A randomized controlled trial of high-dose intravenous nicardipine in aneurysmal subarachnoid hemorrhage. A report of the Cooperative Aneurysm Study

Efficacy of prophylactic nimodipine for delayed ischemic deficit after subarachnoid hemorrhage: a metaanalysis

The authors report findings from a metaanalysis of all published randomized trials of prophylactic nimodipine used in patients who have experienced subarachnoid hemorrhage (SAH). Seven trials were included with a total of 1202 patients suitable for evaluation. Eight outcome measures were examined, including good versus other outcome, good or fair outcome versus other outcome, overall mortality, deficit and/or death attributed to vasospasm, infarction rate as judged by computerized tomography (CT), and deficit and/or death from rebleeding. Nimodipine improved outcome according to all measures examined. The odds of good and of good plus fair outcomes were improved by ratios of 1.86:1 and 1.67:1, respectively, for nimodipine versus control(p<0.005 for both measures). The odds of deficit and/or mortality attributed to vasospasm and CT-assessed infarction rate were reduced by ratios of 0.46:1 to 0.58:1 in the nimodipine group (p<0.008 for all measures). Overall mortality was slightly reduced in the nimodipine group, but the trend was not statistically significant. The rebleeding rate was not increased by nimodipine. A metaregression yielded findings indicating that the treatment effect of nimodipine in individual trials was positively correlated with the severity of SAH in enrolled patients. Although the majority of individual trials examined did not have statistically significant results at the p<0.01 level according to most outcome measures, the metaanalyses confirmed the significant efficacy of prophylactic nimodipine in improving outcome after SAH under the conditions used in these trials.

Randomized, double-blind, vehicle-controlled trial of tirilazad mesylate in patients with aneurysmal subarachnoid hemorrhage: a cooperative study in Europe, Australia, and New Zealand

Tirilazad mesylate, a nonglucocorticoid 21-aminosteroid, has been shown in experimental models to reduce vasospasm following subarachnoid hemorrhage (SAH) and to reduce infarct size from focal cerebral ischemia. To test whether treatment with tirilazad would reduce ischemic symptoms from vasospasm and improve overall outcome in patients with ruptured aneurysms, a prospective randomized, double-blind, vehicle-controlled trial was conducted at 41 neurosurgical centers in Europe, Australia, and New Zealand. One thousand twenty-three patients were randomly assigned to receive 0.6, 2, or 6 mg/kg per day of intravenously administered tirilazad or a placebo containing the citrate vehicle. All patients were also treated with intravenously administered nimodipine. Patients receiving 6 mg/kg per day of tirilazad had reduced mortality (p = 0.01) and a greater frequency of good recovery on the Glasgow Outcome Scale 3 months after SAH (p = 0.01) than similar patients treated with vehicle. There was a reduction in symptomatic vasospasm in the group that received 6 mg/kg per day tirilazad; however, the difference was not statistically significant (p = 0.048). The benefits of treatment with tirilazad were predominantly shown in men rather than in women. There were no material differences between the outcomes in the groups treated with 0.6 and 2 mg/kg tirilazad per day and the group treated with vehicle. Tirilazad was well tolerated at all three dose levels. These observations suggest that tirilazad mesylate, at a dosage of 6 mg/kg per day, is safe and improves overall outcome in patients (especially in men) who have experienced an aneurysmal SAH.

Gender-related differences in aneurysmal subarachnoid hemorrhage

Female gender is a recognized risk factor for the occurrence of aneurysmal subarachnoid hemorrhage. In the present study the authors analyzed differences in admission characteristics and outcome between 578 women (64%) and 328 men (36%) who were enrolled in a recently completed clinical trial. The female-to-male ratio was nearly 2:1. The women in the study were older than the men (mean age 51.4 years vs 47.3 years, respectively, p<0.001). Female patients harbored aneurysms of the internal carotid artery more frequently than male patients (36.8% vs. 18.0%, p<0.001) and more often had multiple aneurysms (32.4% vs. 17.6%, p<0.001). On the other hand, anterior cerebral artery aneurysms were more commonly encountered in men (46.1% in men vs. 26.6% in women, p<0.001). Other baseline prognostic factors were balanced between the gender groups. Surgery was performed equally in both sexes (98%), although the time to operation was shorter for women (mean 3.6 days for women vs. 5.3 days for men, p = 0.0002). In the placebo group, the occurrence of vasospasm was not statistically different between the two groups. Primary causes of death and disability were the same, and favorable outcome rates at 3 months were not statistically different between the genders (69.7% for women vs. 73.4% for men, p = 0.243). The odds of a favorable outcome in women versus one in men were not statistically significant either before of after adjustment for age. These observations lead the authors to suggest that although women are older and harbor more aneurysms, the 3-month outcome for women and men who experience aneurysmal subarachnoid hemorrhage is the same.

Relationship between the volume of craniotomies for cerebral aneurysm performed at New York state hospitals and in-hospital mortality

BACKGROUND AND PURPOSE

After a craniotomy for cerebral aneurysm, postoperative mortality can be significant. Previous studies have shown that hospitals performing frequent high-risk procedures (such as coronary artery bypass) have a lower mortality than hospitals where these procedures are performed infrequently.

METHODS

The Statewide Planning and Research Cooperative System of the New York State Department of Health reviewed all discharges in New York State from 1987 through 1993 for the diagnoses of subarachnoid hemorrhage and/or cerebral aneurysm and for patients with the procedure code for craniotomy for ruptured or unruptured cerebral aneurysm. In-hospital mortality and length of stay were examined in relation to the volume of craniotomies for aneurysm performed at each individual hospital.

RESULTS

A total of 15,376 discharges for subarachnoid hemorrhage and 5638 craniotomies for aneurysm were tabulated in 208 hospitals. For all patients who underwent craniotomy for ruptured cerebral aneurysm (n = 4034), there was a 43% (95% confidence interval, 29% to 57%) reduction in mortality rate in hospitals performing more than 30 craniotomies per year for cerebral aneurysm compared with hospitals performing less surgery (8.8% versus 15.5%, P < .0001). For all patients who underwent craniotomy for unruptured cerebral aneurysm (n = 1604), there was an identical 43% (95% confidence interval, 14% to 73%) reduction in mortality in hospitals performing more than 30 craniotomies per year for cerebral aneurysm (4.6% versus 8.1%, P = .0087).

CONCLUSIONS

Hospitals that frequently perform aneurysm operations have lower mortality rates for patients undergoing craniotomy for cerebral aneurysm than hospitals that perform fewer operations.

[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.

Tissue plasminogen activator for acute ischemic stroke

BACKGROUND

Thrombolytic therapy for acute ischemic stroke has been approached cautiously because there were high rates of intracerebral hemorrhage in early clinical trials. We performed a randomized, double-blind trial of intravenous recombinant tissue plasminogen activator (t-PA) for ischemic stroke after recent pilot studies suggested that t-PA was beneficial when treatment was begun within three hours of the onset of stroke.

METHODS

The trial had two parts. Part 1 (in which 291 patients were enrolled) tested whether t-PA had clinical activity, as indicated by an improvement of 4 points over base-line values in the score of the National Institutes of Health stroke scale (NIHSS) or the resolution of the neurologic deficit within 24 hours of the onset of stroke. Part 2 (in which 333 patients were enrolled) used a global test statistic to assess clinical outcome at three months, according to scores on the Barthel index, modified Rankin scale, Glasgow outcome scale, and NIHSS:

RESULTS

In part 1, there was no significant difference between the group given t-PA and that given placebo in the percentages of patients with neurologic improvement at 24 hours, although a benefit was observed for the t-PA group at three months for all four outcome measures. In part 2, the long-term clinical benefit of t-PA predicted by the results of part 1 was confirmed (global odds ratio for a favorable outcome, 1.7; 95 percent confidence interval, 1.2 to 2.6). As compared with patients given placebo, patients treated with t-PA were at least 30 percent more likely to have minimal or no disability at three months on the assessment scales. Symptomatic intracerebral hemorrhage within 36 hours after the onset of stroke occurred in 6.4 percent of patients given t-PA but only 0.6 percent of patients given placebo (P < 0.001). Mortality at three months was 17 percent in the t-PA group and 21 percent in the placebo group (P = 0.30).

CONCLUSIONS

Despite an increased incidence of symptomatic intracerebral hemorrhage, treatment with intravenous t-PA within three hours of the onset of ischemic stroke improved clinical outcome at three months.

Clinical potential for the use of neuroprotective agents. A brief overview

"Stroke treatment seems to be entering a golden age ...." Fisher's observation not only applies to ischemic stroke, but to all the conditions described above, and in the future, possibly (and quite speculatively), to other neurologic diseases, such as multiple sclerosis, amyotrophic lateral sclerosis, even radiation therapy and Bell's palsy. Physicians must sharpen their criteria for decisions regarding therapy and must" ... be prepared to accept what is actually known from scientific data ... rather than to rely on instinct, clinical impression, or the need to do something rather than nothing."

Causes of morbidity and mortality after ruptured aneurysm surgery in a series of 230 patients. The importance of control angiography

BACKGROUND AND PURPOSE

The purpose of this study was to determine the causes of morbidity and mortality after surgery for ruptured aneurysms.

METHODS

Two hundred thirty consecutive patients were studied. Initial hemorrhage volume and vasospasm were evaluated preoperatively with CT, transcranial Doppler ultrasonography, and angiography. Nimodipine infusion was started before surgery. Preoperative clinical status was evaluated according to Hunt and Hess grading criteria. Surgery was performed early in 186 patients (81%). Control angiography, transcranial Doppler ultrasonography, and CT were performed routinely after surgery. Hypodense areas revealed by control CT were related to intracerebral initial hematoma, vasospasm, postoperative thrombosis, or spatula hyperpressure.

RESULTS

Clinical outcome was excellent or good (Glasgow Outcome Scale [GOS] scores of 1 or 2) in 176 patients (77%), 17 (7%) were disabled (GOS score of 3), and 37 (16%) were vegetative or dead. In patients in good condition (grades I to III) preoperatively (n = 200), 38 had an unfavorable outcome (GOS score of 2, 3, 4, or 5). The major cause of complication was postoperative thrombosis (42%). In patients in poor condition (grade IV or V) (n = 30), 27 had an unfavorable outcome. The major cause of complication was initial bleeding (66%). Vasospasm was responsible for delayed ischemic deficit in 9 patients (3.9% of the total population).

CONCLUSIONS

Systematic angiography remains by far the best means for determining the cause of a poor postoperative course.

Hemorheological and hemodynamic analysis of hypervolemic hemodilution therapy for cerebral vasospasm after aneurysmal subarachnoid hemorrhage

BACKGROUND AND PURPOSE

Hypervolemic hemodilution therapy is effective for treating neurological deficits due to cerebral vasospasm after aneurysmal subarachnoid hemorrhage (SAH). We monitored various hemorheological and hemodynamic parameters to assess the effects of hypervolemic hemodilution therapy in SAH patients with cerebral vasospasm.

METHODS

Ninety-eight patients who underwent early craniotomy for aneurysm clipping surgery after SAH were studied. Fifty-one patients (52.0%) developed symptomatic vasospasm. The hematocrit level and red blood cell aggregability were measured daily from day 1 to day 14, whereas the circulating blood volume and cerebral blood flow were measured periodically. Cardiac output and pulmonary capillary wedge pressure were also measured using a Swan-Ganz catheter.

RESULTS

The hematocrit level was decreased significantly to 29% to 32% by hypervolemic hemodilution therapy. Red blood cell aggregability increased until day 6 but was significantly reduced by therapy. Hypovolemia tended to develop after SAH. However, patients receiving hypervolemic hemodilution therapy became normovolemic to hypervolemic, with a significant increase of cardiac output and pulmonary capillary wedge pressure. At the onset of vasospasm, cerebral blood flow was significantly lower on the operated side than on the contralateral side, and it increased on both sides with therapy.

CONCLUSIONS

Patients with SAH develop hypovolemia, hemodynamic depression, and increased red blood cell aggregability. Hypervolemic hemodilution therapy decreases hematocrit level and red cell aggregability while increasing cardiac output. Improvement of hemorheological and hemodynamic parameters by this therapy can reverse neurological deterioration due to cerebral vasospasm.

The haemodynamic effect of transcranial Doppler-guided high-dose nimodipine treatment in established vasospasm after subarachnoid haemorrhage

Eleven patients (7 females) with aneurysmal subarachnoid haemorrhage (SAH) and transcranial Doppler (TCD) signs of vasospasm during prophylactic intravenous nimodipine treatment (2 mg/h) were treated with TCD-guided high-dose (4 mg/h) intravenous nimodipine. The patients were followed clinically and with serial TCD investigations. Increasing nimodipine to high-dose treatment led to a reduction of the abnormally elevated mean flow velocities (FV) in all patients. There was also a reversal of clinical signs of delayed ischaemia. In one patient, repeated computer tomographic (CT) investigations revealed a reversal of ischaemic changes. Reduction of nimodipine from 4 to 2 mg/hr resulted in a return to abnormally elevated mean FV as well as a return of clinical signs of cerebral ischaemia. The outcome was favourable in 82% of the patients and there was no mortality or vegetative survival. No patient deteriorated clinically due to vasospasm during treatment with high-dose nimodipine. The individual effect of nimodipine treatment can be monitored by the use of serial TCD investigations. TCD-guided high-dose nimodipine treatment appears to be an effective treatment in SAH patients developing vasospasm despite prophylactic standard dose treatment. The data give support for a direct vascular effect of nimodipine on cerebral vasospasm.

Intra-arterial infusion of papaverine combined with intravenous administration of high-dose nicardipine for cerebral vasospasm

The clinical effect of combination therapy with high doses of intravenous nicardipine and intra-arterial infusion of papaverine on symptomatic vasospasm after subarachnoid haemorrhage (SAH) was analysed retrospectively. In 66 of 122 patients who underwent early aneurysm surgery between 1990 and 1993, the intracranial haemodynamics were documented by transcranial Doppler (TCD) ultrasonography. 33 of these 66 patients received high dose nicardipine intravenously (Group I); the other 33 patients were not treated with calcium antagonists (Group II). Symptomatic vasospasm occurred in 6 Group I patients (18%) and in 13 (39%) in Group II patients. All 19 symptomatic patients received an intra-arterial infusion of papaverine; 15 patients (79%) responded well to this therapy and the symptoms were reversed quickly. Although the mean flow velocity (MFV) was not different between the two groups, it was reduced significantly after papverine infusion. Our retrospective analysis suggests that symptomatic vasospasm can be treated effectively with the combination of intravenous high dose nicardipine and intra-arterial infusion of papaverine, and that the correct timing of the infusions is crucial.

Nicardipine: applications in anesthesia practice

Nicardipine is the first intravenously administered dihydropyridine calcium channel blocker. Its primary physiologic actions include vasodilatation with limited effects on the inotropic and dromotropic function of the myocardium. Nicardipine has been used to control blood pressure intraoperatively in response to tracheal intubation and in the postoperative period. Various patient populations have been included such as major vascular and cardiovascular surgery. It has also been used as an agent for controlled hypotension. Preliminary experience suggests that nicardipine provides safe and effective control of perioperative blood pressure. The basic pharmacology and physiology of the most recently released calcium channel antagonist, nicardipine, is reviewed, and its applications in clinical anesthesia and interaction with other anesthetic drugs are discussed.

Protection of the brain after aneurysmal rupture

The majority of patients survive the first dangerous hours after an aneurysmal rupture. However, many subsequently succumb as a result of a variety of lethal complications. The most important of these develop as sequelae of the initial ischemia, rebleeding and the delayed onset of vasospasm. Some of these deleterious cascades can be aborted. Since the delayed complications such as vasospastic infarction can be accurately predicted, this is one of rare "strokes" that can have pharmacological pre-treatment. The natural history of rebleeding and vasospasm are described as well as their effects on blood flow, oxygen delivery and metabolism. Strategies to ameliorate acute and delayed ischemia and hypoxia are discussed. Finally, potential pharmacotherapies are detailed.

Nicardipine and treatment of cerebrovascular diseases with particular reference to hypertension-related disorders

Nicardipine is a second generation dihydropyridine-type Ca2+ antagonist with high vascular selectivity and strong cerebral and coronary vasodilatory activity. The compound is used in the treatment of hypertension, primarily in the elderly. In this review the main evidence of the cerebrovascular activity of nicardipine in preclinical studies using in vitro and in vivo models is detailed. A particular physico-chemical property of nicardipine is the almost complete protonation in acid environment. This allows its accumulation in ischemic brain regions and makes it a candidate for the treatment of cerebrovascular disorders characterised by impaired brain perfusion. The main clinical data on the use of nicardipine in cerebral ischemia and related disorders, subarachnoid haemorrhage and stroke, are also reviewed. These studies included 5940 patients affected by chronic cerebrovascular insufficiency (cerebral ischemia, cerebral atherosclerosis mainly associated with hypertension, transient ischemic attacks, sequelae of cerebral infarction, thrombosis or embolia, hypertensive encephalopathy), 1540 patients affected by sequelae of subarachnoid haemorrhage and 206 patients affected by stroke. Both preclinical studies and clinical trials have shown that nicardipine is a safe Ca2+ antagonist with powerful cerebrovascular activity. This suggests its possible use in cerebrovascular disorders in which blockade of Ca2+ channels of the L-type and/or selective cerebral vasodilatation is desirable. Further studies are necessary to establish if modulation of neuronal Ca2+ channels of the L-type by nicardipine may have a neuroprotective effect independent by the cerebrovascular activity of the compound.

Medical complications of aneurysmal subarachnoid hemorrhage: a report of the multicenter, cooperative aneurysm study. Participants of the Multicenter Cooperative Aneurysm Study

OBJECTIVES

This report examines the frequency, type, and prognostic factors of medical (nonneurologic) complications after subarachnoid hemorrhage in a large, prospective study. The influences of contemporary neurosurgical, neurological, and critical care practice on mortality and morbidity rates after aneurysmal subarachnoid hemorrhage are evaluated.

DESIGN

A study of medical complications observed in the placebo limb of a large, randomized, controlled trial of the calcium antagonist, nicardipine, after subarachnoid hemorrhage.

SETTING

Patients were recruited from 50 hospitals in 41 neurosurgical centers in the United States and Canada.

PATIENTS

A total of 457 patients with subarachnoid hemorrhage, > or = 18 yrs of age, were randomly assigned to the placebo group. All patients arrived at the participating center within 7 days (mean 1.0 +/- 1.8 [SD] days) of rupture of an angiographically documented saccular aneurysm.

MEASUREMENTS AND MAIN RESULTS

The frequency rates of symptomatic vasospasm, rebleeding, and total mortality rate after subarachnoid hemorrhage at 3-month follow-up were 46%, 7%, and 19%, respectively. The frequency of having at least one severe (life-threatening) medical complication was 40%. The proportion of deaths from medical complications was 23%. This value was comparable with the proportion of deaths attributed to the direct effects of the initial hemorrhage (19%), rebleeding (22%), and vasospasm (23%) after aneurysmal rupture. The frequency of life-threatening cardiac arrhythmias was 5%; less ominous rhythm disturbances occurred in 30% of the patients. There was an increased frequency of cardiac arrhythmias on the day of, or day after, aneurysm surgery. Pulmonary edema occurred in 23% of the patients, with a 6% occurrence rate incidence of severe pulmonary edema. There was a wide variation from center to center, with the greatest frequency on days 3 through 7. There was a nonsignificant association of pulmonary edema with the use of hypertensive hypervolemic therapy (p = .10), and a significant association with the timing of surgery (p < .05). Some degree of hepatic dysfunction was noted in 24% of patients, the majority with only mild abnormalities of hepatic enzymes with no clinical accompaniment (4% frequency of severe hepatic dysfunction). Thrombocytopenia occurred in 4% of patients, usually in the setting of sepsis. Renal dysfunction was reported in 7% of the patients, with 15% of that figure deemed to be of life-threatening severity. There was an association (p = .001) with antibiotic therapy.

CONCLUSIONS

Potentially preventable medical complications after ruptured cerebral aneurysm add to the total mortality rate of patients, and may increase length of hospital stay in the critical care setting. The proportion of deaths after subarachnoid hemorrhage from medical complications equals those deaths from either direct effects, rebleeding, or vasospasm individually. Pulmonary complications are the most common nonneurologic cause of death. Cardiac arrhythmia, although frequent, was not associated with significant mortality. The frequency of cardiac arrhythmia and pulmonary edema increased on the day of, or day after, aneurysm surgery. Renal and hepatic dysfunction, and blood dyscrasias, were also observed, underscoring the need for meticulous monitoring for metabolic and hematologic derangements.

Phase II trial of tirilazad in aneurysmal subarachnoid hemorrhage. A report of the Cooperative Aneurysm Study

Tirilazad mesylate, a 21-aminosteroid free-radical scavenger, has been shown to ameliorate cerebral vasospasm and reduce infarct size in animal models of subarachnoid hemorrhage (SAH) and focal cerebral ischemia. In preparation for performing large-scale clinical trials in humans with aneurysmal SAH, the safety of varying doses of tirilazad was tested in a randomized, double-blind, vehicle-controlled, sequential dose-escalation study at 12 Canadian neurosurgical centers. Two hundred forty-five patients with an aneurysmal SAH documented by angiography were enrolled in the study sequentially within 72 hours of hemorrhage. The patients were assigned to one of three dosage tiers: receiving 0.6 mg/kg, 2 mg/kg, or 6 mg/kg tirilazad or vehicle per day intravenously in divided doses through Day 10 following the SAH. All patients also received oral nimodipine. No serious side effects of tirilazad treatment were identified at any of the three doses, despite close monitoring of hepatic and cardiac toxicity. A trend toward improvement in overall 3-month patient outcome was seen in the 2 mg/kg per day tirilazad-treated group compared to the outcomes in the vehicle-treated groups. We conclude that tirilazad mesylate is safe in SAH patients at doses up to 6 mg/kg per day for up to 10 days and is a promising drug for the treatment of patients with aneurysmal SAH.

[Controlled hypertension and cerebral protection]

Among the techniques of cerebral protection, the use of controlled arterial hypertension is based on the following arguments: 1) Cerebral ischaemia is the final common pathway of any insult to the brain, particularly through secondary lesions. Causes of secondary cerebral lesions include pressure under the brain retractors, temporary clipping, arterial hypotension, hypoxaemia, anaemia and hypercapnia. 2) In the brain, the critical lower value for cerebral blood flow is around 25 mL.100g-1.min-1, under which two types of ischaemic areas can be defined: the penlucida type where cerebral function is abolished, without permanent cerebral lesion and the penumbra type where cerebral tissue recovers only if flow is rapidly restored. In the latter case the duration of ischaemia is very important. 3) Cerebral blood flow is maintained stable within a large range of variations of mean arterial pressure through the autoregulation mechanisms, which is based on vasomotricity of the cerebral circulation, which implies major variations in cerebral blood volume. However, autoregulation needs several dozens of seconds to be achieved. Therefore, sudden variations in mean arterial pressure are associated with short lasting but major variations in cerebral blood volume. 4) In case of increased intracranial pressure, a decrease in cerebral perfusion pressure causes cerebral vasodilation through the autoregulation mechanism, with an increase in cerebral blood volume which will, in turn, increase intracranial pressure and thus decrease cerebral perfusion pressure, and so on. This is the vasodilatory cascade. The therapeutical increase in mean arterial pressure will correct this phenomenon and decrease intracranial pressure. This is called the vasoconstrictive cascade.(ABSTRACT TRUNCATED AT 250 WORDS)

[Pharmacologic brain protection: specific agents]

Dysfunctional sodium influx is the first step in the ischaemic cascade. It has been recently demonstrated that reducing ionic flux through voltagegated Na channels shortens the NMDA receptor activity of cultured hippocampal slices in which oxidative phosphorylation and glycolysis have been blocked. The implication of this finding is that blocking initial events in the ischaemic cascade, events which do not directly cause neuronal damage, will reduce the damage done by downstream events. It also seems intuitively reasonable to suppose that truncating initial steps of the ischaemic cascade, as distinct from blocking glutamate receptors and scavening free radicals, will reduce the probability of interfering with endogenous mechanisms of repair. Clinically useful, substantive, prophylactic, pharmacological cerebral protection will come from drugs that work upstream. And for pharmacological protection that can only be initiated subsequent to an ischaemic event, the more we learn about endogenous repair, or genetic pharmacology, the closer we will come to maximizing the benefits and minimizing the costs of downstream intervention.

Subarachnoid hemorrhage: an update of pathogenesis, diagnosis and management

Subarachnoid hemorrhage (SAH) remains a devastating neurological disorder, which most commonly develops after rupture of an intracranial aneurysm. Advances have occurred in the areas of epidemiology, diagnostic imaging, medical management and surgical intervention, related to aneurysmal SAH. Interested physicians must become aware of these and other advances to diagnose and manage this potentially lethal disorder more effectively. This review provides information about the pathogenesis and complications of aneurysmal SAH and an update of new and evolving treatment modalities to provide an in-depth overview for the clinician and researcher involved in this rapidly evolving field.

A randomized trial of two doses of nicardipine in aneurysmal subarachnoid hemorrhage. A report of the Cooperative Aneurysm Study

High-dose intravenous nicardipine has been shown to reduce the incidence of angiographic and symptomatic vasospasm in patients with aneurysmal subarachnoid hemorrhage (SAH), but treatment may be complicated by side effects, including hypotension or pulmonary edema/azotemia. From August, 1989, to January, 1991, 365 patients at 21 neurosurgical centers were entered into a randomized double-blind trial comparing high-dose (0.15 mg/kg/hr) nicardipine with a 50% lower dose (0.075 mg/kg/hr) administered by continuous intravenous infusion for up to 14 days following SAH. Patients in all neurological grades were eligible for the study. During the study period, 184 patients were randomly assigned to receive high-dose nicardipine and 181 to receive the low dose. There were no significant differences in patient age, admission neurological condition, or amount and distribution of blood clot on initial computerized tomography scan. Patients in the high-dose group received a significantly smaller proportion of the planned dose than those in the low-dose group (80% +/- 0.2% vs. 86% +/- 0.2%, p < 0.05), largely because of premature treatment termination after adverse medical events. The incidence of symptomatic vasospasm was 31% in both groups, and the overall 3-month outcomes were nearly identical. These data suggest that, from a clinical standpoint, the results of high-dose and low-dose nicardipine treatment are virtually equivalent, but administration of low-dose nicardipine is attended by fewer side effects.

Effects of prophylactic intrathecal administrations of nicardipine on vasospasm in patients with severe aneurysmal subarachnoid haemorrhage

Calcium antagonists are currently most widely used for chronic cerebral vasospasm after aneurysmal subarachnoid haemorrhage (SAH). However, the vasodilatory effects of systemically administered calcium antagonists can be limited secondary to hypotension. We previously compared intrathecal and intravenous routes of administration of nicardipine. Intrathecal administration of nicardipine significantly dilated spastic basilar arteries on day 7 in a two-haemorrhage canine model of vasospasm. In the present communication, the effects of prophylactic, serial administration of intrathecal nicardipine on vasospasm was examined in 50 patients. Patients were classified as Fisher SAH group 3 and all had their aneurysms clipped within 3 days of SAH. Following placement of a cisternal drain, 2 mg of nicardipine was injected, three times each day for an average of 10 days. The control group consisted of 91 similar patients with cisternal drainage not treated with nicardipine. Intrathecal administration of nicardipine decreased the incidence of symptomatic vasospasm by 26%, angiographic vasospasm by 20% and increased good clinical outcome at one month after the haemorrhage by 15%. Postoperative angiograms revealed that patients in the nicardipine group showed less vasospasm of major cerebral arteries, near the tip of a drain in the basal cistern, but vasospasm in the A2 and M2 segments was not decreased. Radio-isotope cisternography suggested that nicardipine might not reach the subarachnoid space around A2 and M2 segments. Nine patients complained of headache probably secondary to nicardipine induced vasodilation. Two patients suffered from meningitis, both were successfully treated. Intrathecal administration nicardipine appears to be effective in the treatment of vasospasm, but side effects were significant.

[Anesthesia in surgery for intracranial aneurysms]

The two major neurological complications of subarachnoid haemorrhage (SAH) due to an intracranial aneurysm are rebleeding and delayed cerebral ischaemia related to cerebral vasospasm. The best way to prevent rebleeding is early surgery. Even when surgery is performed within the first 72 hours posthaemorrhage, the risk of cerebral ischaemia due to vasospasm is high. Conventional medical treatment of cerebral vasospasm includes haemodilution, hypervolaemia and increase of arterial blood pressure. Haemodilution is of limited value as the patients suffering from SAH have usually a low haematocrit. The effectiveness of hypervolaemia is controversial and it may worsen cerebral and pulmonary oedema. Systemic hypertension is an effective therapy of vasospasm, but which can only be used once the aneurysm is controlled. Nimodipine and nicardipine, two calcium antagonists, have a beneficial effect on neurologic outcome following SAH. Today, it is still debated whether the beneficial effect of nimodipine results from the vascular effect of the drug or from a direct cerebral cytoprotective mechanism. Early surgery implies that surgeons operate on brains in acute inflammatory state. Thus, it is mandatory to use peroperative techniques improving cerebral exposure. These techniques include infusion of mannitol, lumbar cerebrospinal fluid (CSF) drainage, administration of anaesthetic agents known to decrease cerebral blood flow (CBF) and hypocapnia. Usually, the effect of CSF drainage is very effective and sufficient by itself. The second objective in the peroperative period is to avoid ischaemia. In areas with decreased flow distal to vasospasm, autoregulation is impaired and CBF is directly dependent on cerebral perfusion pressure. Furthermore, the safe practice of transient clipping of vessels supplying the aneurysm has dramatically reduced the indications of controlled hypotension. During temporary clipping, some authors recommend a pharmacological brain protection using barbiturates, etomidate or propofol, but this practice has not been validated by randomized studies. However, it is generally agreed that the arterial pressure should be increased during temporary clipping to improve collateral blood flow and to maintain it after the aneurysm has been secured. To conclude, together with lumbar CSF drainage and transient clipping, the anaesthetic management of the patients should include: maintenance of the arterial blood pressure close to its preoperative level, maintenance of PaCO2 between 30 and 35 mmHg and of normovolaemia through replacement of fluid and blood losses. After completion of surgery, recovery from anaesthesia should be rapid to allow fast diagnosis of neurological complications. The monitoring of the status of consciousness is the key of the diagnosis of early postoperative complications.

Plasma glucose levels and outcome after aneurysmal subarachnoid hemorrhage

Plasma glucose levels were studied in 616 patients admitted within 72 hours after subarachnoid hemorrhage (SAH). Glucose levels measured at admission showed a statistically significant association with Glasgow Coma Scale scores, Botterell grade, deposition of blood on computerized tomography (CT) scans, and level of consciousness at admission. Elevated glucose levels at admission predicted poor outcome. A good recovery, as assessed by the Glasgow Outcome Scale at 3 months, occurred in 70.2% of patients with normal glucose levels (< or = 120 mg/dl) and in 53.7% of patients with hyperglycemia (> 120 mg/dl) (p = 0.002). The death rates for these two groups were 6.7% and 19.9%, respectively (p = 0.001). The association was still maintained after adjusting for age (> or < or = 50 years) and thickness of clot on CT scans (thin or thick) in the subset of patients who were alert/drowsy at admission. Increased mean glucose levels between Days 3 and 7 also predicted a worse outcome; good recovery was observed in 132 (73.7%) of 179 patients who had normal mean glucose levels (< or = 120 mg/dl) and 160 (49.7%) of 322 who had elevated mean glucose levels (> 120 mg/dl) (p < 0.0001). Death occurred in 6.7% and 20.8% of the two groups, respectively (p < 0.0001). It is concluded that admission plasma glucose levels can serve as an objective prognostic indicator after SAH. Elevated glucose levels during the 1st week after SAH also predict a poor outcome. However, a causal link between hyperglycemia and outcome after delayed cerebral ischemia, although suggested by experimental data, cannot be established on the basis of this study.

A randomized trial of nicardipine in subarachnoid hemorrhage: angiographic and transcranial Doppler ultrasound results. A report of the Cooperative Aneurysm Study

Calcium antagonist drugs were proposed for use in patients with recent aneurysmal subarachnoid hemorrhage (SAH) because of their ability to block the effects of a wide variety of vasoconstrictor substances on cerebral arteries in vitro. It was suggested that these agents might, therefore, be useful in ameliorating cerebral vasospasm and its ischemic consequences which frequently complicate SAH. This hypothesis was tested in an arm of a randomized double-blind placebo-controlled trial of high-dose intravenous nicardipine in patients with recently ruptured aneurysms. Participating investigators were required to send selected copies of all admission and follow-up angiograms obtained between Days 7 and 11 following hemorrhage (the peak period of risk for vasospasm) to the Central Registry of the Cooperative Aneurysm Study for blinded interpretation and review for the presence and severity of angiographic vasospasm. In centers with transcranial Doppler ultrasound (TCD) capabilities, middle cerebral artery (MCA) mean flow velocities were measured and recorded. Angiograms obtained between Days 7 and 11 were available for 103 (23%) of 449 patients receiving nicardipine and 121 (26%) of 457 receiving placebo. There was a balance of prognostic factors for vasospasm between the groups. Fifty-one percent of placebo-treated patients had moderate or severe vasospasm on "Day 7-11 angiograms" compared to 33% of nicardipine-treated patients. This difference is statistically significant (p < 0.01). Sixty-seven (49%) of 137 placebo-treated patients examined with TCD between Days 7 and 11 had mean MCA flow velocities exceeding 120 cm/sec compared to 26 (23%) of 112 nicardipine-treated patients (significant difference, p < 0.001). These data suggest that high-dose intravenous nicardipine reduces the incidence and severity of delayed cerebral arterial narrowing in patients following aneurysmal SAH.