Evaluation of posttraumatic vasospasm, hyperaemia, and autoregulation by transcranial colour-coded duplex sonography

Low Glasgow Coma Score in Traumatic Intracranial Hemorrhage Predicts Development of Cerebral Vasospasm

BACKGROUND

The exact mechanism, incidence, and risk factors for cerebral vasospasm after traumatic intracranial hemorrhage (ICH) continue to be poorly characterized. The incidence of post-traumatic vasospasm (PTV) varies depending on the detection modality.

OBJECTIVE

We aimed to shed light on the predictors, associations, and true incidence of cerebral vasospasm after traumatic ICH using digital subtraction angiography (DSA) as the gold standard.

METHODS

We examined a prospectively maintained database of traumatic brain injury (TBI) patients to identify patients with ICH secondary to TBI enrolled between 2002 and 2015 at our trauma center. Patients with TBI-associated ICH and evidence of elevated velocities on transcranial Doppler and computed tomography angiograms, confirmed with DSA were included. The diagnostic cerebral angiograms were evaluated by 2 blinded neurointerventionalists for cerebral vasospasm. Statistical analyses were conducted to determine predictors of PTV.

RESULTS

Twenty patients with ICH secondary to TBI and evidence of vasospasm underwent DSAs. Seven patients (7/20; 35%) with traumatic ICH developed cerebral vasospasm and of those, 1 developed delayed cerebral ischemia (1/7; 14%). Of these 7 patients, 6 presented with subarachnoid hemorrhage (6/7; 85%). Vasospasm was substantially more common in patients with a Glasgow Coma Scale <9 (P = 0.017) than in all other groups.

CONCLUSIONS

PTV as demonstrated by DCA may be more common than previously reported. Patients who exhibit PTV were more likely to have a Glasgow Coma Scale <9. This subgroup of patients may benefit from more systematic screening for the development of PTV, and earlier monitoring for signs of delayed cerebral ischemia.

Pressure Autoregulation Measurement Techniques in Adult Traumatic Brain Injury, Part I: A Scoping Review of Intermittent/Semi-Intermittent Methods

The purpose of this study was to perform a systematic, scoping review of commonly described intermittent/semi-intermittent autoregulation measurement techniques in adult traumatic brain injury (TBI). Nine separate systematic reviews were conducted for each intermittent technique: computed tomographic perfusion (CTP)/Xenon-CT (Xe-CT), positron emission tomography (PET), magnetic resonance imaging (MRI), arteriovenous difference in oxygen (AVDO₂) technique, thigh cuff deflation technique (TCDT), transient hyperemic response test (THRT), orthostatic hypotension test (OHT), mean flow index (Mx), and transfer function autoregulation index (TF-ARI). MEDLINE^®, BIOSIS, EMBASE, Global Health, Scopus, Cochrane Library (inception to December 2016), and reference lists of relevant articles were searched. A two tier filter of references was conducted. The total number of articles utilizing each of the nine searched techniques for intermittent/semi-intermittent autoregulation techniques in adult TBI were: CTP/Xe-CT (10), PET (6), MRI (0), AVDO₂ (10), ARI-based TCDT (9), THRT (6), OHT (3), Mx (17), and TF-ARI (6). The premise behind all of the intermittent techniques is manipulation of systemic blood pressure/blood volume via either chemical (such as vasopressors) or mechanical (such as thigh cuffs or carotid compression) means. Exceptionally, Mx and TF-ARI are based on spontaneous fluctuations of cerebral perfusion pressure (CPP) or mean arterial pressure (MAP). The method for assessing the cerebral circulation during these manipulations varies, with both imaging-based techniques and TCD utilized. Despite the limited literature for intermittent/semi-intermittent techniques in adult TBI (minus Mx), it is important to acknowledge the availability of such tests. They have provided fundamental insight into human autoregulatory capacity, leading to the development of continuous and more commonly applied techniques in the intensive care unit (ICU). Numerous methods of intermittent/semi-intermittent pressure autoregulation assessment in adult TBI exist, including: CTP/Xe-CT, PET, AVDO₂ technique, TCDT-based ARI, THRT, OHT, Mx, and TF-ARI. MRI-based techniques in adult TBI are yet to be described, with the main focus of MRI techniques on metabolic-based cerebrovascular reactivity (CVR) and not pressure-based autoregulation.

Risk factors for posttraumatic vasospasm

OBJECT

Posttraumatic vasospasm (PTV) is an underrecognized cause of ischemic damage after severe traumatic brain injury (TBI) that independently predicts poor outcome. There are, however, no guidelines for PTV screening and management, partly due to limited understanding of its pathogenesis and risk factors.

METHODS

A database review of 46 consecutive cases of severe TBI in pediatric and adult patients was conducted to identify risk factors for the development of PTV. Univariate analysis was performed to identify potential risk factors for PTV, which were subsequently analyzed using a multivariate logistic regression model to calculate odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Fever on admission was an independent risk factor for development of PTV (OR 22.2, 95% CI 1.9-256.8), and patients with hypothermia on admission did not develop clinically significant vasospasm during their hospital stay. The presence of small parenchymal contusions was also an independent risk factor for PTV (OR 7.8, 95% CI 0.9-69.5), whereas the presence of subarachnoid hemorrhage or other patterns of intracranial injury were not. Other variables, such as age, sex, ethnicity, degree of TBI severity, or admission laboratory values, were not independent predictors for the development of clinically significant PTV.

CONCLUSIONS

Independent risk factors for PTV include parenchymal contusions and fever. These results suggest that diffuse mechanical injury and activation of inflammatory pathways may be underlying mechanisms for the development of PTV, and that a subset of patients with these risk factors may be an appropriate population for aggressive screening. Further studies are needed to determine if treatments targeting fever and inflammation may be effective in reducing the incidence of vasospasm following severe TBI.

The evolution of the treatment of traumatic cerebrovascular injury during wartime

The approach to traumatic craniocervical vascular injury has evolved significantly in recent years. Conflicts prior to Operations Iraqi and Enduring Freedom were characterized by minimal intervention in the setting of severe penetrating head injury, in large part due to limited far-forward resource availability. Consequently, sequelae of penetrating head injury like traumatic aneurysm formation remained poorly characterized with a paucity of pathophysiological descriptions. The current conflicts have seen dramatic improvements with respect to the management of severe penetrating and closed head injuries. As a result of the rapid field resuscitation and early cranial decompression, patients are surviving longer, which has led to diagnosis and treatment of entities that had previously gone undiagnosed. Therefore, in this paper the authors' purpose is to review their experience with severe traumatic brain injury complicated by injury to the craniocervical vasculature. Historical approaches will be reviewed, and the importance of modern endovascular techniques will be emphasized.

Posttraumatic vasospasm detected by continuous brain tissue oxygen monitoring: treatment with intraarterial verapamil and balloon angioplasty

INTRODUCTION

Posttraumatic vasospasm (PTV) is a relatively common event following traumatic brain injury (TBI) that has been strongly correlated with worse neurological outcome in many studies. However, vasospasm continues to be an under-recognized source of secondary injury following TBI, and currently published guidelines do not address screening or management strategies for PTV. Brain tissue oxygen (P(bt)O(2)) monitoring probes allow for continuous screening for cerebral hypoxia following TBI, but their use as a monitor for PTV has not been previously described.

METHODS

Case report and literature review.

RESULTS

We present a case of PTV identified by persistent low P(bt)O(2) despite aggressive medical therapy. Computed tomography and digital subtraction angiography confirmed severe cerebral arterial vasospasm involving both anterior and posterior circulations. The patient was successfully treated with serial intraarterial therapy including balloon angioplasty and verapamil infusion.

CONCLUSION

Posttraumatic vasospasm should be included in the differential diagnosis of cerebral hypoxia (e.g., low P(bt)O(2)) following TBI. Management strategies for PTV may include early, aggressive intraarterial therapies including drug infusion and balloon angioplasty.

The endovascular operating room as an extension of the intensive care unit: changing strategies in the management of neurovascular disease

Technological advances within the field of endovascular neurosurgery have influenced the management of the neurovascular patient within the intensive care unit (ICU). The endovascular operating room has, in fact, become an extension of the ICU in certain cases. Given the rapid development of new endovascular technologies, it is more important than ever for neurosurgeons to remain intimately involved with the care of their patients within the ICU. This article offers an overview of the evolution in ICU management of neurovascular disease and provides a framework for the incorporation of the endovascular operating room in the intensive care management of patients with this disease.

Wartime traumatic cerebral vasospasm: recent review of combat casualties

OBJECTIVE

Blast-related neurotrauma is associated with the severest casualties from Operation Iraqi Freedom (OIF). A consequence of this is cerebral vasospasm. This study evaluated all inpatient neurosurgical consults related to battle injury from OIF.

METHODS

Evaluation of all admissions from OIF from April 2003 to October 2005 was performed on patients with neurotrauma and a diagnostic cerebral angiogram. Differences between patients with and without vasospasm and predictors of vasospasm were analyzed.

RESULTS

Fifty-seven out of 119 neurosurgical consults were evaluated. Of these, 47.4% had traumatic vasospasm; 86.7% of patients without vasospasm and 80.8% of patients with vasospasm sustained blast trauma. Average spasm duration was 14.3 days, with a range of up to 30 days. Vasospasm was associated with the presence of pseudoaneurysm (P = 0.05), hemorrhage (P = 0.03), the number of lobes injured (P = 0.012), and mortality (P = 0.029). Those with vasospasm fared worse than those without (P = 0.002). The number of lobes injured and the presence of pseudoaneurysm were significant predictors of vasospasm (P = 0.016 and 0.02, respectively). There was a significant quadratic trend towards neurological improvement for those receiving aggressive open surgical treatment (P = 0.002). In the vasospasm group, angioplasty with microballoon significantly lowered middle cerebral artery and basilar blood-flow velocities(P = 0.046 and 0.026, respectively).

CONCLUSION

Traumatic vasospasm occurred in a substantial number of patients with severe neurotrauma, and clinical outcomes were worse for those with this condition. However, aggressive open surgical and endovascular treatment strategies may have improved outcome. This was the first study to analyze the effects of blast-related injury on the cerebral vasculature.

Detection and monitoring of cerebral hemodynamic disturbances with transcranial color-coded duplex sonography in patients after head injury

Reduced cerebral blood flow after severe head injury results in an increased risk of ischemic brain damage. Blood flow should therefore be monitored with a simple, reliable method. Transcranial color-coded Doppler sonography (TCCS) is an accepted tool for the diagnosis of cerebral vasospasm; however, its usefulness in evaluating patients with head injury has not been proven. Cerebral blood-flow velocity in the middle, anterior, and posterior cerebral arteries was measured with a 2.5 MHz probe (Aplio SSA 770A, Toshiba, Japan) in 36 subjects with moderate or severe head injury. Serial measurements of resistance index (RI), peak-systolic, end-diastolic, and mean velocity in the middle cerebral arteries were performed 2-24 h after head trauma and in the subsequent days during hospitalization. Immediately after head trauma, increased RI values, and unusually decreased blood-flow velocity (mainly in MCA) were observed. Microcirculation disturbances were suspected because the end-diastolic velocity had substantially diminished. Changes in blood-flow parameters correlated with the clinical state, and in most cases, a poor prognosis. In some patients, blood-flow velocity increased above the normal reference limit and this implied poor prognosis. Transcranial color-coded Doppler sonography is a reliable, repeatable, and accessible tool that provides information about cerebral blood-flow disturbances and may hold diagnostic and prognostic importance.

The transsylvian approach is "minimally invasive" but not "atraumatic"

OBJECTIVE

In light of the competition between microneurosurgery and alternative methods such as stereotactic radiosurgery, we tested the hypothesis that changes in the cerebral circulation after microneurosurgery are common among patients without evidence of cerebrovascular or neoplastic disease.

METHODS

Blood flow velocities (BFVs) were recorded with transcranial Doppler ultrasonography, before surgery and every other day after surgery, for a group of 50 patients who underwent transsylvian selective amygdalohippocampectomies for treatment of hippocampal sclerosis. Hexamethylpropylene amine oxime-single-photon emission computed tomographic testing, including acetazolamide testing of cerebrovascular reactivity, was performed during the second postoperative week for 20 of the 50 patients.

RESULTS

BFVs in basal arteries ipsilateral to the surgical approach increased significantly (P < 0.001) from preoperative baseline values of approximately 52 +/- 13 cm/s (mean +/- standard deviation) to values of approximately 86 +/- 27 cm/s on postoperative Day 3 and reached their maximal values of approximately 115 +/- 37 cm/s after a median of 7 days. BFVs in contralateral vessels exhibited a similar but somewhat attenuated pattern. Hexamethylpropylene amine oxime-single-photon emission computed tomography demonstrated ipsilateral regions of hypoperfusion in 100.0% of the cases and contralateral hypoperfusion in 80.0%. Cerebrovascular reactivity was impaired in 83.3% of the cases ipsilaterally and in 33.3% contralaterally.

CONCLUSION

A significant proportion of patients who undergo microneurosurgical procedures develop bilateral alterations of their cerebral circulation. The elevations in mean BFV values represent cerebral vasospasm. Because these changes remain asymptomatic for the majority of patients, the transsylvian approach can be considered "minimally invasive" but not "atraumatic." Alternative surgical routes and alternative treatment modalities should be investigated in a similar manner.

Transcranial Doppler sonography in children: review of a seven-year experience

AIM

We report the use of transcranial Doppler sonography (TCD) examinations in children (mean age 12.7 years; range 0.5-18 years) without an open fontanelle, using TCD equipment with a 2 MHz pulse wave transducer. Our results over a 7-year period are described.

MATERIAL AND METHODS

A total of 858 children were referred from the paediatric outpatient department. All patients were divided into three groups according to the reason for referral.

RESULTS

We found positive pathological results in the following: (1) headache and orthostatic dysregulation (0.4%, three out of 728); (2) acute neurological symptoms (5.4%, six out of 112); (3) other indications (22.2%, four out of 18). The positive predictive value of finding an abnormality was very low (0.50).

CONCLUSION

TCD examination is ineffective in children with non-specific headache or orthostatic dysregulation due to the specific limitations of this method. We found a higher percentage of abnormal results in children referred for other indications. However, since these children usually undergo MR imaging (and MR angiography, if necessary), in our opinion the TCD examination does not add any additional information. The value of TCD in children is not in the primary diagnosis of disease but in the follow up of known vascular processes (e.g. stenoses) or in chronic diseases including angiitis and sickle cell disease.

Traumatic subarachnoid hemorrhage: demographic and clinical study of 750 patients from the European brain injury consortium survey of head injuries

OBJECTIVE

Previous reports identified the presence of traumatic subarachnoid hemorrhage (tSAH) on admission computed tomographic (CT) scans as an independent prognostic factor in worsening outcomes. The mechanism underlying the link between tSAH and prognosis has not been clarified. The aim of this study was to investigate the association between CT evidence of tSAH and outcomes after moderate or severe head injuries.

METHODS

In a survey organized by the European Brain Injury Consortium, data on initial severity, treatment, and subsequent outcomes were prospectively collected for 1005 patients with moderate or severe head injuries who were admitted to one of the 67 European neurosurgical units during a 3-month period in 1995. The CT findings were classified according to the Traumatic Coma Data Bank classification system, and the presence or absence of tSAH was recorded separately in the initial CT scan forms.

RESULTS

Complete data on early clinical features, CT findings, and outcomes at 6 months were available for 750 patients, of whom 41% exhibited evidence of tSAH on admission CT scans. There was a strong, highly statistically significant association between the presence of tSAH and poor outcomes. In fact, 41% of patients without tSAH achieved the level of good recovery, whereas only 15% of patients with tSAH achieved this outcome. Patients with tSAH were significantly older (median age, 43 yr; standard deviation, 21.1 yr) than those without tSAH (median age, 32 yr; standard deviation, 19.5 yr), and there was a significant tendency for patients with tSAH to exhibit lower Glasgow Coma Scale scores at the time of admission. A logistic regression analysis of favorable/unfavorable outcomes demonstrated that there was still a very strong association between tSAH and outcomes after simultaneous adjustment for age, Glasgow Coma Scale Motor Scores, and admission CT findings (odds ratio, 2.49; 95% confidence interval, 1.74-3.55; P < 0.001). Comparison of the time courses for 164 patients with early (within 14 d after injury) deaths demonstrated very similar patterns, with an early peak and a subsequent decline; there was no evidence of a delayed increase in mortality rates for either group of patients (with or without tSAH).

CONCLUSION

These findings for an unselected series of patients confirm previous reports of the adverse prognostic significance of tSAH. The data support the view that death among patients with tSAH is related to the severity of the initial mechanical damage, rather than to the effects of delayed vasospasm and secondary ischemic brain damage.

Use of transcranial duplex sonography in the treatment of intracranial aneurysms

The use of transcranial duplex sonography in documenting additional findings by measuring vasospasm and visualising aneurysms in neurosurgical patients is described. Daily measurement of vasospasm using this method enables reassessment of the status of the lesion in the context of the patient's clinical condition. This offers a practical alternative to angiographic investigation in aneurysm patients, provided ultrasound penetration of the cranium is optimal.