Human pial vascular reactions to intravenous Nimodipine-infusion during EC-IC bypass surgery

Patients With

This study compared the roles of extraparenchymal autonomic nervous system (ANS) control of cerebral blood flow (CBF) versus intraparenchymal cerebrovascular autoregulation in 487 patients with aneurysmal subarachnoid hemorrhage (SAH) and 413 patients with traumatic brain injury (TBI). Vasomotion intensity of extraparenchymal and intraparenchymal vessels were quantified as the amplitude of oscillations of arterial blood pressure (ABP) and intracranial pressure (ICP) in the very low frequency range of 0.02-0.07 Hz, or periods of 55-15 sec, computed with a bandpass filter. A version of the pressure reactivity index (PRx-55-15) was computed as the correlation of the filtered waveforms, ABP-55-15 and ICP-55-15. Since ABP-55-15 is measured in the radial artery, any influence of cerebral factors must be mediated by the ANS. ICP-55-15 is measured in the brain and is influenced by intraparenchymal chemical and metabolic factors in addition to the ANS. Patient outcome was assessed using the Extended Glasgow Outcome Score (GOSe). Ten-day mean cerebral perfusion pressure (CPP) was negatively correlated with GOSe in the TBI cohort (R = -0.13, p = 0.01) but positively correlated with GOSe in the SAH cohort, (R = 0.32, p < 0.00001), indicating a much greater dependence on ANS support in the form of elevated CPP in SAH. The optimal CPP range for TBI was 60-70 mmHg, but for SAH it was 110-120 mmHg. The percentage of monitoring time with PRx-55-15 < 0.8, indicating very pressure-active cerebral vessels that resist ANS influence via systemic ABP, is positively correlated with GOSe in the TBI cohort (R = 0.14, p = 0.003), but negatively correlated with GOSe in the SAH cohort (R = -0.10, p = 0.004). The TBI cohort optimal PRx-55-15 for patient outcome was -1.0, while the SAH optimum was 0.3. For the TBI cohort, the correlation of ABP-55-15 amplitude with 10-day mean ICP-55-15 amplitude was 0.29. For the SAH cohort the correlation was 0.51, which is stronger (p = 0.0001). The TBI cohort had a median GOSe of 5 (interquartile range [IQR] 3-7), while SAH had a median of 3 (IQR 3-5), which is worse (p < 0.00001). The higher optimal CPP in patients with SAH, more passive optimal pressure reactivity, and greater dependence of cerebral on systemic vasomotion indicate that they require more active support by the ANS and systemic circulation for CBF than patients with TBI. CBF in patients with TBI is more reliant on cerebrovascular autoregulation based on metabolic demand. This appears to be deficient following SAH, making the heightened ANS support necessary. Although this support is beneficial, it does not fully compensate for the loss of cerebrovascular autoregulation, as reflected in the problems in the SAH cohort with delayed cerebral ischemia and poor outcome.

Cerebral Autoregulation in Subarachnoid Hemorrhage

Subarachnoid hemorrhage (SAH) is a devastating stroke subtype with a high rate of mortality and morbidity. The poor clinical outcome can be attributed to the biphasic course of the disease: even if the patient survives the initial bleeding emergency, delayed cerebral ischemia (DCI) frequently follows within 2 weeks time and levies additional serious brain injury. Current therapeutic interventions do not specifically target the microvascular dysfunction underlying the ischemic event and as a consequence, provide only modest improvement in clinical outcome. SAH perturbs an extensive number of microvascular processes, including the “automated” control of cerebral perfusion, termed “cerebral autoregulation.” Recent evidence suggests that disrupted cerebral autoregulation is an important aspect of SAH-induced brain injury. This review presents the key clinical aspects of cerebral autoregulation and its disruption in SAH: it provides a mechanistic overview of cerebral autoregulation, describes current clinical methods for measuring autoregulation in SAH patients and reviews current and emerging therapeutic options for SAH patients. Recent advancements should fuel optimism that microvascular dysfunction and cerebral autoregulation can be rectified in SAH patients.

Outcome of Oral and Intra-arterial Nimodipine Administration After Aneurysmal Subarachnoid Haemorrhage - A Single-centre Study

BACKGROUND

Oral nimodipine is administered to improve clinical outcome in patients with aneurysmal subarachnoid hemorrhage (aSAH). In this study, clinical outcome in patients with and without oral nimodipine administration was assessed.

MATERIALS AND METHODS

A total of 105 patients did not receive oral nimodipine but did receive intra-arterial nimodipine in the occurrence of hemodynamically relevant vasospasm after aSAH, whereas 74 patients received applications of both. Demographic/radiological details and clinical presentation were abstracted from the case records.

RESULTS

Patient baseline characteristics were comparable, a predominance of endovascular coiling was shown in cohort 2 (p=0.0135). Severity of initial aSAH and clinical status at admission (Hunt and Hess) was significantly higher in those receiving oral nimodipine. Incidence of angiographic vasospasm was significantly higher in patients not treated with oral nimodipine (p=0.0305); a significantly better outcome measured by the National Institute of Health Stroke Scale (p=0.0213), was noted in those receiving oral nimodipine.

CONCLUSION

Oral nimodipine administration improved clinical outcome of patients after aSAH and should be administered routinely for such patients.

Effects of intrathecal administration of nicardipine and nifedipine on chronic cerebral vasospasm in dogs

Chronic cerebral vasospasm after subarachnoid haemorrhage (SAH) responds poorly to systemic administration of dihydropyridine calcium antagonists. However, the spastic arteries can be dilated by the topical (intrathecal) administration of the drugs. We examined by angiography the spasmolytic effects of intrathecal (cisternal) administration of nicardipine (0.1 mg 1 ml ) or nifedipine (0.1 mg 1 ml ) on day 7 of SAH made by the two-haemorrhage model in dogs. Both drugs dilated the spastic basilar artery from 15 min till 4 hours after the drug administration. The increase in the diameter of the basilar artery between 1 and 3 hours was statistically significant in both groups. Intrathecal administration of nicardipine which is water soluble, may be useful in the treatment of chronic cerebral vasospasm in patients.

Angiographic vasospasm in a contemporary series of patients with aneurysmal subarachnoid haemorrhage

Over the last decade there have been significant changes in the management of patients with aneurysmal subarachnoid haemorrhage (SAH). Many of these changes, such as haemodilutional, hypervolaemic, hypertensive therapy and the use of calcium channel blockers, have been directed at the prevention and treatment of vasospasm. The angiograms of a contemporary series of 56 consecutive surgically treated patients with aneurysmal SAH were examined to compare angiographic vasospasm with that seen in historical studies. The time course of angiographic vasospasm was found to be broadly similar to that reported in previous studies, with onset after day 3 following SAH, maximal narrowing during the second week, and resolution after day 16. The times of peak narrowing and resolution were slightly earlier in previous studies. 30% of patients had clinical vasospasm (delayed neurological deficit for which other causes had been excluded), and these patients had a trend to more severe angiographic narrowing than those without clinical vasospasm, particularly in the second week following SAH. 44 angiograms were performed between days 1-3 post SAH and repeated between days 4-16. 95% of these showed arterial narrowing at the second angiogram. Patients not achieving an independent outcome tended to have had both more clinical vasospasm and more severe angiographic spasm than those achieving independence. It is concluded that angiographic vasospasm remains a common occurrence in the modern era, and continues to be associated with clinical events and a poor outcome.

Cerebral vasospasm and calcium channel blockade. Nimodipine treatment in patients with aneurysmal subarachnoid hemorrhage

In patients with aneurysmal subarachnoid hemorrhage (SAH), delayed ischemic cerebral dysfunction (DID or symptomatic vasospasm) with subsequent fixed neurological dysfunction (FND) is a frequent and most feared complication induced by the hemorrhage. Aneurysm operation during the acute stage with intraoperative evacuation of bloodcontaminated cerebrospinal fluid (CSF) from the basal cisterns and subarachnoid spaces has reduced this complication. Nevertheless despite early operation, DID with FND occurs in 13-20% or more. In a series of 100 individuals with a ruptured supratentorial aneurysm, who were subjected to aneurysm operation in the acute stage and who subsequently received intravenous treatment with the calcium channel blocker nimodipine, the occurrence of DID with FND was reduced to 5%.

Determination of nimodipine in human plasma by a sensitive and selective liquid chromatography–tandem mass spectrometry method

A sensitive and highly selective liquid chromatography-tandem mass spectrometry (LC-MS-MS) method was developed to determine nimodipine in human plasma. The analyte and internal standard nitrendipine were extracted from plasma samples by n-hexane-dichloromethane-isopropanol (300:150:4, v/v/v), and chromatographed on a C(18) column. The mobile phase consisted of methanol-water-formic acid (80:20:1, v/v/v). Detection was performed on a triple quadrupole tandem mass spectrometer by selected reaction monitoring (SRM) mode via atmospheric pressure chemical ionization (APCI) source. The method has a limit of quantification of 0.24 ng/ml. The linear calibration curves were obtained in the concentration range of 0.24-80 ng/ml. The intra- and inter-day precisions were lower than 4.4% in terms of relative standard deviation (R.S.D.), and the accuracy ranged from 0.0 to 5.8% in terms of relative error (RE). This validated method was successfully applied for the evaluation of pharmacokinetic profiles of nimodipine tablets administered to 18 healthy volunteers.

Acute protective effect of nimodipine and dimethyl sulfoxide against hypoxic and ischemic damage in brain slices

Nimodipine and dimethyl sulfoxide (DMSO) were tested (alone and in combination) regarding their ability to increase hypoxic tolerance of brain slices under 'hypoxic' (deprivation of oxygen) or 'ischemic' (hypoxia+withdrawal of glucose) conditions. Direct current (DC) and evoked potentials were recorded in the CA1 region of hippocampal slices of adult guinea pigs. After induction of hypoxia or ischemia, the latency of anoxic terminal negativity (ATN) of the DC potential was determined during superfusion with artificial cerebrospinal fluid alone (aCSF), and during superfusion with aCSF containing DMSO [0.1% (14.1 mmol/l) and 0.4% (56.3 mmol/l)] with the addition of nimodipine (40 micromol/l). Latencies of ATN with first hypoxia were 6.7+/-3.7 min in the control group, 9. 3+/-4.2 min in the 0.4% DMSO group and 12.3+/-5.5 min (P=0.007) in the nimodipine/0.4% DMSO group. Latencies of ATN with first ischemia were 2.9+/-2 min in the control group, 4.1+/-1.6 min in the 0.1% DMSO group, 7.1+/-3.9 min in the 0.4% DMSO group (P=0.006), 5.3+/-1. 5 min in the nimodipine/0.1% DMSO group and 7.6+/-3 min (P<0.001) in the nimodipine/0.4% DMSO group. DMSO (0.4%), either alone or in combination with nimodipine, increase the latency of the ATN after acute onset of hypoxia and ischemia.

Efficacy and safety of nimodipine in subcortical vascular dementia: a subgroup analysis of the Scandinavian Multi-Infarct Dementia Trial

In Western countries, vascular dementia (VaD) is the most common form of cognitive deterioration after Alzheimer's disease. Therapeutic trials in VaD have so far failed to yield satisfactory results. One explanation of this failure may be the etiological and clinical heterogeneity of the included patients. Patients with subcortical VaD, defined on a clinical and radiological basis, may constitute a more homogeneous group. Thus, we conducted a post-hoc subgroup analysis of the Scandinavian Multi-Infarct Dementia Trial that evaluated the efficacy and safety of oral nimodipine administered for 6 months in 259 patients. The original patients sample was divided on the basis of head CT in those with subcortical VaD (n=92, 45 nimodipine, 47 placebo) and those with multi-infarct dementia (n=167, 83 nimodipine, 84 placebo). While in the total trial population a treatment effect could not be proved, in this subgroup analysis, the subcortical VaD patients treated with nimodipine performed better on the majority of neuropsychological tests and functional scales in comparison with patients on placebo. No trend could be evidenced in the multi-infarct dementia patients. Treatment efficacy was in particular suggested for the Zahlen-Verbindungs-Test, Fuld-Object-Memory Evaluation, Word Fluency, and for the Instrumental Activities of Daily Living scale. The results did not reach statistical significance in this small sample. Our study preliminarily indicates that nimodipine could be effective in patients with small vessel subcortical VaD and supports the rationale for a further controlled and adequately powered trial to test nimodipine in patients with subcortical VaD.

The Scandinavian Multi-Infarct Dementia Trial: a double-blind, placebo-controlled trial on nimodipine in multi-infarct dementia

Vascular dementia is a major cause of mental and physical disability in Western countries. Treatment of vascular dementia is currently based on the recognition and control of vascular risk factors, while specific drugs have not been approved yet. The aim of the present multinational, double-blind, placebo-controlled study was to evaluate the safety and efficacy of nimodipine administered for as long as 26 weeks in improving cognition or slowing cognitive deterioration in patients defined as having multi-infarct dementia (DSM-III-R criteria). Two hundred and fifty-nine patients were included (128 nimodipine, 131 placebo), and 251 were available for the intention-to-treat analysis. No significant difference between drug-treated and placebo patients was noted on the Gottfries-Brâne-Steen scale score (primary efficacy criterion), the remaining neuropsychological tests (Zahlen-Verbindungs-Test, Fuld-Object-Memory Evaluation, Word Fluency Test, Digit Span, Mini-Mental State Examination), and the functional scales (index of Activity of Daily Living, Instrumental Activity of Daily Living, Rapid Disability Scale, Clinical Dementia Rating), although the majority of changes were in favor of the active drug group. A lower incidence of cerebrovascular and cardiac events was observed in the nimodipine-treated patients in comparison with the placebo group. This study failed to show a significant effect of nimodipine on cognitive, social or global assessments in patients defined as affected by multi-infarct dementia according to the DSM-III-R criteria. A post-hoc analysis (presented in an accompanying paper) suggests that nimodipine may have a favorable effect in the subgroup of patients defined as affected by subcortical (small vessel) vascular dementia.

Calcium channels in cerebral arteries

Electrophysiological evidence shows the existence of voltage-operated Ca2+ channels of the L- and, in some cases, T- and B-, type in the smooth muscle cells of major cerebral arteries and arterioles. Current intensity through L-type Ca2+ channels is higher in cerebral than in peripheral arteries, which points to a greater dependence on extracellular Ca2+ of contractile responses in cerebral arteries. The increase in cytosolic Ca2+ concentration is the key event leading both to maintenance of basal cerebrovascular tone and to contraction of cerebral arteries in response to depolarization and agonist-receptor interaction. Such an increase results from increased transmembrane influx of Ca2+ through L-type Ca2+ channels, as well as from the release of Ca2+ from intracellular Ca2+ stores. Ca2+ entry modulators (dihydropyridines, phenylalkylamines, benzothiazepines, and diphenylpiperazines) bind to allosterically coupled sites in the Ca2+ channel, thus inhibiting (Ca2+ entry blockers) or stimulating (Ca2+ entry activators) Ca2+ influx and, therefore, contractile responses of the cerebral arteries. In vivo, Ca2+ entry blockers increase pial vascular caliber and cerebral blood flow by their direct action on the cerebroarterial wall. However, such an action also takes place on several peripheral vascular beds, which leads to hypotension. Therefore, the brain cannot be considered a "privileged" organ when the vasodilatatory action of Ca2+ entry blockers is considered. Since increased cytosolic Ca2+ concentration (and, therefore, activation of Ca2+ channels) plays a crucial role in the pathogenesis of ischemic brain damage (e.g., acute stroke and subarachnoid hemorrhage), Ca2+ entry blockers could be useful cytoprotective drugs. However, with the exception of nimodipine in the management of subarachnoid hemorrhage, clinical trials have yielded results that are not so promising as one could expect from those obtained in experimental research.

Effect of nicardipine on basilar artery vasoactive responses after subarachnoid hemorrhage

The effect of the dihydropyridine calcium antagonist, nicardipine, on the vasoactive responses of the basilar artery was investigated after subarachnoid hemorrhage (SAH). Forty-five rabbits were separated into one control group and four groups receiving SAH (nine animals each). The SAH was induced by injecting 5 ml of autologous arterial blood into the cisterna magna. SAH animals were subjected to one of the following: 1) no treatment; 2) intravenous (i.v.) saline infusion (vehicle); 3) i.v. infusion of low-dose nicardipine (0.01 mg/kg/hr), or 4) i.v. infusion of high-dose nicardipine (0.15 mg/kg/hr). The i.v. infusions were started immediately after SAH and continued for 48 hours. Serotonin (5-HT) (10(-8) to 10(-5) mol/L) was used to evoke dose-dependent vasoconstriction of isolated rings of the basilar artery 2 days after SAH. Acetylcholine (ACh) (10(-8) to 10(-4)) and adenosine-triphosphate (ATP) (10(-8) to 10(-4) mol/L) were applied after maximal contraction with 5-HT, evoke a dose-dependent vasodilatation. Compared with controls, in animals subjected to SAH serotonin caused similar or slightly larger contractions; nicardipine infusion did not decrease the amount of contraction observed after SAH. ACh and ATP caused significantly less dilatation in animals submitted to SAH than in controls. After high-dose nicardipine, ACh- and ATP-induced dilatations were significantly more pronounced (57% and 68% of initial contractile tone) than in the other animals receiving SAH (36%-39% and 45%-55%, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

An in vitro comparative study of conducting vessels and penetrating arterioles after experimental subarachnoid hemorrhage in the rabbit

The reactivity of rabbit basilar artery and penetrating arteriolar microvessels was studied in vitro using an isometric-tension measurement technique and an isolated perfused arteriole preparation, respectively. Comparisons were made between reactivities of normal vessels and those obtained from animals subjected to experimental subarachnoid hemorrhage (SAH) 3 days prior to examination. Subarachnoid hemorrhage produced significant increases in basilar artery contraction in response to increasing concentrations of serotonin (5-hydroxytryptamine) (10(-9) to 10(-5) M) and prostaglandin F2 alpha (10(-9) to 10(-5) M) when compared to normal arteries. In addition, SAH attenuated the relaxing effect of acetylcholine following serotonin-induced contraction and of adenosine triphosphate after KCl-induced basilar artery contractions. In contrast to the changes observed in large arteries, cerebral microvessels did not demonstrate significant differences in spontaneous tone or in reactivity to a number of vasoactive stimuli including application of calcium, serotonin, and acetylcholine. On the other hand, small but significant changes in arteriolar responsiveness to changes in extraluminal pH and to application of KCl were noted. Findings from this study suggest that intracerebral resistance vessels of the cerebral microcirculation are not greatly affected by the presence of subarachnoid clot, in contrast to the large arteries in the basal subarachnoid space. The small changes that do occur are qualitatively different from those observed for large arteries. These findings are consistent with the observation of significant therapeutic benefit with the use of calcium channel blockers without changes in angiographically visible vasospasm in large vessels. It is likely, therefore, that calcium antagonists may act to decrease total cerebrovascular resistance at the level of the relatively unaffected microcirculation after SAH without changing large vessel diameter.

Unfavorable outcome following early surgical repair of ruptured cerebral aneurysms--a critical review of 238 patients

Among 238 consecutive patients admitted early with ruptured cerebral aneurysms, surgical repair within 48-72 hours was feasible in 200 cases. Unfavorable outcomes among the latter 200 patients are analyzed and discussed in this paper. Preoperatively, 148 patients were in Hunt and Hess grades I-III, 33 were in grade IV, and 19 in grade V. After clipping of the aneurysm, all patients received a regimen of topical intracisternal and intravenous/peroral medication with the calcium antagonist nimodipine. The overall rate of unfavorable outcomes was 25%, ie, outcome with moderate or severe deficit or lethal outcome. The reasons for unfavorable outcomes among these 49 patients were the devastating effect of the bleed (severe subarachnoid hemorrhage or additional intracerebral hemorrhage) in 31 patients (15% of the 200 patients), a surgical complication in 11 (5.5%), preoperative rebleeding in three (1.5%), delayed ischemia from vasospasm in one (0.5%), and various others in three further patients (1.5%). Unfavorable outcome occurred in 11% of patients with preoperative grades I-III, in 52% of patients with grade IV, and in 16 of 19 patients with grade V. Among the 141 patients with subarachnoid hemorrhage but not intracerebral or intraventricular hematoma, 16 made an unfavorable outcome, ie, 11% versus 56% among patients with intracerebral hematoma/intraventricular hematoma on preoperative computed tomography scan. The present data seem to speak in favor of early surgery. Since half of the patients with intracerebral hematoma and poor outcome had suffered previous warning leaks, it appears to be a continuing challenge to diagnose warning leaks before a massive hemorrhage occurs.

Long-term effects of nimodipine on cerebral infarcts and outcome after aneurysmal subarachnoid hemorrhage and surgery

A total of 213 patients with verified aneurysmal subarachnoid hemorrhage (SAH) of Grades I to III (Hunt and Hess classification) were enrolled in a double-blind placebo-controlled trial to determine the effect of intravenous nimodipine on delayed ischemic deterioration and computerized tomography (CT)-visualized infarcts after SAH and surgery. The administration of the drug or matching placebo was started immediately after the radiological diagnosis of a ruptured aneurysm had been made. Of the 213 patients enrolled in the study, 58 were operated on early (within 72 hours after the bleed: Days 0 to 3), 69 were operated on subacutely (between Days 4 and 7), and 74 had late surgery (on Day 8 or later). Eleven patients died before surgery was undertaken and one was not operated on. A follow-up examination with CT scanning, performed 1 to 3 years after the SAH (mean 1.4 years), revealed no significant differences in the overall outcome between the groups. However, nimodipine treatment was associated with a significantly lower incidence of deaths caused by delayed cerebral ischemia (p = 0.01) and significantly lower occurrence of cerebral infarcts visualized by CT scanning in the whole population (p = 0.05), especially in patients without an associated intracerebral hemorrhage on admission CT scan (p = 0.03).

The effect of nimodipine on the evolution of human cerebral infarction studied by PET

Fourteen patients were studied by positron emission tomography (PET) within 48 h of onset of a hemispheric ischemic stroke and again 7 days later. After the first set of PET scans, the patients were randomized to receive either nimodipine (n = 7) or a carrier solution (n = 7) by intravenous infusion. The infusions were maintained until the end of the second PET studies. CBF, cerebral blood volume (CBV), oxygen extraction ratio (OER), CMRO2, and CMRglc were measured each time. These metabolic and perfusion measurements were performed by standard methods. A surface map of each metabolic and perfusion measurement in the cortical mantle was generated by interpolating between the available slices. The various surface maps representing the physiological characteristics determined in the same or subsequent studies were aligned so that all data sets could be analyzed identically using an array of square regions of interest (ROIs). The functional status of each ROI was recorded at the two intervals following the cerebrovascular accident to characterize the evolution of the infarct, penumbra, and normal brain regions. We presumed the ischemic penumbra to be cortical regions in the proximity of the infarct and perfused at CBF values between 12 and 18 ml/100 g/min on the first PET scan, while densely ischemic regions had CBF of less than 12 nl/100 g/min and normally perfused brain greater than 18 ml/100 g/min. In the densely ischemic zone, CBF increased more in the nimodipine-treated group than in the carrier group. As well, in this region nimodipine reversed the decline in CMRO2 noted in the carrier group, the difference in the changes being significant. In the penumbra zone, comparable trends were noted in OER and CMRO2 but the difference in the changes between the two groups did not reach statistical significance. Changes in CMRglc and CBV were comparable between the two groups in both cortical regions.

Effects of calcium antagonists on intracerebral penetrating arterioles in rats

There is no direct information on the effect of calcium antagonists on intracerebral penetrating arterioles, which are responsible for a significant part of total cerebrovascular resistance. In a study on rats, the effects of four calcium antagonists (diltiazem, verapamil, nifedipine, and nimodipine) on isolated intracerebral penetrating arterioles with mean resting diameters (+/- standard error of the mean) of 52.3 +/- 3.0 micron were investigated. Vessel diameters were monitored in vitro by means of a video microscope dimensional analyzer under constant transmural pressure (60 mm Hg) after cannulation. Each calcium antagonist produced maximal dilation of about 50% (diltiazem 46.4% +/- 5.6%, verapamil 53.1% +/- 6.0%, nifedipine 46.9% +/- 6.1%, and nimodipine 47.1% +/- 5.4%) with varied sensitivity (median effective dose (ED50): diltiazem 1.52 X 10(-6) M, verapamil 1.08 X 10(-7) M, nifedipine 8.65 X 10(-9) M, and nimodipine 1.62 X 10(-9) M). Dilation effects persisted for a significantly longer time after washout with calcium antagonists such as diltiazem (15.5 +/- 1.8 minutes), nifedipine (19.0 +/- 3.9 minutes), and nimodipine (30.0 +/- 1.6 minutes) than after washout with adenosine (8.5 +/- 1.0 minutes). It appeared that the magnitude of vasodilation was greater and the duration of dilation after washout longer in intracerebral penetrating arterioles than that reported for pial arterioles, although sensitivity to each calcium antagonist was quite similar to that reported for larger cerebral arteries. These data provide a possible explanation for the apparent disparity between clinical efficacy and angiographically determined vessel diameter when patients with cerebral vasospasm are treated with calcium antagonists. These agents may have a greater effect on intracerebral penetrating arterioles than on angiographically visible larger arteries.

Nimodipine treatment in poor-grade aneurysm patients. Results of a multicenter double-blind placebo-controlled trial

A multicenter, randomized placebo-controlled double-blind trial of nimodipine in poor-grade aneurysm patients was carried out in 17 Canadian hospitals. Of 188 patients enrolled in the trial, 32 were excluded for protocol violations and two were excluded due to statistical considerations, leaving 154 patients for valid outcome analysis. Nimodipine treatment was associated with a significantly better outcome (p less than 0.001): 21 (29.2%) of 72 nimodipine-treated patients had a good outcome at 3 months after subarachnoid hemorrhage (SAH) compared to eight (9.8%) of 82 placebo-treated patients. Delayed ischemic deficits from vasospasm alone were significantly less frequent in the nimodipine group (p less than 0.05) with permanent deficits occurring in five nimodipine-treated patients (6.9%) and in 22 placebo-treated patients (26.8%). Improvement in the good outcome rate and reduction in delayed ischemic deficits from vasospasm alone occurred in both Grade 3 and 4 patients, with no difference between nimodipine- and placebo-treated patients being found in Grade 5 patients. Repeat angiography after Day 4 was carried out in 124 patients. There was no significant difference in the incidence of moderate or severe diffuse spasm, which was seen in 64.3% of nimodipine-treated patients and 66.2% of placebo-treated patients. The authors conclude that nimodipine treatment in poor-grade patients with SAH results in an increase in the number of good outcomes and a reduction in the incidence of delayed neurological deterioration due to vasospasm. This effect occurs by a mechanism other than prevention of large-vessel spasm as visualized on angiography.

Intraoperative use of laser Doppler in the study of cerebral microvascular circulation

Laser Doppler (LD) flowmetry has been used for evaluation of microcirculatory flow in a variety of human tissues, including skin, muscle, retina and recently the brain. In the present paper, intraoperative Laser Doppler recordings have been performed in 72 cases, in basal conditions and after stimulation. The morphology of basal recordings obtained from normal cortical areas were analyzed and three different rhythmical variations were identified; these rhythmical variations are described and explained. Several kinds of stimulation have been used: hypotensive drugs, mannitol, nimodipine, eupaverine, hypercapnia, decompressive manoeuvres and temporary occlusion of the ICA in the neck. Laser Doppler recordings obtained during and after these stimulations are reported and explained. The results have been evaluated in order to verify the reliability and the reproducibility of this technique in the study of the cerebral microvascular circulation intraoperatively.

Haemodynamic effectiveness of nimodipine on spastic brain vessels after subarachnoid haemorrhage evaluated by the transcranial Doppler method. A review of clinical studies

The authors review the literature reports and own results of a double-blind study of the effectiveness of nimodipine on prevention or treatment of spasm of cerebral arteries following subarachnoid haemorrhage (SAH). Spasm has been evaluated using the transcranial Doppler method (TCD). The patients were divided into two groups which received 2 resp. 3 mg/h nimodipine. The clinical outcome and also the incidence of spasm of both of the groups were not different, but spasm was less severe in the 3 mg/h group.

The therapeutic value of nimodipine in experimental focal cerebral ischemia. Neurological outcome and histopathological findings

Recent studies suggest that nimodipine, a potent calcium-channel antagonist that causes significant cerebrovascular dilatation, may improve neurological outcome after acute experimental permanent focal cerebral ischemia when given before or immediately after occlusion of the middle cerebral artery (MCA) in various animals. The authors describe the effect of nimodipine on cerebral ischemia in a rat model. At 1, 4, or 6 hours after occlusion of the MCA, rats were treated in a double-blind technique with either nimodipine, placebo, or saline. Neurological and neuropathological evaluation was performed at 24 hours. Neurological outcome was better in rats treated with nimodipine 1, 4, or 6 hours after occlusion (p less than 0.001, p less than 0.01, p less than 0.05 respectively), and the size of areas of infarction was statistically smaller in nimodipine-treated groups (p less than 0.01, p less than 0.01, p less than 0.05, respectively) when compared with control rats treated with saline or placebo. The best neurological outcome and the smallest area of infarction were found in nimodipine-treated rats 1 hour after occlusion. Compared with controls, the size of the periphery of the infarcted area was smaller in nimodipine-treated rats. The results show that nimodipine improves neurological outcome and decreases the size of infarction when administered up to 6 hours after ischemic insult. These results suggest a possible mechanism of action of nimodipine on the "penumbra" of the ischemic area.

Survey of clinical experience with nimodipine in patients with subarachnoid hemorrhage

The present studies show that nimodipine prevents and/or improves permanent ischemic neurological deficits in patients with subarachnoid hemorrhage. This was particularly marked in four double-blind, placebo-controlled studies in which statistically significant reductions in mortality and morbidity as consequence of cerebral vasospasm were found. The drug has been shown to increase cerebral blood flow, to reduce vasoconstriction, although not to fully prevent angiographic vasospasm, and to improve central conduction time. Nimodipine did not increase the rate of rebleeding. Its administration during anesthesia does not result in management problems. In general, nimodipine was well tolerated. Side effects were recorded mainly in open studies using the intravenous formulation and consisted mainly of decreases in blood pressure and headaches. Transient increases in liver enzymes may be due to the organic solvent. Hence, all results indicate that patients with subarachnoid hemorrhage will benefit from preventive or therapeutic nimodipine treatment.

Evaluation of the calcium-antagonist nimodipine for the prevention of vasospasm after aneurysmal subarachnoid haemorrhage. A prospective transcranial Doppler ultrasound study

70 consecutive patients admitted within four days after the first aneurysmal subarachnoid haemorrhage (SAH) were evaluated by daily transcranial Doppler ultrasound (TCD) measurement of the blood flow velocities (BFVs) of both middle cerebral arteries (MCAs) and by daily recordings of their clinical grade (Hunt and Hess). Patients with no or only little subarachnoid blood in the first CT after admission were classified as low-risk for the development of symptomatic vasospasm (VSP), and patients with big subarachnoid clots or thick layers of subarachnoid blood were graded as high-risk patients for symptomatic VSP. The first series of 33 patients received no nimodipine whereas the second series of 37 patients were treated with nimodipine 2 mg/h intravenously, starting within 24 hours after the SAH in the majority of patients. 7-14 days postoperatively, the intravenous dose was changed to oral nimodipine 60 mg/q4h for one week and then discontinued. A mean BFV curve of the side with the higher flow velocities correlated with the mean clinical status (Hunt and Hess) was calculated by computer analysis for the patients treated without nimodipine and for those receiving nimodipine in each risk group. The mean BFV curves of the same risk groups were compared in order to evaluate the effect of nimodipine for the prevention of vasospasm following SAH. The delayed neurological deficits (DIND) and the functional outcome six months after the SAH were recorded in each group and compared. Nimodipine given within four days after the SAH did not prevent vasospasm evaluated by TCD, but it significantly reduced the severity of the vasoconstriction, especially in high-risk patients. It reduced significantly the incidence of DIND in high-risk patients and improved their functional outcome. Although nimodipine may have a reduced efficacy in preventing vasospasm after early operation of high-risk patients, it probably protects the brain by increasing its tolerance to focal ischaemia.

Cerebrovascular and metabolic changes during the delayed vasospasm following experimental subarachnoid hemorrhage in baboons, and treatment with a calcium antagonist

A model has been designed in baboons for simulating the clinical situation during the late phase of vasospasm in patients with subarachnoid hemorrhage (SAH). A total amount of 14-33 ml autologous blood was injected into the cisternal system on 3 occasions in the course of 4 days. Neurological symptoms were seen, and the mortality rate was 29%. Angiography 3 days after the last injection showed arterial vasoconstriction amounting to 23% in the vertebro-basilar system, and 11% (right) and 18% (left) in the carotid system. Cerebral blood flow (CBF) measured by the intra-arterial 133Xe technique and the cerebral metabolic rate of oxygen (CMRO2) were reduced by 18% and 11%, respectively. The hypercapnic CBF response was significantly impaired, from a mean of 3.90 ml/100 g/min to 1.72 ml/100 g/min of flow increase for each mm Hg elevation of paCO2. Autoregulation, tested by administration of angiotensin II, was also significantly affected as evidenced by a pressure-dependent increment of CBF during hypertension in 5 out of 7 animals tested. The impaired autoregulation was reflected in the autoregulatory index, which in the whole group increased from 0.06 ml/100 g/min for each mm Hg increase in MABP in the pre-SAH animals to 0.29 ml/100 g/min per mm Hg post-SAH. Treatment with the calcium antagonist, nimodipine (0.5 microgram/kg/min i.v. during 45 min), enhanced CBF significantly by 17% before experimental SAH, whereas after SAH the effect was slight and did not reach statistical significance; CMRO2 was not significantly affected in either group. Intravenous nimodipine combined with hypertension resulted in a marked increase in the autoregulatory index to 1.58 ml/100 g/min per mm Hg in pre-SAH animals and a less pronounced increment to 0.58 ml/100 g/min per mm Hg following experimental SAH. The beneficial effect of nimodipine reported in SAH patients is therefore, in view of our findings, more likely due primarily to a protective mechanism at the cellular level than to an influence on the vascular bed.

Influence of nimodipine and nifedipine on intrapulmonary shunting--a comparison to other vasoactive drugs

This study was assigned to investigate the influence of calcium channel blockers (nimodipine and nifedipine) in comparison to other vasoactive drugs (nitroglycerin, dopamine) on pulmonary shunting (Qs/Qt). Fifty anesthetised patients scheduled for aortocoronary bypass operation were randomly allocated to 5 groups receiving one of the following drugs: nimodipine 1.0 microgram X kg-1 X min-1; nifedipine 0.7 microgram X kg-1 X min-1; nitroglycerin (TNG) 0.5 microgram X kg-1 X min-1; dopamine; micrograms X kg-1 X min-1; placebo (0.9% NaCl). Nimodipine as well as nifedipine led to a significant increase in cardiac output (+44%; +39%), pulmonary vascular resistance simultaneously decreased (-25%; -28%). PaO2 increased significantly (+16%; +13%), too, whereas Qs/Qt remained almost unchanged. In contrast, the increase in cardiac output induced by dopamine (+27%) was accompanied by a significant increase in shunting (+34%). TNG application did not alter Qs/Qt, but pulmonary artery pressure (PAP) decreased markedly (-19%).

The effects of verapamil and ethanol on body temperature and motor coordination

Male, adult mice of the Binghamton heterogeneous stock received one of two doses of ethanol (1.0 g/kg or 2.0 g/kg in saline) alone or in combination with the calcium (Ca2+) slow channel blocker, verapamil (5.45 mg/kg in 25% v/v ethanol in saline). Hypothermic responses and motor incoordination were assessed in terms of rectal temperatures and rotorod activity both 20 and 60 min after drug administration. Verapamil alone did not affect body temperature, but it potentiated ethanol-induced hypothermia at both post-administration test times. Both verapamil and ethanol impaired muscular coordination and these effects were additive at the two observation periods. Verapamil did not affect ethanol blood levels from 10 to 80 min after administration of the drugs. Since motor impairment was observed when verapamil was administered with only its ethanol vehicle, this suggests a powerful interactive effect between the two drugs.

Prevention of vasospasm in subarachnoid haemorrhage. A controlled study with nimodipine

A prospective randomized double blind study was conducted in 70 patients suffering from subarachnoid haemorrhage, due to aneurysm rupture, to determine if the use of nimodipine reduces the severity of ischaemic deficits secondary to vasospasm. At the end of the study, two patients had severe deficit or died in the treated group, while 10 had a bad outcome in the placebo group. Angiographic vasospasm was not significantly different in its frequency or its severity between the two groups. However, the association of extensive and diffuse vasospasm was less frequent in the nimodipine group. This study confirms the effectiveness of Nimodipine in reducing the occurrence of neurological deficit due to vasospasm, even if this action is not observed in all cases.

Effect of topical nimodipine versus its ethanol-containing vehicle on cat pial arteries

Nimodipine and its solvent containing ethanol were tested in a randomized in vivo study by local administration to the outer vessel wall surface of pial arteries and veins in 15 anesthetized cats. Reactions were studied through a cranial window. Diameter variations of 90 arterial and 78 venous vessel segments were continuously analyzed using a multichannel videoangiometer. The solvent alone caused minor though statistically significant (p less than 0.001) 7.6% dilatation, 8% in small and 7% in large arteries, which returned to their resting state after stopping treatment. 2.4 X 10(-5) M nimodipine plus solvent induced a 21% pial arterial dilatation (p less than 0.001), 26% in small and 17% in large arteries; dilatation induced by nimodipine plus solvent was significantly greater than dilatation by the solvent alone (p less than 0.001). After ceasing topical administration, arteries remained dilated by some 5%. Pial veins exhibited only minor reaction, i.e. a 6% (statistical n.s.) dilatation of large veins during nimodipine, and an 8% dilatation of small veins 20 minutes after stopping nimodipine. During solvent-administration rCBF, as estimated with the hydrogen clearance technique, remained unchanged. It is concluded that the dilatatory effect of the investigated compound on pial arteries is predominantly due to nimodipine.

Nimodipine and early aneurysm operation in good condition SAH patients

A prospective open multicenter study on the preventive effect of nimodipine on symptomatic vascular spasm was performed in 120 (consecutive) patients with aneurysmal subarachnoid haemorrhage (SAH). All patients underwent early surgery (i.e. within 72 hours post SAH) and were in neurological grades I-III in Hunt and Hess. Grade IV and V as well as patients with significant intracerebral haematoma are not included. On preoperative CT, SAH was mild in 28 cases, moderate in 56 and severe in 36 cases. 25 patients (21%) were in grade I, 63 patients (53%) in grade II and 32 patients (26%) in grade III. The ruptured aneurysm was located on the anterior cerebral artery complex in 57 patients, on the internal carotid artery complex in 35, on the middle cerebral artery in 24 patients and on the basilar artery in 4 patients. After occlusion of the ruptured aneurysm, the lipophilic calcium channel blocker nimodipine was administered in the following manner: Intraoperative, topical irrigation of the exposed arteries. Intravenous infusion until day 7-14 after SAH followed by peroral medication for another week. Nimodipine was well tolerated and neither significant hypotension nor any other adverse reaction attributable to the drug was observed. Ischaemic cerebral dysfunction of delayed onset with permanent neurological deficit occurred in 2 patients (2%). Another 8 patients showed transient ischaemic symptoms. At 6 months follow-up, 93% of the patients were classified as having made a full recovery, 16% as being minimally disabled, 5% as being moderately disabled and 3% as being severely disabled. Three patients had died. The present study supports the concept that preventive nimodipine treatment may reduce delayed ischaemic deficit in early aneurysm surgery.

Current management of cerebral aneurysms: is it based on facts or myths?

The overall morbidity and mortality from aneurysmal subarachnoid hemorrhage have not changed significantly over the past 30 years in spite of great progress in surgical technology and diagnostic capabilities. Most series report major morbidity and mortality figures of approximately 60%. The reason for the currently poor prognosis is due, in part, to the sometimes devastating effect of the initial hemorrhage over which we have no control. Another reason for our inability to improve these dismal statistics may be that the currently accepted treatment regimens have proven to be ineffective. Eighteen misconceptions or "myths" surrounding the treatment of aneurysmal subarachnoid hemorrhage have been identified as factors that have largely determined the currently accepted, ineffective treatment protocols, and these are discussed.

Effect of the calcium antagonist nimodipine on local cerebral blood flow and metabolic coupling

The effects of a continuous infusion of the calcium antagonist nimodipine (1 microgram kg-1 min-1) on local CBF (LCBF) and local cerebral glucose utilisation (LCGU) were studied, using the quantitative autoradiographic [14C]iodoantipyrine and [14C]2-deoxyglucose techniques in 34 anatomically discrete regions of the brain in lightly restrained, conscious rats. The infusion of nimodipine at this concentration produced only a small (8%) reduction in the MABP. The administration of nimodipine did not alter the rate of glucose utilisation in any of the regions examined. By contrast, in 24 regions, CBF was increased significantly by 39-84% from control levels (for example, cerebral cortices, hippocampus, hypothalamus, and most thalamic nuclei). In vehicle-treated animals, there was an excellent correlation (p less than 0.01) between the local levels of CBF and glucose utilisation, with the ratio of flow to glucose use being approximately 1.5 ml mumol-1 in each brain region. During nimodipine treatment, there was a similarly excellent correlation (p less than 0.01) between LCBF and LCGU, but the median ratio between local flow and glucose use increased to 2.5 ml mumol-1.

Implications of nimodipine prophylaxis of cerebral vasospasm on anesthetic management during intracranial aneurysm clipping

Nimodipine, a calcium entry blocking agent similar in structure to nifedipine but with selective cerebrovascular dilating effects, has potential use in the therapy and prevention of cerebral vasospasm after intracranial hemorrhage. The authors summarize the effects of calcium entry blockers, review the pharmacology of nimodipine, and discuss both the known and possible interactions of oral nimodipine with physical and pharmacological interventions that neuroanesthesiologists employ for patients with cerebral vasospasm during craniotomy for aneurysm clipping. In a series of 26 patients undergoing aneurysm clipping, the authors found that intraoperative blood pressure tended to be reduced by nimodipine. Although the number of patients was limited by the fact that they were enrolled in a multi-center nimodipine aneurysm study and thus had to meet the criteria for that study, it is concluded that prophylaxis of cerebral vasospasm with nimodipine in patients with ruptured intracranial aneurysm results only in a favorable tendency toward lower systemic blood pressure during craniotomy.

Second-generation calcium antagonists: search for greater selectivity and versatility

Calcium antagonists have a variable specificity for cardiac and peripheral activity. Based on such activity, these compounds, new and old, can be classified into 4 categories. Type 1 agents, typified by verapamil, its congeners (tiapamil and gallopamil) and diltiazem, prolong atrioventricular nodal conduction and refractoriness with little effect on ventricular or atrial refractoriness. These actions, to a large extent, account for the antiarrhythmic properties of this type of calcium antagonists. Type 2 agents include nifedipine and other dihydropyridines. In vivo, these agents are devoid of electrophysiologic effects in usual doses and concentrations. They are potent peripheral vasodilators with some selectivity of action for different vascular beds; their overall hemodynamic effects are dominated by this peripheral vasodilatation and reflex augmentation of sympathetic reflexes. Type 3 agents are flunarizine and cinnarizine (piperazine derivatives); in vitro and vivo, they are potent dilators of peripheral vessels, with no corresponding calcium-blocking actions in the heart. Type 4 agents (perhexiline, lidoflazine and bepridil) have a broader pharmacologic profile; they block calcium fluxes in the heart, in the peripheral vessels or in both. They may inhibit the fast channel in the heart and have other electrophysiologic actions. A clear understanding of the varied pharmacologic properties of the different classes of calcium antagonists is likely to provide a rational basis for the use of the newer agents in clinical therapeutics.(ABSTRACT TRUNCATED AT 250 WORDS)

[Effect of the Ca antagonist nimodipine on global and regional cerebrovascular circulation]

The effects of Nimodipine on the global and regional cerebral blood flow were studied in 42 patients with cerebrovascular disorders. In 25 patients with focal deficits such as transitory ischemic attack (TIA), prolonged reversible ischemic neurological deficit (PRIND), and minor stroke due to arteriosclerosis, and in eleven patients with cerebral vasospasm after subarachnoid hemorrhage, the cerebral blood flow was measured by 133Xenon inhalation technique 60 min after oral administration of 40, 60, or 80 mg Nimodipine. In 6 patients with vasospasm the effects of Nimodipine i.v. were examined. The result in twelve patients with minor stroke who were only given placebo (lactose; "test-retest") was identical regional (rCBF) and global (CBF) cerebral blood flow before and 60 min after; placebo, blood pressure, and arterial pCO2 remained constant as well. After Nimodipine, however, the CBF increases, the increase after vasospasm being significant when taking the pCO2 in the Wilcoxon test into account. The rCBF increases much more in the regions with low perfusion rates than in well-perfused areas. This is also observed in the patients with TIA, PRIND, or minor stroke, most clearly after oral administration of 60 mg, whereas regions with normal perfusion rates show little reaction. The blood pressure was lowered, depending on the initial pressure. There was no evidence of a steal phenomenon.

Failure of nimodipine to reverse acute experimental spinal cord injury

The calcium-channel blocking agent, nimodipine, was administered to cats for 5 days after acute experimental SCI. Six weeks after injury, no significant differences in neurologic recovery or white matter tissue preservation at the injury site were found between treated and control animals.

Outcome in 60 consecutive patients treated with early aneurysm operation and intravenous nimodipine

Sixty consecutive patients with a ruptured supratentorial aneurysm underwent operation during the acute stage, 56 of them within 72 hours after the first bleed, one on the 4th day, and three on the 5th day. Six patients were classified preoperatively in Hunt and Hess neurological Grade I, 39 in Grade II, 11 in Grade III, and four in Grade IV or V. Nine patients had severe intracerebral hematomas, and one patient had a subdural hematoma. After the aneurysm was clipped, nimodipine was applied to the exposed arterial segments in a 2.5 X 10(-5)M solution for 10 minutes. Subsequently, all patients received a continuous intravenous nimodipine infusion (2 mg/hr) for 7 to 12 days, followed by oral treatment (270 mg/day). Forty-six patients (77%) made a good neurological recovery; the morbidity rate was 22%, and mortality rate 1.5%. Of the 45 patients in good condition (Grades I to II) preoperatively, 38 (84%) made a good neurological recovery. Two patients (3% of the total series) developed a typical picture of cerebral ischemic dysfunction of delayed onset with subsequent fixed neurological deficits. The results favor the opinion that early operative intervention is beneficial in patients in good condition rather than delaying surgery, and indicate that nimodipine provides an additional anti-ischemic effect. The appearance and severity of late angiographic vasospasm did not seem to be affected by nimodipine.

Effect of the calcium antagonist nimodipine on local cerebral blood flow: relationship to arterial blood pressure

The effect of the calcium antagonist nimodipine on local CBF in 31 regions of the CNS was studied with the [14C]iodoantipyrine autoradiographic technique in lightly anaesthetised, mechanically ventilated rats. Continuous intravenous infusion of nimodipine (1, 2, or 4 micrograms kg-1 min-1) produced a dose-dependent reduction in MABP (reduced by 26 +/- 2% after 30 min of nimodipine, 4 micrograms kg-1 min-1) and a significant elevation in plasma glucose concentration (increased by 44 +/- 2% after 30 min of nimodipine, 4 micrograms kg-1 min-1). Local CBF was increased significantly during infusions of nimodipine (1 microgram kg-1 min-1) in 9 of the 31 regions examined (including the cerebral cortex, hippocampus, hypothalamus, and most thalamic nuclei). In contrast to the increases in CBF observed in forebrain regions, no significant increases in CBF were observed during nimodipine infusions in regions of the lower brainstem, cerebellum, and pons or in myelinated fibre tracts. The proportionately greatest increases in local CBF were observed during infusions of the lowest dosage of nimodipine (1 microgram kg-1 min-1), suggesting either that this dosage provokes maximum cerebrovascular relaxation or that effects of increasing concentrations are counteracted by the concomitant systemic hypotension.

Calcium antagonists, cerebral ischemia and vasospasm

The past fifteen years has seen the classification of diverse substances into a group known as calcium antagonists (CAs). They have a common ability to reduce the transmembrane transport of extracellular calcium ions (CAe2+). This flow of calcium into vascular smooth muscle is ultimately associated with the development of tension and vasoconstriction. Some CAs appear to have a predilection for cerebral as opposed to systemic arteries and so may function as specific cerebral arterial vasodilators. It has been proposed that they might be useful in certain types of cerebral ischemia such as that due to arterial occlusion or prolonged vasoconstriction. Animal experiments and initial clinical trials give grounds for cautious optimism that CAs may become as useful in neurology as they have recently become in cardiology.

Acute surgery of cerebral aneurysms and prevention of symptomatic vasospasm

A treatment protocol for a controlled open study in patients with subarachnoid haemorrhage (SAH) from cerebral aneurysms is presented, applying acute surgery and pharmacological prevention of symptomatic vasospasm: In patients clinically graded I-III (Hunt and Hess), operation is performed within 48 to 72 hours. After aneurysm clipping, the calcium-antagonist Nimodipine is administered 1. topically during operation, 2. intravenously until day 14 after SAH, 3. perorally until day 21 after SAH. Preliminary results in the first 31 patients show no management mortality and no severe management morbidity. Severe symptomatic vasospasm has never occurred. At 3 months follow-up investigation in 27 of the 31 patients, 5 had minimal neurological deficit; all patients are fully resocialized, working in their previous professions.