Thrombus aspiration is applicable in a large majority of patients with MI with ST-segment elevation, and it results in better reperfusion and clinical outcomes than conventional percutaneous coronary intervention, irrespective of clinical and angiographic characteristics at baseline, according to a study published in the Feb. 7 issue of the New England Journal of Medicine.
Primary percutaneous coronary intervention (PCI) is typically effective in opening the infarct-related artery in patients with ST-segment elevation myocardial infarction (STEMI).
Tone Svilaas, MD, of the University of Groningen in Groningen, the Netherlands, and colleagues, however, investigated the embolization of atherothrombotic debris, which induces microvascular obstruction and diminishes myocardial reperfusion.
The Thrombus Aspiration during Percutaneous Coronary Intervention in Acute Myocardial Infarction Study (TAPAS) was a single-center, prospective, randomized, open trial involving the blinded evaluation of end points.
The researchers investigated all consecutive patients presenting to the University Medical Center with a possible STEMI between January 2005 and December 2006 . The inclusion criteria were symptoms suggesting acute myocardial ischemia lasting more than 30 minutes, the onset of symptoms less than 12 hours previously, and ST-segment elevation of more than 0.1 mV in two or more leads on the ECG.
During the study period, the researchers enrolled 1,071 patients, who before their coronary angiography, were randomly assigned to undergo either thrombus aspiration during PCI (535 patients) or conventional PCI (536 patients). The baseline clinical and angiographic characteristics were similar in the two groups, the authors wrote.
Svilaas and colleagues found a myocardial blush grade of 0 or 1 occurred in 17.1% of the patients in the thrombus-aspiration group and in 26.3% of those in the conventional-PCI group. Complete resolution of ST-segment elevation occurred in 56.6% and 44.2% of patients, respectively.
The benefit did not show heterogeneity among the baseline levels of the prespecified covariates. At 30 days, the rate of death in patients with a myocardial blush grade of 0 or 1, 2, and 3 was 5.2%, 2.9%, and 1%, respectively, and the rate of adverse events was 14.1%, 8.8%, and 4.2%, respectively. Histopathological examination confirmed successful aspiration in 72.9% of patients.
The authors wrote that they could not identify atherothrombotic material in 27% of patients in whom aspiration was performed.
The researchers said their trial provides a systematic analysis of the role of coronary thrombi in a representative, contemporary population with STEMI, since aspiration was performed soon after the onset of symptoms in a large cohort of patients, who were not selected on the basis of angiographic characteristics and were randomly assigned to a treatment group.
Medtronic of Minneapolis, provided a grant for angiographic analyses by the core laboratory, and the Thorax Center of the University Medical Center Groningen covered all other costs, according to researchers.