November 16, 2011 — Coronary thrombectomy in conjunction with percutaneous coronary intervention improved the rates of ST-segment elevation resolution when compared to a control group but did not show large differences in reduction of infarct size.
Results of the MUSTELA (A Prospective, Randomized Trial of Thrombectomy vs. no Thrombectomy in Patients with ST-Segment Elevation Myocardial Infarction and Thrombus-Rich Lesions) trial were presented at the 23rd annual Transcatheter Cardiovascular Therapeutics (TCT) scientific symposium. TCT was sponsored by the Cardiovascular Research Foundation.
Thrombectomy is the removal of a blood clot, or thrombus. The trial’s purpose was to determine whether coronary thrombectomy as an adjunct to primary percutaneous coronary intervention (PPCI) in patients with high thrombotic burden improves myocardial perfusion and reduces infarct size. Efficacy was assessed by magnetic resonance imaging (MRI).
In this multi-center prospective trial, researchers randomized 208 consecutive patients with ST-elevation myocardial infarction (STEMI), pain-to-balloon-time <12 hours, and angiographic evidence of high thrombotic burden (thrombus grade ?3). Patients were randomized to either standard PPCI (Group A) or PPCI with thrombectomy (Group B) in a 1:1 ratio. The thrombectomy arm was divided between use of rheolytic and aspiration thrombectomy devices.
The primary endpoints were infarct size at three months (assessed with delayed-enhancement MRI) and ST-segment elevation resolution greater than 70 percent at 60 minutes after primary PCI.
ST-segment elevation resolution of greater than 70 percent occurred in 37.3 percent of the control group and 57.4 percent of the thrombectomy group.
Infarct size (IS) was reduced 19.3 percent in the control group and 20.4 percent in the thrombectomy group. A further analysis showed presence of myocardial vascular obstruction (MVO) in the control group together with less dysomogeneus scar (islands of viable myocardium inside the IS.)
Both thrombectomy systems showed to be feasible with a slight advantage for rheolytic thrombectomy.
“There were no coronary complications associated with thrombectomy,” said Anna Sonia Petronio, M.D., the lead investigator of the trial. Petronio is an associate professor and head of the cath lab in the cardiothoracic and vascular department at the University of Pisa in Italy.
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