PREPARE的主要终点是一段时间的ST段回落。次要终点是TIMI血流分级、心肌灌注分级、远端栓塞血管造影指标以及在30天时的全因死亡、心肌梗死、靶血管再血管化和中风。

      30天时的不良反应包括在两组当中每组都出现了2例死亡。Proxis组中出现了2例心肌梗死，对照组是3例。Proxis组3例靶血管再血管化，对照组是6例。MACCE在Proxis组发生了6次，对照组10次。对照组还发生了1例中风。在Proxis着陆区没有并发症发生，Koch医生这样说。

优点与局限
      来自Royal Oak, Mich. William Beaumont 医院的Cindy L. Grines医生说PREPARE研究具有一些优势。它是随机的，它应用了两个有经验的中心，且装置本身还可以避免只有远端封堵球囊和过滤装置才会发生的问题。此外，研究者在再灌注时间方面用了最少的延误（3分钟）。而且还有TIMI3改进的趋势以及快速ST段回落的改善。

      她还说到，“很有趣的是，Proxis装置被证明非常安全。没有并发症发生，在94%的病例中它都可以被应用并且在清除血栓方面有效率达到了75%。”

      有一点缺陷，那就是近端保护的经验。此外，相对较小的样本量不允许临床终点得以评估。

研究细节
      在Proxis组当中患者的平均年龄是62岁，对照组是59岁。两组中80%都是男性。录用标准由以下组成：持续时间小于6小时的STEMI患者， ST段抬高的高度大于2 mm，TIMI血流分级在第一次血管造影时为0-1的，冠脉解剖适于Proxis，以及心电图适与ST段回落评估的患者。据Koch博士说，如果患者先前有CABG或者在重复部位发生过重复性心肌梗死或者梗死溶解的，那么他们将被排除出该研究。

      这是一个非常独特的装置，她说，这项试验增加了我们正在该领域开始积累的信息财富。

(医心评论：孟祥飞 译  陆卫 校）

PREPARE: Proxis System Feasible, Safe in STEMI

Key Points:
Device led to better immediate microvascular flow.

By TCT Daily Staff

Early complete ST-segment resolution was better in STEMI patients treated with the proximal embolic protection device Proxis compared with controls, according to the results of the PREPARE study.

The difference in ST-segment resolution immediately after primary PCI was statistically significant (P=.009), said Karel T. Koch, MD, PhD (left), from the Academic Medical Center, University of Amsterdam, The Netherlands.

Immediate ST-segment resolution was 66% in the Proxis group vs. 50% in the control group. At 60 min, ST-segment resolution was 80% in the Proxis group vs. 72% in controls (P=.14). and at 90 min, it was 81% in the Proxis group and 74% in controls (P=.23). At 120 min, ST-segment resolution in the Proxis group was 78% compared with 76% in the control group (P=0.88).

"The Proxis system is feasible and safe in the setting of STEMI, and effectively retrieves embolic debris in most patients," Koch said. "Primary PCI with combined proximal embolic protection and aspiration leads to better immediate microvascular flow in STEMI patients."

PREPARE design and endpoints
Koch and colleagues conducted PREPARE to compare primary PCI with the Proxis system (n=141) or without (n=143). The trial design was open, with blinded evaluation of endpoints.

The primary endpoint of PREPARE was ST-segment resolution over time. Secondary endpoints were TIMI graded flow, myocardial blush grade, angiographic signs of distal embolization, and a composite of death, MI, target-vessel revascularization, and stroke at 30 days.

Adverse events at 30 days included two deaths in each cohort, two MIs in the Proxis group vs. three in the control, three target-vessel revascaularizations in the Proxis group vs. six in the control group, six occurrences of MACCE in the Proxis group vs. 10 in the control group, and one stroke in the control group. There were no complications in the Proxis landing zone, Koch said.

Strengths and limitations

Cindy L. Grines, MD, from William Beaumont Hospital, Royal Oak, Mich., said there were a number of strengths associated with PREPARE. It was randomized; it utilized two experienced centers; and the device itself may avoid issues that are unique to distal occlusion balloons and filters. In addition, the researchers had a minimal delay in reperfusion (3 min). There also was a trend for improved TIMI 3 flow and there was improved immediate ST resolution, Grines said.

"Interestingly enough, the Proxis device proved to be extremely safe. There were no complications, it was able to be utilized in 94% of the cases and it was effective at removing thrombus in 75%," she said.

One limitation of the trial was experience with proximal protection. In addition, the relatively small sample size does not allow clinical endpoints to be assessed, Grines said.

Study details
Mean age of the patients was 62 years in the Proxis group and 59 years in the control group. In both arms, 80% of the participants were men. Inclusion criteria consisted of consecutive STEMI patients presenting <6 hours, ST-segment elevation >2 mm in two leads, TIMI flow grade 0 to 1 at first angiogram, coronary anatomy suitable for Proxis, and ECG suitable for ST-segment resolution evaluation, according to Koch. Patients were excluded from the study if they had recurrence of MI in the same area or prior CABG or lytics.

"This is a very unique device," she said. "This trial adds to the wealth of information we are starting to accumulate in this area."