Selective internal carotid artery cross-clamping increases the specificity of cerebral oximetry for indication of shunting during carotid endarterectomy.

BACKGROUND: An indication for selective shunting during carotid endarterectomy (CEA) is based on monitoring during a procedure. Cerebral oximetry (CO) using near-infrared spectroscopy (NIRS) may be a simple technique, but its relevance during CEA, especially with respect to cutoff values indicating shunt implantation, still needs to be elucidated. METHODS: One hundred twenty five patients underwent CEA under local anesthesia (LA) and were monitored clinically throughout the whole procedure. The patients were also monitored using bilateral NIRS probes during surgery. The NIRS values were recorded and evaluated before and after selective cross-clamping, firstly by the external carotid artery (ECA), followed by the internal carotid artery (ICA). The decrease in the ipsilateral CO values, with respect to the indication of shunting, was only analyzed after selective cross-clamping of the ICA. The decision to use an intraluminal shunt was solely based on the neurological status evaluation after ICA cross-clamping. RESULTS: One hundred five patients (85%) were stable throughout the CEA, while 20 patients (15%) clinically deteriorated during surgery. The mean drop in the CO after selective ICA clamping in clinically stable patients was 6%, while in patients with clinical deterioration, the NIRS decreased by 14.5% (p < 0.05). When the cutoff value for selective shunting was set as a 10% decrease of the ipsilateral CO after selective ICA clamping, the sensitivity of the technique was 100% and the specificity 83.0%. CONCLUSIONS: Our study showed that a 10% decrease in the ipsilateral brain tissue oximetry after selective cross-clamping the ICA provides a reliable cutoff value for selective shunting during CEA. Despite the availability of a variety of monitoring tools, the NIRS may be an easy, reliable option, especially in the scenario of acute CEA in general anesthesia.

Hemodynamic changes in a middle cerebral artery aneurysm at follow-up times before and after its rupture: a case report and a review of the literature.

Hemodynamic parameters play a significant role in the development of cerebral aneurysms. Parameters such as wall shear stress (WSS) or velocity could change in time and may contribute to aneurysm growth and rupture. However, the hemodynamic changes at the rupture location remain unclear because it is difficult to obtain data prior to rupture. We analyzed a case of a ruptured middle cerebral artery (MCA) aneurysm for which we acquired imaging data at three time points, including at rupture. A patient with an observed MCA aneurysm was admitted to the emergency department with clinical symptoms of a subarachnoid hemorrhage. During three-dimensional (3D) digital subtraction angiography (DSA), the aneurysm ruptured again. Imaging data from two visits before rupture and this 3D DSA images at the moment of rupture were acquired, and computational fluid dynamic (CFD) simulations were performed. Results were used to describe the time-dependent changes of the hemodynamic variables associated with rupture. Time-dependent hemodynamic changes at the rupture location were characterized by decreased WSS and flow velocity magnitude. The impingement jet in the dome changed its position in time and the impingement area at follow-up moved near the rupture location. The results suggest that the increased WSS on the dome and increased low wall shear stress area (LSA) and decreased WSS on the daughter bleb with slower flow and slow vortex may be associated with rupture. CFD performed during the follow-up period may be part of diagnostic tools used to determine the risk of aneurysm rupture.

Microsurgery and endovascular treatment of posterior inferior cerebellar artery aneurysms.

Aneurysms located on the posterior inferior cerebellar artery are rare, and treatment guidelines for them have not yet been established. In this paper, we present the results of a retrospective study which analyzes the management and treatment of 15 patients with posterior inferior cerebellar artery aneurysms from 2004 to 2013. The aneurysms were ruptured and presented with a subarachnoid hemorrhage. Of the 15 aneurysms, ten were of saccular, three fusiform, and two were dissecting. Computed tomography angiography or digital subtraction angiography revealed other aneurysms or intracerebral artery hypoplasia in seven patients. Either surgical or endovascular treatment was performed depending on the localization and morphology of the aneurysm. Six aneurysms were coiled, and surgery was performed in nine cases. Of the nine surgically treated patients, six (75%) had good outcomes. Of the six patients treated using endovascular procedures, three patients (50%) recovered. Patient outcomes were classified using the Hunt&Hess scale. Patients with Hunt&Hess 1-3 recovered without a neurological deficit. On the other hand, patients with Hunt&Hess 4-5 had a risk of up to 93% of death or a poor outcome. In two cases of endovascular and in two cases before any therapy, aneurysmal rebleeding occurred and resulted in deterioration of clinical state of the patient and a poor prognosis with high risk of death. This study shows the necessity of acute treatment of posterior inferior cerebellar artery aneurysm, of thorough diagnostic, and of interdisciplinary cooperation.