De novo formation and rupture of an azygos pericallosal artery aneurysm. Case report

Pathogenic Factors and Prognosis of De Novo Aneurysms vAfter Aneurysm Clipping

OBJECTIVE

To confirm this hypothesis, this study aimed to explore the pathogenic factors, prognosis, and their relationship in de novo aneurysms and to reach a consensus on their management.

METHODS

First, the clinical data of 5 patients with de novo aneurysms from April 1998 to October 2021 were analyzed retrospectively. Then, the English literature on de novo aneurysms reported in Pubmed from 1985 to 2021 was systematically reviewed, and 18 case reports from 17 articles and 16 case series were identified. Univariate and multivariate analyses and modified Fisher test were used to analyze the relationship between pathogenic factors and prognosis.

RESULTS

Hypertension was noted in 60% of our clinical cases, 50% of the case series identified in the literature review, and 66.7% of the case reports in the literature review. In the case reports identified from our literature review, the proportion of original aneurysms in the anterior circulation was 96.3%. Moreover, in our 5 cases, all original aneurysms occurred in the anterior circulation. The rupture rate of original aneurysms in our 5 cases was 100%, and that of the cases reported in the literature review was 88.9%. Univariate logistic analysis showed that the time interval was related to the prognosis of de novo aneurysms with a P value of 0.048 and an odds ratio of 0.968 (95% confidence interval 0.938-1.000). Modified Fisher exact tests showed that patient age at the occurrence of de novo aneurysm P = 0.029) was related to the prognosis of de novo aneurysms.

CONCLUSIONS

Hypertension, an original aneurysms located in the anterior circulation and rupture represent the pathogenic factors associated with de novo aneurysms. The time interval to de novo aneurysm and patient age at the occurrence of de novo aneurysm are predictive of prognosis. Based on the above information, we can prevent and improve the prognosis of de novo aneurysms.

A De Novo Aneurysm of the Anterior Cerebral Azygos Artery Following a Middle Cerebral Arterial Aneurysm with Subarachnoid Hemorrhage

A de novo aneurysm of a cerebral artery, defined as a newly growing aneurysm after aneurysmal clipping, but not close to a previously clipped one, is relatively rare. Five studies have reported that the annual incidence of de novo aneurysm formation ranged from 0.3% to 1.8%. A 56-year-old man presented with headache. Magnetic resonance angiography (MRA) and computed tomography (CT) showed an aneurysm with arachnoid hemorrhage located at the left middle cerebral artery (MCA) associated with an azygos anterior cerebral artery (ACA). Eight years later, the patient complained of dizziness, and MRA demonstrated no visualization of the MCA on the left due to metal artifact, but a new lesion, an azygos ACA aneurysm, 9 mm in diameter, was seen. Clipping was performed using multiple clips through the interhemispheric space. Late follow-up examination with MRA or three-dimensional CT to detect de novo aneurysms should be considered in a patient with this vascular anomaly after subarachnoid hemorrhage.

Giant saccular distal azygos artery aneurysm: Report of a case and review of literature

An azygos anterior cerebral artery (ACA) is a rare variant of normal embryogenesis in which confluence of two A1 segments results in a single A2 segment with the absence of anterior communicating artery. The occurrence of an aneurysm at the bifurcation of azygos ACA is rare with few cases reported in the literature. We report a case of a 40-year-old lady who presented with subarachnoid hemorrhage following rupture of a giant, saccular distal azygos ACA aneurysm. Bifrontal craniotomy and clipping of an aneurysm was performed. The clinical significance of azygos ACA and surgical strategies in clipping these aneurysms are discussed with a review of literature.

Rapid aneurysm growth and rupture in systemic lupus erythematosus

BACKGROUND

Subarachnoid hemorrhage (SAH) due to intracranial aneurysm rupture is a major neurosurgical emergency associated with significant morbidity and mortality. Rapid aneurysm growth is associated with rupture. Systemic lupus erythematosus (SLE) is a multi-system autoimmune disorder whose complications can include cerebral vasculitis and vasculopathy. Intracranial aneurysms are not known to occur more frequently in SLE patients than the general population; however, aneurysm growth rates have not been studied in SLE.

CASE DESCRIPTION

We present a 43-year-old female with SLE on prednisone, hydroxychloroquine, and azathioprine with moderate disease activity who presented with severe, acute-onset headache and was found to have Hunt and Hess grade II SAH due to rupture of an 8 mm saccular anterior communicating artery (ACoA) aneurysm. The patient developed severe vasospasm, re-ruptured, and was taken for angiography and embolization, which was challenging due to a high degree of vasospasm and arterial stenosis. Review of imaging from less than 2 years prior demonstrated a normal ACoA complex without evidence of an aneurysm.

CONCLUSION

We review the literature and discuss the risk factors and pathophysiology of rapid aneurysm growth and rupture, as well as the pathologic vascular changes associated with SLE. Although SLE patients do not develop intracranial aneurysm at an increased rate, these changes may predispose them to higher incidence of growth and rupture. This possibility-coupled with increased morbidity and mortality of SAH in SLE-suggests that SAH should be considered in SLE patients presenting with headache, and advocates for more aggressive treatment of SLE patients with unruptured aneurysms.

De Novo Aneurysm: Case Reports and Literature Review

BACKGROUND AND IMPORTANCE:

Formation of cerebral de novo aneurysms (CDNAs) is rare, and the pathogenesis remains obscure. We analyzed factors involved in formation of CDNAs and suggest guidelines for follow-up of patients.

CLINICAL PRESENTATION:

We retrospectively reviewed intracranial aneurysms at our institute and published reports from 1964 to 2008. Eleven patients were found with CDNAs, and 138 patients were collected from the published literature. We assessed the clinical characteristics, such as sex, size, and site of CDNA, past history, and time to occurrence of CDNAs. Of 11 patients, 10 were female and 1 was male; the mean age of the first onset was 53 years (range, 25-69 years). The mean time between first aneurysms and CDNAs was 10.6 years (range, 3-29 years). The most common site of occurrence was anterior circulation. One patient experienced contralateral occurrence, and 2 patients changed from anterior to posterior circulation CDNAs. Six (54.5%) patients had a history of arterial hypertension. Results from analysis of the whole series from the literature revealed that the risk of rupture increased with a previous history of hemorrhage. Contralateral occurrence of CDNAs was related to previous location, and multiplicity, whereas the occurrence of anterior to posterior changes of CDNAs and shorter interval only correlated with an older age group.

CONCLUSION:

Although the formation of CDNAs is rare, several factors may contribute to its occurrence. Female patients with a history of arterial hypertension were at a higher risk for CDNA occurrence. We recommend follow-up imaging studies within 10 years after the initial aneurysms; therefore, at least 50% of CDNAs can be found before rupture.

Management of distal anterior cerebral artery aneurysms: a single institution retrospective analysis (1997-2005)

OBJECTIVE

Our goal was to assess the clinical and angiographic outcomes among patients undergoing treatment for distal anterior cerebral artery aneurysms at the Jefferson Hospital for Neuroscience (1997-2005).

METHODS

Forty-one patients (1.5% of all aneurysms treated) with distal anterior cerebral artery aneurysms had undergone treatment. The clinical and angiographic outcomes of these patients were studied retrospectively using chart reviews, operative reports, and angiographic reports. The mean clinical and angiographic follow-up periods were 16 months (range, 3-74 mo) and 16.5 months (range, 6-81 mo), respectively.

RESULTS

Twenty-eight (68%) patients had undergone endovascular embolization (22 women, six men; mean age, 58.2 yr), whereas 13 (32%) had undergone microsurgery for clip ligation (six men, seven women; mean age, 47.4 yr). Within the coiled group, 50% of the patients belonged in the Hunt and Hess (HH) III and IV groups, whereas 46.2% of the patients in the clipped group were elective patients (HH Grade 0). The mean aneurysmal sizes among the clipped and coiled groups were 4.9 and 5.5 mm, respectively. Among the clipped patient population, 100% of the patients had successful clip ligation as evidenced by intraoperative cerebral angiography, there was a 0% recurrence rate among the two patients who have had long-term follow-up, 0% recurrent subarachnoid hemorrhage, and 92% patients achieved a modified Glasgow Outcome Scale score of I to II. Among the coiled patient population, there was an 89% rate of successful embolization, 18% recurrence rate, 0% recurrent subarachnoid hemorrhage, and 64% achieved a modified Glasgow Outcome Scale score of I to II. None of the patients had clinically symptomatic vasospasm. A strong correlation existed between having a ventriculostomy and requiring a shunt in patients with HH Grade IV compared with patients in HH Grades I through III.

CONCLUSION

In our analysis, clinical outcomes were better in the clipped group; however, the differences are not statistically significant (P = 0.3675) and are explained by the selection bias. Statistically significant predictors of outcomes were age (<60 yr), size of the aneurysm (>5 mm), absence of ventriculostomy, and presenting HH grade.

Saccular aneurysm of the azygos anterior cerebral artery: three case reports

The azygos anterior cerebral artery, a rare anomaly in the circle of Willis in which only a single vessel supplies the medial aspects of both anterior cerebral hemispheres, is closely associated with saccular aneurysms. We present three cases of azygos anterior cerebral artery aneurysms among the 781 cerebral aneurysms surgically treated at our institution in an 11-year period. These three cases all involved elderly women who presented with subarachnoid hemorrhage. Conventional cerebral angiography and CT angiography revealed small saccular aneurysms at the distal ends of the azygos anterior cerebral arteries. These aneurysms were clipped successfully using a bifrontal interhemispheric approach. Hence, the pathogenesis of these particular aneurysms relating to hemodynamic change, associated anomalies, and surgical pitfalls is discussed with review of literature.

Visualizing the Dynamics of Cerebral Aneurysms with Four-dimensional Computed Tomographic Angiography

OBJECTIVE

This study was designed to assess cerebral aneurysm hemodynamics with four-dimensional (4-D) computed tomographic (CT) angiography.

METHODS

Multislice computed tomography with a retrospective electrocardiography-gated reconstruction algorithm was used. The motions of the aneurysmal wall, bleb, and dissecting cavity were rendered observable in a 4-D CT movie.

RESULTS

The findings for 30 patients with 34 aneurysms who underwent 4-D CT angiography were analyzed. Twenty-three aneurysms were documented in the anterior circulation region, and the remaining 11 aneurysms were in the posterior circulation. The average aneurysm size was 6.4 mm, and there were five large aneurysms. There were 28 saccular, 4 dissecting, and 2 fusiform aneurysms. 4-D CT movies were obtained successfully in all aneurysms. The aneurysm wall motion of two growing aneurysms exhibited a highly irregular pulsation in the 4-D CT movie. Pulsating blebs were detected in nine (32.1%) of the saccular aneurysms. In two patients with subarachnoid hemorrhage, preoperative 4-D CT angiography revealed dangerous pulsating blebs that were confirmed as the ruptured points during the surgical procedure. Specifically, in the dissecting aneurysms, the 4-D CT movie revealed a pulsating line, which provided accurate and detailed information regarding the dissecting cavity and intimal flap. The dissecting cavity revealed by the 4-D CT movie could not be detected with conventional or three-dimensional digital subtraction angiography. The 4-D CT movie images were highly useful in making anatomic judgments for the endovascular surgery procedure.

CONCLUSION

4-D CT images are valuable in determining aneurysmal wall dynamics. Highly useful information was obtained regarding intracranial aneurysms with 4-D CT angiography compared with other modalities. Further studies will be necessary to elucidate the optimal application of this new technology to both the pathological characteristics and therapeutic amelioration of aneurysmal features such as dome pulsation, blebs, and growing aneurysms.

Nonsaccular aneurysms of the azygos anterior cerebral artery

Object

The azygos or undivided anterior cerebral artery (ACA) is a rare variant, and aneurysms associated with this variant are particularly rare. Most reported azygos ACA aneurysms are saccular, but the authors encountered four patients with this variant who had nonsaccular aneurysms. A review of the management of these lesions and this morphological distinction is presented.

Methods

A retrospective review of patients with aneurysms treated over a 6-year period identified five Type I (according to the Baptista classification) azygos ACA lesions, of which four were nonsaccular. Aneurysms associated with other ACA variants (Baptista Types II and III) were excluded.

Azygos ACA aneurysms accounted for 0.5% of all treated lesions and 1.7% of all ACA and anterior communicating artery aneurysms. One lesion in this series was located proximally at the azygos ACA origin, and three were located distally. All four aneurysms were large (>10 mm in diameter), and two were thrombotic. All aneurysms were treated with microsurgical clip occlusion.

Conclusions

Azygos ACA aneurysms are rare, and may have unusual nonsaccular anatomy (for example, fusiform shape, broad base, complex branching, and/or thrombus in the lumen). The nonsaccular morphology of these aneurysms may render them unsuitable for endovascular coil placement, and may complicate their microsurgical management.

Ruptured aneurysm arising from the proximal end of an azygos anterior cerebral artery--case report

A 59-year-old woman presented with subarachnoid hemorrhage. Conventional angiography and three-dimensional computed tomography (3-D CT) angiography showed a saccular aneurysm at the junction of the azygos anterior cerebral artery (ACA) and the left A1 segment. This aneurysm was associated with a fenestration of the right hypoplastic A1 segment. The aneurysm neck was completely clipped, preserving the azygos ACA and other perforators. Aneurysm of the azygos ACA is almost always located at the distal bifurcation, and rarely at the proximal end. Proximal azygos ACA aneurysm can mimic anterior communicating artery aneurysm. Therefore, accurate preoperative diagnosis is critical using 3-D CT angiography as well as conventional angiography, and close follow up of patient is necessary to monitor for development of a de novo aneurysm at the distal bifurcation of the azygos ACA.

Giant aneurysm of the azygos pericallosal artery: case report and review of the literature

BACKGROUND

Pericallosal aneurysms are encountered less than 6.7%, and giant aneurysms among them even less. Giant azygos pericallosal artery aneurysm at the callosomarginal bifurcation is extremely rare, and our case presented herein is the second one. The case is discussed with thorough review of the literature.

METHODS

A 65-year-old woman presented with an extremely rare giant aneurysm on the azygos pericallosal artery manifesting as subarachnoid hemorrhage in World Federation of Neurosurgical Societies Grade 3. Computed tomography (CT), magnetic resonance angiography (MRA), and four vessel angiography revealed a giant azygos pericallosal artery aneurysm associated with a second aneurysm at the left M1.

RESULTS

After recovery to Grade 2, she underwent surgery via the right frontal interhemispheric approach for the azygos artery aneurysm on the 17th day after bleeding. The true dimensions of the aneurysm were greater than indicated by angiography because of partial thrombosis. Trilobulate aneurysm was carefully dissected from the surrounding structures. Postoperative cerebral angiography showed no filling of the clipped aneurysm and preservation of circulation.

CONCLUSIONS

The treatment of distal anterior cerebral artery aneurysms is often difficult, because of their broad-based irregular configurations and adherence to surrounding tissue, tendency to bleed irrespective of size and the coexistence of other cerebral aneurysms. However, excellent outcomes can be obtained based on thorough preoperative radiologic evaluation, including magnetic resonance imaging (MRI), and correct selection of surgical approach.

Variaciones del sector anterior del polígono de Willis. Correlación anatomo-angiográfica y su implicancia en la cirugía de aneurismas intracraneanos (Arterias: ácigos cerebral anterior, mediana del cuerpo calloso y cerebral media accesoria)

It is worlwide accepted that in almost 60% of cases, anatomical variants in the Circle of Willis can be found. Some of them are associated with vascular malformations such as aneurysms. The knowledge of these anatomical variants is of vital importance when facing surgery, being the aims to preserve arteries in unusual localisations, which when injured can determine invalidating sequelae. The authors have reviewed 192 cerebral hemispheres, finding three variants in the anterior Circle of Willis: Azigos anterior cerebral artery; Median artery of the corpus callosum and accessory middle cerebral artery. The authors make an anatomical description of the findings, their angiographical correlation, and describe the influence of these changes during surgery of aneurysms in the involved regions.

De novo formation and rupture of an aneurysm

✓ The authors describe a case of de novo formation and rupture of an aneurysm located at the junction of the left internal carotid artery and the superior hypophyseal artery in a middle-aged woman 2 months after another aneurysm, located on the anterior communicating artery, had been clipped. This case is rare because of the short interval between the last angiographic study performed at the first operation and the diagnosis of the de novo aneurysm; in this case the interval was only 47 days, compared with other cases in the literature in which the intervals were 3 to 34 years. Aneurysms can enlarge considerably in 2 to 4 weeks and can rupture at or soon after their formation. This case provides insight into aneurysm formation and rupture.