The risk of hemorrhage after radiosurgery for arteriovenous malformations

1996 ◽  
Vol 84 (6) ◽  
pp. 912-919 ◽  
Author(s):  
William A. Friedman ◽  
David L. Blatt ◽  
Frank J. Bova ◽  
John M. Buatti ◽  
William M. Mendenhall ◽  
...  
Keyword(s):  
Arteriovenous Malformations ◽  
Significant Risk ◽  
Content Type ◽  
Time Period ◽  
Detailed Statistical Analysis ◽  
History Of ◽  
Hemorrhage Risk ◽  
Risk Of Hemorrhage ◽  
Parametric Survival ◽  
Arterial Aneurysms

✓ Two hundred and one patients with arteriovenous malformations (AVMs) treated radiosurgically between May 1988 and February 1995 are analyzed in this study. Twelve patients sustained a posttreatment hemorrhage during this period. Pretreatment factors associated with increased hemorrhage risk were identified in 11 of these patients and included arterial aneurysms, venous aneurysms, venous outflow obstruction, periventricular location, prior embolization, and prior surgical treatment. A detailed statistical analysis, using both Poisson regression and parametric survival regression techniques, was undertaken to determine whether radiosurgery had any effect on the risk of hemorrhage, when compared to the natural history of the disease, in those patients in whom a complete angiographic cure was not achieved. No evidence was found to support a statistically significant departure from the natural hemorrhage rate at any time period after radiosurgical treatment. Significant risk factors for hemorrhage appeared to correlate with increasing AVM volume.

Arterial aneurysms associated with cerebral arteriovenous malformations: classification, incidence, and risk of hemorrhage

1998 ◽  
Vol 89 (4) ◽  
pp. 539-546 ◽  
Author(s):  
Gary Redekop ◽  
Karel TerBrugge ◽  
Walter Montanera ◽  
Robert Willinsky
Keyword(s):  
Arteriovenous Malformations ◽  
Clinical Presentation ◽  
Cerebral Arteriovenous Malformations ◽  
Content Type ◽  
Risk Of Bleeding ◽  
Risk Rate ◽  
Risk Of Hemorrhage ◽  
Arterial Aneurysms ◽  
Fine Print

Object. The goal of this study was to develop a classification system for aneurysms associated with arteriovenous malformations (AVMs) based on their anatomical and pathophysiological relationships and to determine the incidence and bleeding rates for these aneurysms as well as the effects of AVM treatment on their natural history. Methods. Of 632 patients with AVMs, intranidal aneurysms were found in 35 (5.5%) and flow-related aneurysms in 71 (11.2%). Patients with intranidal aneurysms presented more frequently with hemorrhage (72% compared with 40%, p < 0.001) and had a 9.8% per year risk rate of bleeding during follow-up review. Twelve (17%) of the patients with flow-related aneurysms associated with an AVM presented with hemorrhage from an aneurysm, whereas 15 (21%) bled from their AVM. Seventeen patients underwent angiography after AVM treatment (mean 2.25 years). Of 23 proximal aneurysms, 18 (78.3%) were unchanged, four (17.4%) were smaller, and one (4.3%) had disappeared, whereas four (80%) of five distal aneurysms regressed completely and one was unchanged. Sixteen patients underwent angiography after partial AVM treatment (mean 3.8 years). In cases with less than a 50% reduction in the AVM, no aneurysms regressed, although two enlarged and bled. In cases with greater than a 50% reduction in the AVM, two of three distal aneurysms disappeared and five proximal aneurysms were unchanged. Conclusions. Arterial aneurysms associated with cerebral AVMs may be classified as intranidal, flow-related, or unrelated to the AVM nidus. Intranidal aneurysms have a high correlation with hemorrhagic clinical presentation and a risk of bleeding during the follow-up period that considerably exceeds that which would be expected in their absence. Patients with flow-related aneurysms in association with an AVM may present with hemorrhage from either lesion. Aneurysms that arise on distal feeding arteries near the nidus have a high probability of regressing with substantial or curative AVM therapy.

Deep arteriovenous malformations of the basal ganglia and thalamus: natural history

2003 ◽  
Vol 98 (4) ◽  
pp. 747-750 ◽  
Author(s):  
Ian G. Fleetwood ◽  
Mary L. Marcellus ◽  
Richard P. Levy ◽  
Michael P. Marks ◽  
Gary K. Steinberg
Keyword(s):  
Basal Ganglia ◽  
Natural History ◽  
Arteriovenous Malformations ◽  
Venous Drainage ◽  
Neurological Injury ◽  
Content Type ◽  
Hemorrhagic Event ◽  
History Of ◽  
Risk Of Hemorrhage ◽  
Fine Print

Object. Patients with arteriovenous malformations (AVMs) in a deep location and with deep venous drainage are thought to be at higher risk for hemorrhage than those with AVMs in other locations. Despite this, the natural history of AVMs of the basal ganglia and thalamus has not been well studied. Methods. The authors retrospectively evaluated a cohort of 96 patients with AVMs in the basal ganglia and thalamus with respect to the tendency of these lesions to hemorrhage between the time of detection and their eventual successful management. The 96 patients studied had a mean age of 22.7 years at diagnosis, and 51% were male. Intracranial hemorrhage (ICH) was the event leading to clinical detection in 69 patients (71.9%), and 85.5% of these patients were left with hemiparesis. After diagnosis, 25 patients bled a total of 49 times. The cumulative clinical follow up after detection but before surgical management was 500.2 patient-years. The risk of hemorrhage after detection of an AVM of the basal ganglia or thalamus was 9.8% per patient-year. Conclusions. The rate of ICH in patients with AVMs of the basal ganglia or thalamus (9.8%/year) is much higher than the rate in patients with AVMs in other locations (2–4%/year). The risk of incurring a neurological deficit with each hemorrhagic event is high. Treatment of these patients at specialized centers is recommended to prevent neurological injury from a spontaneous ICH.

Treatment of brain arteriovenous malformations by embolization and radiosurgery

1996 ◽  
Vol 85 (1) ◽  
pp. 19-28 ◽  
Author(s):  
Y. Pierre Gobin ◽  
Alexandre Laurent ◽  
Louis Merienne ◽  
Maurice Schlienger ◽  
Armand Aymard ◽  
...  
Keyword(s):  
Arteriovenous Malformations ◽  
Morbidity Rate ◽  
Total Occlusion ◽  
Content Type ◽  
Brain Arteriovenous Malformations ◽  
History Of ◽  
Grade Ii ◽  
Risk Of Hemorrhage ◽  
Grade Iii

✓ Embolization was used to reduce the size of brain arteriovenous malformations (AVMs) prior to radiosurgical treatment in 125 patients who were poor surgical candidates or had refused surgery. Of these patients, 81% had suffered hemorrhage, and 22.4% had undergone treatment at another institution. According to the Spetzler—Martin scale, the AVMs were Grade II in 9.6%, Grade III in 31.2%, Grade IV in 30.4%, and Grades V to VI in 28.8% of the cases. Most embolizations were performed using cyanoacrylate delivered by flow-guided microcatheters. Radiosurgery was performed using a linear accelerator in 62 patients treated by the authors, and 34 patients were treated at other institutions using various methods. Embolization produced total occlusion in 11.2% of AVMs and reduced 76% of AVMs enough to allow radiosurgery. Radiosurgery produced total occlusion in 65% of the partially embolized AVMs (79% when the residual nidus was < 2 cm in diameter). Embolizations resulted in a mortality rate of 1.6% and a morbidity rate of 12.8%. No complications were associated with radiosurgery. The hemorrhage rate for partially embolized AVMs was 3% per year. No patient with a completely occluded AVM experienced rehemorrhage. Angiographic follow-up review of AVMs embolized with cyanoacrylate demonstrated a 11.8% revascularization rate, occurring within 1 year. It is concluded that after partial embolization with cyanoacrylate, the risk of hemorrhage from the residual nidus is comparable to the natural history of AVMs and that the residual nidus can be irradiated with results almost as good as for a native AVM of the same size.

The natural history of unruptured intracranial arteriovenous malformations

1988 ◽  
Vol 68 (3) ◽  
pp. 352-357 ◽  
Author(s):  
Robert D. Brown ◽  
David O. Wiebers ◽  
Glenn Forbes ◽  
W. Michael O'Fallon ◽  
David G. Piepgras ◽  
...  
Keyword(s):  
Natural History ◽  
Arteriovenous Malformations ◽  
Aneurysm Rupture ◽  
Intracranial Arteriovenous Malformations ◽  
Content Type ◽  
Risk Of Death ◽  
History Of ◽  
Risk Of Hemorrhage

✓ The authors conducted a long-term follow-up study of 168 patients to define the natural history of clinically unruptured intracranial arteriovenous malformations (AVM's). Charts of patients seen at the Mayo Clinic between 1974 and 1985 were reviewed. Follow-up information was obtained on 166 patients until death, surgery, or other intervention, or for at least 4 years after diagnosis (mean follow-up time 8.2 years). All available cerebral arteriograms and computerized tomography scans of the head were reviewed. Intracranial hemorrhage occurred in 31 patients (18%), due to AVM rupture in 29 and secondary to AVM or aneurysm rupture in two. The mean risk of hemorrhage was 2.2% per year, and the observed annual rates of hemorrhage increased over time. The risk of death from rupture was 29%, and 23% of survivors had significant long-term morbidity. The size of the AVM and the presence of treated or untreated hypertension were of no value in predicting rupture.

Stereotaxic clipping of arterial aneurysms and arteriovenous malformations

1977 ◽  
Vol 46 (1) ◽  
pp. 12-23 ◽  
Author(s):  
Edward I. Kandel ◽  
Vyacheslav V. Peresedov
Keyword(s):  
Arteriovenous Malformations ◽  
Internal Carotid ◽  
Special Device ◽  
Content Type ◽  
Arterial Aneurysms ◽  
Direct Attack ◽  
Fine Print

✓ In carefully selected cases of arterial aneurysms and deep-seated arteriovenous malformations (AVM), when direct attack may be dangerous or impossible, the authors advocate stereotaxic clipping. A special device and technique for its application are described. The instrument is introduced through a trephine opening and clipping is monitored by angiography. Successful results have been obtained in 10 operations performed on eight patients, three of whom had arterial aneurysms (two internal carotid and one anterior cerebral-anterior communicating) and five with AVM's.

Long-term complications after gamma knife surgery for arteriovenous malformations

2005 ◽  
Vol 102 (Special_Supplement) ◽  
pp. 34-37 ◽  
Author(s):  
Masahiro Izawa ◽  
Motohiro Hayashi ◽  
Mikhail Chernov ◽  
Koutarou Nakaya ◽  
Taku Ochiai ◽  
...  
Keyword(s):  
Gamma Knife ◽  
Arteriovenous Malformations ◽  
Cyst Formation ◽  
Gamma Knife Surgery ◽  
Content Type ◽  
Delayed Hemorrhage ◽  
Complete Obliteration ◽  
Risk Of Hemorrhage ◽  
Fine Print

Object. The authors analyzed of the long-term complications that occur 2 or more years after gamma knife surgery (GKS) for intracranial arteriovenous malformations (AVMs). Methods. Patients with previously untreated intracranial AVMs that were managed by GKS and followed for at least 2 years after treatment were selected for analysis (237 cases). Complete AVM obliteration was attained in 130 cases (54.9%), and incomplete obliteration in 107 cases (45.1%). Long-term complications were observed in 22 patients (9.3%). These complications included hemorrhage (eight cases), delayed cyst formation (eight cases), increase of seizure frequency (four cases), and middle cerebral artery stenosis and increased white matter signal intensity on T2-weighted magnetic resonance imaging (one case of each). The long-term complications were associated with larger nidus volume (p < 0.001) and a lobar location of the AVM (p < 0.01). Delayed hemorrhage was associated only with incomplete obliteration of the nidus (p < 0.05). Partial obliteration conveyed no benefit. Delayed cyst formation was associated with a higher maximal GKS dose (p < 0.001), larger nidus volume (p < 0.001), complete nidus obliteration (p < 0.01), and a lobar location of the AVM (p < 0.05). Conclusions. Incomplete obliteration of the nidus is the most important factor associated with delayed hemorrhagic complications. Partial obliteration does not seem to reduce the risk of hemorrhage. Complete obliteration can be complicated by delayed cyst formation, especially if high maximal treatment doses have been administered.

Natural history of unruptured intracranial aneurysms: probability of and risk factors for aneurysm rupture

2000 ◽  
Vol 93 (3) ◽  
pp. 379-387 ◽  
Author(s):  
Seppo Juvela ◽  
Matti Porras ◽  
Kristiina Poussa
Keyword(s):  
Risk Factors ◽  
Smoking Status ◽  
Significant Risk ◽  
Significant Risk Factor ◽  
Aneurysm Rupture ◽  
Content Type ◽  
Unruptured Aneurysms ◽  
Unruptured Intracranial Aneurysms ◽  
History Of ◽  
Fine Print

Object. The authors conducted a study to investigate the long-term natural history of unruptured intracranial aneurysms and the predictive risk factors determining subsequent rupture in a patient population in which surgical selection of cases was not performed.Methods. One hundred forty-two patients with 181 unruptured aneurysms were followed from the 1950s until death or the occurrence of subarachnoid hemorrhage or until the years 1997 to 1998. The annual and cumulative incidence of aneurysm rupture as well as several potential risk factors predictive of rupture were studied using life-table analyses and Cox's proportional hazards regression models including time-dependent covariates.The median follow-up time was 19.7 years (range 0.8–38.9 years). During 2575 person-years of follow up, there were 33 first-time episodes of hemorrhage from previously unruptured aneurysms, for an average annual incidence of 1.3%. In 17 patients, hemorrhage led to death. The cumulative rate of bleeding was 10.5% at 10 years, 23% at 20 years, and 30.3% at 30 years after diagnosis. The diameter of the unruptured aneurysm (relative risk [RR] 1.11 per mm in diameter, 95% confidence interval [CI] 1–1.23, p = 0.05) and patient age at diagnosis inversely (RR 0.97 per year, 95% CI 0.93–1, p = 0.05) were significant independent predictors for a subsequent aneurysm rupture after adjustment for sex, hypertension, and aneurysm group. Active smoking status at the time of diagnosis was a significant risk factor for aneurysm rupture (RR 1.46, 95% CI 1.04–2.06, p = 0.033) after adjustment for size of the aneurysm, patient age, sex, presence of hypertension, and aneurysm group. Active smoking status as a time-dependent covariate was an even more significant risk factor for aneurysm rupture (adjusted RR 3.04, 95% CI 1.21–7.66, p = 0.02).Conclusions. Cigarette smoking, size of the unruptured intracranial aneurysm, and age, inversely, are important factors determining risk for subsequent aneurysm rupture. The authors conclude that such unruptured aneurysms should be surgically treated regardless of their size and of a patient's smoking status, especially in young and middle-aged adults, if this is technically possible and if the patient's concurrent diseases are not contraindications. Cessation of smoking may also be a good alternative to surgery in older patients with small-sized aneurysms.

scholarly journals Management of intracranial aneurysms associated with arteriovenous malformations

2014 ◽  
Vol 37 (3) ◽  
pp. E11 ◽  
Author(s):  
Bruno C. Flores ◽  
Daniel R. Klinger ◽  
Kim l. Rickert ◽  
Samuel l. Barnett ◽  
Babu G. Welch ◽  
...  
Keyword(s):  
Natural History ◽  
Arteriovenous Malformations ◽  
Intracranial Aneurysms ◽  
Case Series ◽  
Classification Systems ◽  
Vascular Lesions ◽  
Difficult Decision ◽  
Hemorrhagic Events ◽  
History Of ◽  
Hemorrhage Risk

Intracranial or brain arteriovenous malformations (BAVMs) are some of the most interesting and challenging lesions treated by the cerebrovascular neurosurgeon. It is generally believed that the combination of BAVMs and intracranial aneurysms (IAs) is associated with higher hemorrhage rates at presentation and higher rehemorrhage rates and thus with a more aggressive course and natural history. There is wide variation in the literature on the prevalence of BAVM-associated aneurysms (range 2.7%–58%), with 10%–20% being most often cited in the largest case series. The risk of intracranial hemorrhage in patients with unruptured BAVMs and coexisting IAs has been reported to be 7% annually, compared with 2%–4% annually for those with BAVM alone. Several different classification systems have been applied in an attempt to better understand the natural history of this combination of lesions and implications for treatment. Independent of the classification used, it is clear that a few subtypes of aneurysms have a direct hemodynamic correlation with the BAVM itself. This is exemplified by the fact that the presence of a distal flow-related or an intranidal aneurysm appears to be associated with an increased hemorrhage risk, when compared with an aneurysm located on a vessel with no direct supply to the BAVM nidus. Debate still exists regarding the etiology of the association between those two vascular lesions, the subsequent implications for patients’ risk of hemorrhagic stroke, and finally the determination of which patients warrant treatment and when. The ultimate goals of the treatment of a BAVM associated with an IA are to prevent hemorrhage, avoid stepwise neurological deterioration, and eliminate the mortality risk associated with recurrent hemorrhagic events. The treatment is only justifiable if the risks associated with an intervention are lower than or equivalent to the long-term risks of disability or mortality caused by the lesion itself. When faced with this difficult decision, a few questions need to be answered by the treating neu-rosurgeon: What is the mode of presentation? What is the symptomatic lesion? Which one of the lesions bled? What is the relationship between the BAVM and IA? Is it possible to safely treat both BAVM and IA? The objective of this review is to discuss the demographics, natural history, classification, and strategies for management of BAVMs associated with IAs.

scholarly journals The pre-history of sustainability reporting: a constructivist reading

2021 ◽  
Vol 34 (9) ◽  
pp. 131-150
Author(s):  
Carlos Larrinaga ◽  
Jan Bebbington
Keyword(s):  
Financial Reporting ◽  
Historical Analysis ◽  
Sustainability Reporting ◽  
Epistemic Communities ◽  
Global Reporting Initiative ◽  
Environmental Reporting ◽  
Content Type ◽  
Time Period ◽  
History Of ◽  
Institutional Actors

PurposeThe aim of this paper is to provide an account of the period prior to the creation of the Global Reporting Initiative (GRI): a body that was critical to the institutionalization of sustainability reporting (SR). By examining this “pre-history,” we bring to light the actors, activities and ways of thinking that made SR more likely to be institutionalized once the GRI entrepreneurship came to the fore.Design/methodology/approachThe paper revisits a time period (the 1990s) that has yet to be formally written about in any depth and traces the early development of what became SR. This material is examined using a constructivist understanding of regulation.FindingsThe authors contend that a convergence of actors and structural conditions were pivotal to the development of SR. Specifically, this paper demonstrates that a combination of actors (such as epistemic communities, carriers, regulators and reporters) as well as the presence of certain conditions (such as the societal context, analogies with financial reporting, environmental reporting and reporting design issues) contributed to the development of SR which was consolidated (as well as extended) in 1999 with the advent of the GRI.Research limitations/implicationsThis paper theorizes (through a historical analysis) how SR is sustained by a network of institutional actors and conditions which can assist reflection on future SR development.Originality/valueThis paper brings together empirical material from a time that (sadly) is passing from living memory. The paper also extends the use of a conceptual frame that is starting to influence scholarship in accounting that seeks to understand how norms develop.

Abstract 177: Hemodynamics and Anatomic Evaluation of Intracranial Arteriovenous Malformations Using Phase-Contrast Magnetic Resonance Velocimetry

Stroke ◽  
2012 ◽  
Vol 43 (suppl_1) ◽  
Author(s):  
Warren Chang ◽  
Benjamin Ciske ◽  
Michael Loecher ◽  
Kevin Johnson ◽  
Yijing Wu ◽  
...  
Keyword(s):  
Arteriovenous Malformations ◽  
Phase Contrast ◽  
Spline Interpolation ◽  
Significant Risk ◽  
Velocity Data ◽  
Scan Time ◽  
Increased Risk ◽  
Significant Difference ◽  
Feeding Vessels ◽  
Risk Of Hemorrhage

Introduction: Arteriovenous Malformations (AVMs) have a high lifetime risk of hemorrhage; however treatment carries a significant risk of morbidity/mortality. Wall Shear Stress (WSS) and other hemodynamic parameters are shown to be altered in patients with symptomatic AVMs. Analysis of hemodynamics may have value in stratifying patients into different risk groups to prioritize treatment. We have recently implemented PC-VIPR, a phase contrast MRA technique that can acquire whole brain angiograms with scan time of 5 minutes with velocity data. PC-VIPR has sufficient spatial resolution for both hemodynamic analysis and assessment of anatomic features such as Spetzler-Martin grading. Materials & Methods: 10 patients with AVMs were scanned using PC-VIPR; WSS and vessel diameter in vessels feeding the AVMs and in normal contralateral vessels were calculated using PC-VIPR velocity data using automated B-spline interpolation. Spetzler-Martin grading was performed by an experienced neuroradiologist. Results: Patients with an asymptomatic presentation or mild symptoms (n=4) had no significant difference in WSS between ipsilateral feeding vessels and normal contralateral vessels (1.555 N/m2 vs 1.494, p=0.31), and showed significant vessel dilation in feeding vessels when compared to normal contralateral vessels (4.57 mm vs 3.66, p=0.005) while patients presenting with hemorrhage, severe headaches/seizures, or focal neurologic deficits (n=6) had significantly higher WSS in feeders compared to contralateral vessels (1.607 N/m2 vs 1.146, p=0.003) but the increase in vessel dilation was not statistically significant. (4.34 vs 3.84, p=0.11) Spetzler-Martin grading was performed in all patients and correlated with grading performed via digital subtraction angiography in all cases. Discussion: In this study we demonstrate that both hemodynamic analysis and Spetzler-Martin grading can be obtained non-invasively in patients with AVMs using PC-VIPR. Variation in WSS between feeders and normal vessels appeared to relate to the clinical presentation of the patient. Figure 1a shows a WSS map of a patient with mild stable symptoms demonstrating similar WSS in feeders compared to contralateral vessels, Figure 1b shows a WSS map of a patient presenting with hemorrhage with higher WSS in feeders compared to contralateral vessels. Several reports suggest high WSS in AVM feeders stimulates compensatory dilation, normalizing WSS. Hemodynamic analysis using PC-VIPR may have value in risk stratification by identifying patients in which compensation has not yet occurred, with increased risk of hemorrhage.

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