加压设备可预防DVT 挽救卒中患者生命

伦敦——CLOTS3大型随机试验结果表明，对曾发生卒中的制动患者实施间歇性充气加压(IPC)可使近端深静脉血栓形成(DVT)的绝对风险降低3.6%：间歇性充气加压组患者30天近端DVT发生率为8.5%，而单纯常规卒中后护理组为12.1%(P=0.001)，校正后危险比为0.65；6个月时IPC组患者的死亡风险也较单纯常规护理组下降14%(P=0.042)；IPC似乎在多个预设的亚组患者中均很有效，包括缺血性卒中和出血性卒中。上述结果于2013年5月31日在线发表于《柳叶刀》(doi: 10.1016/S0140-6736(13)61050-8)，并且同步在欧洲卒中大会上公布。

Martin Dennis医生正在对一名卒中患者使用IPC装置。

主要研究者、爱丁堡大学临床神经科学系及苏格兰爱丁堡西部总医院的Martin Dennis医生认为这是一项惊人的发现。伦敦盖氏与圣托马斯的NHS信托基金会的卒中顾问、皇家内科医学院校际卒中研究组组长Tony Rudd医生称此研究是一项重大突破，向人们展示了一种简单而安全的治疗如何能挽救患者的生命，并表示目前面临的挑战是如何保证所有可能受益的患者都能享受到这项治疗，这项研究也是近年来卒中治疗领域出现的最重要调查研究之一。英格兰基尔大学斯托克分校卒中医学顾问、医学教授Christine Roffe医生也对该研究的结果给予褒奖。

CLOT 3研究简介

CLOTS 3是CLOTS(卒中后腿部血栓与加压袜)试验联合小组进行的前2项试验的后续。在这项试验中，研究者们探讨了加压袜用于曾发生卒中的患者是否能预防栓塞并发症。不过，CLOTS 1试验(Lancet 2009;373:1958-65)和CLOTS 2试验的结果均为阴性，未观察到卒中患者使用加压袜的益处。

在2008年12月~2012年9月期间，总共有2,876例患者被招募到CLOTS 3试验中。受试者必须处于制动状态，并且在发生卒中的0~3天内接受随机化分组。制动定义为在没有他人帮助的情况下无法走到浴室。受试者被随机分配接受单纯的常规卒中后护理，或在此基础上联合实施IPC(采用Covidien公司生产的 Kendall SCD 快速连续加压设备)。联合治疗组包括穿戴与大腿等高的可充气袖带30天，在此期间，该设备可依据患者的体位自动实施IPC。平均穿戴时程及中位时程分别为12.5天和9.0天。在7~10天使用多普勒超声评估DVT，如果有可能的话，在25~30天时再测1次。两组患者均穿加压袖带，以确保超声技师对治疗分组不知情。在6个月时进行随访，方法为向患者的初级保健医师邮寄调查问卷，询问有关出院后生命体征及静脉血栓栓塞发生的情况。对患者也邮寄一份问卷，如果没有回应就打电话询问。

对30天近端DVT的影响是主要结局指标，但与常规护理相比，IPC还降低了症状性DVT(6.3% vs. 4.6%；P=0.0045)及任何类型DVT(21.1% vs. 16.2%；P=0.001)的发生率。肺栓塞发生率无明显的组间差异(2.4% vs. 2.0%；P=0.453)。在安全性方面，两组在因持续穿加压袖带而跌倒受伤或骨折的例数方面无显著差异，在皮肤溃疡发生率方面也无显著差异(1.4% vs. 3.1%；P=0.002)，而且对数据进行仔细检查后发现仅10例(0.7%)是由IPC所致。

正常情况下手术患者只是短期应用这些袖带，但在此项试验中研究者延长了其使用时间，因此厂家专门生产了一种更柔软的袖带。有部分患者感觉这种袖带不舒服、太热，或是使用时“太吵”，但“对因卒中而制动的患者实施间歇性充气加压可降低深静脉栓塞的风险”。Dennis医生强调：“对卒中患者实施IPC具有可行性，并且相对安全。IPC可有效减少卒中后静脉血栓栓塞的发生，每预防1例近端DVT需治疗大约28例患者。”另外，这种方法也可以提高整体生存率，在30天内预防1例死亡需治疗43例患者。

Dennis医生、Rudd医生及 Roffe医生无相关利益冲突披露。爱丁堡大学及NHS Lothian发起了本研究，资金来自苏格兰政府首席科学家办公室、国立卫生研究院卫生技术评估规划及苏格兰卒中研究网。本研究所使用的设备由Covidien公司免费提供。

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By: SARA FREEMAN, Internal Medicine News Digital Network

LONDON – Intermittent pneumatic compression reduced the absolute risk of proximal deep vein thrombosis in patients who had suffered a stroke and were immobile by 3.6% in a large, randomized trial.

The incidence of proximal DVT at 30 days in the CLOTS 3 study was 8.5% with intermittent pneumatic compression (IPC) and 12.1% with routine poststroke care alone (P = .001). The adjusted odds ratio was 0.65.

Dr. Martin Dennis tests stroke patient Yvette Henderson with an intermittent pneumatic compression device to prevent poststroke deep vein thrombosis.
 
There was also a 14% reduction in the risk of death seen at 6 months favoring IPC use over routine care alone (P = .042). This was a surprising finding, said principal investigator Dr. Martin Dennis of the University of Edinburgh’s clinical neurosciences division and Western General Hospital in Edinburgh, Scotland.

Importantly, IPC appears to be effective across a variety of prespecified subgroups, including both ischemic and hemorrhagic stroke.

Findings will change practice

The findings, which were published online in the Lancet (2013 May 31 [doi: 10.1016/S0140-6736(13)61050-8]) to coincide with their presentation at the annual European Stroke Conference, are practice changing and suggest that national stroke guidelines need to be updated.

"This study is a major breakthrough, showing how a simple and safe treatment can save lives," Dr. Tony Rudd, a consultant stroke physician at Guy’s and St. Thomas’ NHS Foundation Trust, London, said in a statement issued by the University of Edinburgh.

"The challenge now will be to ensure that all patients who might benefit are offered treatment," added Dr. Rudd, who chairs the Royal College of Physicians’ Intercollegiate Stroke Working Party. "It is one of the most important research studies to emerge in the field of stroke in recent years," he noted.

Dr. Christine Roffe, consultant in stroke medicine and professor of medicine at Keele University in Stoke-on-Trent, England, also praised the study’s results. "That something as simple as a compressive sleeve saves lives after stroke is fascinating," she said in an interview at the conference. Dr. Roffe was not involved in the study.

The CLOTS 3 study

CLOTS 3 follows on from two other trials performed by the CLOTS (Clots in Legs or Stockings after Stroke) Trials Collaboration, in which compression stockings were examined as a possible means of preventing thrombotic complications in patients who had suffered a stroke. Results of CLOTS 1 (Lancet 2009;373:1958-65) and CLOTS 2 were negative, however, and no benefit of compression stockings was seen in stroke patients.

Between December 2008 and September 2012, a total of 2,876 patients were enrolled in CLOTS 3. For inclusion, patients had to be immobile and randomized within 0-3 days of having had a stroke. Immobility was defined as being unable to walk to the bathroom without the help of another person.

Patients were randomized to receive either routine poststroke care alone or with additional IPC delivered by Covidien’s Kendall SCD Express Sequential Compression System. The latter involved wearing thigh-high, inflatable sleeves continuously for up to 30 days, during which time the device automatically provided IPC depending on the position of the patient. The mean and median durations of wear were 12.5 days and 9.0 days, respectively.

DVT was assessed using duplex ultrasound at 7-10 days and again at 25-30 days if possible. Both patient groups wore compression sleeves to ensure that the ultrasound technicians remained blinded to the treatment group. Follow-up was at 6 months via postal questionnaires sent to patients’ primary care physicians asking about vital status and the occurrence of venous thromboembolism since hospital discharge. Patients were also sent a postal questionnaire and telephoned if they did not respond.

DVT risk reduced

The effect on proximal DVT at 30 days was the primary outcome measure, but IPC also reduced the incidence of symptomatic DVT (4.6% vs. 6.3%; P = .0045) and any DVT (16.2% vs. 21.1%; P = .001) versus routine care. There was no significant difference in the incidence of pulmonary embolism between study arms (2.0% vs. 2.4%, respectively, P = .453).

In terms of safety, there was no difference between the treatment groups in the number of falls with injury or fractures as a result of constantly wearing the compression sleeves. There was a significant difference in skin ulcers (3.1% with IPC vs. 1.4% without, P = .002), but close inspection of the data suggested that only 10 (0.7%) cases were due to IPC.

"During the study, [the manufacturers of the IPC device] brought out a new comfort sleeve," Dr. Dennis noted in an interview.

"Normally these sleeves were being used for short periods in surgical patients, but we were using them for longer periods, so they brought out a softer sleeve," he observed. Anecdotally, he conceded that some people found the sleeves uncomfortable, too hot, or the system "noisy" to use.

The bottom line is that "intermittent pneumatic compression in people who are immobile with stroke reduces the risk of deep vein thrombosis," Dr. Dennis said.

He emphasized that "IPC is feasible in stroke patients, and it is relatively safe. It is an effective means of reducing venous thromboembolism after stroke, with a number needed to treat of about 28 for proximal DVT."

Intriguingly, it may also improve overall survival, "although we weren’t expecting to see that effect," Dr. Dennis said. The number needed to treat to prevent 1 death in 30 days was 43.

Dr. Dennis, Dr. Rudd, and Dr. Roffe had no relevant disclosures. The University of Edinburgh and NHS Lothian sponsored the study with funding from the Chief Scientist Office of the Scottish Government, the National Institute of Heath Research Health Technology Assessment Programme, and the Scottish Stroke Research Network. Covidien provided the equipment used in the study free of charge.