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Does Thrombus Aspiration Improve Outcomes of Primary Percutaneous Coronary Intervention?

In a randomized study, aspiration improved perfusion after STEMI, but its direct effect on later outcomes remains unproven.

Microvascular obstruction due to distal thrombus embolization during primary percutaneous coronary intervention impairs myocardial perfusion and is associated with adverse outcomes. In this randomized trial, partially funded by the manufacturer of the study device, 1071 patients with ST-segment-elevation MI were assigned to either manual thrombus aspiration or a conventional procedure (generally, balloon dilation) before stent delivery as appropriate during PCI. All patients received a loading dose of clopidogrel, and abciximab was administered to more than 90%.

Atherothrombotic material was aspirated in 72.9% of patients and mostly consisted of platelet thrombi. The primary study endpoint, myocardial blush grade of 0 or 1, occurred in 17.1% of patients in the thrombus-aspiration group versus 26.3% in the conventional-PCI group (P<0.001). The rate of complete ST-segment resolution postprocedure was higher in the thrombus-aspiration group than in the conventional-PCI group (56.6% vs. 44.2%, P<0.001). Clinical outcomes at 30 days favored the aspiration group, with lower rates of death (2.1% vs. 4.0%), reinfarction (0.8% vs. 1.9%), and overall major adverse events (6.8% vs. 9.4%), but the differences were not statistically significant. However, the rates of death and other adverse events did significantly correlate with blush grade of 0 or 1 and resolution of ST-segment elevation.

Comment: Despite the logical advantage of thrombus aspiration during PCI, previous studies employing various complex devices have failed to confirm superiority of this approach in reducing infarct size or death rates. In this similar study of a simple manual aspiration catheter, a demonstrated benefit in early measures of perfusion resulted only in trends toward a later benefit in outcomes, even with histopathologic evidence of effective aspiration in the majority of patients. In my opinion, routine thrombus aspiration is not yet a proven strategy, particularly if it is associated with any delay in time to reperfusion.

— Howard C. Herrmann, MD

Published in Journal Watch Cardiology February 6, 2008

Citation(s):

Svilaas T et al. Thrombus aspiration during primary percutaneous coronary intervention. N Engl J Med 2008 Feb 7; 358:557.

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• Medline abstract (Free)

Vetrovec GW. Improving reperfusion in patients with myocardial infarction. N Engl J Med 2008 Feb 7; 358:634.

• Original article (Subscription may be required)
• Medline abstract (Free)