Critical Appraisal Topics （Evidence Doer 取向格式)
Title: ONYX is a better embolic agent than NBCA for purely plexiform
brain AVMs
Clinical bottom line:
Endovascular embolization of the purely plexiform brain AVMs with ONYX have significant
higher rate of reduction of the nidus of brain AVM to smaller or equal to 2 cm, compared with
NBCA. Confirmed by a follow-up angiography performed 6 months after the end of the treatment.
Citation/s: Nidal embolization of brain arteriovenous malformations using Onyx in 94 patients
Lead author's name and fax: Mounayer C, Hammami N, Piotin M, Spelle L, Benndorf
G, Kessler I, Moret J.
Clinical Scenario & PICO Question:
情境重點簡述：（與 PICO 有關的為主）
P: patients with brain AVM(arteriovenous malformation)
I/E: endovascular embolization with ONYX(ethylene-vinyl alcohol copolymer)
C: endovascular embolization with NBCA(N-butyl cyanoacrylate)
O: rate of reduction of the nidus of brain AVM to smaller or equal to 2 cm
Type of Question: therapy
Search Terms & Strategy:
Database: Pubmed
Key words & Search stratedy:
#4 Search (N-butyl cyanoacrylate or NBCA) AND (ONYX or ethylene-vinyl alcohol
copolymer) AND (brain or intracranial) Limits: Clinical Trial, Meta-Analysis, Practice
Guideline, Randomized Controlled Trial, Review, Case Reports, Classical Article, Clinical
Trial, Phase I, Clinical Trial, Phase II, Clinical Trial, Phase III, Clinical Trial, Phase IV,
Comparative Study, Controlled Clinical Trial, Corrected and Republished Article, Journal
Article, English 11:19:01 11
#3 Search (N-butyl cyanoacrylate or NBCA) AND (ONYX or ethylene-vinyl alcohol
copolymer) AND (brain or intracranial) Limits: published in the last 5 years, Clinical Trial,
Meta-Analysis, Randomized Controlled Trial, Review, English 11:16:07 3
#2 Search (N-butyl cyanoacrylate or NBCA) AND (ONYX or ethylene-vinyl alcohol
copolymer) AND (brain or intracranial) 11:10:23 12
#1 Search (N-butyl cyanoacrylate or NBCA) AND (ONYX or ethylene-vinyl alcohol
copolymer) 11:08:03 19
The Study: Level of Evidence: 4
1. There were a total of 210 endovascular procedures among the 94 patients (mean, 2.2
procedures per patient); each patient had received at least one injection of Onyx. Onyx
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was used in 138 procedures, either alone (n =88) or in combination with n-BCA (n = 50).
Acrylic glue alone was injected during 72 procedures.
2. Among the 94 patients, there were 53 (56%, 53/94) patients in whom the treatment was
completed; 26 (49%, 26/53) BAVMs were excluded by endovascular procedures alone,
7 (13%,7/53) residual BAVMs were surgically removed, and 20 (38%,20/53) were sent
to radiosurgery after a sufficient reduction of the BAVM size (<2 cm) had been achieved.
For 33 (35%,33/94) patients, the treatment was not completed. Because of the difficult
nidal catheterization in 5 (5%, 5/94) patients, the embolization was targeted to an
assumed epileptogenic area or a hemorrhagic BAVM portion and then stopped.
3. In our series, pure arteriovenous shunt BAVMs were not included because, according to
our criteria, Onyx cannot adequately be injected in such lesions. Most of our BAVMs
were plexiform. They were of mixed type (arteriovenous shunts and plexiform) in only 6
patients.
The Evidence:
1.
the anatomic cure having been confirmed by a follow-up angiography performed 6
months after the end of the treatment. In 13% of the cases, embolization was followed
by surgery and in all but 1 patient (who died during surgery), an angiogram was
performed within 1 week after surgery in which no residual BAVM was seen.
Comments:
1. 事實上, 用 angiography 去評估 brain AVM 體積減少了多少%, 並不是非常準確, 所以
outcome, 以 endovascular embolization 之後剩下的 AVM nidus size 小於或等於 2cm (剛好是
radiotherapy 可以治療的 size) 為標準, 才是比較好的評估方式.
2. 評估治療效果的 study, 樣本數越大, 愈可以避免取樣的 bias, 但是由於 ONYX 是比較新的
產品, 而且 brain AVM 的盛行率小於 1/100,000, 所以每ㄧ家醫學中心的 case 數量並不多.
最好是將來有 multi-center 的大型 study 出現, 會較具有公信力.
3. 要比較 ONYX 和 NBCA, 最好是有 controlled randomized trial, 但是事實上, 兩種
embolic agent 的物理特性本來就不同, 適合治療的 brain AVM indication 也不同, catheter
compatibility 也不同, cost 也不同, 所以要達到 controlled randomized 的條件不是很容易. 所
以目前尚未在 Pub med 上看到 controlled randomized study.
4. Valavanis and Yasargyl reported an overall rate of 40% of anatomic cure in patients with
BAVMs using n-BCA. Nevertheless, the patients were previously selected according to
theBAVMsize, location, and type of arteriovenous shunts constituting the nidus. In this series, a
complete obliteration was achieved in 69% of pure fistulous BAVMs (direct arteriovenous
fistulas) and in 39% of mixed fistulous and plexiform BAVMs; the latter rate fell to 30% in the
case of purely plexiform BAVMs. (Ref 1)
References:
1.
The endovascular treatment of brain arteriovenous malformations. Adv Tech Stand Neurosurg 1998;24:131–14
(LoE: 4)
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2.
The n-BCA Trial Investigators. N-Butyl Cyanoacrylate emblization of cerebral arteriovenous malformation:
results of a prospective, randomized, multi-center trial. AJNR Am J Neuroradiol. 2002;23:748 –755 (LoE: 4)
3.
Brain aneurysms and arteriovenous malformations: advancements and emerging treatments in endovascular
embolization. Stroke. 2007 Apr;38(4):1411-7. Epub 2007 Feb 22. Review. (LoE: 5)
Kill or Update By: Sep. 07, 2010
科部會議名稱：「影像醫學科 EBM style 期刊閱讀」
舉行日期時間：9/07/2009, 0730-0830
報告者：姓名：黃元俊
Code: 129900
指導臨床教師：李國維
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Email: 129900@cch.org.tw