联合应用超声波与t-PA治疗缺血性脑卒中可以改善预后

根据一项最新研究发现：使用超声波合并应用组织-纤维蛋白溶酶原激活剂(tissue-plasminogen activator, t-PA)，能够改善缺血性脑卒中的预后。该研究比较了联合应用超声波和t-PA与单独使用t-PA的作用与安全性，研究涉及了126例患者。

研究人员评估了使用穿透头颅的多普勒超声波(transcranial Doppler ultrasound, TCD)合并使用t-PA的治疗效果。较早期的研究已经证实在缺血性脑卒中发作后3小时内应用t-PA，能够极大地增加患者完全恢复的几率。但是这个药物不能用于出血性脑卒中的治疗。

一个国际研究小组研究了126例缺血性脑卒中患者；所有患者在卒中发作后3小时内应用了t-PA。其中对照组63例患者仅仅使用t-PA；而其它63例患者使用t-PA，并且在患者使用t-PA之前开始持续使用TCD监测。将一个小设备贴附在患者头颅上用来发送超声波。研究结果发表于2004年11月18日第2204期的《新英格兰医学期刊》(the New England Journal of Medicine)。

结果证实：在持续接受超声波和t-PA的患者中，有49％在治疗后的2小时内，临床情况发生明显改善，很少或者没有血流阻断；而单独使用t-PA的只有30％。值得指出的使，在接受持续TCD和t-PA的患者中，有38％患者被证实2小时内没有发生血流阻断，而单独使用t-PA的只有13％。所有73％接受联合治疗的患者出现完全或者部分的血栓清除，而对照组只有50％。两个治疗组都有4.8％患者发生脑组织出血。脑组织早期血流改善产生了这样的趋势：超过13.5％的接受持续TCD和t-PA治疗的患者在脑卒中发作后3月内完全恢复。

这些科学家还发现：在治疗后2小时内完全清除血凝块的患者，其语言、机体力量、以及其它受到脑卒中影响的功能获得恢复的几率最大。研究人员将该研究称为 "联合穿越头颅超声波以及系统使用t-PA治疗所产生的缺血性脑卒中的血栓裂解"(Combined Lysis of Thrombus in Brian Ischemia Using Transcranial Ultrasound and Systemic t-PA, CLOTBUST)

“在过去30年中，世界范围内的科学家已经证实超声波是一项快速、温和以及有效的裂解血凝块的方法。我们是首次在患者中证实了其疗效。这种方法增加了流向脑组织的血流，改善了临床预后，并且有利于患者的护理者，”该项研究的负责人Andrei Alexdrov医学博士说。他是德克萨斯-休斯顿大学医学院神经病学副教授。

美国国立神经系统疾病与脑卒中研究院(NINDS; Bethesda, MD., USA)主任Story C. Landis博士评论说：“脑卒中对患者以及他们的护理者而言都是后果严重的。这些初步结果提示：在缺血性脑卒中发作之后患者接受联合治疗能够给医院更多机会。这是一项鼓舞人心的进步，将改进目前的治疗方法并促使疾病向好的方向发展。”该研究获得了NINDS的部分资助。

超声波能够使血栓组织内的分子产生振动，从而可以为t-PA创造更多的结合位点，促使血凝块崩解。研究人员相信：与单独应用t-PA相比较，这种分子振动促使药物运输至血凝块内以及周围，从帮助开放更多的阻断血管。

Ultrasound Plus t-PA Improves Stroke Outcome
 
Utilizing ultrasound combined with the drug tissue-plasminogen activator (t-PA) can improve the outcome of an ischemic stroke, according to a new study. The study compared the efficacy and safety of ultrasound with t-PA vs t-PA only in a trial involving 126 patients.

The investigators evaluated the effectiveness of using transcranial Doppler ultrasound (TCD) in combination with t-PA. Earlier studies have demonstrated that t-PA, when administered within three hours of onset of ischemic stroke, can greatly improve a patient’s likelihood of a full recovery. This agent, however, cannot be used to treat a typical hemorrhagic stroke.

An international group of investigators examined 126 patients who suffered an ischemic stroke; all patients received t-PA within three hours after stroke onset. The 63 patients in the control group received t-PA alone, while the other 63 patients received the agent in combination with continuous TCD monitoring that began right before the patients received t-PA. A small device attached to a head frame was used to deliver the ultrasound waves. The study was published in the November 18, 2204, issue of the New England Journal of Medicine.

Results demonstrated that 49% of patients who received continuous ultrasound and t-PA showed drastic clinical improvement and little or no blockage within two hours after therapy began compared to 30% of patients who received t-PA alone.

Remarkably, 38% of the patients who received continuous TCD and t-PA demonstrated no blockage within two hours, compared to 13% who received t-PA alone. All 73% of patients who received the combined therapy demonstrated total or partial clearance of the thrombus, compared to 50% in the control group. Bleeding into the brain was seen in 4.8% of patients in both groups. This early improvement of blood flow to the brain resulted in a trend by which 13.5% more patients who received continuous TCD and t-PA had recovered completely by three months after stroke.

The group of scientists also discovered that patients who had complete clearance of their clot within two hours following treatment had the greatest probability of regaining speech, body strength, and other functions affected by stroke. The nvestigators called the trial CLOTBUST (Combined Lysis of Thrombus in Brian Ischemia Using Transcranial Ultrasound and Systemic t-PA).

“In the past 30 years, scientists around the world have shown that ultrasound is fast, gentle, and effective in helping t-PA to break up clots. For the first time, we have demonstrated this benefit in patients. This approach enhances flow to the brain and augments clinical recovery and their caregivers,