Rapid presentation of a de novo intracranial aneurysm: illustrative case.

BACKGROUND: Intracranial aneurysms are prevalent, particularly with advancing age. De novo aneurysms, occurring independently from the initial lesion, pose a unique challenge because of their unpredictable nature. Although risk factors such as female sex, smoking history, and hypertension have been proposed, the mechanisms underlying de novo aneurysm development remain unclear. OBSERVATIONS: A 79-year-old female developed a de novo saccular aneurysm within a year after management of a ruptured vertebral artery dissecting aneurysm. Her complex clinical course involved subarachnoid hemorrhage with diffuse vasospasm, stent occlusion of a dissecting aneurysm, discovery of a right 7- to 8-mm de novo middle cerebral artery aneurysm at the 1-year magnetic resonance angiography follow-up, and successful coil embolization. LESSONS: This rare occurrence challenges established timelines, as most de novo aneurysms manifest over a longer interval. Studies have attempted to identify risk factors, yet consensus remains elusive, particularly regarding the influence of treatment modality on de novo formation rates. This unique case urges reconsideration of posttreatment surveillance protocols, proposing shorter intervals for imaging and more vigilant follow-up strategies to detect asymptomatic de novo aneurysms. Timelier identification could significantly impact patient outcomes by averting potential ruptures. This emphasizes the need for further research to delineate effective monitoring and preventive measures for these enigmatic lesions.

Risk of de novo aneurysm formation in patients previously diagnosed with a ruptured or unruptured aneurysm: 18-year follow-up.

BACKGROUND: Data on de novo aneurysm formation after treatment for intracranial aneurysms remains scarce. We studied the incidence of de novo aneurysm formation in patients who had undergone aneurysm treatment more than 18 years prior to follow-up. As it is a disease affecting a younger patient population more specific guidelines are needed when planning a follow-up regime. METHODS: The rate of de novo aneurysm formation was assessed with Magnetic Resonance Angiography (MRA) follow-up >18 years after endovascular or microsurgical treatment for an intracranial aneurysm. Variables associated with de novo aneurysm formation were studied using logistic regression. Missing data were imputed using chained random forests. A data-driven model for the prediction of de novo aneurysm was created to calculate the relative variable importance of ten clinical features. RESULTS: De novo aneurysms were identified in 11/81 (13.6 %) patients, of whom 1 was male, over a median follow-up of 20 years. Sex was the most important variable associated with de novo aneurysm formation. Regarding the development of de novo aneurysm, men displayed an odds ratio (OR) of 0.16 (0.01-0.97), compared with women. OR for mRS score 2 or more was 0.20 (95 % CI 0.01-1.34), and OR for smokers was 3.70 (0.54-31.18). Six out of 11 patients (54.5 %) needed treatment; 1 underwent endovascular treatment (EVT) and 5 underwent microsurgical treatment (MST). The overall annual de novo aneurysm formation rate was 0.92 %. CONCLUSIONS: This study highlights the need for a longer follow-up imaging monitoring of patients that have previously undergone treatment for an intracranial aneurysm. These data are useful to take into consideration when planning a follow-up strategy.

Perioperative and long-term complications following therapeutic internal carotid artery occlusion.

BACKGROUND: Parent artery occlusion (PAO) is an effective treatment for hemorrhagic diseases associated with the internal carotid artery. There are several reports of long-term cerebral infarction or the formation of de novo cerebral aneurysms following PAO. MATERIALS AND METHODS: We retrospectively reviewed these complications in 38 patients who underwent PAO for therapeutic treatment. We investigated perioperative cerebral infarctions, long-term cerebral infarctions, and de novo aneurysms. RESULTS: The mean age of the patients was 64.0 years, and 25 patients (65.8%) were female. The causative diseases were unruptured (n = 19; 50.0%) and ruptured (n = 8; 21.1%) aneurysms. PAO was performed after ischemic tolerance was assessed with balloon test occlusion (BTO), and BTO was performed in 34 patients, of whom 25 (73.5%) had ischemic tolerance. Twenty-six patients (68.4%) were treated with PAO alone, eight (23.5%) with low-flow bypass, and six (17.6%) with high-flow bypass. Perioperative complications occurred in five patients (13.2%): two of the 26 patients (7.7%) who underwent scheduled treatment and three of the 12 patients (25.0%) who underwent emergency treatment. One patient (2.6%) had long-term de novo aneurysm, and none developed cerebral infarction. CONCLUSIONS: These results showed that the assessment of ischemic tolerance by performing BTO and appropriate revascularization in scheduled treatments are important to reduce perioperative and long-term cerebral infarctions. PAO must be performed with greater caution in emergency treatment.

An interesting case of survival to multiple ruptures of aneurysms, with persistent trigeminal artery, cranial nerve deficit, and evolutionary exposure of neurovascular treatment.

Subarachnoid hemorrhage secondary to rupture of an aneurysm is a severe condition, associated with a high rate of morbidity and mortality. There are few cases in the literature of rupture of an aneurysm of the persistent trigeminal artery. This is the case of a 62-year-old female who has suffered multiple ruptures of aneurysms, in different decades of her life, with the development of de novo aneurysm, been this the presented case, a rupture of aneurysm of the persistent trigeminal artery. This patient has survival to these conditions and remain without important morbidity. The case manifested with a clinical picture of third and seventh cranial nerve deficit, which this last one, there are not previous publications of cases with this deficit. This aneurysm was embolized with coils, and the postoperative condition was satisfactory, been discharged at 4 postoperative days.

Risk factor management matters more than pharmaceutical cyclooxygenase-2 inhibition in the prevention of de novo intracranial aneurysms.

BACKGROUND AND PURPOSE: Pathophysiological studies of saccular intracranial aneurysm (sIA) disease have shown that inflammation plays a crucial role in sIA development. Pharmaceutical inhibition of COX-2-PGE2-NF-κB signaling (COX-2, cyclooxygenase-2; PGE2, prostaglandin E2; NF-κB, nuclear factor κB) has been shown in animal models to inhibit sIA formation and progression suggesting that use of medication inhibiting COX-2 could reduce intracranial aneurysm formation also in patients. METHODS: The impact of COX-2 inhibition on de novo sIA formation was studied in two cohorts: in a previously described angiographically followed cohort of 1419 sIA patients and in a cohort of 117 sIA patients treated with stenting or stent-assisted embolization. Patients were identified from our population-based Kuopio Intracranial Aneurysm Database. Data on the use of anti-inflammatory medications and hospital diagnoses were obtained from national registries. Risk factors were identified by univariate and multivariate analyses. RESULTS: De novo sIA patients were younger and more often smokers. Use of COX-2 selective inhibitors or nonsteroidal anti-inflammatory drugs did not significantly reduce de novo sIA formation, but the percentage of patients with de novo sIA formation was smaller in patients with prescribed regular acetylsalicylic acid medication (1.1% vs. 3.6%). In the multivariate analysis, however, neither acetylsalicylic acid use nor other type of pharmaceutical inhibition of COX-2 reduced the formation of de novo sIAs. The risk was mostly affected by age, smoking history and irregular usage of antihypertensive medication regardless of used COX-2 inhibition level. CONCLUSION: For the prevention of de novo sIA formation, risk factor management with focus on cessation of smoking and treating hypertension adequately seems more important than pharmaceutical COX-2 inhibition.

Use of antihypertensive medication and formation of de novo intracranial aneurysms.

BACKGROUND AND PURPOSE: Hypertension is a risk factor for subarachnoid hemorrhage and is also considered a risk factor for saccular intracranial aneurysm (sIA) formation. However, there is little direct evidence that antihypertensive medication will reduce sIA formation. METHODS: The impact of antihypertensive medication on de novo sIA formation was studied in an angiographically followed cohort of 1419 patients. Patients were identified from our population-based Kuopio Intracranial Aneurysm Database, and data on the purchases of antihypertensive medication were obtained from a national registry. Univariate and multivariate analyses were used to investigate the risk factors. RESULTS: Of the 966 sIA patients who were prescribed with antihypertensive medication, 841 patients used the medication regularly; 20 of them had de novo sIA. One hundred and twenty-five patients used the medication irregularly and 12 of them developed de novo sIAs. Four hundred and fifty-three patients did not use antihypertensive medication even though 27 of them had a diagnosis of hypertension, and 10 of them developed de novo sIAs. In the multivariate analysis antihypertensive medication did not significantly reduce de novo sIA formation (hazard ratio [HR] 1.60, 95% confidence interval [CI] 0.84-3.06). Age at primary diagnosis (HR: 0.95, 95%: CI 0.93-0.98) and smoking history (HR: 5.53, 95% CI: 2.77-11.05) were significant risk factors for de novo sIA formation. Also, irregular usage of antihypertensive medication was a significant risk factor (HR: 3.84, 95% CI: 1.59-9.29) for de novo sIA formation. CONCLUSIONS: Antihypertensive agents were not associated with a reduction of de novo sIA formation, but irregular use of antihypertensive agents was associated with an increased risk of de novo sIA formation.

A Case of De Novo Basilar Artery Aneurysm Associated with Proximal Stenosis Treated by Coil Embolization.

Objective: This report highlights a case of a de novo aneurysm assumed to be caused by hemodynamic stress resulting from proximal basilar artery stenosis. Case Presentation: A 76-year-old woman presented at our hospital with tinnitus. Although MRI did not reveal the cause of her tinnitus, it did uncover an incidental finding of basilar artery stenosis. The patient reported a history of cerebral infarction, diabetes, and hypertension. Six years following the initial discovery of basilar artery stenosis, a saccular aneurysm was detected at the bifurcation of the basilar artery and the right anterior inferior cerebellar artery, corresponding to the distal portion of the basilar artery stenosis. Upon revelation of an enlarged aneurysm on the subsequent two-year follow-up MRI, the patient received coil embolization treatment. No signs of recurrence were observed on the next two-year follow-up MRI. Conclusion: It was assumed that proximal basilar artery arteriosclerotic stenosis had caused hemodynamic stress on the distal vessel wall, and that this was responsible for the formation and growth of a de novo aneurysm. This case suggests that cerebrovascular arteriosclerotic changes may be associated with de novo aneurysm formation and therefore requires careful follow-up.

Computational fluid dynamic analysis of the initiation of cerebral aneurysms.

OBJECTIVE: Relationships between aneurysm initiation and hemodynamic factors remain unclear since de novo aneurysms are rarely observed. Most previous computational fluid dynamics (CFD) studies have used artificially reproduced vessel geometries before aneurysm initiation for analysis. In this study, the authors investigated the hemodynamic factors related to aneurysm initiation by using angiographic images in patients with cerebral aneurysms taken before and after an aneurysm formation. METHODS: The authors identified 10 cases of de novo aneurysms in patients who underwent follow-up examinations for existing cerebral aneurysms located at a different vessel. The authors then reconstructed the vessel geometry from the images that were taken before aneurysm initiation. In addition, 34 arterial locations without aneurysms were selected as control cases. Hemodynamic parameters acting on the arterial walls were calculated by CFD analysis. RESULTS: In all de novo cases, the aneurysmal initiation area corresponded to the highest wall shear stress divergence (WSSD point), which indicated that there was a strong tensile force on the arterial wall at the initiation area. The other previously reported parameters did not show such correlations. Additionally, the pressure loss coefficient (PLc) was statistically significantly higher in the de novo cases (p < 0.01). The blood flow impact on the bifurcation apex, or the secondary flow accompanied by vortices, resulted in high tensile forces and high total pressure loss acting on the vessel wall. CONCLUSIONS: Aneurysm initiation may be more likely in an area where both tensile forces acting on the vessel wall and total pressure loss are large.

Case Report: De novo Vertebral Artery Dissection After Intravascular Stenting of the Contralateral Unruptured Vertebral Artery Aneurysm.

Spontaneous vertebral artery dissecting aneurysm has been increasingly attributed as a major cause of focal neurological deficits due to vertebrobasilar artery ischemia or subarachnoid hemorrhage (SAH). Although the development of spontaneous vertebral artery dissecting aneurysm (VADA) is rare, de novo VADA after treatment of contralateral vertebral artery (VA) is more less frequently observed. There are only a few reports related to de novo VADA after treatment of the contralateral VA in the medical literature. The mechanisms responsible for de novo dissection after treatment of unilateral VADA are still not clearly understood. In this manuscript, we report an unusual case of a patient with a de novo VADA after placement of a pipeline embolization device (PED) stent on the contralateral VA along with a thorough review of the literature. A 42-years old male patient was referred to the hospital with sudden onset of dizziness, nausea, and vomiting. Initial digital subtraction angiography (DSA) images demonstrated a VADA in the fourth segment of the left VA without the involvement of the posterior inferior cerebellar artery (PICA). There were no significant abnormalities found in the right vertebral artery. He underwent an endovascular pipeline embolization to treat the dissecting aneurysm (DA). Surprisingly, follow-up DSA imaging 14 months after the initial treatment showed a segmental dilatation and narrowing of the right VA, which suggested a de novo VADA on the right side that had occurred postoperatively. This was followed by a tent-assisted coil embolization therapy for occluding this de novo VADA. This patient showed an uneventful postoperative course with no neurological abnormalities. In addition to hemodynamic stress changes, the unique clinicopathological features of dissecting aneurysms may contribute significantly to the pathogenesis of de novo VA dissection. Given that VA in VADA patients may be vulnerable on both sides, it is important to consider the risk of de novo dissection after initial aneurysm treatment. The bilateral vertebral artery has to be carefully observed when treating any VADA patient to prevent any complications.

Assessment of risk factors in de novo aneurysm development.

Aneurysms that occur anywhere in intracranial except where primary aneurysms develop, are called "de novo aneurysms". The risk factors and formation time of de novo aneurysms are not fully known. Congenital, environmental and hemodynamic factors can play a role in aneurysm development. The 43-year-old female patient was operated with the middle cerebral artery superior trunk aneurysm in our clinic. She came to us again after 17 months with a severe headache. In computed cranial tomography angiography, the middle cerebral artery superior trunk placement aneurysm was found to have a partial clip and "de novo aneurysm" was developed. She was re-operated for "de novo aneurysm". In this study, the risk factors in development of "de novo aneurysms" were discussed in the light of literature through this patient.

Malignant clinical course of mycotic intracranial aneurysms in children: A review.

BACKGROUND: Mycotic aneurysms are a rare in the pediatric population. The natural history of these lesions and their appropriate management strategies is controversial. CASE DESCRIPTION: A 13-year-old male presented with the sudden onset of a headache, vomiting, and fever. Inflammatory markers were elevated, and the blood culture was positive for Streptococcus viridans. When the computed tomography angiography (CTA) showed a ruptured mycotic aneurysm accompanied by multiple small unruptured aneurysms, he was started on antibiotics and underwent an urgent craniotomy. Despite negative blood cultures, the follow-up CTA showed further enlargement of the previously diagnosed aneurysms and a new right frontal aneurysm. The second and third craniotomies were, respectively, performed to resect the additional aneurysms. Pathologically, both aneurysmal walls were markedly inflamed and attenuated, suggesting the imminent risk of aneurysmal rupture. Following the total of three craniotomies, the patient had an uneventful postoperative course. Within 2 weeks, he regained baseline neurological function. CONCLUSION: Mycotic aneurysms in children may follow a very malignant course. Aneurysms may grow, new ones may form, and repeated CTAs are required to direct further follow-up treatment.

Rapid de novo Formation of a Large Aneurysm in a Patient with Fibromuscular Dysplasia.

Objective: The authors report the first case of intracranial fibromuscular dysplasia (FMD) presenting with rapid de novo formation of an unruptured large vertebral artery (VA) fusiform aneurysm. Case Presentation: A 41-year-old man presented with left hemiparesis. He had a giant thrombosed aneurysm at the basilar artery-superior cerebellar artery (BA-SCA) junction and a left extracranial VA aneurysm. A de novo VA fusiform aneurysm developed during a 1-month interval following the first session of intravascular coil embolization for the BA-SCA aneurysm. Stress on the fragile artery due to FMD during micro-catheterization may have caused the de novo aneurysm. An anomalous aortic origin of the left VA may also have played a role in the formation of the large de novo aneurysm and extracranial VA aneurysm. We performed overlapping stent-assisted coil embolization for the VA fusiform aneurysm using an Enterprise VRDs, and coil embolization for the BA-SCA thrombosed aneurysm using the stent-assisted technique with an Enterprise stent. Both aneurysms remained occluded for 7 years. Conclusion: We concluded micro-catheterization to be the cause of the large de novo aneurysm. This case emphasizes the importance of carefully performing intravascular interventional procedures for patients with FMD.

Refractory De Novo Multiple Cerebral Aneurysms After Radiotherapy and Multistaged "Open" Surgical Treatment for Low-Grade Glioma During Long-Term Follow-Up: A Case Report and Review of the Literature.

BACKGROUND: Radiation-induced aneurysms have been previously reported; however, multiple and repeated de novo aneurysm formation chronologically and anatomically during long-term follow-up have not yet been observed. The pathogenesis of persistent radiation-induced vasculopathy is not fully understood. CASE DESCRIPTION: A 31-year-old woman presented with intraventricular hemorrhage due to rupture of a right internal carotid artery (ICA) aneurysm that developed 17 years after surgical resection of a low-grade glioma in the right frontal lobe and postoperative radiotherapy (focal, 50 Gy/25 fractions). During glioma follow-up, salvage surgery with adjuvant gamma knife therapy and chemotherapy (ranimustine, vincristine, temozolomide) were performed for recurrence of the glioma. The aneurysm was treated with endovascular coil embolization. However, she experienced repeated intraventricular hemorrhages, and angiography revealed a de novo ICA aneurysm. The de novo aneurysms were treated with endovascular surgery using coil embolization and stenting. At 2 years after the third hemorrhage, the surgical wound became dehiscent, probably due to wound infection, thus epicranial soft tissue reconstruction using vascularized skin flap was performed. Despite multistaged endovascular surgery for the ICA aneurysm, she experienced repeated subarachnoid and intraventricular hemorrhages. Angiography revealed a de novo aneurysm of the right posterior cerebral artery and basilar trunk. She underwent coil embolization and stenting. Despite active management with endovascular surgery and close follow-up, she died after an eighth consecutive intraventricular and intracerebral hemorrhage caused by a de novo large aneurysm of the posterior cerebral artery. CONCLUSIONS: To the best of our knowledge, the present study is the first to report on of refractory and recurring de novo aneurysms treated by multistaged endovascular surgery during a long-term follow-up after radiotherapy and multistaged craniotomy for glioma.

De Novo Aneurysm Formation After Wingspan Stenting of Intracranial Carotid Stenosis: Computational Hemodynamic Analysis.

BACKGROUND: The pathophysiology of de novo aneurysm after stenting is poorly understood. Hemodynamic effects may play an important role. We report and discuss the hemodynamic analysis of de novo aneurysm after intracranial stenting. CASE DESCRIPTION: A 51-year-old female underwent angioplasty and coiling for stenosis associated with an aneurysm of the left intracranial carotid artery. Six years later, the follow-up digital subtraction angiography demonstrated a de novo aneurysm at the proximal tine of the Wingspan stent. Computational fluid dynamics simulations showed that stenting for intracranial stenosis resulted in higher oscillatory shear index and lower time-averaged wall shear stress in the neck region of de novo aneurysm. CONCLUSIONS: The hemodynamic change after stenting may lead to formation of a de novo aneurysm. After an initial injury that might result from the tine on the endothelial cells, stenting could produce high oscillatory shear index and low time-averaged wall shear stress near the tine, thus potentially inducing de novo aneurysm formation.

Natural History of De Novo Aneurysm Formation in Patients with Treated Aneurysmatic Subarachnoid Hemorrhage: A Ten-Year Follow-Up.

BACKGROUND: De novo aneurysm formation after completely occluded aneurysms via clipping or coiling has not been well studied. Although known to occur several years after initial aneurysm management, the natural history of de novo aneurysms is obscure. We investigated the formation of new aneurysms in patients who had previously undergone treatment of intracranial aneurysms. METHODS: In a retrospective, single-institutional series, eligible patients who had undergone treatment of ruptured cerebral aneurysms from 2000 to 2011 were included. The primary outcome measure was the development of de novo aneurysms during long-term follow-up. RESULTS: Overall, 130 patients (63% women) who had undergone microsurgical clipping (n = 63; 48.5%) or endovascular coiling (n = 67%; 51.5%) for ruptured aneurysms were included. The average follow-up time for our cohort was 10 ± 2.7 years. De novo aneurysms occurred in 10 of 130 patients (7.7%), with a mean time of 7.9 years for aneurysm detection. No association between the formation of de novo aneurysms and the location of the treated aneurysms, smoking status, hypertension, age, or gender was found. Follow-up imaging studies were performed every 2 years. De novo aneurysms had formed in 2 patients within 2-5 years, 7 patients after 5-10 years, and 1 patient after 10 years of follow-up. In 2 of 10 patients, the de novo aneurysm had ruptured and led to subarachnoid haemorrhage. CONCLUSION: The rate of de novo aneurysm occurrence was 7.6%, with a mean time to development of 7.9 years. This underscores the significance of long-term monitoring of patients with intracranial aneurysms. In our series, most new aneurysms had occurred after 5 years of follow-up.

Risk of de novo aneurysm formation in patients with a prior diagnosis of ruptured or unruptured aneurysm: systematic review and meta-analysis.

OBJECTIVE: De novo aneurysms are rare entities periodically discovered during follow-up imaging. Little is known regarding the frequency with which these lesions form or the time course. This systematic review and meta-analysis was undertaken to estimate the incidence of de novo aneurysms and to determine risk factors for aneurysm formation. METHODS: The authors searched multiple databases for studies of patients with unruptured and ruptured aneurysms describing the rate of de novo aneurysm formation. The primary outcome was incidence of de novo aneurysm formation. A meta-analysis was performed using a random-effects model. The authors examined the associations of multiple aneurysms, prior subarachnoid hemorrhage, smoking, sex, age at presentation, and hypertension with de novo aneurysm formation. RESULTS: The meta-analysis included 14,968 aneurysm patients who received imaging follow-up from 35 studies. The overall incidence of de novo aneurysm formation was 2% (95% CI 2%-3%) over a mean follow-up time of 8.3 years. The estimated incidence density was 0.3%/patient-year. There was no statistically significant difference in rates of de novo aneurysm formation between patients who had ruptured aneurysms and those with unruptured aneurysms. In 8 studies, 11.2% of de novo aneurysms were found in patients with ≤ 5 years of follow-up and 88.8% were found at > 5 years. The mean time to rupture for de novo aneurysms was 10 years. CONCLUSIONS: This systematic review demonstrates that formation of de novo aneurysms is rare. Overall, routine screening for de novo aneurysms is likely to be of low yield and could be performed at time intervals of at least 5 to 10 years.

De novo aneurysm formation of a feeder artery after embolization of a dural arteriovenous fistula and rupture during second embolization.

Objective Hemorrhage during embolization of dural arteriovenous fistula (DAVF) is a rare but devastating complication. This study was undertaken to analyze the causes of hemorrhage and avoid complication. Methods The clinical data of a case of DAVF with hemorrhagic complication were retrospectively collected and analyzed. Results The patient in this case presented with DAVF and two de novo aneurysms of a feeder artery after the first embolization. One de novo aneurysm ruptured during the second embolization of the DAVF because of hemodynamic change. Computed tomography showed a subdural hematoma, and surgical exploration was emergently performed. However, the patient died at postoperative day 10. Conclusions De novo aneurysm of a feeder artery may form after embolization of DAVF because of hemodynamic change. It has a high risk of rupture and should be a primary consideration in embolization of DAVF.

Lethal Ultra-Early Subarachnoid Hemorrhage Due to Rupture of De Novo Aneurysm 5 Months After Primary Aneurysmatic Subarachnoid Hemorrhage.

BACKGROUND: Approximately 1% of all patients surviving rupture of a cerebral aneurysm suffer from a second aneurysmatic subarachnoid hemorrhage later in their lives, 61% of which are caused by rupture of a de novo aneurysm. Latency between bleedings is usually many years, and younger patients tend to achieve better outcomes from a second subarachnoid hemorrhage. CASE DESCRIPTION: We report an unusual case of lethal ultra-early rupture of a de novo aneurysm of the anterior communicating artery only 5 months after the initial subarachnoid hemorrhage and complete coiling in a young, healthy male patient. CONCLUSION: Despite complete aneurysm obliteration, young age, and good recovery, patients may be subjected to secondary subarachnoid hemorrhages from de novo aneurysms after only a few months of the initial bleeding. Early-control magnetic resonance angiography might hence be advisable.

De novo giant posterior cerebral artery aneurysm developing 25 years after basilar bifurcation aneurysm treatment using a Drake tourniquet: case report and implications for aneurysm follow-up.

The objective of this paper was to report a rare complication of basilar artery (BA) tourniquet treatment of a giant basilar tip aneurysm, and to discuss possible causes for the formation of a de novo giant posterior cerebral artery (PCA) aneurysm. A 34-year-old woman underwent satisfactory treatment of a ruptured giant basilar bifurcation aneurysm by BA ligation (Drake tourniquet) in 1985. She presented 25 years later with a new aneurysm in the left PCA, successfully treated by coil embolization. To the authors' knowledge, this is the first case of de novo aneurysm formation on a PCA, and the first de novo aneurysm reported as a complication of BA ligation therapy by Drake tourniquet. Long-term follow-up is necessary in patients with treated cerebral aneurysms, particularly those occurring in young patients, those with multiple aneurysms, those with complex posterior circulation aneurysms, and those undergoing flow diversion or flow-altering therapies.

Treatment of Brain Arteriovenous Malformations with Hemodynamic Aneurysms: A Series of 131 Consecutive Cases.

BACKGROUND: The natural history of hemodynamic aneurysms (HAs) associated with brain arteriovenous malformations (AVMs) remains controversial, with no single approach to treatment. The purpose of this study was to justify preventive treatment tactics for HAs that pose an increased risk of rupture based on hemodynamic studies demonstrating hypertension in the afferent bed after AVM exclusion. METHODS: This retrospective analysis included 131 of 1740 patients (8%) with brain AVMs and at least 1 aneurysm treated at Burdenko Neurosurgical Institute between 2000 and 2016. Treatment consisted of microsurgery, endovascular interventions, or a combination of modalities. Patients were evaluated with the modified Rankin Scale before and after treatment. RESULTS: A total of 205 aneurysms were discovered. Multiple HAs were found in 46 patients (35%), and were significantly more often associated with posterior fossa AVMs; in addition, most were distally located. There was no difference in the incidence of hemorrhage between proximal and distal HAs. Microsurgical treatment was marked by high radicalism; 85% of HAs and 94% of AVMs were totally excluded based on control studies. In 10 cases, aneurysms were found after AVM removal, including 4 de novo aneurysms. In 1 case, the aneurysm regressed after AVM treatment. The mortality rate was 2.3%. CONCLUSIONS: Preoperative imaging should be carefully examined for associated aneurysms before and after surgical treatment. Our data suggests that HA exclusion, either as the first step or simultaneously with AVM treatment, is most beneficial to patients.