March 18, 2010 (Atlanta, Georgia) — The use of rheolytic thrombectomy prior to direct stenting of the infarct-related artery in patients with acute MI is associated with better reperfusion at 30 days and improved short-term clinical outcomes, according to the results of a new study.
"This trial showed a benefit in terms of surrogate end points but was also associated with a strong decrease in mortality at one and six months," said lead investigator Dr David Antoniucci (Careggi Hospital, Florence, Italy).
Presenting the results of the JETSTENT study during the late-breaking clinical-trials session at the American College of Cardiology 2010 Scientific Sessions/i2 Summit, Antoniucci said the risk of major adverse cardiovascular events at six months was halved by thrombectomy and provided an additive benefit beyond standard therapy. The results of the trial, he told the audience, "support the routine use of rheolytic thrombectomy" in STEMI patients with evidence of thrombus.
TAPAS and Some More Data to Feed on
Previous trials have investigated the potential clinical role of thrombus aspiration during PCI. One trial, known as the Thrombus Aspiration during Percutaneous Coronary Intervention in Acute Myocardial Infarction (TAPAS) study, compared stenting for acute STEMI with or without prior application of a thrombus-aspiration catheter. As previously reported by heartwire , 30-day reperfusion and clinical outcomes achieved by extracting the culprit thrombus prior to stenting were sustained to at least one year.
In contrast to TAPAS, however, the AngioJet Rheolytic Thrombectomy in Patients Undergoing Primary Angioplasty for Acute Myocardial Infarction (AiMI) study showed that thrombectomy before PCI did not significantly reduce myocardial infarct size in acute-MI patients. The new JETSTENT study, said Antoniucci, differs from AiMI in that it includes only patients with angiographically visible thrombus. Also, clinicians used a single-pass anterograde approach that activates the device prior to crossing the lesion. The aspiration catheter is moved in a proximal-to-distal manner to prevent embolization.
In JETSTENT, patients were eligible if they presented with STEMI within 12 hours of symptom onset and had a thrombus grade 3 to 5 detected by angiography. In total, 500 patients were randomized to direct stenting or thrombectomy plus direct stenting. The primary end point of the study was early ST-segment resolution, defined as >50% ST-segment-elevation reduction at 30 minutes and infarct size at one month. Secondary end points included major adverse cardiovascular and cerebrovascular events (MACCE) at one and six months.
ST-segment resolution at 30 minutes was significantly improved in patients who underwent thrombectomy prior to direct stenting compared with those who were stented without thrombectomy. Infarct size, however, was not different between the two treatment arms. Regarding clinical end points, MACCE, which included death, MI, target lesion revascularization, and stroke, was also significantly improved at one and six months with thrombectomy.
JETSTENT: Surrogate End Points and MACE
|End point||Thrombectomy plus stent, n=246 (%)||Direct stenting only, n=240 (%)||p|
|>50% ST-segment reduction at 30 min||85.8||78.8||0.043|
|Infarct-size measured by 1-mo scintigraphy||11.8||12.7||0.398|
|MACCE at 1 mo||3.1||6.9||0.05|
|MACCE at 6 mo||12.0||20.7||0.012|
Speaking during the late-breaking clinical-trials session, Antoniucci said that investigators included patients with cardiogenic shock, equally distributed in both treatment arms, and that 40% of patients had multivessel disease. Procedural times were significantly longer for those treated with thrombectomy, about 15 minutes longer, but procedural success rates were similar in both treatment groups.
Should Thrombectomy Be Routinely Used?
Speaking during the discussion, Dr William O'Neill (University of Miami Miller School of Medicine, FL) said the JETSTENT study refocuses the issue on the importance of thrombus burden in STEMI patients. "For 25 years, it's been known that thrombus and thrombus burden is bad in the acute-MI setting, but we never had really good conclusive trials."
Speaking on the strengths of the study, O'Neill said that he "likes the primary end point," because ST-segment resolution has been shown to be an important predictor of one-year survival. Regarding infarct size, he said he was not surprised the researchers did not see a benefit, because 60% of patients included in the study had nonanterior MIs, and most of the data suggest there is little incremental reduction in infarct size in patients with these infarctions. As for the benefit in terms of hard clinical end points, "we now have something that goes along with the TAPAS trial, which also demonstrated there was some survival benefit at one year," said O'Neill.
Dr Gregg Stone (Columbia University, New York), who also spoke during the panel discussion, said statisticians would argue that a study with two primary end points would require a p value of 0.025, and not 0.05, making the JETSTENT study a negative trial. Most important, however, he said there is insufficient evidence to support the routine use of thrombectomy prior to stenting, a conclusion echoed by panel member Dr Peter Clemmensen (Copenhagen University Hospital, Denmark).
"As an invasive cardiologist," said Clemmensen, "I'm not at all convinced that it's valuable with the data available from a small trial, although some have some good results. I don't think we have the data from large-scale trials, with hard end points, and long term, to definitely say that we should be using this routinely in all patients."
Medrad Interventional/Possis funded the study. Antoniucci reports no conflicts of interest.
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Cite this: JETSTENT: Improved Reperfusion and Short-Term Clinical End Points With Thrombectomy - Medscape - Mar 18, 2010.