A comprehensive analysis of patients with cerebral arteriovenous malformation with headache: assessment of risk factors and treatment effectiveness

BACKGROUND

Due to the high mortality and disability rate of intracranial hemorrhage, headache is not the main focus of research on cerebral arteriovenous malformation (AVM), so research on headaches in AVM is still scarce, and the clinical understanding is shallow. This study aims to delineate the risk factors associated with headaches in AVM and to compare the effectiveness of various intervention treatments versus conservative treatment in alleviating headache symptoms.

METHODS

This study conducted a retrospective analysis of AVMs who were treated in our institution from August 2011 to December 2021. Multivariable logistic regression analysis was employed to assess the risk factors for headaches in AVMs with unruptured, non-epileptic. Additionally, the effectiveness of different intervention treatments compared to conservative management in alleviating headaches was evaluated through propensity score matching (PSM).

RESULTS

A total of 946 patients were included in the analysis of risk factors for headaches. Multivariate logistic regression analysis identified that female (OR 1.532, 95% CI 1.173-2.001, p = 0.002), supply artery dilatation (OR 1.423, 95% CI 1.082-1.872, p = 0.012), and occipital lobe (OR 1.785, 95% CI 1.307-2.439, p < 0.001) as independent risk factors for the occurrence of headaches. There were 443 AVMs with headache symptoms. After propensity score matching, the microsurgery group (OR 7.27, 95% CI 2.82-18.7 p < 0.001), stereotactic radiosurgery group(OR 9.46, 95% CI 2.26-39.6, p = 0.002), and multimodality treatment group (OR 8.34 95% CI 2.87-24.3, p < 0.001) demonstrate significant headache relief compared to the conservative group. However, there was no significant difference between the embolization group (OR 2.24 95% CI 0.88-5.69, p = 0.091) and the conservative group.

CONCLUSIONS

This study identified potential risk factors for headaches in AVMs and found that microsurgery, stereotactic radiosurgery, and multimodal therapy had significant benefits in headache relief compared to conservative treatment. These findings provide important guidance for clinicians when developing treatment options that can help improve overall treatment outcomes and quality of life for patients.

Minor micro-rheological alterations in the presence of an artificial saphenous arteriovenous shunt, as an arteriovenous malformation model in the rat

BACKGROUND

Arteriovenous malformations (AVMs) are vascular anomalies characterized by abnormal shunting between arteries and veins. The progression of the AVMs and their hemodynamic and rheological relations are poorly studied, and there is a lack of a feasible experimental model.

OBJECTIVE

To establish a model that cause only minimal micro-rheological alterations, compared to other AV models.

METHODS

Sixteen female Sprague Dawley rats were randomly divided into control and AVM groups. End-to-end anastomoses were created between the saphenous veins and arteries to mimic AVM nidus. Hematological and hemorheological parameters were analyzed before surgery and on the 1st, 3rd, 5th, 7th, 9th, and 12th postoperative weeks.

RESULTS

Compared to sham-operated Control group the AVM group did not show important alterations in hematological parameters nor in erythrocyte aggregation and deformability. However, slightly increased aggregation and moderately decreased deformability values were found, without significant differences. The changes normalized by the 12th postoperative week.

CONCLUSIONS

The presented rat model of a small-caliber AVM created on saphenous vessels does not cause significant micro-rheological changes. The alterations found were most likely related to the acute phase reactions and not to the presence of a small-caliber shunt. The model seems to be suitable for further studies of AVM progression.

Temporal lobe tumors modify local venous drainage

OBJECTIVE

Superficial Middle Cerebral Vein (SMCV) is an anastomotic vein frequently exposed during surgery. Changes in the pattern of cerebral venous outflow can occur in many pathological settings. We explored the hypothesis that the growth of an intracranial tumor could determine alterations in the venous outflow. We analyzed SMCV anatomical variants in patients undergoing surgery for intracranial tumors; we furthermore focused on association with histology.

METHODS

We retrospectively collected data of 120 patients undergoing surgery, 60 presenting intracranial tumor and 60 presenting cerebral aneurysms (control group). Tumor series was divided into "Low Growth-Rate tumors" (WHO grade I and II) and "High Growth-Rate tumors" (WHO grade III and IV). Anatomical variants of SMCV were analyzed on intraoperative videos and then classified as Type 1 (normotrophic), 2 A (hypotrophic) and Type 2B (absent/atrophic). We furthermore defined as Type 2 any alteration of the SMCV (2 A+2B) encountered. Relationships among SMCV types and both populations were analyzed using the chi-squared test; values of p < 0.05 were considered statistically significant.

RESULTS

We found a positive correlation between the presence of a primary brain tumor and Type 2B SMCV (PC.004, p < 0.05) and Type 2 SMCV (PC.000, p < 0.05). Specifically, we found a strong correlation between the absence of SMCV (Type 2B) and both tumors subgroups. Thus, the growth of a primary brain tumor seems to affect the cerebral local outflow.

CONCLUSIONS

Primary brain tumors seem to alter local venous network of SMCV. Clinical and oncological implications remain subject of further investigation.

Rheological Properties of Non-Adhesive Embolizing Compounds-The Key to Fine-Tuning Embolization Process-Modeling in Endovascular Surgery

The study of polymers' rheological properties is of paramount importance both for the problems of their industrial production as well as for their practical application. Two polymers used for embolization of arteriovenous malformations (AVMs) are studied in this work: Onyx-18^® and Squid-12^®. Viscosity curve tests and computational fluid dynamics (CFD) were used to uncover viscosity law as a function of shear rate as well as behavior of the polymers in catheter or pathological tissue models. The property of thermal activation of viscosity was demonstrated, namely, the law of dependence of viscosity on temperature in the range from 20 °C to 37 °C was established. A zone of viscosity nonmonotonicity was identified, and a physical interpretation of the dependence of the embolic polymers' viscosity on the shear rate was given on the basis of Cisco's model. The obtained empirical constants will be useful for researchers based on the CFD of AVMs. A description of the process of temperature activation of the embolic polymers' viscosity is important for understanding the mechanics of the embolization process by practicing surgeons as well as for producing new prospective embolic agents.

Angioarchitectural features of brain arteriovenous malformation presented with seizures

Seizures are the second most common manifestations of brain arteriovenous malformations (bAVMs). This study was conducted to investigate the clinical and angioarchitectural features of bAVMs with seizures and provide guidelines for the clinical management of these patients. We collected clinical and radiological data on patients with bAVMs diagnosed by digital subtraction angiography between January 2013 and December 2020 and dichotomized the patients into the seizures and non-seizures groups. We identified differences in demographic and angiographic features. Logistic regression and random forest (RF) models were developed and compared. The diagnostic capacity was assessed using receiver operating characteristic (ROC) curves. A nomogram was constructed, and the clinical impact was determined by decision curve analysis. A total of 414 patients with bAVMs were included in the analysis, of which 78 (18.8%) had bAVM-related seizures. In the multivariable logistic regression model, the location and side of bAVMs were independently associated with seizures. In RF models, the maximal diameter of veins and the cross-sectional area of feeding arteries and draining veins were the most important features. ROC curves showed that the RF model was not better than MLR in predicting seizures. Decision curve analysis revealed that the use of a constructed nomogram to stratify the seizure patients was beneficial at all threshold probabilities in our study. The side and location of bAVMs are specific angioarchitectural features independently associated with the occurrences of seizures with bAVMs.

Optimal control problem arising in mathematical modeling of cerebral vascular pathology embolization

Arteriovenous malformation (AVM) of the brain is a congenital vascular abnormality, in which the arterial and venous blood pools are intertwined and directly connected. This dangerous disease causes a high risk of intracranial hemorrhage and disrupts brain functioning. The preferred method of AVM treating is embolization, which is the endovascular filling of abnormal AVM vessels with a special embolic agent. Despite the fact that this method is widely used in neurosurgery, in some cases its use is accompanied by perioperative AVM vessels rupture. In this regard, the aim of this work is to study the optimal scenarios for multi-stage AVM embolization from the effectiveness and safety of the procedure point of view. Mathematically, the joint movement of blood and embolic agent in the AVM body is described on the basis of a one-dimensional two-phase filtration model, which takes into account the redistribution of blood to surrounding healthy vessels. For the numerical solution of the resulting integro-differential system of equations, a monotonic modification of the CABARET scheme is used. To find optimal embolization scenarios, the optimal control problem with phase constraints arising from medicine is formulated. A modified particle swarm optimization method is used to solve this problem numerically. This technique is used to obtain optimal embolization scenarios on the basis of real patients clinical data collected during neurosurgical operations.

Complete seizure-free rates following interventional treatment of intracranial arteriovenous malformations: a systematic review and meta-analysis

Seizures are common presenting symptoms of intracranial arteriovenous malformations (AVMs). This systematic review and meta-analysis aims to assess the current evidence regarding complete seizure freedom rates following surgical resection, stereotactic radiosurgery (SRS), and/or endovascular embolization of intracranial AVMs. A systematic review of PubMed, Ovid MEDLINE, and Ovid EMBASE was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Included manuscripts were methodically scrutinized for quality, spontaneous AVM-associated or hemorrhage-associated seizures, complete seizure-free rates following each interventional treatment, follow-up duration; determination methods of seizure outcomes, and average time-to-onset of recurrent seizures after each treatment. Manuscripts that described patients with nondisabling seizures or reduced seizure frequency in their seizure-free calculations were excluded. Seizure freedom rates following surgical resection, SRS, and endovascular embolization were compared via random-effect analysis. Thirty-four studies with a total of 1765 intracranial AVM patients presenting with spontaneous AVM-associated seizures and 408 patients presenting with hemorrhage-associated seizures were qualitatively analyzed. For patients presenting with AVM-associated seizures, the complete seizure-free rates were 73.0% (321/440 patients; 95% CI 68.8-77.1%) following surgical resection, 60.5% (376/622 patients; 95% CI 56.6-64.3%) following SRS, and 44.6% (29/65 patients; 95% CI 32.5-56.7%) following endovascular embolization alone. For patients presenting with either AVM-associated or hemorrhage-associated seizures, the complete seizure-free rates were 73.0% (584/800 patients; 95% CI 69.9-76.1%) following surgical resection, 46.4% (572/1233 patients; 95% CI 43.6-49.2%) following SRS, and 44.6% (29/65 patients; 95% CI 32.5-56.7%) following embolization. For patients presenting with either AVM-associated or hemorrhage-associated seizures, the overall improvements in seizure outcomes regardless of complete seizure freedom were 82.6% (661/800 patients; 95% CI 80.0-85.3%), 70.6% (870/1233 patients; 95% CI 68.0-73.1%), and 70.8% (46/65 patients; 95% CI 59.7-81.1%) following surgical resection, SRS, and embolization, respectively. No study reported information about the time-to-onset for recurrent seizures in any patient following treatment, as seizure outcomes were only described at the last follow-up visit. The available data suggests that surgical resection results in the highest rate of complete seizure freedom. The rate of seizure improvement following surgery increased further to 82.3% when including patients who had improved seizure frequency without achieving true seizure freedom. Complete seizure-free rates following SRS or embolization were more ambiguous and lower when compared to surgical resection. There is a need for high quality studies evaluating AVM treatment modalities and clearly defined seizure outcomes, as the current literature consists mostly of heterogenous patient populations.

Hemodynamic Analysis of Cerebral AVMs with 3D Phase-Contrast MR Imaging

BACKGROUND AND PURPOSE

The hemodynamics associated with cerebral AVMs have a significant impact on their clinical presentation. This study aimed to evaluate the hemodynamic features of AVMs using 3D phase-contrast MR imaging with dual velocity-encodings.

MATERIALS AND METHODS

Thirty-two patients with supratentorial AVMs who had not received any previous treatment and had undergone 3D phase-contrast MR imaging were included in this study. The nidus diameter and volume were measured for classification of AVMs (small, medium, or large). Flow parameters measured included apparent AVM inflow, AVM inflow index, apparent AVM outflow, AVM outflow index, and the apparent AVM inflow-to-outflow ratio. Correlation coefficients between the nidus volume and each flow were calculated. The flow parameters between small and other AVMs as well as between nonhemorrhagic and hemorrhagic AVMs were compared.

RESULTS

Patients were divided into hemorrhagic (n = 8) and nonhemorrhagic (n = 24) groups. The correlation coefficient between the nidus volume and the apparent AVM inflow and outflow was .83. The apparent AVM inflow and outflow in small AVMs were significantly smaller than in medium AVMs (P < .001 for both groups). The apparent AVM inflow-to-outflow ratio was significantly larger in the hemorrhagic AVMs than in the nonhemorrhagic AVMs (P = .02).

CONCLUSIONS

The apparent AVM inflow-to-outflow ratio was the only significant parameter that differed between nonhemorrhagic and hemorrhagic AVMs, suggesting that a poor drainage system may increase AVM pressure, potentially causing cerebral hemorrhage.

Erratum to Evaluating the safety and efficacy of various endovascular approaches for the treatment of infectious intracranial aneurysms: a systematic review. World Neurosurgery. Volume 144, December 2020, Pages 293-298.e15

OBJECTIVE

A review of endovascular cerebral mycotic aneurysm treatment with Onyx liquid embolic, N-butyl-2-cyanoacrylate (NBCA), or coil embolization has not been reported. The authors conduct a systematic review on endovascular treatment methods of mycotic aneurysms.

METHODS

A systematic literature review was performed using the PubMed and MEDLINE databases for studies published between 1986 and 2020. All studies assessing outcomes related to endovascular Onyx embolization, NBCA embolization, or coiling were included.

RESULTS

A total of 74 studies were ultimately selected, including 180 (67% male) patients comprising 243 aneurysms treated endovascularly. The mean age was 38.2 ± 17.6 years, and the most common symptom on presentation was headache (31%). Most aneurysms were located on the middle cerebral artery (52.5%), and over half presented with rupture (53.8%). Coiling was the most commonly employed technique (50.4%), and obliteration rates were comparable across coiling, NBCA, and Onyx (99.1%, 100%, 100%, respectively). Complication rates were also comparable (4.3% vs. 15.2% vs. 8.1%).

CONCLUSION

Embolization for infectious intracranial aneurysm appears to be an effective treatment option for mycotic aneurysms. Embolization rates were comparable between coiling, NBCA, and Onyx embolization. Noninferiority among these modalities cannot be demonstrated given the retrospective nature of this review, evolution of endovascular techniques over the years, and changes in treatment paradigms in the last 2 decades. Ideally, further prospective research will be needed to find which treatment method offers the lowest complication rates and the best outcomes for patients with mycotic aneurysms.

Evaluating the Safety and Efficacy of Various Endovascular Approaches for Treatment of Infectious Intracranial Aneurysms: A Systematic Review

OBJECTIVE

A review of endovascular cerebral mycotic aneurysm treatment with Onyx liquid embolic, N-butyl-2-cyanoacrylate (NBCA), or coil embolization has not been reported. The authors conduct a systematic review on endovascular treatment methods of mycotic aneurysms.

METHODS

A systematic literature review was performed using the PubMed and MEDLINE databases for studies published between 1986 and 2020. All studies assessing outcomes related to endovascular Onyx embolization, NBCA embolization, or coiling were included.

RESULTS

A total of 73 studies were ultimately selected including 180 (67% male) patients comprising 243 aneurysms treated endovascularly. The mean age was 38.2 ± 17.6 years, and the most common symptom on presentation was headache (31%). Most aneurysms were located on the middle cerebral artery (52.5%), and over half presented with rupture (53.8%). Coiling was the most commonly employed technique (50.4%), and obliteration rates were comparable across coiling, NBCA, and Onyx (99.1%, 100%, 100%, respectively). Complication rates were also comparable (4.3% vs. 15.2% vs. 8.1%).

CONCLUSIONS

Embolization for infectious intracranial aneurysm appears to be an effective treatment option for mycotic aneurysms. Embolization rates were comparable among coiling, NBCA, and Onyx embolization. Noninferiority among these modalities cannot be demonstrated given the retrospective nature of this review, evolution of endovascular techniques over the years, and changes in treatment paradigms in the past 2 decades. Ideally, further prospective research will be necessary to find which treatment method offers the lowest complication rates and the best outcomes for patients with mycotic aneurysms.

Endovascular and Surgical Treatment Is Predictive of Readmission Risk After Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

Aneurysmal subarachnoid hemorrhage (aSAH) is a debilitating disease process accounting for 5% of strokes. Although improvements in care have reduced the case-fatality rates, patients have an increased risk of neurological and medical complications after discharge. Additionally, the readmission rates have been increasingly used as a metric for patient care quality.

METHODS

In the present study, we reviewed the medical records of 206 patients who had been treated for aSAH at the University of Virginia from 2011 to 2018 to identify the causes and predictors of readmission.

RESULTS

The all-cause readmission rate was 9.8%, 15.3%, and 21.3% within 30, 60, and 180 days, respectively. The readmission rate for neurologic causes was 7.7%, 12.6%, and 18.0% within 30, 60, and 180 days, respectively. The neurologic causes of readmission included aneurysm retreatment, cranioplasty, a fall, hydrocephalus, stroke symptoms, and syncope. Surgical treatment (odds ratio [OR], 4.11-6.30) and endovascular treatment (OR, 3.79-8.33) of vasospasm were associated with an increased risk of all-cause readmission. Endovascular aneurysm treatment (OR, 0.22) was associated with a decreased risk of all-cause readmission. The average interval to the first follow-up appointment at our institution was 55.3 ± 63.3 days. Of the patients who had been readmitted from the emergency room, 65% had not had follow-up contact with physicians at our institution until their readmission.

CONCLUSIONS

To the best of our knowledge, the present study is the first to have examined the readmission rates for subarachnoid hemorrhage >90 days after treatment. Our results have suggested that the readmission rates >90 days after treatment could still be predicted by the hospital and treatment course during admission and that follow-up appointments with patients earlier in the clinic could identify those patients with a greater risk of readmission.

Modelling of the arteriovenous malformation embolization optimal scenario

Cerebral arteriovenous malformation (AVM) is a congenital brain vessels pathology, in which the arterial and venous blood channels are connected by tangles of abnormal blood vessels. It is a dangerous disease that affects brain functioning causing the high risk of intracerebral haemorrhage. One of AVM treatment methods is embolization-the endovascular filling of the AVM vessel bundle with a special embolic agent. This method is widely used, but still in some cases is accompanied by intraoperative AVM vessels rupture. In this paper, the optimal scenario of AVM embolization is studied from the safety and effectiveness of the procedure point of view. The co-movement of blood and embolic agent in the AVM body is modelled on the basis of a one-dimensional two-phase filtration model. Optimal control problem with phase constraints arising from medicine is formulated and numerically solved. In numerical analysis, the monotone modification of the CABARET scheme is used. Optimal embolization model is constructed on the basis of real patients' clinical data collected during neurosurgical operations. For the special case of embolic agent, input admissible and optimal embolization scenarios were calculated.

Arteriovenous malformation presenting with epilepsy: a multimodal approach to diagnosis and treatment

Arteriovenous malformation (AVM) presenting with epilepsy significantly impacts patient quality of life, and it should be considered very much a seizure disorder. Although hemorrhage prevention is the primary treatment aim of AVM surgery, seizure control should also be at the forefront of therapeutic management. Several hemodynamic and morphological characteristics of AVM have been identified to be associated with seizure presentation. This includes increased AVM flow, presence of long pial draining vein, venous outflow obstruction, and frontotemporal location, among other aspects. With the advent of high-throughput image processing and quantification methods, new radiographic attributes of AVM-related epilepsy have been identified. With respect to therapy, several treatment approaches are available, including conservative management or interventional modalities; this includes microsurgery, radiosurgery, and embolization or a combination thereof. Many studies, especially in the domain of microsurgery and radiosurgery, evaluate both techniques with respect to seizure outcomes. The advantage of microsurgery lies in superior AVM obliteration rates and swift seizure response. In addition, by incorporating electrophysiological monitoring during AVM resection, adjacent or even remote epileptogenic foci can be identified, leading to extended lesionectomy and improved seizure control. Radiosurgery, despite resulting in reduced AVM obliteration and prolonged time to seizure freedom, avoids the risks of surgery altogether and may provide seizure control through various antiepileptic mechanisms. Embolization continues to be used as an adjuvant for both microsurgery and radiosurgery. In this study, the authors review the latest imaging techniques in characterizing AVM-related epilepsy, in addition to reviewing each treatment modality.

Risk factors for hemorrhage of brain arteriovenous malformation

Patients with brain arteriovenous malformation (bAVM) are at risk of intracranial hemorrhage (ICH). Overall, bAVM accounts for 25% of hemorrhagic strokes in adults <50 years of age. The treatment of unruptured bAVMs has become controversial, because the natural history of these patients may be less morbid than invasive therapies. Available treatments include observation, surgical resection, endovascular embolization, stereotactic radiosurgery, or combination thereof. Knowing the risk factors for bAVM hemorrhage is crucial for selecting appropriate therapeutic strategies. In this review, we discussed several biological risk factors, which may contribute to bAVM hemorrhage.