Hemodynamic effects of developmental venous anomalies with and without cavernous malformations

BACKGROUND AND PURPOSE

Association between developmental venous anomalies is well known, but remains unexplained. Our aim was to study possible hemodynamic differences around developmental venous anomalies with and without cavernous malformations.

MATERIALS AND METHODS

In this prospective study approved by the institutional review board, PWI was performed in 24 patients with 25 DVAs (10 with and 15 without CMs) who consented to participate. We calculated relative cerebral blood volume, relative cerebral blood flow, and relative mean transit time for the brain surrounding the DVA tributaries in reference to contralateral mirror image locations. Corresponding control values (cCBV, cCBF, and cMTT) were generated in a similar fashion for remote ipsilateral regions with normal venous drainage, also in reference to contralateral mirror image locations. Perfusion parameters for DVAs and control regions were tested for differences between groups with the t test for independent or paired samples (or the nonparametric equivalents). Similar testing was done for perfusion parameters for DVAs with and without CMs.

RESULTS

Normal-appearing brain surrounding DVAs showed increased rCBV (median = 2.98; range = 1.39-6.61), increased rCBF (median = 2.00, range = 0.79-4.43), and increased rMTT (mean = 1.46; 95% confidence interval, 1.32-1.59). These were significantly higher than median cCBV (0.99; 95% confidence interval, 0.89-1.06; P < .01), median cCBF (1.00; 95% confidence interval, 0.94-1.27; P < .01), and mean cMTT (1.00; 95% confidence interval, 0.98-1.02; P < .01), respectively. Mean rMTT (1.70; 95% confidence interval, 1.46-1.93) for DVAs with CMs was higher than mean rMTT (1.29; 95% confidence interval, 1.19-1.40; P < .01) for DVAs without CMs.

CONCLUSIONS

DVAs are strongly associated with altered hemodynamics. Significant differences in these hemodynamic alterations for DVAs with and without CMs suggest their possible role in the formation of CMs.

Retrospective review of cerebral mycotic aneurysms in 26 patients: focus on treatment in strongly immunocompromised patients with a brief literature review

BACKGROUND AND PURPOSE

Cerebral mycotic aneurysms are a rare and deadly type of aneurysm that have no definitive treatment guidelines. Our purpose was to retrospectively review known or suspected cases of CMA in order to identify patient populations that may be associated with higher morbidity and mortality. We hope that the identification of patients with these risk factors will lead to early stratification upon presentation, and more urgent treatment of their CMAs. We also hoped to identify any benefit or complication that was specific to either the endovascular or neurosurgical repair of CMAs.

MATERIALS AND METHODS

A retrospective multi-institutional study was performed examining cases of CMA during a 15-year period. Patients were considered strongly immunocompromised if there were long-term severely immunocompromised states: AIDS, chemotherapy, or steroid immunosuppression. Patients were excluded if angiographic findings suggested an alternative diagnosis or if an infectious etiology was unknown. Antibiotics were considered "noninvasive treatment." Endovascular and neurosurgical repair were considered "invasive treatment." Data were recorded by reviewing electronic medical records and imaging reports.

RESULTS

Twenty-six patients with 40 CMAs were included. Three patients were considered strongly immunocompromised and presented with 4 CMAs, which demonstrated larger average size and more rapid growth; 3 of these patients' aneurysms were treated invasively in the acute period, with the one that was not ruptured causing death. Technical success (aneurysm occlusion without rupture or recanalization) and clinical success (no neurologic complication attributable to the intervention) were obtained equally endovascularly and neurosurgically. Clipping was aborted in favor of coiling for 1 patient. Anticoagulation needed reversal before 2 patients underwent craniotomy for clipping after valve replacement. For CMAs treated with antibiotics alone with angiographic follow-up (n=11), initial aneurysm size was unrelated to persistence and 64% completely regressed.

CONCLUSIONS

We recommend initial invasive treatment for CMAs in strongly immunocompromised patients. Testing for underlying immunocompromised states is warranted in patients with CMAs. Endovascular treatment is favored over neurosurgical treatment in patients requiring acute cardiac valve repair due to delays with anticoagulation reversal.

The current surgical management of intracranial aneurysms

For more than two decades, surgical clipping of ruptured intracranial aneurysms was considered the stan-dard of care. However, as technology improved, a new treatment option was developed, endovascular emoblization. The treatment of cerebral aneurysms, is now in an era where deciding when to clip versus coil can be difficult. Today's cerebrovascular specialist must consider a multitude of factors when developing the best treatment strategy for an individual patient. Optimal management requires a thorough understanding of the natural history of aneurysms as well as risks and benefits related to the different treatment modalities. The purpose of this article is not to proclaim one treatment better than the other, but rather to provide the reader with an up-to-date, comprehensive insight into the management of cerebral aneurysms. We will review data regarding the natural history of aneurysms along with the effectiveness of both surgical clipping and endovascular embolization. We will further discuss our current management strategy for some of the most common aneurysms encountered. The successful treatment of intracranial aneurysms requires a multidisciplinary approach, where surgery and endovascular therapies are viewed as complimentary instead of competing.

Neurofilament light chain levels in ventricular cerebrospinal fluid after acute aneurysmal subarachnoid haemorrhage

PURPOSE

The contribution of axonal injury to brain damage after aneurysmal subarachnoid haemorrhage (aSAH) is unknown. Neurofilament light chain (NF-L), a component of the axonal cytoskeleton, has been shown to be elevated in the cerebrospinal fluid of patients with many types of axonal injury. We hypothesised that patients with aSAH would have elevated cerebrospinal fluid (CSF) NF-L levels and sought to explore the clinical correlates of CSF NF-L dynamics.

METHODS

Serial ventricular CSF (vCSF) samples were collected from 35 patients with aSAH for up to 15 days. vCSF NF-L measurements were determined by enzyme-linked immunosorbent assay. NF-L levels were analysed in relation to acute clinical status, radiological findings and 6-month outcomes.

RESULTS

vCSF NF-L concentrations were elevated in all patients with aSAH. Patients with early cerebral ischaemia (ECI), defined as a CT hypodense lesion visible within the first 3 days, had higher acute vCSF NF-L levels than patients without ECI. These elevated NF-L levels were similar in patients with ECI associated with intracranial haemorrhage and ECI associated with surgical/endovascular complications. vCSF NF-L levels did not differ as a function of acute clinical status, clinical vasospasm, delayed cerebral ischaemia or 6-month Glasgow Outcome Scale.

CONCLUSIONS

Elevated vCSF NF-L levels may in part reflect increased injury to axons associated with ECI. However, our results suggest that axonal injury after aSAH as reflected by release of NF-L into the CSF may not play a major role in either secondary adverse events or long-term clinical outcomes.

Zinc translocation accelerates infarction after mild transient focal ischemia

Excess release of chelatable zinc (Zn(2+)) from central synaptic vesicles may contribute to the pathogenesis of selective neuronal cell death following transient forebrain ischemia, but a role in neurodegeneration after focal ischemia has not been defined. Adult male Long-Evans rats subjected to middle cerebral artery occlusion (MCAO) for 30 min followed by reperfusion developed delayed cerebral infarction reaching completion 3 days after the insult. One day after the insult, many degenerating cerebral neurons exhibited increased intracellular Zn(2+), and some labeled with the antibody against activated caspase-3. I.c.v. administration of the Zn(2+) chelator, EDTA saturated with equimolar Ca(2+) (CaEDTA), 15 min prior to ischemia attenuated subsequent Zn(2+) translocation into cortical neurons, and reduced infarct volume measured 3 days after ischemia. Although the protective effect of CaEDTA at this endpoint was substantial (about 70% infarct reduction), it was lost when insult severity was increased (from 30 to 60 min MCAO), or when infarct volume was measured at a much later time point (14 days instead of 3 days after ischemia). These data suggest that toxic Zn(2+) translocation, from presynaptic terminals to post-synaptic cell bodies, may accelerate the development of cerebral infarction following mild transient focal ischemia.

Neuronal apoptosis after CNS injury: the roles of glutamate and calcium

While a role has been well established for excitotoxic necrosis in the pathogenesis of traumatic or ischemic damage to the CNS, accumulating evidence now suggests that apoptosis may also be a prominent contributor. In this review we focus on the role of glutamate and attendant intracellular calcium influx in triggering or modifying excitotoxic necrosis and apoptosis, raising the possibility that calcium influx may affect these two death pathways in opposite directions. Incorporating consideration of both pathways will probably be needed to develop the most effective neuroprotective treatments for CNS injury.

The changing landscape of ischaemic brain injury mechanisms

Thrombolysis has become established as an acute treatment for human stroke. But despite multiple clinical trials, neuroprotective strategies have yet to be proved effective in humans. Here we discuss intrinsic tissue mechanisms of ischaemic brain injury, and present a perspective that broadening of therapeutic targeting beyond excitotoxicity and neuronal calcium overload will be desirable for developing the most effective neuroprotective therapies.

Surgical treatment of paraclinoid and ophthalmic aneurysms

Paraclinoid aneurysms include those arising from the ophthalmic segment and from the distal cavernous carotid artery or clinoid segment. Three aneurysm variants originate from the ophthalmic segment: ophthalmic artery, superior hypophyseal artery, and dorsal types. Clinoidal segment aneurysms arise from the carotid artery in the interval between the carotid oculomotor membrane proximally and the dural ring distally, and include anterior-lateral and medial variants. With proper exposure and a firm understanding of the parasellar osseous, dural, and vascular anatomy, most paraclinoid aneurysms are occluded with low risk to the brain or visual apparatus.