NPSAH) had a favorable outcome (84/98). In a multivariable logistic regression analysis, loss of consciousness (LOC) (aOR 214.67, 95% CI 17.62-2615.89) and Fisher grade 4 bleeding pattern (aOR 23.32, 95% CI 1.40-387.98) were associated with increased risk for unfavorable outcome (GOS 1-3). Vasospasm was seen in 20% of non-aneurysmal SAH patients, hydrocephalus in 17%, and 13% needed ventriculostomy.

CONCLUSIONS

Non-aneurysmal SAH seems to have a good prognosis for majority of patients, especially for patients with a PSAH. Non-aneurysmal SAH patients are however affected by vasospasm and hydrocephalus and have similar risk factors for poor outcome as patients with aneurysmal SAH. This suggests that it is the severity of the bleed rather than the etiology that associates with poor outcome.

Serum concentration-guided intravenous magnesium sulfate administration for neuroprotection in patients with aneurysmal subarachnoid hemorrhage: a retrospective evaluation of a 12-year single-center experience

Delayed cerebral infarction (DCI) is a major cause of morbidity and mortality in patients with aneurysmal subarachnoid hemorrhage (aSAH). The benefits of magnesium sulfate as an alternative treatment are controversial, and most previous studies examined its benefits only as adjunctive treatment to traditional nimodipine. We retrospectively analyzed aSAH patients records with magnesium sulfate between 2010 and 2021. We aimed for a serum magnesium concentration of 2-2.5 mmol/l between post-hemorrhage days 3 and 12. The patients were separated in three groups based on average serum magnesium concentration (magnesium >2 mmol/l, reduced magnesium 1.1-1.9 mmol/l, and no magnesium). Additionally, we assessed delayed cerebral infarction (DCI) and clinical outcome at follow-up, using the modified Rankin Scale (mRS), categorized in favorable (0-3) and unfavorable outcome (4-5). In this analysis, 548 patients were included. Hereof, radiological evidence of DCI could be found in 23.0% (n = 126) of patients. DCI rates were lower if patients' average serum magnesium was higher than 2 mmol/l (magnesium 18.8%, n = 85; reduced magnesium 38.3%, n = 23; no magnesium 51.4%, n = 18; p < 0.001). Also, at the last follow-up, patients in the group with a higher serum magnesium concentration had better outcome (favorable outcome: magnesium 64.7%, n = 293; reduced magnesium 50.0%, n = 30; no magnesium 34.3%, n = 12; p < 0.001). This 12-year study reveals the value of serum concentration-guided magnesium administration in aSAH patients. Our findings demonstrate the safety and efficacy when titrated to a serum concentration of 2-2.5 mmol/l. We observed higher rates of delayed cerebral infarction and unfavorable outcomes in patients with serum concentrations below 2 mmol/l.

Early recanalization and vasospasm after endovascular treatment in a case of ruptured vertebral artery dissecting aneurysm associated with COVID-19

Background

The coronavirus disease 2019 (COVID-19) pandemic has caused significant structural changes in acute care hospitals. COVID-19-associated stroke has gained attention, with abnormal coagulation and vascular endothelial damage being recognized. While ischemic cases are commonly reported, hemorrhagic cases have also been reported. This report presents a case of ruptured vertebral artery dissection aneurysm associated with COVID-19, resulting in subarachnoid hemorrhage (SAH). The treatment course, challenges in managing cerebral vasospasm, and early recanalization achieved through endovascular therapy are described.

Case Description

A 67-year-old male patient was brought to our hospital for emergency treatment of impaired consciousness that occurred while recovering from COVID-19. He underwent endovascular internal trapping using coils, and although the rupture did not recur, he required long-term tracheal management, which resulted in a cerebral infarction caused by cerebral vasospasm. In addition, early recanalization was seen, which required retreatment.

Conclusion

This case highlights the challenges in managing COVID-19-associated SAH and emphasizes the need for infection control measures and proper postoperative care. Establishing protocols for detecting and managing cerebral vasospasm is essential.

Antiplatelet therapy in aneurysmal subarachnoid hemorrhage: an updated meta-analysis

Antiplatelet therapy (AT) may serve to reduce the effects of aneurysmal subarachnoid hemorrhage (aSAH)-induced pro-coagulant state in the cerebral circulation. Several studies, however, have delivered conflicting conclusions on the efficacy of AT post aSAH. Systematic searches of Medline, Embase, and Cochrane Central were undertaken on 27th March 2023. The primary outcome was delayed cerebral ischaemia (DCI). Secondary outcomes were symptomatic and angiographic vasospasm, good functional outcome (modified Rankin Scale [mRS] with scores 0-2), hemorrhagic events, and in-hospital mortality. Twenty-two studies reporting 4378 patients with aSAH were included in the meta-analysis. AT was associated with lower rates of DCI (RR=0.62, 95% CI: 0.43; 0.89), symptomatic vasospasm (RR=0.63, 95% CI: 0.46; 0.86), and moderate/severe angiographic vasospasm (RR=0.74, 95% CI: 0.65; 0.84), with no effect on hemorrhagic complications (RR=1.36, 95% CI: 0.77; 2.41). When analyzing only post-ictal use of AT, AT additionally favored rates of good functional outcomes (RR=1.18, 95% CI: 1.10; 1.26) and in-hospital mortality (RR=0.56, 95% CI: 0.39; 0.80). In the subgroup treated with cilostazol, AT was associated with lower rates of DCI (RR=0.40, 95% CI: 0.32), symptomatic vasospasm (RR=0.47, 95% CI: 0.33; 0.65), moderate/severe angiographic vasospasm (RR=0.75, 95% CI: 0.57; 0.98) and good functional outcome (RR=1.24, 95% CI: 1.08; 1.43). In the surgically treated aSAH subgroup, AT favored rates of symptomatic vasospasm (RR=0.55, 95% CI: 0.30; 0.98), moderate/severe angiographic vasospasm (RR=0.70, 95% CI: 0.54; 0.90) and good functional outcome (RR=1.23, 95% CI: 1.09; 1.41). In the endovascularly treated aSAH subgroup, AT was associated with lower rates of in-hospital mortality (RR=0.60, 95% CI: 0.41; 0.88). In aSAH patients, post-ictal AT is associated with benefits in terms of rates of DCI, vasospasm, good functional outcomes, and in-hospital mortality without an increased risk of hemorrhagic events.

Vasodilatory effects of tadalafil in an animal model of cerebral vasospasm: Comparative analysis with oral nimodipine

OBJECTIVES

Cerebral vasospasm is one of the most fatal complications after spontaneous aneurysmal subarachnoid hemorrhage. Although various treatments have been tried for the treatment of cerebral vasospasm so far, the effect is insignificant or temporary except for oral nimodipine. Phosphodiesterase isozyme type 5 inhibitor, which is used to treat erection dysfunction, recently has been known to have a cerebrovascular vasodilation. It is thought that this will be effective in cerebral vasospasm, and the effect will be compared and analyzed with oral nimodipine through an animal model of cerebral vasospasm.

MATERIAL AND METHODS

A total of 40 rabbits were used to make subarachnoid hemorrhage model and were divided into three groups - a control group, nimodipine group, and tadalafil group. The cerebral vessels were angiographically measured before and on the third day of subarachnoid hemorrhage. Then vertebrobasilar arteries were harvested and evaluated. Under the microscope, lumen area and media area were measured for each group and were compared.

RESULTS

Angiographically, tadalafil group showed significant vasodilation compared with the control group (p < 0.01). Histologically, tadalafil showed a similar effect on lumen and on media area to that of nimodipine group compared with the control group.

CONCLUSIONS

Cerebral vasospasm could leave neurologic deficit or sequelae even after proper treatment. Therefore, prevention is important. Tadalafil showed preventive effect against cerebral vasospasm and vasodilative effect similar to that of nimodipine. Therefore, tadalafil could be considered an alternative preventive treatment of cerebral vasospasm.

The impact of collateral status on cerebral vasospasm and delayed cerebral ischemia in subarachnoid hemorrhage

OBJECTIVE

Cerebral collateral circulation may affect subarachnoid hemorrhage (SAH) induced cerebral vasospasm and delayed cerebral ischemia. In this study our aim was to investigate the relationship between collateral status, vasospasm and delayed cerebral ischemia (DCI) in both aneurysmal and nonaneurysmal SAH.

METHODS

Patients diagnosed as SAH with and without aneurysm were included and their data investigated retrospectively. After the patients diagnosed as SAH according to cerebral computed tomography (CT)/magnetic resonance imaging (MRI), they underwent cerebral angiography to check for cerebral aneurysm. The diagnosis of DCI was made according to the neurological examination and control CT/MRI. All the patients had their control cerebral angiography on days 7 to 10 in order to assess vasospasm and also collateral circulation. The American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN/SIR) Collateral Flow Grading System was modified to measure collateral circulation.

RESULTS

A total of 59 patients data were analyzed. Patients with aneurysmal SAH had higher Fisher scores and DCI was more common. Although there was no statistically significant difference between the patients with and without DCI in terms of demographics and mortality, patients with DCI had worse collateral circulation and more severe vasospasm. These patients had higher Fisher scores and more cerebral aneurysm overall.

CONCLUSIONS

According to our data, patients with higher Fisher scores, more severe vasospasm, and poor cerebral collateral circulation may experience DCI more frequently. Additionally aneurysmal SAH had higher Fisher scores and DCI was seen more common. To improve the clinical results for SAH patients, we believe that physicians should be aware of the DCI risk factors.

Cold Hands or Feet: Is It Raynaud's or Not?

Raynaud's phenomenon is an exaggerated response to cold stimuli that may be primary or secondary. The diagnosis relies on patient history and physical examination to distinguish RP from other vasomotor dysfunction (e.g. acrocyanosis, pernio, small fiber neuropathy with vasomotor symptoms, and complex regional pain syndrome). Achenbach syndrome, or spontaneous venous hemorrhage, may also be mistaken for RP but is a self-limiting phenomenon. Laboratory evaluation and vascular diagnostic testing may identify SRP causes. Regardless of etiology, treatment includes warming with trigger avoidance, and consideration of vasodilators (eg. calcium channel, alpha-1 blockers). SRP with digital ulceration may require PDE5i, endothelin-1 receptor blockers, and prostanoids. Refractory cases may require pneumatic arterial pumps, botulinum toxin administration, or surgical sympathectomy.

Real-world data of clazosentan in combination therapy for aneurysmal subarachnoid hemorrhage: a multicenter retrospective cohort study

Aneurysmal subarachnoid hemorrhage (aSAH) may lead to cerebral vasospasm, significantly associated with morbidity and mortality. In double-blind, placebo-controlled phase 3 studies, clazosentan reduces cerebral vasospasm-related morbidity and all-cause mortality in patients with aSAH. There are no reports about the clinical efficacy of clazosentan combination therapy with some other drugs. Initially, we explored the efficacy of clazosentan combination therapy with cilostazol, statin, and antiepileptic drugs. Subsequently, we assessed the add-on effect of fasudil to clazosentan combination therapy for aSAH patients. This multicenter, retrospective, observational cohort study included Japanese patients with aSAH between June 2022 and March 2023. The primary outcome was the ordinal score on the modified Rankin Scale (mRS; range, 0-6, with elevated scores indicating greater disability) at discharge. Among the 47 cases (women 74.5%; age 64.4 ± 15.0 years) undergoing clazosentan combination therapy, 29 (61.7%) resulted in favorable outcomes. Overall, vasospasm occurred in 16 cases (34.0%), with four cases (8.5%) developing vasospasm-related delayed cerebral ischemia (DCI). Both hypotension and vasospasm-related DCI were related to unfavorable outcome at discharge. Fasudil were added in 18 (38.3%) cases. Despite adding fasudil to clazosentan combination therapy, the incidence of aSAH-related vasospasm did not decrease. Added-on fasudil to combination therapy related to pulmonary edema, vasospasm, and vasospasm-related DCI, and unfavorable outcomes. Clazosentan combination therapy could potentially result in favorable outcomes for aSAH patients to prevent post-aSAH vasospasm-related DCI. The add-on effect of fasudil to combination therapy did not demonstrate a significant impact in reducing aSAH-related vasospasm or improving outcomes at discharge.

Practical Approach for Angina and Non-Obstructive Coronary Arteries: A State-of-the-Art Review

Anginal symptoms are frequently encountered in patients without the presence of significant obstructive coronary artery disease (CAD). It is increasingly recognized that vasomotor disorders, such as an abnormal vasodilatory capacity of the coronary microcirculation or coronary vasospasm, are the dominant pathophysiological substrate in these patients. Although the evidence with respect to angina in patients with non-obstructive coronary arteries is accumulating, the diagnosis and treatment of these patients remains challenging. In this review, we aimed to provide a comprehensive overview regarding the pathophysiological origins of angina with non-obstructive coronary arteries disorders and its diagnostic and therapeutic considerations. Hereby, we provide a practical approach for the management of patents with angina and non-obstructive CAD.

Neurological Pupil Index and Delayed Cerebral Ischemia after Subarachnoid Hemorrhage: A Retrospective Multicentric Study

BACKGROUND

Delayed cerebral ischemia (DCI) occurs in around 30% of patients suffering from nontraumatic subarachnoid hemorrhage (SAH) and is associated with poor neurological outcome. Whether the Neurological Pupil index (NPi) derived from the automated pupillometry could help to diagnose the occurrence of DCI remains unknown. The aim of this study was to investigate the association of NPi with the occurrence of DCI in patients with SAH.

METHODS

This was a multicenter, retrospective cohort study of consecutive patients with SAH admitted to the intensive care units of five hospitals between January 2018 and December 2020 who underwent daily NPi recordings (every 8 h) during the first 10 days of admission. DCI was diagnosed according to standard definitions (in awake patients) or based on neuroimaging and neuromonitoring (in sedated or unconscious patients). An NPi < 3 was defined as abnormal. The primary outcome of the study was to assess the time course of daily NPi between patients with DCI and patients without DCI. Secondary outcome included the number of patients who had an NPi < 3 before DCI.

RESULTS

A total of 210 patients were eligible for the final analysis; DCI occurred in 85 (41%) patients. Patients who developed DCI had similar values of mean and worst daily NPi over time when compared with patients without DCI. Patients with DCI had a higher proportion of at least one NPi < 3 at any moment before DCI when compared with others (39/85, 46% vs. 35/125, 38%, p = 0.009). Similarly, the worst NPi before DCI diagnosis was lower in the DCI group when compared with others (3.1 [2.5-3.8] vs. 3.7 [2.7-4.1], p = 0.05). In the multivariable logistic regression analysis, the presence of NPi < 3 was not independently associated with the development of DCI (odds ratio 1.52 [95% confidence interval 0.80-2.88]).

CONCLUSIONS

In this study, NPi measured three times a day and derived from the automated pupillometry had a limited value for the diagnosis of DCI in patients with SAH.

Paediatric subarachnoid haemorrhage and severe vasospasm secondary to traumatic pseudoaneurysm of a fenestrated vertebral artery: a case report and review of the literature

Paediatric intracranial aneurysms are rare entities accounting for less than 5% of all age intracranial aneurysms. Traumatic aneurysms are more common in children and have an association with anatomical variations such as arterial fenestrations. Here, we present a case of a child initially presenting with traumatic subarachnoid haemorrhage who returned to baseline and was discharged home only to return within 2 weeks with diffuse subarachnoid and intraventricular re-haemorrhage. A dissecting aneurysm of a duplicated (fenestrated) V4 vertebral artery segment was identified as a rare cause of rebleeding. We describe a course complicated by severe vasospasm delaying aneurysm detection and treatment. Dissecting aneurysms in children should be considered in all cases of delayed post-traumatic cranial rebleeding, particularly where there is anomalous arterial anatomy.

Progressive arteriopathy with vasospasm in focal cerebral arteriopathy in childhood: a case report

BACKGROUND

Focal cerebral arteriopathy (FCA) is a clinically important disease that often causes progressive arteriopathy. We report a case of FCA with progressive arteriopathy due to arterial shrinkage of the outer diameter found on T2-weighted three-dimensional sampling perfection with application optimized contrasts using different flip angle evolutions (3D-SPACE) imaging.

CASE PRESENTATION

The patient was a 9-year-old girl who developed right hemiparesis. Acute infarction was detected in the basal ganglia. Vascular images revealed stenosis from the distal internal carotid artery (ICA) to the middle cerebral artery (MCA). Intravenous heparin was administered for 8 days, and the symptoms improved. However, 29 days after onset, right hemiparesis transiently developed again and magnetic resonance angiography (MRA) showed progressive stenosis from the ICA to MCA, while 3D-SPACE showed similar shrinkage of the outer diameter. Aspirin was started, and there was no subsequent recurrence. After 12 months, MRA and 3D-SPACE showed improvement of stenosis and arterial shrinkage.

CONCLUSIONS

Given the time course, the change in the outer diameter was thought to be vasospasm. Thus, vasospasm may be one of the causes of progressive arteriopathy in FCA.

Postoperative vasospasm and cerebral infarction in a patient with large pituitary adenoma and cerebral superficial siderosis

BACKGROUND

Cerebral vasospasm and infarction are rare complications of transsphenoidal surgery for pituitary adenoma. Cerebral superficial siderosis may result from subarachnoid hemorrhage from a pituitary adenoma. The constellation of cerebral superficial siderosis, cerebral vasospasm, and pituitary adenoma is rare. We describe an extremely rare clinical constellation of immediately postoperative cerebral vasospasm and consequent cerebral infarction in a case with a large pituitary adenoma and cerebral superficial siderosis.

CASE DESCRIPTION

A 70-year-old man presented with a pituitary adenoma causing a worsening headache. Preoperative magnetic resonance (MR) images revealed cerebral superficial siderosis, suggesting subarachnoid hemorrhage from pituitary apoplexy. MR angiography (MRA) showed no vasospasm. During the transsphenoidal surgery, an intratumoral hematoma was found. The arachnoid membrane was partially torn and intratumoral hematoma entered the subarachnoid space. Intraoperatively, the intracranial vessels remained intact. The suprasellar tumor was almost entirely resected; however, the patient remained comatose postoperatively. Computed tomography revealed ischemic lesions in the bilateral insular and frontotemporal cortex. MRA revealed cerebral vasospasm in the bilateral middle cerebral arteries. The patient was treated with levetiracetam for nonconvulsive status epilepticus and underwent a lumbar peritoneal shunt surgery for secondary hydrocephalus. However, the patient remained listless.

CONCLUSION

Postoperative cerebral vasospasm and infarction are severe but rare complications for a pituitary adenoma after transsphenoidal surgery. Preoperative and intraoperative subarachnoid hemorrhage might have been a risk factor in our case. Similar cases should be warranted to analyze whether cerebral superficial siderosis may also indicate the risk of severe postoperative vasospasm immediately after transsphenoidal surgery for pituitary adenoma.

Treatment of aneurysmal subarachnoid hemorrhage in subacute phase; retrospective comparison of treatment in sub- and hyper-acute phases

OBJECTIVE

As soon as possible treatment initiation for aneurysmal subarachnoid hemorrhage (aSAH) is recommended. However, some patients require treatment in "subacute" phase of aSAH, defined in this study as "more than one day after the onset". To establish an optimal treatment strategy for these patients, we retrospectively analyzed the clinical experience of treating ruptured aneurysm with either clipping or coiling in subacute phase.

METHODS

Patients treated for aSAH between 2015 and 2021were analyzed. Patients were divided into the hyperacute phase (within 24 h) and subacute phase (later than 24 h) groups. The subacute group was analyzed to determine whether the selected procedure and its timing affected postoperative course and clinical outcomes. In addition, we conducted a multivariate logistic regression analysis to determine the independent factors that affect clinical outcomes.

RESULTS

Of 215 patients, 31 were treated in the subacute phase. While cerebral vasospasm at initial imaging was more frequently observed in subacute group, there was no difference in incidence of postoperative vasospasms. Patients in subacute group seemed to have better clinical outcomes due to the milder severity at the time of treatment initiation. Risk of angiographic vasospasm seemed to be higher in patients treated with clipping than coiling, while no difference was seen in clinical outcomes. Multivariate logistic regression analysis showed that the timing and selected treatment did not significantly affect the clinical outcome or the occurrence of delayed vasospasm.

CONCLUSIONS

Treatment of aSAH in the subacute phase may also result in favorable clinical outcomes, similar to patients treated in the hyperacute phase with mild presentation. However, further investigations are required to establish the optimal treatment strategies for such patients.

Management of postoperative cerebral vasospasm in skull base surgeries: A systematic review of case reports and series

Background

This study provides a comprehensive overview of the management of postoperative vasospasm after skull base surgeries. This phenomenon is rare but can be of serious sequelae.

Methods

Medline, Embase, and PubMed Central were searched, along with examining the references of the included studies. Only case reports and series that reported vasospasm following a skull base pathology were incorporated. Cases with pathologies other than skull base, subarachnoid hemorrhage, aneurysm, and reversible cerebral vasoconstriction syndrome were excluded from the study. Quantitative data were presented as mean (Standard Deviation) or median (range), accordingly, while qualitative data were presented as frequency (percentage). Chi- square test and one-way analysis of variance were used to assess for any association between the different factors and patient outcomes.

Results

We had a total of 42 cases extracted from the literature. The mean age was 40.1 (±16.1) with approximately equal males and females (19 [45.2%] and 23 [54.8%], respectively). The time to develop vasospasm after the surgery was 7 days (±3.7). Most of the cases were diagnosed by either angiogram or magnetic resonance angiography. Seventeen of the 42 patients had pituitary adenoma as the pathology. Anterior circulation was nearly affected in all patients. For management, most patients received pharmacological with supportive management. Twenty-three patients had an incomplete recovery as a result of vasospasm.

Conclusion

Vasospasm following skull base operations can affect males and females, and most patients in this review were middle-aged adults. The outcome of patients varies; however, most patients did not achieve a full recovery. There was no correlation between any factors and the outcome.

Diluted intracisternal papaverine for microvascular protection of cranial nerves during vestibular schwannoma and cerebello-pontine angle surgery. Commentary and review of the literature

Vasospasm after resection of skull base tumors is a rare complication that often produces relevant ischemic sequelae. This review of the literature reports a number of published experiences that can help determine the potential causes of vasospasm after cerebello-pontine angle (CPA) tumor and -in particular-vestibular schwannoma (VS) resection, the ways to prevent it, and the methods to obtain the correct diagnosis. The cause appears to be multifactorial and the surgical approach may contribute to the pathogenesis of vasospasm. Neurosurgeons must pay attention to detect possible vasospasm at an early stage of cerebello-pontine. Cerebral blood flow measurement and transcranial Doppler are useful monitoring tools. Intra-operative prevention of vasospasm during CPA tumor resection with papaverine hydrochloride (PPV) seems to play a relevant role. In particular, PPV is a direct-acting vasodilator used to manage vasospasm during various neurosurgical operations. There is large uncertainty about intracisternal PPV dose-related efficacy and side effects. Dilution of PPV in saline prior to application is recommended to avoid complications. In our experience, in line with the literature, we use a pure PPV without excipients 60 mg/2 ml diluted in 20 cc of 0,9% saline solution (0,3%) to prevent Hearing Loss during Posterior Fossa Microvascular Decompression for Typical Trigeminal Neuralgia and other cranial nerves potentially involved during VS and other CPA tumor resection. The aim of this commentary is to analyze and discuss the role of diluted intracisternal PPV for microvascular protection of cranial nerves during CPA tumor surgery.

Impact of Early Out-of-Bed Mobilization on Functional Outcome in Patients with Aneurysmal Subarachnoid Hemorrhage: A Retrospective Cohort Study

BACKGROUND

Effects of early mobilization are not well documented in patients with aneurysmal subarachnoid hemorrhage (aSAH). Only a few studies have investigated it through progressive mobilization protocols and suggested that it is safe and feasible. This study aimed to determine the impact of early out-of-bed mobilization (EOM) on 3-month functional outcome and cerebral vasospasm (CVS) occurrence in patients with aSAH.

METHODS

A retrospective review of consecutive patients admitted to the intensive care unit with a diagnosis of aSAH was performed. EOM was defined as out-of-bed (OOB) mobilization performed before or on day 4 after aSAH onset. The primary outcome was 3-month functional independence (i.e., a modified Rankin Scale below 3) and the occurrence of CVS.

RESULTS

A total of 179 patients with aSAH met the inclusion criteria. Thirty-one patients constituted the EOM group, and 148 patients were in the delayed out-of-bed mobilization group. Functional independence was more frequent in the EOM group than in the delayed out-of-bed mobilization group (n = 26 [84%] vs. n = 83 [56%], P = 0.004). In a multivariable analysis, EOM was an independent predictor of functional independence (adjusted odds ratio = 3.11; 95% confidence interval, 1.11-10.36; P < 0.05). The delay between bleeding and first OOB mobilization was also identified as an independent risk factor for the occurrence of CVS (adjusted odds ratio = 1.12; 95% confidence interval = 1.06-1.18, P < 0.001).

CONCLUSIONS

EOM was independently associated with favorable functional outcome after aSAH. The delay between bleeding and OOB mobilization was an independent risk factor for reduced functional independence and CVS occurrence. Prospective randomized trials are necessary to confirm these results and improve clinical practice.

Posterior cerebral artery stenosis related to implanted intracranial electrodes for temporal lobe epilepsy: A case report

INTRODUCTION

Intracranial electroencephalography is a crucial diagnostic technique for epilepsy surgery, though it is associated with a range of complications, including infection, intracranial hemorrhage, increased intracranial pressure, and cerebral infarction. This case study presents an uncommon occurrence of stenosis of the left posterior cerebral artery (PCA) following intracranial electrode implantation.

CASE PRESENTATION

A woman in her thirties with drug-resistant focal impaired awareness seizures underwent implantation of subdural and depth electrodes on the bilateral temporal lobes to lateralize seizure onset. A left anterior-temporal lobectomy was performed based on the evaluation results. Following the resection of the hippocampus, stenosis of the left PCA, with a pinched appearance, was observed. Postoperatively, extensive cerebral edema in the bilateral temporal lobes and a defect in the left PCA were detected on magnetic resonance (MR) imaging. MR imaging performed the day after surgery showed cerebral infarction in the left medial temporal lobe and left lateral thalamus. A video review indicated that surgical manipulation was not the cause of vascular stenosis. MR angiography one week later confirmed the recanalization of the PCA.

DISCUSSION

We surmised that the subdural electrodes inserted along the middle skull base might have induced the PCA stenosis or spasms. The patient did not experience any significant sequelae, with no episodes of seizures for more than five years after surgery.

CONCLUSION

It is essential to note that subdural grid electrodes placed in the medial temporal lobe can cause vascular stenosis, albeit with an extremely rare occurrence.

The effects of aneurysmal subarachnoid hemorrhage on cerebral vessel diameter and flow velocity

BACKGROUND

Transcranial Doppler flow velocity is used to monitor for cerebral vasospasm following aneurysmal subarachnoid hemorrhage. Generally, blood flow velocities appear inversely related to the square of vessel diameter representing local fluid dynamics. However, studies of flow velocity-diameter relationships are few, and may identify vessels for which diameter changes are better correlated with Doppler velocity. We therefore studied a large retrospective cohort with concurrent transcranial Doppler velocities and angiographic vessel diameters.

METHODS

This is a single-site, retrospective, cohort study of adult patients with aneurysmal subarachnoid hemorrhage, approved by the UT Southwestern Medical Center Institutional Review Board. Study inclusion required transcranial Doppler measurements within </= 24 hours of vessel imaging. Vessels assessed were: bilateral anterior, middle, posterior cerebral arteries; internal carotid siphons; vertebral arteries; and basilar artery. Flow velocity-diameter relationships were constructed and fitted with a simple inverse power function. A greater influence of local fluid dynamics is suggested as power factors approach two.

RESULTS

98 patients were included. Velocity-diameter relationships are curvilinear, and well fit by a simple inverse power function. Middle cerebral arteries showed the highest power factors (>1.1, R²>0.9). Furthermore, velocity and diameter changed (P<0.033) consistent with the signature time course of cerebral vasospasm.

CONCLUSIONS

These results suggest that middle cerebral artery velocity-diameter relationships are most influenced by local fluid dynamics, which supports these vessels as preferred endpoints in Doppler detection of cerebral vasospasm. Other vessels showed less influence of local fluid dynamics, pointing to greater role of factors outside the local vessel segment in determining flow velocity.