Vasospasm after subarachnoid hemorrhage: interest in diffusion-weighted MR imaging

BACKGROUND AND PURPOSE

Vasospasm secondary to subarachnoid hemorrhage (SAH) is responsible for severe ischemic complications. Although effective, angioplasty must be performed at a very early stage to produce any clinical recovery. Diagnostic investigations to assess arterial narrowing (transcranial Doppler, angiography) or cerebral perfusion (xenon CT, single-photon emission CT) do not provide evidence of the extent of parenchymal ischemia. In stroke, diffusion-weighted MR imaging (DWI) appears to be the most sensitive procedure to detect cerebral ischemia. We studied asymptomatic vasospasm in patients with aneurysmal SAH to assess whether DWI provides predictive markers of silent ischemic lesions and/or progression toward symptomatic ischemia.

METHODS

Seven asymptomatic vasospasm patients (average blood velocity rates >120 cm/s), 3 patients with symptomatic vasospasm, and 4 patients with SAH but without vasospasm were studied at regular intervals by DWI, and their apparent diffusion coefficients (ADCs) were calculated.

RESULTS

All patients with vasospasm including those without symptoms presented abnormalities on DWI with a reduction of the ADC prevalently in the white matter. No such abnormalities were observed in patients without vasospasm. The abnormalities on DWI resolved completely in 4 of the 7 patients, with no parenchymal lesion. Resolution was partial in 3 patients whose white matter still presented residual round, focal ischemic lesions.

CONCLUSIONS

Being able to correlate abnormalities on DWI with parenchymal involvement in asymptomatic patients would be of considerable clinical significance. It is hoped that larger studies will be undertaken to determine whether the ADC has a reversibility threshold, because this would facilitate patient management.

The surgical management of contralateral anterior circulation intracranial aneurysms

This study reviews the surgical management of contralateral anterior circulation aneurysms in patients with bilateral intracranial aneurysms repaired following a unilateral craniotomy. Between 1993 and 1999, 27 patients had 88 intracranial aneurysms repaired. Eleven patients presented following subarachnoid haemorrhage. Excluding midline aneurysms, 31 anterior circulation aneurysms were contralateral to the craniotomy and all were repaired at the same time that ipsilateral or midline aneurysms were repaired. Morbidity included one death and one case of loss of unilateral vision directly attributable to surgery and two cases of cerebral infarction due to vasospasm. No new neurological deficit or mortality could be directly attributed to the repair of a contralateral aneurysm. The repair of all accessible aneurysms, including those contralateral to the craniotomy, during one session avoids the risk of haemorrhage from incidental or unrecognised ruptured aneurysms (particularly during the aggressive treatment of vasospasm), avoids a second craniotomy, decreases overall hospitalisation and can improve visualisation of carotid-ophthalmic aneurysms.

Anticoagulation and induced hypertension after endovascular treatment for ruptured intracranial aneurysms

OBJECTIVE

Guglielmi detachable coil (GDC) embolization may be used to prevent early rebleeding after aneurysmal subarachnoid hemorrhage, but anticoagulation and induced hypertension may increase this risk. We sought to determine retrospectively the relationship between levels of induced hypertension and anticoagulation and incidence of rebleeding in GDC-treated patients.

METHODS

Twenty-five consecutive patients with acute (<14 days) subarachnoid hemorrhage who underwent GDC embolization were retrospectively analyzed with regard to percent obliteration of an aneurysm on postprocedure angiogram, the duration and intensity of anticoagulation, the duration and level of induced hypertension, and the frequency of thromboembolic and rebleeding complications.

RESULTS

Complete angiographic obliteration of the aneurysm was achieved in five cases (20%). In some cases (n = 2), only the dome of the aneurysm was coiled to allow eventual surgical clipping. Heparin was given to 23 patients (92%) for an average of 6 days (range, 8 hrs to 22 days); the mean dose was 588 units/hr, and the mean partial thromboplastin time was 37 secs. Seven patients (28%) were treated with vasopressors for symptomatic vasospasm for a mean duration of 5 days (range, 8 hrs to 9 days); mean arterial blood pressure averaged 118 mm Hg, and peak systolic blood pressures ranged from 195 to 250 mm Hg. There were no episodes of aneurysm rebleeding. Three patients (12%) suffered intraoperative thromboembolic complications, which in one instance was fatal; two of these cases were associated with subtherapeutic partial thromboplastin time values.

CONCLUSION

Induced hypertension (mean arterial blood pressure, 120 mm Hg) and heparinization do not appear to increase the risk of early rebleeding after GDC embolization. In a select group of patients, use of anticoagulation in the immediate perioperative period to prevent thromboembolic complications appears to be safe.

Temporal relationship between endothelin-1 concentrations and cerebral vasospasm in patients with aneurysmal subarachnoid hemorrhage

BACKGROUND AND PURPOSE

Endothelin 1 (ET-1) is a potent vasoconstrictor that may play a role in cerebral vasospasm following subarachnoid hemorrhage (SAH). However, data regarding its pathogenic role in the development of vasospasm are controversial. We planned a prospective, observational clinical study to investigate the temporal relationship between increased ET-1 production and cerebral vasospasm or other neurological sequelae after SAH.

METHODS

ET-1 levels in cerebrospinal fluid (CSF) were measured in 20 SAH patients from admission (within 24 hours from the bleeding) until day 7. Patients received a daily transcranial Doppler study and a neurological evaluation. On day 7, angiography was performed to verify the degree and extent of vasospasm. Patients were then classified as having (1) clinical vasospasm, (2) angiographic vasospasm, (3) no vasospasm, or (4) poor neurological condition without significant vasospasm (low Glasgow Coma Scale score [GCS]).

RESULTS

On admission, ET-1 levels were increased in the low-GCS group compared with the other groups (P=0.04). On day 4 ET-1 levels were not significantly different among groups, whereas on day 7 ET-1 levels were significantly increased in both the clinical vasospasm and low-GCS groups compared with the angiographic vasospasm and no vasospasm groups (P<0.005). Moreover, when the low-GCS group was excluded, there was a significant relationship between vasospasm grade and CSF ET-1 levels (R(2)=0.73).

CONCLUSIONS

CSF ET-1 levels were markedly elevated in patients with clinical manifestations of vasospasm (day 7) and with a poor neurological condition not related to vasospasm. However, ET-1 levels were low in clinical vasospasm patients before clinical symptoms were evident (day 4) and remained low in angiographic vasospasm patients throughout the study period. Thus, our data suggest that CSF ET-1 levels are increased in conditions of severe neuronal damage regardless whether this was due to vasospasm or to the primary hemorrhagic event. In addition, CSF ET-1 levels paralleled the neurological deterioration but were not predictive of vasospasm.

Aneurysms of the lateral spinal artery: report of two cases

OBJECTIVE AND IMPORTANCE

The goal of this report was to describe aneurysms arising from the lateral spinal artery. The locations of aneurysms contributing to subarachnoid hemorrhage (SAH) have been well characterized and are primarily in the circle of Willis or at the bifurcation points of the internal carotid artery or the vertebrobasilar system. Although the spinal arteries are also in direct communication with the subarachnoid space, aneurysms of these arteries that lead to SAH are rare. To date, only aneurysms of the anterior and posterior spinal arteries have been described. In this communication, we report two patients with aneurysms of the lateral spinal artery who presented with SAH.

CLINICAL PRESENTATION

Review of our neurointerventional database from 1997 to the present revealed two patients with lateral spinal artery aneurysms. The medical records, as well as the operative and radiological findings, were reviewed for both patients. In both cases, the lateral spinal arteries were involved as collateral pathways for occlusive vertebral lesions, suggesting hemodynamic stress as a cause.

INTERVENTION

Endovascular treatment was attempted in both cases and was successful in one; open surgery, with aneurysm resection, was performed in the other case. We review the vascular anatomic features of the spinal cord as they relate to the lateral spinal artery, as well as treatment options for lateral spinal artery aneurysms.

CONCLUSION

Lateral spinal artery aneurysms are a rare cause of SAH. Both endovascular and surgical treatment options are available.

Susac syndrome: a vasospastic disorder?

PURPOSE

The Susac syndrome is a microangiopathy that leads to visual symptoms, hearing loss and neurological symptoms.

CASE REPORT

We report on a young woman suffering from this syndrome who also presented the following signs and symptoms typical of a vasospastic syndrome; 1) a history of cold hands, low blood pressure and migraine; 2) a typical alteration of conjunctival vessels; 3) prolonged flow arrest time after cooling in nailfold capillaromicroscopy; 4) increased resistivity in the orbital vessels measured by color Doppler imaging; and 5) an increased plasma level of endothelin-1.

CONCLUSIONS

We postulate that the Susac syndrome is a manifestation of the vasospastic syndrome.

Evaluation of cerebral vasospasm with transcranial magnetic stimulation: an experimental study

Despite the current use of several different methods for diagnosis and follow-up of cerebral vasospasm after subarachnoid hemorrhage, an easy, quick, reliable, and noninvasive method is still needed for evaluation of this entity. We investigated the value of transcranial magnetically evoked motor potential changes during the vasospasm period in a rabbit experimental subarachnoid hemorrhage model. We also recorded motor evoked potential changes after deferoxamine treatment during vasospasm. Our results reveal a significant increase in latency periods of evoked potentials during the angiographically proven vasospasm period (34.5%) over those in sham-operated rabbits (9.5%). With deferoxamine treatment, only a minor increase in latency periods (4.5%) was detected after subarachnoid hemorrhage. These results suggest the potential value of evoked motor potential recording as a diagnostic tool in cases of cerebral vasospasm.

[Vasospasm, part I: clinical symptomatology and differential diagnosis]

Vasospasm is the most dangerous and common complication of subarachnoid haemorrhage (SAH) from ruptured brain aneurysms. The frequency of vasospasm is between 11 to 72% of SAH cases. One of the consequences of vasospasm is delayed neurological deficit (DND). Clinical diagnosis of vasospasm can course many diagnostic and therapeutic problems. This paper reviews the current developments concerning history, clinical picture and differential diagnosis of vasospasm.

Review of medical prevention of vasospasm after aneurysmal subarachnoid hemorrhage: a problem of neurointensive care

Cerebral vasospasm remains a devastating medical complication of aneurysmal subarachnoid hemorrhage (SAH). It is associated with high morbidity and mortality rates, even after the aneurysm has been secured surgically or radiologically. A great deal of experimental and clinical research has been conducted in an effort to find ways to prevent this complication. The literature includes extensive coverage of in vivo animal model studies of SAH and vasospasm. These experimental studies have contributed to tremendous advances in the understanding of the mechanisms leading to cerebral vasospasm. Most of the experimental settings, however, have demonstrated varying levels of ability to predict accurately what occurs in human SAH. Therefore, although animal models have been developed to test new therapies, most of the treatment effects have been shown to be less compelling when trials have been conducted in clinical settings. The interpretation of current literature is complicated further by the imprecise estimation of the incidence of cerebral vasospasm, which is due to various degrees of clinical expression, ranging from the absence of symptoms in the presence of increased blood flow velocities at transcranial Doppler or vessel diameter reduction at angiography to neurological manifestations of severe ischemic deficits. In addition, a change over time in the incidence pattern of human SAH and vasospasm, possibly related to improved surgical techniques and overall patient management, may have occurred. This topic review collects the relevant literature on clinical trials investigating prophylactic therapies for cerebral vasospasm in patients with aneurysmal SAH and emphasizes the need for large clinical trials to confirm the results derived from clinical experience. In addition, it points out some experimental therapies that may hold promise in future clinical trials to prevent the occurrence of vasospasm.

Increase and uncoupling of adrenomedullin from the natriuretic peptide system in aneurysmal subarachnoid hemorrhage

OBJECT

Natriuresis is a common systemic manifestation of aneurysmal subarachnoid hemorrhage (SAH). Natriuresis and its accompanying hypovolemia may be a major contributing factor in the pathophysiology of symptomatic cerebral vasospasm.

METHODS

The authors studied 14 consecutive patients with aneurysmal SAH and compared levels of adrenomedullin (ADM), a novel endogenous natriuretic peptide that possesses additional profound vasodilatory properties, with the natriuretic peptide system by using radioimmunoassay. The mean ADM values on admission were 24.8 pg/ml, a twofold increase over control values, but no correlation was found with atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and C-natriuretic peptide (CNP) from the natriuretic peptide system. At Day 5 post-SAH, ADM levels were significantly elevated in patients with vasospasm documented angiographically or on transcranial Doppler studies as compared with those who suffered no vasospasm (mean 61.9 pg/ml compared with 15.3 pg/ml, p < 0.01).

CONCLUSIONS

The authors conclude that an elevation of ADM in plasma may indicate a physiological regulatory attempt to induce cerebral vasodilation. The regulation of ADM is uncoupled from ANP, BNP, and CNP.

Health-related quality of life after aneurysmal subarachnoid hemorrhage: impacts of bleeding severity, computerized tomography findings, surgery, vasospasm, and neurological grade

OBJECT

Based on the results of earlier studies it is agreed that the significance of aneurysm location and surgery for neuropsychological impairments after subarachnoid hemorrhage (SAH) is secondary to the effects of the bleeding itself. Therefore, the present study was performed to evaluate whether bleeding, acute clinical course, and surgery have persistent effects on health-related quality of life (QOL) after SAH.

METHODS

A series of 116 patients was examined for 4 to 5 years (mean 52.2 months) after aneurysmal SAH by means of a QOL questionnaire. Eighty-six patients (74.1%) had undergone surgery early (< or = 72 hours post-SAH). There were 77 women (66.4%) and 39 men (33.6%) in the study group, and the mean age of the patients was 50.3+/-13.3 years (range 30-69 years). Patients who had undergone surgery for a left-sided middle cerebral artery (MCA) aneurysm complained of significantly more impairments in social contact, communication, and cognition than those treated for a right-sided MCA aneurysm. No other effects of aneurysm location (including the anterior communicating artery) emerged. Multiple aneurysms, intraoperative aneurysm rupture, and partial resection of the gyrus rectus had no adverse effects on later daily life. Only temporary clipping was associated with increased complaints in some QOL areas. Disturbances of the circulation of cerebrospinal fluid and the presence of intraventricular hemorrhage led to more impairments in daily life. Specific effects of the anatomical pattern of the bleeding could be identified, but no adverse effects of vasospasm were found. Multivariate analyses revealed, in particular, that patient age and admission neurological status (Hunt and Hess grade) are substantial predictors of the psychosocial sequelae of SAH.

CONCLUSIONS

In contrast to the mild effects of aneurysm surgery, patient's age, initial neurological state on admission, and the bleeding pattern substantially influence late QOL after SAH.

Estimation of cerebral oxygenation and hemodynamics in cerebral vasospasm using indocyaningreen dye dilution and near infrared spectroscopy: a case report

Changes in cerebral hemodynamics and oxygenation patterns in cerebral vasospasm might be underestimated if transcranial doppler sonography and angiography findings are considered singularly. This report describes preliminary findings in further development of a noninvasive method that estimates regional cerebral oxygenation and perfusion. A 50-year-old patient suffering from cerebral vasospasm after subarachnoid hemorrhage before and after superselective papaverine infusion was examined. Measurements were taken by using a technique combining indocyaningreen dye dilution and near infrared spectroscopy. Our first results suggest that the technique could be suitable for estimation of cerebral hemodynamics. This noninvasive technique can be performed at the bedside and in special environments, such as neurocritical care units. It seems to be safe, easy to perform, and less time-consuming than conventional techniques. Combination of indocyaningreen dye dilution and near infrared spectroscopy might become a powerful tool in the detection and treatment of cerebral vasospasm causing delayed cerebral ischemic deficit. Further larger-scale investigations are necessary to evaluate the diagnostic accuracy of this technique. Our preliminary observations however, based on measurements before and after superselective papaverine infusion in vasospastic vessels, helped to clarify the influence of extracerebral contamination on the cerebral near infrared spectroscopy signal in the adult head.

Vasospasm after subarachnoid hemorrhage: diagnosis with MR angiography

BACKGROUND AND PURPOSE

The possibility of treating intracranial vasospasm has increased the significance of its diagnosis and follow-up; however, so far, no ideal method is available. The goal of this study was to assess the accuracy of MR angiography versus intraarterial angiography (IA-DSA) in detecting vasospasm.

METHODS

The study included 42 patients with acute spontaneous subarachnoid hemorrhage (SAH). Serial MR angiograms (minimum, two per patient within 10 days after the event; total, 149) were obtained prospectively using a 3D time-of-flight technique covering the circle of Willis at 0.5 T. Forty-seven MR angiograms could be compared with intraarterial angiograms obtained within 24 hours of MR angiography. Vascular narrowing on both studies was rated consensually by two pairs of neuroradiologists using a scale from 0 (no narrowing) to 3 (severe narrowing). Categories 0 and 1 were considered an absence of vasospasm and categories 2 and 3 a presence of vasospasm.

RESULTS

Agreement between MR angiography and IA-DSA (assessed with weighted kappa statistics) was substantial for the middle and anterior cerebral arteries (MCA and ACA) but moderate for the internal carotid artery (ICA). The sensitivity, specificity, accuracy, and positive and negative predictive values of MR angiography for detecting patients with vasospasm were 92%, 98%, 96%, 92%, and 98%, respectively. Considering each vessel separately, specificity was high for all locations (95-99%) and sensitivity was excellent for the ACA (100%) but poorer for the ICA (25%) and MCA (56%).

CONCLUSION

MR angiography at 0.5 T is capable of identifying vasospasm after acute SAH but is less sensitive than IA-DSA for depicting vasospasm in the ICA and MCA.

Vasospasm of the internal auditory artery: significance in cerebellopontine angle surgery

BACKGROUND

Cochlear ischemia is likely involved in sensorineural hearing loss after cerebellopontine angle (CPA) surgery.

OBJECTIVE

To demonstrate the type of vascular damage to the cochlea, apart from arterial section, that can be induced by CPA surgery.

METHODS

The effects on measures of both cochlear blood flow (CBF) and distortion-product otoacoustic emissions (DPOAEs) of partial or total mechanical compressions of the internal auditory artery (IAA) were compared in young adult rabbits.

RESULTS

When preocclusion baseline activity was compared with postocclusion CBF and DPOAEs, it was clear in the majority of cases that total compressions lasting < or =7 minutes produced the same full recoveries for both measures as did the shorter obstructions of only a few minutes. By contrast, both short and long partial occlusions in which ischemia was interrupted by periods of poor reperfusion (<50% of the initial CBF value) resulted in delayed and prolonged recoveries. In addition, at times, full recovery was not achieved, particularly for DPOAEs, because of vasospasm-like activity.

CONCLUSION

Vasospasm of the IAA was induced by a systematic series of IAA compressions and releases that did not provide for full reperfusion. These data support the concept that vasospasm should be prevented whenever hearing preservation is attempted in CPA surgery.

Fatal severe vasospasm due to rewarming following hypothermia--case report

A 37-year-old female died of cerebral vasospasm as a complication of rewarming following hypothermia therapy for severe head injury. She presented with severe consciousness disturbance and anisocoria after falling down a flight of stairs. Computed tomography (CT) revealed a right acute subdural hematoma and temporal contusion. Following surgery, mild hypothermia was started and rewarming was completed by the 11th day. Neurological examination showed no abnormalities, but intracranial pressure (ICP) suddenly increased and she manifested anisocoria on the 13th day. Repeat CT revealed a low density area in the right middle cerebral artery region and cerebral angiography showed diffuse narrowing of the main arterial trunks. A cerebrospinal fluid (CSF) sample was collected using an intraventricular ICP monitoring catheter. The CSF level of 8-hydroxy-2'-deoxyguanosine was elevated during the rewarming period, indicating substantial deoxyribonucleic acid (DNA) oxidation. She died on the 15th day due to uncontrollable ICP. Histological examination at autopsy of the narrowed artery found the waving phenomenon in the internal elastic lamina and invasion of inflammatory cells into the adventitia. These findings constitute the possible evidence that free-radical-mediated oxidative DNA damage may be important in the genesis of severe vasospasm due to rewarming following hypothermia.

Basilar artery vasospasm in postpartum cerebral angiopathy

The reason cerebral edema in postpartum cerebral angiopathy (PPCA) occurs preferentially in the posterior brain is poorly understood. The authors present two patients with PPCA who showed vasospasm occurring earlier and more severely in the basilar artery than in the middle cerebral artery. Our patients demonstrate the difference in vascular change between the anterior and posterior cerebral vessels, explaining the susceptibility of the posterior brain to PPCA.

Diffusion weighted imaging and magnetic resonance spectroscopy in a low flow ischaemia model due to endothelin induced vasospasm

The aim of this MR study was to determine if vasospasm induced by application of endothelin-1 (ET-1) in the rat brain would model the abnormalities attributed to vasospasm described in patients with subarachnoid haemorrhage (SAH) with reversible neurological deficits. Following application of ET-1 in concentrations of 10(-4) M or 10(-6) M to the middle cerebral artery, there was an immediate drop in pH, an increase in the inorganic phosphate (P(i)) to phosphocreatine (PCr) ratio and elevated lactate. There was gradual recovery to control in the 10(-6) M group, but in the 10(-4) M group there was a loss of approximately 10% in the absolute signal intensities of PCr and adenosine triphosphate (ATP). In a second similarly treated group of animals, the area of the hemisphere with a low apparent diffusion coefficient (ADC) was 27 +/- 6% at 30 min and remained at about 20-21% at 90 min and beyond. Together these data suggest that the regions with persistently low ADC were metabolically compromised, with incomplete recovery of PCr and ATP, and represent irreversibly damaged tissue. This raises the possibility that MR spectroscopy and imaging could be a sensitive indicator of tissue viability. This is a potentially useful model of low flow as seen in clinical vasospasm following SAH.