JETSTENT Study Demonstrates Benefit of Rheolytic Thrombectomy Before Stenting in STEMI Patients

March 16, 2010—The American College of Cardiology (ACC) announced that findings from the JETSTENT study demonstrated that conducting rheolytic thrombectomy before direct infarct-related artery stenting in patients with acute ST-segment elevation myocardial infarctions (STEMI) produced better clinical results than performing direct stenting alone. JETSTENT's lead investigator David Antoniucci, MD, presented the results at the ACC's 59th annual scientific session in Atlanta, Georgia. Medrad Interventional/Possis (Indianola, PA) funded the JETSTENT trial but was not involved in the management, collection and data analysis. Medrad, Inc. (Warrendale, PA) acquired Possis Medical, Inc., in 2008 to form Medrad Interventional/Possis.

According to the ACC, the randomized, prospective JETSTENT trial enrolled 501 patients at eight sites in Europe and South America between December 2005 and September 2009 to determine how use of a rheolytic thrombectomy system would affect myocardial reperfusion and clinical outcomes for patients with acute STEMI. The trial's primary endpoints were ST-segment resolution at 30 to 45 minutes postprocedure and final infarct size at 30 days. The trial's clinical endpoints included a composite of death, myocardial infarction, target vessel revascularization, and stroke at 1, 6, and 12 months, as well as a composite of death and readmission for congestive heart failure at 12 months. 

The study found that significantly more patients receiving rheolytic thrombectomy in addition to direct stenting experienced resolution of their ST-segment elevation in the designated time frame than those patients receiving stenting alone, at 85.8% and 78.8%, respectively. Additionally, whereas no significant differences were revealed in infarct size as assessed by 1-month scintigraphy (median infarct size was 11%), the investigators found a value of 11.8% in the thrombectomy arm and 12.7% in the direct stenting alone arm. The researchers also found a significant decrease in major cardiovascular adverse events both at 1 month and at 6 months for patients randomized to receive rheolytic thrombectomy than patients in the direct stenting alone arm (3.1% versus 6.9% and 12% versus 20.7%, respectively). The researchers did not find a significant difference between the study's other surrogate endpoints, including myocardial blush grade and the corrected TIMI frame count. 
 
As reported by the ACC, the JETSTENT data contrast with the outcomes of Possis Medical's previous study, the AiMI (AngioJet Rheolytic Thrombectomy in Patients Undergoing PCI for Acute Myocardial Infarction) trial. Specifically, AiMI found that in a sample of 480 patients, rheolytic thrombectomy did not lead to better reperfusion and was associated with a significantly higher mortality rate at 30 days and 6 months postprocedure. 
 
Dr. Antoniucci stated that the JETSTENT study was also designed to address questions raised by the AiMI findings. JETSTENT differs from AiMI in three key ways. First, it includes only patients with angiographically visible thrombus. Second, it uses a "single-pass antegrade" technique in which the thrombectomy device is activated before crossing the lesion and moved in a proximal-to-distal approach in order to cut the risk of embolization. Third, it has a narrow temporal definition of ST-segment elevation resolution (defined as more than 50% resolution within 30 to 45 minutes from the procedure), which allows for greater sensitivity than the 90-minute timeframe that was used in the AiMI study.

"These study results support the routine use of thrombectomy in patients with acute STEMI and evidence of thrombus," commented Dr. Antoniucci. "Early ST-segment resolution was inversely related to the avoidance of major adverse events, suggesting that it is a reliable marker of reperfusion. Also, multivariable analysis showed that randomization to rheolytic thrombectomy is independently related both to early ST-segment resolution and to the avoidance of major adverse cardiovascular events."  
 
In an interview with Cardiac Interventions Today, Dr. Antoniucci commented that the main take-home points of the JETSTENT findings are:

"First, that rheolytic thrombectomy before infarct artery stents implanted was associated with a strong decrease in the measure of major adverse cardiovascular events, both at 1 month and at 6 months. Patients undergoing rheolytic thrombectomy had half the rate of major adverse cardiovascular events. The link between this better outcome may be related to better myocardial perfusion as shown by the better ST-segment resolution, that this is a good surrogate marker of myocardial perfusion. This may explain, at least in part, the better outcome.

"Second, that in patients randomized to the control arm, which included direct stenting and routine abciximab in all patients, these patients had more stents implanted for increased total stent length, and this may have contributed to a measurable increase in unplanned revascularization for thrombosis or restenosis. In JETSTENT, there is benefit in terms of myocardial perfusion—not only because there is a decrease in mortality—but also in terms of recurrent ischemia needing target vessel revascularization."

ACC Panelist William W. O'Neill, MD, praised the JETSTENT trial for being very well conducted and stated that it refocuses interventionists on an issue that has been known for 25 years: the problem of thrombus burden and how to effectively treat it in the acute MI setting.

Dr. O'Neill approved of the choice of ST-segment resolution for a primary endpoint, but he was unsurprised at the null finding for infarct size, because, as he noted, most trials have shown "very little incremental benefit for infarct size reduction in nonanterior MI," which represented 60% of cases in JETSTENT.

The observed reduction in 6-month MACCE is noteworthy, Dr. O'Neil said, because "now we have something that goes along with the TAPAS [Thrombus Aspiration During Percutaneous Coronary Intervention in Acute Myocardial Infarction] trial, which also demonstrated there was some survival benefit at 1 year."