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2007年1月4日——新研究表明，治疗最严重的动静脉畸形并不会造成后继的出血风险。

以Michael P. Marks（医学博士）为首的加利福尼亚斯坦福大学医学中心的研究人员发现，治疗最初表现为出血的Spetzler-MartinⅣ－Ⅴ级的动静脉畸形患者的出血率降低到了无出血症状水平。作者写道：“ 初期治疗并不引起任何统计学意义上的显著性出血率增加。”

研究报道发表在2006年12月28日的《Stroke》上。

更多的动静脉畸形意味着更大的风险吗？

根据研究的背景信息，以前的研究认为治疗大范围的动静脉畸形可能会增加出血的风险。为了确定这种情况是否存在，研究者回顾了1998到2004年间出现Spetzler-MartinⅣ－Ⅴ级的动静脉畸形连续患者的医学报告，以判断治疗前后预期的每年出血概率。这项研究包括61位病人——其中32位男性、29位女性，平均年龄为29.7岁。病人的预治疗期从出现症状到所有定向动静脉畸形治疗包括全部外科切除、形成血管内栓塞或外科放射发挥作用。治疗后期则包括了治疗后一直到现在。平均预处理期为3.49年。

除了现有出血症状的患者外，所有接受预治疗的出血者都进行了出血率计算。治疗后出血率包含所有出血症状，其中也包括治疗本身引起的出血。研究表明，所有先前有出血症状的病人每年预治疗出血率为10.4%－13.9%，而那些没有出血的病人的每年预治疗出血率为7.3%。所有病人的治疗后出血率为每年6.1%：其中包括先前有出血症状的为5.6%，那些没有出血的为6.4%。

需要随机对照研究

作者同时也注意到，在他们对研究对象进行长期和短期出血风险测试时，诊断后的36个月内出血风险为每年12.0%，而之后为每年9.7%。这样发现提示我们“尽管出血率在诊断后可能起初会轻微偏高，但这些大范围存在AVM的患者的后继出血率仍然要比普遍患有动静脉畸形的人群高。他们写道：“因为我们用同样的患者评价预治疗出血风险和治疗后出血风险，所以我们可以认为在这些病人中，治疗并没有带来出血风险的显著性增长。然而，随即对照实验能够完美地回答在这个或者其他动静脉畸形组中的治疗费用问题。”在此期间，他们委托医生对患者继续进行单独治疗以评估这些Ⅳ－Ⅴ级动静脉畸形的病人，同时“出血率作为几种因素中的一种，被用来决定治疗是否提供给不同的病人。”

AVM Treatment Does Not Appear To Increase Hemorrhage Risk

Caroline Cassels

January 4, 2007 — Treating the most serious arteriovenous malformations (AVMs) does not appear to increase subsequent hemorrhage risk, a new study suggests.

Led by Michael P. Marks, MD, researchers at Stanford University Medical Center, in California, found that treating patients with Spetzler-Martin grades 4 and 5 AVMs who initially present with hemorrhage lowers their hemorrhage rate to the level of those with nonhemorrhagic presentation.

"Initiation of treatment does not appear to cause any statistically significant increase in the hemorrhage rate," the authors write.

The study is published online December 28, 2006 in Stroke.

Larger AVMs a Greater Risk?

According to background information in the study, previous research has suggested that treating large AVMs may increase hemorrhage risk.

To determine whether this is the case, the investigators reviewed the medical records of consecutive patients presenting with Spetzler-Martin grades 4 and 5 AVMs between 1998 and 2004 to determine the prospective annual hemorrhage risk before and after treatment.

The study included 61 patients — 32 men and 29 women with an average age of 29.7 years. Patients' pretreatment period included the time from presentation to the initiation of any targeted treatment of the AVM, including total surgical resection, endovascular embolization, or radiosurgery. The posttreatment period included the time from treatment onward. The average pretreatment period was 3.49 years.

With the exception of hemorrhages at presentation, all pretreatment hemorrhages were included in the calculation of the hemorrhage rate. The posttreatment hemorrhage rate included all symptomatic hemorrhages, including those that were attributable to the treatment itself.

The study showed the annual pretreatment hemorrhage rate for all patients was 10.4% — 13.9% in patients with hemorrhagic presentation and 7.3% in those who presented without hemorrhage.

Posttreatment hemorrhage rates were 6.1% per year for all patients: 5.6% for those presenting with hemorrhage and 6.4% in those with nonhemorrhagic presentation.

Need for RCT

The authors also note that when they examined the long- and short-term hemorrhage risk in their study population, the risk of hemorrhage in the first 36 months after diagnosis was 12.0% per year and 9.7% per year thereafter.

This finding suggests "that although the rate of hemorrhage may be slightly higher initially after diagnosis, the rate of subsequent hemorrhage in these larger AVMs remains higher than that in the general AVM population.

"Because we used the same patients to evaluate pretreatment bleeding risk vs posttreatment bleeding risk, we can say that in this patient group, treatment did not confer a statistically significant increased risk of hemorrhage. Nevertheless, a randomized controlled trial would ideally answer the question of the appropriateness of therapy in this or any other AVM group," they write.

In the meantime, they recommend that physicians continue to take an individualized approach to assessment of patients with grades 4 and 5 AVMs and that "the hemorrhage rate presented be one of several factors used to decide whether treatment would be offered on a patient-by-patient basis."

Stroke. 2006. Published online December 28, 2006.

http://www.medscape.com/viewarticle/550257

编辑：蓝色幻想