Attributing hypodensities on CT to angiographic vasospasm is not sensitive and unreliable

Aneurysmal Subarachnoid Hemorrhage: the Last Decade

Aneurysmal subarachnoid hemorrhage (SAH) affects six to nine people per 100,000 per year, has a 35% mortality, and leaves many with lasting disabilities, often related to cognitive dysfunction. Clinical decision rules and more sensitive computed tomography (CT) have made the diagnosis of SAH easier, but physicians must maintain a high index of suspicion. The management of these patients is based on a limited number of randomized clinical trials (RCTs). Early repair of the ruptured aneurysm by endovascular coiling or neurosurgical clipping is essential, and coiling is superior to clipping in cases amenable to both treatments. Aneurysm repair prevents rebleeding, leaving the most important prognostic factors for outcome early brain injury from the hemorrhage, which is reflected in the neurologic condition of the patient, and delayed cerebral ischemia (DCI). Observational studies suggest outcomes are better when patients are managed in specialized neurologic intensive care units with inter- or multidisciplinary clinical groups. Medical management aims to minimize early brain injury, cerebral edema, hydrocephalus, increased intracranial pressure (ICP), and medical complications. Management then focuses on preventing, detecting, and treating DCI. Nimodipine is the only pharmacologic treatment that is approved for SAH in most countries, as no other intervention has demonstrated efficacy. In fact, much of SAH management is derived from studies in other patient populations. Therefore, further study of complications, including DCI and other medical complications, is needed to optimize outcomes for this fragile patient population.

Lessons from the CONSCIOUS-1 Study

After years of research on treatment of aneurysmal subarachnoid hemorrhage (aSAH), including randomized clinical trials, few treatments have been shown to be efficacious. Nevertheless, reductions in morbidity and mortality have occurred over the last decades. Reasons for the improved outcomes remain unclear. One randomized clinical trial that has been examined in detail with these questions in mind is Clazosentan to Overcome Neurological Ischemia and Infarction Occurring After Subarachnoid Hemorrhage (CONSCIOUS-1). This was a phase-2 trial testing the effect of clazosentan on angiographic vasospasm (aVSP) in patients with aSAH. Clazosentan decreased moderate to severe aVSP. There was no statistically significant effect on the extended Glasgow outcome score (GOS), although the study was not powered for this endpoint. Data from the approximately 400 patients in the study were detailed, rigorously collected and documented and were generously made available to one investigator. Post-hoc analyses were conducted which have expanded our knowledge of the management of aSAH. We review those analyses here.

Three-dimensional spin-echo-based black-blood MRA in the detection of vasospasm following subarachnoid hemorrhage

BACKGROUND

Black-blood MR angiography (BBMRA), which utilizes a non-T₁ contrast spin-echo type technique, has been expected to overcome several issues associated with time-of-flight (TOF) MRA.

PURPOSE

To investigate the efficacy of BBMRA to detect vasospasms following subarachnoid hemorrhage (SAH).

STUDY TYPE

Retrospective.

SUBJECTS

Seventeen patients with SAH in their early posttreatment period.

FIELD STRENGTH/SEQUENCE

BBMRA, which uses a volumetric isotropic turbo spin-echo acquisition (VISTA), and TOF-MRA on 1.5T scanners.

ASSESSMENT

Visualization of supratentorial arteries and veins in BBMRA was rated on a 4-point scale by two neuroradiologists. Another neuroradiologist independently assessed TOF-MRA. The degree of the vasospasm was then evaluated using a 3-point scale by the same readers. The diagnostic performance of the MRAs was evaluated using computed tomography angiography (CTA) or digital subtraction angiography (DSA) as the standard of reference.

STATISTICAL TESTS

Wilcoxon signed rank test, McNemar test, and Cohen's kappa coefficient.

RESULTS

BBMRA provided superior visualization of the anterior and middle cerebral arteries than TOF-MRA (P < 0.05). The depiction of the veins was more pronounced on BBMRA (P < 0.01). Of the 166 arterial segments evaluated by CTA or DSA, 23 (13.9%) could not be assessed using TOF-MRA because of high signal hemorrhage, whereas BBMRA enabled visualization of all the segments. Vasospasm was confirmed in 30 segments by CTA or DSA. The sensitivity, specificity, and positive and negative predictive values were 73, 96, 76, and 95 for TOF-MRA and 91, 100, 100, and 98 for BBMRA, respectively (P = 0.13 for sensitivity, P = 0.06 for specificity). The agreement of the degree of vasospasm between MRA and the standard of reference, as indicated by kappa value, was 0.71 (95% confidence interval [CI], 0.55-0.87) for TOF-MRA and 0.91 (95% CI, 0.82-0.99) for BBMRA.

DATA CONCLUSION

BBMRA, owing to its contrast properties, may be superior to TOF-MRA for the evaluation of intracranial arteries after SAH.

LEVEL OF EVIDENCE

3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;49:800-807.

Monitoring the Neuroinflammatory Response Following Acute Brain Injury

Traumatic brain injury (TBI) and subarachnoid hemorrhage (SAH) are major contributors to morbidity and mortality. Following the initial insult, patients may deteriorate due to secondary brain damage. The underlying molecular and cellular cascades incorporate components of the innate immune system. There are different approaches to assess and monitor cerebral inflammation in the neuro intensive care unit. The aim of this narrative review is to describe techniques to monitor inflammatory activity in patients with TBI and SAH in the acute setting. The analysis of pro- and anti-inflammatory cytokines in compartments of the central nervous system (CNS), including the cerebrospinal fluid and the extracellular fluid, represent the most common approaches to monitor surrogate markers of cerebral inflammatory activity. Each of these compartments has a distinct biology that reflects local processes and the cross-talk between systemic and CNS inflammation. Cytokines have been correlated to outcomes as well as ongoing, secondary injury progression. Alongside the dynamic, focal assay of humoral mediators, imaging, through positron emission tomography, can provide a global in vivo measurement of inflammatory cell activity, which reveals long-lasting processes following the initial injury. Compared to the innate immune system activated acutely after brain injury, the adaptive immune system is likely to play a greater role in the chronic phase as evidenced by T-cell-mediated autoreactivity toward brain-specific proteins. The most difficult aspect of assessing neuroinflammation is to determine whether the processes monitored are harmful or beneficial to the brain as accumulating data indicate a dual role for these inflammatory cascades following injury. In summary, the inflammatory component of the complex injury cascade following brain injury may be monitored using different modalities. Using a multimodal monitoring approach can potentially aid in the development of therapeutics targeting different aspects of the inflammatory cascade and improve the outcome following TBI and SAH.

Dissociation of Early and Delayed Cerebral Infarction After Aneurysmal Subarachnoid Hemorrhage

Background and Purpose—

Cerebral infarction after aneurysmal subarachnoid hemorrhage is a significant cause of substantial morbidity and mortality. Because early and delayed cerebral infarction after aneurysmal subarachnoid hemorrhage may be mediated by different processes, we evaluated whether aneurysm-securing methods contributed to infarcts and whether long-term outcomes differ between early and delayed infarcts.

Methods—

A post hoc analysis of the CONSCIOUS-1 study (Clazosentan to Overcome Neurological Ischemia and Infarction Occurring After Subarachnoid Hemorrhage) was performed. Using multivariate logistic regression analysis and propensity matching, independent clinical risk factors associated with infarctions were identified, and the contribution of cerebral infarcts to long-term outcomes was evaluated.

Results—

Within the cohort of 413 subjects, early infarcts were present in 76 subjects (18%), whereas delayed infarcts occurred in 79 subjects (19%), and 36 subjects (9%) had new infarctions that were present on both early and delayed imaging. Propensity score matching revealed a significantly higher proportion of early infarcts after clipping (odds ratio, 4.62; 95% confidence interval, 1.99–11.57; P =0.00012). Multivariate logistic regressions identified clipping as an independent risk factor for early cerebral infarction (odds ratio, 0.26; 95% confidence interval, 0.15–0.48; P <0.001), and angiographic vasospasm was an independent risk factor for delayed cerebral infarction (odds ratio, 1.79; 95% confidence interval, 1.03–3.13; P =0.039). Early infarcts were a significant independent risk factor for poor long-term outcomes at 3 months (odds ratio, 2.34; 95% confidence interval, 1.18–4.67; P =0.015).

Conclusions—

Clipping is an independent risk factor for the development of early cerebral infarcts, whereas delayed cerebral infarcts are associated with angiographic vasospasm. Early cerebral infarcts are stronger predictors of worse outcome than delayed infarction.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT00111085.

NEWTON: Nimodipine Microparticles to Enhance Recovery While Reducing Toxicity After Subarachnoid Hemorrhage

BACKGROUND

Aneurysmal subarachnoid hemorrhage (aSAH) is associated with high morbidity and mortality. EG-1962 is a sustained-release microparticle formulation of nimodipine that has shown preclinical efficacy when administered intraventricularly or intracisternally to dogs with SAH, without evidence of toxicity at doses in the anticipated therapeutic range. Thus, we propose to administer EG-1962 to humans in order to assess safety and tolerability and determine a dose to investigate efficacy in subsequent clinical studies.

METHODS

We describe a Phase 1/2a multicenter, controlled, randomized, open-label, dose escalation study to determine the maximum tolerated dose (MTD) and assess the safety and tolerability of EG-1962 in patients with aSAH. The study will comprise two parts: a dose escalation period (Part 1) to determine the MTD of EG-1962 and a treatment period (Part 2) to assess the safety and tolerability of the selected dose of EG-1962. Patients with a ruptured saccular aneurysm treated by neurosurgical clipping or endovascular coiling will be considered for enrollment. Patients will be randomized to receive either EG-1962 (study drug: nimodipine microparticles) or oral nimodipine in the approved dose regimen (active control) within 60 h of aSAH.

RESULTS

Primary objectives are to determine the MTD and the safety and tolerability of the selected dose of intraventricular EG-1962 as compared to enteral nimodipine. The secondary objective is to determine release and distribution by measuring plasma and CSF concentrations of nimodipine. Exploratory objectives are to determine the incidence of delayed cerebral infarction on computed tomography, clinical features of delayed cerebral ischemia, angiographic vasospasm, and incidence of rescue therapy and clinical outcome. Clinical outcome will be determined at 90 days after aSAH using the extended Glasgow outcome scale, modified Rankin scale, Montreal cognitive assessment, telephone interview of cognitive status, and Barthel index.

CONCLUSION

Here, we describe a Phase 1/2a multicenter, controlled, randomized, open-label, dose escalation study to determine the MTD and assess the safety and tolerability of EG-1962 in patients with aSAH.

The network topology of aneurysmal subarachnoid haemorrhage

OBJECTIVE

Network analysis is an emerging tool for the study of complex systems. In the current report, the cascade of physiological and neurological changes following aneurysmal subarachnoid haemorrhage (SAH) was modelled as a complex system of interacting parameters. Graph theoretical analysis was then applied to identify parameters at critical topological junctions of the network, which may represent the most effective therapeutic targets.

METHODS

Correlation matrices were calculated using a combination of Pearson, polyserial and polychoric regressions among 50 variables collected from 120 participants (38 male; mean age 51 years) included in the CONSCIOUS-1 trial. Graph theoretical analysis was performed to identify important topological features within the network formed by the interactions among these variables. Non-parametric resampling was applied to determine thresholds for significance.

RESULTS

Several critical network hubs were identified, including the incidence of delayed ischaemic neurological deficit (DIND), anaemia and hypoalbuminaemia/hypoproteinaemia. While not significant hubs, World Federation of Neurosurgical Societies (WFNS) score and use of rescue therapy had widespread connections within the network. Patient sex and history of hypertension also strongly clustered with other variables. A subnetwork (module) was also identified, which was related to neurological outcomes including WFNS score, angiographic vasospasm, DIND, use of rescue therapy and hydrocephalus.

INTERPRETATION

Using graph theoretical analysis, we identify critical network topologies following SAH, which may serve as useful therapeutic targets. Importantly, we demonstrate that network analysis is a robust method to model complex interactions following SAH.

TRIAL REGISTRATION NUMBER

URL: http://www.clinicaltrials.gov; Identifier: NCT00111085.

The effects of fluid balance and colloid administration on outcomes in patients with aneurysmal subarachnoid hemorrhage: a propensity score-matched analysis

BACKGROUND

Delayed ischemic neurological deficit (DIND) following aneurysmal subarachnoid hemorrhage (SAH) remains a significant cause of mortality and disability. The administration of colloids and the induction of a positive fluid balance during the vasospasm risk period remain controversial. Here, we compared DIND and outcomes among propensity score-matched cohorts who did and did not receive colloids and also tested the effect of a positive fluid balance on these endpoints.

METHODS

Exploratory analysis was performed on 413 patients enrolled in CONSCIOUS-1, a prospective randomized trial of clazosentan for the prevention of angiographic vasospasm. Propensity score matching was performed on the basis of age, gender, pre-existing heart conditions, hypertension, nicotine use, World Federation of Neurosurgical Societies scores, aneurysm location, clazosentan treatment, subarachnoid clot burden, and severity of angiographic vasospasm. Inferential statistics were used for group-wise comparisons.

RESULTS

One hundred twenty-three subjects were matched (41 received colloids, whereas 82 did not). The covariate balance and propensity score distributions were acceptable. There was no difference between the groups with respect to DIND (17 vs. 22%; p = 0.64) or the presence (48 vs. 51%; p = 0.71) or volume of delayed infarcts (volume >7.5 cm3; 62 vs. 48%; p = 0.41). Similarly, no differences were found on multivariate analysis between patients who did and did not have a positive fluid balance, although patients with severe angiographic vasospasm had more delayed infarcts with a negative fluid balance (p = 0.01). Among all subjects, the administration of colloids and a positive fluid balance were associated with worse outcomes on the NIHSS (p = 0.04) and modified Rankin (p = 0.02) scales, respectively.

CONCLUSIONS

Colloid administration and induction of a positive fluid balance during the vasospasm risk period may be associated with poor outcomes in specific patient groups. Patient selection is of utmost importance when managing the fluid status of patients with aneurysmal SAH.

The role of arterioles and the microcirculation in the development of vasospasm after aneurysmal SAH

Cerebral vasospasm of the major cerebral arteries, which is characterized by angiographic narrowing of those vessels, had been recognized as a main contributor to delayed cerebral ischemia (DCI) in subarachnoid hemorrhage (SAH) patients. However, the CONSCIOUS-1 trial revealed that clazosentan could not improve mortality or clinical outcome in spite of successful reduction of relative risk in angiographic vasospasm. This result indicates that the pathophysiology underlying DCI is multifactorial and that other pathophysiological factors, which are independent of angiographic vasospasm, can contribute to the outcome. Recent studies have focused on microcirculatory disturbance, such as microthrombosis and arteriolar constriction, as a factor affecting cerebral ischemia after SAH. Reports detecting microthrombosis and arteriolar constriction will be reviewed, and the role of the microcirculation on cerebral ischemia during vasospasm after SAH will be discussed.

Patient phenotypes associated with outcomes after aneurysmal subarachnoid hemorrhage: a principal component analysis

BACKGROUND AND PURPOSE

Predictors of outcome after aneurysmal subarachnoid hemorrhage have been determined previously through hypothesis-driven methods that often exclude putative covariates and require a priori knowledge of potential confounders. Here, we apply a data-driven approach, principal component analysis, to identify baseline patient phenotypes that may predict neurological outcomes.

METHODS

Principal component analysis was performed on 120 subjects enrolled in a prospective randomized trial of clazosentan for the prevention of angiographic vasospasm. Correlation matrices were created using a combination of Pearson, polyserial, and polychoric regressions among 46 variables. Scores of significant components (with eigenvalues>1) were included in multivariate logistic regression models with incidence of severe angiographic vasospasm, delayed ischemic neurological deficit, and long-term outcome as outcomes of interest.

RESULTS

Sixteen significant principal components accounting for 74.6% of the variance were identified. A single component dominated by the patients' initial hemodynamic status, World Federation of Neurosurgical Societies score, neurological injury, and initial neutrophil/leukocyte counts was significantly associated with poor outcome. Two additional components were associated with angiographic vasospasm, of which one was also associated with delayed ischemic neurological deficit. The first was dominated by the aneurysm-securing procedure, subarachnoid clot clearance, and intracerebral hemorrhage, whereas the second had high contributions from markers of anemia and albumin levels.

CONCLUSIONS

Principal component analysis, a data-driven approach, identified patient phenotypes that are associated with worse neurological outcomes. Such data reduction methods may provide a better approximation of unique patient phenotypes and may inform clinical care as well as patient recruitment into clinical trials.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov. Unique identifier: NCT00111085.

Low-dose intravenous heparin infusion in patients with aneurysmal subarachnoid hemorrhage: a preliminary assessment

OBJECT

Aneurysmal subarachnoid hemorrhage (aSAH) predisposes to delayed neurological deficits, including stroke and cognitive and neuropsychological abnormalities. Heparin is a pleiotropic drug that antagonizes many of the pathophysiological mechanisms implicated in secondary brain injury after aSAH.

METHODS

The authors performed a retrospective analysis in 86 consecutive patients with Fisher Grade 3 aSAH due to rupture of a supratentorial aneurysm who presented within 36 hours and were treated by surgical clipping within 48 hours of their ictus. Forty-three patients were managed postoperatively with a low-dose intravenous heparin infusion (Maryland low-dose intravenous heparin infusion protocol: 8 U/kg/hr progressing over 36 hours to 10 U/kg/hr) beginning 12 hours after surgery and continuing until Day 14 after the ictus. Forty-three control patients received conventional subcutaneous heparin twice daily as deep vein thrombosis prophylaxis.

RESULTS

Patients in the 2 groups were balanced in terms of baseline characteristics. In the heparin group, activated partial thromboplastin times were normal to mildly elevated; no clinically significant hemorrhages or instances of heparin-induced thrombocytopenia or deep vein thrombosis were encountered. In the control group, the incidence of clinical vasospasm requiring rescue therapy (induced hypertension, selective intraarterial verapamil, and angioplasty) was 20 (47%) of 43 patients, and 9 (21%) of 43 patients experienced a delayed infarct on CT scanning. In the heparin group, the incidence of clinical vasospasm requiring rescue therapy was 9% (4 of 43, p = 0.0002), and no patient suffered a delayed infarct (p = 0.003).

CONCLUSIONS

In patients with Fisher Grade 3 aSAH whose aneurysm is secured, postprocedure use of a low-dose intravenous heparin infusion may be safe and beneficial.

Early vs Delayed Cerebral Infarction After Aneurysm Repair After Subarachnoid Hemorrhage

BACKGROUND:

Cerebral infarction is a major contributor to poor outcome after subarachnoid hemorrhage (SAH). Although usually considered a complication of delayed cerebral ischemia, infarcts may also occur early, in relation to initial brain injury or aneurysm-securing procedures.

OBJECTIVE:

We analyzed the relative frequency and volume of early vs delayed infarcts after SAH and their relationship to hospital outcome.

METHODS:

Retrospective review of consecutive patients admitted with aneurysmal SAH over 4 years who had follow-up brain imaging 7 days or later after admission. Imaging 24 to 48-hours after aneurysm-securing procedures was reviewed to classify infarcts seen on final imaging as early or delayed. Infarct volumes were measured by perimeter tracing and infarct burden calculated for each patient.

RESULTS:

Of 250 eligible patients, 205 had follow-up imaging; infarcts were present in 61 patients. Of these, 29 had early infarcts, 16 had delayed infarcts, and 5 had both early and delayed infarcts. Eleven patients with infarcts did not undergo postprocedure computed tomography; these were presumptively classified as having late infarcts. Early and delayed infarcts contributed equally to infarct burden. Early infarcts were associated with aneurysm clipping (odds ratio: 4.2, 95% confidence interval: 1.8-9.5 compared with coiling), whereas delayed infarcts were almost always seen in association with angiographic vasospasm (odds ratio: 3.3, 95% confidence interval: 1.5-7.3). Patients with early as well as late infarcts, especially those with infarct burden more than 30 cm3 had worse hospital discharge disposition.

CONCLUSION:

Early infarction occurs frequently after SAH and contributes as much as delayed cerebral ischemia to infarct burden and hospital outcome. Efforts to better understand and modify contributors to early infarction appear warranted.

Subarachnoid Extension of Primary Intracerebral Hemorrhage is Associated With Poor Outcomes

Background and Purpose—

Extension of hemorrhage into the subarachnoid space is observed in primary intracerebral hemorrhage (ICH), yet the phenomenon has undergone limited study and is of unknown significance. The objective of this study is to evaluate the incidence, characteristics, and clinical consequences of subarachnoid hemorrhage extension (SAHE) in ICH on functional outcomes.

Methods—

Patients with primary ICH were enrolled into a prospective registry between December 2006 and June 2012. Patients were managed and serial neuroimaging was obtained per a structured protocol. Presence of any subarachnoid blood on imaging was identified as SAHE by expert reviewers blinded to outcomes. Regression models were developed to test whether the occurrence of SAHE was an independent predictor of functional outcomes as measured with the modified Rankin Scale.

Results—

Of 234 patients with ICH, 93 (39.7%) had SAHE. Interrater agreement for SAHE was excellent (kappa=0.991). SAHE was associated with lobar hemorrhage location (65% of SAHE vs 19% of non-SAHE cases; P <0.001) and larger hematoma volumes (median 23.8 vs 6.7; P <0.001). Fever (69.9% vs 51.1%; P =0.005) and seizures (8.6% vs 2.8%; P =0.07) were more common in patients with SAHE. SAHE was a predictor of death by day 14 (odds ratio, 4.45; 95% confidence interval, 1.88–10.53; P =0.001) and of higher (worse) modified Rankin Scale scores at 28 days (odds ratio, 1.76 per mRS point; 95% confidence interval, 1.01–3.05; P =0.012) after adjustment for ICH score.

Conclusions—

SAHE is associated with worse modified Rankin Scale independent of traditional ICH severity measures. Underlying mechanisms and potential treatments of SAHE require further study.

History and definition of delayed cerebral ischemia

A list of the vasospasm meetings is provided. The early descriptions of angiographic vasospasm and delayed cerebral ischemia are presented. Selected advances in knowledge in the field and some controversies are described. A proposal for definitions of neurological deterioration due to delayed cerebral ischemia, of cerebral infarction, and of vasospasm is reviewed.

Clinical, transcranial Doppler ultrasound, radiological features and, prognostic significance of delayed cerebral ischemia

OBJECTIVE

We aimed to investigate the profiles and prognostic values of delayed cerebral ischemia (DCI) and delayed cerebral infarction.

METHODS

IMASH (Intravenous Magnesium Sulphate for Aneurysmal Subarachnoid Hemorrhage) was registered at http://www.strokecenter.org/trials , and http://www.ClinicalTrials.gov (NCT00124150). Data of 327 patients were retrieved for logistic regression analyses.

RESULTS

Seventy-one (22%) patients developed DCI, and 35 (11%) patients developed delayed cerebral infarction. Only 18 (25%) patients with DCI and 7/35 (20%) patients with delayed cerebral infarction had mean middle cerebral artery velocities (transcranial Doppler ultrasound) over 120 cm/s. Regarding the prognostic significance of the components of DCI, delayed cerebral infarction predicted unfavorable outcome in terms of Extended Glasgow Outcome Scale (OR 3.1, 95% [CI] 1.3-7.8), poor outcome in terms of modified Rankin Scale (odds ratio [OR] 3.0, 95% confidence interval CI 1.2-7.7), and dependent activity of daily living in terms of Barthel Index (OR 3.6, 95% CI 1.4-9.2) at 6 months, after adjustments for other prognostic factors. On the other hand, clinical deterioration predicted inpatient mortality (OR 8.8, 95% CI 1.6-48.8) after adjustments for other prognostic factors.

CONCLUSIONS

Delayed cerebral ischemia and delayed cerebral infarction carried different prognostic values in aneurysmal subarachnoid hemorrhage.