Unruptured cerebral arteriovenous malformation [Neurosurgery Wiki]

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====== Unruptured cerebral arteriovenous malformation ======

==== Natural History ====
A precise assessment of angioarchitecture characteristics using non-invasive imaging is helpful for serial follow-up and weighting the risk of [[natural history]] in unruptured [[cerebral arteriovenous malformation]].

A [[study]] aimed to test the [[hypothesis]] that [[susceptibility weighted imaging]] ([[SWI]]) would provide an accurate [[evaluation]] of angioarchitectural features of unruptured bAVM..

A total of 81 consecutive patients with unruptured bAVM were examined. Image quality of SWI for the assessment of bAVM angioarchitectural features were determined by a five-point scale. The accuracy of SWI for detection of angioarchitectural features was evaluated using DSA as a standard reference. And further compared among unruptured bAVMs with or without silent intralesional microhemorrhage on SWI to examine the potential confounding effect of microhemorrhage on image analysis.


All lesions were identified on SWI. Image quality of SWI was judged to be at least adequate for diagnosis (range, 3-5) in all patients by both readers. Using DSA as reference standard, the area under receiver operating curve (AUC) of detection of deep or posterior fossa location, exclusively deep venous drainage, venous ectasia, venous varices and the presence of associated aneurysm on SWI was 1, 0.93, 0.94, 0.95, and 0.83, respectively. Silent intralesional microhemorrhage were detected in 39 patients (48.15%) on SWI and no significant difference (P > 0.05) was found in angioarchitectural features between cases with and without silent microhemorrhage.

[[SWI]] might be a non-invasive alternative technique for angiogram in the angioarchitectural assessment of unruptured bAVM
((Wu CX, Ma L, Chen XZ, Chen XL, Chen Y, Zhao YL, Hess C, Kim H, Jin HW, Ma J.
Evaluation of Angioarchitectural Features of Unruptured Brain Arteriovenous
Malformation by Susceptibility Weighted Image (SWI). World Neurosurg. 2018 May
30. pii: S1878-8750(18)31105-7. doi: 10.1016/j.wneu.2018.05.151. [Epub ahead of
print] PubMed PMID: 29859363.
)).

====Trials====

[[ARUBA]] (A Randomized Trial of Unruptured Brain Arteriovenous Malformations).

[[Scottish Audit of Intracranial Vascular Malformations]]
====Treatment====

see [[Unruptured cerebral arteriovenous malformation treatment]].

====Outcome====
Uncertainty exists also concerning the benefit of therapy with regard to [[headache]], epilepsy, and quality of life (QoL) in unruptured AVMs. 

==== Complications ====

see [[Ruptured cerebral arteriovenous malformation]].

===== Unruptured cerebral arteriovenous malformation rupture risk =====

[[Unruptured cerebral arteriovenous malformation rupture risk]].



====Radiosurgery====
see [[Cerebral arteriovenous malformation radiosurgery]]


====Case series====

Fully [[automated segmentation]] via unsupervised classification with [[fuzzy c-means clustering]] was used to analyze [[AVM]] [[nidus]] on [[T2]]-weighted [[magnetic resonance imaging]]. The proportions of [[vasculature]], brain [[parenchyma]], and [[cerebrospinal fluid]] (CSF) were quantified. This was compared to [[manual segmentation]]. Association between brain parenchyma component and [[radiation]]-induced changes (RICs) development was assessed.

The proposed [[algorithm]] was applied to 39 unruptured AVMs. This included 17 female and 22 male patients with a median age of 27 years. The median percentages of the constituents were as follows: vasculature (31.3%), brain parenchyma (48.4%), and CSF (16.8%). RICs were identified in 17 (43.6%) of 39 patients. Compared to manual segmentation, the automated algorithm was able to achieve a Dice [[similarity index]] of 79.5% (sensitivity=73.5% and specificity=85.5%). RICs were associated with higher proportions of intervening nidal brain parenchyma (52.0% vs. 45.3%, p=0.015). Obliteration was not associated with a higher proportions of nidal vasculature (36.0% vs. 31.2%, p=0.152).

The [[automated segmentation]] [[algorithm]] was able to achieve classification of AVM nidus components with relative accuracy. Higher proportions of intervening nidal brain parenchyma were associated with RICs
((Lee CC, Yang HC, Lin CJ, Chen CJ, Wu HM, Shiau CY, Guo WY, Hung-Chi Pan D, Liu
KD, Chung WY, Peng SJ. Intervening nidal brain parenchyma and risk of
radiation-induced changes after radiosurgery for brain arteriovenous
malformation: a study using unsupervised machine learning algorithm. World
Neurosurg. 2019 Jan 21. pii: S1878-8750(19)30103-2. doi:
10.1016/j.wneu.2018.12.220. [Epub ahead of print] PubMed PMID: 30677586.
)).
===2015===
A series of 97 microsurgically resected unruptured brain AVM was analyzed in terms of postoperative morbidity and lifetime loss of quality-adjusted life-years (QALY). For comparison, the natural risk of becoming disabled was modeled on the basis of published data.

Discharge morbidity was recorded in 11 of the 69 of Spetzler-Martin (SM) grade 1 and 2 AVMs (16 %), eight of 22 (36 %) grade 3, and four of six grade 4 (67 %), permanent morbidity >mRS 1 in 3 (4.3 %) grade 1 and 2, four (18 %) grade 3, and three (50 %) grade 4. Treatment inflicted loss of QALY amounted to 0.5 years for SM grade 1-2, 2.5 years grade 3, 7.3 years for grade 4. For the SM grades 1 and 2, the treatment-related loss of 0.5 QALY was met by the natural course after 2.7-4.3 years. For the Spetzler-Martin grades 3 and 4, the treatment-induced loss QALY was not met by the natural risk within a foreseeable time. Permanent morbidity and treatment inflicted loss of QALY of patients younger than 39 years was lower than that of older patients (7 vs. 15 % and 1.0 vs. 2.1 QALY).

Microsurgically managed SM grades 1 and 2 fared better than the modeled natural course but grades 3 and 4 AVM did not benefit from surgery. Younger patients appear to fare more favorably than older patients
((Steiger HJ, Fischer I, Rohn B, Turowski B, Etminan N, Hänggi D. Microsurgical 
resection of Spetzler-Martin grades 1 and 2 unruptured brain arteriovenous
malformations results in lower long-term morbidity and loss of quality-adjusted
life-years (QALY) than conservative management-results of a single group series. 
Acta Neurochir (Wien). 2015 Sep;157(8):1279-87. doi: 10.1007/s00701-015-2474-9.
Epub 2015 Jul 7. PubMed PMID: 26144566.
)).

===2014===
For 427 consecutively enrolled [[patient]]s with ucAVMs in a database that included patients who were conservatively managed. Kaplan-Meier analysis was performed on patients observed for more than 1 day to determine the risk of [[hemorrhage]]. Variables that may influence the risk of first hemorrhage were assessed using Cox proportional hazard regression models and Kaplan-Meier life table analyses from referral until the first occurrence of the following: hemorrhage, treatment, or last review. The outcome from surgery (leading to a new permanent neurological deficit with last review [[modified Rankin Scale]] [mRS] score > 1) was determined. Further sensitivity analysis was made to predict risk from surgery for the total ubAVM cohort by incorporating outcomes of surgical cases as well as cases excluded from surgery because of perceived risk, and assuming an adverse outcome for these excluded cases. 

Results A total of 377 patients with a ubAVM were included in the analysis of the risk of hemorrhage. The 5-year risk of hemorrhage for ubAVM was 11.5%. Hemorrhage resulted in an mRS score > 1 in 14 cases (88% [95% CI 63%-98%]). Patients with [[Spetzler Ponce Classification]] Class A ubAVMs treated by surgery (n = 190) had a risk from surgery of 1.6% (95% CI 0.3%-4.8%) for a permanent neurological deficit leading to an mRS score > 1 and 0.5% (95% CI < 0.1%-3.2%) for a permanent neurological deficit leading to an mRS score > 2. Patients with Spetzler-Ponce Class B ubAVMs treated by surgery (n = 107) had a risk from surgery of 14.0% (95% CI 8.6%-22.0%) for a permanent neurological deficit leading to an mRS score > 1. Sensitivity analysis of Spetzler-Ponce Class B ubAVMs, including those in patients excluded from surgery, showed that the true risk for surgically eligible patients may have been as high as 15.6% (95% CI 9.9%-23.7%) for mRS score > 1, had all patients who were perceived to have a greater risk experienced an adverse outcome. Patients with Spetzler-Ponce Class C ubAVMs treated by surgery (n = 44) had a risk from surgery of 38.6% (95% CI 25.7%-53.4%) for a permanent neurological deficit leading to an mRS score > 1. Sensitivity analysis of Class C ubAVMs, including those harbored by patients excluded from surgery, showed that the true risk for surgically eligible patients may have been as high as 60.9% (95% CI 49.2%-71.5%) for mRS score > 1, had all patients who were perceived to have a greater risk experienced an adverse outcome. Conclusions Surgical outcomes for Spetzler-Ponce Class A ubAVMs are better than those for conservative management
((Bervini D, Morgan MK, Ritson EA, Heller G. Surgery for unruptured
arteriovenous malformations of the brain is better than conservative management
for selected cases: a prospective cohort study. J Neurosurg. 2014 Aug 8:1-13.)).