Morphological, hemodynamic, and clinical independent risk factors for anterior communicating artery aneurysms.

BACKGROUND AND PURPOSE: The pathogenesis of cerebral aneurysms still raises some controversies. The aim of this study was to identify morphological, hemodynamic, and clinical independent risk factors for anterior communicating artery (ACoA) aneurysm development. METHODS: Computed tomography angiography and transcranial color-coded sonography were performed in 77 patients with a nonbleeding ACoA aneurysm and in 73 controls. Symmetry of A1 segments of the anterior cerebral arteries, angles between A1 and A2 segments, tortuosity, diameter, mean velocity (Vm), pulsatility index, and volume flow rate in both A1 segments were determined. Moreover, all study participants completed a survey on their medical history. Multivariate backward stepwise logistic regression analysis was performed to identify independent risk factors for ACoA aneurysm development. RESULTS: Smoking, hypertension, asymmetry of A1 segments, the angle between A1 and A2 segments, A1 segment diameter, Vm, pulsatility index, and volume flow rate turned out to be associated with the occurrence of ACoA aneurysms on univariate analysis. Multivariate analysis identified smoking (odds ratio, 2.036; 95% confidence interval, 1.277-3.245), asymmetry of A1 segments>40% (odds ratio, 2.524; 95% confidence interval, 1.275-4.996), pulsatility index (odds ratio, 0.004; 95% confidence interval, 0.000-0.124), and the angle between A1 and A2 segments≤100° (odds ratio, 4.665; 95% confidence interval, 2.247-9.687) as independent strong risk factors for ACoA aneurysm development. CONCLUSIONS: The risk of ACoA aneurysm formation is determined by several independent clinical, morphological, and hemodynamic factors. The strongest independent risk factors include smoking, asymmetry of A1 segments>40%, low blood flow pulsatility, and the angle between A1 and A2 segments≤100°.

Transcranial color-coded Doppler assessment of cerebral arteriovenous malformation hemodynamics in patients treated surgically or with staged embolization.

OBJECTIVE: The etiology of hemodynamic disturbances following embolization or surgical resection of arteriovenous malformations (AVMs) has not been fully explained. The aim of the study was the assessment of the selected hemodynamic parameters in patients treated for cerebral AVMs using transcranial color-coded Doppler sonography (TCCS). MATERIALS AND METHODS: Forty-six adult patients (28 males, 18 females, aged 41 ± 13 years, mean ± SD) diagnosed with AVMs who were consecutively admitted to the Department of Neurosurgery between 2000 and 2012 treated surgically or with staged embolization were enrolled in the study. All patients were examined with TCCS assessing mean flow velocity (Vm), the pulsatility index (PI) and vasomotor reactivity (VMR) in all main intracranial arteries. The examined parameters were assessed in the vessel groups (feeding, ipsilateral and contralateral to the AVM) and they were compared between the examinations, i.e. at admission, within 24h after the first embolization or surgical resection (I control), and before the second embolization (II control). RESULTS: In feeders which were completely obliterated or surgically resected--I control examination showed a nonsignificant Vm decrease. The difference between Vm before embolization and II control examination was significant (102.0 ± 47.8 cm/s vs 54.3 ± 19.4 cm/s, p<0.01). A significant increase in PI (0.72 ± 0.18 vs 0.94 ± 0.24, p<0.01) and VMR (1.80 ± 0.59 vs 2.78 ± 0.78, p<0.01) of feeding vessels was observed in I control. No further increase in PI or in VMR was observed. In embolized feeding vessels after partial AVM embolization I control examination showed a significant decrease in Vm (116.1 ± 32.6 cm/s vs 93.4 ± 33.0 cm/s, p<0.01). No further significant decrease in Vm was noted. The pulsatility index increased significantly (I control, 0.54 ± 0.11 vs 0.66 ± 0.15, p<0.01) and then decreased nonsignificantly (II control). No statistically significant differences were found in VMR values between pretreatment, I and II control examinations. Both Vm in the ipsilateral internal carotid artery and the ratio of Vm of the embolized vessel to Vm of the corresponding contralateral vessel were significantly higher in I control examination compared to II control examination (111.8 ± 44.0 cm/s vs 101.3 ± 40.6 cm/s, p<0.01; 1.63 ± 0.61 vs 1.37 ± 0.62, p<0.01; respectively). No statistically significant correlation was observed between the decrease in Vm or the increase in PI in the embolized vessels and the reduction of AVM volume. In the nonembolized feeding vessels after partial AVM embolization II control examination revealed the increase in Vm and a significant decrease in PI (0.71 ± 0.21 vs 0.62 ± 0.16, p<0.01) compared to I examination. No statistically significant changes in the VMR value in the nonembolized feeders between the pretreatment, I and II control examinations were noted. CONCLUSIONS: The decrease in Vm and the increase in the PI in the embolized feeding vessels after the first complete embolization or surgical resection is observed, whereas the PI returned to normal values before Vm does. The observed decrease in Vm and an increase in the PI in embolized AVM feeders after complete or partial embolization do not correlate with the extent of embolization. In these vessels a relative increase in blood flow velocity is maintained within the first 24h following embolization as compared to contralateral vessels. The increase in Vm is not related to disturbances in VMR. Blood redistribution to the nonembolized AVM feeders is observed after partial AVM embolization.

Blood flow velocity in the arteries of the anterior cerebral artery complex in patients with an azygos anterior cerebral artery aneurysm: a transcranial color-coded sonography study.

OBJECTIVE: It is presumed that increased blood flow through the single azygos anterior cerebral artery (Az) may contribute to the formation of an Az aneurysm. The aim of this study was to assess the blood flow velocities in the arteries of the anterior cerebral artery (ACA) complex in patients with the Az aneurysm. PATIENTS AND METHODS: A series of three patients (2 men, aged: 65, 52 and 41) with an aneurysm (unruptured in two cases) of the distal Az was examined. Blood flow velocities in the Az and the A1 segment of the ACA were measured by means of a transcranial color-coded duplex sonography (TCCS) and the Az to A1 segment (Az/A1) velocity ratio was calculated. The control group consisted of 22 healthy subjects (mean age: 44 years). RESULTS: There was a trend toward decreased (p=0.06) mean blood flow velocity in the Az compared to the A2 segment of the ACA of the control group. Blood velocity in the A1 segment did not differ between the study and control groups. Pulsatility and resistance indices in the Az were similar to those in the A2 segment of the control group. There were no differences between the Az/A1 ratio in the study group and the A2/A1 velocity ratio in the control group. CONCLUSION: Our results suggest that Az aneurysms are not associated with increased blood flow velocity in the Az. Possibly, a hemodynamic stress related to the Az bifurcation geometry, together with a bent course of this artery around the genu of the corpus callosum, predispose to aneurysm formation.

[Treatment of deep brain arteriovenous malformations]. / Leczenie glebokich naczyniaków tetniczo-zylnych mózgu.

BACKGROUND AND PURPOSE: The results of the treatment of patients with deep, supratentorial arteriovenous malformations (AVMs) located in medial hemisphere or intraventricularly are presented. MATERIAL AND METHODS: The paper presents the results of treatment of 17 patients. AVMs were located in the trigonum of the lateral ventricle in 4 cases (23.5%), in the splenium of the corpus callosum and its neighborhood in 4 cases (23.5%), in the parahippocampal and lingual gyrus in 3 cases (17%), in the head of the caudate nucleus in 2 cases (12%), in the hippocampus and the nucleus amygdalae in 2 cases (12%), in the anterior part of the gyrus cinguli in 1 case (6%) and in the truncus of the corpus callosum in 1 case (6%). RESULTS: AVMs most often manifested as intracerebral or subarachnoid hemorrhage (82%). The surgical treatment has been applied (total removal--90%), embolization with histoacryl glue (total embolization--20%) and irradiation with LINAC. The surgical treatment was performed in all patients with hemiparesis and intracerebral hematomas. CONCLUSION: The results of the surgical treatment are good and it fastest prevents recurrent hemorrhage from deep AVM. Incomplete embolization of AVM without the surgical treatment or radiosurgery is life threatening for the patients.