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并用 CABG 和 CEA增加了死亡与中风风险

来源:WebMD
摘要:一篇新的研究显示,并用冠动脉绕道术(CABG)和颈动脉内膜切除术(CEA)的病患,在术后死亡或中风风险比只用CABG的病患增加38%。Dubinsky医师在一篇发表于美国神经医学会(AAN)的声明中表示,如此并用手术有无好处是有争议的,基于此一显著增加术后中风和死亡的现象,需要进行并用两种手术的随机临床试验以确认治疗利益,且......

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  January 16, 2007 — 一篇新的研究显示,并用冠动脉绕道术(CABG)和颈动脉内膜切除术(CEA) 的病患,在术后死亡或中风风险比只用CABG的病患增加38%。
  
  该研究的作者,堪萨斯大学医学中心的Richard M. Dubinsky医师在一篇发表于美国神经医学会(AAN)的声明中表示,如此并用手术有无好处是有争议的,基于此一显著增加术后中风和死亡的现象,需要进行并用两种手术的随机临床试验以确认治疗利益,且要比较不同住院期间的手术。
  
  另一篇报告认为,由于一些不适当的原因,颈动脉内膜切除术的数量已渐渐减少,该篇的作者由Mount Sinai医学院的Ethan A. Halm医师领衔,作者们认同随机动脉内膜切除术试验的指标性改善结果,但是表达所观察到的一些无症状病患接受CEA手术后所得到的治疗利益低的现象。
  
  两篇研究都刊登于1月15日的神经学(Neurology)期刊。
  
  【并用手术增加,危险吗?】
  第一篇报告中,Dubinsky医师和同事使用全国住院病患样本的资料,以美国所有紧急住院的案例中的20%作为代表样本,比较并用CABG和CEA的病患,与只用CABG的病患在术后的住院死亡率或中风风险。
  
  作者指出,并用手术是希望保护颈动脉循环,以免于CABG时发生动脉到动脉栓塞中风,以及减少分别手术时的麻醉风险,虽然并用手术会比较久。
  
  他们在这篇分析中发现,在研究期间,并用CABG和CEA 的比率从1993的1.1%增加到2002的1.58%;在校正共病症后,接受并用手术的病患,在术后死亡或中风风险比只用CABG的病患增加38%。
  
  并用 CEA-CABG的病患和只用CABG的病患之术后死亡或中风风险比较

终点

风险比

95% CI

P

并用 CEA-CABG

1.38

1.27 – 1.50

< .001

只用 CEA

0.49

0.48 – 0.51

< .001


  他们指出,看起来是女性在术后比较有保护效果。
  
  作者们结论指出,并用CEA-CABG的频率增加,但是一系列的报告仍不足以结论并用手术是否有好处;需要一个随机临床试验,将颈动脉狭窄的程度和预防中风的程度加以分类,并追踪至少一年, 以清楚厘清颈动脉和冠状动脉粥状硬化病患并用CEA-CABG之治疗利益。
  
  Alberta大学的Thomas E. Feasby医师和Robarts研究中心的Henry J.M. Barnett医师在编辑评论中表示,此一额外的风险比最近的其他研究所报告的低,但是对无症状的颈动脉狭窄病患并用这两种手术仍应注意。
  
  基于并用手术的频率(2002年所有的CEA中有1.58% ),应只让有经验的专家小心操作,直到有随机控制试验证实有效为止。
  
  【改善适用程度】
  在他们的另一篇报告中,Halm 医师和同事评估怎样才适用CEA及其适应症,这些事项在1990年代后期所发表的主要CEA试验,如“北美地区有症状颈动脉内膜切除术试验 (NASCET) ”和“无症状颈动脉粥状硬化研究 (ACAS)”中已有所改变。
  
  这些试验起源于对1981年的RAND健康服务利用研究的回应,认为在医疗机构所进行的CEA手术有32%是用错适应症;最近的这篇“纽约颈动脉手术(NYCAS)研究”,评估了1998年1月到1999年6月间,纽约老年病患的9,588 件CEA手术的适用性。
  
  详细的资料是从医疗纪录摘录,并和CEA的1557种适应症相比较;作者们报告指出,大部分的手术是基于合适的适应症下进行,仅有8.6%被认为是不合适的,显然地,比第一篇RAND研究所指的32%低。
  
  适合CEAs的与不适合的或不确定的比较

 

CEA 手术百分比

适合的

87.1

不确定的

4.3

不适合的

8.6


  最常见的不适合手术的理由是,无症状病患的高共病症、大中风后手术,或用于极微小程度的狭窄。
  
  将近四分之三的病患(72.3%)接受CEA 治疗无症状的狭窄,而有18.6%出现 TIA,9.1%发生中风。
  
  Halm 医师在一篇 AAN的声明中表示,好消息是,随着谁适合接受颈动脉内膜切除术医疗研究的大众投资,可以降低许多因为不适当原因所进行的手术;坏消息则是,对那些动脉阻塞但无症状的病患来说,手术的治疗利益比其他病况者低。
  
  【细节才容易出现严重问题】
  同一篇编辑评论中,Feasby 和Barnett两位医师也表达对无症状病患高度使用手术的关怀;他们指出,尽管 ACAS 显示狭窄严重的病患进行手术有好处,该研究的绝对风险降低是基于ACAS组的手术前后中风率仅有2.3%。
  
  这让ACAS 的结果成为“最佳方案”,因为Halm 等人研究中的并发症比率为3% ,其他一些美国的报告则是4.5% — 也就是说,无症状的病患接受药物治疗而非手术治疗,将可以存活且不会有中风风险。
  
  他们结论指出,Halm 等人的研究结果显示,适当的CEA和1980年代相比,看似可以有令人满意的改善, 至于无症状者的手术则应考虑。
  
  NYCAS研究接受联邦健康照顾研究与品质管理局、医疗照顾与医疗服务中心、和Robert Wood Johnson基金会等之赞助。

Risk for Death, Stroke Increased with Combined CABG and CEA

By Susan Jeffrey
Medscape Medical News

January 16, 2007 ??A new study shows an increased risk for death or postoperative stroke of about 38% among patients undergoing combined coronary artery bypass grafting (CABG) and carotid endarterectomy (CEA) vs CABG alone.

"The benefit of this combined procedure is controversial," said study author Richard M. Dubinsky, MD, from the University of Kansas Medical Center, in Kansas City, in a statement from the American Academy of Neurology (AAN). "Given this significant increase in postoperative stroke and death, a randomized clinical trial of the combined surgery is needed to determine the benefit, if any, compared with performing the operations in separate hospitalizations."

A separate report suggests a reduction over time in the number of carotid endarterectomy procedures thought to be done for inappropriate reasons. The authors, led by Ethan A. Halm, MD, from Mount Sinai School of Medicine, New York, credit results of the landmark randomized endarterectomy trials for this improvement but express concern about an observed increase in CEA in asymptomatic patients, where, they note, the net benefit from surgery is low.

Both studies are published in the January 15 issue of Neurology.

Combined Procedure More, Not Less, Dangerous?

In the first report, Dr. Dubinsky and colleagues used data from the Nationwide Inpatient Sample, representing a stratified sample of 20% of all US acute hospital admissions, to compare the rates of hospital mortality and postoperative stroke in patients undergoing combined CEA and CABG vs those rates with CABG alone.

The hope with the combined procedure is to protect the carotid circulation from artery-to-artery embolic stroke during CABG and to lessen the risk by having just 1 operation with a single exposure to anesthesia, even though the combined operation is longer, the authors note.

In this analysis, they found that the proportion of CABG procedures combined with CEA grew over the study period of interest, from 1.1% in 1993 to 1.58% in 2002. After adjustment for comorbidities, patients who received both procedures had a 38% increased risk for the combined outcomes of death and postoperative stroke compared with CABG alone.

Combined Death and Postoperative Stroke with Combined CEA-CABG vs CABG Alone

End Point

Odds Ratio

95% CI

P

Combined CEA-CABG

1.38

1.27 ??1.50

< .001

CEA only

0.49

0.48 ??0.51

< .001


There was some suggestion that being female conferred a protective effect in terms of outcome, among the first times this has been seen, they point out.

"The frequency of combined CEA-CABG has increased, but the reported case series are inadequate to conclude whether there is a benefit to combining the procedures," the authors conclude. "A randomized controlled clinical trial, stratified for the degree of carotid stenosis and for previous stroke, with a follow-up of at least 1 year, is clearly needed to determine the benefit, if any, of combined CEA-CABG in patients with carotid and coronary atherosclerosis."

In an accompanying editorial, Thomas E. Feasby, MD, from the University of Alberta, in Edmonton, and Henry J.M. Barnett, MD, from the Robarts Research Institute, in London, Ontario, write that this additional risk is lower than has been reported in some other recent studies but "still suggests caution in combining these 2 procedures for what is usually asymptomatic carotid stenosis.

"Given the frequency of the combined procedures (1.58% of all in 2002), this is a situation suitable for cautious use in the hands of experienced experts until it is proven efficacious in a randomized controlled trial," they conclude.

Improving Appropriateness

In their separate report, Dr. Halm and colleagues assessed how appropriateness and indications for CEA have changed since publication of the major CEA trials during the late 1990s, including the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and the Asymptomatic Carotid Atherosclerosis Study (ACAS).

Those trials were launched in response to the RAND Health Service Utilization Study in 1981, suggesting that 32% of CEA procedures performed in Medicare beneficiaries were done for inappropriate indications. The current study, the New York Carotid Artery Surgery (NYCAS) study, assessed appropriateness in 9588 CEA procedures done between January 1998 and June 1999 among elderly patients in New York State.

Detailed data were abstracted from medical records and compared with a list of 1557 indications for CEA. The authors report that the vast majority of the procedures were done for reasons deemed appropriate; only 8.6% were thought to be inappropriate, down significantly from 32% in the first RAND study.

Proportion of CEAs Considered Appropriate vs Uncertain or Inappropriate


Percentage of CEA Procedures

Appropriate reasons

87.1

Uncertain reasons

4.3

Inappropriate reasons

8.6


The most common reasons that surgery was deemed inappropriate were high comorbidity in asymptomatic patients; operating after a major stroke; or for only minimal stenosis.

Nearly three quarters of patients, 72.3%, underwent CEA for asymptomatic stenosis, while 18.6% had had a TIA and 9.1% a stroke.

"The good news is following the large public investment in medical research on who should undergo carotid endarterectomy, there's been a large reduction in the number of patients undergoing the procedure for inappropriate reasons," Dr. Halm said in a statement from the AAN. "The bad news is there's been a shift toward operating predominantly on patients with no symptoms from the blocked arteries, where the benefit from surgery is lower and is reduced further for patients with other medical conditions."


Devil in the Details

In the same editorial, Drs. Feasby and Barnett also express concern about the high use of the procedure in asymptomatic patients. Although ACAS showed a benefit from surgery in patients with high-grade stenosis, the absolute risk reduction in that study was based on the ACAS group's perioperative stroke rate of only 2.3%, they point out.

This makes the ACAS result a "best-case scenario," because the complication rate in the study by Halm et al was 3% and in another recent report in 10 US states was 4.5% ??a level at which patients would have been more likely to survive without stroke if they received medical, not surgical, intervention.

"Consequently, while the results of the Halm et al study that the appropriateness of seems to have improved markedly compared with the 1980s is gratifying, the trend toward operating on predominantly asymptomatic cases is concerning," they conclude.

The NYCAS study was supported by the federal Agency for Healthcare Research and Quality, Centers for Medicare & Medicaid Services, and the Robert Wood Johnson Foundation.


Neurology 2007;187-194, 195-197, 172-173.

作者: Susan Jeffrey 2007-6-20
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