A review of cerebral vasospasm in aneurysmal subarachnoid haemorrhage

Utility of Surveillance Angiography in Aneurysmal Subarachnoid Hemorrhage: A Retrospective Study of 223 Consecutive Patients

BACKGROUND

Patients with aneurysmal subarachnoid hemorrhage (aSAH) who survive the rupture are at risk for delayed neurologic deficits and cerebral infarction. The ideal method(s) of surveillance for cerebral vasospasm, and the link between radiographic vasospasm and delayed neurologic deficits, remain controversial. We instituted a postbleed day 7 angiography protocol with the stated goals of identification of vasospasm, improving neurologic outcomes, and possibly lowering cost of care.

METHODS

We conducted a quality improvement project in which we retrospectively analyzed consecutive cases of aSAH from a single institution over a 5-year period. Patients were excluded if they did not receive treatment for their aneurysm or were < 18 years of age. We analyzed demographic and outcome information for patients managed by protocolled angiography versus those who were managed by as-needed endovascular rescue therapy. Statistical tests were performed comparing means and proportions in both cohorts, as appropriate.

RESULTS

In total, 223 patients were identified who met inclusion criteria. In total, 157 patients were identified in the protocolled day 7 angiography group, and 66 were in the nonprotocolled angiography group. Demographics were similar between the day 7 angiogram and medical management cohorts, except for a higher mean age among the latter group (p = 0.016). The protocolled angiography group underwent a significantly greater number of angiograms (p < 0.001) and had a significantly higher cost of hospitalization ($240,327 vs. $205,719, p = 0.03), with no significant difference in rate of cerebral infarction, length of intensive care unit stay, length of hospital stay, discharge location, or discharge modified Rankin Score.

CONCLUSIONS

This cohort comparison analysis draws into question the practice of protocolized cerebral angiography in patients with aSAH.

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.

Effect of Cilostazol on Delayed Cerebral Infarction in Aneurysmal Subarachnoid Hemorrhage Using Explainable Predictive Modeling

The studies interpreting DCI, a complication of SAH, and identifying correlations are very limited. This study aimed to investigate the effect of cilostazol on ACV and DCI after coil embolization for ruptured aneurysms (n = 432). A multivariate analysis was performed and explainable artificial intelligence approaches were used to analyze the contribution of cilostazol as a risk factor on the development of ACV and DCI with respect to global and local interpretation. The cilonimo group was significantly lower than the nimo group in ACV (13.5% vs. 29.3; p = 0.003) and DCI (7.9% vs. 20.7%; p = 0.006), respectively. In a multivariate logistic regression, the odds ratio for DCI for the cilonimo group, female sex, and aneurysm size was 0.556 (95% confidence interval (CI), 0.351-0.879; p = 0.012), 3.713 (95% CI, 1.683-8.191; p = 0.001), and 1.106 (95% CI, 1.008-1.214; p = 0.034). The risk of a DCI occurrence was significantly increased with an aneurysm size greater than 10 mm (max 80%). The mean AUC of the XGBoost and logistic regression models was 0.94 ± 0.03 and 0.95 ± 0.04, respectively. Cilostazol treatment combined with nimodipine could decrease the prevalence of ACV (13.5%) and DCI (7.9%) in patients with aSAH.

Study protocol for SFX-01 after subarachnoid haemorrhage (SAS): a multicentre randomised double-blinded, placebo controlled trial

INTRODUCTION

Subarachnoid haemorrhage (SAH) from a ruptured cerebral aneurysm carries high morbidity and mortality. Despite huge advances in techniques to secure the aneurysm, there has been little progress in the treatment of the deleterious effects of the haemorrhage.Sulforaphane is an Nrf2 inducer with anti-oxidant and anti-inflammatory properties. It has been shown to improve clinical outcome in experimental models of SAH, but is unstable. SFX-01 (Evgen Pharma) is a novel composition comprised of synthetic sulforaphane stabilised within an α-cyclodextrin complex. On ingestion, the complex releases sulforaphane making SFX-01 an ideal vehicle for delivery of sulforaphane.

METHODS AND ANALYSIS

The objective of the study is to assess the safety, pharmacokinetics and efficacy of SFX-01. This is a prospective, multicentre, randomised, double-blind placebo-controlled trial in patients aged 18-80 years with aneurysmal subarachnoid haemorrhage in the previous 48 hours. 90 patients will be randomised to receive SFX-01 (300 mg) or placebo two times per day for up to 28 days.Safety will be assessed using blood tests and adverse event reporting.Pharmacokinetics will be assessed based on paired blood and cerebrospinal fluid (CSF) sulforaphane levels on day 7. A subgroup will have hourly samples taken during 6 hours post-dosing on days 1 and 7. Pharmacodynamics will be assessed by haptoglobin and malondialdehyde levels, and maximum flow velocity of middle cerebral artery will be measured by transcranial Doppler ultrasound.Clinical outcomes will be assessed at days 28, 90 and 180 with modified Rankin Scale, Glasgow Outcome Score, SAH Outcome Tool, Short Form-36, Brain Injury Community Rehabilitation Outcome Scales and Check List for Cognitive and Emotional consequences following stroke. MRI at 6 months including quantitative susceptibility mapping and volumetric T1 will measure iron deposition and cortical volume.Safety, CSF sulforaphane concentration and middle cerebral artery flow velocity will be primary outcomes and all others secondary.

ETHICS AND DISSEMINATION

Ethical approval was obtained from South Central Hampshire A committee. Outcomes of the trial will be submitted for publication in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT02614742.

Cerebral vasospasm after endoscopic fenestration of a temporal arachnoid cyst in a child-a case report and review of the literature

INTRODUCTION

Intracranial arachnoid cysts (ACs) represent rare extra-axial CSF-containing lesions. Surgical management mainly depends on the cyst location and its size. Nevertheless, pure endoscopic fenestration represents a relatively straightforward and safe technique, and-in most cases-the treatment of choice for symptomatic intracranial ACs. The postoperative complication rate of the procedure is low including subdural hematomas, hygromas, and intraparenchymal hemorrhages. Symptomatic cerebral vasospasm after endoscopic treatment of ACs is a very uncommon event.

CASE REPORT/RESULTS

To the authors' knowledge, this adverse event in children has not yet been reported in the literature yet. The authors present a case of a 9-year-old child developing an early symptomatic cerebral vasospasm with an insignificant secondary ischemia following endoscopic fenestration of a large temporal arachnoid cyst.

DISCUSSION

The clinical approach, possible pathogenesis, and the therapeutic strategy is discussed particularly with regard to the literature.

Alpha Calcitonin Gene-Related Peptide Increases Cerebral Vessel Diameter in Animal Models of Subarachnoid Hemorrhage: A Systematic Review and Meta-analysis

Delayed cerebral ischemia (DCI) is a life-threatening complication after subarachnoid hemorrhage. There is a strong association between cerebral vessel narrowing and DCI. Alpha calcitonin gene-related peptide (αCGRP) is a potent vasodilator, which may be effective at reducing cerebral vessel narrowing after subarachnoid hemorrhage (SAH). Here, we report a meta-analysis of data from nine in vivo animal studies identified in a systematic review in which αCGRP was administered in SAH models. Our primary outcome was change in cerebral vessel diameter and the secondary outcome was change in neurobehavioral scores. There was a 40.8 ± 8.2% increase in cerebral vessel diameter in those animals treated with αCGRP compared with controls (p < 0.0005, 95% CI 23.7–57.9). Neurobehavioral scores were reported in four publications and showed a standardized mean difference of 1.31 in favor of αCGRP (CI −0.49 to 3.12). We conclude that αCGRP reduces cerebral vessel narrowing seen after SAH in animal studies but note that there is insufficient evidence to determine its effect on functional outcomes.

A non-human primate model of aneurismal subarachnoid hemorrhage (SAH)

Aneurismal subarachnoid hemorrhage (SAH) is relatively rare form of hemorrhagic stroke, which produces significant social and medical challenges. As it affects people in their high productivity age and leaves 50 % of them dead and almost 70 % of survivors disabled, many of them severely, the reasons of such a dismal outcome have been intensively researched all over the world. Nevertheless, despite more than a half a century of clinical and scientific effort and dramatic improvement of surgical repair of aneurysms, the causes of poor outcome remain enigmatic. Introduction of numerous in vitro and in vivo models to study the unleashed by SAH mechanisms that injured the brain significantly advanced our understanding of biology of cerebral vessels, brain responses to intracranial pressure changes, and the presence of blood clot in subarachnoid space. One of the most important animal models that significantly contributed to those advances has been a non-human primate model introduced at the Bryce Weir laboratory in the University of Alberta, Canada, in 1984. Since then, this model, with some modifications, has been successfully used in several animal laboratories in the USA, Canada, and Japan. We present the model characteristics and describe in details medical, surgical, imagining techniques that we have used at the Surgical Neurology Branch of the National Institute of Neurological Disorders and Stroke from 1989.

Intracranial hypotension caused by cisternal irrigation for vasospasm after subarachnoid hemorrhage: a case report

Introduction

Vasospasm is the most common cause of complication after a subarachnoid hemorrhage and tremendous efforts have been made to prevent it. A subarachnoid clot is the cause of the vasospasm and dissolving and washing it out is considered to be the best practice. Cisternal irrigation with urokinase and ascorbic acid has been widely used due to its proven effect.

Case presentation

A 60-year-old Japanese male presented with a severe headache was diagnosed with a subarachnoid hemorrhage and an immediate surgical obliteration was successfully performed. After clipping the aneurysm, a cisternal drainage tube was placed in the chiasmatic cistern. In order to clear the thick subarachnoid hemorrhage, a cisternal irrigation was performed. However, his consciousness deteriorated and his left pupil became dilated on the next day. A T1 sagittal magnetic resonance imaging scan showed an evidence of marked brain sagging with mild tonsillar descent. We continued intensive hydration and head-down positioning and the brain sagging was shown to have improved in the follow-up magnetic resonance imaging scan.

Conclusions

We present a case in which our patient experienced brain sagging after a cisternal irrigation of a subarachnoid hemorrhage. A subdural hematoma and low intracranial pressure suggested intracranial hypotension. Sagittal magnetic resonance imaging images are useful to evaluate brain sagging and are shown sequentially here in our case report.

Endovascular methods for the treatment of intracranial cerebral aneurysms

This article briefly discusses the clinical features, natural history, and epidemiology of intracranial cerebral aneurysms, along with current diagnostic imaging techniques for their detection. The main focus is on the basic techniques used in endovascular coiling of ruptured and nonruptured saccular intracranial cerebral aneurysms. After a discussion of each technique, a short review of the results of each form of treatment is given, concentrating on reported large case series. Specific complications related to the endovascular treatment of saccular intracranial aneurysms are then discussed.

Vasospasm after arteriovenous malformation rupture

OBJECTIVE

Vasospasm and resultant clinical deterioration caused by delayed cerebral ischemia (CD-CDI) are a considerable source of morbidity after aneurysmal subarachnoid hemorrhage (SAH). Although they are a relatively common cause of spontaneous SAH, AVM rupture and ensuing vasospasm are rarely reported.

METHODS

We reviewed our own series of 122 patients with AVMs. Seventy-three patients sustaining 84 hemorrhages were analyzed. In addition, we performed a review of the literature of vasospasm after AVM rupture.

RESULTS

Seventy of 84 hemorrhages (83%) had an intraparenchymal component, 27 (32%) a subarachnoid component, and 51 (61%) had an intraventricular component. No patients experienced CD-DCI, and of the 84 hemorrhages reported, only one patient experienced mild angiographic vasospasm (1.1%). Alternatively, this finding represents 1 in 34 cases (2.9%) who underwent definitive angiography between the fourth and fifteenth day after the hemorrhage. Nineteen additional cases of angiographic vasospasm after AVM rupture are reported in the literature. The mean age of these patients was 33 years; there was a 1.25:1 female to male predominance in this group. One-half of these patients had an intraparenchymal hemorrhage, and only 56% of them had SAH. All patients had intraventricular hemorrhage when assessed. The median time to onset of vasospasm was nine days. Across four series, the rate of angiographic spasm after SAH from an AVM was 6.3% (9/142 cases).

CONCLUSIONS

Even in cases of SAH from AVMs, angiographic vasospasm after AVM rupture is relatively rare. We thus do not recommend empiric delayed angiography to assess for vasospasm in these patients. Nevertheless, it does remain a rare possibility and should be considered in those with CD-DCI.

A clinical review of cerebral vasospasm and delayed ischaemia following aneurysm rupture

The continuation of a review of delayed vasospasm after aneurysmal subarachnoid haemorrhage, originally published in 1994 and partially updated at the ninth vasospasm conference in Turkey, is presented. Further online and physical searches have been made of the relevant literature. The incidence of delayed ischaemic deficit (DID) or symptomatic vasospasm reported in 1994 was 32.5% in over 30,000 reported cases. In recent years, 1994-2009, it was 6,775/23,806, or 28.5%. Many of the recent reports did not specify whether a calcium antagonist was used routinely, and when this was stated (usually nimodipine or nicardipine), DID was noted in 22.0% of 10,739 reported patients. The outcome of delayed ischaemia in the earlier survey was a death rate of 31.6%, with favourable outcomes in 36.2%. In recent reports, though with fewer than 1,000 patients, the outcome is possibly better, with death in 25.6% and good outcome in 54.1%. It thus appears likely that delayed vasospasm is still common but less so, and that the overall outcome has improved. This may be due to the more widespread use of calcium antagonists and more effective fluid management. A number of other mechanical and drug treatments are also mentioned.

Alteration in voltage-dependent calcium channels in dog basilar artery after subarachnoid hemorrhage

Object

The L-type Ca++ channel antagonists like nimodipine have limited efficacy against vasospasm after subarachnoid hemorrhage (SAH). The authors tested the hypothesis that this is because SAH alters these channels, rendering them less responsible for contraction.

Methods

Basilar artery smooth muscle cells were isolated 4, 7, and 21 days after SAH in dogs, and Ca++ channel currents were recorded in 10-mmol/L barium. Proteins for α1 subunits of L-type Ca++ channels were measured by immunoblotting and isometric tension recordings done on rings of the basilar artery.

Results

High voltage–activated (HVA) Ca++ channel currents were significantly decreased and low voltage–activated (LVA) currents increased during vasospasm 4, 7, and 21 days after SAH (p < 0.05). Vasospasm was associated with a significant decrease in the number of cells with negligible LVA current while the number of cells in which the LVA current formed greater than 50% of the maximal current increased (p < 0.01). Window currents through LVA and HVA channels were significantly reduced. All changes correlated with the severity of vasospasm. There was an increase in protein for Cav3.1 and Cav3.3 α1 subunits that comprise T-type Ca++ channels, a decrease in L-type (Cav1.2 and Cav1.3) and an increase in R-type (Cav2.3) Ca++ channel α1 subunits. Functionally, however, isometric tension studies showed vasospastic arteries still relaxed with nimodipine.

Conclusions

Voltage-dependent Ca++ channels are altered in cerebral arteries after SAH. While decreased L-type channels may account for the lack of efficacy of nimodipine clinically, there may be other reasons such as inadequate dose, effect of nimodipine on other cellular targets, and mechanisms of vasospasm other than smooth muscle contraction mediated by activation of L-type Ca++ channels.

Involvement of epidermal growth factor receptor—protein tyrosine kinase transactivation in endothelin-1—induced vascular contraction

Object. Endothelin-1 (ET-1) is one of the major inducers of vasospasm following subarachnoid hemorrhage (SAH). It is generally accepted that extracellular signal—regulated kinase 1 and 2 (ERK1/2) are involved in ET-1—induced vascular contraction. In addition, ET-1 transactivates epidermal growth factor receptor (EGFR) protein tyrosine kinase (PTK), which leads to ERK1/2 stimulation. Therefore, the authors examined whether EGFR—PTK transactivation contributes to ET-1—induced vascular contraction in this study.

Methods. Mitogen-activated protein kinase inhibitor, PD98059, inhibited ET-1—induced ERK1/2 stimulation in rabbit basilar artery (BA) vascular smooth-muscle cells (VSMCs). Moreover, PD98059 inhibited ET-1—induced contraction of rabbit BA rings. A specific inhibitor of EGFR PTK, AG1478, inhibited ET-1—induced EGFR—PTK transactivation, ERK1/2 stimulation, and contraction of BA rings in a concentration-dependent manner. The concentration of AG1478 required for 50% inhibition of the ET-1—induced contraction of BA rings was similar to that for ET-1—induced EGFR—PTK transactivation. Furthermore, AG1478 also inhibited ET-1—induced BA vasospasm in vivo.

Conclusion. The results indicate that EGFR—PTK transactivation pathway plays an important role in ET-1—induced vascular contraction.

Characterization of Ca2+ channels involved in endothelin-1-induced contraction of rabbit basilar artery

This study attempted to characterize Ca2+ channels involved in endothelin-1-induced contraction of rabbit basilar artery using whole-cell patch-clamp and measurement of intracellular free Ca2+ concentration. Endothelin-1 activates two types of Ca2+-permeable nonselective cation channels (NSCC-1 and NSCC-2) and a store-operated Ca2+ channel (SOCC) in addition to the voltage-operated Ca2+ channel (VOCC). These channels can be discriminated using Ca2+ channel blockers, SK&F 96365 and LOE 908. Tension study was conducted to clarify the Ca2+ channels involved in endothelin-1-induced contraction of basilar artery. Endothelin-1-induced basilar artery contraction is fully dependent on extracellular Ca2+ influx. Based on sensitivity to nifedipine, an L-type VOCC blocker, VOCCs have a minor role in endothelin-1-induced contraction. Both LOE 908 and SK&F 96365 inhibit endothelin-1-induced contraction in a concentration-dependent manner, and their combination abolished it. The median inhibitory concentrations of these blockers for endothelin-1-induced contraction correlated well with those of the endothelin-1-induced [Ca2+]i responses. Thus, the inhibitory action of these blockers on endothelin-1-induced contraction may be mediated by blockade of NSCC-1, NSCC-2, and the SOCC. Extracellular Ca2+ influx through NSCC-1, NSCC-2, and SOCC may be essential for endothelin-1-induced basilar artery contraction.

Reduced verapamil inhibition of endothelin-1-constricted rabbit basilar artery due to enhanced non L-type Ca(2+)-channel-dependent constriction

This study tested whether (1) L-type Ca(2+) channel blockade and extracellular Ca(2+) removal prior to endothelin-1, as compared to during the endothelin-1 constriction, resulted in lesser inhibition, and (2) the reduced inhibition due to prior L-type Ca(2+) channel blockade resulted from enhanced non L-type Ca(2+)-channel-dependent constriction. Pretreatment of rabbit basilar artery in vitro with 1 microM verapamil, an L-type Ca(2+) channel blocker, inhibited 3, 10, 30, and 100 nM endothelin-1 constrictions to a lesser extent than verapamil addition during the plateau endothelin-1 constriction. Ni(2+) (0.03 and 0.1 mM), a nonselective cation channel blocker, relaxed the plateau endothelin-1 constrictions in vessels pretreated with verapamil to greater magnitudes than vessels unexposed to verapamil. Extracellular Ca(2+) removal prior to 10, 30, and 100 nM endothelin-1 also inhibited the endothelin-1 constrictions to smaller magnitudes than Ca(2+) removal during the plateau endothelin-1 constrictions. These results suggest that the reduced inhibition of the endothelin-1 constriction following pretreatment with L-type Ca(2+) channel blocker or Ca(2+)-free solution, as compared to addition of these agents during the endothelin-1 constriction, is the result of non L-type Ca(2+) channel opening and enhanced Ca(2+)-independent constriction, respectively.

Aggressive management of aneurysmal subarachnoid haemorrhage based on a papaverine angioplasty protocol

The aim of this study was to analyse the results of intensive therapy unit management of aneurysmal subarachnoid haemorrhage incorporating angioplasty in the protocol. Two hundred consecutive patients were treated using a detailed protocol that included nimodipine, early aneurysm repair, and surveillance angiography. Angiography was performed on days 5 to 7 (or when the clinical state suggested the presence of vasospasm). If angiographic vasospasm was identified, irrespective of whether clinical vasospasm was present or absent, papaverine was selectively administered. In patients with vasospasm blood pressure was elevated to 160-180 mmHg and selective papaverine administration was repeated daily until vasospasm resolved. In cases requiring more frequent administration of papaverine, or in whom papaverine failed to adequately reverse spasm, balloon angioplasty was considered and for clinically refractory cases barbiturate coma was introduced. 43% of patients underwent papaverine administration and of these the average number of separate papaverine procedures was four (maximum 23). 26% of patients developed neurological deficits though to be due to vasospasm whilst 17% underwent papaverine angioplasty without clinical signs of vasospasm. Twelve patients (6%) were entered into barbiturate coma. There was a 5.5% mortality and no difference in outcome between patients who developed angiographic vasospasm and those who did not. For those developing clinical vasospasm, 71% were independent and 10% were dead at follow up compared with 84% reaching independent grades and 4% dead in those not developing clinical vasospasm. These differences failed to reach a significant difference. The average Intensive Therapy Unit stay for aneurysmal subarachnoid haemorrhage patients was 13.1 days with a mean cost to the hospital of $AUD 24,379. This protocol appears to be both a clinically and cost effective method of managing aneurysmal subarachnoid haemorrhage.

Role of extracellular Ca2+ in subarachnoid hemorrhage-induced spasm of the rabbit basilar artery

BACKGROUND AND PURPOSE

The role of extracellular Ca2+ in the maintenance of chronic vasospasm after subarachnoid hemorrhage (SAH) is largely unknown. Indeed, studies thus far have been limited to demonstrations that L-type Ca(2+)-channel antagonists were unable to reverse the spasm. This study tested whether SAH-induced vasospasm is maintained, at least in part. through the influx of extracellular Ca2+ and whether the influx of extracellular Ca2+ occurs through L-type Ca2+ channels and possibly, in addition, through store operated channels (SOCs). Furthermore, as there is considerable evidence in the literature to suggest that the spasm is mediated through endothelin-1 (ET-1) release, we tested whether the Ca2+ dependency of the spasm was consistent with the mediation of the spasm by ET-1.

METHODS

Chronic spasm of the basilar artery was induced in a double SAH rabbit model. Relaxation of SAH-, ET-1-, serotonin-, and KC1-constricted basilar artery in response to Ca(2+)-free solution, verapamil, and Ni2+ was measured in situ with the use of a cranial window.

RESULTS

SAH induced 23% constriction of the basilar artery. Ca(2+)-free solution and 1 mumol/L verapamil reversed the constriction of SAH vessels by 60% and 17%, respectively. In contrast, control vessels challenged with 40 to 50 mmol/L KCl, which induced 34% constriction, relaxed in response to Ca(2+)-free solution and verapamil by 98% and 89%, respectively. In SAH vessels, verapamil followed by 0.1 mmol/L Ni2+, which is known to block SOCs, induced a combined relaxation of 67%. Control vessels challenged with 3 nmol/L ET-1, which induced a magnitude of constriction similar to that of SAH (29%), relaxed in response to Ca(2+)-free solution, verapamil, and verapamil plus Ni2+ by 69%, 20%, and 50%, respectively (P > .05) versus respective values in SAH vessels). In contrast, control vessels challenged with 2 to 8 mumol/L serotonin, which induced a magnitude of constriction similar to those of SAH and ET-1 (22%), completely relaxed in response to Ca(2+)-free solution and verapamil.

CONCLUSIONS

These results demonstrate that the maintenance of chronic spasm in the two-hemorrhage rabbit model after SAH is due to smooth muscle cell contractile mechanisms partly dependent on the influx of extracellular Ca2+. The influx of extracellular Ca2+ results from the opening of L-type Ca2+ channels and an additional channel or channels. We speculate that the L-type Ca2+ channel-independent influx of extracellular Ca2+ results from the opening of SOCs. The Ca(2+)-dependent characteristics of the spasm likely reflect the mediation of the spasm by ET-1.

The effect of nimodipine monotherapy and combined treatment with ketamine and lignocaine in aneurysmal subarachnoid haemorrhage

The clinical effects of nimodipine monotherapy were compared with the effects of nimodipine combined with ketamine and lignocaine (combination therapy) in a single-centre, one investigator, open study in patients with proven aneurysmal subarachnoid haemorrhage (aSAH). After clipping of the aneurysm, nimodipine was administered intravenously until day 5-7 after clipping. Thereafter the intravenous nimodipine was substituted by oral doses of nimodipine. These were decreased gradually and then discontinued within the following 6 days. For combination therapy, nimodipine was given together with both a bolus injection of 1 microgram/kg ketamine followed by an infusion of the drug at a rate of 3 micrograms/kg/min and a bolus injection of 1.5 mg/kg lignocaine followed by an infusion of the drug at a rate of 12 micrograms/kg/min. During the study period, 173 patients were admitted to the hospital with subarachnoid haemorrhage (SAH). Of these patients, 115 with a proven aneurysm were operated on and evaluated: 66 patients received nimodipine monotherapy and 49 were given nimodipine combined with ketamine and lignocaine. These subgroups were comparable in terms of the baseline characteristics (age, Hunt and Hess score). The (baseline corrected) Hunt and Hess scores after surgery and a 0-5 clinical outcome score were applied as indices for clinical effects. Patients receiving nimodipine monotherapy and combined therapy showed a significant clinical improvement compared to baseline (P = 0.001 and P = 0.006, respectively). The beneficial effect of nimodipine monotherapy is in line with previous double-blind, placebo-controlled studies. Although nimodipine monotherapy seems to be more effective than combined treatment, this was not statistically significant. Our data indicate that combined treatment with ketamine and lignocaine is not more effective than nimodipine monotherapy in patients with mild aSAH, but this does not rule out an effect in severe cases. There was no indication of a pharmacodynamic interaction between nimodipine and co-medication. No serious or clinically relevant adverse reactions were noted during the study.

Traumatic subarachnoid hemorrhage and its treatment with nimodipine. German tSAH Study Group

A prospective, randomized, double-blind, placebo-controlled study of nimodipine used to treat traumatic subarachnoid hemorrhage (tSAH) was conducted in 21 German neurosurgical centers between January 1994 and April 1995. One hundred twenty-three patients with tSAH appearing on initial computerized tomography (CT) scanning were entered into the study. Requirements for inclusion included age between 16 and 70 and admission into the study within 12 hours after head injury, regardless of the patient's level of consciousness. Eligible patients received either a sequential course of intravenous and oral nimodipine or placebo treatment for 3 weeks. Patients were closely monitored using clinical neurology, computerized tomography, laboratory, and transcranial Doppler ultrasound parameters. Patients treated with nimodipine had a significantly less unfavorable outcome (death, vegetative survival, or severe disability) at 6 months than placebo-treated patients (25% vs. 46%, p = 0.02). The relative reduction in unfavorable outcome in the nimodipine-treated group was even higher (55%, p = 0.002) when only patients who complied with the protocol were considered.

Relaxation of subarachnoid hemorrhage-induced spasm of rabbit basilar artery by the K+ channel activator cromakalim

BACKGROUND AND PURPOSE

Cerebral vasospasm resulting from subarachnoid hemorrhage (SAH) is refractory to most vasodilators. However, despite evidence that a mechanism underlying the vasospasm may be smooth muscle cell membrane depolarization resulting from decreased K+ conductance, the ability of K+ channel activators to relax the spasm has not been thoroughly investigated. The purpose of this study, therefore, was to investigate whether K+ channel activation selectively relaxes SAH-induced vasospasm.

METHODS

Three days after SAH in the rabbit, relaxation of the basilar artery in response to the K+ channel activator cromakalim as well as to staurosporine (protein kinase C antagonist), forskolin (adenylate cyclase activator), and sodium nitroprusside (guanylate cyclase activator) was measured in situ with the use of a cranial window. Relaxation in response to these agents was also investigated in control vessels contracted with serotonin. Membrane potential of the smooth muscle cells of the basilar artery from SAH and control rabbit was measured in vitro with the use of intracellular microelectrodes.

RESULTS

Cromakalim completely relaxed the SAH-induced spastic basilar artery, while staurosporine, forskolin, and sodium nitroprusside were significantly less efficacious. In contrast, sodium nitroprusside and forskolin were more efficacious relaxants in serotonin-contracted control vessels than in SAH vessels. The K+ channel blocker glyburide and high [K+] prevented cromakalim-induced relaxation. Glyburide did not inhibit forskolin-induced relaxation of serotonin-contracted control vessels. Cromakalim concentration-dependently repolarized spastic basilar artery smooth muscle cells, and the repolarization was prevented by glyburide.

CONCLUSIONS

These results suggest that K+ channel activation selectively relaxes SAH-induced vasospasm. We speculate that the ability of K+ channel activators to selectively relax the spasm may be due, at least in part, to the underlying inhibition of K+ channels after SAH.

[Pharmacological treatment of vasospasm in subarachnoid hemorrhage]

Pharmacological treatment of vasospasm in subarachnoid haemorrhage (SAH) is founded on prevention and treatment of arterial narrowing and delayed ischaemic deficits. Safety and efficacy of different agents have been studied and trials classified according to the level of evidence proposed by the "Stroke Council" of the American Heart Association. Early intracisternal fibrinolysis can prevent vasospasm (level III to V of evidence, grade C). Pharmacological treatment is based on few drugs. Nimodipine reduces poor outcome related to vasospasm, but does not affect angiographic vessel caliber (level of evidence I and II, grade A). Its use is strongly recommended. Nicardipine decreases symptomatic and angiographic vasospasm, but does not affect outcome (level of evidence I to V, grade B). Tirilazad associated with nimodipine prevents delayed ischaemic deficits due to vasospasm and improves outcome in male patients. Intra-arterial infusion of papaverine associated with transluminal angioplasty can improve symptomatic vasospasm, resistant to conventional therapy (level of evidence IV to V, grade C). Pharmacological treatment of vasospasm associated with specific management founded on pathophysiology of SAH has improved patients outcome.